These beetles are very robust, with a broad pronotum and broadly convex elytra (Fig. 9A). The pronotal base is broad, with MPW/BPW = 1.30–1.32, and the hind angles are projected, with the pronotal lateral margin concave just before the angle. Only the posterior supraorbital seta is present, and the pronotum is glabrous. Elytral striae 1–5 are well developed basally, with striae 3–5 deeper than those of individuals of the similar appearing M. laterosinuatus and M. laterorectus (Fig. 9B–C). Standardized body length 4.1–4.4 mm. Chaetotaxy –/+//–/–//+/2/+/+.

(n = 5). Head capsule broad, eyes moderately convex, ocular lobe meeting gena at very obtuse angle; 16 ommatidia along horizontal diameter of eye; ocular ratio 1.33–1.42, EyL/EyD = 2.34–3.0; frontal grooves deep, arcuately convergent and deepest just posterad clypeus, briefly and shallowly extended onto clypeus; mandibles moderately elongate, mandibular ratio 1.67; ligular anterior margin rounded to ligular seta, concave between setae, the two setae separated by two setal diameters; paraglossae thin, extended as far beyond ligular margin as their basal length to margin; antennae moderately elongate, antennomere 9 length 2.0× maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum moderately constricted basally, with obtuse-rounded hind angles and lateral margins briefly sinuate anterad angles (Fig. 9A); MPW/BPW = 1.30–1.32, MPW/PL = 1.19–1.22; front angles protruded anteriorly, but anterior margin narrowly approaching head capsule, APW/BPW = 0.69–0.71; basal margin broadly convex, beaded from just mesad deep, longitudinal laterobasal depression to and around obtuse-rounded hind angle; median longitudinal impression deep and narrow on disc, broader and shallower approaching base, absent anterad very shallow anterior transverse impression; proepisternum separated from prosternum by a very shallow groove anteriorly, but with a deep, slightly punctate groove ventrally; prosternal process deeply and narrowly depressed between procoxae, that depression extended 1/3 distance toward anterior prothoracic margin. Elytra broadly ovoid, humeri broad, humeral angle obtusely rounded laterad pronotal hind angles; MEW/EL = 0.87–0.93; basal groove evenly arcuate from scutellum to humeral angles, with depression at bases of sutural and elytral striae 4–5; sutural stria deep throughout length, stria 2 obsolete though traceable, stria 3 somewhat deeper, striae 4–5 deep in basal half, striae 6–7 obsolete; only sutural stria and stria 8 evident apically, elytra appressed and conjoined apically, sutural intervals narrower and upraised at apex. Pterothoracic mesepisternal anterior furrow with 6–7 deep punctures; mesosternal-mesepisternal suture complete (as in Fig. 3A); metepisternum maximum width/lateral length = 1.0; metepisternal-metepimeral suture incomplete, shallower and incomplete laterally. Abdomen with deep crescent-shaped depression along suture between first and second ventrite, second ventrite depressed within crescent; suture between second and third ventrites reduced though traceable laterally; ventrites 2–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons a shallow transverse mesh, sculpticells twice as broad as long, these mixed with isodiametric sculpticells on vertex; pronotal disc and base covered with elongate transverse mesh plus transverse lines, surface iridescent; elytral iridescent, disc with loose elongate transverse mesh, apex with very elongate transverse mesh, sculpticell breadth 3–4× length.

Figure 3. 

Thoracic structures of Mecyclothorax spp. A–B. Lateral view of elytral epipleuron and meso-and metapleurites: A, M. laterorectus; B, M. fleutiauxi. C–D. Metathoracic flight wing: C, M. punctipennis, showing fully developed flight wing folded under elytron; D, M. lissus, stenopterous wing rudiment that extends beyond metanotum, rudimentary wing venation present at base of strap. Abbreviations include: mms, mesepisternal-mesosternal suture; msp, mesepimeron; mst, mesepisternum; mtp, metepimeron; mtt, metepisternum.

Figure 4. 

Male aedeagal median lobe and parameres of Mecyclothorax spp., right lateral view, internal sac everted in C–G: A, M. blackburni; B–C, M. peryphoides; D, M. moorei; E, M. lewisensis; F, M. punctipennis; G, M. montivagus. See Table 2 for abbreviations.

Figure 5. 

Paired left (above) and right (below) parameres of Mecyclothorax spp. (ectal view): A, M. blackburni; B, M. storeyi; C, M. amplipennis; D, M. montivagus; E, M. laterobustus. As the aedeagal assembly of M. storeyi males is inverted relative to other Mecyclothorax species (Moore 1984), the configuration of the upper, or right paramere of M. storeyi should be compared to the ventral, or left parameres of the other species, and vice versa.

Figure 6. 

Female reproductive tract, gonocoxites and associated laterotergites, Amblytelus and Mecyclothorax spp: A, A. matthewsi; B, A. brevis; C, M. blackburni; D, M. storeyi; E, M. minutus; F, M. rectangulus. See Table 2 for abbreviations.

Figure 7. 

Strict consensus cladogram of 16 equally most-parsimonious trees derived from cladistic analysis of 65 moriomorphine taxa, including the secondary outgroup Neonomius laevicollis, six primary outgroup taxa in Amblytelus and allied genera, and 58 ingroup terminals; 57 Mecyclothorax species plus two genitalic forms of M. andersoni. Species terminals are labeled with species name and three-letter abbreviation of relevant generic or subgeneric name. Full listing of included taxa along with subgeneric assignments is presented in Table 2. Cladistic analysis is based on 137 characters (see character descriptions for nature of each character Areas occupied by the included taxa indicated by abbreviations following species epithets: Bo, Borneo; EOZ, eastern Australia, i.e. east of the Nullarbor Plain; FP, French Polynesia, Tahiti; HI, Hawaiian Islands, Maui; Jv, Java; LH, Lord Howe Island; NC, New Caledonia; Nf, Norfolk Island; NNZ, North Island of New Zealand; NZ, generally distributed across New Zealand; OZ, generally distributed across Australia; PNG, Papua New Guinea; QOZ, restricted to Queensland, Australia; SNZ, South Island of New Zealand plus Chatham Islands; SP&A, St. Paul and Amsterdam Islands; WOZ, western Australia, i.e. west of the Nullarbor Plain.

Figure 8. 

Mecyclothorax spp., dorsal view, with subgeneric assignments: A, M. (Eucyclothorax, subgen. n.) blackburni (type species); B, M. (Qecyclothorax, subgen. n.) storeyi (type species); C, M. (Meonochilus, status n.) amplipennis (type species); D, M. (Mecyclothorax) montivagus (type species); E, M. (Mecyclothorax) lissus.

Male genitalia (n = 1). Antecostal margin of male mediotergite IX distally angulate, little extended (Fig. 10B); right paramere very elongate, moderately narrow, with a single seta on dorsal margin distant from two apical setae (Fig. 5E); left paramere narrow basally, evenly narrowed to a whip-shaped apex, two longer setae at apex; aedeagal median lobe shaft robust, broad dorsoventrally (Fig. 10A), median lobe apex broad, sides subparallel, with tip broadly rounded; aedeagal internal sac with flagellum, flagellar sheath, and sclerotized dorsal plate.

Female reproductive tract (n = 1). Bursa copulatrix elongate, length more than twice circumference, surface translucent, membranous (Fig. 12A); spermathecal duct entering near bursa-common oviduct juncture with duct oriented toward right side of bursa, duct longer than spermathecal reservoir; a rounded laminar helminthoid sclerite present at base of spermathecal duct; spermatheca fusiform on narrow duct, spermathecal gland duct entering at base of spermathecal reservoir; basal gonocoxite 1 with apical fringe of two setae near medial margin, a series of small setae lining medial margin (Fig. 13A); gonocoxite 2 moderately broad basally, basal width about half medial length; two gracile lateral ensiform setae of moderate length present.

Types – Holotype male (MNHN): NEW CALEDONIA / Ningua Res.camp / 12-13Nov 2001 / G.B.Monteith // QM Berlesate 1039 / 21°45’Sx166°09’E / Rainforest, 1100m / Sieved litter // QUEENSLAND / MUSEUM LOAN / Date: Nov. 2003 / No. LEN-1686 (green label) // HOLOTYPE / Mecyclothorax / laterobustus / J.K.Liebherr 2017 (black-bordered red label).

Paratypes (10 specimens). NEW CALEDONIA: Ningua Reserve, camp, 1100 m el., 21°45’S 166°09’E, rainforest, sieved litter, 12-13-xi-2001, lot 1039, Monteith (QMB, 4), near summit, rainforest, 1300 m el., 21°45’S 166°09’E, berlesate, sieved litter, 13-xi-2001, lot 1052, Monteith (QMB, 3); Plateau de Dogny, rainforest, 910 m el., 21°37’S, 165°53’E, berlesate sieved litter, 16-xi-2002, lot 1085, Burwell (QMB, 3).

The very broad and robust body form of these beetles (Fig. 9A) suggests the compound, adjectival species epithet laterorobustus.

This species is known from two localities, Ningua Reserve and Plateau de Dogny (Fig. 14), and specimens have been collected from 900–1300 m elevation. The three collecting events are all based on recovering specimens from sieved litter, consistent with an interpretation that these beetles occupy ground-level microhabitats.

These beetles are very similar in external appearance to those of M. laterorectus (Fig. 9B–C) below, sharing the moderately robust body form and cordate pronotum, though the pronotal base is slightly broader relative to the maximal pronotal width in this species: MPW/BPW = 1.28–1.33. This species also differs from M. laterorectus in the very shallow second elytral stria contrasted to the deeper sutural stria and striae 3–6. Like the preceding M. laterobustus, the pronotal hind angles protrude, with the pronotal lateral margin concave before the angle, but in this species and the following, the pronotal lateral seta is present. Also, this and the following species exhibit both anterior and posterior supraorbital setae. Standardized body length 3.7–4.3 mm. Chaetotaxy +/+//+/–//+/2/+/+.

Figure 9. 

New Caledonian Mecyclothorax (Phacothorax) spp., dorsal view: A, M. laterobustus; B, M. laterosinuatus; C, M. laterorectus; D, M. fleutiauxi; E, M. jeanneli.

(n = 5). Head capsule broad, eyes convex, ocular lobe meeting gena at obtuse angle very close to eye posterior margin; 12–14 ommatidia along horizontal diameter of eye; ocular ratio 1.43–1.50, ocular lobe ratio 0.84–0.89, EyL/EyD = 2.50–2.65; frontal grooves nearly straight from posterior terminus inside anterior supraorbital seta to deepest point just posterad clypeus, briefly and shallowly extended onto clypeus; mandibles moderately elongate, mandibular ratio 1.8; ligular anterior margin narrowly rounded to ligular seta, concave between setae, the two setae separated by two setal diameters; paraglossae thin, extended as far beyond ligular margin as their basal length to margin; antennae elongate, antennomere 9 length 2.25× maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum distinctly constricted basally, cordate, hind angles obtuse rounded, lateral pronotal margins subparallel anterad hind angles, then distinctly divergent anteriorly (Fig. 9B); MPW/BPW = 1.37–1.40, MPW/PL = 1.24–1.27; front angles protruded, obtusely angulate, APW/BPW = 0.75–0.78; basal margin slightly convex, nearly straight between broadly upraised hind margins posterad broad laterobasal depressions; laterobasal depression with longitudinal tubercle inside hind angle, and broad furrowlike longitudinal extension onto disc; median longitudinal impression fine and shallow on disc, with deep longitudinal pitlike depression anterad median base, absent anterad very broad and shallow anterior transverse impression; proepisternum separated anteriorly from prosternum by fine shallow groove, distinctly separated ventrally by smooth, deep groove; prosternal process deeply, narrowly between procoxae, that deep depression extended 1/3 distance toward anterior prothoracic margin. Elytra broadly ellipsoid, humeri extended laterally, humeral angle obtusely rounded outside pronotal hind angles; MEW/EL = 0.81–0.86; basal groove evenly arcuate from scutellum to humeral angles, with depressions at bases of sutural and elytral striae 3–5; sutural stria deep throughout length, stria 2 shallow, obsolete on disc, striae 3–5 deep, stria 6 shallow, and stria 7 obsolete in basal half; striae 1–2, 7 and 8 evident apically, elytra appressed and conjoined apically, sutural intervals narrower and upraised at apex. Pterothoracic mesepisternal anterior furrow with five broad depressions in one to two vertical rows; metepisternum maximum width/lateral length = 1.1; mesosternal-mesepisternal suture complete (as in Fig. 3A); metepisternal-metepimeral suture incomplete, shallower and incomplete laterally. Abdomen with deep crescent-shaped depression along suture between first and second ventrite, second ventrite depressed within crescent; suture between second and third ventrites reduced, incomplete laterally; ventrites 2–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons an evident transverse mesh, transverse sculpticells mixed with isodiametric sculpticells on vertex; pronotal disc and base covered with elongate transverse mesh plus transverse lines, surface iridescent; elytra iridescent, disc with loose elongate transverse mesh, apex with very elongate transverse mesh, sculpticell breadth 3–4× length. Femora rufobrunneous basally, with a broad flavous band in apical third.

