Parhydraena brevipalpis (Régimbart)

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 : 15-16

Parhydraena brevipalpis (Régimbart)

( Figs. 34, 36, 103)

Hydraena brevipalpis Régimbart, 1906: 276 .

Parhydraena brevipalpis (Régimbart) ; Orchymont, 1937: 457.

Parhydraena brevipalpis (Régimbart) ; Balfour-Browne, 1954: 97 (lectotype designation).

Type material. Lectotype (male): Kenya, Londiani , 2500 meters, Mau Escarpment, Ch. Alluaud, x.1903, 0° 40' S, 36° 2' E [labels: " Afr. Or. Angl. Londiani, 2500 m. (Mau Escarpment). Ch. Alluaud. x.1903 // Holo- Type [sic] male // Parhydraena brevipalpis Rég. J. Balfour-Browne vid. Designated holotype [sic] // Aedeagus drawn by P. D. Perkins 2008 // DIGITAL IMAGE captured 2008 P. D. Perkins "]. Deposited in the MNHN.

Material examined (34): Kenya: Same data as lectotype (8 MNHN) ; 10 mi. S. Nanyuki , 0° 7' S, 37° 5' E, 5.ii.1968, P. J. Spangler (7 USNM) ; 30 mi. NW Nairobi , 1° 1' S, 37° 6' E, 13.i.1968, P. J. Spangler (1 USNM) ; Afr. Or. Angl. (Rift Valley) Naivasha , elev. 1900 m, 0° 46' N, 36° 21' E, xii.1911, Alluad & Jeannel (1 MCZ) ; Lake Nakuru, 3 km above Egerton, Njoro river , 0° 19' S, 36° 3' E, 5.ii.1994, Moog et al. (4 NMW) ; Lake Nakuru, nr. Egerton, Njoro , 0° 19' S, 36° 4' E, 9.ii.1994, Moog et al. (3 NMW) ; Mais. forest Kinangop, Mt. Aberdare , vers’ ouest, elev. 2600 m, 0° 27' S, 36° 23' E, 1932–1933, P. A. Chappuis & R. Jeannel (1 MCZ) ; Nanyuki Forestry Station , 0° 2' S, 37° 4' E, 5.ii.1968, P. J. Spangler (1 USNM) ; Ol Kalou , E Nakuru, 0° 16' S, 36° 22' E, 28.x.1995, Wewalka (K5) (7 NMW) ; Tanzania: Afrique or. allemande, Kilimanjaro versant sud-est, lisiere super. des forêts, Bismarck-Hügel , elev. 2700–2800 m, 3° 16' S, 37° 30' E, iv.1912, Alluaud & Jeannel (1 MCZ) .

Differential diagnosis. Differentiated from P. lancicula by the less striate-impressed elytra, the larger size (length ca. 1.97 vs. 1.76 mm), the narrower body form, the longer maxillary palpi (palpus length/head width ca. 0.64 vs. 0.54), and the very different aedeagus ( Fig. 34, 36, 50, 52). Males additionally distinguished from those of P. lancicula by the non-modified 5th abdominal ventrite. Habitus similar to P. seriata , but the maxillary palpi are longer in that species, and the male genitalia of the two species differ markedly ( Figs. 43, 45).

Description. Size (length/width, mm) lectotype: body (length to elytral apices) 1.97/0.85; head 0.32/0.53; pronotum 0.48/0.72, PA 0.61, PB 0.62; elytra 1.22/0.85. Head and disc of pronotum dark brown to piceous, remainder of dorsum brown, disc of pronotum darker than surrounding area (surrounding area light brown in slightly teneral lectotype); legs brown; maxillary palpi light brown, distal 1/2 of last mere not darker than remainder of palpus.

