Tropopterus giraudyi Solier by subsequent designation (Enderlein 1909).

Tropopterus may be placed in the Moriomorphini based on: presence of a seta in the mandibular scrobe; frontal grooves present mesad eyes and traversing the frons anteromedially to the frontoclypeal suture; clypeus narrower than distance between antennal insertions; penultimate maxillary palpomeres glabrous, not setose over the entire surface; apical palpomeres fusiform and as long and broad as penultimate palpomere; head with two pairs of supraorbital setae; procoxal cavities closed posteriorly; mesocoxal cavities conjunct; prothoracic leg bearing an antennal cleaner with a distal zone of short, separated setae, and a basal arc of confluent setae that performs the cleaning function (Grade C of Hlavac 1971). The first eight characters will place Tropopterus within Psydrini in the system of Roig-Juñent and Domínguez (2001). The last antennal cleaner character differentiates the Psydrini from Moriomorphini (Baehr 1998; Liebherr 2020), as Psydrini exhibit a shorter, less well-developed antennal cleaner (Grade B of Hlavac 1971) versus that observed in Moriomorphini. The morphological results conform to phylogenetic hypotheses based on molecular sequence data (Maddison et al. 1999, 2019).

Within Moriomorphini Tropopterus may be diagnosed by the inversion of the male aedeagus, a character observed in several other Moriomorphini: Mecyclothorax storeyi Moore (1963) of Queensland; and polymorphically within Western Australian populations of Mecyclothorax punctipennis (MacLeay) (Liebherr and Will 2015). Nowhere else in Moriomorphini does this character define a monophyletic grouping of species. Other characters supporting monophyly of Tropopterus include deep, pitlike paramedial depressions of the mentum, also observed in Meonis spp. of Australia (Moore 1963; Liebherr 2020). The metathoracic scutellum projects little onto the disc of the elytra, whereas it is more narrowly triangular and elongate in the sister group Pharetis (Liebherr 2020). The elytral basal groove (when present) meets the lateral marginal depression at a distinct angle, whereas this juncture is more rounded in Pharetis thayerae. Both Pharetis and Tropopterus are characterized by a tooth along the dorsal margin of the humerus. Though the elytral striae vary in configuration among Tropopterus spp., their reduction is derived, and the presence of only the first, or sutural stria in a fully developed condition on the elytral apex is a synapomorphy. All species of Tropopterus are characterized by vestigial flight wings, and the metepisternum is correspondingly foreshortened. That sclerite’s dimensions range from length 1.2× breadth to length and breadth subequal; length measured along lateral margin and maximal breadth measured perpendicular to that line. Relative to Pharetis, the fourth metatarsomere is more emarginate, with the outer, lateral lobe longer than the inner, mesal lobe. Finally, the setal configuration across the dorsal body is diagnostic, though not synapomorphic, with: presence of both anterior and posterior supraorbital setae; presence of both lateral and basal pronotal setae; presence of the parascutellar setae; absence of any dorsal elytral setae; and presence of both subapical and apical setae near the elytral apex. Consistent with most other moriomorphines there are seven (rarely eight) anterior lateral elytral setae bordering the eighth stria, and six posterior setae: though the posterior two setae of the anterior series, or the anterior two setae of the posterior series may be isolated from their respective series’ partners in T. robustus, sp. nov. Also, males, where known for the various species, have two setae each side of the apical abdominal ventrite, representing a potential synapomorphy for the genus relative to its Australian adelphotaxon, Pharetis thayerae Liebherr (2020). The male aedeagal median lobe is robust, i.e. broad dorsoventrally, with the internal sac flagellar apparatus also large (e.g. Fig. 4A). The aedeagal median lobe of males, for all species so far examined, bears dense longitudinal pleating across the sclerotized surface surrounding the ostium (Fig. 4A, C), with this pleating allowing broad extension of the aedeagal surface during eversion of the internal sac. Females also have two setae each side along the apical margin of ventrite 6 accompanied by four median setae of length subequal to the more lateral setae, these variously arranged in an apically broad trapezoid or in a straight line. The female reproductive tract is characterized by absence of a helminthoid sclerite; a sclerotized projection at the junction of the bursa copulatrix wall, common oviduct, and spermathecal duct (Liebherr and Will 1998). The derived loss of the helminthoid sclerite, observed across many other moriomorphine taxa, is shared with Raphetis Moore of southeastern Australia (Liebherr 2020).

Although Tropopterus Solier (1849) was used by major authorities throughout the 19^th century (see synonymy above), Gemminger and Harold’s (1868) unjustified emendation Tropidopterus was adopted by Enderlein (1909), Moore (1963), and subsequently followed by Baehr (1998). The original spelling of Tropopterus has also been used more recently (Straneo 1954; Roig-Juñent and Domínguez 2001; Maddison and Ober 2011; Larochelle and Larivière 2013). Though both variants have been used, the original spelling predominates and so the unjustified emendation Tropidopterus cannot be considered “in prevailing usage” (ICZN 1999, Article 33.2.3.1). Thus Tropidopterus must be rejected in favor of the original spelling.

In addition to the three Tropopterus spp. described by Solier (1849), Germain (1911) listed “T. plicicollis” ms. name, as an undescribed species held in the Museo Nacional de Historia Natural, Santiago, Chile, assigning it his “N.^os del Catálogo primitivo” entry 500. This combination was never validly described (Lorenz 2005). However a specimen labelled as per Germain’s protocol (“459 / Catapilcanus / P. G. (ined.)”) was described as Merizodus catipileanus by Jeannel (1962). That name is synonymized below with T. montagnei Solier. Germain’s (1911) list also includes undescribed specimens labelled with his catalog numbers 458 and 460, bracketing the number assigned to “Catapilcanus.” Germain assigned those numbers to his manuscript names Trechus ebeninus and Trechus araucanus, with Jeannel subsequently describing those specimens as Trechisibus araucanus (Jeannel 1962: 562) and Trechisibus ebeninus (Jeannel 1962: 577). Thus, some of the undescribed Germain (1911) material was used by Jeannel as the basis for new species he described in 1962, but there is no evidence that any specimens assigned to “T. plicicollis”, catalog entry 500, were part of Jeannel’s working material, nor was Germain’s name validated in any subsequent publication. Thus Germain’s (1911) “Tropopterus plicicollis (P. G. ined.)” has no nomenclatural standing.

Straneo (1954) described Tropopterus peruvianus from two specimens (Sivia, Peru, 13-v-1936, 520 m el.) collected during the Südperu-Expedition of the Naturhistorisches Museum, Hamburg. Although Straneo’s description was published in 1954, the material had been originally described in 1942, with the specimens returned to the Hamburg museum and subsequently destroyed in the Allied firebombing of 1943. That the types of this species were lost in the destruction of the museum was documented by Weidner (1976; Dr. M. Husemann pers. comm.). Straneo (1954) recorded the female type used as the basis for the description as being of 8 mm body length. His diagnosis for T. peruvianus, translated from the Italian, follows:

“It differs from T. giraud[y]i Sol. by the basally non-sinuate pronotum; it also has distinctly obtuse pronotal basal angles; the 1^st stria is strongly impressed from approximately 1/6 of the elytra length, immediately commencing as a distinct impression and not with isolated punctures; the eighth stria is about as long as the 1^st; the third interstria has a small puncture present the apical half; the two basal antennal articles extend beyond the pronotal base, etc. From T. duponcheli[i] Sol. it differs by the first and second striae stria reaching the elytral base, and because the lateral pronotal [margin] is very gradually enlarged from the anterior setal pore towards the base.”

This diagnosis does not fit any of the species treated below. Indeed the presence of a puncture in the third interval does not fit the diagnosis of Tropopterus, suggesting phylogenetic placement outside the presently treated taxa. Thus T. peruvianus Straneo is to be treated as an available nomen dubium with its identity to be stabilized through new collection and designation of a neotype.

(n = 3). These somber-colored, small-bodied beetles – standardized body length 5.7–6.2 mm – can be recognized by the isodiametric elytral microsculpture that gives the surface a granulate appearance. The legs are dark, with the femora and tibial apices as dark as the piceous head, pronotum, and elytra. The pronotum is moderately transverse (MPW/PL = 1.21–1.27) with the pronotal hind angle obtuse, the lateral margin straight anterad the hind angle. The elytral striae 1–4 are obsolete, only traceable on the disc and without punctation. Only the first, sutural stria is ± traceable on the elytral apex. The eyes are small (ocular ratio = 1.32–1.36) with about 18 ommatidia crossed along a horizontal diameter of the eye. The vertex is glossy, contrasted with the transverse mesh microsculpture of the pronotum, and the granulate isodiametric microsculpture of the elytra. Ventrally the prosternum is broadly flattened to moderately depressed medially from the prosternal process anterad to 2/3 of the prosternal length, and the mesepisternum is smooth, with 2–3 irregular punctures dorsoventrally arranged on its concave surface.

Female reproductive tract (n = 1). Bursa copulatrix columnar, length twice breadth, compressed under microslide cover slip (Fig. 7A), bursal walls relatively thick, translucent; spermatheca globose (separated in single dissection); basal gonocoxite 1 with apical fringe of two setae (Fig. 8A); apical gonocoxite 2 broadly triangular, base extended laterally, with two moderate lateral ensiform setae and one dorsal ensiform seta; apical sensory fossa with two nematiform setae.

Figure 7. 

Female reproductive tract and gonocoxae of abdominal segment IX, ventral view. A. T. montagnei; Petorca Prov., Q. Tigre Zapallar, Catapilco (MNHN). Spermatheca disassociated from bursal assemblage. B. T. giraudyi; Llanquihue Prov., P. N. Vicente Pérez Rosales (FMNH). C. T. robustus; Malleco Prov., M. N. Contulmo (FMNH). D. T. canaliculus; Malleco Prov., P. N. Nahuelbuta (FMNH). E. T. duponchelii; Arauco Prov., Caramavida (MCZ). F. T. minimucro; Valdivia Prov., P. N. Oncol (EMEC). For abbreviations used to label structures see Table 1. Vertical scale bars: 0.5 mm.