Male genitalia (n = 5). Antecostal margin of abdominal mediotergite IX angulate distally, an elongate distal extension present (Fig. 10E); right paramere very elongate, apical half narrowed into a whiplike extension (Fig. 11A), with 10 setae on ventral surface complementing the two apical setae, dorsal surface with four small setae; left paramere narrow basally, evenly extended to whiplike apex, surfaces glabrous except for two apical setae; aedeagal median lobe robust, broad dorsoapically, apex broadly curved ventrally with tip rounded (Fig. 10C–D); aedeagal median lobe internal sac with flagellum, flagellar sheath, and dorsal plate, the former two structures curved dorsad apically. The median lobes of the two figured males–Col d’Amieu (Fig. 10C) and Touho TV Tower (Fig. 10D) – differ about 10% in length, whereas the males themselves are nearly identical in standardized body length; 4.0 versus 4.05 mm. As the internal sac structures do not appear to differ except in the basal shape of the dorsal plate (differing orientation inside median lobe?), these two populations are considered conspecific.

Figure 10. 

Male aedeagal median lobe and parameres, and ring sclerite–mediotergite plus antecostal margin, tergite IX–of Mecyclothorax (Phacothorax) spp.: A–B, M. laterorobustus, right view, dorsal view in situ (Ningua); C, M. laterosinuatus, right view (Col d’Amieu); D, M. laterosinuatus, right view (Touho TV tower); E, M. laterosinuatus ring, dorsal view; F, M. laterorectus, right view (Mt. Panié); G–H, M. laterorectus, right vew, dorsal view in situ (Mandjélia); I–J, M. fleutiauxi, right view, dorsal view in situ (Mt. Do); K–L, M. fleutiauxi, right view, sac inverted and everted (Me Maoya); M, M. fleutiauxi, right view (Ningua); N–O, M. jeanneli, right view, dorsal view in situ (Mt. Humboldt, 1350 m); P, M. jeanneli, right view (Mt. Humboldt, 1300 m); Q, M. jeanneli, right view, sac everted (Mt. Dzumac); R, M. jeanneli, right view (Rivière Bleue). See Table 2 for abbreviations.

Figure 11. 

Paired left (above) and right (below) parameres of Mecyclothorax (Phacothorax) spp. (ectal view): A, M. laterosinuatus; B, M. laterorectus; C, M. fleutiauxi; D, M. jeanneli.

Female reproductive tract (n = 2). Bursa copulatrix elongate, length about twice circumference, surface translucent, membranous (Fig. 12B); spermathecal duct entering near bursa-common oviduct juncture with duct oriented toward right side of bursa, duct as long as spermathecal reservoir; an elongate laminar helminthoid sclerite present at base of spermathecal duct; spermatheca fusiform on narrow duct, spermathecal gland duct entering at base of spermathecal reservoir; ligular apophysis present near base of common oviduct; basal gonocoxite 1 with apical fringe of one to two short setae laterally on apical margin, smaller microsetae scattered along apical margin, and a series of small setae lining medial margin (Fig. 13B); gonocoxite 2 broad basally, basal width slightly more than half medial length; two short, gracile lateral ensiform setae present.

Figure 12. 

Female reproductive tract, gonocoxites and associated laterotergites, Mecyclothorax (Phacothorax) spp: A, M. laterobustus; B, M. laterosinuatus; C, M. laterorectus; D, M. fleutiauxi; E, M. jeanneli; F, M. plurisetosus; G, M. megalovatulus. See Table 2 for abbreviations.

Figure 13. 

Left female gonocoxa, ventral view, Mecyclothorax (Phacothorax) spp.: A, M. laterobustus; B, M. laterosinuatus; C, M. laterorectus; D, M. fleutiauxi; E, M. jeanneli ; F, M. plurisetosus; G, M. megalovatulus. See Table 2 for abbreviations.

Types – Holotype male (MNHN): NEW CALEDONIA / Aoupinie top camp / 2-3Nov 2001 / G.B.Monteith // QM Berlesate 1060 / 21°11’Sx165°18’E / Rainforest, 850m / Sieved litter // QUEENSLAND / MUSEUM LOAN / DATE: Nov. 2003 / No. LEN-1686 (green label) // New Caledonia Mecyclothorax revision / measured specimen 2 / J.K. Liebherr 2016 // HOLOTYPE / Mecyclothorax / laterosinuatus / J.K.Liebherr 2017 (black-bordered red label).

Paratypes (83 specimens; BPBM, MNHW, PMGC, QMB): see Suppl. material 2.

Like the preceding and immediately following species, beetles of this species exhibit a basally broad pronotum (Fig. 9A–C). In this species, the distinctly sinuate lateral pronotal margin leads to the compound adjectival species epithet laterosinuatus.

This species is broadly distributed along mid-latitudinal Grand Terre, from Touho TV tower on the north to Mt. Rembai on the south (Fig. 14), with beetles found from 400 m elevation to the summits of the occupied uplands. Of the 76 known specimens, 67 have been collected from sieved litter, indicating occupation of the ground-level microhabitat. Exceptions with situational label data include a singleton found via headlamp search at night (Will, EMEC), and two beetles collected from two flight-intercept traps (Monteith, QMB; Théry, MNMH), no doubt after crawling into the collecting tray.

Figure 14. 

Geographical distributions of Mecyclothorax (Phacothorax) spp.

This third of the species characterized by robust body and a cordate, broad-based pronotum with well-defined hind angles (Fig. 9A–C), can be diagnosed by the relatively narrower pronotal base: MPW/BPW = 1.37–1.40 (Fig. 2A). Like the immediately preceding M. laterosinuatus there are two supraorbital setae each side, and the pronotal lateral seta is present, but the discal elytral striae 3–5 are much shallower here, only slightly deeper than the shallow stria 2. The pronotal lateral margins are subparallel basally, with the pronotal hind angle obtuse, its apex not projected. Standardized body length 4.1–4.4 mm. Chaetotaxy +/+//+/–//+/2/+/+.

(n = 5). Head capsule broad, eyes very convex, popeyed, ocular lobe meeting gena at obtuse angle close to eye posterior margin; 14 ommatidia along horizontal diameter of eye; ocular ratio 1.37–1.45, ocular lobe ratio 0.81–0.90, EyL/EyD = 2.56–2.89; frontal grooves nearly straight from posterior terminus inside anterior supraorbital seta to deepest point just posterad clypeus, briefly and shallowly extended onto clypeus; mandibles moderately elongate, mandibular ratio 1.7; ligular anterior margin narrowly rounded to ligular seta, concave between setae, the two setae separated by one to two setal diameters; paraglossae thin, extended as far beyond ligular margin as their basal length to margin; antennae moderately elongate, antennomere 9 length 2.0× maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum distinctly constricted basally, cordate, hind angles protruded and nearly right, lateral margins distinctly, briefly sinuate anterad angles (Figs 2A, 9B); MPW/BPW = 1.37–1.40, MPW/PL = 1.19–1.25; front angles only slightly protruded, rounded, APW/BPW = 0.72–0.77; basal margin broadly convex, margin broadly upraised behind broad laterobasal depression, the depression extended longitudinally onto disc as a broad sinuous furrow; median longitudinal impression fine and shallow on disc, continued to basal margin (a shallow transverse impression inside basal margin), absent anterad very shallow anterior transverse impression; proepisternum incompletely separated anteriorly from prosternum, but by a deep, smooth groove ventrally; prosternal process broadly, shallowly depressed between procoxae, that depression extended 1/3 distance to anterior prothoracic margin. Elytra broadly ellipsoid to obovoid, humeri narrow, humeral angle obtusely rounded behind pronotal hind angles; MEW/EL = 0.82–0.86; basal groove evenly arcuate from scutellum to humeral angles, with depressions at bases of the sutural and elytral striae 4–5; sutural stria deep throughout length, striae 2–3 shallow but evident on disc, striae 4–7 deep in basal half; striae 1–2, 7 and 8 evident apically, elytra appressed and conjoined apically, sutural intervals narrower and upraised at apex. Pterothoracic mesepisternal anterior furrow with 5 broad depressions in 1–2 vertical rows; metepisternum maximum width/lateral length = 1.0; mesosternal-mesepisternal suture complete (as in Fig. 3A); metepisternal-metepimeral suture incomplete, shallower and incomplete laterally. Abdomen with deep crescent-shaped depression along suture between first and second ventrite, the second ventrite depressed within crescent; suture between second and third ventrites reduced, incomplete laterally; ventrites 2–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons an evident transverse mesh, transverse sculpticells mixed with isodiametric sculpticells on vertex; pronotal disc and base covered with elongate transverse mesh plus transverse lines, surface of tubercle in laterobasal depression with less transverse sculpticells, surface iridescent; elytra iridescent, disc with loose elongate transverse mesh, apex with very elongate transverse mesh, sculpticell breadth 3–4× length. Femora rufobrunneous basally, with a broad flavous band in apical third.

Male genitalia (n = 3). Antecostal margin of abdominal mediotergite IX angulate, little extended distally (Fig. 10H); right paramere narrowly extended apically (Fig. 11B), with five setae on ventral margin and three on dorsal margin complementing two apical setae; left paramere narrow basally, evenly narrowed to a whiplike apex; aedeagal median lobe robust, broad dorsoventrally, apex distinctly curved ventrad to a narrowly rounded tip, its apical face slightly flattened; aedeagal median lobe internal sac with flagellum, flagellar sheath, and dorsal plate, flagellum and flagellar sheath curved ventrad apically (Fig. 10F–G), a patch of stout macrospicules present just inside ostial opening apicad flagellar structures. The median lobe apex is extended more in the specimen from Mt. Panié (Fig. 10F) than in the Mandjélia male (Fig. 10G). A third male from Mandjélia summit, 750–780 m elevation (MNHW) exhibits a lobe apex of intermediate extension. This continuous variation coupled with the extreme similarity of internal sac structures argues for conspecificity of these populations.

Female reproductive tract (n = 1). Bursa copulatrix elongate, length more than twice circumference, surface translucent, wrinkled, membranous (Fig. 12C); spermathecal duct entering near bursa-common oviduct juncture with duct oriented toward right side of bursa, duct as long as spermathecal reservoir; an elongate laminar helminthoid sclerite present near base of spermathecal duct; spermatheca fusiform on narrow duct, spermathecal gland duct entering at base of spermathecal reservoir; ligular apophysis present near base of common oviduct; basal gonocoxite 1 with apical fringe of two to three setae laterally on apical margin, middle seta of series largest, several small setae scattered along medial margin (Fig. 13C); gonocoxite 2 moderately narrow basally, medial length more than twice basal width; two broad lateral ensiform setae present, apical seta larger.

Types – Holotype male (MNHN): NEW CALEDONIA / Mt. Panié / 16 May 1984 / G. monteith & D. Cook // Q.M. BERLESATE No. 650 / 20.35S X 164.47E / Rainforest, 900 m / Litter // QUEENSLAND / MUSEUM LOAN / DATE: Nov. 2003 / No. LEN-1686 (green label) // genitalia in polyethylene vial with glycerine // HOLOTYPE / Mecyclothorax / laterorectus / J.K.Liebherr 2017 (black-bordered red label).

Paratypes (21 specimens). NEW CALEDONIA: Hienghène [vicinity, code PA 63], 150 m el., 20°41’S 164°57’E, 02-ix-1970, Franz (NHMW, 4); Mandjélia, 700 m el., 20°24’S 164°32’E, 12-v-1984, rainforest, Q.M. berlesate 648, sieved litter, Monteith & Cook (QMB, 2), montane rainforest, 700-780 m el., 20°24’S 164°32’E, Pandanus, 20-xi-2008, Wanat (MNHW, 1), 750-780 m el., 20°24’S 164°32’E, 01-xi-2007, sieved litter, Wanat (MNHW, 5), summit, 750 m el., 20°24’S 164°32’E, hand collecting, 06-07-xi-2001, lot 8750, Burwell & /Monteith (QMB, 1), rainforest, sieved litter, 06-07-xi-2001, lot 1055, Monteith (QMB, 3), flight intercept trap, 29-xi-2003–11-i-2004, lot 11486, Monteith (QMB, 1), 780 m el., 20°24’S 164°32’E, berlesate, sieved litter, 12-xii-2004, lot 11941, Monteith (QMB, 2); Mt. Panié, rainforest, 900 m el., 20°33’S 164°45’E, Q.M. berlesate 650, litter, 16-v-1984, Monteith & Cook (QMB, 1); Roche d’Ouaïème, near Hienghène [PA 65], 500-700 m el., 20°37’S 164°52’E, 03-ix-1970, Franz (NHMW, 1).

As in the preceding two species (Fig. 9A–C), the broad pronotal base leads to the use of latero- to modify the adjectival rectus, which denotes the right pronotal hind angles of these beetles.

This species is distributed in the northern reaches of the Chaîne Centrale, from Mandjélia south to near Hienghène (Fig. 14). Elevations range 700–900 m for credible collecting localities where complete information was provided on the specimen label. Of the 22 specimens known, 14 were recovered from sieved litter. Other collecting situations include hand collecting (1, QMB), flight intercept trap (1, QMB), and association with Pandanus (Pandanaceae) screw palm (1, MNHW).

