Research Article |
Corresponding author: Tomáš Lackner ( lackobelansky@mac.com ) Academic editor: Harald Letsch
© 2016 Tomáš Lackner.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Lackner T (2016) Satrapister nitens Bickhardt, 1912: redescription and tentative phylogenetic placement of a mysterious taxon (Coleoptera, Histeridae, Saprininae). Deutsche Entomologische Zeitschrift 63(1): 1-8. https://doi.org/10.3897/dez.63.6363
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The monotypic genus Satrapister Bickhardt, 1912 is redescribed and figured. Its tentative position in the recently performed phylogeny of the subfamily, inferred from a new analysis based on the available morphological characters is discussed. Lectotype of Satrapister nitens Bickhardt, 1912 is designated.
Coleoptera , Histeridae , Saprininae , Satrapister , phylogeny
Satrapister nitens Bickhardt, 1912 was described more than a hundred years ago by Bickhardt, one of the leading experts of the histerid taxonomy from the first half of the 20th century, as the type species of the monotypic genus Satrapister Bickhardt, 1912. The species was described based on two specimens collected by A. Reclaire in Göttingen (Germany) in guano, originating from Peru and became a mystery practically since its description, both for its uncertain origin, biology and morphology. Its taxonomic placement was only briefly discussed by
The lectotype specimen was soaked in water overnight, removed from its original mounting card, cleared from dust and remaining glue with 70% ethanol and mounted on a triangular point for observation. Other specimens were observed under binocular microscope. Colour images were made by F. Slamka (Bratislava, Slovakia). Measurements were made by ocular micrometer. Body part terminology follows that of
APW width between anterior angles of pronotum
EL length of elytron along elytral suture
EW maximum width between outer margins of elytra
PEL length between anterior angles of pronotum and apices of elytra
PPW width between posterior angles of pronotum.
Analytical methods. Cladistic analyses were based on the external structures and male genitalia. In total, 95 morphological characters (see
Satrapister
Bickhardt, 1912: 231. Type species Satrapister nitens Bickhardt, 1912: 232, by monotypy. Satrapister: Bickhardt (1926): 81, 82, table 4, fig. 27;
Very small elongate-oval non-metallic Saprininae beetle with sparsely punctate dorsum and reduced dorsal elytral striae. Venter of body with sparse microscopic setae; carinal prosternal striae very reduced or obsolete; lateral prosternal striae divergent anteriorly; prosternal foveae absent; apex of prosternal process with sulcus. Meso- and metaventrite almost impunctate; lateral disc of metaventrite + metepisternum punctuate and setose. Mandibles of unequal length, left mandible slightly longer than right. Eyes completely flattened, reduced, invisible from above. Sensory structures of antenna in form of a single stipe-shaped vesicle situated under round sensory area on internal distal part of the antennal club complemented by another round sensory area. Protibiae with 9-11 low teeth topped by rather long, curved thin amber denticles.
As I am not familiar with most of the South American taxa of the species-rich genus Euspilotus, I hesitate to provide a clear-cut differential diagnosis of the genus Satrapister. It is, however, most readily distinguishable from the majority of the South American species of the subfamily that I am familiar with by its elongate-oval body form, reduced and flattened eyes and almost complete lack of elytral striation.
Unknown, the type specimens were found in guano originated from Peru; reduced eyes can indeed indicate its inquilinous habits. The other three specimens do not carry any biological data on their labels.
Satrapister
nitens
Bickhardt, 1912: 232;
Lectotype (designated here), ♂, glued on its side on a triangular mounting point, except for pretarsus all other tarsi missing, both antennae, left mandible missing, both hind legs missing, propygidium and pygidium dismembered, separated from the rest of the abdominal segments and glued to the mounting card separately from the specimen, right elytron wholly longitudinally cracked, with dismembered male genitalia glued also to the same mounting card as the specimen, with following labels: “in Peru guano” (written); followed by: “Type” (brick-red label, written); followed by: “Satrapister / nitens / n.gen. n. sp. / Bickh” (dark green, barely legible written label); followed by: “Coll. Veth” (printed); followed by: “Type” (red label, printed); followed by: “LECTOTYPE / Satrapister nitens / Bickhardt, 1912 / des. T.
PERU: 2 ♂♂, Isla Don Martín, 15.ii.1955, Coll. M. Peña (MUSM). 1 ♀, Isla de Pescadores [=Isla Grande], 5.viii.1934, collector illegible (SENASA).
Body (Figs
Pronotal hypomeron punctate, with distinct regular microscopic setae, lateral pronotal margins (Fig.
