Eualus heterodactylus Xu & Li, 2014

Xu, Peng & Li, Xin-Zheng, 2015, Report on the Hippolytidae Bate (sensu lato) from China seas, Zoological Systematics 40 (2), pp. 107-165 : 137-141

Eualus heterodactylus Xu & Li, 2014 ( Figs 18–20 )

Eualus heterodactylus Xu & Li, 2014a: 1 339. Type locality: Yellow Sea.

Material examined. MBM109929 , 1 ♂ (cl 2.20 mm), Chinese coastal water, Yellow Sea, 1957-7-26, st. Y207, 47.5m, sandy mud, BT, no. VIII 1B-17, coll. Rui-Yu Liu ; MBM109927 , 11 ovig. ♀ (cl 1.86–3.17 mm), 10 ♂ (cl 1.61–2.95 mm), Chinese coastal water, Yellow Sea, 1957-7-26, st. Y108, 47.5 m, sand, no . VI5 B-28, coll. Rui-Yu Liu ; MBM109933 , 1 ovig. ♀ (cl 2.90 mm), Chinese coastal water, Yellow Sea, 1957-10-2, st. Y205, 51.1 m, sandy mud and crushed shells, BT, no. VIX3B-24, coll. Rui-Yu Liu ; MBM109928 , 3 ovig. ♀ (cl 3.00– 3.09 mm), Chinese coastal water, Yellow Sea, 1957-7-12, st. P401, 52 m, sandy mud, BT, no. VII1B-34, coll. Rui-Yu Liu .

Description. Male. Integument moderately thin, smooth. Rostrum 0.7–0.8 length of carapace, nearly straight, slightly descending, reaching cornea and not exceeding basal segment of antennular peduncle; dorsal margin with 5–7 teeth, posterior-most one on carapace posterior to orbitalmargin; distal quarter unarmed; ventral margin armedwith one or two small sub-terminal tooth; lateral carina notconspicuous. Carapace with well-developedantennal tooth and minute pterygostomian tooth; anterolateral margin between antennal and pterygostomian tooth sinuous.

Abdomen rounded dorsally. Pleurae of fourth and fifth abdominal somites each with smallposteroventral tooth. Sixth somite 1.7 times as long as fifth. Telson about 1.4 times as long as sixth abdominal somite; dorsal surface with four pairs of dorsolateral spines and three pairs of terminal spines, lateral pair similar to dorsolateral series; posterior margin of telson terminates in small acute tooth.

Eye subpyriform; cornea with indistinct ocellar spot, shorter than stalk.

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Antennular peduncle reaching distal 0.2 of antennal scale. Basal segment reaching nearly to midlength of antennal scale, with prominent distolateral tooth and strong subdistal, ventromesial tooth; stylocerite 0.7–0.8 length of basal segment (exclusive of dorsolateral tooth), terminating in acute point. Distal two segments combined are 0.7 times length of basal segment, each with distinct spiniform distal tooth. Outer flagellum with 10–12 thickened segments, slightly shorter than length of carapace. Inner flagellum slender, elongate, about 1.4 times length of outer flagellum, with 28–33 segments.

Antennal peduncle with basicerite bearing strong ventrolateral distal tooth, distodorsalangle bluntly produced. Carpocerite reaching midlength of antennal scale. Antennal scale subequalin length to carapace, 3.2 times as long as wide. Lateral margin faintly concave, with distolateral tooth slightly shorter or just reaching rounded distal margin of blade.

Mouthparts typical of genus. Mandible with two-segmented palp; incisor processs lender, with series of five subequal, tiny, distal teeth; molar process stout.

Third maxilliped moderately long and slender, reaching beyond or overreaching antennal scale; ultimate segment 2.9 times as long as penultimate segment, with 4–6 corneous spines distally; antepenultimate segment subequal in length to distal two segments combined, distoventral margin with small spine. Exopod exceeds middle of antepenultimate segment; epipod present.

First to third pereopods with strap-like, terminally hooked epipods.

First pereopod moderately stout, falling short of distal margin of antennal scale. Chela about 1.8 times as long as carpus, 4.1 times as wide; dactylus with bifid tip, slightly less than half length of palm; palm subcylindrical, 2.6 times as long as wide, fixed finger terminating in single corneous claw. Carpus slightly more than twice as long as wide. Merus 4.2

© Zoological Systematics, 40 (2): 107–165 times as long as wide.

Second pereopod overreaching antennal scale by 0.4 length of carpus; carpus with seven articles, third proximal article longest. Merus tentimes as long as wide.

Third pereopod moderately long and slender, overreaching antennal scale by about half of propodus; dactylus 0.2–0.3 times as long as propodus, about 2.5 times as long as high, armed with six accessory spines along entire length of stair-like flexor margin (excluding terminal claw), each spine with strongly protruding base. Propodus 11 times as long as wide; flexor margin with about 40 spinules in two rows, spinules increasing in size distally. Carpus about half length of propodus, 4.2–6.3 times as long as wide. Merus 5.6 times as long as wide, with 2–4 lateral spines distally. Ischium about 0.3 length of merus, unarmed, not widened distally.

Fourth and fifth pereopod similar to third pereopod, former overreaching antennal scaleby 0.4 length of propodus, merus with 2–3 lateral spines distally; latter with merus armed with one or two distolateral spines.

First pleopod with endopod elongate subtriangular, with some setae on lateral margin; appendix interna terminal, elongate, about half length of enopod. Second pleopod with appendix masculina moderately stout, about 3.0 times as long as wide, about 0.6 length of appendix interna and bearing seven long stiff setae.

Female. Body stout. Rostrum exceeding basal segment of antennularpeduncle, not reaching distal margin of third segment of antennular peduncle; ventral margin armed with two small subterminal teeth. Stylocerite reaching distal margin of first segment of antennular peduncle. Dactylus of ambulatory pereopods biunguiculate, armed with three or four accessory spines along entire length of flexor margin, bases not protruded. Merus of third and fourth pereopods armed with © Zoological Systematics, 40 (2): 107–165

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

2–4 distolateral spines. Merus of fifth pereopod armed with one distolateral spine. Dorsal surface of telson with 4 or 5 pairs of dorsolateral spines.

Coloration in life. Unknown.

Distribution. Only known from type locality Yellow Sea at depths of 30– 50 m.

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Figures

Fig. 18. Eualus heterodactylus Xu & Li, 2014 (After Xu & Li, 2014a). A. Male, whole body, lateral view; B. Male, rostrum, lateral view; C. Female, whole body, lateral view. Scale bars =1mm.

Fig. 19. Eualus heterodactylus Xu & Li, 2014, male (After Xu & Li, 2014a). A. Anterior part of carapace and cephalic appendages, dorsal view (marginal setae of antennal scale omitted); B. Telson and uropod, dorsal view (marginal setae omitted). Scale bars = 1 mm.

Fig. 20. Eualus heterodactylus Xu & Li, 2014 (After Xu & Li, 2014a). A–N. Male. A. Left mandible, external view; B. Left maxillule, external view; C. Left maxilla, external view; D. Left first maxilliped, external view; E. Left second maxilliped, external view; F. Right third maxilliped,lateral view; G. First pereopod, lateral view; H. Second pereopod,lateral view; I. Third pereopod, lateral view; J. Fourth pereopod,lateral view; K. Fifth pereopod, lateral view; L. Dactylus of thirdpereopod, lateral view; M. Endopod of first pleopod, ventral view (setae partially omitted); N. Endopod of second pleopod, ventralview (setae partially omitted). O. Female, dactylus of third pereopod, lateral view. Scale bars=1mm.