Figure 8. 

Left gonocoxa (except where noted), ventral view, for Tropopterus spp. Specimen information is parallel to that in Figure 7A–F. For abbreviations used to label structures see Table 1. A. T. montagnei. B. T. giraudyi. C. T. robustus. D. T. canaliculus. E. T. duponchelii. F. T. minimucro (right gonocoxa).

T. montagnei lectotype female (MNHN) hereby designated: S. Iago (handwritten on blue label) // MUSEUM PARIS / CHILI / Cl. Gay 1845 (grey label) // 9 45 (round blue label) // TYPE (red label) // Tropopterus / montagnei / Sol. Sn. Iago (handwritten white label) // Tropopterus / Measured / Specimen #1 / det. J.K. Liebherr 2019 // LECTOTYPE / Tropopterus / montagnei / Solier / des. Liebherr 2019 (black-margined red label). PARALECTOTYPE female (MNHN): MUSEUM PARIS / CHILI / Cl. Gay 1845 (grey label) // 9 45 (round blue label) // Tropopterus / Measured / Specimen #2 / det. J.K. Liebherr 2019 // PARALECTOTYPE (as above).

Merizodus catapileanus holotype female (MNHN): Catapilco // 459 // Chili / Aconcagua / Catapilco // Catapilcanus / P. G. (ined.) / 459 // Merizodus // catapileanus / m. (hand written cursive) // Tropidopterus / catapileanus / det. P. M. Johns // 163 // Tropopterus / Measured / Specimen #3 / det. J.K. Liebherr 2019 // HOLOTYPE / Merizodus / catapileanus / Jeannel 1962 (black-margined red label) // Tropopterus / montagnei / Solier / det. J.K. Liebherr 2019. Because Jeannel (1962) stated this species name was based on “une femelle,” he designated a holotype by monotypy. This female was card-mounted with the abdomen missing. As Jeannel routinely mounted dissected genitalia on separate pins (see the Tropopterus giraudyi paralectotype) it appears this species was dissected with the abdomen plus genitalia mounted separately, the latter subsequently disassociated. The data on the specimen agree with those provided in Jeannel’s (1962: 606) description. Also, Jeannel’s textual description fits the specimen with regard to size, wing configuration, general habitus, and absence of dorsal elytral setae. However, the illustration accompanying the text deviates significantly from the specimen by showing the penultimate palpomere as setose, and the elytra with eight lateral elytral setae (arranged as 4 + 4). In fact the penultimate palpomere is glabrous, and the lateral elytral setae are arranged as 6 + 1 + 6; i.e. a single seta separated from the anterior and posterior series of six setae each. Admittedly, there was excessive mucilage filling the elytral marginal depression, and so the setae were apparently missed. The consequence of these mistakes was Jeannel’s placement of this species in a genus of the Zolini.

Date locality information for all specimens. Chile: Petorca Prov. (labelled “Aconcagua”), Catapilco, 32°34.10'S, 71°16.52'W, Germain (MNHN, 1); Q. Tigre Zapallar (= Catapilco), 13-vii-1966, Pena (MNHN, 1). Santiago Prov., Santiago (lectotype and paralectotype), 33°26.75'S, 70°40.12'W, Solier (MNHN, 2).

No habitat data are associated with the types of either names representing this species. This species is restricted to the Santiagan entomofaunal region (Fig. 9A; O’Brien 1971).

Figure 9. 

A–I. Geographic distributions of Tropopterus spp. A. T. montagnei. B. T. giraudyi. C. T. peckorum. D. T. robustus. E. T. canaliculus. F. T. duponchelii. G. T. trisinuatus. H. T. minimucro. I. T. fieldianus. J. Geographical distributions of Tropopterus spp., labeled as per figures above, hierarchically arranged by phylogenetic relationships of the taxon cladogram, Fig. 10.

(n = 5). This large-bodied species (standardized body length 7.2–8.3 mm) is easily diagnosed by the smooth elytra with the sutural stria completely effaced to irregularly punctate basally (Fig. 1B), the punctures, when present, broad, very shallow, and irregularly distributed. Conversely, the sutural stria is distinctly punctate behind the elytral midlength, transforming to a very narrow canaliculate depression near the elytral apex. The eyes are moderately convex (ocular ratio = 1.41–1.47) with about 23 ommatidia crossed by a horizontal diameter of the eye. The pronotal hind angles are right to obtuse, sharp, with the lateral margins subparallel anterad the angles. The pronotal apical margin is finely, continuously margined medially, and the pronotum is relatively narrow (MPW/PL = 1.21–1.25) compared to the similar-appearing T. duponchelii (MPW/PL = 1.25–1.32; Fig. 1F) and T. minimucro (MPW/PL = 1.27–1.37; Fig. 2B). Ventrally the prosternum is deeply depressed medially, the broad depression extended from the prosternal process more than halfway toward the front margin, and the mesepisternum is broadly punctate, with 8–9 punctures in 2–3 dorsoventral rows. The glossy vertex contrasts with the pronotum that bears a dense, shallow transverse mesh, and the iridescent elytra covered with dense transverse lines.

Male genitalia (n = 13). Aedeagal median lobe robust, broad dorsoventrally from base to apex, the broadly rounded apex bearing a well-developed mucro on its ventrobasal aspect (Fig. 3A); internal sac lightly sclerotized (sac not everted), with a sinuous spicular sclerite that would be positioned on the sac apex when everted. Antecostal apodeme of laterotergite IX (Deuve 1993) broadly angulate distally, the apex of the apodeme not extended much beyond lateral arms of the apodeme (Fig. 3B). Right paramere of median lobe elongate, slightly broader medially, with one or two long setae apically, six to eight setae along ventral margin, and several more smaller setae apically (Figs 6A, B); left paramere broad basally, variously narrowed apically into a parallel-sided extension (Fig. 6A), or an evenly narrowed apex (Fig. 6B), the apex of the paramere bearing two or three longer setae plus several shorter subapical setae.

Female reproductive tract (n = 2). Bursa copulatrix columnar, length 2.5× breadth, compressed under microslide cover slip (Fig. 7B), bursal walls relatively thick, translucent; spermatheca ovoid; spermathecal gland elongate, broadest distally; spermathecal gland duct entering spermathecal duct basad spermathecal reservoir; basal gonocoxite 1 with two apical fringe setae (Fig. 8B); apical gonocoxite 2 narrowly triangular, base little extended laterally, with one or two (Fig. 8B) lateral ensiform setae, one dorsal ensiform seta, and two apical nematiform setae.

Lectotype female (MNHN) hereby designated (card mounted): S. Iago (handwritten on blue label) // MUSEUM PARIS / CHILI / Cl. Gay 1845 (grey label) // TYPE (red label) // Tropopterus / Giraudyi / Sol. Sn. Iago (handwritten white label) // 9 / 45 (pale blue circle) // LECTOTYPE / Tropopterus / giraudyi / Solier / des. Liebherr 2019 (black-margined red label). Paralectotype male (MNHN) (card mounted, genitalia dissected and removed): MUSEUM PARIS / CHILI / Cl. Gay 1845 (grey label) // 9 / 45 (pale blue circle) // Tropidopterus / giraudi Sol. // PARALECTOTYPE (as above). Male genitalia (card mounted): Tropidopt. / Giraudi / Chili / ’71 // PARALECTOTYPE (as above).

