Acontosceles borneensis, Yoshitomi, 2019

Yoshitomi, Hiroyuki, 2019, Review of the Asian Thaumastodinae (Coleoptera, Byrrhoidea, Limnichidae), with a phylogeny of the genera, European Journal of Taxonomy 583, pp. 1-45 : 8-9

Acontosceles borneensis sp. nov.

urn:lsid:zoobank.org:act:2582F411-8790-4937-B6A0-248899FD9208

Figs 5A , 6

Etymology

This species is named after its type locality.

Material examined

Holotype MALAYSIA • ♂; “SARAWAK: Nanga Pelagus 7-14. VIII. ‘58”; “ T. C. Maa Collector BISHOP”; BPBM.

Paratypes MALAYSIA • 1 ♂, 2 ♀♀; same collection data as for holotype; BPBM • 1 ♀; same collection data as for preceding; EUMJ • 2 ♀♀; “BORNEO: SARAWAK Merirai Valley nr Kapit, 30-300m, 1-6. VII. 58 ”; “ T. C. Maa Collector BISHOP Mus.”; BPBM • 1 ♀; “BORNEO: SARAWAK Bau , Lake Area 29-30. VIII. 1958 ”; “ T. C. Maa Collector BISHOP”; BPBM .

Description

Male

BODY. Oblong, subparallel-sided, slightly convex dorsally, weakly shiny, closely covered with suberect silver setae. Coloration of body blackish brown, but mouthparts and legs yellowish brown; elytra with obscure silver spots consisting of erect setae.

HEAD. Moderate in size; frons and clypeus closely covered with erect, long silver setae; clypeus with straight anterior margin. Eyes large, prominent dorso-laterally.

ANTENNAE. Reaching about proximal half of pronotum.

PRONOTUM. Widest at basal third, densely bearing short yellowish setae and minute scale-like setae; PW/ PL 2.25–2.50 (2.34). Scutellum small, subtriangular.

ELYTRA. Oblong, subparallel-sided near base to apical fifth, densely covered with short yellowish setae and minute scale-like setae, projecting ventrally in apical part; EL/ EW 1.59–1.80 (1.72); EL/ PL 4.17– 4.63 (4.39); EW/ PW 1.02–1.16 (1.10); TL/ EW 1.97–2.22 (2.11).

ABDOMEN. Sternite VII ( Fig. 6A ) broad, gently arcuate along caudal margin, shallowly concave in median part, bearing about 20 long setae and three pairs of long and stout setae. Sternite VIII ( Fig. 6B ) membranous, bearing minute spines in apical parts. Sternite IX ( Fig. 6C ) moderately sclerotized, large, with small apical plates.

AEDEAGUS ( Fig. 6 D–E). Long, well sclerotized, strongly curved ventrally; basal piece oblong, expanded basally, evenly curved ventrally; lateral lobes long and slender, serrate on dorso-lateral margins, curved ventrally; median lobe long and slender, about 0.6 times as long as lateral lobe, gently curved ventrally; ML/BL 0.36; ML/ LL 0.68.

Female

Sexual dimorphism distinct in the following characteristics: 1) frons and clypeus covered with short yellowish setae; 2) apical part of elytra projecting ventro-apically; 3) sternite VII ( Fig. 6F ) rather pointed on caudal margin, bearing about 40 long setae. Urosternite ( Fig. 6G ) well sclerotized, with long and slender apodeme; lateral projections stout, bifid in apical parts. Ovipositor ( Fig. 6H ) well sclerotized; coxite sparsely punctuate, pointed at apices; approximate ratio of coxite and baculus (n = 1) of 1.0:1.7.

Measurements

Unsexed (n = 4): TL 2.17–2.25 (2.21) mm; PW 0.90–1.00 (0.96) mm; PL 0.40–0.42 (0.41) mm; EL 1.75–1.85 (1.80) mm; EW 1.00–1.10 (1.05) mm.

Distribution

Malaysia ( Sarawak).

Remarks

This species belongs to the hydroporoides species group judging from characteristics of the male genitalia.

Figures

Fig. 5. Acontosceles spp. A. A. borneensis sp. nov., holotype (BPBM). B. A. yorioi Satô, 1966 (EUMJ). C. A. hydroporoides Champion, 1924 (NME). D. A. chujoi Yoshitomi & Satô, 2005 (EUMJ). E. A. siwalikensis Pütz, 2008 (NME). F. A. zetteli Pütz, 2008 (BPBM). Scale bars: 1.0 mm.

Fig. 6. Acontosceles borneensis sp. nov., male (A–E) and female (F–H) genitalia (holotype and paratype, BPBM). A, F. Sternite VII. B. Sternite VIII. C. Sternite IX. D. Aedeagus, left lateral view. E. Aedeagus, ventral view. G. Urosternite. H. Ovipositor.