Discozantaena sequentia, Perkins, Philip D., 2005

Perkins, Philip D., 2005, A revision of the South African endemic humicolous beetle genus Discozantaena Perkins and Balfour­Browne (Coleoptera: Hydraenidae), Zootaxa 915, pp. 1-48 : 7-8

Discozantaena sequentia new species

( Figures 1 , 12, 24 )

Type Material. Holotype (male): Cape­Cederberg, jeep track, 1130 m, 32° 28' S, 19° 14' E, sifted, marsh shore, 7 November 1983, Endrödy­Younga (#2055); deposited in the TMSA.

Diagnosis. Recognized by the very narrow explanate margin of the elytra and the non­explanate anterior angles of the clypeus ( Fig. 1 ).

Description. Size (length/width, mm) holotype: body (length to elytral apices) 1.62/ 0.70, head 0.31/0.44, pronotum 0.38/0.61, elytra 0.96/0.70. Dorsum piceus to black; venter dark brown. Frons gibbous between deep oblique foveae, disc moderately shining; decumbent pubescence short, small granule at base of each seta, on disc setae sparse, directed posteriad, near eyes setae denser, directed mediad. Clypeus anterior margin straight, anterior angles obtuse; sculptured and clothed as frons, but less densely. Labrum shining, very finely sparsely setose; apicomedian emargination slightly reflexed.

Pronotum anterior margin weakly arcuate, median 1/2 with narrow hyaline border; anterior angles sharply rounded; sides markedly arcuate to slightly past midlength, then very weakly emarginate before posterior angles; posterior margin arcuate except emarginate near posterior angles. Sides minutely denticulate. Disc quite strongly roundly elevated between anterior semi­Y­shaped and posterior broadly U­shaped transverse impressions, clothed with moderately dense, short decumbent setae, socket of each seta with anterior rim raised to form distinct oblong or 8­shaped granule; granules much denser and larger in impressions than on reliefs and lateral explanate area; surfaces between granules strongly shining.

Elytra with explanate margin very narrow, sides weakly arcuate; sides minutely serrate, pubescence dense, short and overlapping. Ten seriate punctate, series striate impressed, punctures round, those near base contiguous longitudinally, posteriorly becoming little more separated and slightly smaller, each with distinct short decumbent seta, serial setae overlapping, each setal base with minute granule. Intervals impunctate, shining, flat, slightly narrower than serial punctures. Sutural margin raised slightly in posterior 1/2.

Metasternum weakly convex, with very faint, shallow, narrow midlongitudinal impression in posterior 1/2. Thoracic sterna and abdominal ventrites 1–4 and basally 5 clothed with sparse short pubescence; pubescence of metasternum much denser laterally than on disc.

Aedeagus total length 0.35 mm; mainpiece length 0.25 mm; parameres longer than other species in genus, about 1/3 length of mainpiece; mainpiece distal widened area uniquely shaped; flagellum not coiled or spiral, apical 1/4 weakly sclerotized and its shape can therefore vary depending on preparation; collar is either absent or indistinguishable from base of flagellum; mainpiece distal widened area has a raised part that could be homologous with, and plesiomorphic condition of, collar ( Fig. 12).

Etymology. Latin, sequentia (= sequence); the combination of apotypic vs. plesiotypic character states of this species reveals part of the sequence of development of derived characters in the genus.

Distribution. Presently known only from the type locality in the Cederberg mountains of the western Cape Province ( Fig. 24 ).

Figures

FIGURE 1. Discozantaena sequentia holotype. Dorsal and lateral habitus.

FIGURES 23 – 25. Discozantaena distribution maps. — 23. All Discozantaena collecting sites. — 24. D. sequentia. — 25. D. endroedyi.