Streptocephalus longimanus Bond, 1934

Velu, Chinavenmeni S & Munuswamy, Natesan, 2005, Updated diagnoses for the Indian species of Streptocephalus (Crustacea: Branchiopoda: Anostraca), Zootaxa 1049, pp. 33-48 : 39-42

Streptocephalus longimanus Bond, 1934

Materials investigated. Kovalam (13°04N, 80°18E), Chengleput (12°42N, 80°01E). Measurements. 9 males (15.3–16.9); 5 females (14.2–15.3). Accession numbers are DZ/NM/FS/141–142.

Description: Male­First antennae is slender, coiled at distal end and hidden under the compound eye ( Fig. 4 A). Second antennae directed posteriomedially, proximal segment sub­cylindrical, distal segment slender. Antennal appendage long with five anterio­lateral sub­crenulate papillae proximal to the first curve, the first one being large compared to others ( Fig. 4 B). Peduncle stout, S­curved, longer than second antennal proximal segment, and bears a lateral row of slender spines at the distal curve ( Fig. 4 B, D). “Hand” elongate cheliform; thumb longer and equal to finger, bearing an arcuate spur, and no shoulder opposite the spur ( Fig. 4 C). Finger is long, bifid with posterior ramus smooth and arcing anteriorly. Anterior ramus of finger with spines arranged as a series of shorter spines ( Fig. 4 C, D). Thoracic and abdominal appendages are smooth. Penes have lateral linguiform projections at the base of proximal portion. Proximal non­retractile part of penes bears an anteriorly curved medial projection with no spines on the anterior surface ( Fig. 4 G). Cercopods are lanceolate, setiferous to tip with fine setae and a groove in the middle on the entire length ( Fig. 4 I).

Female. Second antennae is simple, flat and rectangular ( Fig. 4 E, F). Brood pouch extends to the forth abdominal segment with a blue streak on its ventral surface ( Fig. 4 H).

Cyst The cyst surface is covered with a series of pentagonal polygons. The ridges are raised, broad and with centered depressed fields ( Figs. 4 J, K). The surface is covered with small pores both in ridges and depressed fields ( Fig. 4 K).

Remarks. Streptocephalus longimanus Bond, 1934 can be separated from other species on the following characters: The second antennae of male has small spines on the posterior ramus, the thumb being equal to the finger; the penes has medial projections with a smooth surface; cercopods lanceolate with a groove. A bluish streak on the brood pouch is seen in the female. Cyst surface is covered with pentagonal polygons and has pores all over.

Figures

FIGURE 4. Streptocephalus longimanus BOND. A. Male, lateral view of head. B. Protuberance C. Male antennae, lateral view. D. Medial view of male antennae. E. Female, ventral view of head. F. Single antennae. G. Ventral view of male genital region, arrow showing the smooth protuberance. H. Lateral view of female abdomen with brood­pouch. I. Male, Telson. J. Cyst. K. Details of cyst showing the ridges, depression and pores.