Caridina spinicrus Cai & Ng, 2018, sp. nov.
Creators: name: Cai, Yixiong
name: Ng, Peter Kee Lin
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Atyidae
Caridina
Caridina spinicrus

description: Caridina spinicrus sp. nov.   
(Figs. 7-9)  
urn:lsid:zoobank.org:act: EF868C18-D01C-4920-A9C4- 51DFACB8D42C  
 Material examined: Holotype: male, cl 5.5 mm, IZCAS DE 5031, artificial pond inside Goulou Cave in Beiliu County, Guangxi Province, southern China, coll. Y. Cai et al., 30 Oct 1993; Paratypes: 2 males, cl 5.5-6.0 mm, ZRC 2018.0482, same data as holotype.   
 Description: Rostrum (Fig. 7A) straight, reaching anterior half of second segment of antennular peduncle, dorsally with 17 teeth, of which 7 on carapace behind posterior margin of orbital margin, occupying 0.14 carapace length, armed ventrally with only 1 small tooth. Antennal spine sharp, completely fused with suborbital angle. Pterygostomian angle rounded.   
Telson (Fig. 9B) with posteromedian projection, posterior margin rounded, lateral pair of spines longer than intermediate pairs, sub-lateral pair being shortest.  
Eyes well developed (Fig. 7A). Antennular peduncle 0.50 times as long as carapace. Stylocerite reaching 0.7 basal segment length of antennular peduncle. Scaphocerite (Fig. 8H) 3.0 times as long as wide, outer margin slightly concave.  
Mouthparts as figured. Mandible (Fig. 7B) with blunt teeth at extremity of incisor process. Maxillula (Fig. 7C) with simple palp, lower lacinia broadly rounded, upper lacinia broadly elongated, inner edge straight, with setae and teeth. Maxilla (Fig. 7D) with slender palp, upper endite subdivided, scaphognathite tapering with numerous long setae posteriorly. Palp of first maxilliped (Fig. 7E) ending as triangular projection. Endopod of second maxilliped (Fig. 7E) with fused dactylus and propodal segments. Third maxilliped (Fig. 7G) reaching beyond distal end of scaphocerite, ending in single terminal claw; exopod reaching 0.5 times penultimate segment length, ultimate segment as long as pentultimate segment. Epipods on first 4 pereiopods.  
First pereiopod (Fig. 8A, B) reaching end of basal segment of antennular peduncle, merus 2.7 times as long as broad; carpus concave anteriorly, 1.7 times as long as high, chela 2.5 times as long as broad, fingers 1.3 times as long as palm. Second pereiopod (Fig. 8C) reaching to end of antennular peduncle, carpus 5.2 times as long as high, chela slightly shorter than carpus, 2.7 times as long as broad, fingers 1.7 times as long as palm. Third pereiopod (Fig. 8D) long, stout, reaching beyond distal end of scaphocerite. Merus 4.0 times as long as broad; carpus 2.4 times as long as broad, ventral surface armed with a row of 16 closely packed strong spines. Propodus strongly curved inwards, 9.0 times as long as broad, 4.0 times as long as dactylus (claw included), ventral surface armed with row of 23 strong spines, similar to those of at carpus, but more widely lined anteriorly; dactylus terminating as a claw, with 5 accessory spines on flexor margin. Fourth pereiopod (Fig. 9C, D, E) reaching to distal end of antennular peduncle, similar to third pereiopod in form, with strong spines on ventral surfaces of carpus and propodus. Fifth pereiopod (Fig. 9F, G)  
© 2018 Academia Sinica, Taiwan  
(B)  
© 2018 Academia Sinica, Taiwan  
© 2018 Academia Sinica, Taiwan  
© 2018 Academia Sinica, Taiwan  
reaching distal end of antennular peduncle; merus 4.0 times as long as broad; carpus 4.0 times as long as broad; propodus slightly curved inwards, 10 times as long as broad, 3.8 times as long as dactylus; dactylus with 50 spinules on flexor margin.  
Endopod of male first pleopod (Fig. 8E) reaching to 0.67 endopod length, subrectangular, distal end rounded, inner margin slightly curved backwards, 3.0 times as long as wide; appendix interna situated at posterior 0.2 endopod length, extending to end of endopod. Appendix masculina of male second pleopod (Fig. 8F, G) narrowing down distally, with 2 rows of spines at inner surface, reaching to 0.75 of endopod length; appendix interna of male second pleopod small, reaching to 0.4 appendix masculina length.  
Uropodal diaeresis (Fig. 7H) with 13 spinules.  
 Habitat: Caridina spinicrus sp. nov. was collected together with C. beiliu sp. nov. from an artificial concrete pond inside Goulou Cave in Beiliu County. The water comes from a subterranean river.   
 Etymology: Caridina spinicrus is named for its distinctive spiny third and fourth pereiopods, from the Latin for spiny and legs (crura). The name is used as a noun in apposition.   
 Remarks: With regard to the spiny third and fourth pereiopods, only one species, Caridina crurispinata Gurney, 1984, described from a cave in Madagascar, shares such features. Compared with C. crurispinata, the spines on the third and fourth pereiopods in C. spinicrus sp. nov. are more prominent (Fig. 8D; Fig. 9C, D, E) (vs. less prominent; cf. Gurney, 1984: fig. 6C). Apart from this, C. spinicrus can be distinguished from C. crurispinata by the straight rostrum which reaches to the anterior half of the second segment of antennular peduncle (Fig. 7A) (vs. gradually curving upwards and reaching beyond the antennal scale; cf. Gurney, 1984: fig. 4B); and the presence of an appendix interna on the endopod of the male first pleopod (Fig. 8E) (vs. absent; cf. Gurney, 1984: fig. 7B).   
 Compared with other Chinese species, C. spinicrus also superficially resembles the sympatric C. beiliu sp. nov. However, C. spinicrus can easily be separated by the rostrum not reaching beyond the end of the second segment of the antennular peduncle (Fig. 7A) (vs. beyond the end of the second segment of the antennular peduncle; Fig. 10A); the more slender first pereiopod having the dactylus 2.5 times as long as broad (Fig. 8A, B) (vs. 1.5 times; Fig. 11A); and the male first pleopod having an appendix interna that reaches to the distal end of the endopod (Fig. 8E) (vs. distinctly reaching beyond; Fig. 12 D-F).   
 Distribution: Guangxi Province (Goulou Cave), China.
description: Published as part of Cai, Yixiong & Ng, Peter Kee Lin, 2018, Freshwater Shrimps from Karst Caves of Southern China, with Descriptions of Seven New Species and the Identity of Typhlocaridina linyunensis Li and Luo, 2001 (Crustacea: Decapoda: Caridea), pp. 1-33 in Zoological Studies 57 (27) on pages 9-13, DOI: 10.6620/ZS.2018.57-27, http://zenodo.org/record/13314991