Eualus gracilirostris (Stimpson, 1860)

Xu, Peng & Li, Xin-Zheng, 2015, Report on the Hippolytidae Bate (sensu lato) from China seas, Zoological Systematics 40 (2), pp. 107-165 : 135-137

Eualus gracilirostris (Stimpson, 1860) ( Figs 16–17 )

Hippolyte gracilirostris Stimpson, 1860: 103 . Type locality: Hakodadi.

Spirontocaris gracilirostris Balss, 1914: 44 ; Yokoya, 1933: 26; Urita, 1942: 27.

Eualus gracilirostris Holthuis, 1947: 11 ; Miyake & Hayashi, 1967: 255, fig. 4.

Material examined. MBM109868 , 1 ♀ (cl 4.51 mm), 1958-5-4 , YP2, 49.2 m, mud and gravel, BT; MBM109869 , 1 ♂ (cl 2.33 mm), Huiquan cape, 1981-2-18, coll. Xian-Qiu Ren ; MBM109870 , 1 ♀ (cl 3.95 mm), Hebei, Qinhuang Island, Shanhaiguan , 1974-9-8, coll. Mu Chen ; MBM109871 , 4 ♂ (cl 2.18-2.63 mm) , 3 ♀ (cl 3.11-3.34 mm), Shandong, Qingdao, Daheilan , 1963-11-17, coll. Zhen-Gang Fan & Jie-Shan Xu ; MBM109872 , 11 ♂ (cl 2.14–3.31 mm), 2 ovig . ♀ (cl 3.65, 3.92 mm), Kaifeng; MBM109873 , 1 ♂ (cl 1.47 mm), Shandong, Qingdao, Daheilan , 1964-8-25, coll. Zhen-Gang Fan & Jie-Shan Xu ; MBM109874 , 8 ♂ (cl 2.63–3.49 mm) , 1 ♀ (cl 4.22 mm), Shandong, Weihai, Zhu Island , 1953-11-5 ; MBM109875 , 6 ♂ (cl 2.32–3.29 mm) , 11 ♀ (cl 3.58–4.43 mm), Shandong, Qingdao, Daheilan , 1964-2-28, coll. Zhen-Gang Fan & Jie-Shan Xu ; MBM109877 , 7 ♂ (cl 2.23–3.88 mm) , 9 ♀ (cl 3.72–4.39 mm), Shandong, Qingdao, Daheilan , 1957-2-14, coll. Feng-Xuan Zhang & En-Ze Yang ; MBM109880 , 3 ♀ (cl 4.03–4.57 mm), 1954-6-20 ; MBM109882 , 7 ♂ (cl 2.21–2.80 mm) , 1 ♀ (cl 3.32 mm), 1 ovig. ♀ (cl 3.17 mm), Shangdong, Yantai, Kongtong Island , 1957-7-2, coll. Jie-Shan Xu ; MBM109886 , 6 ♂ (cl 2.96–3.80 mm), Yellow Sea , 1958-3-24 ; MBM109888 , 6 ♂ (cl 2.16–2.59 mm), Shandong, Qingdao, Daheilan , 1963-9-19 ; MBM109889 , 4 ♂ (cl 3.19–3.36 mm) , 3 ♀ (cl 3.57–3.91 mm), Shandong, Longkou, Furong Island , 1956-2-12 ; MBM109930 , 3 ♀ (cl 4.31–4.46 mm), 1 ovig . ♀ (cl 4.07 mm), Shandong, Qingdao, west coast of Tuandao , 1951-3-9 ; MBM109892 , 9 ♀ (cl 3.85–4.67 mm), Shandong, Qingdao, Mai Island , 1951-12-22 ;