Though markedly different from all other New Caledonian species, this and the following M. jeanneli (Fig. 9D–E) are indistinguishable externally. Both species are characterized by presence of only the single posterior supraorbital seta (Fig. 1B), and by the orbicular pronotum with a broadly margined base, and evenly ellipsoid elytra. The elytral striae are very shallow, though traceable to the fifth stria. That this and the following species are distinct is supported by characters of the male and female genitalia. In the males, the aedeagal median lobe has the apex elongate, variably extended beyond the apical margin of the ostium (Fig. 10I–M). The female reproductive tract in this species is characterized by presence of a short dorsal lobe of the bursa copulatrix, with the spermathecal duct joined to the lobe’s apex (Fig. 12D). Standardized body length 4.2–5.0 mm. Chaetotaxy –/+//+/–//+/1–2/+–/+.

(n = 10). The description for M. jeanneli (below) serves to describe the external anatomy of this species, with the following exceptions: 18–20 ommatidia along horizontal diameter of eye; ocular ratio 1.43–1.52, ocular lobe ratio 0.89–0.94, EyL/EyD = 3.09–3.33; MPW/PL = 1.24–1.30; MEW/EL = 0.68–0.73; either one or two dorsal elytral setae associated with third interval; if one, the posterior seta is absent (in 2 of 10 specimens scored).

Male genitalia (n = 17). Antecostal margin of abdominal mediotergite IX robust distally, broadly angulate and truncate (Fig. 10J); right paramere very elongate, apical half narrowed to a whiplike extension (Fig. 11C), six setae along ventral margin well separated from apical pair of setae, dorsal surface glabrous; left paramere broad basally, distinctly narrowed to a whiplike extension; aedeagal median lobe moderately gracile, apical half evenly narrowed to extended tip that protrudes at least twice its dorsoventral dimension beyond the apex of the ostial opening (Fig. 10I–M); aedeagal internal sac bilobed, the dorsal lobe much larger than apical lobe (Fig. 10L), a small crescent-shaped structure with lightly sclerotized outer margin–interpreted as a reduced flagellar sheath–dorsad gonopore on apical lobe. Although there is variation in the amount of apical extension and apical curvature of the median lobe among males assigned to this species (Fig. 15), that variation occurs both within and between populational samples indicating that the variation is infraspecific.

Female reproductive tract (n = 5). Bursa copulatrix bilobate, an elongate ventral lobe with length more than twice circumference, and a short dorsal lobe that is about as long as broad and which bears the spermathecal duct at its apex (Fig. 12D); bursal walls moderately thick, wrinkled, semitranslucent; spermathecal duct that enters apex of bursal dorsal lobe about half the diameter of spermathecal reservoir, and about twice length of reservoir, spermathecal gland duct entering onto apex of spermathecal reservoir; well-developed ligular apophysis present on common oviduct as far distant from base of common oviduct as apex of ventral bursal lobe; basal gonocoxite 1 with apical fringe of two setae, a few microsetae near apicomedial margin of gonocoxite complementing very few medial setae (Fig. 13D); apical gonocoxite 2 falciform with an elongate laterobasal extension, basal width more than 0.75× length; two lateral ensiform setae elongate.

Type – Holotype male (MNHN): La Foa à Canala / fev. 1907 La Foa // TYPE (red label) // Phacothorax / Fleutiauxi / Jeannel (male dissected with genitalia separately mounted on card with label “Phacothorax / fleutiauxi ? Jeann.”). So that the separated genitalia can remain unambiguously associated with the male holotype body, a black-bordered red holotype label has been added to that pin.

Additional taxonomic material (145 specimens; EMEC, MNHW, QMB): see Suppl. material 2.

This species is recorded from middle latitudes of Grand Terre, from Aoupinié on the north to Ningua Reserve on the south (Fig. 15), its range a northerly parapatric disjunct to the range of its adelphotaxon, M. jeanneli. Species records indicate a broad altitudinal range among populations, from 485–1400 m elevation. Of 135 specimens with detailed ecological data, 127 have been collected via application of pyrethrin spray to tree trunks or downed logs, whereas none have been recovered from sieved litter. Thus this species is associated with epiphytic growth, bark, or loose bark on plants. That these beetles climb is shown by a record of one taken in an axil of a Freycinetia (Pandanaceae) plant (QMB).

The diagnosis for M. fleutiauxi serves to summarize external diagnostic characters for this species (Fig. 9D–E). Internally, the male aedeagal median lobe has a much shorter apex in beetles of this species, with the tip extended beyond the apical ostial margin only as much as the width of the median lobe at that point (Fig. 10N–R). The female reproductive tract differs in that the dorsal lobe of the bursa copulatrix is as long as the ventral or principal lobe (Fig. 12E), with the spermathecal duct again entering at its apex. Standardized body length 4.4–5.3 mm. Chaetotaxy –/+//+/–//+/1–2/+/+.

(n = 10). Head capsule narrowly elongate, with large, moderately convex eyes, ocular lobe meeting gena at obtuse angle, a broad shallow groove indicating juncture; 20 ommatidia along horizontal diameter of eye; ocular ratio 1.42–1.51, EyL/EyD = 2.8–3.4; frontal grooves sinuously canaliculate, deepest posterad frontoclypeal suture at a line between posterior margin of antennal fossae, briefly prolonged onto clypeus (as in Fig. 1B); mandibles elongate, mandibular ratio 1.9; ligular anterior margin angularly rounded to ligular seta, concave between setae, the two setae separated by two setal diameters (as in Fig. 1I); paraglossae thin, extended as far beyond ligular margin as half of basal length to margin; antennae moderately elongate, antennomere 9 length 2.05× maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum vase-shaped, lateral margins meeting base in a smooth convex curve, hind angles nonexistent (Fig. 9E); MPW/PL = 1.23–1.30; front angles protruded, obtusely rounded; basal margin bordered by broadly convex marginal bead that joins fine lateral marginal beads at very small, shallow laterobasal depressions; median longitudinal impression fine and shallow on disc, terminated anteriorly at a small depression at position of anterior transverse impression; anterior transverse impression broad, very shallow, traceable to front angles; proepisternum separated from prosternum by a broad shallow groove both anteriorly and ventrally; prosternum with shallow anteapical impression laterally, impression absent from ventral 2/3 of circumference; prosternal process broadly depressed between procoxae, that depression extended anteriorly where it broadens to a depressed anterior face extended nearly to prothoracic anterior margin. Elytra elongate, ovoid, humeri quickly sloping posterad outside humeral angles; MEW/EL = 0.70–0.75; basal groove very briefly recurved laterad scutellum, humeral angle tightly rounded; all striae broad and shallow on disc, intervening intervals only slightly convex; one to two dorsal elytral setae present in third interval, if one, the posterior seta is absent (in 3 of 10 specimens scored); shallow remnants of the sutural stria plus striae 2 and 7 traceable at apex; elytra appressed and conjoined apically, sutural intervals narrower and distinctly upraised at apex. Pterothoracic mesepisternal anterior surface smooth; mesosternal-mesepisternal suture incomplete, obsolete to absent anteriorly (as in Fig. 3B); metepisternum very foreshortened, maximum width/lateral length = 1.3; metepisternal-metepimeral suture complete. Abdomen with broad crescent-shaped depression along suture between first and second ventrite, second ventrite broadly depressed behind crescent; suture between second and third ventrites reduced though traceable laterally; ventrites 2–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons distinct, a mix of isodiametric and transverse sculpticells; pronotal disc and base covered with elongate transverse mesh, sculpticells on disc 3–4× broad as long, those on base somewhat less broad, surface iridescent; elytra iridescent, disc covered with transverse-line microsculpture, apex with transverse lines loosely joined into a transverse mesh.

Male genitalia (n = 23). Antecostal margin of abdominal mediotergite IX robust distally, broadly angulate and obliquely truncate (Fig. 10O); right paramere very elongate, apical half narrowed to a whiplike extension (Fig. 11D), five setae along ventral margin well separated from apical pair of setae, dorsal surface glabrous; left paramere broadly quadrate basally, distinctly narrowed to a whiplike extension; aedeagal median lobe moderately gracile, apical half evenly narrowed to tip that protrudes less than its dorsoventral dimension beyond the apex of the ostial opening (Fig. 10N–R); aedeagal internal sac bilobed, the dorsal lobe subequal to the apical lobe (Fig. 10Q), a small crescent-shaped structure with lightly sclerotized outer margin–interpreted as a reduced flagellar sheath–dorsad gonopore on apical lobe. There is less variation among males with regard to extension of the median lobe apex (Fig. 15) – understandable due to the generally shorter extension–and this variation is not geographically associated. Thus the species geographic limits include all populations lying south and east of Mt. Humboldt (Fig. 15).

Figure 15. 

Recorded geographical distribution of M. fleutiauxi (including population samples A–E northwest of dashed boundary) and M. jeanneli (including population samples F–K southeast of dashed boundary): numbers of males sampled for each locality indicated in lower left of boxes. Sampled population localities for M. fleutiauxi include: A, Me Maoya; B, Rembai; C, Gelima; D, Mt. Do; E, Ningua. Sampled population localities for M. jeanneli include: F, Mt. Humboldt, 600 m; G, Mt. Humboldt, 1300–1600 m; H, Mt. Ouin; I, Mt. Dzumac; J, Rivière Bleue; K, Mts. Koghis.

Female reproductive tract (n = 8). Bursa copulatrix bilobate, a broad ventral lobe complemented by narrower dorsal lobe of subequal length, dorsal lobe bearing spermathecal duct at apex (Fig. 12E); bursal walls moderately thick, wrinkled, semitranslucent; spermathecal duct that enters apex of bursal dorsal lobe slightly broader than spermathecal reservoir, and about twice length of reservoir, spermathecal gland duct entering onto apex of spermathecal reservoir; well-developed ligular apophysis present on common oviduct as far distant from base of common oviduct as apex of ventral bursal lobe; basal gonocoxite 1 with apical fringe of two setae, a few microsetae near apicomedial margin of gonocoxite complementing very few medial setae (Fig. 13E); apical gonocoxite 2 falciform with an elongate laterobasal extension, basal width more than 0.75× length; lateral ensiform setae elongate and broad.

Types – Holotype male (MNHN): NEW CALEDONIA.9944 / 22°11’Sx166°01’E [sic, crossed out and hand corrected to 31’E] / Mt Koghi, 750m / 29Nov2000.GB Monteith / Pyrethrum, trunks&logs // QUEENSLAND / MUSEUM LOAN / DATE: Nov. 2003 / No. LEN-1686 (green label) // HOLOTYPE / Mecyclothorax / jeanneli / J.K.Liebherr 2017 (black-bordered red label). The type locality longitude is incorrect on the label, and is corrected (Google Earth Pro 2017).

Paratypes (156 specimens; EMEC, HNHM, MNHW, NHMW, QMB): see Suppl. material 2.

This species epithet is a patronym honoring Dr. René Jeannel, whose extensive body of literature dominates 20th Century carabidology. Dr. Jeannel’s early and perspicacious appreciation of Wegenerian historical biogeography was ground breaking in Entomology (Jeannel 1942), and we have yet to test fully the biogeographic hypotheses he proposed in his many contributions. More close to home, the necessity of examining the male genitalia to determine M. jeanneli versus its sister species, M. fleutiauxi, reiterates Dr. Jeannel’s pioneering research on the underlying homologies of insect genitalia (Jeannel 1955) and his extensive use of insect genitalia to diagnose species (e.g. Jeannel 1944).

This species is distributed in the southern end of Grand Terre, from Mt. Humboldt on the north to Forêt Nord on the south (Fig. 15), allopatric to the northerly range of its adelphotaxon, M. fleutiauxi. These beetles are known from any even greater altitudinal range than M. jeanneli, with recorded elevations ranging 160–1600 m. As with M. jeanneli, the vast majority (150 of 156 specimens) have been collected on tree trunks or downed logs, most via application of pyrethrin spray. A series of 31specimens was taken during one collecting event through spray application onto a moss-covered trunk (QMB). Thus, like M. jeanneli, this species is associated with emergent plant substrates, not the ground-level litter microhabitat.

These beetles (Fig. 16A) share an orbicular pronotum and smooth ovoid elytra with the previous two species, M. fleutiauxi and M. jeanneli (Fig. 9D–E). This similarity in body form is indicative of phylogenetic relationship, as M. plurisetosus comprises the adelphotaxon to those species two (Fig. 7). However this species can be diagnosed from all others by the presence of extra setae on the pronotum. In addition to the large setae homologized with the lateral pronotal setae, there are 9–11 smaller setae in the marginal depression anterad the lateral seta, and 4–5 setae in the depression behind the lateral seta. The prosternum also bears a sparse pelage of elongate setae, with the anterior surfaces of the femora also so covered. The elytral striae are totally reduced in this species, and the cuticular microsculpture also totally absent from head capsule, pronotum, elytra, and ventrites. Standardized body length 4.7–5.1 mm. Chaetotaxy +/+//2+11/–5//+/2/+/+, signifying that the lateral pronotal seta has been doubled, with up to 11 microsetae lining the lateral marginal depression anterad those setae. Also, though the basal pronotal seta is absent, up to 5 microsetae lie along the lateral margin near the pronotal base. The two lateral pronotal setae are longer and stouter than the anterior 11 and posterior 5 microsetae, supporting homology of the double setae with the single lateral pronotal seta of the other species, and the autapomorphic status of the numerous and variable microsetae.

Figure 16. 

New Caledonian Mecyclothorax (Phacothorax) spp., dorsal view: A, M. plurisetosus; B, M. megalovatulus; C, M. octavius; D, M. laterovatulus; E, M. najtae.

