Heptacarpus commensalis Hayashi, 1979

Xu, Peng & Li, Xin-Zheng, 2015, Report on the Hippolytidae Bate (sensu lato) from China seas, Zoological Systematics 40 (2), pp. 107-165 : 148

Heptacarpus commensalis Hayashi, 1979 ( Fig. 25 )

Heptacarpus commensalis Hayashi, 1979: 14 . Type locality: Shirahama.

Material examined. MBM129660 , 1 ♀ (cl 2.93 mm), Shandong, Qingdao , Jiaozhou Bay, 1964-8-4, st. K033, 45m, sand and shell fragment, AT, no. M133A-7 ; MBM129663 , 7 ♂ (cl 1.73–2.38 mm), 13 ovig . ♀ (cl 2.65–3.86 mm), 10 ♀ (cl 2.41–3.73 mm), Shandong, Qingdao, Shazikou , 1955-7-9, no. 55-01015 ; MBM129683 , 1 ♂ (cl 2.16 mm), Shandong, Qingdao, Shazikou , 1952-3-18, no. 57-210, coll. En-Ze Yang .

Description. Small shrimps about 3.5 mm rostral length in ovigerous females and males slightly smaller than females. Rostrum straight, as long as or slightly longer than carapace, with 5–6 teeth on dorsal margin, of which posterior two teeth present on carapace and two teeth on ventral margin near apex. Carapace smooth, with well-developed antennal and pterygostomial spines in females but with well-developed antennal spine and pterygostomial angle armed or unarmed in males. Abdomen smooth, third somite not strongly geniculate. Pleurae of fourth and fifth somites ending in sharp tooth. Telson 1.2–1.3 times as long as sixth somite with 4 pairs of dorsal spines; posterior margin pointed at middle, armed with 3 pairs of spines. Eye comparatively large, with distinct ocellus.

Antennular peduncle reaching nearly torostral apex, each segment with small marginal spine. Stylocerite reaching distal marginof first segment. Antennal scale broad, exceeding beyond rostrum by distal half. Outer terminal spine exceeding lamellar part. Epipods on third maxilliped and first three pereopods. Third maxilliped reaching beyond antennal scale by distal half of ultimate segment. First pereopod robust, reaching distal margin of antennal scale, merus without subterminal spine. Second pereopod slender, exceeding antennal scale by chela and distal half of carpus; carpus subdivided into 7 articles.

Third pereopod overreaching antennal scale by dactylus and half propodus. Dactylus short with 6 teeth on flexor margin, propodus slender, about 4 times as long as dactylus, with 11 teeth on flexor margin. Merus with 3 or 4 teeth on distal outer surface. Following two pereopods resemble third one in structure. Fourth pereopod overreaching antennal scale by dactylus. Fifth pereopod just reaching distal margin of antennal scale. Dactylus and propodus of these two pereopods slightly shorter than those of third pereopod but with similar structure, but with tuft of hairs on outer distal end of fifth propodus. Merus of fourth pereopod with 2 or 3 spines on distal outer surface near distal articulation, that of fifth pereopod with single subterminal spine.

Endopod of first pleopod with some retinaculae near apex and with about 10 shortplumose setae on inner margin. Appendix masculina of second endopod in males very short, with about 10 setae on top.

Distribution. Chinese coast of Yellow Sea; northern gulf of Japan; 10– 70 m.

Remarks. This species was not previously recorded from the China seas.

Figures

Fig. 25. Heptacarpus commensalis Hayashi, 1979. A. Carapace, lateral view; B. Abdominal pleurae, lateral view; C. Telson, dorsal view; D. Third maxilliped, lateral view; E. First pereopod, lateral view; F. Second pereopod, lateral view; G. Third pereopod, lateral view; H. Second endopod in male, lateral view. Scale bars=1mm.