Bathypalaemonetes chani, Cleva, 2004

Cleva, Régis, 2004, Stylodactylidae And Bathypalaemonellidae From Taiwan (Crustacea: Decapoda: Caridea), Raffles Bulletin of Zoology 52 (2), pp. 497-511 : 507-510

Bathypalaemonetes chani , new species

( Figs. 4 , 5, 6h )

Material examined. – Holotype- 1 ov. female 15 mm, (NTOU-H- CD132-1), “ TAIWAN 2001”, R. V. “OCEAN RESEARCHER 1”, st. CD 132, 22 20.98’N- 120 6.73’E, 690-700 m, 21 Nov.2001 .

Description. – See Figs. 4 and 5. Carapace integument thick and firm, covered with numerous pairs of triangular setae, as in B. pilosipes . Rostrum well developed, particularly large in its middle (about 0.14 of the carapace length), tip missing, probably (more or less) as long as the carapace and overreaching scaphocerite; dorsal border slightly concave, with 13 small articulated spines distributed on proximal half, similar in size, all anterior to the post-orbital margin; distal half unarmed; lower border with seven close, acute teeth; lateral carina well developed, covering bases of eyestalks. Antennal and branchiostegal spines present, the former with a sort of depression behind it which rejoins the inferior orbital angle, the latter feebly developed. Deep hepatic fossa prolonged backwards by a well defined, although not elevated, lateral carina corresponding with the dorsal part of the branchial chamber. Abdomen smooth, pleura of fifth segment ending in acute tooth; sixth somite about 1.9 times as long as fifth; telson broken, almost completely missing. Antennular stylocerite robust, extending almost to anterior margin of second peduncular segment; antennal basicerite with well developed lateral tooth; scaphocerite well developed, lateral border slightly convex, with strong disto-lateral tooth reaching well beyond anterior margin of blade. Eyes small, cylindrical, with well-pigmented globular cornea, cornea diameter only 0.07 of carapace length, stalk diameter equal to cornea diameter.

Due to the firmness of the tegument and in order not to damage this unique specimen, the mouthparts have not been dissected and the branchial formula has not been checked.

Mxp3 extending to distal border of antennal carpocerite. P1 extending to 3/4 of the scaphocerite length; chela without dense zone of setae along dactylar margin, with serrulate cleaning setae proximally on opposite border; carpus 1.6 x chela; dactylus about half length of palm; carpus 1.1 x merus (measured along dorsal line); merus about 1.5 x ischium. Minor P2 elongate, exceeding scaphocerite by length of chela plus last third of carpus; carpus straight (not bowed), 2.2 x chela; dactylus 1/3 of palm; carpus 1.2 x merus (measured along dorsal line); merus 1.6 x ischium (measured along dorsal line). Major P2 exceeding scaphocerite by 5/6 of the chela; ischium 0.7 x merus; carpus a little more than half of chela; chela about 0.75 of carapace length; locking mechanism present, identical to that of other species of the family ( Cleva, 2001: 759, 760). P3, P4 and left P5 missing or incomplete. Right P5 extending to 2/3 of scaphocerite; merus about 1.35 x carpus, and 1.15 x propodus; carpus about 0.85 x propodus; distal third of propodus densely setose; dactylus with nine and 11 ventral spinules on each side of the central line, long and thin, none of them being laterally compressed or flattened as in B. pilosipes , each group arranged in a double row.

Etymology. – It is a pleasure for me to dedicate this new species to Dr. T.Y. Chan.

Remarks. – At first glance, this specimen would be identified as Bathypalaemonetes pilosipes . However, a careful examination reveals marked differences that enable it to be recognized as a new species. In fact this new taxon combines features of the two previous species. Bathypalaemonetes chani , new species, appears to be close to Bathypalaemonetes pilosipes , but it also displays characters of B. brevirostris . Bathypalaemonetes chani differs from B. pilosipes by: higher rostrum (0.14 versus 0.10 of carapace length) and smaller cornea (0.07 versus 0.10-0.09 of carapace length); well marked lateral reliefs on the carapace; shape of fifth abdominal pleuron (ending in sharp tooth, versus rounded); mxp3 with ischiomerus about 3 times longer than penultimate segment (versus 2 times) and with exopodite shorter than ischiomerus (versus much longer), chela of P1 devoid of dense zone of setae along dactylar margin; carpus of the minor P2 straight, not strongly bowed; proportions of articles of major P2: shorter chela (0.75 carapace length, versus only a little shorter, or even longer as in the specimen mentioned above), carpus much longer; dactylus with well defined tubercles; proportions of the P5 articles: carpus shorter than propodus, versus longer than the propodus, and dactyl with a different kind of spinulation.

Bathypalaemonetes chani differs from B. brevirostris in the following points: higher rostrum (0.14 versus 0.10-0.11 of carapace length), with lateral carina less projecting and with borders not sharp, smaller cornea (0.07 versus 0.10 of carapace length); well marked lateral reliefs on the carapace;mxp3 with ischiomerus about 3 times longer than penultimate segment (versus 2 times), exopodite shorter than ischiomerus, ultimate segment not as densely setose; chela of P1 not densely setose along dactylar margin; chela of minor P2 much longer and not bowed; proportions of the articles of major P2 very different: chela much shorter (propodus = 0.75 x carapace length, versus 1.10 to 1.25), carpus much longer; dactylus of fifth pereiopod with a different type of spinulation.

Coloration. – No peculiar pattern ( Fig. 6h ); cephalothorax orange- to red-brownish; abdomen and pleopods pinkishorange; antennal flagella whitish; rostrum, antennules, scaphocerites, pereiopods, sixth abdominal somite and caudal fans deep to dark-red.

Distribution. – Taiwan, 690-700 m depth.

Figures

Fig. 4. Bathypalaemonetes chani, new species, female ov. 15 mm, Holotype, TAIWAN 2001, st. CD 132. Scale bar = 5 mm.

Fig. 6. (a) Stylodactylus major Hayashi & Miyake, 1968, male 37 mm, TAIWAN 2001, st. CD136; (b) Stylodactylus libratus Chace, 1983, male 11 mm, Su-Aou fishing Port; (c) Stylodactylus licinus Chace, 1983, female ov. 16 mm, TAIWAN 2001, st. CD132; (d) Stylodactylus tokarensis Zarenkov,1968, male 8.5 mm, TAIWAN 2001, st. CP115; (e) Bathypalaemonella hayashii Komai, 1995, female 12.5 mm, TAIWAN 2001, st. CP139; (f) Bathypalaemonetes brevirostris (Bruce, 1986), 8.5 mm, TAIWAN 2000, st. CP58; (g) Bathypalaemonetes pilosipes (Bruce, 1986), female 10.5 mm, TAIWAN 2001, st. CD139; (h) Bathypalaemonetes chani, new species, female ov.15 mm, holotype, TAIWAN 2001, st. CD132.