Infrantenna fissilis, Liu & Sittichaya, 2022

Liu, Lan-Yu & Sittichaya, Wisut, 2022, The Oriental genera of Xyloperthini (Coleoptera: Bostrichidae: Bostrichinae), with a new genus and species from Thailand, and a key to the genera, European Journal of Taxonomy 828, pp. 45-60 : 48-52

Infrantenna fissilis gen. et sp. nov.

urn:lsid:zoobank.org:act:4BEB3BB9-D678-4C4A-B25C-334872F069B9

Figs 1–4

Etymology

The name ‘ fissilis ’ is from the Latin word for ‘cleft’ which refers to the deep clefts of the elytral declivity of the female.

Type material

Holotype THAILAND • ♂; Mueang District , Maehongson Province; 19°08.01′ N, 98°12.30′ E; 7 Mar. 2019; ex. semi-dry twig of unknown Fagaceae L.; col. W. Sittichaya; NHMUK014433955 .

Allotype THAILAND • ♀; same collection data as for holotype; NHMUK014433956 .

Paratype Thailand • 1 ♀; same collection data as for holotype; PMCSNHM .

Description

Male ( Figs 1–2 )

MEASUREMENTS. 3.3–3.6 mm long, about 2.6–3.0× as long as wide.

COLORATION. Head, pronotum, pro- and mesotibiae and tarsi, ventral side reddish brown, labrum, antennae, elytral disc, pro- and mesofemora and whole hind legs brown, pronotum and elytra gradually becoming darker brown anteriorly and posteriorly respectively, elytral declivity dark brown.

HEAD. Mandibles dark, stout, apex strongly pointed, inner margin sharp. Labrum trapezoid, narrowed towards base, fringe of dense, short, golden hairs along anterior margin, and fringe of long, yellowish hairs along anterior and lateral margins ( Fig. 1A ). Clypeus transverse, finely punctured, anterior margin emarginated in middle to cover base of labrum and pair of small, broadly rounded teeth on either side. Fronto-clypeal suture dark, attenuated laterally, with median fovea ( Fig. 1A ). Frons rugulose with sparse, fine punctures, each puncture with short, white hair; one long upwardly-directed hair close to intero-lateral margin of eye, triangular shining area on lower middle part, and triangular area with reticulations on upper part above shining area ( Fig. 1A ), upper part with row of small punctures between each two rugosities. Vertex with sparse small punctures, longitudinal rugosities slightly angled toward midline arranged along whole vertex ( Fig. 1A ). Eyes large, strongly detached from cheeks posteriorly ( Fig. 1A ). Antennal fossa inserted next to lower intero-lateral margin of eyes below fronto-clypeal suture ( Fig. 1B ). Antennae 10-segmented, 1 st and 2 nd antennomeres subequal in length, 3–7 antennomeres together subequal to first club antennomere and shorter than last club antennomere in length, first and second club antennomeres subtriangular and subquadrate, wider than long, with small, visible C-shaped areas of dense sensillae close to middle part of anterior margin, last club antennomere more elongate, and longer than penultimate antennomeres, sensory areas indistinct patches at one-third of length from apex ( Fig. 1C ).

PRONOTUM. 1.1–1.2× as wide as long, widest at base, antero-lateral angles with small, strongly upcurved tooth, semicircular area above anterior margin with transverse rugosities; sides of pronotum broadly rounded, converging more strongly anteriorly, posterior angles broadly rounded ( Fig. 2A ), without lateral carina ( Fig. 2B ), postero-lateral area with fine rugosities ( Fig. 2C ); anterior slope coarse with 4 large upcurved teeth antero-laterally on each side, 2–3 teeth next to antero-lateral upcurved teeth small, remaining teeth gradually reduced in size towards summit, and arranged approximately in arcs ( Fig. 2A–C ); discal surface shining with sparse punctures, sparser toward posterior angles, posterolateral areas with small, slightly elongate rugulosities and series of granuloistes along posterior angles ( Fig. 2B–C ). Anterior slope with short, semi-erect hairs between teeth, recumbent hairs on sides.

SCUTELLUM. Small, tongue-shaped, with very sparse punctuation.

