Ochthebius anchorus, 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 : 10-11

Ochthebius (s.s.) anchorus , new species

( Figs. 5 , 6, 20 )

Type Material. Holotype (male): South Africa: KwaZulu-Natal Province: Oribi Gorge, general collecting, 30° 43' S, 30° 16' E, 28 xi 1989, Endrödy & Klimaszewski (2726) ( TMSA). Paratypes (47): Namibia: Fish River Canyon near View point, 27° 37' S, 17° 36' E, 20 xi 1993, K. Ebert, W. Mey, F. Koch (47 ZMHB).

Differential Diagnosis. The dorsal habitus of this species ( Fig. 5 ) is quite similar to that of O. spinasus , but differs in having deeper pronotal foveae that have more abrupt margins. O. anchorus is less convex dorsally, and has elytra with less rounded sides and less acuminate apices. The aedeagi of the two species differ distinctively in shapes of both the main piece and the distal piece, and should be examined for reliable determinations ( Fig. 6).

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.74/0.76; head 0.31/0.42; pronotum 0.39/0.55, PA 0.48, PB 0.48; elytra 1.03/0.76. Color: Head black, weakly aeneous; pronotum brown to dark brown; elytra brown to light brown, columellae of serial punctures dark brownish; antennae, maxillary palpi and legs, except coxae, bright stramineous, contrasting sharply with dark brown Venter: Head: Eyes rather small, in dorsal aspect 7–8 weakly convex facets in longest series. Frons weakly shining, distinctly but finely sparsely setiferously punctate, punctures ca. 0.5xef or smaller, setae recumbent, setal length and interstices both 1–3xef but denser near eyes; interocular foveae large, round, deep, width of each about equal distance separating them, each internally with few setiferous punctures. Clypeus weakly shining, sculpture very similar to frons, sides densely pubescent. Labrum shining, very finely setiferously punctate; anterior margin apicomedially upturned to form small tooth, area behind tooth weakly concave. Pronotum: Subcordate, widest just behind anterior angles; anterior margin very weakly bisinuate, without postocular emarginations, with very small postocular processes, hyaline border well developed; sides sinuately attenuate to posterior angles; rather wide lateral hyaline border beginning just behind anterior angles, edge weakly arcuate or straight over median 0.8, continuing around basal angles and along base. Disc with anterior and posterior impressions each consisting of three confluent, rugulose foveae; anterior impression deep, somewhat T-shaped, midlongitudinal extension nearly attaining posterior impression, outer edge of impression abrupt; posterior transverse impression larger and deeper, lateral foveae longer than wide, 2–3 times size of oval median fovea, outer edges of impression abrupt; reliefs shining, moderately coarsely and moderately densely punctate but spacing of punctures quite irregular, interstices 1–xpd, size 1–3xef, smaller in middle of disc, interstices apparently lacking 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 in male, about equal to greatest width of tarsus, slightly wider in female. Apices narrowly conjointly rounded in both sexes. Ten-seriate punctate, series not at all striate-impressed except sutural series behind middle, on disc punctures well impressed, larger than largest pronotal punctures, ca. 3–4 xef, without granule at anterior margin, interstices ca. 0.5–1xpd, distally punctures progressively smaller and more longitudinally separated. Intervals flat, very weakly shining, ca. 1–1.5xpd. Serial setae fine decumbent and short, each attaining base of next seta in series; nervure setae indistinct. Venter: Mentum shining, moderately sparsely setiferously punctate. Metaventrite pubescent laterally, disc with large, subtriangular, 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 pronotal discal impressions that, taken together, resemble an anchor. Distribution. Currently known from only two, very disjunct localities ( Fig. 20 ). The eastern locality is represented by only one male, the holotype.

Figures

FIGURE 5. Ochthebius anchorus, 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.