Squamiger, Hlaváč, Peter & Baňař, Petr, 2016

Hlaváč, Peter & Baňař, Petr, 2016, The Pselaphinae (Coleoptera: Staphylinidae) of Madagascar. V. Description of Squamiger elegans gen. et sp. nov. from Central Madagascar, Zootaxa 4127 (2), pp. 393-400 : 394-397

Squamiger gen. nov.

( Figs 1–22 )

Type species: Squamiger elegans sp. nov. (present designation).

Diagnosis. Small clavigerine of the tribe Clavigerini , subtribe Clavigerodina, with five-segmented antennae, scape very short, completely hidden in antennal cavity, terminal antennomere (V) inserted in antennomere IV, both subequal in length, antennae somewhat shorter in female, with distinctly shorter terminal segment. Setae on lateral and dorsal body faces broad and flatened, squamose. Head with well-defined occipital constriction. Elytra, base of abdomen (dorsally) and first visible paratergite with three pairs of trichomes.

Description. Body ( Fig. 1 ) reddish-brown, antennae and legs slightly lighter. Setae on lateral and dorsal parts of body except abdomen broad and squamose. Head elongate, more than twice as long as wide, widest across eyes ( Fig. 2 ), eyes large, about as long as temples, rostrum strongly projecting. Head capsule clearly demarcated by conspicuous occipital contriction from neck region ( Figs 12 , 14 ), antennal cavity broad and deep. Antennae ( Fig. 12 ) with five antennomeres, slightly longer than head in males, shorter than head in females. Terminal antennomere (V) inserted into IV, both subequal in length, antennomeres I–IV with the same cuticular surface as on rest of the head, with somewhat broadened setae, terminal antennomere roughly wrinkled, with normal, long, slender setae ( Figs 6 , 12 ). Ventral part of head with tentorial pits distinctly separated. Pronotum ( Fig. 3 ) pentagonal, wider and shorter than head. Scutellum not visible. Elytra large, at suture slightly shorter than abdomen and about twice as long as pronotum, smooth, humeri inconspicuous, lacking foveae, each elytron with seven dorsal rows of setae. Posterior elytral margins with robust trichomes. Dorsum of abdomen shiny, composite tergite (IV–VI) shorter than elytra, with deep and large basal impression and two lateral trichomes located opposite tergal trichomes. Tergites VII and VIII very short, barely visible in dorsal view. First visible paratergites with long trichomes. Prosternum ( Fig. 15 ) with long prosternal process narrowly separating procoxae, mesoventrite and metaventrite confluent, shiny, both with fine longitudinal wrinkles on their lateral parts. Mesoventrite in middle with prominent keel ( Fig. 9 ) separating, together with metaventral anterior process, mesocoxae. Metaventrite with sharp median projection pointing posteroventrally ( Fig. 9 ). Metacoxae broadly separated by very wide and short posterior metaventral process ( Fig. 16 ). First visible sternite (III) about half as long as second sternite, second visible sternite (IV) longest, about as long as sternites V–VIII combined, with two well-defined lateral foveae, its lateral fourths between foveae and lateral margins conspicuously wrinkled ( Fig. 20 ). Legs short, tibiae pedunculate, mesotibiae with minute thorn in males ( Fig. 19 ), femora clavate.

Aedeagus ( Figs 21−22 ) symmetrical, parameres fused to median lobe, basal bulb semispherical, distinctly shorter and well-delimited from slender, long and at apex narrow apical lobe, dorsal diaphragm large, oval.

Sexual dimorphism. Males smaller, bearing sexual characters on mesotibiae and antennae.

Differential diagnosis: Squamiger is placed in the subtribe Clavigerodina on the basis of the combination of following character states: 1) humeral angles of elytra rounded, not projecting laterally, 2) lateral margins of pronotum slightly convergent at base, posterior margin distinctly narrower than elytra, 3) head capsule demarcated from neck region by conspicuous occipital constriction, 4) head lacking median longitudinal sulcus, flat. Squamiger differs from all known genera of Clavigerodina by the presence of broad, squamose setae on various body parts as well as by a unique connection of antennomeres IV and V.

Etymology. The new generic name, Squamiger , meaning scale-bearing, is a name in apposition, derived from the Latin squam -a (= scale) and Claviger , the type genus of the group. Gender masculine.

Distribution. Central Madagascar.

Figures

FIGURES 1 – 5. Squamiger elegans gen. et sp. nov. Hlaváč & Baňař, male paratype: 1, dorsal habitus; 2, head, dorsal view; 3, pronotum, dorsal view; 4, detail of scale-like setae on pronotum; 5, elytra, dorsal view. Scale bars in mm.

FIGURES 6 – 9. Squamiger elegans gen. et sp. nov. Hlaváč & Baňař, male paratype: 6, detail of antennomere V, anterior view; 7, elytral and abdominal trichomes; 8, laterodorsal habitus; 9, lateroventral habitus. Scale bars in mm.

FIGURES 10 – 12. Squamiger elegans gen. et sp. nov. Hlaváč & Baňař, male paratype: 10, abdomen and apex of elytra, lateral view; 11, sternite IV, fovea and wrinkled area; 12, head, lateral view. (III—third antennomere; IV—fourth antennomere; Vfifth antennomere; bc — buccal cavity; gp — gular plate; occ — occipital constriction; pd — pedicel; sc — scape). Scale bars in mm.

FIGURES 13 – 16. Squamiger elegans gen. et sp. nov. Hlaváč & Baňař, male paratype, ventral view: 13, habitus; 14, head; 15, prothorax, ventral view; 16, fused meso- and metaventrite. (bst — basistipes; cd — cardo; cl — clypeus; gp — gular plate; lb — labrum; md — mandible; mn — mentum; occ — occipital constriction; plp — palpomere; tp — tentorial pits). Scale bars in mm.

FIGURES 17 – 20. Squamiger elegans gen. et sp. nov. Hlaváč & Baňař, male paratype: 17, head, anterior view; 18, head, anteroventral view; 19, left middle tibia, inner view; 20, abdomen, ventral view. (bc — buccal cavity; cd — cardo; cl — clypeus; fr — frons; lb — labrum; md — mandible; mn — mentum; pd — pedicel; plp — palpomere; sc — scape). Scale bars in mm.

FIGURES 21 – 22. Squamiger elegans gen. et sp. nov. Hlaváč & Baňař, male paratype, aedeagus: 21, dorsal view; 22, lateral view. Scale bars in mm.