Baiocis spiniventris 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 : 489-490

Baiocis spiniventris Beaver & Liu , new species

( Fig. 9 , 22‒23 )

Male: 2.7‒2.8 mm long, 4.9‒5.1 times as long as wide, light brown, the head and apical half of the elytra darker, the basal half of the elytra paler, vestiture very sparse. Head with frons weakly, broadly impressed above epistoma, and along the midline, rugulose, shining, quite coarsely punctured, the punctures with short erect hairs, median stria short and indistinct, vertex strongly angled with the frons, separated from it by a transverse convex ridge. Eye broadly oval, slightly longer than deep. Pronotum 1.5‒1.6 times longer than wide, widest behind deep femoral grooves, maximum width about 1.4 times minimum, disc smooth, shining, weakly alutaceous close to apical and basal margins, almost glabrous above, a few short hairs laterally, disc with very fine, scattered punctures, median line extending from near base to just anterior to the narrowest part of the pronotum. Elytra 2.6‒2.7 times as long as wide, 1.6‒1.7 times as long as pronotum, horizontal, the sides weakly convex, widest at about middle, lacking a constriction before apex, the lateral margins with 3‒4 serrations close to apex, each serration with a single hair, disc smooth, shining, glabrous except for a row of hairs near lateral margin, and a very few scattered hairs on posterior half, striae finely punctured, not impressed, interstriae indistinct, the punctures of similar size, but more regularly and distantly placed than on striae, disc terminating apically in a carinate rim bearing short hairs, the rim forming a shallow V with weakly convex sides, declivity narrow, lunate, concave, shining, apicolateral angle projecting in a small, acutely pointed, vertically directed tooth, not visible from above. Abdomen with apex of ventrite 1 strongly raised and thickened in median third, its apical margin weakly tuberculate at each end, slightly projecting over ventrite 2 which is humped medially at base, and bears two strong, pointed teeth separated by about the width of the process on ventrite 1, and extending over ventrite 3, ventrites 3‒4 shining, the apical margins slightly thickened, each with a row of erect hairs at the sides, not extending across the median third, ventrite 5 concave, its margins thickened, a single hair on each side near the margin. Anterior margin of impression on metaventrite and metanepisternum with a single, small tooth on metanepisternum. Metacoxa with a spine on its inner margin, projecting posteriorly, its tip slightly curved ventrally.

Female: Unknown.

Holotype: Male : BRUNEI, Temburong, Nr. K. Belalong Field Stud. Centre, 4° 33' N, 115° 09' E, 250m, RGS/ UBD Exped., 10.ii.1992 (R. A. Beaver). (Deposited in BMNH)

Paratypes: Male: 4 specimens: as holotype except: 7.ii.1992 (2), 4.iii.1992 (2) ( BMNH, RAB)

Etymology: The Latin specific name is composed of the genitive form of the noun spinus and the genitive form of the noun venter (ventral side of abdomen), and refers to the spine-like teeth (spina) on the second ventrite of the abdomen (venter).

Diagnosis: Baiocis spiniventris belongs to the group of species, including inimicus (Schedl) , orientalis , sublunaris (Schedl) , sumatranus n. sp. and unispineus Roberts , in which the apex of the elytral disc is smooth and shining, the elytral emargination is crescentic or shallowly V-shaped, and the apical rim is sharply separated from the declivity by a carina, and projects over the declivity. The posterolateral tooth of the elytra is not visible from above. It can be distinguished from these species by the abdominal armature ( Fig. 9 ): the first ventrite lacks a median process and the second is armed by two strong teeth. In B. inimicus and B. sumatranus , the first ventrite bears a truncate median process, but the second ventrite is unarmed. In B. sublunaris , the first ventrite bears a small median triangular spine, but the second ventrite is unarmed. The abdomen is unarmed in the remaining species in the group.

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.