Thinora leptochelus, Xu & Li, 2015

Xu, Peng & Li, Xin-Zheng, 2015, Report on the Hippolytidae Bate (sensu lato) from China seas, Zoological Systematics 40 (2), pp. 107-165 : 121-122

Thinora leptochelus sp. nov. ( Fig. 7 )

Material examined. Holotype, ovig. ♀, MBM136585 , cl 2.05mm, coral reef, Xisha Islands , 1957-4-29.

Description. Rostrum much shorter than carapace; dorsal and ventral margins each with only one tooth. Carapace with sharp supraorbital tooth and antennal tooth, without pterygostomian tooth. Pleurae of fourth and fifth abdominal somites each with small posteroventral tooth; sixth somite 1.4 times as long as fifth somite. Telson 1.5 times as long as

© Zoological Systematics, 40 (2): 107–165 sixth somite; dorsal surface with 3 pairs of dorsolateral spines and posterior margin with 2 pairs of spines and 1 mesial pair of stiff setulose setae.

Eye pyriform, cornea with distinct ocellar spot, slightly shorter than stalk. Antennular peduncle reaching midpoint of antennal scale; second segment with acute distolateral spine; third segment of antennular peduncle with subtriangular dorsal scale; stylocerite reaching distal margin of antennular peduncle, armed with little indistinct tooth near proximal end of lateral margin. Antennal scale 2.1 times as long as wide; lateral margin straight, with distolateral tooth reaching rounded distalmargin of blade. Antennal peduncle with basicerite bearing strong ventrolateral distal tooth.

Third maxilliped with exopod; reaching distal margin of antennal scale; ultimate segment with 8 corneous spines distally; antepenultimate segment subequal in length to ultimate segment. First pereopod reaching distal 1/4 of antennal scale; chela slender and cone-shaped; dactylus 0.4 times as long as palm; carpus 0.6 times as long as chela; merus subequal in length to carpus. Second pereopod overreaching distal margin of antennal scale by dactylus; chela small, slender and cone-shaped; dactylus 0.4 times as long as palm; carpus 2.6 times as long as chela; carpus subdivided into 6 articles, of which proximal third one longest; merus about 0.7 times as long as carpus; ischium thicker and shorter than merus. Third pereopod overreaching distal margin of antennal scale by dactylus and 1/4 length of propodus; flexor margin of biunguiculate dactylus with 3 spinules; distal half of flexor margin of propodus with 6–8 spinules; carpus about 0.4 times as long as propodus; merus shorter than propodus, armed with 1 distolateral spine. Fourth and fifth pereopods similar to third pereopod. Fourth pereopod reaching distal margin of antennal scale; merus with 1 distolateral spine. Fifth pereopod overreaching midpoint of antennal scale by dactylus; outer margin of merus unarmed.

Distribution. Xisha Islands, South China Sea.

Etymology. The Greek “ leptos ”, slender, fine, “ chēlē ”, claw, unguis. The specific name indicates the chelae of first and second pereopods being slender and cone-shaped.

Remarks. This new species is described based on only an ovigerous female specimen. We put it in the genus Thinora rather than Thor because it bears only 1 tooth on the dorsal margin of rostrum, and the carapace lacks pterygostomian tooth. The new species can be easily distinguished from the only knwon species of the genus, Thinora maldivensis (Borradaile, 1915) , by the developed supraorbital tooth and the slender and cone-shaped chelae of the first 2 pereopods. Additionally, the unarmed merus of first pereopod in the new species is also different from that of T. maldivensis which has 1 acute distolateral tooth.

Figures

Fig. 7. Thinora leptochelus sp. nov. A. Carapace, lateral view; B. Abdominal pleurae, lateral view; C. Telson, dorsal view; D. Antennule, dorsal view; E. Antennal scale, dorsal view; F. Third maxilliped, lateral view; G. First pereopod, lateral view; H. Second pereopod, lateral view; I. Third pereopod, lateral view. Scale bars=1 mm.