Infrantenna, 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 : 46-48

Infrantenna gen. nov.

urn:lsid:zoobank.org:act:5187D839-B85D-48B4-8321-738F3E5CFD6D

Type species

Infrantenna fissilis gen. et sp. nov., here designated.

Diagnosis

A member of the tribe Xyloperthini as characterized by the antennal club segments elongated, the mandibles crossed at the tips, and the lamelliform intercoxal process of the first abdominal ventrite ( Lesne 1901; Fisher 1950; Liu & Schönitzer 2011). This taxon is distinguished from other genera of Xyloperthini by the following combination of characters: frons weakly convex, without tuft of long upwardly directed hairs on the head in either sex. Antennal fossa inserted next to lower intero-lateral margin of eyes below the fronto-clypeal suture; eyes strongly detached from cheek. Posterior part of elytral disc without costae or teeth, infero-lateral margin of elytral declivity strongly raised to form a false epipleuron; female elytra declivity with deep clefts extending a little above the middle of the declivity, dividing the outer part of the declivity from a pair of elongate, raised and grooved sutural lobes; posterior margin of 5 th abdominal ventrite strongly emarginate in female; 5 th abdominal ventrite of male with pleural pieces.

Etymology

The genus name is feminine, and refers to the unusually low position of the antennal fossa.

Description

BODY. Elongate, cylindrical. Head deeply inserted in prothorax, not visible from above.

HEAD. Frons weakly convex, without tuft of long upwardly directed hairs on the head in either sex, apart from a pair next to the inner margin of the eyes; fronto-clypeal suture dark, impressed in middle; clypeus strongly transverse. Mandibles subequal, sharply pointed. Eyes large, globose, strongly detached from cheeks posteriorly. Antennal fossa inserted next to lower intero-lateral margin of eyes below frontoclypeal suture, antenna with ten antennomeres, first and second antennomeres elongate, antennomeres 3–7 forming funicle, each antennomere short, fifth widest, together subequal to first club antennomere in length; antennomeres 8–10 forming elongate, loose club, each antennomere with short, recumbent hairs, two distinct C-shaped sensory impressions near anterior margin of antennomeres 8 and 9, indistinct sensory patches ⅓ of length from apex on last antennomere; antennomeres 8 and 9 subequal in length, last antennomere elongate, oval, longer than penultimate antennomere, but subequal in width.

PRONOTUM. Slightly wider than long, widest at base, antero-lateral angle with small, strongly upcurved tooth on each side, anterior margin between upcurved teeth slightly concave; sides broadly rounded, converging more strongly anteriorly, posterior angles broadly rounded, without lateral carina; anterior slope coarse with 4 large upcurved teeth antero-laterally on each side; discal surface shining, sparsely punctate.

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

ELYTRA. Subequal to pronotum in width, parallel-sided, shining, disc and sides rugulose with small punctures, bearing minute hairs. Elytral declivity sexually dimorphic. Male with declivity concave, puncturation stronger and becoming smaller and shallower towards apex, declivital margins forming distinct infero-lateral epipleuron (false epipleuron of Lesne 1901) gradually narrowing to sutural apex to form carina which runs into the apical margin. Female with declivity convex, with deeper and larger punctures, infero-lateral epipleuron distinct and abruptly cut into semi-circular emargination from middle to apex; elytral declivity with deep clefts extending a little above middle of declivity, dividing outer part of declivity from a pair of elongate, raised and grooved sutural lobes.

ABDOMEN. In female, 5 th abdominal ventrite strongly emarginated in middle on posterior margin. Last visible abdominal ventrite of male with pleural pieces.

LEG. Subequal in length, procoxae separated by narrow intercoxal process of first thoracic ventrite, mesocoxae very narrowly separated; tibiae expanded toward apices, protibiae broadly, shallowly grooved on external face, protarsi longer than the length of protibiae, with series of long hairs beneath, meso- and meta-tarsi longer than their respective tibiae.

Remarks

Infrantenna gen. nov. can be distinguished from all other xyloperthine genera by the combination of the frons with only one long hair on each side next to eyes, the antennal fossa placed very low on the head below fronto-clypeal suture, 10-segmented antennae with two C-shaped sensory areas near anterior margin of 1 st and 2 nd club segments, without lateral carina of pronotum, the female with deep clefts on the elytral declivity and strongly emarginated 5 th abdominal ventrite and male with pleural pieces of 5 th abdominal ventrite.

Five genera which appear to be related to Infrantenna gen. nov. in their form and morphology have been selected, and characters considered to be potentially informative in the determination of phylogenetic relationships are compared in Table 1 . Psicula Lesne, 1941 is the most similar genus morphologically to Infrantenna gen. nov. It has similar modifications of the apex of the elytral declivity and last abdominal ventrite of the female, and has a similar distribution. However, Psicula has nine-segmented antennae and, like all the other genera compared, a more dorsal location of the antennal fossa. The last ventrite of the male also lacks pleural pieces. The African genus Xylion differs in the modifications of the female abdominal ventrites with variously modified from 3 rd to 5 th ventrites. The Australian genus, Xylobosca Lesne, 1901 , differs in the sexually dimorphic frons, the first abdominal ventrite of female enlarged, and the widest of the protibia toward to middle. The North American genus, Xyloblaptus Lesne, 1901 , which is the only selected genus with entire declivital apex in both sexes, lacks male pleural pieces, and has the widest of the protibia toward to middle. The protibia of the Mediterranean genus, Xylopertha Guérin- Méneville, 1845, has the same form as Infrantenna gen. nov., but it differs in the nine-segmented antenna, and the higher position of the antennal insertions.

Based on either geographical distribution or morphological characters, Psicula is the most similar genus to Infrantenna gen. nov.

Distribution

Northern Thailand.