© Zoological Systematics, 40 (2): 107–165 MBM109895 , 3 ♀ (cl 4.30–4.61 mm), Shandong, Qingdao Aquarium , 1955-2-10 ; MBM109896 , 1 ♂ (cl 3.40 mm), Huangdao , 1955-10-31, coll. Jie-Shan Xu ; MBM109897 , 4 ♂ (cl 2.00– 2.36 mm), 1 ♀ (cl 2.46 mm), Shandong, Qingdao, Daheilan , 1963-10-21, coll. Zhen-Gang Fan, Jie-Shan Xu, Xiu-Bin Fang & Mu Chen ; MBM109898 , 3 ovig. ♀ (cl 2.52–2.79 mm), Shandong, Yantai, Dongshan , 1957-6-27, coll. Jie-Shan Xu ; MBM109899 , 1 ♂ (cl 3.36 mm), Shandong, Qingdao, Daheilan , 1963-6-21, coll. Zhen-Gang Fan, Jie-Shan Xu, Xiu-Bin Fang & Mu Chen ; MBM109900 , 3 ♂ (cl 2.87–2.99 mm), 7 ovig. ♀ (cl 3.46–4.29 mm), Shandong, Qingdao, Daheilan , 1963-5-21, coll. Bin Fan ; MBM109901 , 1 ♀ (cl 4.41mm), 3 ovig. ♀ (cl 3.69–4.26 mm), Shandong, Qingdao, Shilaoren , 1956-4-10, coll. Zhen-Gang Fan & Yong-Liang Wang ; MBM109903 , 1 ♂ (cl 3.44 mm), Shandong, Qingdao, Shilaoren , 1957-1-4, coll. Jie-Shan Xu ; MBM109904 , 1 ♀ (cl 4.38mm), Shandong, Qingdao, Guizhou Road , 1955-3-19 ; MBM109905 , 5 ♂ (cl 2.34–2.87 mm), 2 ♀ (cl 2.95, 3.21 mm), Shandong, Qingdao, Taiping Cape, 1981-11-14 ; MBM129718 , 17 ♂ (cl 2.19–3.82 mm), 3 ♀ (cl 3.59–4.19 mm), Shandong, Qingdao, Mai Island , 1954-11-13 .

Description. Rostrum slender, dorsal margin with 6 teeth, of which posterior one situated on carapace; ventral margin armed with 2–4 subterminal teeth. Rostrum reaching distal margin of antennular peduncle in female, not reaching distal margin of second segment of antennular peduncle in male. Carapace longer than rostrum, with antennal tooth moderately strong; pterygostomial tooth present or not.

Pleurae of fourth and fifth abdominal somites each with small posteroventral tooth; telson about 1.5 times longer than sixth abdominal somite; dorsal surface with 4 pairs of dorsolateral spines. Apex of telson acutely pointed, with 2 pairs of spines and 1 mesial pair of stiff setulose setae.

Eye moderate; stalk longer than cornea.

Antennular peduncle reaching midpoint of antennal scale; three segments of antennular peduncle each with small spine on its distal margin; stylocerite of female specimen reaching midpoint of second segment of antennal peduncle, but that of male rather shorter, reaching almost to distal margin of first segment of antennular peduncle. Antennal scale broad, 2 times as long as wide. Third maxilliped exceeding antennal scale by 1/4 length of ultimate segment in female, reaching tip of antennal scale in male; with both of exopod and epipod.

First pereopod short and robust, with epipod; reaching distal margin of antennular peduncle. Second pereopod slender, with epipod; carpus subdivided into 7 articles. Following 3 pereopods subequal in features and without epipods. Merus of

© Zoological Systematics, 40 (2): 107–165 third pereopod armed with 2–5 distolateral spines; dactylus of third pereopod armed with 4 or 5 spinules in female and 6 or 7 in male.

Appendix interna of female expanded in distal part and bearing many coupling hooks; appendix masculine of male large and short, being half length of appendix interna with truncated tip which bearing eight long hairs.

Coloration in life. Body pale brown and yellowish green. Carapace with some red brown transverse lines. Abdominal somites with one red brown transverse line on first somite and two similar lines on both second and third somites. Tail fan with broad dark brown transverse band. Antennal flagellum light orange. Third maxilliped and following five pereopods with some greenish-brown bands. Eggs dull green.

Distribution. Northern China waters; Sea of Japan; often in rocky intertidal beach; 0– 60 m.

Figures

Fig. 16. Eualus gracilirostris (Stimpson, 1860). A. Carapace, lateral view; B. Abdominal pleurae, lateral view; C. Antennular peduncle, dorsal view; D. Antennal scale, dorsal view; E. Telson, dorsal view; F. Apex of telson, dorsal view; G. Endopod of first pleopod of male, ventral view; H. Endopod of second pleopod of male, ventral view. Scale bars=1mm.

Fig. 17. Eualus gracilirostris (Stimpson, 1860). A. Third maxilliped,lateral view; B. First pereopod, lateral view; C. Second pereopod, lateral view; D. Third pereopod, lateral view; E. Dactylus of third pereopod, lateral view. Scale bars=1mm.