Elytral epipleuron with several irregular wrinkles and few punctures, otherwise smooth; marginal epipleural stria fine, complete, marginal elytral stria carinate and complete; apical elytral stria obliterated on half its length. Oblique humeral stria deeply impressed on basal elytral fourth; in one specimen a median fragment of inner subhumeral stria as well as a basal fragments of elytral striae 1-2 present; in rest of specimens all other elytral striae, except for short basal fragment of fourth dorsal elytral stria that is basally connected to almost complete sutural elytral stria completely lacking. Elytral disc with scattered punctures separated by several times their diameter.
Propygidium and pygidium with punctuation similar to the elytra, but punctures deeper and denser, separated approximately twice their diameter.
Prosternal process (Fig.
Mesoventrite (Fig.
First visible abdominal ventrite vaguely striate laterally, disc almost glabrous, only with scattered microscopic punctuation.
Legs: protibia slightly dilated, with 9–11 low teeth topped by rather long thin curved denticles diminishing in size in proximal direction, protarsal groove shallow, protibial spur short and stout, growing out from apical protibial margin, further characters of protibia not examined. Mesotibia on outer margin with a row of low teeth topped by long, slender amber-coloured denticles, setae of outer row dense and rather long; setae of median row finer and shorter; on anterior face of mesotibia another row of shorter dense amber denticles present, mesotibial spur stout and well-developed; metatibia slightly longer than mesotibia, denticles on outer metatibial margin more closely-set; metatarsal claws short, bent, about half-length of terminal metatarsal segment; other characters of legs not examined.
Male genitalia: eighth sternite (Figs
4 Satrapister nitens Bickhardt, 1912 LECTOTYPE, eighth sternite and tergite, ventral view 5 ditto, dorsal view 6 ditto, lateral view 7 Satrapister nitens Bickhardt, 1912 LECTOTYPE, ninth tergite, dorsal view 8 Satrapister nitens Bickhardt, 1912 LECTOTYPE, tenth tergite, dorsal view 9 Satrapister nitens Bickhardt, 1912 LECTOTYPE, ninth tergite, lateral view 10 Satrapister nitens Bickhardt, 1912 LECTOTYPE, spiculum gastrale, ventral view 11 ditto, lateral view 12 Satrapister nitens Bickhardt, 1912 LECTOTYPE, aedeagus, dorsal view 13 ditto, lateral view
Results of the tree reconstruction analyses are shown in Figure
The genus Satrapister was, due to its unavailability not included in my phylogeny of the subfamily, which was based on the morphological characters of the adults alone (
A The strict consensus of 1026 equally parsimonious trees; TL = 701, CI: 0.29, RI: 0.57, of the newly-performed analysis showing the position of Satrapister Bickhardt, 1912 and Phoxonotus Marseul, 1862, respectively. Double-digit numbers above branches show the percentage of bootstrap support (bootstrap values below 50% are not shown); single-digit numbers at nodes show Bremer indices for the nodes B Section of the cladogram of
The position of the species Satrapister nitens on the cladogram, in the same grade as P. tuberculatus must, due to the low support of the most branches, be regarded as preliminary and tentative. Its morphological characters are a mix of plesiomorphic (e.g. absent supra-orbital striae) and apomorphic ones (e.g. the presence of only a single, stipe-shaped vesicle or the 8th sternite and tergite of male genitalia fused laterally).
Based on the reduced eyes as well as its presence in guano there is room for speculation that S. nitens is indeed an inquilinous species. The incomplete biological data and lack of larval and/or molecular characters of this species considerably blur the picture of its exact allegiance with the rest of the subfamily.
Thanks are due to the curators of the above-mentioned institutions that loaned me the two type specimens as well as to Gerardo Arriagada (Santiago de Chile, Chile) who sent me the three specimens of S. nitens collected in the 20th century. Andreas Pütz (Eisenhüttestadt, Germany) as well as Michael Geiser (London, UK) are being thanked for their help with German language. This research received support from the SYNTHESYS Project http://www.synthesys.info/, which is financed by the European Community Research Infrastructure Action under the EP7 Integrating Activities Program as well as it received support from the grant of the Faculty of Forestry and Wood Sciences, Specific research, grant n. B06/15, Czech University of Life Sciences Prague, Czech Republic. I thank Slawomir Mazur (Warsaw, Poland), Alexey K. Tishechkin (Washington D.C., USA) and Lúcia M. Almeida (Curitiba, Brazil) who reviewed this manuscript and suggested numerous corrections. Special thanks to Harald Letsch, Editor at Deutsche Entomologische Zeitschrift for his valuable comments on the manuscript and editorial work.