Palaemon sewelli ( Kemp, 1925 )

Li, Xinzheng, Bruce, Alexander J. & Manning *, Raymond B., 2004, Some Palaemonid Shrimps (Crustacea: Decapoda) From Northern South China Sea, With Descripitions Of Two New Species, Raffles Bulletin of Zoology 52 (2), pp. 513-553 : 525

Palaemon sewelli ( Kemp, 1925)

( Fig. 12 )

Leander sewelli Kemp, 1925: 299 , Figs. 9 , 10.

Palaemon (Palaemon) sewelli - Holthuis, 1950: 8.

Palaemon sewelli - Liu, Liang & Yan, 1990b: 240, Fig. 32 .

Material examined. – 1 female, CN 54-394 - 5 A, Beibu Bay, off Hepu, Guangxi Province, coll. J. Y. Liu, 30 Dec.1954 .

Diagnosis. – Rostrum short and deep, dorsal margin straight, horizontal, with 3-5 + 8-14 (usually 4 + 10-12) + 0-2/3-5 teeth. Proximal segment of antennular peduncle with distolateral tooth reaching middle length of second segment; free part of shorter ramus of dorsal antennular flagellum longer than fused portion. Mandible with well developed 3- segmented palp.

Description. – Rostrum short and deep, slightly shorter than carapace, dorsal margin straight, horizontal, with 3-5 + 8-14 (usually 4 + 10-12) teeth, excluding 0-2 small subapical teeth; ventral margin with 3-5 teeth. Carapace with branchiostegal spine, subequal with anteral spine in size, its tip slightly over-reaching the anterior margin of carapace, branchiostegal groove distinct. Abdomen smooth, length of sixth somite slightly less than 1.5 times as long as fifth, height subequal to length of fifth somite. Telson about as long as fifth and sixth abdominal somites together, with 2 pairs of small dorsolateral spines on posterior half of the length, posterior margin with pair of long intermedian spines and pair of short lateral spines. Proximal segment of antennular peduncle with distolateral tooth reaching middle length of second segment; free part of shorter ramus of upper antennular flagellum longer than fused portion. Scaphocerite reaching to between rostral tip and distal end of antennular peduncle, distolateral tooth reaches about the end of lamella. Mandible with well developed 3-segmented palp. First pereiopod reaching to about end of antennular peduncle, carpus slightly longer than chelae. Second pereiopod over-reaching end of scaphocerite by 0.5 to 0.67 of palm; chela as long as 1.5 times of carpus, palm subequal to fingers in length, 3 times of its width; carpus 5 times as long as distal width; merus 7 times as long as width, 1.1-1.2 times of carpus. Ambulatory pereiopods short and stout, with movable spines on posterior border; third pereiopods over-reaching end of scaphocerite with dactyl, dactyl slightly longer than half propodus, as long as carpus; fifth pereiopod with dactyl slightly longer than that of third pereiopod, propodus 1.75 times as long as carpus, merus slightly longer than propodus, longer than 10 times width. The fresh specimens were covered with small red spots on lateral surfaces, the dorsal surface from carapace to middle of telson with a whitish stripe.

Distribution. – India, Burma, South China Sea. In shallow water, estuary or brackish waters.

Figures

Fig. 12. Palaemon sewelli (Kemp, 1925). a, carapace and rostrum, lateral view; b, left mandible; c, right 2nd pereiopod; d, right 3rd pereiopod.

Fig. 9. Palaemon debilis Dana, 1852. a, carapace and rostrum, lateral view; b, antennule; c, mandible; d, 1st pleopod, male.

Fig. 32. Periclimenes sinensis Bruce, 1969. a, anterior region of carapace and rostrum, lateral view; b, right 1st pereiopod; c, right 2nd pereiopod; d, same, fingers.