Date locality information for all specimens. Argentina: Neuquén Prov., Pucará to Lago Venados road, Lago Lacar, 40°10.50'S, 71°21.50'W, 24–25-i-1972, Herman (NMNH, 1). Chile: Cautín Prov., Bellavista, Lago Villarrica, 39°12.55'S, 72°08.14'W, 250 m el., 8-i-2006, Will (EMEC, 1); Villarrica, 30 km NE, 39°09.23'S, 71°51.82'W, 1–30-i-1965 (MCZ, 1). Chiloé Prov., Chepu (det. Straneo, see Straneo [1969]), 42°02.03'S, 73°58.31'W, 9-x-1958, Kuschel (MNHN, 1); P. N. Chiloé, under logs/rocks, 42°36.84'S, 74°06.25'W, 20-i-2002, Will & Lew (EMEC, 1), Rio Cipresal, above, lot DRM 06.085, 42°34.70'S, 74°04.98'W, 195 m el., 20–21-i-2006, Maddison & Will (OSAC etoh, 2), Quemchi, 11 km w of, 11 km E Hwy. 5, Valdivian rainforest remnant w/ thick bamboo understory, beating vegetation, 42°10.40'S, 73°35.73'W, 140 m el., 10-xii-2002, Clarke (FMNH, 3). Llanquihue Prov., P. N. Vicente Pérez Rosales, Ensenada, 9.2 km NE, on road to Petrohué, Valdivian rainforest w/ Nothofagus spp., lot 987, pyr.-fogging old logs, 41°10.20'S, 72°27.10'W, 125 m el., 2-i-1997, Newton & Thayer (FMNH etoh, 1), 28-i-1997, Newton & Thayer (FMNH etoh, 1), 4–28-i-1997, Newton & Thayer (DRM DNA voucher DNA0532, FMNH on loan to OSAC, 1), Volcán Osorno, SW slope, c. km 11 to La Burbuja, low Nothofagus dombeyi w/bamboo & shrub understory, lot 1065, pyr.-fogging old mossy logs, 41°07.9'S, 72°32'W, 1090 m el., 15-xii-2002, Newton & Thayer (FMNH, 3). Malleco Prov.: P. N. Nahuelbuta, Los Portones entrance, 2.3 km W, Nothofagus dombeyi + ? antarctica, mostly open understory, lot 1057, pyr. fogging old Nothofagus logs, 37°49.41'S, 72°58.95'W, 1150 m el., 25-xii-2002, Newton, Thayer & Chani (FMNH, 1). Osorno Prov., P. N. Puyehue, Aguas Calientes, forest litter on trail, lot P#85-43, sifting 40°43.66'S, 72°18.11'W 500 m el. 20-xii-1984, S. & J. Peck (FMNH, 1), Anticura, 4 km E, 40°39.73'S, 72°08.1'W, 460 m el., 31-xii-1996, Newton & Thayer (DRM 97-021, DNA voucher DNA0459, FMNH on loan to OSAC, 1), rainforest w/ large Saxegothaea, lot 985-2, pyr.-fogging old logs, 40°39.73'S, 72°08.10'W, 460 m el., 30-i-1997, Newton & Thayer (FMNH etoh, 1), Puyehue, 10 km E, 40°37.00'S, 72°30.68'W, 24-i-1951, Ross & Michelbacher (CAS, 2), 20 km E, 40°36.66'S, 72°24.83'W, 26-i-1951, Ross & Michelbacher (CAS, 1). San Antonio Prov., Santo Domingo, 33°35.50'S, 71°36.33'W, 1-xi-1972 (MNHN, 1). Santiago Prov., Santiago (lectotype, paralectotype), 33°26.75'S, 70°40.12'W, Solier (MNHN, 2). Valdivia Prov., Chaihuin, Res. Costera Valdiviana, lot CH2006.13.H.i.2, 40°03.71'S, 73°35.32'W, 443 m el., 14-i-2006, Will (EMEC etoh, 1), lot CH2006.16.i.2, 40°01.67'S, 73°31.85'W, 511 m el., 16-i-2006, Will (EMEC etoh, 1), headlamp search, 39°58.32'S, 73°39.23'W, 77 m el., 10-xi-2008, Will (EMEC, 1), Corral, 39°53.25'S, 73°25.69'W, xii-1905, Thaxter (MCZ, 3), i-1906, Thaxter (MCZ, 1). Valdivia Prov., P. N. Oncol, Mirador Pilocura, Sendero, 39°41.65'S, 73°18.86'W, 715 m el., 12-i-2006, Will (EMEC, 2), road to P. N. Oncol, 39°41.98'S, 73°20.65'W, 513 m el., 9-xi-2008, Will (EMEC, 1), Cerro Oncol trail, 39°41.89'S, 73°18.07'W, 500 m el., 11-i-2006, Maddison & Seago (OSAC, 2), Puerto Fui, 12 km SSE, Lago Pirehueico, Site F, Coigue-Lenga Forest, N. dombeyi, N. alpina, N. pumilio, under Nothofagus bark 39°58'S, 71°50'W, 1030 m el., 10-i-1988, Ashworth, Figiseth & Maliscke (NDSU, 1), Valdivia Res., Punta Curiñanco, CH2006.13.i.2, 39°41.25'S, 73°21.50'W, 150 m el., 13-i-2006, Will (EMEC etoh, 1). No other data except “x-70” (MNHN, 1); “1611”, Chaudoir colln. (MNHN, 1); “Chili // Tropopterus nitidus [sic]”, Bates colln. (MNHN, 1).

This is the most widely distributed species of Tropopterus. with localities ranging in latitude from 33°27'S–42°37'S (Fig. 9B). Known localities thus occur within the Santiagan, Northern Valdivian, and the northern portion of the Southern Valdivian entomofaunal provinces (O’Brien 1971). Specimens have been collected by sifting in Valdivian rainforest with Nothofagus, by pyrethrin fogging of old Nothofagus logs, under logs and rocks, and by beating vegetation. Tropopterus giraudyi has been contemporaneously collected in localities shared with: Metacorneolabium exuberatum Thayer (1985; Argentina: Neuquén Prov., Pucara, 24–25-i-1972, Herman, NMNH); Glypholoma chepuense Thayer (1997; Chile: Chiloé Prov., Chepu, MNHN); Andotypus ashworthi Spangler (Fikáček et al. 2014; Chile: Llanquihue, P. N. Vicente Pérez Rosales, 9.2 km NE Ensenada on road to Petrohué, FMNH); Anaballetus chilensis (Newton et al. 2017; Chile: Cautín Prov., Bellavista, N. shore Lago Villarrica, FMNH; Chile: Malleco Prov., P. N. Nahuelbuta, 2.3 km W Los Portones entrance, FMNH; and Chile: Osorno Prov., P. N. Puyehue, 4.1 km E Anticura, FMNH). The Neuquén Province, Argentina record from Lee Herman, above, represents the only Argentine record for both Tropopterus and Metacorneolabium Steel (Thayer 1985).

(n = 3). Beetles of this species are distinguished by their small size (standardized body length 5.5–6.0 mm) and narrow bodies. The latter is evidenced by: very flat eyes, ocular ratio = 1.30–1.33; a narrow, quadrate pronotum, MPW/PL = 1.21–1.31; and narrow, relatively flat elytra, MEW/EL = 0.66–0.68. The pronotal median base is longitudinally wrinkled near the narrow basal marginal bead, whereas the anterior margin is smooth medially, with an anterior marginal bead present only in the lateral half of each side. The sutural stria is evident as a series of minute, isolated punctures on the elytral disc, whereas it is effaced on the elytral apex. The elytral basal groove is present, continuous from laterad the parascutellar seta to the obtuse angle where it joins the lateral marginal depression. Ventrally the prosternum is broadly flattened to slightly depressed medially anterad the prosternal process, and the mesepisternum bears 7 or 8 linearly arranged punctures in the dorsoventral depression. The vertex is glossy, the pronotum glossy with indistinct transverse lines, and the elytral disc is covered with an elongate transverse mesh, the sculpticells 2–4× as broad as long.

Head capsule narrow; eyes flat, ocular lobe little-protruded, compound eye covering 0.82–0.83 length of ocular lobe, 18–20 ommatidia across horizontal diameter of eye; antennomeres broadened apically, moderately elongate, antennomere 9 length 1.83× greatest diameter; mandibles elongate, distance from anterior condyle to apex of left mandible 1.91× distance from condyle to lateroapical margin of labrum; mentum basal breadth 2.86× length from lateral apex to base, paramedial pits deep; ligular apex truncate, broad, two setae separated by three setal diameters; paraglossae extended as far beyond ligular margin as distance from paraglossal base to ligular margin. Pronotum relatively narrow, lateral margins straight to slightly sinuate before right to slightly acute hind angles; anterior transverse impression broad and shallow across width; front angles only slightly protruded; lateral marginal depression narrowest at midlength, slightly broader at front angle, broadened progressively toward hind angle; lateral seta separated from lateral marginal depression by one diameter of articulatory socket; laterobasal depression quadrate, oblique with deep inner groove and upraised tubercle in middle of depression. Elytra smooth, striae 2–4 traceable on disc as longitudinal series of minute lenticular punctures, striae 5–7 obsolete; stria 8 present anteriorly near posterior portion of anterior lateral setal series, very shallow at midlength, and deep, continuous inside posterior setal series; lateral marginal depression broad, lined with transverse sculpticells; subapical sinuation broad, shallow, elytral plica evident in lateral view. Metepisternum equitrapezoidal, the maximal width and lateral length subequal; metasternal process rounded apically, apex broadly and the side narrowly upraised in a lateral bead. Abdominal ventrites 3–6 broadly depressed laterally, suture between ventrites 1 and 2 nearly straight, surface of ventrite 2 depressed within slight sinuation; anterior margins of ventrites 4–6 depressed, intersegmental membranes punctate; female apical abdominal ventrite with two setae each side, four shorter medial setae arranged in an apically broader trapezoid. Body coloration pale (specimens appear teneral), concolorous rufobrunneous, legs not paler; ventral surface concolorous, with elytral epipleura, metepisternum, and apical half of ventrite 6 paler, rufoflavous.

Male genitalia (n = 1). Aedeagal median lobe broadest dorsoventrally at base, narrowed slightly to a narrowly rounded apex (Fig. 3C); internal sac with a sclerotized flagellar complex (teneral specimen), with a putative, short flagellum visible. Antecostal apodeme of abdominal IX narrowly rounded, the apex not extended beyond lateral arms (Fig. 3D, although teneral specimen may not have sclerotized fully to attain mature configuration; e.g. Song 2004). Right paramere elongate, slightly broader at midlength with broadly rounded apex, two longer apical setae complemented by eight setae along ventral margin and several very small setae on the dorsoapical surface (Fig. 6C); left paramere broad basally, with short narrow apical extension that bears two longer apical setae plus several very small subapical setae.

Holotype male (FMNH): CHILE: Quillota Prov. / Olmue, La Campana / N.P., 2.XII.1984 // FMHD#85-889, / hygrophilous forest / leaf litter, S.&J. / Peck, P#85-4, Berlese / FIELD MUSEUM NAT. HIST. // Tropopterus / Measured / Specimen #2 / det. J.K. Liebherr 2019 // HOLOTYPE / Tropopterus / peckorum/ J.K. Liebherr 2019 (black-margined red label).

Paratypes: Chile: Quillota Prov., P. N. La Campana (Sector Granizo), Cajón La Opositora, 685 m el., 32°58.80'S, 71°06.93'W, 29.xi–29.xii.2002, sclerophyll forest, ?w/Nothofagus obliqua, FMHD#2002-019, flight intercept trap, Thayer, Newton, Solodovnikov, 1045, FIELD MUSEUM NAT. HIST. (FMNH, 2)

This species is named to honor Stewart Peck and Jarmila Kukalova-Peck for their immense contributions to systematic entomology, and their numerous discoveries of Austral biodiversity.