Head with eyes moderately large, in dorsal aspect 9 convex facets in longest series. Ocelli distinct round small shining, each located at base of shallow oblique interocular fovea. Frons on disc moderately finely punctate, ca. 1xef, interstices effacedly microreticulate, weakly shining, 2–4xpd; area between interocular foveae and eye microreticulate, punctate, dull. Clypeus markedly microreticulate and indistinctly punctate, punctures much smaller and less dense than those of frons disc, except anterior margin shining. Labrum weakly shining, apicomedially notched to form rounded lobe on each side; laterally fringed with short arcuate setae. Maxillary palpi moderately long, combined lengths of meres less than width of head (ratio ca. 23/36); ratios of meres 2–4 ca. 7/5/11. Mentum and submentum sparsely finely punctulate, microreticulate.

Pronotum, except discal relief, densely punctate, some punctures confluent, each 'puncture' with anterior margin extended posteriorly as narrow ridge, dividing puncture into a pair of two smaller punctures, each of which ca. 1xef or slightly smaller, short recumbent or decumbent seta arising from posterior extreme of dividing ridge; anterior margin weakly arcuate, median 1/3 with extremely narrow hyaline border. Anterior angles obtuse, moderately widely rounded. Sides rounded, widest at about middle, behind middle gradually attenuate, very weakly, if at all, sinuate. Posterior angle obtusangulate. Disc with impressions moderately deep, broadly U-shaped, punctures deeper and denser in impressions, many confluent; sparser on discal relief, interstices shining, 1–3xpd; shallow wide impression at each posterior angle. Sculpture laterally subrugose, dull.

Elytra rather dull, elongate-ovate, sides weakly arcuate, margins narrow, distinct from shoulder for 4/5 of length, sutural angle slightly more acute in female than in male. Ten-seriate punctate, only first series striateimpressed, in distal 1/2; punctures ca. 2–3xef, longitudinally separated 0.5–1xpd, becoming finer and shallower on apical declivity. Interval width 1–2xpd, weakly shining, surface slightly uneven. Both series and intervals each with unilinear row of minute granules, each granule at its posterior side with very short recumbent seta, setae similar in length and density to setae of serial punctures.

Metasternum 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, band becoming narrower toward midline, then widened in middle to 1/2 length of ventrite, in female basal 2/5 to 1/2 of ventrite hydrofuge pubescent, not widened in middle; shining part of ventrite 5 very sparsely pubescent in both sexes. Ventrite 6 very weakly, effacedly microreticulate, shining, in male shallowly concave in middle; in female shape simple, with transverse band of sparse setae across posterior 1/2. Male: last ventrite symmetrical, apex rounded, weakly produced in small lobe that fits in notch of last tergite; last tergite produced as very small points on each side of apicomedian notch. Female: last ventrite sparsely pubescent, margin rounded; last tergite with small tuft of setae on each side of apicomedian emargination.

Legs moderately long and slender, combined lengths of metatibia and metatarsus greater than width of head (ratio ca. 49/36), ratio of lengths of metatibia/metatarsus ca. 30/19. Basal 3 pro- and mesotarsomeres, in male, with pad of suction setae.

Wings fully developed in holotype and all dissected males.

Aedeagus length ca. 0.38 mm; main-piece wider in lateral view than in ventral view; in ventral view, with short sharply pointed process on left side; distal piece with three lobes, lobe on right side strongly sclerotized, middle lobe adjacent to right lobe, weakly sclerotized, lobe on left side slender, separated from other lobes, forming support for gonopore bearing duct on ventral surface ( Fig. 36).

Distribution. Currently known from several localities in southwestern Kenya, and one locality near Mount Kilimanjaro, Tanzania ( Fig. 103).

Notes. The aedeagi of the specimen from Kinangop and the specimen from Kilimanjaro differ slightly from that of the lectotype: the main-piece in lateral view is narrower, the middle (lightly sclerotized) lobe of the distal piece is more sharply pointed at the apex, and the gonopore bearing tube terminates slightly before the tip of the process that supports it. Some specimens are more darkly colored than the lectotype (which appears to be slightly teneral; Fig. 34), with much less contrast between the color of the pronotal disk and that of the surrounding area .