Eualus spathulirostris (Yokoya, 1933)

Xu, Peng & Li, Xin-Zheng, 2015, Report on the Hippolytidae Bate (sensu lato) from China seas, Zoological Systematics 40 (2), pp. 107-165 : 143-145

Eualus spathulirostris (Yokoya, 1933) ( Fig. 23 )

Spirontocaris spathulirostris Yokoya, 1933: 28 ; Holthuis, 1947: 23. Type locality: Tsugaru Strait.

Eualus spathulirostris Miyake & Hayashi, 1968: 367 .

Material examined. MBM109934 , 11 ♂ (cl 4.21–5.36 mm) , 5 ♀ (cl 3.61–5.31 mm), 10 ovig. ♀ (cl 4.62–5.97 mm), Yellow Sea , 1958-5-4, 49.2 m, mud, gravel and shell fragment, BT ; MBM109936 , 1 ♂ (cl 2.60 mm), Yellow Sea , 1992-9-13, 77 m, fine sand, AT ; MBM109937 , 6 ♂ (cl 3.97–4.52 mm) , 5 ♀ (cl 4.01-5.45mm), 1957-3-14; MBM109940 , 2 ♂ (cl 2.69, 3.24 mm), 1 ovig . ♀ (cl 4.70 mm), Yellow Sea , 1958-4-16, 52.8 m, mud, BT ; MBM109942 , 2 ♀ (cl 4.03, 4.29 mm), Yellow Sea , 1957-11-14, 55 m, BT, coll. Rui-Yu Liu ; MBM109943 , 3 ♂ (cl 3.68–4.52 mm) , 5 ♀ (cl 4.07–5.66 mm), 1 ovig. ♀ (cl 4.24 mm), Northern Yellow Sea , 1959-1-22, sandy mud, 55 m, BT, coll. Yu-Heng Cui ; MBM109945 , 2 ♂ (cl 3.28, 3.80 mm), 3 ovig . ♀ (cl 3.45–3.91 mm), Yellow Sea , 1962-3-5, 54 m, sandy mud, AT, coll. Feng-Shan Xu ; MBM109952 , 8 ♂ (cl 3.58–4.32 mm) , 4 ♀ (cl 4.23–4.75mm), Yellow Sea , 1957-11-15, 51 m, fine sand, BT, coll. Rui-Yu Liu ; MBM109954 , 1 ♀ (cl 5.04 mm), East China Sea, 1976-7-22, 70 m, fine sand, AT, coll. Zhi-Can Tang ; MBM109955 , 2 ♂ (cl 4.13, 5.33 mm), Yellow Sea , 1992-9-14, mud, 26m, coll. Feng-Shan Xu ; MBM109956 , 3 ♂ (cl 3.82–4.41 mm), Yellow Sea , 1958-4-15, 60.4 m, mud, BT ; MBM109958 , 5 ♂ (cl 3.69–4.42 mm), Yellow Sea , 1957-11-15, 54 m, mud, BT, coll. Rui-Yu Liu ; MBM109959 , 4 ♂ (cl 3.87–5.30 mm), 3 ovig . ♀ (cl 4.18–4.70 mm), 1958-6-21; MBM109961 , 4 ♂ (cl

