Onicotis Murray, 1864

Kirejtshuk, Alexander G. & Kovalev, Alexey V., 2022, Monograph on the Cillaeinae (Coleoptera: Nitidulidae) from the Australian Region with comments on the taxonomy of the subfamily, Zootaxa 5103 (1), pp. 1-133 : 111-113

45. Genus Onicotis Murray, 1864

Brachypeplus (Onicotis) Murray, 1864: 288 ;

Type species: Brachypeplus (Onicotis) auritus Murray, 1864 ;

Onicotis: Kirejtshuk 2008: 120 .

Diagnosis. This genus is characterized by the subelleptic oval body, evenly convex dorsally and concave ventrally; head and pronotum sparsely and very finely punctured, and also with very sparse and very coarse punctures, each elytron with seven deep striae with one row of rather coarse and dense punctures, elytral sides confusely punctured, last three abdominal tergites extremely finely punctured and with sparse and sharp microtubercles; pronotal and elytral sides only subexplanate (not explanate), and also with dense and rather long yellowish golden cilia; dorsum without trace of pubescence; underside with moderately sparse and moderately long, slightly conspicuous yellowish hairs; head with rather large eyes located at base and subacuted laterally, distinct above convergent grooves along eye edge, distinct “neck”; labrum transverse and divided by median suture; scape with long anteroapical process (markedly longer than scape); distinctly outlined antennal grooves forked with mesal branches rectilinearly convergent and lateral ones divergent; pronotum with trapezium-likely excised anterior edge and shallowly bi-emarginate posterior one, anterior angles strongly and posterior ones moderately projecting; elytra very short (combined width about 1.5 × as great as longth); abdominal laterosternites V and VI emarginate along inner side at base and only slightly widened posteriorly (base of laterosternites wider than apex); strongly roof-liked prosternal process; comparatively narrowly comparable separated all pairs of coxae; procoxae clearly closed; posterior edge of metaventrite between coxae arcuately emarginate; tibiae subtriangular and moderately wide; all tarsi very widely lobed; tarsal claws simple and long; posterior edge of male anal sclerite and female pygidium without serration.

Comparison. Onicotis is easily diagnosed after the above key to genera and subgenera and very distinct from all genera of the subfamily in many unique characters, including the regularly subelliptic body with evenly convex dorsum and concave underside, distinct grooves on above surface of head, lateraly subacute eyes located at base of head, forked antennal grooves on underside with rectilinerly convergent and divergent branches, peculiar shape of acape with with long anteroapical process (markedly longer than scape), strongly roof-liked prosternal process, comparatively long pronotal and elytral lateral cilia, very wide tarsi and other characters.

Description. Body comparatively medium-sized (4.9–6.9 mm), subelleptic oval, evenly convex dorsally and somewhat concave ventrally. Dorsal integument smooth and shining, very finely and rather sparsely punctured, and also with very sparse and very coarse punctures, each elytron with six deep striae very clear and deep, seventh stria somewhat obliterated, eighth and ninth striae only traced, externally from striae punctation and sculpture becoming diffused and obliterated, last three abdominal tergites very finely punctured and with sparse and sharp microtubercles; underside finely and very sparsely punctured; dorsum without trace of pubescence, pronotal and elytral sides with dense and rather long yellowish golden cilia; underside with moderately sparse and moderately long and fine, slightly conspicuous yellowish hairs.

Head subflattened, narrowed at base, eyes located behind midlength, slightly convex medially and slightly depressed between median convexity and eye, with anterior edge of frons subtruncate to shallowly emarginate; eyes rather large and located at base and subacute laterally; distinct above convergent grooves along eye edge reaching level of posterior eye end; underside antennal grooves distinctly outlined, with rectilinearly convergent mesal branch divergent and following eye marging lateral ones; mentum comparatively long, rectilinearly widened anteriorly and with slightly projecting anterior angles; pregenal process at hypostomal sinus moderately wide and nearly straight. Ultimate labial palpomere subcylindrical and longer than thick; ultimate maxillary palpomere subcylindrical and comparatively short. 11-segmented antennae bearing compact 3-segmented club without any evident trace of sexual dimorphism; scape with long anteroapical process (markedly longer than scape).

Pronotum widest at base and arcuately narrowing anteriorly, gently and evenly convex, sides only subexplanate (not explanate); anterior and posterior edges bordered, pronotum with trapezium-likely excised anterior edge and shallowly bi-emarginate posterior one, anterior angles strongly and with narrowly rounded tip, posterior ones moderately projecting and with narrowly rounded tip. Scutellar shield subsemicircular. Elytra somewhat arcuate at sides and widely rounded to subtruncate at apices remaining last three abdominal segments completely and one previous one partly uncovered, very widely subexplanate at narrowly bordered sides, very short (combined width about 1.5 × as great as length). Abdominal laterosternites V and VI emarginate along inner side at base and only slightly widened posteriorly (base of lateroventrites wider than apex). Pygidium strongly transverse, slightly medially convex and concave at sides and widely rounded at apex. Prosternal process strongly roof-like, not curved along procoxae and strongly widened at widely rounded and subtruncate apex. Procoxae clearly closed posteriorly. All pairs of coxae narrowly separated. Mesoventrite medially somewhat convex, at sides with distinct depressions for receipt of mesofemora. Metaventrite with distinct median suture, posterior edge of metaventrite between coxae angularly excised. Hypopygidium transverse and widely emarginate at apex in male and subtruncate at apex in female.

Legs comparatively short and moderately wide. Tibiae moderately wide and subtriangular, rounded at outer apical angle; two borders along meso-and metatibiae bearing dense and short setae; spurs rather short and stout. Tarsi with very widely lobed tarsomeres 1–3 and claws simple.

Male anal sclerite moderately long and with widely rounded apex. Aedeagus heavily sclerotized, moderately short, with subacute apex of penis trunk and tegmen almost rectilinearly narrowing to apex. Ovipositor of usual generalized structure, inner and outer lobes gonocoxites well isolated, inner lobes behind outer lobes heavily sclerotized, moderately long styli located subapically.

Composition. Only one species is known.

Notes on bionomy. The type species seems to be a specialized inhabitant of bee nests.

Distribution. Only Australia.