Drilorhinus, Kovalev & Kirejtshuk & Shapovalov, 2019

Kovalev, Alexey V., Kirejtshuk, Alexander G. & Shapovalov, Andrey M., 2019, Drilorhinus, a new genus of the family Drilidae Lacordaire, 1857 (Coleoptera: Elateroidea) from Iran, Zootaxa 4577 (1), pp. 187-194 : 188-189

Drilorhinus gen. nov.

Type species: Drilorhinus klimenkoi sp. nov.

Etymology. The name of the new genus is formed from the generic name “ Drilus ” and Greek “ῥίς, ῥινός” (nose, snout). Gender masculine.

Composition. The type species only.

Diagnosis. Head somewhat wider than anterior margin of pronotum. Frons between antennal insertions strongly protruding forward and forming long subtriangular projection, covering mouthparts from above; antennal insertions located at base of sides of this projection. Antennae pectinate. Labrum small and slightly transverse, freely attached and fully exposed. Mandibles comparatively short and stout, moderately curved, with angularly curved outer margin. Pronotum slightly transverse, subtrapezoid, with lateral ridge distinct only in posterior half. Elytra shortened and somewhat divergent, covered with rough rugose-granulate sculpture. Prosternum with prosternal process short and widely rounded at apex. Mesoventrite V-shaped, with anterior margin deeply and widely emarginate.

Comparison. A strong projection of the anterior part of the frons between antennal insertions distinguishes the new genus from all known genera of Drilidae ( Drilus A. Olivier, 1790 ; Flabelloselasia Kundrata et Bocak, 2017; Kupeselasia Kundrata et Bocak, 2017; Lolosia Kundrata et Bocak, 2017; Malacogaster Bassi, 1834 ; Microselasia Kundrata et Bocak, 2017; Selasia Laporte de Castelnau, 1836 , and Wittmerselasia Kundrata et Bocak, 2017). Drilorhinus gen. nov. is most similar to Malacogaster in sharing the subtrapezoidal pronotum with shortened lateral ridge, shortened elytra (reaching only the base of abdominal segment 6), and V-shaped mesoventrite with deeply emarginate anterior margin, but the latter genus differs from Drilorhinus gen. nov. in the serrate antennae, very transverse labrum, widely separated falcate mandibles, subparallel-sided pronotum, and shape of the parameres. Drilus resembles the new genus in the shape of the mesoventrite, however, in contrast to the new genus, Drilus demonstrates the convex lateral pronotal margins with almost complete lateral ridges and not shortened elytra. Selasia differs from Drilorhinus gen. nov. in the concave anterior margin of the mesoventrite, elytra that are not shortened, and flabellate antennae. In addition to the above-mentioned diagnostic characters of Drilorhinus gen. nov., the anterior part of the head of the new genus differs from the Afrotropical members of this family (Flabelloselasia Kundrata et Bocak, 2017; Kupeselasia Kundrata et Bocak, 2017; Lolosia Kundrata et Bocak, 2017; Microselasia Kundrata et Bocak, 2017 and Wittmerselasia Kundrata et Bocak, 2017, known to the authors after Kundrata & Bocak, 2017) in the shortened elytra, and also from Flabelloselasia, Microselasia and Wittmerselasia in the pectinate antennae (not flabellate), and from Kupeselasia and Lolosia in the much larger body and pectinate antennae (not serrate).

