Streptocephalus echinus Bond, 1934

Velu, Chinavenmeni S & Munuswamy, Natesan, 2005, Updated diagnoses for the Indian species of Streptocephalus (Crustacea: Branchiopoda: Anostraca), Zootaxa 1049, pp. 33-48 : 39

Streptocephalus echinus Bond, 1934

Material examined. Guntur (16°18N, 80°29E), Poondi (13°02N, 80°10E), Chengleput (12°42N, 80°01E). Accession numbers are DZ/NM/FS/130 to 132.

Measurements: 13 males (14.6–16.8); 26 females (14.2–15.6).

Description: Male­First antennae project laterally and point towards posterior end ( Fig. 3 A, D). Second antennae have sub­cylindrical proximal segment, distal segment slender, directed posterior medially. Antennal appendage long, peduncle stout, “S” curved, anterio­lateral sub­crenulate papillae are absent ( Fig. 3 B, C). Peduncle bears a lateral row of slender spines at the distal curve ( Fig. 3 D). Cheliform hand elongate; thumb shorter than peduncle, bears an arcuate spur and no shoulder opposite the spur. Finger as long as peduncle, bifid, with posterior ramus serrated at basal and distal end and arcing interiorly ( Figs. 3 B, C). Anterior ramus spinose arranged as series of long spines ( Figs. 3 B). Bases of proximal portion of penes each with a lateral linguiform projection, proximal nonretractile part of penes bears an anteriorly curved medial projection with spines on the anterior surface ( Fig. 3 E). Cercopods are lanceolate, setiferous to tip with fine setae.

Female Second antennae are simple, flat, rounded at the tip ( Fig. 3 D). Brood pouch slender, extends to third and forth abdominal segment ( Fig. 3 F).

Cyst The cyst surface is covered with series of pentagonal shaped polygons. The ridges are raised, surface covered with pores and centered fields are smooth and depressed without pores ( Figs. 3 G, H).

Remarks Streptocephalus echinus Bond, 1934 can be differentiated from others based on the following structures: The second antennae of the male has serration at the anterior part of the anterior ramus; the anterior­lateral subcranulate papillae are absent; the thumb is shorter than the peduncle and finger and it has no shoulder on the thumb. The cyst surface is covered with pentagonal shaped polygons and smooth, depressed centered field with no pores.

Figures

FIGURE 3. Streptocephalus echinus BOND. A. Male, lateral view of head. B. Male antennae, lateral view. C. Male antennae, medial view. D. Female, ventral view of head. E. Ventral view of male genital region, arrow showing the spines on the protuberances. F. Female abdomen with brood­pouch, lateral view. G. Cyst. H. Higher magnification showing ridges, depression and pores.