Chelicorophium madrasensis Nayar, 1950

Wongkamhaeng, Koraon, Nabhitabhata, Jaruwat & Towatana, Prawit, 2015, Corophiine amphipods of the genera Chelicorophium and Paracorophium from the lower Gulf of Thailand (Crustacea, Amphipoda, Corophiidae, Corophiinae), ZooKeys 505, pp. 35-50 : 39-40

Taxon classification Animalia Amphipoda Corophiidae

Chelicorophium madrasensis Nayar, 1950

Material examined.

Lower Gulf of Thailand, Songkhla Lake (09°18'39.5"N, 99°46'46.4"E), mangrove forest, 1 Feb 2012, leg. R. Puttapreecha, PSUZC-CR-0353 (4♂; 5♀), ZMB28474 (2♂; 2♀)

Type locality.

Madras Coast, India.

Description.

Body subcylindrical; urosomites 1-3 free. Head, rostrum short, not exceeding anterior head lobes; inferior antennal sinus deeply regressed. Antenna 1 slender, one third of body length; peduncle article 1 setose; primary flagellum 12-articulate. Antenna 2 strongly developed in both sexes, much longer than antenna 1; peduncle setose along ventral margin; peduncular segment 4 with strong bidentate posterodistal process; segment 5 shorter, without median tooth; flagellum 3-articulate;

Lower lip (Labium), inner lobe well developed, mandibular lobes medium. Mandible both similar, incisor 3 dentate; left and right lacinia mobilis armed with 2 and 3 dentate respectively; first article of palp with long pilous seta. Maxilla 1, palp longer than outer plate. Maxilla 2, inner lobe shorter than outer lobe; both bearing distal and marginal plumose setae; Maxilliped, inner plate short, apex subacute, inner margin with marginal setae; outer plate reaching apex of palp article 2, setose along both sides; palp segments 2-4 with marginal setae.

Pereon. Gnathopod 1 subchelate-rectipalmate; merus and carpus bearing posteriomarginal plumose setae. Gnathopod 2 merus as long as carpus, with long plumose setae along posterior margin; dactylus tridentate. Pereopods 3 and 4 alike, basis broad (glandular); dactylus subequal to propodus. Pereopod 5 short, basis setose along posterior margin; carpus short, bearing two rows of robust setae along posterior margin. Pereopod 6 basis sparsely setose; carpus short not elongate, bearing two rows of robust setae along posterior margin; dactyl short. Pereopod 7 elongate; basis posteriorly strongly setose on both margins; ischium - carpus sparsely setose; propodus with marginal and distal setae.

Pleon.Urosomites 1-3 free. Uropods 1 and 2 peduncles slightly broadening distally; rami short, straight; outer ramus beset with robust setae. Uropod 3, ramus subequal to peduncle, apically setose. Telson short, truncate, broader than long.

Female. No sexual differences.

Remarks.

Nayar (1950) described Chelicorophium madrasensis from the Madras Coast, India, which is characterized by antenna 2 article 4 inner surface with 2 proximal spines and epimeron 1 smooth and naked. The specimens from the current study are similar to those of Nayar, but the telson is truncated, whereas it is pointed in Chelicorophium madrasensis .

Distribution.

Indian Ocean and Songkhla Lake (current study).