(n = 3). Head capsule trapezoidal, neck broad, with small, moderately convex eyes, ocular lobe meeting gena at obtuse angle very close to eye posterior margin; 18–19 ommatidia along horizontal diameter of eye; ocular ratio 1.28–1.42, ocular lobe ratio 0.88–0.91, EyL/EyD = 2.9–3.1; frontal grooves very deep, arcuately convergent at midlength, extended deeply onto clypeus; mandibles moderately elongate, mandibular ratio 1.8; ligular lateroanterior margin rounded to ligular seta, the two setae separated by one to two setal diameters; paraglossae thin, extended as far beyond ligular margin as half of basal length to margin; antennae very elongate, antennomere 9 length 3.4× maximal breadth; antennomere 3 with sparse fine setae near apex in addition to apical ring of longer setae. Pronotum transversely ovoid, median base depressed relative to disc, lateral margins evenly curved to meet narrow median peduncular collar, pronotal lateral margin obtusely concave at the juncture (Fig. 16A); MPW/BPW = 3.6–3.9, MPW/PL = 1.23–1.25; front angles protruded, obtusely rounded, the apex broad to match broad base of head, APW/BPW = 2.1–2.3; basal margin bordered by broadly convex marginal bead that joins lateral marginal bead at sinuate margin, three deep pits anterad median marginal bead; median longitudinal impression very finely incised on disc, terminated anteriorly at position of anterior transverse impression; anterior transverse impression very broad, very shallow, indistinctly traceable to front angles; proepisternum separated from prosternum by a narrow, shallow groove both anteriorly and ventrally; prosternum without anteapical impression, though anterior margin is irregularly punctate; prosternal process narrowly depressed between procoxae, that depression not extended anteriorly, but venter of prosternum is flattened toward front of prothorax (as in M. fleutiauxi and M. jeanneli). Elytra ovate, broadest in basal half and narrowed apically; MEW/EL = 0.81–0.85; basal groove very briefly extended laterad scutellum, the only indication of humeral angle being the basal groove’s juncture with the broader lateral marginal depression; striae 1–7 absent, only striae 8 and 9 (i.e. the inner portion of the elytral lateral marginal depression) present; only an obsolete vestige of the sutural stria evident at apex; elytra appressed and conjoined at apex where the sutural margin is narrowly and distinctly upraised. Pterothoracic mesepisternal anterior surface smooth except for a broad deep pit ventrally near prosternum; mesosternal-mesepisternal suture incomplete, obsolete to absent anteriorly (as in Fig. 3B); metepisternum foreshortened, maximum width/lateral length = 1.0; metepisternal-metepimeral suture incomplete, obsolete laterally. Abdomen with only a shallow crescent-shaped depression along suture between first and second ventrite, second ventrite little depressed posterad crescent; suture between second and third ventrites reduced though traceable laterally; ventrites 2–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons reduced, surface glossy; pronotal disc and base with shallow transverse mesh, sculpticell breadth 3–4× length; elytra glossy, only patchy indications of transverse microsculpture visible.

Male genitalia (n = 1). Antecostal margin of abdominal mediotergite IX angulate, an elongate “butterfly-net handle” extension distally (Fig. 17B); right paramere elongate, slightly convex dorsally near base, narrowly extended to apex (Fig. 18A), dorsal and ventral surfaces glabrous, two apical setae present; left paramere narrow basally, evenly constricted to a narrow, porrect apex, also glabrous except for two apical setae; aedeagal median love gracile, parallel-sided at midlength, the apex expanded dorsally to an acuminate point, and ventrally as a rounded projection (Fig. 17A); median lobe internal sac with evident crescent-shaped structure (Fig. 17A) homologous with flagellar sheath of above two species; folds of internal sac visible in the single uneverted type specimen interpreted as a bilobed sac as per the previous two species.

Figure 17. 

Male aedeagal median lobe and parameres, and ring sclerite–mediotergite plus antecostal margin, tergite IX–of Mecyclothorax (Phacothorax) spp.: A–B, M. plurisetosus, right view, dorsal view in situ (Aoupinié); C–D, M. megalovatulus, right view, dorsal view of righ sclerite (Mt. Panié); E–F, M. octavius, right view, dorsal view in situ (Me Maoya); G–H, M. laterovatulus, right view, dorsal view in situ (Aoupinié); I–J, M. manautei, right view, dorsal view in situ (Mt. Humboldt, 1400 m); K–L, M. paniensis, right view, dorsal view in situ (Mt. Panié); M–N, M. mouensis, right view, dorsal view in situ (Mt. Mou). See Table 2 for abbreviations.

Female reproductive tract (n = 1). Bursa copulatrix unilobate, elongate, length about 3× circumference, walls thin, slightly wrinkled (Fig. 12F); the only evidence of spermathecal configuration is a lightly sclerotized helminthoid sclerite near apex of bursa, spermatheca lost in single dissected female; basal gonocoxite 1 with apical fringe of 2 setae, lateral seta smaller, a few medial setae scattered along median margin (Fig. 13F); apical gonocoxite 2 moderately broad basally, breadth less than half of length; two lateral ensiform setae, apical seta much longer and broader than basal seta.

Types – Holotype male (MNHN): NEW CALEDONIA 8716 / 21°11’Sx165°18’E.850m / Aoupinie, top camp, / 2-3Nov2001.C.Burwell& / GMonteith.pyr.trees,logs // QUEENSLAND / MUSEUM LOAN / DATE: Nov. 2003 / No. LEN-1686 (green label) // New Caledonia Mecyclothorax revision / measured specimen 3 / J.K. Liebherr 2016 // HOLOTYPE / Mecyclothorax / plurisetosus / J.K.Liebherr 2017 (black-bordered red label).

Paratypes (2 specimens): same locality and labeling as holotype (QMB, 1); Aoupinié summit, 1000 m el. [984 m; Google Earth Pro 2017], 21°11’S 165°16’E, pyrethrum trees & logs, 02-x-2004, lot 11665, Monteith (QMB, 1).

The presence of accessory setae on the pronotal lateral margins (Fig. 16A), prosternum, legs, and ventral body surface supports application of the compound adjectival epithet plurisetosus.

This species is known only from the upper elevations of Mt. Aoupinié (Fig. 19), either from the vicinity of the summit transmitting station, or along the approach road at 850 m elevation. The four specimens were all collected via the application of pyrethrin spray to standing trees or downed logs. As this species is the adelphotaxon to M. fleutiauxi + M. jeanneli, finding it in this arboreal microhabitat supports the phylogenetic retention of preferred microhabitat among this triplet of species.

This and the following species, M. octavius, can be diagnosed by their large body size; in this species standardized body length = 5.4–5.8 mm. Individuals of this species have the elytral striae well developed, with striae 1–8 deep and continuous throughout their length (Fig. 16B) in contrast to the obsolete striae and smooth elytra of M. octavius (Fig. 16 C). The elytra are narrowly ellipsoid with very narrow humeri. The pronotal hind angles are obtuse but rounded at the apex of the angle, and the pronotal base is unmargined. Chaetotaxy +/+//+/–//+/2/+/+.

(n = 4). Head capsule trapezoidal, neck broad, eyes broad and little convex, ocular lobe meeting gena at very obtuse angle well behind eye posterior margin; 20 ommatidia along horizontal diameter of eye; ocular ratio 1.37–1.44, ocular lobe ratio 0.74–0.82, EyL/EyD = 2.81–2.86; frontal grooves narrow, well incised, sinuously convergent to just posterad clypeus, extended briefly onto clypeus; mandibles moderately elongate, mandibular ratio 1.83; ligular margin rounded to ligular seta, concave between the two setae, setae separated by one to two setal diameters; paraglossae thin, extended as far beyond ligular margin as half of basal length to margin; antennae elongate, antennomere 9 length 2.9× maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum vase-shaped, narrow basally, lateral margins only slight concave anterad rounded hind angles, median base convex, not depressed relative to disc, without marginal bead (Fig. 16B); MPW/BPW = 2.56–2.83, MPW/PL = 1.21–1.28; front angles protruded, obtuse, pronotal apex distinctly broader than base, APW/BPW = 1.65–1.74; median longitudinal impression shallowly and very finely incised on disc, intermittently extended in front of evident anterior transverse impression, terminated posteriorly in deep ellipsoid pit situated medially between the anterior margins of laterobasal depressions; anterior transverse impression broad and shallow but easily traceable to front angles; laterobasal depressions flat, triangular, defined medially by a longitudinal crease laterad median base and anteriorly by a transverse crease bordering pronotal disc; proepisternum separated from prosternum by a shallow groove both anteriorly and ventrally; prosternum with well-defined anteapical impression laterally, the impression shallower though complete ventrally; prosternal process shallowly and broadly depressed between procoxae, prosternum medially flattened anterad procoxae with an ovoid pitlike depression medially about 1/3 distance to anterior prosternal margin. Elytra ellipsoid, broadest about midlength, humeri distinctly sloping posterad humeral angle; MEW/EL = 0.74–0.81; basal groove briefly extended laterad scutellum, four-punctate at bases of abbreviated parascutellar striole, sutural and striae 3 and 4; intervals 3 and 8 more convex than the others at elytral apex, though all intervals are at least moderately convex; elytra appressed and conjoined at apex , sutural intervals slightly narrowed there. Pterothoracic mesepisternal anterior surface smooth except for a vertical furrow ventrally near prosternum; mesosternal-mesepisternal suture incomplete, obsolete to absent near anterior margin of mesothorax (as in Fig. 3B); metepisternum very short, maximum width/lateral length = 1.73, metepisternal-metepimeral suture incomplete, obsolete laterally. Abdomen with distinct, well-defined crescent-shaped depression along suture between first and second ventrite, second ventrite little depressed posterad crescent; suture between second and third ventrites reduced though traceable laterally; ventrites 2–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons and vertex a well-defined, transversely-stretched isodiametric mesh; pronotal disc and base with shallow transverse mesh, sculpticell breadth 3–4× length, surface glossy, sculpticells arranged as a distinct transverse mesh in laterobasal depressions; elytral disc with shallow transverse lines, the surface glossy, subiridescent, the apex covered with indistinct transverse lines.

Male genitalia (n = 1). Antecostal margin of abdominal mediotergite IX angulate, broad and little distended (Fig. 17D); right paramere with broad base, apex elongate, narrowly extended and membranous, with two very short apical setae (Fig. 18B); left paramere broad basally, evenly narrowed in basal half to an elongate whiplike extension, two elongate setae apically; aedeagal median lobe robust, broad dorsoventrally, distinctly curved both dorsally and ventrally to a subparallel, extended apex, the tip of apex laterally curved into an apical hooklike crease (Fig. 17C); aedeagal internal sac with flagellum, flagellar sheath, and dorsal plate (Fig. 17C).

Figure 18. 

Paired left (above) and right (below) parameres of Mecyclothorax (Phacothorax) spp. (ectal view): A, M. plurisetosus; B, M. megalovatulus; C, M. octavius; D, M. laterovatulus; E, M. manautei; F, M. paniensis; G, M. mouensis.

Female reproductive tract (n = 1). Bursa copulatrix elongate, length more than twice basal circumference, apical portion expanded laterally toward right, surface thick apically, wrinkled, densely stained relative to bursal base (Fig. 12G); spermathecal duct entering near bursa-common oviduct juncture with duct oriented toward right side of bursa, duct as long as spermathecal reservoir; a heavily sclerotized, triangular helminthoid sclerite present near base of spermathecal duct; spermatheca fusiform on narrow duct, spermathecal gland duct entering at base of spermathecal reservoir; ligular apophysis present near base of common oviduct; basal gonocoxite 1 with apical fringe of three setae situated near apicomedial angle, medial surface of gonocoxite 1 glabrous (Fig. 13G); gonocoxite 2 narrow basally, basal width about 2/3 medial length; two very gracile lateral ensiform setae present.

Types – Holotype male (MNHN): NEW CALEDONIA 8764 / 20°34’Sx164°46’E / Mt Panie refuge, 1300 m / 8-9Nov.2001.C.Burwell / Pyrethrum, trees & logs // QUEENSLAND / MUSEUM LOAN / DATE: Sept 2002 No. LE 02.43 (green label) // New Caledonia Mecyclothorax revision / measured specimen 3 / J.K. Liebherr 2016 ♂1 // genitalia in polyethylene vial with glycerine // HOLOTYPE / Mecyclothorax / megalovatulus / J.K.Liebherr 2017 (black-bordered red label).

Paratypes (3 specimens). NEW CALEDONIA: Mt. Panié, 1300-1600 m el., 20°35’S 164°46’E, 15-v-1984, Monteith & Cook (QMB, 1), refuge, 1300 m el., summit, 1600 m el., 20°34’S 164°46’E, rainforest, sieved litter, 9-xi-2001 lot 8769, Burwell (QMB, 1), track, 1500 m el., 20°34’S 164°46’E, pyrethrum trees & logs, 09-xi-2001, lot 8768, Burwell (QMB, 1).

Large body size and ovoid pronotum and elytra (Fig. 16B) suggested the compound adjectival epithet megalovatulus.

This species is only known from 1300–1600 m elevation on Mt. Panié, in the northern portion of the Chaîne Centrale (Fig. 19). Three of the six specimens have been recovered from sieved litter, whereas one was collected via pyrethrin spray application to trees and logs, supporting occupation of ground-level litter as well as plant-based, mossy microhabitats.

Figure 19. 

