Parhydraena namaqua, Perkins, 2009

Perkins, Philip D., 2009, Revisions of the genera Parhydraena Orchymont, Protozantaena Perkins, Decarthrocerus Orchymont, and Parhydraenopsis nomen novum, aquatic and humicolous beetles from Africa and Madagascar, and comparative morphology of the tribe Parhydraenini (Coleoptera: Hydraenidae), Zootaxa 2038, pp. 1-119 : 28-29

Parhydraena namaqua new species

( Figs. 51, 53, 97)

Type material. Holotype (male): South Africa: Western Cape Province, Van Rhyns Pass [Namaqualand], 31° 23' S, 19° 1' E, 1.xii.1977, V. Whitehead. Deposited in the TMSA.

Differential diagnosis. Similar in dorsal habitus to P. parva and P. ora ( Figs. 42, 51, 54). Distinguished from P. parva by the larger size (length ca. 1.77 vs. 1.64 mm), the comparatively shorter maxillary palpi (palpus length/head width ca. 0.75 mm), and the different shape, in males, of the 6th abdominal ventrite. Males have the 6th ventrite modified similar to that of P. ora . The male genitalia distinctively differ in the three species, and should be examined for reliable determinations ( Figs. 44, 53, 56).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.75/0.80; head 0.28/0.48; pronotum 0.40/0.64, PA 0.50, PB 0.55; elytra 1.07 /0.80. Head and pronotal disc piceous, area surrounding pronotal disc brown; elytra, legs and maxillary palpi dark brown, apex of distal mere of maxillary palpus not darker than remainder of palpus.

Head with eyes moderately large, in dorsal aspect 8 convex, moderately coarse facets in longest series. Ocelli distinct round small shining, each located at base of shallow oblique interocular fovea. Frons on disc distinctly finely punctate, ca. 1xef, interstices microreticulate, dull, 1–3xpd; area between interocular foveae and eye microreticulate, punctate, dull. Clypeus dull, microreticulate very indistinctly, if at all, punctate, except anterior margin shining. Labrum dull, as long as clypeus, apicomedially emarginate to form rounded lobe on each side; laterally fringed with short arcuate setae. Maxillary palpi elongate, combined lengths of meres less than width of head (ratio ca. 24/32); ratios of meres 2–4 ca. 7/5/12. Mentum and submentum sparsely finely punctulate, microreticulate.

Pronotum with anterior margin straight or nearly so, median 1/3 with extremely narrow hyaline border. Anterior angles obtuse, moderately angulate. Sides rounded, widest at middle, behind middle gradually attenuate, very weakly sinuate. Posterior angle obtusangulate. Pronotum coarsely and very densely punctate, rugulose, dull, except discal relief more finely punctate, ca. 1xef, interstices smooth and shining. Discal impressions deep, broadly U-shaped, many punctures confluent; rather deep, wide impression at each posterior angle. Each puncture with anterior margin extended posteriorly as narrow ridge, dividing puncture into a pair of two smaller punctures, most punctures with indistinct, short recumbent or decumbent seta arising from posterior extreme of dividing ridge.

Elytra elongate-ovate, sides weakly arcuate, margins distinct from shoulder for 4/5 of length. Ten-seriate punctate, only first series striate-impressed, in distal 1/2; punctures ca. 1xef, longitudinally separated by ca. 1xpd, becoming finer and shallower on apical declivity, each puncture with minute granule at anterior margin. Interval width ca. 2xpd, shining, each with unilinear row of rather widely spaced, minute granules, each granule at its posterior side with very indistinct, very short recumbent seta, setae very similar in length and density to setae of serial punctures.

Metaventrite with moderately deep median elongate oval impression in basal 1/2, midlongitudinal shining carina between anterior extreme of oval impression and mesoventral intercoxal process. Metaventrite and abdominal ventrites 1–4 hydrofuge pubescent. Ventrite 5, in male, hydrofuge pubescent in basal 1/2 laterally, posterior margin of pubescent area produced in middle to 2/3 length of ventrite, this area weakly concave; in female basal 1/2 of ventrite hydrofuge pubescent; shining part of ventrite 5 very sparsely pubescent in both sexes. Ventrite 6 very weakly, effacedly microreticulate, shining, in male with low transverse ridge over median 1/3; in female shape simple, with transverse band of sparse setae across posterior 1/2. Male: last ventrite asymmetrical, apex lobiform and setose; last tergite with tuft of setae and apicomedian notch into which fits lobe of last ventrite. Female: last ventrite sparsely pubescent, margin rounded; last tergite with small tuft of setae on each side of very weak apicomedian emargination.

Legs moderately long and slender, combined lengths of metatibia and metatarsus greater than width of head (ratio ca. 45/32), ratio of lengths of metatibia/metatarsus ca. 25/20. Basal 3 pro- and mesotarsomeres, in male, with pad of suction setae.

Aedeagus length ca. 0.42 mm; main-piece, in left lateral view, with large pointed process; distal process, in left lateral view, with large pointed process and large hood-like process, latter with bifurcate left margin ( Fig. 53).

Etymology. Named in reference to the geographic distribution.

Distribution. Currently known only from the type locality, Van Rhyns Pass near Namaqua, Western Cape Province ( Fig. 97).