ELYTRA. 1.8–2 × as long as wide, parallel-sided, shining, disc and sides rugulose with small punctures, bearing minute hairs; epipleuron narrow, elongated triangular; declivity concave, puncturation larger than on disc, but becoming smaller and shallower toward apex with triangular, nearly glabrous area at apex, sutural margin raised, more strongly in apical three-quarters of declivity ( Fig. 2D ), declivital margins forming distinct rim at sides and apex, infero-lateral epipleuron distinct gradually narrowing to sutural apex to form carina which runs into apical margin ( Fig. 2C, E ); margin slightly upwardly raised at sutural apex and with tiny V-shaped emargination at apex of declivity ( Fig. 2D ).

LEGS. Protibiae expanded from base to apex, broadly, shallowly grooved on external face ( Fig. 2A–B ). Protarsi with long hairs underneath. Second and third segments of tarsi subequal in length and shorter than last segment.

ABDOMEN. Abdominal ventrites finely, moderately densely punctured, punctures with moderately long, whitish hairs; last ventrite with pleural pieces, posterior margin slightly concave with fringe of dense, short, yellowish hairs and fringe of very long, golden hairs along posterior margin ( Fig. 2C ).

Female ( Figs 3–4 )

MEASUREMENTS. 4–4.5 mm long, about 3× as long as wide. Generally similar to male, but pronotum 1–1.1 × as wide as long and elytra 2–2.2× as long as wide.

ELYTRA. Discal punctures become larger posteriorly, declivity convex, with deeper and larger punctures ( Fig. 3A, D ), piceous and darker on raised sutural margin and latero-apical margin ( Fig. 3A, C–D ); infero-lateral epipleuron distinct and abruptly cut into semi-circular emargination from middle to apex with only posterior margin continuing to apex ( Fig. 3B–C ); elytra with two narrow fissure-like emarginations extending from close to apex about two-thirds of height of declivity, separating a narrow inner, leglike, grooved process from the outer part of declivity ( Fig. 3D ), each process minutely and sparsely punctured, with sinuate lateral margin, constricted before apex and then slightly raised to form spoon-like apex; inner margin of outer part of declivity thickened, inner area abruptly, strongly raised, gradually sloping downward towards apex, forming an arc ( Fig. 3A, C–D ).

ABDOMEN. Last abdominal ventrite strongly curved upwards at sides to form triangular profile ( Fig. 4B ), ventrally with deep, broad emargination in one-third of middle part forming trapezoidal arc with pair of strongly sclerotised protrusions on sides, margin of trapezoidal arc and protrusion sclerotised, thickened ( Fig. 4A–C ), and sinuate with a pair of tubercles in middle, and pointed, slightly upwardly curved hook on inner side of protrusion, and postero-dorsal upwardly curved hook on postero-lateral angle on both sides ( Fig. 4A, C ), fringe of long, golden hairs along inner margin of trapezoidal arc and external side of sclerotised, thickened margin of protrusion ( Fig. 4A–C ). Abdominal 5 th tergite convex with transverse prominence in middle third, two oval pads of very dense, short, white hairs on apical half behind prominence ventrally ( Fig. 4A, C ).

Biology

As a member of the family Bostrichidae , the species is likely to be polyphagous. The junior author extracted the specimens from a semi-dry twig of an unknown species of Fagaceae L. We suggest that the hind legs could move vertically in the clefts to clean wood frass. The strongly developed last abdominal ventrite and tergite of the female may help to hold the male genitalia during mating and support the ovipositor during oviposition. Observations of mating and oviposition behaviours are necessary to confirm this hypothesis.

Distribution

Northern Thailand.

Figures

Fig. 1. Head of Infrantenna fissilis gen. et sp. nov., ♂, holotype (NHMUK014433955). A. Frontal view. B. Fronto-lateral view. C. Antennae. Not to scale.

Fig. 2. Infrantenna fissilis gen. et sp. nov., ♂, holotype (NHMUK014433955). A. Dorsal view.B. Lateral view. C. Ventral view. D. Declivity. E. False epipleuron. Scale bar = 1 mm.

Fig. 3. Infrantenna fissilis gen. et sp. nov., ♀, allotype (NHMUK014433956). A. Dorsal view. B. Ventral view. C. Lateral view. D. Declivity. Scale bar = 1 mm.

Fig. 4. Apical posterior of female of Infrantenna gen. nov. and Psicula Lesne 1941. A–C. Infrantenna fissilis gen. et sp. nov., allotype (NHMUK014433956). A. 2nd to 5th visible abdominal ventrites and apical part of last tergite with two very dense, short hairy oval pads on apex. B. Ventral view of last two ventrites. C. Apical-lateral view of last ventrite and declivity. D. Psicula heterogama Lesne 1941, ventral view of last two visible abdominal ventrites.