Geographical distributions of Mecyclothorax (Phacothorax) spp.

This species (Fig. 16C) exhibits superficial similarity to M. fleutiauxi and M. jeanneli (Fig. 9D–E), but differs in: 1, larger body size, standardized body length 5.8 mm; 2, presence of both anterior and posterior supraorbital setae; 3, an unmargined and depressed pronotal median base with sinuate lateral margins anterad the obtusely rounded hind angles; and 4, eyes of very small diameter, i.e. ocular lobe ratio = 0.71 versus ratios of 0.89–0.94 for individuals of the former two species. The male aedeagus is completely different, exhibiting a flagellum and flagellar sheath, and a dorsoventrally expanded apex (Fig. 17E). Chaetotaxy +/+//+/–//+/2/+/+.

(n = 1). Head capsule elongate, distinctly broader at the small, moderately convex eyes, ocular lobe gradually curving to meet gena well behind eye posterior margin; 20 ommatidia along horizontal diameter of eye; ocular ratio 1.45, ocular lobe ratio 0.71, EyL/EyD = 2.4; frontal grooves deep, sinuously convergent to just posterad clypeus, extended deeply onto clypeus; mandibles moderately elongate, mandibular ratio 1.8; ligular lateroanterior margin rounded to ligular seta, the two setae separated by one to two setal diameters; paraglossae thin, extended twice as far beyond ligular margin as their basal length to margin, apex observably spiculate (100×); antennae elongate, antennomere 9 length 2.3× maximal breadth; antennomere 3 with glabrous except for apical ring of setae. Pronotum transverse, vase-shaped, median base depressed relative to broadly convex disc, lateral margins evenly curved until joined to long median peduncular collar, pronotal lateral margin obtusely concave at the juncture (Fig. 16C); MPW/BPW = 2.4, MPW/PL = 1.1; front angles narrowly protruded, obtuse, pronotal apex constricted, APW/BPW = 1.35; median base trapezoidally depressed relative to convex disc, 8–10 small punctures present each side, lateral marginal bead continued along anterior half of basal peduncle, terminated at base of peduncle, median base unmargined posteriorly; median longitudinal impression very finely incised on disc, extended briefly anterad broad and shallow anterior transverse impression; anterior transverse impression very broad, very shallow, indistinctly traceable to front angles; proepisternum separated from prosternum by a deep, sinuous groove both anteriorly and ventrally; prosternum with anteapical impression that is continuous ventrally; prosternal process narrowly and deeply depressed between procoxae, depression extended anteriorly half the distance to prothoracic anterior margin, the depression broadest at anterior terminus. Elytra ellipsoid, broadest just anterad midlength; MEW/EL = 0.72; basal groove absent from very narrowly pedunculate elytral base, the very narrow lateral marginal depressions converging on posterior margin of pronotum; striae 1–7 very shallow though traceable , stria 8 deep, diverging from stria 9 just posterad anterior series of lateral elytral setae; all striae except 8 absent from elytral apex; apical elytral setae positioned only slightly nearer to suture than subapical seta; elytra appressed and conjoined at apex, the upraised sutural margin forming an elongate isosceles triangle connected to the narrowly beaded elytral apical margin. Pterothoracic mesepisternal anterior surface with eight broad punctures, the largest anterior puncture separated from the remainder by a vertical ridge; mesosternal-mesepisternal suture incomplete, obsolete to absent anteriorly (as in Fig. 3B); metepisternum very short, maximum width/lateral length = 1.46 (difficult to measure due to fusion of metepisternum and metepimeron). Abdomen with first and second ventrites fused laterally, not suture visible; suture between second and third ventrites reduced though traceable laterally; ventrites 2–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons reduced, an indistinct transverse mesh on a glossy surface, microsculpture on vertex an evident transverse mesh with some isodiametric sculpticells; pronotal disc and base with fine, elongate transverse mesh, sculpticell breadth 3–4× length, surface iridescent; elytra with evident transverse mesh, sculpticell breadth 2–3×length; elytral apex with elongate transverse mesh, sculpticell breadth 3–4× length where traceable.

Male genitalia (n = 1). Antecostal margin of abdominal mediotergite IX angulate, not extended (Fig. 17F); right paramere elongate, slightly expanded dorsally in basal half, narrowly extended apically (Fig. 18C), with 13 setae along the apical 2/3 of the ventral margin, those setae complementing two elongate apical setae; left paramere moderately broad basally, evenly narrowed to a moderately extended, narrow apex, two small setae present apically; aedeagal median lobe gracile, tubular, straight at midlength, with apex broadly expanded dorsoventrally, dorsally to am obtuse point, ventrally in a tightly rounded and projected margin; aedeagal median lobe internal sac with flagellum and flagellar sheath, apparently unilobate based on interpretation of uneverted unique type male (Fig. 17E), a diffuse spicular patch apicad flagellar apparatus, no structure present at position of dorsal plate.

Type –Holotype male (MNHN): NEW CALEDONIA / Me Maoya, summit / plateau.12Nov2002. / Monteith & Burwell // QM Berlesate 1080 / 21°22’Sx165°20’E / rainforest, 1400 m/ / sieved litter // QUEENSLAND / MUSEUM LOAN / DATE: Nov. 2003 / No. LEN-1686 (green label) // New Caledonia Mecyclothorax revision / measured specimen 1 / J.K. Liebherr 2016 ♂1 // genitalia in polyethylene vial with glycerine // HOLOTYPE / Mecyclothorax / megalovatulus / J.K.Liebherr 2017 (black-bordered red label) .

Given that the body form comprises a pair of ovoids (Fig. 16C) suggesting the numeral eight, this species is given the epithet octavius. As a Latin personal name, denoting the eighth-born son, or a son born in the eighth month, the species name is to be treated as a noun.

The single specimen of this species was collected from sieved litter collected at the 1400 m summit of Mt. Maoya (Fig. 19). This species is adelphotaxon to the species triplet M. plurisetosus (M. fleutiauxi + M. jeanneli), all of whom are most commonly found in arboreal microhabitats, supporting transformation of habitat preference to the arboreal realm in their common ancestor.

This and the following species M. najtae (Fig. 16D–E) are characterized by very obtuse pronotal hind angles that are rounded apically, pronotal lateral margins straight to only indistinctly concave before the very obtuse angles. The elytra are broader basally in beetles of this species, with the humeri extended anterad and the basal groove narrowly rounded near the base of stria 6, and elytral length is relatively longer than in M. najtae, with MEW/EL = 0.85. The outer elytral striae 5–7 are well impressed at midlength in this species, versus obsolete to entire absent laterally in M. najtae. The configuration of the male aedeagal internal sac–with elongate, curved flagellum and flagellar sheath and a dorsal plate (Fig. 17G) – indicates this species’ true relatives (Fig. 7); M. laterorectus (Fig. 10F) and M. laterosinuatus (Fig. 10C–D). Chaetotaxy +/+//+/–//+/2/+/+.

Standardized body length 4.1 mm.

(n = 1). Head capsule broad, foreshortened, eyes small, moderately convex, ocular lobe meeting gena at very obtuse angle; 15–16 ommatidia along horizontal diameter of eye; ocular ratio 1.39, ocular lobe ratio 0.89, EyL/EyD = 3.13; frontal grooves nearly straight from posterior terminus inside anterior supraorbital seta to deepest point just posterad clypeus, briefly and shallowly extended onto clypeus; mandibles moderately elongate, mandibular ratio 1.8; ligular anterior margin narrowly rounded to ligular seta, concave between setae, the two setae separated by one to two setal diameters; paraglossae thin, extended as far beyond ligular margin as their basal length to margin; antennae elongate, antennomere 9 length 2.5× maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum vase-shaped, hind angles broadly subangulate, lateral margins only slightly concave anterad angles (Fig. 16D); MPW/BPW = 1.66, MPW/PL = 1.24; front angles only slightly protruded, broadly obtuse, APW/BPW = 0.93; median base coplanar relative to disc, unmargined; laterobasal depression with longitudinal tubercle inside hind angle, defined medially by longitudinal border with median base; median longitudinal impression fine and shallow on disc, posteriorly terminated at deep lenticular pit anterad median base, terminated anteriorly at very broad and shallow anterior transverse impression; proepisternum separated anteriorly from prosternum by fine shallow groove, distinctly separated ventrally by smooth, deep groove; prosternal process deeply, narrowly depressed between procoxae, that depression extended 1/4 distance toward anterior prothoracic margin. Elytra broadly ellipsoid to hemiovoid, humeri extended laterally, humeral angle rounded outside pronotal hind angles; MEW/EL = 0.85; basal groove extended anterad from scutellum to humerus, with depressions at bases of sutural and elytral striae 4–5; sutural stria deep throughout length, striae 2 and 5–7 almost as well developed, striae 3–4 shallower though still evident; striae 1–2 and 7 evident apically, elytra appressed and conjoined apically, sutural intervals narrower and upraised at apex. Pterothoracic mesepisternal anterior furrow with five pitlike depressions in one vertical row; metepisternum maximum width/lateral length = 0.88; mesosternal-mesepisternal suture complete (as in Fig. 3A); metepisternal-metepimeral suture incomplete, shallower and incomplete laterally. Abdomen with deep crescent-shaped depression along suture between first and second ventrite, second ventrite depressed within crescent; suture between second and third ventrites reduced, incomplete laterally; ventrites 2–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons and vertex an evident transversely stretched isodiametric mesh; pronotal disc and base covered with elongate transverse mesh, sculpticell breadth 3–4× length, surface iridescent, sculpticells in laterobasal depressions less transverse, breadth 2–3× length; elytra iridescent, disc with dense transverse lines loosely connected into a mesh, apex covered with transverse lines. Femora rufobrunneous, a piceous cloud in basal 2/3.

Male genitalia (n = 1). Antecostal margin of abdominal mediotergite IX angulate, not extended (Fig. 17H); right paramere narrow, narrowly extended apically (Fig. 18D), with two setae on the ventral margin complementing a single apical seta; left paramere narrow basally, extended as an elongate, whiplike extension with a single apical seta; aedeagal median lobe robust, broad dorsoventrally, apex evenly narrowed dorsally and ventrally to a narrowed rounded tip (Fig. 17G); aedeagal median lobe internal sac with dorsal plate, dorsally curved flagellum and flagellar sheath.

Type – Holotype male (MNHN): NEW CALEDONIA 11665 / 21°11’S 165°16’E. / Aoupinie, summit. 1000 m / 2Oct2004. G.Monteith / pyrethrum, trees&logs // QUEENSLAND / MUSEUM LOAN / DATE: July 2005 / No. LE 05.24 // New Caledonia Mecyclothorax revision / measured specimen 1 / J.K. Liebherr 2016 ♂1 // genitalia in polyethylene vial with glycerine // HOLOTYPE / Mecyclothorax / laterovatulus / J.K.Liebherr 2017 (black-bordered red label) /

Though this species is separated in the dichotomous key and therefore in the species treatment sequence from its broad-bodied phylogenetic relatives (Fig. 9AC), this species is given the compound adjectival epithet laterovatulus to signify the broad body and ovoid pronotum coupled with rounded pronotal hind angles (Fig. 16D), thereby making the species name reiterate the names of those other species; M. laterobustus, M. laterorectus, and M. laterosinuatus.

The lone holotype of this species was collected on Aoupinié summit at 1000 m elevation via application of pyrethrin spray to trees and logs (Fig. 19). Based on restriction of its adelphotaxon, M. laterorectus + M. laterosinuatus, as well as the closely related M. laterorobustus (Fig. 7) to ground-level microhabitats, it is predicted that additional specimens of this species will be collected predominantly in ground level litter, or from mossy subcortical microhabitats.

This, the second of the small-bodied species with very obtuse pronotal hind angles and basally straight lateral pronotal margins (Fig. 16D–E) can be diagnosed by the unique elytral configuration with elytral length only slightly greater than breadth: MEW/EL = 0.96. This species is also characterized by extremely convex eyes, with the eye convexity ratio, EyL/EyD = 2.0. Standardized body length 3.7 mm. Chaetotaxy +/+//+/–//+/2/+/+.

(n = 1). As a complement to Deuve’s (1987) description, we may add: 14 ommatidia along horizontal diameter of eye; ligular apex rounded, the two ligular setae separated by two setal diameters; paraglossae thin, extended beyond ligular margin 1/2 distance from their base to ligular margin; antennae moderately elongate, antennomere 9 length 2.25× maximal breadth. Pronotum transverse, hind angles very obtuse, the lateral margins only slightly concave anterad angles (Fig. 16E); MPW/BPW = 2.0, MPW/PL = 1.32; front angles only slightly protruded, broadly obtuse, pronotal apex and base subequal, APW/BPW = 1.05; proepisternum separated anteriorly from prosternum by fine shallow groove, distinctly separated ventrally by deep, indistinctly punctate groove; prosternal process deeply depressed between procoxae, that depression extended 1/2 distance toward anterior prothoracic margin. Abdomen with deep crescent-shaped depression along suture between first and second ventrite, second ventrite depressed within crescent; suture between second and third ventrites reduced, incomplete laterally; ventrites 2–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons and vertex a shallow transversely stretched isodiametric mesh; pronotal disc covered with elongate transverse mesh, sculpticell breadth 2–3× length, surface subiridescent, sculpticells on median base and in laterobasal depressions less transverse, breadth 2× length; elytra iridescent, disc with dense transverse lines loosely connected into a mesh, apex covered with transverse lines.

