Lithocharodes bicornis, Irmler, 2021

Irmler, Ulrich, 2021, The Neotropical species of the genus Lithocharodes SHARP, 1876 (Coleoptera: Staphylinidae: Staphylininae: Xantholinini), Beiträge Zur Entomologie = Contributions to Entomology 71 (1), pp. 29-85 : 36

Lithocharodes bicornis spec. nov.

Figs 11 a-d, 44 O, 49 C

Type material: male, holotype: Peru, Huanuco, Llullapichis, Panguana Station (74°56'W, 9°37'S), floodplain forest, sifted litter, male, 25.3.1975, leg. W. Hanagarth ( UIC) .

Diagnosis: Lithocharodes bicornis closely resembles L. sordida in size, colouration, punctation of the head and even in the structure of the aedeagus and the shape of the paramere. Males are easily to separate by the structure of sternite and tergite VII. The pair of spines at the posterior margin of sternite VII of L. bicornis is unique in the genus, although many Lithocharodes species have paired processes at sternite VII but these are broader and more teeth-like.

Description: Length: 4.5 mm. Colouration: Brown; head and elytra darker brown than pronotum.

Head: 0.77 mm long, 0.67 mm wide; eyes moderately large; not prominent; postocular sides divergent; 2.5 times as long as eyes; posterior angles widely rounded to neck; posterior margin slightly emarginate in front of neck; interantennal furrows extremely weak; setiferous punctation deep and dense; on average, interstices half as wide as diameter of punctures; on anterior vertex denser than on posterior vertex; surface without microsculpture; glossy. Antennae with first antennomere reaching half-length of head; second and third antennomere each conical and approximately twice as long as wide; subsequent antennomeres wider than long and increasing in width; fourth antennomere 1.5 times as wide as long; tenth antennomere twice as wide as long; all antennomeres pubescent. Pronotum: 0.87 mm long, 0.60 mm wide; widest in anterior third; anteriad, conically narrowed toward neck; posteriad, slightly narrowed in middle third; nearly parallel in posterior third; posterior angles shortly rounded; posterior margin nearly straight; setiferous punctation deep and dense; on average, interstices between punctures half as wide as diameter of punctures; wide midline impunctate; midline wider in anterior half than in posterior half; irregular row of punctures adjacent to impunctate midline with approximately 20 punctures; surface without microsculpture; glossy. Elytra: 0.83 mm long, 0.69 mm wide; humeral angles sub-rectangular; sides slightly divergent posteriad; posterior angles subrectangular; posterior margin nearly straight; setiferous punctation as dense and deep as on pronotum but partly coriaceous; surface with weak irregular microsculpture; less shiny than pronotum. Abdomen with dense setiferous punctation; punctures distinctly finer than on fore-body; sternite VII of male with concavely emarginate posterior margin; posterior margin with two fine spines and several thick setae; tergite VII of male with straight posterior margin; short rectangular process with pair of teeth at each angle in middle of posterior margin. Meso- and metatibia with one subapical ctenidium each. Aedeagus oval; in anterior half sub-rectangular; endophallus apically with three long and thick teeth; posterior part sack-like; covered by minute teeth; paramere broad; spoon-like; at apex with transparent inner lobe; several long, fine setae and several short and curved setae.

Etymology: The species epithet is a combination of the Latin words bi (meaning two) and cornis (meaning horn) and refers to the spectacular spines at the posterior margin of sternite VII of male.

Figures

Fig. 8–12: L.-hanagarthi-group and L.-sordida-group:Lithocharodes boliviana (8), L. hanagarthi (9), L. obscura (10), L. bicornis (11), L. sordida (12); aedeagus (a), paramere (b), sternite VII of male (c), tergite VII of male (d); scale bare: A – D: 0.2 mm; B: 0.1 mm.