This species is known from localities in the Santiagan entomofaunal province (O’Brien 1971) at latitudes near 33°S (Fig. 9C). Both collecting events are associated with ground-level microhabitats, either in forest litter via Berlese sifting, or in an octopus-baited carrion trap in sclerophyll forest with Nothofagus obliqua (Brisseau de Mirbel).

(n = 5). The combination of small, very broad body, and punctate discal elytral striae 1 and 2 (Fig. 1D) diagnoses this species: standardized body length 5.2–6.0 mm; pronotal MPW/PL = 1.36–1.41; and elytral MEW/EL = 0.74–0.81. The pronotal hind angle is right to acute, the apex of the angle denticulate, and the lateral margins convergent just before the angles. The pronotum anterior margin is beaded only along the lateral 1/3 to 1/4 each side. The parascutellar striole is absent, and instead the sutural stria continues to the well-developed basal groove laterad the scutellum. These small beetles have the most well-developed elytral striae in the genus, striae 3–7 traceable on the disc, and the sutural stria is narrowly and smoothly grooved apically. Ventrally the prosternum is deeply depressed medially from the prosternal process 2/3 of the way to the anterior prothoracic margin. The mesepisternum is mostly smooth, with only 2 or 3 punctures in a furrow at the deepest part of the sclerite’s concave surface. And the metepisternum and metepimeron are fused along the lateral margins of those sclerites; a derived character otherwise only observed in T. fieldianus. The microsculpture is distinctive, with the vertex covered with well-developed isodiametric to slightly transverse microsculpture, the pronotum covered with a dense transverse mesh, sculpticell breadth 3–4× length, and the elytral disc covered with dense transverse lines connected into a mesh over only portions of the surface.

Head capsule broad, eyes moderately convex, ocular ratio 1.35–1.48, eyes covering most of moderately protruded ocular lobe, ocular lobe ratio 0.90–0.92, horizontal diameter of eye crossing 20 ommatidia; antennae relatively stout, antennomere 9 length 1.67× maximal diameter; mandibles short, distance from anterior condyle to apex of left mandible 1.67× distance from condyle to lateroapical margin of labrum; mentum basal breadth 2.75× length from lateral apex to base, paramedial pits moderately deep; ligular apex truncate, two setae separated by four setal diameters, paraglossae elongate, extended beyond ligular apex more than distance from base to ligular margin. Pronotum broad, lateral margins convergent before minutely denticulate hind angles; basal margin lined with well-developed marginal bead, median base anterad bead longitudinally, shallowly strigose medially, minutely punctate laterally; median longitudinal impression with elongate lenticular pit at front of median base, narrow and shallow on disc, deep near anterior transverse impression; anterior transverse impression broad and shallow across width; anterior margin beaded only in lateral 1/3 to 1/4 each side, smooth medially; front angle protruded, subangulate mesally, rounded laterally; lateral seta separated from very narrow lateral marginal depression by two diameters of setal articulatory socket; laterobasal depression broadly subquadrate, central tubercle connected anteriorly to disc, mesal surface irregular near punctate median base. Elytra broadly hemiovoid, basal groove deep, slightly irregular at bases of striae, angle with lateral marginal depression obtuse-rounded; sutural stria deeply punctate on disc, the punctures isolated, smooth and moderately deep apically, the sutural striae of the two elytra bordering an upraised sutural callus at conjoined elytral apices; stria 8 deep mesad anterior and posterior series of lateral setae, shallow at midlength, variously interrupted there; lateral elytral setal series variable, with either: anterior series of 5 setae, 2 intermediate setae, and 6 apical setae; or 6 anterior setae, 2 intermediate setae, and 6 posterior setae; or 7 anterior setae, 2 intermediate setae, and 4 posterior setae; lateral marginal depression narrow anteriorly, broadened in apical half, lined with transverse sculpticells apically; subapical sinuation distinctly concave, elytral plica visible in dorsolateral view. Metepisternum slightly elongate, maximal width 0.82× lateral length. Abdomen with visible ventrites 3–6 broadly depressed laterally; suture between ventrites 1 and 2 nearly straight, ventrite 2 depressed within slight sinuation; anterior margins of ventrites 4–6 slightly depressed, but no punctures visible along suture; female apical abdominal ventrite with two setae each side, four shorter medial setae arranged in an apically broader trapezoid. Coloration of dorsal surfaces rufopiceous to piceous with silvery reflection; palpomeres, antennae, legs, and pronotal and elytral margins rufobrunneous; ventral body surface rufopiceous, though proepipleuron dark rufous, elytral epipleuron dark anteriorly and rufobrunneous posteriorly, and apical half of ventrite 6 rufobrunneous.

Male genitalia (n = 5). Aedeagal median lobe broad dorsoventrally, apex broadly downturned apicad ostium, with a small mucro on ventrobasal face of apex (Fig. 3E); internal sac with sclerotized spicular fields (Fig. 3E), including a ventrobasal spicular sclerite (Fig. 3G); short flagellum and flagellar sheath both present. Antecostal apodeme of abdominal IX extended distally, the extension ranging from broad and expanded distally (Fig. 3D), to narrow and parallel-sided (Fig. 3H). Right paramere varying slightly in length, the ventral surface lined with many (14–18) setae, the apex bearing two longer setae, and the apicodorsal surface lined with five to eight small setae (Fig. 6D, E); left paramere broadly rounded dorsally, with length varying in concert with right paramere (Fig. 6D, E), apex of variable length and breadth, bearing two longer apical setae and also small subapical setae of variable position and number.

Female reproductive tract (n = 1). Bursa copulatrix broader basally, with narrow apex, length twice breadth, compressed under microslide cover slip (Fig. 7C), surface relatively thick, translucent; spermatheca globose; spermathecal gland ovoid; spermathecal gland duct entering spermathecal duct basad spermathecal reservoir; basal gonocoxite 1 with apical fringe of two slender setae (Fig. 8C); apical gonocoxite 2 triangular, base moderately extended laterally, with two lateral ensiform setae, one dorsal ensiform seta, and two apical nematiform setae.

Holotype male, dissected (FMNH): CHILE: Malleco Prov., / Puren Nat. Mon. / Contulmo, 350 m, / 13.II.1985 // FMHD#85-1001, mixed / forest litter, S. &J. / Peck, P#85-118. / berlese / FIELD MUSEUM NAT. HIST. // dissection vial // Tropopterus / robustus / Liebherr ♂4 / J.K. Liebherr 2019 // HOLOTYPE / Tropopterusb / robustus / J.K. Liebherr 2019 (black-margined red label).

Paratype: Chile: Cautín Prov., Bellavista, Lago Villarrica, N shore, Berlese wet forest litter, 39°12.55'S, 72°08.14'W, 30-i-1986, Platnick & Schuh (CAS, 1), Villarrica, upper Flor del Lago, lot CH2002/3.41, 39°10.00'S, 71°59.07'W, 700 m el., 12-i-2003, Will (EMEC etoh, 5), Villarrica, 15 km S, Nothofagus woods, 39°24.62'S, 72°13.69'W, 14-ii-1993, Ward (CMNH, 2). Malleco Prov., M. N. Contulmo, Sendero Lemu Mau, Nothofagus obliqua-Eucalyptus cordifolia ++ w/ fern & bamboo understory, lot 1059, FMHD#2002-063, Berlese leaf and log litter, 38°00.74'S, 73°11.13'W, 410 m el., 8-xii-2002, Newton & Thayer (FMNH, 13), lot 1059, FMHD#2002-061, Flight intercept trap, 38°00.74'S, 73°11.13'W, 410 m el., 8-24-xii-2002, Thayer, Newton, Solodovnikov, Chani & Clarke (FMNH, 1), M. N. Puren, Contulmo, lot FMHD#85-1001, Berlese mixed forest litter, 38°00.90'S, 73°13.76'W, 13-ii-1985, S. & J. Peck (FMNH, 1), no other data, lot CH2002/3.124, Will (EMEC etoh, 1). Valdivia Prov., Huilohuilo, Neltume, 1 km WSW, Site B, Valdivian Rain Forest, leaf litter, sifting/photoeclector, 39°51'S, 71°57'W, 390 m el., 28-xi-1987, Ashworth, Figiseth & Maliscke (NDSU, 1), 7-i-1988, Ashworth, Figiseth & Maliscke (NDSU, 1), Pte. Blanco, Choshuenco, 8 km NW, Site A, Valdivian Rain Forest, leaf litter, sifting/photoeclector, 39°48'S, 72°05'W, 180 m el., 25-xi-1987, Ashworth, Figiseth & Maliscke (NDSU, 1).

The adjectival species epithet robustus is used to denote the broad body form of beetles of this species.

This species is distributed from latitude 38°S–39°51'S (Fig. 9D), within the Northern Valdivian entomofaunal province (O’Brien 1971). It has been recovered from Berlese samples of mixed forest litter, wet forest litter, or combined leaf and log litter. One specimen was collected in a ground-level collecting pan associated with a flight intercept trap. This species has been collected contemporaneously with the leiodid beetle Anaballetus chilensis (Newton et al. 2017: Chile: Cautín Prov., Bellavista, N shore Lago Villarrica, FMNH; and Chile: Malleco Prov., N. M. Contulmo, Sendero Lemu Mau, FMNH).

