Caridina spinicrus, Cai & Ng, 2018

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), Zoological Studies 57 (27), pp. 1-33 : 9-13

publication ID	https://doi.org/ 10.6620/ZS.2018.57-27
DOI	https://doi.org/10.5281/zenodo.12826764
persistent identifier	https://treatment.plazi.org/id/03998788-FF94-041C-CB3B-FA373CF4FE62
treatment provided by	Felipe
scientific name	Caridina spinicrus
status	sp. nov.

Treatment

Caridina spinicrus View in CoL sp. nov.

( Figs. 7-9 View Fig View Fig View Fig )

urn:lsid:zoobank.org:act:EF868C18-D01C-4920-A9C4-51DFACB8D42C

Material examined: Holotype: male, cl 5.5 mm, IZCAS DE 5031 View Materials , 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 View Fig ) 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 View Fig ) with posteromedian projection, posterior margin rounded, lateral pair of spines longer than intermediate pairs, sub-lateral pair being shortest.

Eyes well developed ( Fig. 7A View Fig ). Antennular peduncle 0.50 times as long as carapace. Stylocerite reaching 0.7 basal segment length of antennular peduncle. Scaphocerite ( Fig. 8H View Fig ) 3.0 times as long as wide, outer margin slightly concave.

Mouthparts as figured. Mandible ( Fig. 7B View Fig ) with blunt teeth at extremity of incisor process. Maxillula ( Fig. 7C View Fig ) with simple palp, lower lacinia broadly rounded, upper lacinia broadly elongated, inner edge straight, with setae and teeth. Maxilla ( Fig. 7D View Fig ) with slender palp, upper endite subdivided, scaphognathite tapering with numerous long setae posteriorly. Palp of first maxilliped ( Fig. 7E View Fig ) ending as triangular projection. Endopod of second maxilliped ( Fig. 7E View Fig ) with fused dactylus and propodal segments. Third maxilliped ( Fig. 7G View Fig ) 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 View Fig ) 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 View Fig ) 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 View Fig ) 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 View Fig ) 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 View Fig )

(B)

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 View Fig ) 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 View Fig ) 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 View Fig ) 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 View Fig ; Fig. 9C, D, E View Fig ) (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 View Fig ) (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 View Fig ) (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 View Fig ) (vs. beyond the end of the second segment of the antennular peduncle; Fig. 10A View Fig ); the more slender first pereiopod having the dactylus 2.5 times as long as broad ( Fig. 8A, B View Fig ) (vs. 1.5 times; Fig. 11A View Fig ); and the male first pleopod having an appendix interna that reaches to the distal end of the endopod ( Fig. 8E View Fig ) (vs. distinctly reaching beyond; Fig. 12 View Fig D-F).