© Zoological Systematics, 40 (2): 107–165 4.34–5.46 mm), 10 ovig. ♀ (cl 5.23–6.59 mm), Yellow Sea, 1958-7-9; MBM109962 , 1 ♀ (cl 5.29 mm), 3 ovig. ♀ (cl 4.02-4.27 mm), Yellow Sea, 1957-7-29, 52 m mud, BT, coll. Rui-Yu Liu ; MBM109963 , 11 ovig. ♀ (cl 5.63–6.98 mm), Yellow Sea , 1992-5-21, 61 m, fine sand, AT, coll. Feng-Shan Xu ; MBM109964 , 2 ♂ (cl 3.10, 3.78 mm), 3 ♀ (cl 4.17–4.53 mm), Yellow Sea, 1957-11-14, 57 m, mud, BT, coll. Rui-Yu Liu ; MBM109965 , 4 ♂ (cl 2.56–4.13 mm), Yellow Sea , 1957-11-16, 46 m, mud and sand, BT, coll. Rui-Yu Liu ; MBM109966 , 6 ♂ (cl 3.31–4.65 mm), 1957-8-4, 26 m, BT, coll. Rui-Yu Liu ; MBM109967 , 1 ♂ (cl 2.57 mm), 1 ovig. ♀ (cl 3.91 mm), Yellow Sea, 1957-7-28, 47.5 m, BT, coll. Rui-Yu Liu ; MBM109969 , 2 ovig. ♀ (cl 3.59, 4.42 mm), Yellow Sea , 1992-5-23, 47.5 m, sandy mud, AT, coll. Feng-Shan Xu ; MBM109970 , 3 ♀ (cl 4.88–5.17 mm), Yellow Sea , 1958-7-9, 55.6 m, mud, AT ; MBM109973 , 1 ovig. ♀ (cl 4.92 mm), Yellow Sea , 1992-9-12, 48 m, mud, AT, coll. Feng-Shan Xu ; MBM109979 , 3 ♂ (cl 3.99–4.47 mm), 2 ♀ (cl 4.22, 4.54 mm), 2 ovig. ♀ (cl 4.71, 4.76 mm), Yellow Sea, 1957-7-26, 47.5 m, sandy mud, BT, coll. Rui-Yu Liu ; MBM109981 , 3 ♂ (cl 5.16–5.31 mm), Yellow Sea , 1992-9-12, 72 m, mud, AT, coll. Feng-Shan Xu ; MBM109982 , 5 ♂ (cl 3.86–4.97 mm), 4 ♀ (cl 4.56–4.78 mm), 6 ovig. ♀ (cl 4.38–4.61 mm), Yellow Sea, 1957-10-28, 50 m, coll. Rui-Yu Liu ; MBM109983 , 2 ovig. ♀ (cl 5.09, 5.34 mm), Yellow Sea , 1992-5-23, 21 m, mud, AT, coll. Rui-Yu Liu ; MBM057600 , 1 ♂ (cl 2.83 mm), Yellow Sea , 1959-7-21, 54 m, brown mud, BT, coll. Gong-Yi Hu ; MBM057713 , 1 ♂ (cl 4.25 mm), Yellow Sea , 1959-10-29, 55.8m, brown mud, BT, coll. Gong-Yi Hu .

Description. Carapace anteriorly with high keel which is thin and continuous with proximal part of rostrum. There are 9 to 12 small teeth on keel. Rostrum reaching distal end of antennular peduncle. No tooth on distal half of dorsal margin. Ventral margin somewhat dilated distally, bearing 1 or 2 teeth on dilated portion. Antennal spine well-developed, pterygostomian tooth small but conspicuous.

Abdomen rounded dorsally. Pleurae of first four somites broadly rounded. Pleura of fifth somite with sharp posteroventral tooth. Sixth somite twice as long as fifth. Telson slightly longer than sixth abdominal somite, with 3 pairs of dorsolateral spines and 3 pairs of terminal spines.

Eye large and globular; cornea much broader than stalk.

Basal segment of antennular peduncle longer than distal two segments combined. Stylocerite reaching distal end of basal segment. Second segment rather long, twice as long as third, with marginal spine on outer side. Third segment with small marginal spine on top of segment. Upper antennular flagellum thickened and setose in proximal 11–14 segments. Antennal scale slender, about 4.5 times as long as wide; lateral margin straight, ending in sharp spine. Mouthparts typical of genus. Mandible with two-segmented palp; incisor process slender, with series of 4 subequal, tiny, distal teeth; molar process stout.

Third maxilliped reaching distal margin of antennal scale; ultimatesegment almost 3 times as long as penultimate; antepenultimate segment rather long, about 1.5 times as long as ultimate; exopod short, reaching proximal 1/4 or 1/3 of antepenultimate segment.

© Zoological Systematics, 40 (2): 107–165

First pereopod reaching distal end of antennular peduncle; merus about 1.5 times as long as carpus; carpus slender, subequal or slightly shorter than narrow chela. Second pereopod slender, exceeding antennal scale by length of chela; merus andischium subequal in length; carpus with 7 articles, third proximal article longest. Third pereopod moderately long and slender; merus 2.5 times as long as carpus, with 6 to 8 lateral spines along outer surface; propodus twice as long as carpus, with 9 spines on flexor margin; extensor margin with a few plumose hairs.

Dactylus like strongly curved nail, about more than half of propodus, without any spine on flexor margin. Fourth pereopod overreaching antennal scale by dactylus; merus armed with 6 or 7 spines on outer surface; dactylus slender, about half of propodus. Fifth pereopod reaching distal margin of antennal scale; with 6 or 7 spines on outer surface of merus.

Endopod of first pleopod of male very small, bearing appendix interna with a few retinacula placed near tip of endopod. Appendix masculina of second pleopod furnished with several strong setae, being 1/3 as long as appendix interna. Appendix interna of female armed with many retinacula on distal half.

Distribution. Yellow Sea, East China Sea; northern Japanese waters; 20– 80 m.

Figures

Fig. 23. Eualus spathulirostris (Yokoya, 1933). A. Carapace, lateral view; B. Abdominal pleurae, lateral view; C. Third pereopod, lateral view. Scale bars=1mm.