(n = 5). Both this species and T. duponchelii exhibit subparallel elytra with the sutural stria represented by a series of isolated punctures on the disc, and the second stria much reduced though still visible as a series of minute punctures (Fig. 1E, F). Individuals of T. canaliculus with more reduced second elytral striae could be confused with those of T. minimucro; however, that species is characterized by the absence of a basal elytral groove, the elytral surface smoothly convex inside the humeral tooth at the anterior end of the lateral marginal depression (compare Figs 1E, 2B). Compared to T. duponchelii, T. canaliculus can be characterized by the prosternum bearing a median, canaliculate depression that extends from the ventral face of the prosternal projection 2/3 the distance toward the anterior pronotal margin, whereas the prosternum of T. duponchelii is medially flattened to broadly depressed, not narrowly canaliculate. The two species can also be told by individuals of T. canaliculus exhibiting a narrower pronotum (MPW/PL = 1.20–1.25 versus 1.25–1.32 for T. duponchelii) and a glossier upper body surface. Tropopterus canaliculus has the vertex glossy with indistinct transverse sculpticells over portions of the surface, the pronotum also glossy, and the elytral disc glossy with indistinct transverse sculpticells visible near depressed portions of the surface such as the strial punctures, and minute micropunctures regularly distributed across the glossy surface. The dorsal microsculpture of T. duponchelii is much more developed, with both the pronotum and elytra bearing dense transverse lines that cause iridescence of the latter. In this species the pronotum is sparsely punctate in the laterobasal depressions and lateral portions of the median base, versus smooth in T. duponchelii, and the anterior pronotal margin is completely beaded, versus smooth and unmargined across the median half in T. duponchelii. The standardized body length = 5.8–7.5 mm; a smaller though not diagnostic range of sizes compared to T. duponchelii (below).

Head capsule broad basally, eyes moderately convex, ocular ratio 1.40–1.50; eyes covering much of abruptly protruded ocular lobe, ocular lobe ratio 0.85–0.90; horizontal diameter of eye crossing 25 ommatidia; antennomeres moderately elongate, length of antennomere 9 2.0× maximal diameter; mandibles moderately elongate, distance from anterior condyle to apex of left mandible 1.81× distance from condyle to lateroapical margin of labrum; mentum basal breadth 2.86× length from lateral apex to base, deep paramedial pits laterad base of mentum tooth; ligular apex broad, truncate, two setae separated by four setal diameters; paraglossae extended as far beyond ligular margin as distance from their base to ligular margin. Pronotal lateral margins convex, hind angles distinctly denticulate; basal margin with complete marginal bead, median base sparsely punctate across breadth, the punctures continuing across laterobasal depressions; median longitudinal impression with lenticular depression at front of median base, narrow and deep on disc; anterior transverse impression broad and shallow medially, traceable to front angles, anterior callosity broadly convex; anterior margin completely beaded, the bead continuous medially; front angle slightly protruded, right angled; lateral marginal depression very narrow in apical half, broadened from lateral seta to laterobasal depression; lateral seta separated from lateral marginal depression by the diameter of setal articulatory socket; laterobasal depression rugosely punctate, surface upraised in middle of depression; surface of proepisternum slightly irregular, as if beaten by a ball-peen hammer. Elytra broad, sides subparallel, humeri broad; basal groove deep, continuous from anterad parascutellar seta to tightly rounded humeral angle; parascutellar striole absent, sutural stria reaching basal margin mesad parascutellar seta; sutural stria a series of isolated punctures on disc, continuous and smooth apically, the striae of both elytra bordering upraised sutural callus associated with conjoined elytra; surface of elytra depressed mesad subapical and apical elytral setae; stria 8 continuous throughout length; lateral marginal depression broad, lined with transverse sculpticells; subapical sinuation broad, moderately excavated, elytral plica evident in dorsolateral view. Mesepisternum with broad vertical depression lined with ~8 punctures in 2 or 3 vertical rows; metasternal process narrowly rounded apically, apex broadly and sides more narrowly upraised; metepisternum somewhat elongate, maximal width 0.78× lateral length. Abdomen with ventrites 3–6 broadly depressed laterally, suture between ventrites 1 and 2 nearly straight, ventrite 2 depressed within slight sinuation; anterior margins of ventrites 4–6 depressed, intersegmental membranes punctate; apical female abdominal ventrite with 2 setae each side, plus a median group of two to four setae, subequal in length; if two nearly in line with lateral setae, if four aligned in an apically broader trapezoid. Coloration of dorsal body surface subtly tricolored, head and pronotum dark rufous, elytra darker, rufopiceous, elytral lateral marginal depressions translucent rufobrunneous; antennae, mouthparts, and legs rufobrunneous; ventral body surface rufopiceous, apex of elytral epipleuron slightly paler, apex of abdominal ventrite 6 narrowly paler to concolorous.

Male genitalia (n = 8). Aedeagal median lobe broad dorsoventrally, but with sclerotized ventral surface of shaft narrow and terminated in a narrow, smooth, spoon-like apex (Fig. 4A, C); internal sac with flagellum small, apical. Antecostal apodeme of abdominal IX broadly angulate distally, the short distal extension very broad (Fig. 4B, D). Right paramere of variable length, length not associated with length of left paramere (Fig. 6F, G), ranging from shorter and broader to more elongate with an attenuated apical extension, the ventral surface bearing from 8–20 setae, two longer setae present near or at apex; left paramere much broader basally, with apical extension ranging from an evenly narrowed projection (Fig. 6F) to a narrow, parallel digitiform extension (Fig. 6G), two longer setae present at apex, plus a variable number of subapical and ventral setae.

Female reproductive tract (n = 1). Bursa copulatrix columnar, broadly rounded apically, length 1.75× breadth, compressed under microslide cover slip (Fig. 7D), bursal walls thin, nearly transparent; spermatheca globose; spermathecal gland elongate-ovoid; spermathecal gland duct entering spermathecal duct basad spermathecal reservoir; basal gonocoxite 1 with one large apical fringe seta, a second small seta also present unilaterally (Fig. 8D); apical gonocoxite 2 falciform, base extended laterally, with two lateral ensiform setae, one dorsal ensiform setae, and two apical nematiform setae.

Holotype male dissected (CAS): Crest of Sierra / Nahuelbuta / Elev. 1200 m // W. of Angol / CHILE, I-3-51 // Ross and / Michelbacher / Collectors // dissection vial // Tropopterus / canaliculus / Liebherr ♂4 // HOLOTYPE / Tropopterus / canaliculus / J.K. Liebherr 2019 (black-margined red label). The type locality is in Malleco Prov., with geographic coordinates estimated to be 37°47.76'S, 73°02.27'W.

Paratypes. Chile: Arauco Prov., San Alfonso, Caramavida, above, 37°42.75'S, 73°09.00'W, 16–17-x-1969, Flint & Barria (NMNH, 1). Malleco Prov., P. N. Nahuelbuta, lot DRM 06.046, DRM DNA2200, 37°48.98'S, 73°05.7'W, 1312 m el., 7-i-2006, Maddison (OSAC, 1), Los Portones entrance, 4.5 km W, emergent Nothofagus spp., Araucaria aurucana, Chusquea understory, lot 975, pyr.-fogging old logs, 37°49.25'S, 72°59.82'W, 1300 m el., 7-ii-1997, Newton & Thayer (FMNH etoh, 1), Guarderia Pichinahuel, E of, Araucaria-Nothofagus dombeyi w/ Chusquea bamboo, lot 1054, in rotten logs, 37°48.20'S, 73°01.41'W, 1290 m el., 7-xii-2002, Clarke & Solodovnikov (FMNH, 5), lot 1054, pyr. fogging live Araucaria, 37°48.20'S, 73°01.41'W, 1290 m el., 24-xii-2002, Newton & Solodovnikov (FMNH, 1), lot 1054, FMHD#2002-094, Berlese debris under bark large Araucaria log, 37°48.20'S, 73°01.41'W, 1290 m el., 24-xii-2002, Newton & Solodovnikov (FMNH, 4), Los Portones entrance, 2.3 km W, Nothofagus dombeyi + ? antarctica, mostly open understory, lot 1057, pyr. fogging old Nothofagus logs, 37°49.41'S, 72°58.95'W, 1150 m el., 25-xii-2002, Newton, Thayer & Chani (FMNH, 6).

The species epithet canaliculus references the narrow, deep median prosternal depression present in these beetles. The epithet is to be treated as a noun.

This species' distribution lies near 38°S (Fig. 9E) in the Northern Valdivian entomofaunal province (O’Brien 1971). Most records are from forest-floor microhabitats, either by pyrethrin fogging of old, rotten Nothofagus logs, or in Berlese siftate from under bark of a large Araucaria log. One specimen was collected via pyrethrin spraying onto a live Araucaria trunk. This species was collected with Anaballetus chilensis at two sites (Newton et al. 2017: Chile: Malleco Prov., P. N. Nahuelbuta, 2.3 km W Los Portones entrance, FMNH, and P. N. Nahuelbuta, E of Guarderia Pichinahuel, FMNH).

Figure 10. 

Cladogram returned under all cladistic protocols described in text; tree length = 97, CI = 57, RI = 47, fast character optimization shown. Outgroup choice of Pharetis thayerae based on results in Liebherr (2020). Geographic region abbreviations after taxon name include: eastern Australia (EOZ); Santiagan entomofaunal province (San); Northern Valdivian entomofaunal province (NV); Southern Valdivian Entomofaunal province (SV).

(n = 5). To distinguish this species from T. canaliculus see that species’ diagnosis above. From all others, this species can be recognized by the medially, broadly flattened to broadly depressed prosternum, the depression not narrow and deep. The elytra bear a well-developed, dense, transverse-line microsculpture that results in a distinctly iridescent surface, whereas the vertex is covered with a shallow isodiametric mesh transversely stretched in parts, and the pronotum is covered with shallow transverse lines that result in only subtle iridescence. The eyes are moderately convex, ocular ratio = 1.37–1.46, with 20–25 ommatidia crossed by a horizontal diameter of the eye. The pronotal hind angles are obtuse and sharp, with the lateral margins slightly sinuate before the angles, and the pronotal median base and laterobasal depressions are smooth (Fig. 1F). The elytra are broad basally, with the basal groove well developed and meeting the lateral marginal depression at a distinct, obtuse angle, with a minute tooth projected posterad from that juncture. The mesepisternum is smooth throughout the dorsoventral depression of that sclerite. Standardized body length = 6.7–8.1 mm.

