Kemponia platycheles ( Holthuis, 1952a )

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 : 532-534

Kemponia platycheles ( Holthuis, 1952a)

( Figs. 18 , 19 )

Periclimenes (Harpilius) platycheles Holthuis, 1952a: 85 , Fig. 33 ; Miyake & Fujino, 1968: 409, Figs. 3 c-f.

Periclimenes platycheles - Chace & Bruce, 1993: 120; Müller, 1993: 104; Li, 2000: 226, Fig. 299; De Grave, 2000: 138; Bruce, 2003: 240.

Kemponia platycheles – Bruce, 2004: 18 .

Material examined. – 4 males (CL 4.0, 4.0, 4.0, 3.6 mm), 2 ovig females (CL 3.5, 3.4 mm), CN 92 C-182D, Xincun Harbour , Hainan Is., 1-3m, with Acropora sp. , coll. X. Li & V. Neumann, 27 Mar.1992 .

Diagnosis. – Rostrum very long and slender, exceeding end of scaphocerite, distal half up-turned, with 1 + 6-8/5-8 teeth, posteriormost dorsal tooth slightly posterior to level of hepatic spine. Carapace without supraorbital spine, orbital angle broadly rounded. Scaphocerite narrow, with lateral margin deeply concave, distolateral tooth exceeding truncate distal margin of lamella. Mandible with incisor process tapering distally, with 3 marginal teeth. Telson with posterior margin with acute median process, with three pairs of posterior mariginal spines, intermediate pair robust and very long. Second pereiopods sexual dimorphic, unequal, long, exceeding scaphocerite with entire carpus and chela; merus with sharp distal tooth on flexor margin; carpus expanded distally, 0.5 to 1.75 times as long as palm, with 2 sharp distal spines in female and 3 in male; fingers 0.33 to 0.5 as long as palm, proximal 0.6-0.7 of cutting edges denticulate, tips strongly curved; dactyl slightly twisted, upper margin with sharp flange along external lateral side, outer margin sometimes concave, in which case fixed finger convex. Ambulatory pereiopods with dactyl is simple; propodus with spinules on flexor margin; fifth exceeding scaphocerite. Uropod with exopod has one disto-lateral movable spine.

Distribution. – Previously reported from Indonesia and Palau Islands.

Remarks. – See “Remarks” under Kemponia grandis ( Stimpson, 1860) . The present specimens agree closely with the original description, but the carpus of their second pereiopods are distinctly shorter than the palm, and also stouter than that illustrated by Holthuis (1952). Thanks to the kindness of Dr. Dirk Platvoet, the type material has been available for re-examination. The holotype is in good condition, but lacks the right first pereiopod, the left third pereiopod, the left first pereiopod lacks the distal carpus and chela, the left second pereiopod and the left second pleopod are detached from the body; the paratype lacks most of the pereiopods and pleopods, only the detached right first pereiopod, right second pereiopod and right first pleopod are present. The maxillula, maxilla, first to third maxilliped on right side have been dissected off, but the right mandible missing. In comparison, our samples are very similar to the types except for the second pereiopods and rostrum. In our samples, all the right second pereiopods are lost, except for one male, which has a short and regenerating right second pereiopod, so it is uncertain if the left second pereiopods are the major or minor limb, but the second pereiopods are distinctly sexually dimorphic, as De Grave (2000) noted, much larger in the males than in females, and the carpus in the male is shorter and stouter than that of the female. The second pereiopods in our two female specimens are similar to those of the holotype in size. The fingers of the second pereiopods in the males of our samples are different, the cutting edges armed sometimes with 2 large opposing teeth, sometimes with many small teeth on proximal 0.6-0.7 of the finger length. Concerning the variations in the proportional length of carpus against the palm and denticulations of cutting edges of the fingers of the second pereiopopds, the material of Miyake and Fujino (1968: 410, Figs. 3 c-f) on the basis of their specimens, and their illustrations ( Figs. 3d, e ) which may based on their male specimen, are very close to the condition of two of our four males. It is considered that the differences appear to fall within the range of variation of this species. In three specimens with perfect rostra, the rostral formulae are respectively 1+6/6, 1+7/8 (males), and 1+8/8 (female). The female has more rostral teeth than in the types (1+6/4, 1+6/6). Besides the sexual dimorphism in the second pereiopods and rostrum, the size of males is larger than females: in our samples, the carapace lengths of males are 3.6-4.0, average 3.9 mm, those of females are 3.4-3.5. The species has another unusual features, the posterior margin of telson in the holotype and all our specimens has a long and acute median process, as illustrated by Miyake and Fujino (1968: 408, Fig. 3f ); a finger-like process on the fourth thoracic sternite indicates that the species belong to the “ Periclimenes grandis species group sensu lato ( Bruce, 1987b)”.

De Grave (2000) pointed out that the material from Lizard Island ( Australia) recorded by Bruce (1983b, 1992) may belong to a closely related, as yet un-described species. Thanks to Dr. Penny Berents, who kindly sent the specimens from Lizard Island, Queensland, deposited in Australian Museum, so that the first author (XLi) had chance to check them. The female (no. P. 39292) is very close to the paratype of Kemponia platycheles , with the rostrum almost horizontal, carpus of second pereiopod long, and the median process on the posterior margin of the telson round, but the chelae of the first pereiopods are more slender than those of the paratype, as illustrated by Bruce (1992: 63, Fig. 15F ); the ovigerous female (No. P. 39304) is close to the holotype of K. platycheles , with the rostrum distinctly up-curved on the distal half, second pereiopod with a long carpus and cutting edges of fingers with two large teeth, and the median process on the posterior margin of the telson acute; the male (No. P. 39304) is close to our samples which with the rostrum dinstinctly up-curved on the distal half, and the median process of the posterior margin of the telson is acute, unfortunately, both the second pereiopods of the male are regenerating. That is to say, the material from Lizard Island are very similar to K. platycheles in many characters, except for the first pereipod, as noted by Bruce (1992) and De Grave (2000).

Figures

Fig. 18. Kemponia platycheles (Holthuis, 1952). a, carapace and anterior appendages, lateral view; b, mandible; c, telson and uropod, dorsal view; d, tip of telson.

Fig. 19. Kemponia platycheles (Holthuis, 1952). a-d, major (left) 2nd pereiopod; b, same, tip of merus and carpus; c, d, same, fingers; e, regenerate 2nd pereiopod.

Fig. 33. Periclimenes tosaensis Kubo, 1951. a, anterior region of carapace and rostrum, lateral view; b, 2nd pereiopod; c, dactyl and apex of 3rd pereiopod.

Fig. 3. Leander tenuicornis (Say, 1818). a, carapace and rostrum, lateral view, female; b, same, male; c, antennule.

Fig. 15. Conchodytes biunguiculatus (Paulson, 1875). a, anterior carapace and rostrum, lateral view; b, chela of 2nd pereiopod; c, dactyl of 3rd pereiopod; d, telson.