Baiocis crassiventris Beaver & Liu, 2018

Beaver, Roger A., 2018, A review of the genus Baiocis Browne, 1962 (Coleoptera: Curculionidae: Platypodinae), with new species, new synonymy and a key to males, Zootaxa 4434 (3), pp. 481-501 : 483-484

Baiocis crassiventris Beaver & Liu , new species

( Figs. 1‒3 , 18‒19 )

Male: 2.4 mm long, about 5.2 times as long as wide, yellowish-brown, the head and elytral apices darker reddishbrown, the bases of the elytra paler, vestiture very sparse.

Head viewed from side a little longer than high, eye large, egg-shaped, about 1.3 times longer than high, its shorter axis at the posterior third ( Fig. 2 ), frons with a very short, broadly, shallowly impressed, vertical section above the epistoma, this curving into a longer weakly sloping section which runs into the vertex without a transverse ridge or carina, a transverse row of longer, erect, backwardly curving hairs marking the junction between frons and vertex, the surface alutaceous, finely, moderately densely punctate, the punctures with short erect hairs, median stria short. Pronotum 1.85 times longer than wide, widest behind deep femoral grooves, maximum width about 1.6 times minimum, disc smooth, shining, weakly alutaceous near base and apex, with scattered, very fine punctures, median line extending from near base to just anterior to the narrowest part of the pronotum. Elytra 2.6 times longer than wide, 1.6 times longer than pronotum, horizontal, vase-shaped, widest a little before middle, then constricted to shortly before apex, where slightly expanded into downcurved, posterolateral processes; elytral disc shining, striae not impressed, very finely, sparsely punctured, interstriae indistinct, the sides weakly serrate before the apex, posterior rim of disc narrowly, triangularly emarginate medially, extending over the declivity, its margin sharply carinate from suture to posterolateral processes, declivity narrow, lunate, strongly concave, concealed below projecting discal rim, posterolateral processes long, acutely pointed, the tips making an angle of 30‒40°. Abdomen with ventrites 2‒4 shining, their apical margins raised and thickened, projecting over the next posterior ventrite at the sides of the ridge as rounded lobes, a row of long hairs anterior to the apical margin of each ventrite and extending across it, ventrite 5 strongly concave with a single long hair on each side near the lateral margin, otherwise glabrous. Anterior margin of impression on metanepisternum and metaventrite with a short costa on metanepisternum. Metacoxa with a small backwardly directed spine on posterior inner margin.

Female: 2.35 mm long, about 5.2 times as long as wide, generally resembling male but a little paler and more weakly sclerotised, frons plano-concave, more steeply sloping, rounded into vertex, frontal impression extending almost onto vertex, with a denser vestiture of upwardly-directed, short hairs, median stria longer and stronger. Antennal club clearly larger than in male. Pronotum about 1.7 times longer than wide, the difference from the male caused by the flattening of the weakly sclerotised structure, otherwise very similar. Elytra 2.7 times as long as wide, 1.8 times as long as pronotum, almost parallel-sided without a strong constriction before the apex, the declivity short, weakly concave, without a carina above, with a fairly dense covering of very short, erect hairs, the posterolateral processes very short, bluntly rounded. Abdominal ventrites not thickened or projecting apically, fifth ventrite convex. Metanepisternum without a costa. Metacoxa with a small tubercle on posterior inner margin.

Holotype: Male. Malaysia, Sabah, Sipitang, Mendolong , 29.iv.1988 (S.Adebratt). (Deposited in ZMLU)

Allotype: Female. As holotype, except 11.v.1988. (Deposited in ZMLU)

Etymology: the Latin specific name is a masculine genitive form of the adjective crassus, meaning thick or plump, referring to the thickening of some ventrites of the abdomen (ventris, the genitive form of the Latin noun venter).

Diagnosis: The form of the male head with its short vertical frons, and long, obliquely sloping upper part is unlike any other member of the tribe Platypodini known to us, although a superficially similar head is found in the genus, Notoplatypus Lea (Tesserocerini) . However, the elongate egg-shaped eye and vase-shaped elytra clearly relate the species to Baiocis anaticeps (Schedl) . The male of B. crassiventris can be distinguished from the latter species by the absence of a transverse carina separating the frons from the vertex, the posterolateral process of the elytra is directed somewhat posteriorly rather than vertically, and the posterior margins of ventrites 2‒4 are raised and thickened to form transverse ridges, projecting as rounded lobes over the next posterior ventrite at the sides of the ridge. In B. anaticeps , the posterior margin of the second ventrite only is slightly thickened. The females of this species and B. anaticeps can be distinguished from other species of Baiocis by the oval or egg-shaped eye. In female B. crassiventris , the head is longer than high, not deeper than long, and the elytra are 1.8 times as long as the pronotum, rather than 2.0‒2.1 times as in B. anaticeps .

Biology: Unknown.

Figures

FIGURES 1–9. Baiocis species males. 1‒3. B. crassiventris. 1, dorsal view; 2, lateral view head; 3, lateral view elytral apex. 4. B. anaticeps, lateral view elytral apex. 5‒6. B. perinimicus, elytral apex. 5, posterolateral view; 6, lateral view. 7‒8. B. incisus. 7, dorsal view elytral apex; 8, ventral view abdomen. 9. B. spiniventris, ventral view abdomen. Scale line = 1.0 mm (Fig. 1); 0.5 mm (Figs 2‒6, 9); 0.67 mm (Figs 7‒8).

FIGURES 18–25. Baiocis species. 18‒19. B.crassiventris. 18, male, lateral view (2.4 mm); 19, female, dorsal view (2.3 mm); 20‒21. B. spicatus male (2.5 mm): 20, lateral view; 21, dorsal view; 22‒23. B. spiniventris male (2.7 mm): 22, lateral view; 23, dorsal view; 24‒25. B. angustipennis female (2.5 mm): 24, lateral view; 25, dorsal view.