Ochthebius zulu, 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 : 17-19

Ochthebius (s.s.) zulu , new species

( Figs. 11 , 12 , 20 )

Type Material. Holotype (male): South Africa: KwaZulu-Natal Province: Nqutu, mountain stream, 28° 12' S, 30° 40' E, 14–30 ix 1950, A. H. Newton (NHM).

Differential Diagnosis. This species, a member of the Namibiensis group, is similar to O. namibiensis in the lack of "accessory series" on the elytra. The dorsal habitus ( Fig. 11 ) is similar to that of O. namibiensis ; differentiated therefrom by the smaller size (ca. 1.71 mm vs. 1.87 mm), the less rounded sides of the elytra, and the less elongate pronotum. An imaginary line connecting the pronotal foveae forms more or less a square in O. zulu , whereas an elongate rectangle in O. namibiensis . The aedeagus of O. zulu ( Fig. 12 ) also clearly indicates a relationship to O. namibiensis ; however, the two distinctively differ in shape of the apex of the main piece and shape and size of the distal piece.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.71/0.77; head 0.38/0.51; pronotum 0.42/0.59, PA 0.52, PB 0.53; elytra 1.07 /0.77.

Color: Black, shining, somewhat aeneous, clothed with distinctive white recumbent or subdecumbent pubescence, maxillary palpi, antennae and legs brunneous, apex of last palpomere and apex of distal tarsomeres darker.

Head: Eyes moderately large, in dorsal aspect 8 convex facets in longest series. Ocelli without relief, location vaguely indicated by absence of setae. Interocular foveae deep, width of each slightly less than distance separating them. Frons with small round basomedian fovea. Frons and clypeus with punctures of setal sockets fine, ca. 1/2xef, rather sparse; interstices shining, 1–5xef, not perceptibly micropunctulate; white recumbent setae about twice as long as average distance between setal sockets. Labrum more densely setiferously punctate that clypeus, anterior margin entire in dorsal aspect, in frontal aspect weakly emarginate in middle 1/3 where margin narrowly upturned.

Mandible with outer surface bearing rather short tapering curving setae. Pronotum: Anterior margin very shallowly bisinuate, without postocular emarginations or processes, with well-developed bisinuate hyaline border. Widest just behind anterior angles, then sides sinuately attenuate to rectangular posterior angles. Lateral hyaline border moderately wide, beginning at about midlength of lateral depression, edge straight or very weakly arcuate, posteriorly continuing very narrowly along base. Disc with narrow midlongitudinal sulcus constricted at middle, anterior and posterior foveae well developed, all depressions microreticulate within; setiferous punctures moderately sparse, about same size and density of those of frons, interstices strongly shining, without evident micropunctulate ground sculpture. Lateral fossula not deep, densely contiguously punctulate. Lateral depression slightly more densely punctate than reliefs. Elytra: Elongate oval, widest about middle, explanate margin very narrow, narrower than tarsal apex. Apices narrowly separately rounded. Ten distinct series of punctures, no "accessory series". Punctures coarser basally, finer apically, on disc punctures ca. 1xef, longitudinally separated by 2–3xpd; each puncture with recumbent whitish seta, length ca 2x distance between punctures; series not striate-impressed except sutural in distal 1/2. Intervals flat, moderately shining, very weakly effacedly alutaceous, width on disc 2– 3xpd. Venter: Mentum weakly shining, effacedly microreticulate, moderately densely and moderately coarsely sparsely setiferously punctate. Metaventrite and abdominal ventrites 1–5 entirely clothed in dense hydrofuge pubescence. Ventrite 6 shining except very narrow band of hydrofuge pubescence at anterior margin, posterior 1/2 with sparse, long setae.

Etymology. Named in reference to the geographical distribution.

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

Figures

FIGURE 11. Ochthebius zulu, dorsal and lateral habitus of holotype.

FIGURE 12. Ochthebius zulu, aedeagus of holotype.

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