Description. Head slightly hypognathous, slightly wider than anterior margin of pronotum, dorsally convex, frons between antennal insertions strongly protruding forwards and forming long subtriangular projection, antennal insertions located at base of sides of projection, mouthparts completely concealed observing head from above; upper plane of this projection nearly horizontal and flattened, lateral planes strongly converging toward cariniform emarginate anterior edge, frontal plane strongly inclined ventroposteriorly toward emarginate anterior margin of epicranium ( Figs 1 , 2, 7 ). Eyes medium-sized, hemispherically prominent and rather coarsely facetted; frontal distance between eyes 1.85 times as great as eye diameter. Labrum small and slightly transverse, sclerotized, free and completely exposed, with anterior margin slightly concave ( Fig. 2 ). Mandibles moderately separated, comparatively short and robust, moderately curved, with short shining apical region and sharp subapical tooth, apex acute, outer margin angularly curved ( Fig. 2 ). Maxillary palpi short and slender, tetramerous, palpomere 1 short and wide; palpomere 2 about 1.5 times as long as wide; palpomere 3 short, about as long as wide; apical palpomere elongate, about twice as long as palpomere 3, obliquely truncate at apex ( Fig. 4 ). Labium short; labial palpi trimerous, with apical palpomere subacute ( Fig. 5 ). Antennae 11-segmented, pectinate, covered with moderately dense setae ( Fig. 3 ).

Pronotum slightly transverse, subtrapezoidal, widest at base; anterior margin slightly concave medially; sides subrectilinear: slightly diverging posteriorly in anterior half and scarcely convex before posterior angles; posterior margin slightly bisinuate and nearly straight medially. Anterior angles obtuse; posterior angles subacute and narrowly rounded at apex. Lateral carina separating pronotum from prohypomeron distinct in posterior half and obliterated anteriorly ( Fig. 7 ). Prohypomeron carinate sublaterally; prosternal suture short. Prosternum transverse; chin-piece short, with anterior margin widely emarginate; prosternal process very short and widely rounded at apex ( Fig. 6 ).

Scutellum elongate, flattened, subtriangular, with concave sides and blunt apex. Elytra elongate, each gradually narrowing posteriorly, reaching only the base of abdominal segment 6, divergent, adjacent to each other only at its basal third, elytral apices separately rounded; elytral striae indistinct; each elytron somewhat raised along suture, with weakly expressed arcuate costa running from humeri towards apices and short oblique weak keel in scutellar region. Integument uniformly rugose-granulate and dull.

Mesoventrite widely V-shaped, with frontal margin widely and deeply emarginate; mesoventral cavity shallow, with weakly defined walls. Mesocoxal cavity open to both mesepimeron and mesepisternum. Metaventrite large, subtrapezoidal.

Legs slightly narrow and compressed; coxae robust; trochanters slender, elongate, slightly widened apically, obliquely attached to femora. Tarsi moderately long; tarsomeres 1 and 2 subequal in length; tarsomere 3 slightly shorter than preceding ones, about 1.5 times longer than tarsomere 4; tarsomere 4 shortest, extended ventrally; apical tarsomere slender and elongate, about 2.5 times as long as tarsomere 4; claws simple, slender, slightly curved, each with one long seta at base.

Abdomen soft and slender; penultimate ventrite subtruncate at apex. Tergite 9 shallowly concave at apex; tergite 10 subquadrangular and widely rounded at apex. Sternite 9 about 1.8 times as long as wide, slightly notched at base and with widely rounded apical margin, its apex finely punctate and sparsely setose.

Male genitalia trilobate ( Figs 9–11 ); phallobase robust, slightly longer than wide, basally narrowed; penis (median lobe) robust, longer than parameres and slightly longer than phallobase, moderately curved in lateral view, basally with pair of short divergent apophyses, dorsally with long robust subapical hook ( Fig. 11 ); parameres robust, elongate and narrowing apically, about twice as long as wide at base, with rounded and setose apices.

Females and immature stages unknown.

Figures

FIGURE 1. Holotype of Drilorhinus klimenkoi gen. et sp. nov. Scale bar = 1 mm.

FIGURES 2–8. Drilorhinus klimenkoi gen. et sp. nov., holotype, details. 2: head, frontal. 3: antenna; 4: maxillary palpus; 5: labial palpus; 6: prosternum; 7: head and prothorax, lateral; 8: scutellum. Scale bars = 1 mm: a, for Figs. 2, 3, 6–8; b, for Figs. 4, 5.

FIGURES 9–11. Drilorhinus klimenkoi gen. et sp. nov., holotype, details. 9, 10: aedeagus dorsal; 11: subapical hook of penis trunk, lateral. Scale bar = 0.5 mm.