Type – Holotype female (MNHN): HOLOTYPE (red label) // Nouvelle-Caledonie / Menazi 1020 m / 18.x84 Tillier”/”Bouchet // Mecyclothorax / najtae sp. n. / det. T. Deuve // New Caledonia Mecyclothorax revision / measured specimen 1 / J.K. Liebherr 2016. The specimen is mounted on two platens: 1, head, prothorax, and pterothorax separated from elytra; 2, abdominal ventrites. No female genitalic structures were available for study in this specimen.

The type locality northwest of the summit of Menazi (Fig. 19) is situated at 21°26.83’S × 165°41.75’E. Deuve (1987) reported the microhabitat as humid Auracaria forest on peridotite; i.e. igneous, ultramafic rock.

This species can be diagnosed by small body size–standardized body length 3.5–3.9 mm–and the transversely ovoid pronotum with evenly convex lateral margins basally, i.e., hind angles lacking (Fig. 20A). The elytral striae are much more reduced than in the prior two species–M. laterovatulus and M. najtae–with the sutural stria obsolete at midlength, and only striae 2–3 evident there, though very shallow. The eyes broadly cover the ocular lobe, ocular lobe ratio 0.88–0.89, and are very convex, i.e. “popeyed”, with EyL/EyD = 2.2–2.4. Chaetotaxy +/+//+/–//+/2/+/+.

Figure 20. 

New Caledonian Mecyclothorax (Phacothorax) spp., dorsal view: A, M. manautei; B, M. paniensis; C, M. mouensis; D, M. kanak (Mt. Humboldt, 580 m); E, M. kanak (Mt. Humboldt, 630 m); F, M. kanak (Mt. Dzumac); G, M. kanak (Col de Yaté); H, M. picdupinsensis.

(n = 4). Head capsule quadrate, eyes very convex, popeyed, ocular lobe meeting gena at obtuse angle close to eye posterior margin; 14 ommatidia along horizontal diameter of eye; ocular ratio 1.48–1.52, ocular lobe ratio 0.88–0.89, EyL/EyD = 2.2–2.4; frontal grooves deep, slightly convergent to deepest portion just posterad clypeus, deeply extended onto clypeus; mandibles elongate, mandibular ratio 1.92; ligular anterior margin rounded to ligular seta, concave between setae, the two setae separated by one to two setal diameters; paraglossae thin, extended twice as far beyond ligular margin as their basal length to margin; antennae elongate, antennomere 9 length 2.25× maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum transversely ovoid, lateral margin evenly convex anterad base, hind angles absent though suggested by presence of short peduncular collar at base of pronotum (Fig. 20A), MPW/BPW = 2.46–2.55, MPW/PL = 1.29–1.31; front angles slightly protruded, obtuse-rounded, APW/BPW = 1.39–1.48; median base unmargined basally, trapezoidally depressed relative to disc, the median longitudinal impression divided basally into two transverse impressions that isolate disc from base, each transverse basal impression terminated laterally in pitlike laterobasal depression; median longitudinal impression finely incised on disc, terminated anteriorly just anterad anterior transverse impression, a lenticular fovea at posterior juncture with basal transverse impressions; anterior transverse impression shallow, broad, but traceable to front angles; proepisternum separated from prosternum by a distinct groove both anteriorly and ventrally; smooth anteapical impression well developed laterally, continuous though shallower ventrally; prosternal process deeply and broadly depressed between procoxae, that depression extended 2/3 distance toward anterior prothoracic margin, the depression broadest at its anterior terminus. Elytra broadly ovoid, humeri sloped posteriorly laterad scutellum, humeral angle indicated only by slight change in curvature at juncture of narrow basal elytral groove and broader lateral marginal depression; MEW/EL = 0.79–0.94; all striae reduced on disc, stria 3 and 6 more evident, but intervening intervals at most slightly convex; only stria 8 evident apically, stria 2 present as very broad and shallow depression; elytra appressed and conjoined apically, the suture upraised at apex. Pterothoracic mesepisternal anterior furrow with 5 punctures in a curved line; mesosternal-mesepisternal suture complete (as in Fig. 3A); metepisternum maximum width/lateral length = 1.08; metepisternal-metepimeral suture complete. Abdomen with broad crescent-shaped depression along suture between first and second ventrite, second ventrite only slightly depressed within crescent; suture between second and third ventrites reduced though traceable laterally; ventrites 2–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons reduced, surface glossy, indistinct transversely stretched sculpticells evident on vertex; pronotal disc glossy, transverse-line microsculpture visible over portions of surface depending on direction of light reflection, trapezoidal median base with only indistinct indications of transverse microsculpture; elytra iridescent, disc with elongate transverse mesh mixed with transverse lines, elytral apex covered with elongate transverse-mesh microsculpture.

Male genitalia (n = 1). Antecostal margin of abdominal mediotergite IX broadly angulate, not extended (Fig. 17J); right paramere narrow basally, evenly narrowed to apex, with 5 setae along ventral margin and two short apical setae (Fig. 18E); left paramere broad basally, narrowed to a dorsally twisted apex, parameral apex flexibly articulating with base, two elongate apical setae present; aedeagal median lobe robust, broad dorsoventrally, with apex distinctly down-curved relative to the expanded shaft and flattened into an apical face (Fig. 17I); male aedeagal internal sac with short flagellum and flagellar sheath present, a dorsal plate dorsad and basad flagellar complex, and a large dorsoapical field of macrospicules.

Female reproductive tract (n = 1). Bursa copulatrix length slightly greater than circumference, its surface thin, translucent, only slightly wrinkled (Fig. 23A); spermathecal duct entering near bursa-common oviduct juncture with duct oriented toward right side of bursa, duct length about 1.25× length of spermathecal reservoir; laminar helminthoid sclerite with rounded apex present at base of spermathecal duct; spermatheca fusiform on narrow duct, spermathecal gland duct entering at base of spermathecal reservoir; ligular apophysis present near base of common oviduct; basal gonocoxite 1 with apical fringe of two setae laterally–a smaller seta may be present medially–and several small setae near apex of medial margin (Fig. 24A); gonocoxite 2 moderately broad basally, basal width 0.6× medial length; two gracile lateral ensiform setae of moderate length present.

Types – Holotype male (MNHN): NEW CALEDONIA 11138 / 21°53’SX166°24’E.1400m. / Mt Humboldt, moss forest. / 6-7Nov2002. Monteith & / Burwell.pyreth,trees&logs // QUEENSLAND / MUSEUM LOAN / DATE: Nov. 2003 / No. LEN-1686 (green label) // New Caledonia Mecyclothorax revision / measured specimen 1 / J.K. Liebherr 2016 // HOLOTYPE / Mecyclothorax / manautei / J.K.Liebherr 2017 (black-bordered red label).

Paratypes (3 specimens). NEW CALEDONIA: Mt. Humboldt, moss forest, 1400 m el., 21°53’S 166°24’E, pyrethrum trees & logs, 06-07-xi-2002, lot 11138, Monteith/Burwell (QMB, 2), beyond summit, 1500 m el., 21°53’S 166°25’E, 07-xi-2002, lot 11122, Burwell (QMB, 1).

This species epithet is a patronym honoring Joseph Manauté, Directeur du Parc Provincial de la Rivière Bleue chez Province Sud, who provided helicopter support for the Queensland Museum expedition to Mt. Humboldt, allowing Geoff Monteith and Chris Burwell to collect the type series of this species as well as other interesting and important taxa (Reid and Smith 2004).

The species is known only from elevations 1400–1500 on Mt. Humboldt (Fig. 25). The four specimens were all collected via application of pyrethrin spray to tree trunks and downed logs.

These beetles can be diagnosed by the parallel lateral margins at the base of the pronotum, resulting in very slightly obtuse hind angles that protrude laterally (Fig. 20B). The elytral striae are much reduced, with the sutural striae only evident basally where it comprises a series of shallow, disconnected, elongate depressions. The elytra are broadly ovoid, with the humeri very reduced, with the elytral basal groove angulate posterad the protruded pronotal hind angles. Standardized body length 3.5–4.1 mm. Chaetotaxy +/+//+/–//+/2/+/+.

(n = 5). Head capsule elongate, eyes small, convex, ocular lobe-genal juncture evenly curved, a very shallow groove indicating limit of ocular lobe; 14 ommatidia along horizontal diameter of eye; ocular ratio 1.35–1.42, ocular lobe ratio 0.77–0.82, EyL/EyD = 2.0–2.49; frontal grooves narrowly incised, straight and convergent to deepest portion at frontoclypeal suture, deeply extended onto clypeus; mandibles moderately elongate, mandibular ratio 1.71; ligular anterior margin narrowly rounded, the two ligular setae separated by one to two setal diameters; paraglossae thin, extended twice as far beyond ligular margin as their basal length to margin; antennae elongate, antennomere 9 length 2.62× maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum distinctly cordate, lateral margins slightly convergent anterad protruded, obtusely-angulate hind angles, the lateral margin immediately divergent anterad subparallel lateral margins at pronotal base (Fig. 20B), MPW/BPW = 1.83–1.88, MPW/PL = 1.13–1.26; front angles slightly protruded, obtuse, APW/BPW = 1.11–1.16; median base unmargined basally, trapezoidally depressed relative to disc, the median longitudinal impression divided basally into two transverse impressions that isolate disc from base, each transverse basal impression terminated laterally in a longitudinally arcuate laterobasal depression; median longitudinal impression finely incised on disc, terminated anteriorly just anterad anterior transverse impression, a lenticular fovea at posterior juncture with basal transverse impressions; anterior transverse impression shallow, broad, intermittently traceable to front angles; proepisternum separated from prosternum by a shallow groove anteriorly, and deep, distinct groove ventrally; smooth anteapical impression well developed laterally, continuous though shallower ventrally; prosternal process broadly depressed between procoxae, that depression extended 1/2 distance toward anterior prothoracic margin, the depression broadest at its anterior terminus. Elytra broadly ovoid, humeri extended laterally before sloping posteriorly laterad distinct, obtuse humeral angle; MEW/EL = 0.80–0.88; all striae reduced on disc, sutural and fourth stria most evident, but intervening intervals flat; sutural stria distinctly impressed apically to complement deep stria 8; elytra appressed and conjoined apically, the sutural margin upraised at apex. Pterothoracic mesepisternal anterior furrow with 2–3 irregular pits in deepest portion of furrow; mesosternal-mesepisternal suture complete (as in Fig. 3A); metepisternum slightly longer than broad, maximum width/lateral length = 0.92; metepisternal-metepimeral suture complete. Abdomen with broad crescent-shaped depression along suture between first and second ventrite, second ventrite only slightly depressed within crescent; suture between second and third ventrites reduced though traceable laterally; ventrites 2–6 with broad, shallow, linear to circular plaques near lateral margin. Microsculpture of frons reduced, surface glossy, indistinct transverse mesh visible over portions of vertex; pronotal disc glossy but with transverse sculpticells, breadth 4× length, and transverse lines over surface, trapezoidal median base with transverse sculpticells, breadth 3× length visible in areas of no reflection; elytra distinctly iridescent, disc covered with transverse lines, elytral apex covered with elongate transverse sculpticells and lines.

Male genitalia (n = 1). Antecostal margin broadly angulate, not extended (Fig. 17L); right paramere narrow basally, apical half narrowed into a narrow whiplike extension, its ventral surface bearing 15 setae near midlength distant from elongate pair of apical setae (Fig. 18F); left paramere narrow basally, evenly narrowed to a whiplike apex, two apical setae present; aedeagal median lobe robust, broad dorsoventrally, the ventral and dorsal margins evenly curved to a broadly rounded apex that extends moderately beyond ostial opening (Fig. 17K); aedeagal median lobe internal sac with elongate flagellum and flagellar sheath plus dorsal plate.

Female reproductive tract (n = 1). Bursa copulatrix length slightly greater than circumference, its surface thin, translucent, not wrinkled (Fig. 23B); spermathecal duct entering near bursa-common oviduct juncture with duct oriented toward right side of bursa, duct length twice length of spermathecal reservoir; knoblike helminthoid sclerite present at base of spermathecal duct; spermatheca fusiform on narrow duct, spermathecal gland duct entering at base of spermathecal reservoir; ligular apophysis present on common oviduct; basal gonocoxite 1 with apical fringe of two setae laterally and several smaller setae medially, a series of small setae lining medial margin (Fig. 24B); gonocoxite 2 moderately broad basally, basal width half medial length; two gracile lateral ensiform setae of moderate length present, the apical seta slightly broader.

Types – Holotype male (MNHN): NEW CALEDONIA / Mt Panie summit / Nov 2001 / C. Burwell // QM Berlesate 1058 / 20°34’Sx164°46’E / Rainforest, 1600m / Sieved litter // QUEENSLAND / MUSEUM LOAN / DATE: Sept 2002 No. LE 02.43 (green label) // HOLOTYPE / Mecyclothorax / paniensis / J.K.Liebherr 2017 (black-bordered red label).

