Parhydraena seriata Balfour-Browne, 1954

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 : 21-23

Parhydraena seriata Balfour-Browne, 1954

( Figs. 43, 45, 93)

Parhydraena seriata Balfour-Browne, 1954: 96 .

Parhydraena seriata Balfour-Browne ; Perkins and Balfour-Browne, 1994: 126.

Type material. Holotype (male): South Africa : Eastern Cape Province, Albany District, Gowie’s Kloof, 33° 18' S, 26° 32' E, 6.viii.1939, J. Omer-Cooper [labels: "TYPE// SOUTH AFRICA Albany Dist. Gowies

Kloof 6.viii.39.//J. Omer Cooper coll.//Brit. Mus. 1939-625.//Aedeagus drawn by P. D. Perkins 1992// DIGITAL IMAGE captured by P. D. Perkins 2008 // Parhydraena (s str.) seriata Type J. Balfour-Browne det."]. Deposited in the BMNH.

Material examined (161): South Africa: Eastern Cape Province, Albany District, Gowie’s Kloof , 33° 18' S, 26° 32' E, 6.viii.1939, J. Omer-Cooper (58 BMNH) ; Amatole, Pirie Forest Station , shore washing, 32° 43' S, 27° 17' E, 8.xii.1987, Endrödy-Younga (#2563) (7 TMSA) ; Ciskei, Amatole, Pirie For. , sift. wet forest ditch, 32° 43' S, 27° 17' E, 8.xii.1987, Endrödy-Younga (#2561) (18 TMSA, 6 TMSA) ; Grahamstown, Teafontein Farm , 33° 18' S, 26° 32' E, 5.viii.1939, J. Omer-Cooper (1 BMNH, 20 BMNH) ; Piggott Bridge Road , 33° 18' S, 26° 32' E, 10.ii.1939, J. Omer-Cooper (4 BMNH) ; Upper Wildebees River ( Gatberg Rd. ), marginal vegetation in current, 31° 12' S, 28° 5' E, 12.v.1990 (1 AMG) ; Wilderness NP, Langvlei, Malachite bird hide, Juncus krausi and bush litter sievings, 33° 59' S, 22° 41' E, 30.xi.1996, B. & M. Uhlig (6 ZMHB) ; Gauteng, Olifantsvlei, south of Johannesburg (OLF 86A), 26° 18' S, 28° 1' E, (5 AMG) ; KwaZulu-Natal Province, Little Mooi River, Yorkshire Wolds , ex. marginal vegetation in current, 29° 18' S, 29° 46' E, 10.vi.1998, F. de Moor & C. Dickens (Moi 103 AL) (1 AMG) ; Mpumalanga Province, c. Transvaal, Roodeplaat Dam , shore washing, 25° 37' S, 28° 23' E, 14.viii.1974, Endrödy-Younga (#359) (1 TMSA) ; Mt. Sheeba , under river stones, 24° 51' S, 30° 45' E, 27.xi.1986, Endrödy-Younga (#2322) (1 TMSA) ; S. Transvaal, Roberts Drift , Vaal R., sifted flood debris, 27° 2' S, 29° 2' E, 8.x.1973, Endrödy-Younga (#190) (1 TMSA) ; Vaal R., Stn. V.D. 21, marginal vegetation; NIWR-VAL 884J, 26° 49' S, 30° 8' E, 21.x.1959, (1 AMG) ; Vaal River where crossed by Ermelo / Amsterdam road, VAL Stn. 2A, 26° 34' S, 30° 12' E, (6 AMG) ; Western Cape Province, 20 km W George , elev. 50 m, 33° 59' S, 22° 18' E, 3.i.1994, Wewalka (7 NMW) ; 8 mi. E. Wilderness , 33° 58' S, 22° 43' E, 13.iii.1968, P. J. Spangler (8 USNM) ; Cape of Good Hope Nature Reserve , 34° 16' S, 18° 25' E, 7–10.iii.1968, P. J. Spangler (1 USNM) ; Wilderness NP, stream in road to Swartvlei , 33° 59' S, 22° 37' E, 22.iii. 2001, I. Ribera & A. Cieslak (8) (1 MNCN) ; Zimbabwe: Chimanimani NP, Southern lakes, elev. 1380 m, 19° 55' S, 33° 1' E, 31.vii.1994, Mazzoldi (7 NMW) .