Male genitalia (n = 4). Aedeagal median lobe broad dorsoventrally to broadly rounded apex, the apex with broad, blunt mucro on ventrobasal surface (Fig. 4E, F); aedeagal internal sac with stout, serrate ventrobasal spicular sclerite and elongate, moderately sclerotized flagellum. Antecostal apodeme of abdominal IX rounded distally, the juncture of the lateral arms only slightly broader (Fig. 4G). Right paramere of variable length, ranging from short and broadly parallel-sided, to more elongate with an apical attenuated apex (Fig. 6H, I), ventral surface with about 13 setae in apical half, apex with two longer setae, and apicodorsal surface with several very small setae of variable position; left paramere varying in length in concert with right paramere, ranging from short and stout with a very short apical extension, to longer with a narrow, digitiform extension connected to body of paramere by semiflexible membrane, two longer apical setae present plus one to several short subapical setae.

Female reproductive tract (n = 1). Bursa copulatrix elongate, broader distally, length nearly 4× breadth, compressed under microslide cover slip (Fig. 7E); spermatheca an ovoid heart-shape; spermathecal gland elongate, fusiform; spermathecal gland duct entering spermathecal duct basad spermathecal reservoir; basal gonocoxite 1 with single apical fringe seta (Fig. 8E); apical gonocoxite 2 falciform, base extended laterally, with two lateral ensiform setae, one dorsal ensiform seta, and two apical nematiform setae.

Tropopterus duponchelii lectotype female (MNHN) hereby designated: S. Iago (handwritten on blue label) // MUSEUM PARIS / CHILI / Cl. Gay 1845 (grey label) // 9 45 (round blue label) // TYPE (red label) // Tropopterus / Duponchelii / Sol. Sn. Iago (handwritten white label) // LECTOTYPE / Tropopterus / duponchelii / Solier / des. Liebherr 2019 (black-margined red label). Tropopterus nitidus lectotype female (MNHN) hereby designated (pinned specimen with mouthparts mounted beneath on point): S. Iago (handwritten on blue label) // MUSEUM PARIS / CHILI / Cl. Gay 1845 (grey label) // 9 45 (round blue label) // TYPE (red label) // Tropopterus / nitidus Sol. / Sn. Iago (handwritten white label) // LECTOTYPE / Tropopterus / nitidus / Solier / des. Liebherr 2019 (black-margined red label). The types would have come into the Chaudoir Collection in 1876 directly from Philibert Germain (Ball and Erwin 1982). Given Chaudoir’s interest in mouthpart characters (Basilewsky 1982), and his synonymization of T. nitidus under T duponchelii in that year, it seems likely that the mouthpart dissection of the T. nitidus lectotype was made by Chaudoir himself.

Date/locality information, all specimens: Chile: Arauco Prov., Caramavida, Nahuelbuta (W), 37°40.99'S, 73°21.00'W, 750 m el., 25–31-xii-1953, Peña (MCZ, 2; MNHN, 1); Curanilahue, 37°28.58'S, 73°20.58'W, 10-xii-1967, Cekalov[ic] (MNHN, 1); San Alfonso, above Caramavida, 37°42.75'S, 73°09.00'W, 16–17-x-1969, Flint & Barria (NMNH, 1). Santiago Prov., Santiago, 33°26.75'S, 70°40.12'W, Solier (lectotypes T. duponchelii plus T. nitidus), 33°26.75'S, 70°40.12'W, Solier (MNHN, 1). Talca Prov., Altos de Vilches, 35°36.25'S, 71°04.30'W, 19-ix-1968, Ramirez (MNHN, 1), 26-i-1969, Valencia (MNHN, 1), 11-x-1971, Valencia (MNHN, 1). No data except “81”, Chaudoir Colln. (MNHN, 1).

This species is distributed from 33°27'S–37°41'S (Fig. 9F), spanning the Santiagan and Northern Valdivian entomofaunal provinces (O’Brien 1971). Specimens have been found by sifting litter in Valdivian rainforest with Nothofagus, via pyrethrin fogging of old Nothofagus logs, under logs and rocks, and by beating vegetation. Thus this species is most often encountered in ground-level microhabitats; however, there is evidence that the beetles can climb onto vegetation. Tropopterus duponchelii and the leiodid beetle Anaballetus chilensis are both known from Alto de Vilches, Talca Prov., Chile (Newton et al. 2017).

(n = 2). Although the pronota of all Tropopterus have the basal margin slightly undulated and medially convex, beetles of this species exhibit an exaggeration of this sinuation, with the base profoundly concave just mesad the acute hind angles in association with the deep laterobasal depressions (Fig. 2A). This Tropopterus also exhibits the largest body size; standardized body length of 8.2–8.4 mm larger than all but the largest individuals of T. giraudyi. The eyes are large in diameter though little convex, with an ocular ratio = 1.36 and a horizontal diameter crossing the eye intersecting 25–26 ommatidia. The sutural stria is punctate, the isolated punctures joined in part by indistinctly depressed strial connections, and the parascutellar striole is absent, the sutural stria vaguely continued to the elytral base as a broad depression. The outer elytral striae are progressively reduced, with striae 2 and 3 traceable as a series of minute, isolated punctures, and a very few minute punctures visible in the position of stria 4. Stria 8 just dorsad the lateral elytral setae is continuous throughout its length. As in T. minimucro and T. fieldianus, the elytral basal groove is absent; the elytral surface evenly and smoothly convex inside the anterior termination of the lateral marginal depression at the toothed humerus. Ventrally, the prosternum is broadly and deeply depressed from the prosternal process anterad 2/3 the distance to the pronotal anterior margin, and the mesepisternum is punctate, with ~18 punctures arranged in 2 or 3 vertical rows broadly distributed across its surface. Microsculpture of the vertex is an evident isodiametric mesh with sculpticells arranged in transverse rows in part. The pronotum is covered with a dense transverse mesh with sculpticells of breadth 3–4× length, complemented by transverse lines, and the elytra are covered with dense transverse lines producing iridescence.

Head capsule broad, ocular lobe little protruded; antennae moderately robust, length of antennomere 9 2.0× maximal diameter; mandibles elongate, but given large head, distance from anterior condyle to apex of left mandible only 1.80× distance from that condyle to lateroapical margin of labrum; mentum basal breadth 3.05× length from lateral apex to base, very deep paramedial pits laterad base of mentum tooth; ligular apex broad, truncate, two setae separated by four setal diameters; paraglossae extended beyond ligular margin slightly more than distance from their base to ligular margin. Pronotum moderately transverse, lateral margins distinctly sinuate anterad right to slightly acute hind angles; base with complete marginal bead, median base smooth medially, with approximately eight small punctures each side mesad laterobasal depression; median longitudinal impression with lenticular depression on median base, finely etched on disc; anterior transverse impression traceable medially, broad and shallow laterally; anterior margin smooth in medial 1/3, margined in lateral 1/3 each side; front angle protruded, subangulate; lateral marginal depression narrow from apex to lateral seta, widened in basal 1/3 of length; lateral seta separated from lateral marginal depression by diameter of setal articulatory socket; laterobasal depression margined medially by deep, sinuous impression, an upraised tubercle in middle of depression; proepisternum smooth dorsally, with broad irregular punctures near prosternal suture. Elytra broad basally, sides subparallel; humerus angulate with short extension of basal groove mesad angle; sutural stria with closely set yet isolated punctures on disc, punctures larger toward apex, but stria deep, narrow and smooth distad subapical sinuation; stria 8 deep and continuous throughout length; seven or eight anterior lateral elytral setae, six posterior setae; lateral marginal depression very narrow anteriorly, broader in apical half, lined there with transverse sculpticells; subapical sinuation broad and shallow, elytral plica visible in lateral view. Metepisternum equitrapezoidal, maximal width subequal to lateral length; metasternal process with a rounded apical knob, the lateral margins narrowly upraised. Abdomen with ventrites 3–5 longitudinally depressed laterally; suture between ventrites 1 and 2 sinuate, ventrite 2 depressed posterad sinuation; ventrites 4–6 depressed basally, the intersegmental membranes minutely punctate; female apical ventrite with two setae laterally each side and an elongate quadrangle of subequally-lengthed setae medially. Coloration of body dark, head, pronotal disc and elytra piceous, the latter with iridescent surface; antennae, mouthparts and legs brunneous; ventral surface piceous, pterothoracic and abdominal ventrites, and elytral epipleura iridescent, only apical 1/6 of apical abdominal ventrite paler, rufobrunneous.

Female reproductive tract (n = 2; females not dissected, only accessible gonocoxal characters described). Basal gonocoxite 1 with one apical fringe seta; apical gonocoxite 2 narrowly triangular, base not extended laterally, with two lateral ensiform setae, one dorsal ensiform seta, and two apical nematiform setae.

Holotype female (CAS): CHILE: Cautin Province, / Villarrica, 1250 m, trap / site 653, 15 – 29 Jan 1982 / Nothofagus domb.-pumilio / forest w/ Chusquea / A.F. Newton & M.K. Thayer // Tropopterus / trisinuatus / sp. nov. ♀1 photo / det. J.K. Liebherr 2019 // Tropopterus / Measured / Specimen #1 / det. J.K. Liebherr // HOLOTYPE Tropopterus / trisinuatus / J.K. Liebherr 2019 (black-margined red label). The type locality is Volcán Villarrica, 1250 m el.; geographic coordinates 39°22.8'S, 71°56.4'W (A.F. Newton, pers. comm.).

Paratype with identical data (CAS, 1).

The adjectival species epithet trisinuatus signifies the trisinuate basal pronotal margin that unique characterizes this species among those known.