Paratypes (11 specimens). NEW CALEDONIA: Mt. Panié, 20°34’S 164°46’E, 08-x-1977, J. Balogh (HNHM, 1), 1300-1600 m, 15-v-1984, Monteith & Cook (QMB, 1), E trail, 1350–1629 m el., 20°35.3’S 164°46.2’E, rainforest, 24-xi-2010, Wanat & Ruta (MNHW, 3), refuge, 1300 m el., 20°34’S 164°46’E, rainforest, sieved litter, 8–9–xi–2001, lot 1056, Burwell (QMB, 2), summit, 1600 m el., 20°34’S 164°46’E, rainforest, sieved litter, xi-2001, lot 1058, Burwell (QMB, 2), summit, 1600, 20°35’S 164°46’E, 18-xi-2000, 9939, Bouchard, Burwell & Monteith (QMB, 2).

The adjectival ending -ensis is elided with the type locality Mt. Panié to obtain the species epithet paniensis, an adjective in the genitive case.

This species’ distribution is restricted to Mt. Panié (Fig. 25). Collecting localities are in the higher reaches of the mountain, 1300–1629 m elevation, with recorded microhabitats or collecting situations including rainforest and sieved litter. As such it appears beetles of this species occupy the ground-level litter layer.

This species, along with M. kanak and M. picdupinsensis, comprises a triplet of cryptic sibling species best determined using the male aedeagal median lobe. To that end, this species is characterized by a median lobe with the apex dorsally and ventrally subparallel beyond the ostial opening, and with the lobe’s apical face narrowly flattened (Fig. 17M). All three species share broadly hemiovoid elytra, with this species exhibiting a broadly rounded basal groove across the humerus. Individuals of this species can be best diagnosed externally from those of the following two species by the broader elytral lateral marginal depression outside the anterior series of lateral elytral setae (Fig. 20C). The anterior lateral elytral setae are situated in the lateral depression in beetles of this species, whereas they lie on the upraised lateral reaches of the elytral disc in M. kanak and M. picdupinsensis. Also the sutural stria is deep and smooth on the disc and striae 2–3 are evident and traceable to nearly obsolete in M. mouensis. This differs from the sutural stria in beetles of the following two species where the sutural stria is crenulate to indistinctly punctate on the disc. Standardized body length 2.8–3.4 mm. Chaetotaxy +/+//+/–//+/2/+/+.

(n = 5). Head capsule elongate, eyes small, very convex, ocular lobe-genal juncture evenly curved, a very shallow groove indicating limit of ocular lobe; 11 ommatidia along horizontal diameter of eye; ocular ratio 1.43–1.48, ocular lobe ratio 0.73–0.77, EyL/EyD = 2.17–2.38; frontal grooves narrowly incised, sinuously convergent to pit at frontoclypeal suture, briefly extended onto clypeus; mandibles moderately elongate, mandibular ratio 1.73; ligula narrowed to a moderately broad, slightly convex anterior margin, the two ligular setae separated by one setal diameter; paraglossae thin, extended twice as far beyond ligular margin as their basal length to margin, apex visibly spiculate (100×); antennae moderately elongate, antennomere 9 length 2.0× maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum very transverse, distinctly cordate, lateral margins sinuately concave anterad obtuse-rounded hind angles (Figs 2B, 20C), MPW/BPW = 2.43–2.82, MPW/PL = 1.35–1.39; front angles slightly protruded, obtuse, APW/BPW = 1.42–1.50; median base unmargined basally, trapezoidally depressed relative to disc, the median longitudinal impression divided basally into two transverse impressions that isolate disc from base, each transverse basal impression terminated laterally in a short laterally arcuate laterobasal depression; median longitudinal impression finely incised on disc, terminated anteriorly at anterior transverse impression, a narrow fovea at posterior juncture with basal transverse impressions; anterior transverse impression shallow, broad, traceable to front angles; proepisternum separated from prosternum by a shallow groove anteriorly, and deep, distinct groove ventrally; smooth anteapical impression well developed laterally, continuous though shallower ventrally; prosternal process broadly, shallowly depressed between procoxae, the shallow depression extended 1/2 distance toward anterior prothoracic margin. Elytra broadly hemiovoid, humeri well-extended laterally before lateral margins curve posteriorly; basal elytral groove posteriorly curved laterad obtuse humeral angle; MEW/EL = 0.85–0.91; sutural stria well developed in basal 2/3, striae 2–3 traceable on disc near positions of dorsal elytral setae, stria 4 indicated by an series of intermittent longitudinal depressions; only stria 8 evident on elytral apex; elytra appressed and conjoined apically, the sutural margin upraised at apex. Pterothoracic mesepisternal anterior furrow with five to six depressions in one to two irregular rows; mesosternal-mesepisternal suture complete (as in Fig. 3a); metepisternum length and breadth subequal; metepisternal-metepimeral suture complete though fine laterally. Abdomen with elongate crescent-shaped depression along suture between first and second ventrite, second ventrite only slightly depressed within crescent; suture between second and third ventrites reduced though traceable laterally; ventrites 3–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons reduced, surface glossy, indistinct transverse mesh–sculpticell breadth 2× length–visible over portions of vertex; pronotal disc glossy but with transverse sculpticells visible outside areas of reflection, trapezoidal median base glossy with indistinct transverse mesh anterad laterobasal depression; elytra opalescent, disc covered with very finely separated transverse lines, elytral apex covered with elongate transverse sculpticells and lines.

Male genitalia (n = 8). Antecostal margin of mediotergite IX angulate, not extended (Fig. 17N); right paramere narrow, with basal cuff articulating with elongate, whiplike apical extension (Fig. 18G), six setae along ventral margin to complement to longer apical setae; left paramere narrow basally, evenly narrowed to whiplike apex; aedeagal median lobe robust, broadest medially basad apex of ostial opening, apex subparallel dorsoventrally beyond ostium, with apical face somewhat flattened (Fig. 17M); aedeagal median lobe internal sac with broad, basal dorsal plate and a large field of macrospicules apicad the plate, but flagellum and flagellar sheath not present.

Female reproductive tract (n = 1). Bursa copulatrix length subequal to circumference, its surface thin, translucent, slightly wrinkled (Fig. 23C); spermathecal duct entering near bursa-common oviduct juncture with duct oriented toward right side of bursa; elongate laminar helminthoid sclerite present at base of spermathecal duct; spermatheca of only slightly greater circumference than spermathecal duct, spermathecal gland duct entering at base of spermathecal reservoir; ligular apophysis present on common oviduct; basal gonocoxite 1 with apical fringe of two setae laterally, a very small setae may be present immediately mesad, and several smaller setae along medial margin (Fig. 24C); medial margin bearing a dense field of microtrichia basally, this field about 3–4 microtrichia broad and appearing like the hooklike surface of a Velcro® closure; gonocoxite 2 moderately broad basally, basal width 0.6× medial length; two gracile lateral ensiform setae of moderate length present.

Types – Holotype male (MNHN): NEW CALEDONIA / Mt Mou summit / 24 May 1984 / G. Monteith & D. Cook // Q.M. Berlesate 659 / 22.04S X 166.21E / Rainforest, 1200 n / Litter // QUEENSLAND / MUSEUM LOAN / DATE: Nov. 2003 / No. LEN-1686 (green label) // HOLOTYPE / Mecyclothorax / mouensis / B.P. Moore & J.K. / Liebherr 2017 (black-bordered red label).

Paratypes (33 specimens). NEW CALEDONIA: Mts. Koghis, [code PA 58], 22°11’S 166°31’E, 30-viii-1970, Franz (NHMW, 3), ~5 km N Noumea, 550 m el., 22 10.5’S, 166 30.3’E, forest litter, 25-xi-2009, Schuh (NHMW, 1), forest, 520 m el., 22°10.7’S 166°30.3’E, sifted litter, 25-x-2008, Wanat (MNHW, 9), La Roussette, 600 m el., 22°10.8’S 166°30.7’E, sifted litter, 27-x-2008, Wanat (MNHW, 4), track entrance, 500 m el., 22°11’S 166°31’E, berlesate, 06-v-2005, lot 12264, Monteith (QMB, 4), 500 m el., 22°10’S 166°31’E, 26-viii-1978, S. & J. Peck (CNC, 1), 400-500 m el., 22°11’S 166°31’E, primary forest, 18–19-x-1998, Löbl (MBC, 1; MHNG, 6); Mt. Mou, summit, 1200 m el., 22°04’S, 166°21’E, rainforest litter, 24-v-1984, Monteith & Cook (QMB, 2), top camp, 1150 m el., 22°04’S, 166°21’E, berlesate, sieved litter, 27-xii-2004, lot 12013, Monteith (QMB, 2). Non-type female specimen: Forêt Cachée, 250 m el., 22°11.5’S 166°47.2’E, sifted litter, 26-x-2008, Wanat (MNHW, 1).

As in the species above, this species epithet elides the type locality, Mt. Mou, with the genitive, adjectival ending -ensis. As Dr. Barry P. Moore had both diagnosed this species from the following M. kanak through the use of male genitalic characters, and had chosen a holotype specimen, he is given senior author status for this species.

This species is restricted to the southern portion of Grande Terre, from Mt. Mou on the west, Mts. Koghis north of Noumea, and with a easternmost record from Forêt Cachée based on a single non-type female specimen (Fig. 25). Collection localities range 250–1200 m elevation. Given that 24 of the 35 specimens are labeled from Berlese samples or sieved litter, and another 7 specimens (1, S. & J. Peck, CNC; 6, Löbl, MHNG) were collected by coleopterists studying the microcoleopteran litter fauna, it can be concluded that this species occupies the ground-level litter layer.

This second of the species triplet also including M. mouensis and M. picdupinsensis can be diagnosed externally by characters listed in the M. mouensis diagnosis. This species and the following M. picdupinsensis are adelphotaxa based on possession of the synapomorphous hitch on the apical surface of the male aedeagal median lobe (Fig. 7, character 112, state 1). This species can be diagnosed from M. picdupinsensis by the hitch configuration being a well-developed apical invagination (Fig. 21A–D, F–K), the level of invagination, curvature and length of the apex varying among populations assigned to this species (Fig. 26). In these instances the apical invagination is much more developed than in the sister species below (Fig. 21L–N). Much like the externally-cryptic species pair M. fleutiauxi and M. jeanneli (Fig. 9D–E), these two species are indistinguishable based on external characters. They are treated as distinct species because just as in the M. fleutiauxi + M. jeanneli pair, female reproductive tract characters also differ between the two taxa. In M. kanak females, the bursa copulatrix is more parallel-sided in ventral view, with the apex narrowed (Fig. 23D–E). Also, the basal gonocoxites bear a narrow, spiculate mediobasal band of fine, setose spicules (Fig. 24D), versus basal gonocoxites with a broader spiculate mediobasal band of spatulate spicules in M. picdupinsensis (Fig. 24E). Standardized body length 3.0–3.8 mm (Fig. 20D–F) for all population samples except that from Col de Yaté, for which the three specimens range 2.9–3.2 mm length (Fig. 20G). Chaetotaxy +/+//+/–//+/2/+/+.

Figure 21. 

Male aedeagal median lobe and parameres, and ring sclerite–mediotergite plus antecostal margin, tergite IX–of Mecyclothorax (Phacothorax) spp.: A–B, M. kanak, right view, dorsal view in situ (Mt. Humboldt, 630 m); C–D, M. kanak, right view, dorsal view in situ (Mt. Humboldt, 1400 m); E, M. kanak, form Q, right view (Mt. Humboldt, 1300 m); F–G, M. kanak, right view, dorsal view in situ (Mt. Dzumac); H–I, M. kanak, right view, dorsal view in situ (Rivière Bleue); J–K, M. kanak, right view, dorsal view in situ (Col de Yaté); L–N, M. picdupinsensis, right views, dorsal view of ring sclerite. See Table 2 for abbreviations.

Figure 22. 

Paired left (above) and right (below) parameres of Mecyclothorax (Phacothorax) spp. (ectal view): A, M. kanak; B, M. picdupinsensis.

Figure 23. 

Female reproductive tract, gonocoxites and associated laterotergites, Mecyclothorax (Phacothorax) spp: A, M. manautei; B, M. paniensis; C, M. mouensis; D, M. kanak (Mt. Dzumac; common oviduct artificially darkened to show configuration); E, M. kanak (Pic du Grand Kaori); F, M. picdupinsensis. See Table 2 for abbreviations.

Figure 24. 

Left female gonocoxa of Mecyclothorax (Phacothorax) spp., ventral view: A, M. manautei; B, M. paniensis; C, M. mouensis; D, M. kanak; E, M. picdupinsensis. See Table 2 for abbreviations.