Differential diagnosis. Similar in dorsal habitus and maxillary palpus length to P. maureenae ; distinguished therefrom by the smaller size (ca. 1.75 mm vs. 2.00 mm), the narrower elytral intervals, and the denser punctation of the frons and pronotal relief ( Figs. 38, 43, 46). Males of P. seriata are distinguished from the externally similar P. ancylis by the different modification of ventrite 6. The aedeagi of the three species differ markedly, and should be examined for reliable determinations ( Figs. 40, 45, 48). The holotype ( Fig. 43) is teneral; mature specimens are darker, with much less difference in the color of the pronotal disc and surrounding areas.

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.75/0.82; head 0.29/0.50; pronotum 0.44/0.69; elytra 1.19 /0.82. Head and disc of pronotum dark brown to piceous, remainder of dorsum brown, lateral areas of pronotum slightly lighter (holotype teneral); legs brown; apex of distal mere of maxillary palpus 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 distinctly finely punctate, ca. 1xef, interstices effacedly microreticulate, moderately shining, 1–2xpd; area between interocular foveae and eye microreticulate, punctate, dull. Clypeus dull, microreticulate and indistinctly punctate, punctures smaller and less dense than those of frons disc, except anterior margin shining. Labrum dull, apicomedially emarginate to form rounded lobe on each side; laterally fringed with short arcuate setae. Maxillary palpi moderately long, combined lengths of meres slightly less than width of head (ratio ca. 29/33); ratios of meres 2–4 ca. 11/6/12. Mentum and submentum sparsely finely punctulate, microreticulate.

Pronotum with anterior margin weakly arcuate, median 1/3 with extremely narrow hyaline border. Anterior angles obtuse, widely rounded. Sides rounded, widest just before middle, behind middle gradually attenuate, very weakly sinuate. Posterior angle obtusangulate. Disc with posterior impression slightly deeper, broadly U-shaped, with median anterior margin more abrupt where disc feebly elevated; punctation denser in impressions, some punctures confluent, punctures sparser, 1–3xpd, on relief where interstices strongly shining; shallow wide impression at each posterior angle. Sculpture laterally subrugose, dull. Each puncture with anterior margin extended posteriorly as narrow ridge, dividing puncture into a pair of two smaller punctures each of which smaller than eye-facet, short recumbent or decumbent seta arising from posterior extreme of dividing ridge.

Elytra elongate-ovate, sides subparallel, margins distinct from shoulder for 4/5 of length, sutural angle more rounded in female than in male, in some females dehiscent at suture. Ten-seriate punctate, only first series striate-impressed in distal 1/2, punctures ca. 2xef, longitudinally separated 0.5–1xpd, becoming finer and shallower on posterior declivity. Interval width 1–2xpd, shining, each with unilinear or 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.

Metasternum with median elongate oval impression in basal 1/2, midlongitudinal shining carina between anterior extreme of oval impression and mesoventral intercoxal process. Metasternum 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 3/4 length of ventrite, in female only basal 1/3 of ventrite hydrofuge pubescent; shining part of ventrite 5 very sparsely pubescent in both sexes, in male slightly swollen. Ventrite 6 microreticulate but shining, in male anterior part gradually swollen, middle shallowly impressed, transverse wide irregular band of sparse setae across ventrite, in female shape simple, transverse band of setae narrower. Male: last ventrite asymmetrical, apex lobiform and setose; last tergite with tuft of setae on each side of 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 apicomedian emargination.

Legs moderately long, combined lengths of metatibia and metatarsus greater than width of head (ratio ca. 44/33); ratio of lengths of metatibia/metatarsus ca. 27/18. Basal 3 pro- and mesotarsomeres, in male, with pad of suction setae.

Wings fully developed in holotype and all dissected males.

Aedeagus length ca. 0.40 mm; distal piece with large, strong process, subapically angulate and sharply pointed at tip; main-piece wider in ventral than lateral view ( Fig. 45).

Distribution. This species has a very wide but very sparse distribution pattern, in southern, eastern and northeastern South Africa ( Fig. 93). In addition, there is one disjunct locality (not plotted on map) in Chimanimani National Park, Zimbabwe.