This species is known only from the type locality in the Northern Valdivian entomofaunal province (O’Brien 1971). The two specimens were collected in a mixed forest of large Nothofagus dombeyi (Brisseau de Mirbel), N. pumilio (Poeppig and Endlicher), and Chusquea bamboo. The forest was near a recent lava flow, and the soil was thin. The specimens were collected from the ground-level microhabitat, either in a flight intercept trap catch pan, or in a leaf litter sift sample. The two types were collected at the same place and time as part of the type series of the oribatid mite Novonothrus puyehue Casanueva and Norton (1997).

(n = 5). These larger sized beetles – standardized body length = 7.2–7.9 mm – can be distinguished by the closely punctate sutural stria which becomes a fine, narrow impression on the elytral apex, and the broadly impressed and smooth stria 2 which is obsolete apically (Fig. 2B). The basal elytral groove is absent across most of the elytral base, though it extends for a short distance medially from the elevated humeral tooth at the base of the elytral lateral marginal depression. The pronotum is moderately transverse (MPW/PL = 1.27–1.37) and the pronotal base is smooth except for 5–8 shallow punctures mesad the laterobasal depression. The parascutellar striole is present as a broad smooth groove mesad the parascutellar seta, the groove not continuous with the base of the sutural stria. Ventrally the prosternum is broadly and deeply depressed medially from the prosternal process ventral face anterad 2/3 toward the prothoracic anterior margin, and the mesepisternum is irregularly punctate with 8–9 punctures in 2 or 3 vertical rows. The dorsal body surface bears well-developed microsculpture: 1, the vertex with an evident isodiametric mesh in transverse rows; 2, the pronotum with a dense transverse mesh, sculpticell breadth 2–3× length, accompanied by transverse lines over portions of the surface; and 3, the elytra with dense transverse lines resulting in iridescence.

Head capsule broad with moderately convex eyes, ocular ratio = 1.41–1.45, 25 ommatidia crossed by a horizontal diameter of eye; ocular lobes slightly protruded, their posterior margin obtusely meeting gena, ocular lobe ratio 0.85–0.89; antennae elongate, antennomere 9 length 2.30× maximal diameter; mandibles moderately elongate, distance from anterior condyle to apex of left mandible 1.76× distance from condyle to lateroapical margin of labrum; mentum basal breadth 2.8× length from lateral apex to base, very deep paramedial pits laterad base of mentum tooth; ligular apex broad, truncate, two setae separated by 4 setal diameters; paraglossae extended beyond ligular margin slightly more than distance from their base to ligular margin. Transverse pronotum with sides sinuate before acute, projected and denticulate hind angles; median base completely margined, base smooth medially anterad marginal bead, with ~8 minute punctures each side mesad laterobasal depressions; median longitudinal impression with deep, lenticular depression on median base, finely engraved on disc; anterior transverse impression broad and shallow medially, deeper laterally toward front angles; anterior margin smooth medially, margined in outer half of breadth each side; front angles only slightly protruded, rounded; lateral marginal depression very narrow in anterior 2/3 of length, gradually widened to hind angle; lateral setae separated from lateral marginal depression by diameter of articulatory socket; laterobasal depression subquadrate, a smooth tubercle upraised in middle of depression. Elytra broader in apical half, humeri narrowly rounded; lateral marginal depression ended blindly at humerus; parascutellar striole absent, sutural stria indicated by series of isolated punctures, those punctures more closely spaced in apical half, the stria smooth, narrow and deep on apex; subapical and apical setae together in depressed remnant of stria 7; stria 8 greatly reduced, broad and shallow among anterior lateral elytral setae, absent to shallow medially, and shallow, interrupted to deeper and continuous between setae of posterior series; lateral marginal depression moderately broad, lined with transverse sculpticells; subapical sinuation broad and shallow, elytral plica evident in lateral view. Metepisternum slightly elongate, maximal width 0.83× lateral length. Abdomen with ventrites 3–6 broadly depressed laterally; suture between ventrites 1 and 2 slightly sinuate, ventrite 2 depressed within sinuation; base of ventrites 4–6 depressed, no evidence of punctures associated with the intersegmental membranes; female apical ventrite with two long setae each side and four shorter setae in a more basally situated transverse row medially. Coloration of dorsal body dark rufous, antennae, mouthparts and legs rufobrunneous; ventral body surface also dark rufous, proepipleuron and elytral epipleuron concolorous to paler, rufobrunneous, apex of abdomen not paler.

Male genitalia (n = 10). Aedeagal median lobe broad dorsoventrally, the ostial opening narrowed to a rounded apex that bears a very small mucro on the ventrobasal surface (Fig. 5A, C); a large, distally serrate ventrobasal spicular sclerite present (Fig. 5C); flagellum elongate, associated with membranous flagellar sheath. Antecostal apodeme of abdominal IX broadly rounded distally, juncture of two lateral arms asymmetrically offset toward left side, the distal extension short. Right paramere elongate with narrow apical extension (Fig. 6J, K), ventral surface lined with 10–14 small setae, one or two larger setae at apex, and from one to several small setae on dorsoapical surface; left paramere broad basally, the apex ranging from a gradually narrow apex (Fig. 6J) to a very narrow, digitiform extension (Fig. 6K), two longer apical setae accompanied by several short setae.

Female reproductive tract (n = 1). Bursa copulatrix ovoid, expanded apically, length about 1.6× greatest breadth, compressed under microslide cover slip (Fig. 7F); spermatheca globose; spermathecal gland large, ovoid; spermathecal gland duct entering spermathecal duct basad spermathecal reservoir; basal gonocoxite 1 with apical fringe of one larger seta and one smaller seta (Fig. 8F); apical gonocoxite 2 broadly triangular, base moderately extended laterally, with two lateral ensiform setae, one dorsal ensiform seta, and two apical nematiform setae.

Holotype male, dissected (MCZ): PucaTrihue / Orsono Prov. / III-23-62 / CHILE Pena // dissection vial // Tropopterus / minimucro / Liebherr ♂2 / det. J.K. Liebherr 2019 // HOLOTYPE / Tropopterus / minimucro / J.K. Liebherr 2019 (black-margined red label). The geographic coordinates for the type locality are 40°32.10'S, 73°41.53'W.

Paratypes: Chile: Cautín Prov., Bellavista, Lago Villarrica, 39 12.55'S, 72 08.14'W, 250 m el., 8-i-2006, Will (EMEC, 4). Chiloé Prov., Degán, 10.3 km E, rte. W33, lot CH2006.18.1.1, 42°10.37'S, 73°36.72'W, 166 m el., 18-i-2006, Will (EMEC etoh, 1), Huillinco, 5.4 km S, Rio Terahuin, 42°43.12'S, 73°53.87'W, 36 m el., 22-i-2006, Will (EMEC, 2), P. N. Chiloé, Cucao, lot CH2002/3.53, 42°38.47'S, 74°07.00'W, 23 m el., 20-i-2003, Will (EMEC etoh, 3). Llanquihue Prov., Lago Chapo, near SE end, km 9.9 on road to Rollizo, Valdivian rainforest on steep slope, lot 989; pyr.-fogging old logs, 41°30.63'S, 72°23.98'W, 385 m el., 26-i-1997, Newton & Thayer (FMNH etoh, 1), P. N. Vicente Pérez Rosales, Volcán Osorno, SW slope ca. km 11 to La Burbuja, low Nothofagus dombeyi w/ mixed understory, lot 1005, FMHD #97-35, Berlese leaf and log litter, 41°07.91'S, 72°32.16'W, 1065 m el., 27-i-1997, Newton & Thayer (FMNH, 1), Ensenada, 9.2 km NE, on road to Petrohué, Valdivian rainforest with Nothofagus spp., lot 987, pyr.-fogging old logs, 41°10.20'S, 72°27.10'W, 125 m el., 28-i-1997, Newton & Thayer (FMNH etoh, 1), Volcán Osorno, SW slope c. km 11 to La Burbuja, low Nothofagus dombeyi w/bamboo & shrub understory, lot 1065, pyr.-fogging old mossy logs, 41°07.9'S, 72°32'W, 1090 m el., 15-xii-2002, Newton & Thayer (FMNH, 1). Osorno Prov., P. N. Puyehue, lot CH2002/3.192, 40°40.22'S, 72°10.07'W, 300 m el., 23-i-2003, Will (EMEC etoh, 1), lot CH2002/3.187, 40°40.22'S, 72°10.07'W, 300 m el. 23-i-2003, Will (EMEC etoh, 2), P. N. Puyehue, Anticura, Repucura Tr., lot P#85-113, FMHD #85-996, Berlese forest litter, 40°39.97'S, 72°10.47'W, 500 m el., 6-ii-1985, S. & J. Peck (FMNH, 2), Volcán Casablanca, E shore Lago Puyehue, Site 36, tundra-forest transition, 40°44'S, 72°10'W, 1270 m el., 18-xii-1977, Ashworth, Hoganson & Mooers (NDSU, 1), Osorno, 40°34.50'S, 73°07.00'W, xii-1977 (NMNH, 2). Valdivia Prov., Curiñanco, road to, 39°42.90'S, 73°23.77'W, 112 m el., 9-xi-2008, Will (EMEC, 1), La Union, 34 km WNW, lot P#85-36, FMHD #85-921, Berlese mixed forest litter, 40°15.00'S, 73°23.75'W, 700 m el., 17-xii-1984, S. & J. Peck (FMNH, 1), P. N. Oncol, Cerro Oncol trail, lot DRM 06-044, 39°41.89'S, 73°18.07'W, 525 m el., 10-i-2006, Maddison & Will (OSAC, 1; OSAC etoh, 1), lot DRM 06.045, 39°41.89'S, 73°18.07'W, 500 m, 11-i-2006, Maddison & Seago (OSAC etoh, 1), Sendero Oncol, 39°41.50'S, 73°18.25'W, 600 m el., 10-i-2006, Will (EMEC, 1), lot CH2006.10.i.2, 39°41.50'S, 73°18.25'W, 600 m el., 10-i-2006 (EMEC etoh, 2), 39°41.65'S, 73°18.86'W, 715 m el., 12-i-2006, Will (EMEC, 8), pitfall trap, 39°41.55'S, 73°18.86'W, 690 m el., 10-23-i-2006, Will et al. (EMEC, 2), 39°41.67'S, 73°18.25'W, 513 m el., 9-xi-2008, Will (EMEC, 2), 600 m el., 8-xi-2008, Will (EMEC, 1), Puerto Fui [sic Fuy], 14 km SE, Lago Pirehueico, Site G, Lenga Forest, Nothofagus pumilio, standard pitfall trap, 39 58'S, 71 48'W, 1230 m el., 5-xii-1987, Ashworth, Fugiseth & Maliscke (NDSU, 1), leaf litter, photoeclector, 39°58'S, 71°48'W, 1230 m el., 11-i-1988, Ashworth, Fugiseth & Maliscke (NDSU, 1), window/pitfall trap, 39°58'S, 71°48'W, 1230 m el., 11-i-1988, Ashworth, Fugiseth & Maliscke (NDSU, 1), standard pitfall trap, 39°58'S, 71°48'W, 1230 m el., 15-i-1988, Ashworth, Fugiseth & Maliscke (NDSU, 1).

