Streptocephalus longimanus Bond, 1934

Padhye, Sameer M. & Lazo-Wasem, Eric A., 2018, An updated and detailed taxonomical account of the large Branchiopoda (Crustacea: Branchiopoda: Anostraca, Notostraca, Spinicaudata) from the Yale North India Expedition deposited in the Yale Peabody Natural History Museum, Zootaxa 4394 (2), pp. 207-218 : 209

Streptocephalus longimanus Bond, 1934

Fig.2 (A & B)

Material examined. YPM IZ 003590.CR: Eggs from the female allotype.

Locality. Madras Presidency, Mahabalipuram [as per Bond (1934)] (Mahabalipuram, Tamil Nadu, India). Original label data : India, Punjab, Rawalpindi District , Sohara G. E. Hutchinson, coll. 3-III-1932 (Sohara, Rawalpindi District, Pakistan).

Comments. Adult morphology matches that of the descriptions of Bond (1934) and Velu and Munuswamy (2005). Eggs 202 µm and 208 µm (n=2), with large regular polygons, each polygon with 4–6 angles ( Fig.2A ). Polygon number = 12 and 13; wh: dw ratio =0.3–0.5. Polygonal walls broadly triangular, upper edges of the walls distinct. Floors of the polygons nearly flat with faint dimples ( Fig. 2B ). The eggs, when compared with other Indian streptocephalids, are characteristically unique with fewer well-defined polygons with thicker and shorter triangular walls (for more details of egg morphology of other Indian streptocephalids, refer to Velu & Munuswamy (2005) and Padhye et al., (2016)). The polygonal walls of the eggs from the Yale allotype show a different morphology from the eggs reported by Velu & Munuswamy (2005) with the former having more triangular and relatively thinner walls. The polygon number also seemed to be fewer in the allotype but showed a similar surface of the polygonal base. It has been documented that egg surface morphology varies between different populations of the same species and sometimes even between females of same population in Indian streptocephalids (Padhye et al., 2016) and hence is not taxonomically informative by itself. This structure thus represents one more egg surface ornamentation pattern in S. longimanus .

Figures

FIGURE 2. Streptocephalus longimanus. A & B, eggs (Scale bars: A:0.2 mm; B: 0.1 mm)