Sharphydrus coriaceus ( Régimbart, 1895 )

Bilton, David T., 2013, A taxonomic revision of South African Sharphydrus, with the description of two new species (Coleoptera: Dytiscidae: Bidessini), Zootaxa 3750 (1), pp. 26-36 : 27

Sharphydrus coriaceus ( Régimbart, 1895)

Within the genus this species can be readily distinguished by the lack of elytral keels ( Fig. 1D ), and the characteristic male genitalia, in which the lateral lobes are apicoventrally directed ( Fig. 2D ). Originally described from Cape Town, S. coriaceus has subsequently been found to be widespread in the South African Cape, occurring in Western, Eastern and Northern provinces ( Fig. 4 ). Omer-Cooper (1966) lists the species from Cape Town, Milnerton, Bridgetown, Piquetberg, Somerset West, Worcester, Robertson, Hermanus, Rivierzonderend, Hanover, Richmond, Murraysberg, Graaf Reinet, Pearston, Somerset East, Colesberg and Uitenhage. To these localities I can add the following, based on material I have studied or collected: Nov. 1931, Prince Albert Road, R. E. Turner leg. (1ex., NHM); 11/iii/1954, Caledon District, Zonder End River, below weir at Genadendal, J. Balfour-Browne leg. (1 ex., NHM); 11/xi/1949, Philadelphia, running stream, gravel, B. Malkin leg. (2 ex., NHM); 18/xi/1949, Philadelphia, B. Malkin leg. (3 ex., NHM); 26/x/1949, Oudtshoorn, Olifants River, B. Malkin leg. (4 ex., NHM); 27/vii/1954, Kalabaskraal, roadside pond, much Juncus and Nitella, J. Balfour-Browne leg. (1 ex., NHM); 19/ix/ 2010 Kamiesberg, stream on Witwater-Langkloof road ca. 1 km S of junction, D. T. Bilton leg. (1♀, CDTB); 25/xi/ 2011, Oorlogskloof River on R27 road ca. 20 km E of Nieuwoudtville, D.T. Bilton leg. (1♀, CDTB); 2/x/2013, Tankwa River on R355 road in Tankwa Karroo, D.T. Bilton leg. (2♀, CDTB). On the basis of current records, S. coriaceus appears to be most frequent in semi-arid areas, both in the winter rainfall zone and outside it. It is apparently commonly found in pools in drying streams and rivers, and can occur in brackish water, as it did in the Oorlogskloof and Tankwa rivers.

Figures

FIGURE 1. Habitus of A) Sharphydrus brincki sp. nov. B) S. kamiesbergensis sp. nov. C) S. capensis. D) S. coriaceus. Dorsal and lateral views. Scale bar = 1 mm.

FIGURE 2. Male genitalia of Sharphydrus species: median lobe in lateral and ventral view, right paramere of: A) S. brincki sp. nov.; B) S. kamiesbergensis sp. nov.; C) S. capensis; D) S. coriaceus. Scale bar = 0.5 mm

FIGURE 4. Distribution of Sharphydrus species in South Africa: yellow symbols S. brincki, green symbol S. kamiesbergensis, red symbols S. capensis, white symbols S. coriaceus. Closed circles indicate specimens examined, open circles records from the literature.