Ochthebius bicomicus, Perkins, Philip D., 2011

Perkins, Philip D., 2011, New species and new collection records of aquatic beetles in the genus Ochthebius Leach from southern Africa (Coleoptera: Hydraenidae), Zootaxa 3093, pp. 1-34 : 15-16

Ochthebius (s.s.) bicomicus , new species

( Figs. 9 , 10, 20 )

Type Material. Holotype (male): South Africa: Western Cape Province: 22 mi. N. Nelspoort, 31° 51' S, 22° 57' E, 3 iii 1968, P. J. Spangler ( USNM). Paratypes: Same data as holotype (12 USNM).

Differential Diagnosis. This species is quite similar in dorsal habitus to O. sitiensis ; both have very coarsely and confluently punctate pronotal foveae ( Figs. 3 , 9 ). Reliable determinations will be based on examination of the aedeagi, which distinctively differ in shapes of the main piece and the distal piece ( Figs. 4, 10).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.67/0.72; head 0.30/0.44; pronotum 0.39/0.60, PA 0.53, PB 0.50; elytra 1.04/0.72. Color: Head black, weakly aeneous; pronotum brown to dark brown except lighter brown narrowly along base, sometimes with faint metallic reflections; elytra brown, serial punctures dark brownish; antennae, maxillary palpi and legs, except coxae, light brown, venter dark brown. Head: Eyes rather small, in dorsal aspect 7–8 weakly convex facets in longest series. Frons shining, distinctly but finely sparsely setiferously punctate, punctures 0.3xef or smaller, setae recumbent, setal length and interstices both 2–3xef but denser near eyes; interocular foveae large, round, deep, width of each about 2/3 distance separating them, each internally with few setiferous punctures. Clypeus sculpture as frons except punctures slightly denser and sides densely pubescent. Labrum shining, moderately densely setiferously punctate; anterior margin very narrowly upturned from side to side, with minute apicomedian tooth. Pronotum: Subcordate, widest at about anterior 1/4; anterior margin very weakly bisinuate, without postocular emarginations or processes, hyaline border well developed; sides sinuately attenuate to posterior angles; rather wide lateral hyaline border beginning just behind anterior angles, edge weakly arcuate nearly straight over median 0.7, continuing around basal angles and along base. Disc with anterior and posterior transverse impressions rather deep, outer edges of impressions gradually sloping, both impressions deepest in midline, anterior impression somewhat T-shaped, with median subsulcus almost attaining posterior impression; impressions densely coarsely punctate; reliefs shining, coarsely moderately densely punctate but size and spacing of punctures quite irregular, size 1–3xef, smaller in middle of disc, interstices with exceedingly fine and sparse micropunctulate ground sculpture. Lateral depressions subrugosely strongly punctate, slope continuing transverse curvature of disc but appearing slightly inflated. Setae of discal punctures recumbent, fine and indistinct. Elytra: Widest at middle, sides arcuate, explanate margin narrow, about equal to greatest width of tarsus. Apices in both sexes rather narrowly conjointly rounded. Ten-seriate punctate, series not at all striate-impressed except sutural series behind middle, on disc punctures slightly elongate, small but well impressed, about equal size of largest pronotal punctures, ca. 2xef, interstices ca. 0.5–1xpd, punctures without distinct granules at anterior margin, distally punctures progressively smaller and more longitudinally separated. Intervals flat or very weakly rounded, weakly shining, ca. 2xpd. Serial setae decumbent, fine and short but distinct, each attaining base of next seta in series; nervure setae indistinct. Venter: Mentum shining, moderately sparsely setiferously punctate. Metaventrite pubescent laterally, disc with moderately large, subrhomboidal, strongly shining area, glabrous except few setiferous punctures anteriorly. Abdominal ventrites 1–5 entirely clothed with dense hydrofuge pubescence; 6 effacedly microreticulate, weakly shining, sparsely pubescent in distal 1/2.

Etymology. Named in reference to the two smile-shaped impressions of the pronotal disc.

Distribution. Currently known only from the type locality ( Fig. 20 ).

Figures

FIGURE 3. Ochthebius sitiensis, dorsal and lateral habitus of holotype.

FIGURE 9. Ochthebius bicomicus, dorsal and lateral habitus of holotype.

FIGURES 19 – 20. Geographical distributions of Ochthebius. 19. O. endroedyi. 20. O. anchorus, O. bicomicus, O. granulinus, O. involatus, and O. zulu.