The species epithet minimucro describes the very small mucro on the apex of the male aedeagal median lobe, that character amply diagnosing this species. The name is to be treated as a noun.

All records for this species are clustered from 39°13'S–42°39'S (Fig. 9H), straddling the transition between the Northern and Southern Valdivian entomofaunal provinces (O’Brien 1971). Collecting sites range from 23 m elevation on Isla Chiloé to 1270 m elevation in the forest-tundra transition zone on Volcán Casablanca (Ashworth and Hoganson 1987). Beetles have been found in Berlese siftate of mixed forest litter, leaf and log litter, and via pyrethrin fogging of old logs with or without moss. The species is broadly sympatric with the southern portion of the range of T. giraudyi. Moreover, both T. minimucro and T. giraudyi have been collected during the same collecting events four different times, suggesting intense sympatry at both macro- and microsympatric scales. The four identical collecting series include: Cautín Prov., Bellavista, Lago Villarrica, 39°12.55'S, 72°08.14'W, 250 m el., 8-i-2006, Will (EMEC); Valdivia Prov., P. N. Oncol, Mirador Pilocura, Sendero, 39°41.65'S, 73°18.86'W, 715 m el., 12-i-2006, Will (EMEC); Llanquihue Prov., P. N. Vicente Pérez Rosales, Volcán Osorno, SW slope c. km 11 to La Burbuja, low Nothofagus dombeyi w/bamboo & shrub understory, lot 1065, pyr.-fogging old mossy logs, 41°07.9'S, 72°32'W, 1090 m el., 15-xii-2002, Newton and Thayer (FMNH); and Llanquihue Prov., P. N. Vicente Pérez Rosales, Ensenada, 9.2 km NE on road to Petrohué, Valdivian rainforest with Nothofagus spp., lot 987, pyr.-fogging old logs, 41°10.20'S, 72°27.10'W, 125 m el., 28-i-1997, Newton and Thayer (FMNH). Tropopterus minimucro has been collected alongside the leiodid Anaballetus chilensis two times (Newton et al. 2017; Chile: Cautín Prov., Bellavista, N shore Lago Villarrica, FMNH; and Chile: Valdivia Prov., La Union, 34 km WNW, FMNH).

(n = 2). Like T. minimucro this species lacks the basal elytral groove and has the sutural stria punctate on the elytral disc. But unlike that species, T. fieldianus has both elytral stria 1 and 2 punctate subapically: stria 1 is deeply and narrowly impressed at the apex, whereas stria 2 is broadly, shallowly continuous there. The pronotum of this species is broad (MPW/PL = 1.37–1.39) and rather quadrate, broad basally with MPW/BPW = 1.18–1.25 (compared to the basally narrowed, more cordate pronotum of T. minimucro; MPW/BPW = 1.24–1.33). The eyes are very convex with 26 ommatidia intersected by a horizontal diameter, and an eye convexity ratio, EyL/EyD = 2.4. The pronotal median base is rugosely punctate mesad the laterobasal depressions, and the anterior pronotal margin is smooth medially and margined along the outer 1/3 of each side. Ventrally the prosternum is broadly, moderately depressed medially, the depression extended 2/3 the distance from prosternal process to anterior margin, with the depression shallow and broad between the coxae. The mesepisternum bears a single dorsoventral row of 4–6 punctures, and the metepisternum and metepimeron are fused laterally, the suture difficult to trace except mesally near the metacoxa. Dorsally the head is glossy with very shallow isodiametric sculpticells visible across the surface, and the pronotum and elytra bear dense elongate transverse sculpticells and transverse lines resulting in iridescence. Standardized body length = 6.7–7.8 mm.

Head capsule broad, eyes convex, ocular ratio = 1.42–1.44; antennae moderately elongate, antennomere 9 length 1.96× maximal diameter; mandibles elongate, distance from anterior condyle to apex of left mandible 1.96× distance from condyle to lateroapical margin of labrum; mentum basal breadth 3.0× length from lateral apex to base, very deep paramedial pits laterad base of mentum tooth; ligular apex broad, truncate, two setae separated by 4 setal diameters; paraglossae extended beyond ligular margin as far as distance from their base to ligular margin. Pronotum transverse, lateral margins nearly straight basally, briefly concave anterad right to slightly obtuse, denticulate hind angles; basal marginal bead complete, well developed medially; median base smooth; median longitudinal impression continued to basal marginal bead, lenticularly depressed near front of median base, finely inscribed on disc; anterior transverse impression obsolete medially, broad and shallow approaching front angle; front angles slightly protruded, obtuse-rounded; lateral marginal depression narrow in anterior half of length, evenly broadened from lateral seta to base; lateral seta separated from lateral marginal depression by diameter of setal articulatory socket. Elytra broad, lateral margins subparallel; parascutellar striole absent, sutural stria interrupted basally, terminated in broad, irregular depression surrounding parascutellar seta; stria 8 present near posterior setae of anterior lateral elytral setal series, shallow and interrupted near midlength, deep and continuous mesad posterior setal series; lateral marginal depression moderately broad from humerus to midlength, gradually narrowed to subapical sinuation; subapical sinuation broadly concave, moderately deep, plica well evident in dorsolateral view. Metepisternum slightly elongate, maximal width 0.83× lateral length. Abdomen with ventrites 3–6 longitudinally depressed laterally; suture between ventrites 1 and 2 slightly sinuate laterally, ventrite 2 depressed within slight sinuation; abdominal ventrites 4–6 depressed basally, minutely strigose along intersegmental membranes; male apical abdominal ventrite with two setae each side, in one specimen median two setae more basally positioned, in the other two bilateral pairs of apical setae complemented by three shorter medial setae in the position usually observed in female specimens. Coloration (based on apparently, slightly teneral individuals) paler, head capsule rufopiceous, pronotum and elytra rufobrunneous; legs paler, rufoflavous; thoracic and abdominal ventrites brunneous, proepipleuron and elytral epipleuron paler, rufoflavous.

Male genitalia (n = 2). Aedeagal median lobe broad dorsoventrally with broadly rounded apex, a minute mucro on the ventrobasal margin of the apex (Fig. 5E); internal sac armature including flagellum and flagellar sheath. Antecostal apodeme of abdominal IX broadly rounded distally, with juncture of two lateral arms asymmetrically offset toward left side, distal extension broadly rounded (teneral specimen). Right paramere elongate, broader near midlength, narrowed evenly to apex, ventral surface lined with 16 small setae, two larger setae at apex, three subapical setae, and two very small setae on dorsal surface; left paramere very broad for much of length, terminated apically by a evenly narrowed projection with two larger apical setae, a third smaller subapical seta, plus several very small setae on apical process or ventral margin.

Holotype male (FMNH), point mounted with left mesotarsomeres glued to point: CHILE: Osorno Prov., 3 / km S Maicolpue, Bahia / Mensa, 200 m, / 21.XII.1984 // FMHD#85-933, mixed forest litter, S. &J. / Peck, P85- 48 / berlese / FIELD MUSEUM NAT. HIST. // Tropopterus / Measured / Specimen #1 / det. J.K. Liebherr 2019 // dissection vial // Tropopterus / fieldianus / Liebherr ♂1 / det. J.K. Liebherr 2019 // HOLOTYPE / Tropopterus / fieldianus / J.K. Liebherr 2019 (black-margined red label).

Paratype: CHILE: Valdivia, 35 km WNW La Union, 7.xi.1985, 700m el., Mixed forest, S. Peck, P#85-114, FIELD MUSEUM (FSCA, 1)

The species epithet fieldianus combines the noun field with the adjectival ending –anus, thereby signifying that this species belongs to the Field Museum. This “belonging” is based on the Field Museum’s institutional dedication to Coleoptera systematics signified by a long succession of beetle curators: John E. Liljeblad, Rupert L. Wenzel, Henry S. Dybas, Harry G. Nelson, Larry E. Watrous, Steve Ashe, Alfred F. Newton, and Margaret K. Thayer.

This species is known only from two localities (Fig. 9I) distributed near latitude 40°S in the northern portion of the Southern Valdivian entomofaunal province (O’Brien 1971). It has been recovered from Berlese siftate of mixed forest litter. At the La Union site in Valdivia Prov., it was collected alongside the leiodid species Anaballetus chilensis (Newton et al. 2017).