Parhydraena parva, 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 : 20-21

Parhydraena parva new species

( Figs. 42, 44, 97)

Type material. Holotype (male): South Africa: Western Cape Province, George, Saasveld, Kaaimans River , 33° 57' S, 22° 30' E, 23.iv.1978, W. Breytenbach (WB:1). Deposited in the TMSA . Paratypes (18): South Africa: Western Cape Province, Same data as holotype (12 TMSA) ; Grootvadersbosch N. R., Bushbuck Trail (near Grootvadersbosch R.), berl., wet debris, forest stream, young afromontane forest; FMHD #2004-006, elev. 300–400 m, 33° 59' S, 20° 48' E, 25.i.2004, Newton & Solodovnikov (1075) (1 FMNH) ; Milnerton , 10 mi. N of Capetown, 33° 53' S, 18° 29' E, 18–20.xi.1949, B. Malkin (1 BMNH) ; S. W. Cape, Nuweberg , 10 km NE, shore washing, 34° 34' S, 19° 6' E, 13.xi.1973, Endrödy-Younga (#240) (1 TMSA) ; Small vlei near Cape Town , 33° 55' S, 18° 25' E, 18.xi.1947, J. Omer-Cooper (3 BMNH) .

Differential diagnosis. Similar in dorsal habitus to P. namaqua and P. ora ( Figs. 42, 51, 54); differing therefrom by the smaller size (length ca. 1.64 vs. 1.75 mm) and the comparatively longer maxillary palpi (palpus length/head width ca. 0.90). Males have the 6th ventrite modified similar to that of P. namaqua . 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) 1.64/0.67; head 0.26/0.44; pronotum 0.38/0.57, PA 0.46, PB 0.50; elytra 0.99/0.67. Color brown to dark brown, head and disc of pronotum darkest; maxillary palpi light brown, apex of distal mere of not darker than remainder of palpus.

Head with eyes comparatively small, in dorsal aspect 7 rather coarse, convex facets in longest series. Ocelli distinct round small shining, each located at base of moderately deep oblique interocular fovea. Frons effacedly microreticulate, dull or weakly shining, disc moderately coarsely, moderately densely punctate, punctures slightly larger than 1xef, interstices 1–3xpd; area between interocular foveae and eye flat or very weakly convex. Clypeus markedly microreticulate, dull, except anterior margin shining. Labrum dull, apicomedially emarginate to form rounded lobe on each side; laterally fringed with short arcuate setae. Maxillary palpi elongate, combined lengths of meres slightly less than width of head (ratio ca. 28/31); ratios of meres 2–4 ca. 10/5/13. Mentum and submentum densely finely punctulate, microreticulate.

Pronotum with anterior margin weakly arcuate, median 1/2 with extremely narrow hyaline border. Anterior angles obtuse, moderately angulate. Sides rounded, widest just before middle, behind middle gradually attenuate, straight. Posterior angle obtusangulate. Pronotum coarsely and very densely punctate, rugulose, moderately dull, except discal relief much more finely punctate, punctures shallow and U-shaped, ca. 1xef, interstices smooth and shining. Discal impressions moderately deep, broadly U-shaped, many punctures confluent. Shallow, 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. 2–3xpd, shining but with irregular reflections, each with unilinear or slightly irregular row of minute granules, each granule at its posterior side with short recumbent seta, setae very similar in length and density to setae of serial punctures.

Metaventrite with moderately shallow 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 1/3 laterally, posterior margin of pubescent area produced in middle to 4/5 length of ventrite, in female basal 1/2 of ventrite hydrofuge pubescent. Ventrite 6 shining, in male middle part produced in transverse, narrow, shelflike ridge, weakly emarginate in middle, and bearing few, short setae; posterior to ridge ventrite concave, ventrite with transverse band of sparse setae across posterior 1/2, except absent on ridge and in strongly shining concavity; in female shape simple, with transverse band of sparse setae across posterior 1/2. Male: last ventrite asymmetrical, apex markedly lobiform and setose; last tergite with sparse apical setae and with apicomedian notch into which fits lobe of last ventrite. Female: last ventrite sparsely pubescent, margin rounded; last tergite with very weak apicomedian emargination.

Legs moderately long and slender, combined lengths of metatibia and metatarsus greater than width of head (ratio ca. 43/31), ratio of lengths of metatibia/metatarsus ca. 23/20. Basal 3 protarsomeres, in male, with pad of suction setae. Metacoxa with tiny sharply pointed tubercle on medial surface near trochanter.

Wings fully developed in holotype and all dissected males.

Aedeagus length ca. 0.39 mm; main-piece, in left lateral aspect, with large lobe near large basal ring, apical process long and sharply pointed; distal piece enlarged on right side, forming large hood-like process ( Fig. 44).

Etymology. Named in reference to the small body size.

Distribution. Currently known from southern and southwestern Western Cape Province ( Fig. 97).

Notes. The aedeagi of specimens collected near Cape Town do not have the minute notch near the distal end of the hood-like main-piece, as is present in the holotype ( Fig. 97). Both of the two males from this locality have the emargination of the ridge on the sixth ventrite deeper, resulting in a tiny gibbosity on each side. The holotype is fragmentary, missing many appendages (apparently from decay), as are all of the specimens from the type locality .