(n = 24). Head capsule elongate, eyes small, very convex, ocular lobe-genal juncture evenly curved, a very shallow groove indicating limit of ocular lobe; 12–14 ommatidia along horizontal diameter of eye; ocular ratio 1.41–1.54, ocular lobe ratio 0.74–0.81, EyL/EyD = 2.16–2.45; frontal grooves narrowly incised, sinuously convergent to pit at frontoclypeal suture, extended onto clypeus; mandibles moderately elongate, mandibular ratio 1.60; ligula narrowed to a moderately broad, slightly convex anterior margin, the two ligular setae separated by 1–2 setal diameters; paraglossae thin, extended twice as far beyond ligular margin as their basal length to margin, apex visibly spiculate (100×); antennae moderately elongate, antennomere 9 length 2.1× maximal breadth; antennomere 3 glabrous except for apical ring of setae. Pronotum very transverse, distinctly cordate, lateral margins sinuately concave anterad obtuse-rounded hind angles (Fig. 20D–G), MPW/BPW = 2.31–2.64, MPW/PL = 1.27–1.37; front angles slightly protruded, obtuse, APW/BPW = 1.27–1.48; median base unmargined basally, trapezoidally depressed relative to disc, the median longitudinal impression divided basally into two transverse impressions that isolate disc from base, each transverse basal impression terminated laterally in a short linear laterobasal depression; median longitudinal impression finely incised on disc, terminated anteriorly just anterad anterior transverse impression, a narrow fovea at posterior juncture with basal transverse impressions; anterior transverse impression shallow, broad, traceable to front angles; proepisternum separated from prosternum by a shallow groove anteriorly, and deep, distinct groove ventrally; smooth anteapical impression well developed laterally, continuous though shallower ventrally; prosternal process broadly, shallowly depressed between procoxae, the shallow depression extended 1/3 distance toward anterior prothoracic margin. Elytra broadly hemiovoid, humeri well-extended laterally before lateral margins curve posteriorly; basal elytral groove posteriorly curved laterad obtuse humeral angle, with three punctate depressions at the base of sutural and striae 5 and 5; MEW/EL = 0.81–0.93; sutural stria well developed in basal 2/3, striae 2–3 traceable on disc near positions of dorsal elytral setae, all three irregularly depressed with intermittent crenulations or elongate punctures along their length; stria 4 indicated by an intermittent series of shallow longitudinal depressions; striae 1 and 2 shallow and traceable, and stria 8 evident on elytral apex; elytra appressed and conjoined apically, the sutural margin upraised at apex. Pterothoracic mesepisternal anterior furrow with 5 depressions in 1–2 irregular rows; mesosternal-mesepisternal suture complete (as in Fig. 3A); metepisternum foreshortened, lateral length/maximum width = 1.1–1.25; metepisternal-metepimeral suture complete though fine laterally. Abdomen with very elongate, shallowly curved crescent-like depression along suture between first and second ventrite, second ventrite only slightly depressed within crescent; suture between second and third ventrites reduced though traceable laterally; ventrites 3–6 with broad, shallow, linear plaques near lateral margin. Microsculpture of frons reduced, surface glossy, indistinct transverse mesh–sculpticell breadth 2× length–visible over portions of vertex; pronotal disc glossy but with transverse sculpticells visible outside areas of reflection, trapezoidal median base glossy with indistinct transverse mesh anterad laterobasal depression; elytra opalescent, disc covered with very finely separated transverse lines, elytral apex covered with elongate transverse sculpticells and lines.

Male genitalia (n = 25). Antecostal margin of abdominal mediotergite IX angulate, not extended (Fig. 21B, D, G, I); right paramere narrow, extended as a very narrow whiplike extension which flexibly articulates with the base, both ventral and dorsal margins glabrous, with two apical setae (Fig. 22A); left paramere moderately broad basally, evenly narrowed to a whiplike apex, two longer apical setae present; aedeagal median lobe variously robust, broader relative to length in specimens with a shorter aedeagal apex (Fig. 21A, F), and narrower relative to length in males with more gracile median lobes (Fig. 21C, H, J); median lobe apex variously bifurcate–except for the infraspecific variant, form Q discussed below (Fig. 21E)–with an apical aedeagal invagination laterally splitting the tip, that invagination continued laterally on the median lobe toward the ostial opening (Fig. 21A, C, F, H, J); aedeagal apex variously extended and curved, from short and broad, and briefly extended beyond the ostial opening (Fig. 21A, F), to more elongate broadly extended and slightly downturned (Fig. 21H), to more elongate and narrowly extended (Fig. 21C), to very narrowly extended and distinctly curved (Fig. 21J); median lobe internal sac with translucent dorsal plate, most visible in well-sclerotized specimens (Fig. 21A, E, J), and a longitudinal apical field of microspicules (Fig. 21A, J).

One of a series of nine males from Mt. Humboldt, 1300 m el., 6–7-xi-2002, Monteith & Wright, lot 1076 (QMB) exhibits a broad aedeagus with a rounded tip, the ostial opening more asymmetrical apically (Fig. 21E), herein dubbed form Q. The other eight males of this particular collecting series all exhibit aedeagal apices similar to those from Mt. Humboldt, 1400 m (Fig. 21C). There are no external differences discernible among the males of this series, and no other examined male from Mt. Humboldt or anywhere else across the distributional range exhibits the “form Q” aedeagal configuration. Therefore this form is considered an infraspecific variant without nomenclatural status, with its evolutionary basis requiring further study.

The geographic pattern of aedeagal configuration shows that populations in the southern end of the range include males with a longer, narrower, and more curved aedeagal apex (Fig. 26, populations G, H, I). The extreme of this trend is observed in two males from Col de Yaté (Fig. 26, population G). The beetles comprising the Col de Yaté sample also tend to be smaller, though the size range of the three specimens of this population sample overlap the ranges of other populations, precluding diagnosis by size. Given the trend toward longer, narrower aedeagal apices in the south, and the demonstrated variation in aedeagal apices among other population samples (e.g. Fig. 26, population samples C, F), this variation is considered infraspecific.

Figure 25. 

Geographical distributions of Mecyclothorax (Phacothorax) spp. (asterisked locality attributed to M. mouensis based on non-type female specimen).

Female reproductive tract (n = 4). Bursa copulatrix length 1.1–1.4× circumference, its surface thin, translucent, slightly to not wrinkled (Fig. 23D–E); spermathecal duct entering at apex of bursa separate from bursa-common oviduct juncture; rounded helminthoid sclerite on bursal wall between, and separate from both, bursal-common oviduct juncture and spermatheca; spermatheca of only slightly greater circumference than spermathecal duct, reservoir about 1/2 length of spermathecal duct, spermathecal gland duct entering at base of spermathecal reservoir (Fig. 23E); ligular apophysis present on common oviduct; basal gonocoxite 1 with apical fringe of two to unilaterally three setae laterally, a very small setae may be present immediately mesad, and several smaller setae occur along apex of medial margin (Fig. 24D); medial margin bearing a dense field of spiculate microtrichia basally, this field about 3–4 microtrichia broad and appearing like the hooklike surface of a Velcro® closure; gonocoxite 2 moderately broad basally, basal width 1/2 medial length; two gracile lateral ensiform setae of moderate length present.

Types – Holotype male (MNHN): NEW CALEDONIA / Mt Dzumac / 28 May 1987 / R.Raven // Q.M. Berlesate No. 800 / 22°03’S. 166°28’E. / Rainforest 900m / Litter // QUEENSLAND / MUSEUM LOAN / DATE: Nov. 2003 / No. LEN-1686 (green label) // HOLOTYPE / Mecyclothorax / kanak / B.P. Moore & J.K. / Liebherr 2017 (black-bordered red label).

Paratypes (181 specimens; CUIC, EMEC, MBC, MHNG, MNHW, NHMW, PMGC, QMB): see Suppl. material 2.

This species is named to honor the Kanak people of New Caledonia. As the species epithet kanak is not derived from Latin, it is to be treated as indeclinable (I.C.Z.N. 1999, Article 31.2.3). Dr. B. P. Moore diagnosed this species from the preceding sibling species M. mouensis, and as such it is appropriate that he receive senior authorship for the species.

This species is densely and abundantly distributed across the southern reaches of Grande Terre, with records from Mt. Humboldt south to Forêt Nord (Fig. 26). Collecting localities range from 70 m elevation along the Tontouta River, to 1500 m on the slopes of Mt. Humboldt. Professor Alexander von Humboldt (Wulf 2015) would no doubt be very interested to learn that this species occurs from 580–1500 m elevation on his namesake mountain, inhabiting lowland rain forest, montane rain forest, and high-altitude maquis (Mueller-Dombois and Fosberg 1998), where this species was collected from sifted litter under Callitris neocaledonica Dümmer (1, Wanat, MNHW). Of the 177 specimens examined, 133 were labeled as collected in sieved litter or by Berlese extraction. A further 34 specimens (Löbl, MHNG) can also be assigned as the products of these methods. This leaves the remaining 6% of specimens to be divided between such collecting methods as headlamp search at night, “at light”, flight intercept trap, and no data. Thus this species can be characterized as a fastidious denizen of the ground-level litter layer.

Figure 26. 

Recorded geographical distribution of M. kanak (including population samples A–I for which representative male aedeagi are figured): numbers of males sampled for each locality indicated in lower left of boxes. Sampled population localities include: A, Mt. Humboldt, 1300–1400 m; B, Mt. Humboldt, 600 m; C, Mt. Dzumac; D, Rivière Bleue, 800 m; E, Rivière Bleue, 400 m; F, Mts. Koghis; G, Col de Yaté; H, Pic du Grand Kaori; I, Forêt Nord.

This final member of the species triplet also including M. mouensis and M. kanak can be diagnosed from the former by characters listed in the M. kanak species diagnosis. As stated above, this species cannot be diagnosed from M. kanak based on external characters. The basis for species recognition lies both in the form of the male aedeagal median lobe apex–i.e., broadly rounded with a minute hitch present (Fig. 21L)–and female gonocoxae with a broad mediobasal patch covered with quadrate cuticular scales (Fig. 24E). Also, based on specimens at hand, the female bursa copulatrix is shorter and broader in this species, and the helminthoid sclerite is more narrowly extended as a laminar structure that is heavily melanized (Fig. 23F). Standardized body length 3.03.4 mm. Chaetotaxy +/+//+/–//+/2/+/+.

(n = 5). The description of M. kanak can serve to describe this species, with substitution of the following ranges of ratios of the measured specimens: ocular ratio 1.44–1.52; ocular lobe ratio 0.71–0.80; EyL/EyD = 2.08–2.38; MPW/BPW = 2.30–2.44; MPW/PL = 1.33–1.38; APW/BPW = 1.32–1.36; MEW/EL = 0.85–0.89.

Male genitalia (n = 2). Antecostal margin of abdominal mediotergite IX angulate, not extended (Fig. 21M); right paramere narrow, evenly narrowed from narrow base to whiplike apex, with one seta near midlength on ventral margin complementing two long apical setae (Fig. 22B); left paramere narrow basally, evenly narrowed to whiplike apex, two longer apical setae present; aedeagal median lobe robust, broad dorsoventrally, evenly curved dorsally and ventrally to a broadly downturned apex which bears a variously developed apical invagination, present as a small tubercle or change of angle of the apical margin (Fig. 21L); aedeagal median lobe internal sac with sclerotized region in position of dorsal plate, internal sac folded longitudinally toward apex (Fig. 21L, N).

Female reproductive tract (n = 1). Bursa copulatrix length subequal to circumference, its surface thin, translucent (Fig. 23F); spermathecal duct entering at apex of bursa separate from bursa-common oviduct juncture; rounded laminar helminthoid sclerite extended from bursal wall between, and separate from both, bursal-common oviduct juncture and spermatheca; spermatheca of only slightly greater circumference than spermathecal duct, reservoir about 1/2 length of spermathecal duct, spermathecal gland duct entering at base of spermathecal reservoir (Fig. 23F); ligular apophysis present on common oviduct; basal gonocoxite 1 with apical fringe of two setae laterally, a very small setae may be present immediately mesad, and several smaller setae occur near apex of medial margin (Fig. 24E); medial margin bearing a dense field of microtrichia basally, this field about 8 microtrichia maximal breadth, with the macrotrichia appearing like flattened scales; gonocoxite 2 moderately narrow basally, basal width 0.4× medial length; two gracile lateral ensiform setae of moderate length present, the apical seta broader.

Types – Holotype male (MNHN): NEW CALEDONIA 11787 / 22°15’Sx166°49’E, 280m / Pic du Pin, site 1,rainfor. / 26Nov2004, berlesate / G.Monteith,P.Grimbacher // QUEENSLAND / MUSEUM LOAN / DATE: July 2005 / No. LE 05.24 // New Caledonia Mecyclothorax revision / measured specimen 1 // HOLOTYPE / Mecyclothorax / picdupinsensis / J.K.Liebherr 2017 (black-bordered red label) /

Paratypes (11 specimens). NEW CALEDONIA: Pic du Pin[code PA 48], 22°15’S 166°49’E, 28-vi-1970, Franz (NHMW, 3), base, 280 m el., 22°14.9’S 166°49.7’E, sifted rainforest, litter, 26-xii-2006, Wanat & Dobosz (MNHW, 1), 22°15’S 166°49’E, sifted litter, 22-x-2008, Wanat (MNHW, 1), site 1, rainforest, 280 m el., 22°15’S 166°49’E, berlesate, 26-xi-2004, lot 11787, Monteith & Grimbacher (QMB, 5), 21-xii-2004, lot 12045, Monteith (QMB, 1).

This species name represents the genitive adjectival form of the type locality, Pic du Pin; picdupinsensis. This final species name includes reference to the New Caledonian Pine, Araucaria columnaris J. R. Forster and W. J. Hooker, and partially recapitulates the final species named in Liebherr (2016); Cyphocoleus iledespinsensis Liebherr.

This species is restricted to the vicinity of Pic du Pin, southern Grande Terre (Fig. 25), with all collecting localities recorded at 280 m elevation. Nine of the 12 specimens were collected from sieved litter, whereas three specimens (NHMW) are associated with the collecting note: “Total stehendes Stammen von Aruacaria biramulata (Herbert Franz field notebook: Jäch, pers. comm.)”: Thus this species may climb the lower reaches and boles of larger trees in addition to occupying the ground-level litter layer.