Caridina longshan, 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 : 2-5

Caridina longshan sp. nov.

( Figs. 1-3 )

urn:lsid:zoobank.org:act:866065C2-69B7-4EB1-9110-5B4A30487650

M a t e r i a l e x a m i n e d: H o l o t y p e: m a l e, c l

8.0 mm, IZCAS DE 5028, stream at end of cave, Panon Cave, Huaoyan Village, Longshan County , Hunan Province southern China, coll. Cao and B. Sket, 13 Apr 1997. Paratypes: 2 males, cl 6.6- 9.0 mm; 1 female, cl 6.5 mm, ZRC 2018.0480, same data as holotype; 1 female, cl 7.0 mm, UL, same data as holotype; 1 female, cl 6.8 mm, RMNH.CRUS.D.57289, Cave of Flying Tiger, Hoyan Village, Longshan County , Hunan, coll. L. Deharveng and A. Bedos, 14 Aug 1995; 1 male, cl 8.8 mm, ZRC 2018.0489, 1 female, cl 7.4 mm, UL, Parking Cave, near Hoyan Village, coll. Canto and Delprat, 25 Aug 1995.

Comparative material examined: Caridina cavaleriei cavaleriei Bouvier, 1919 - Syntype 1 female, MNHN Na 689, Gan-chouen-fou, Kouy- Tcheou (Guizhou), China. Caridina dentifrons NK Ng and Cai, 2000 - Paratypes: 2 males, cl 4.7 mm, 1 female, cl 5.2 mm, ZRC 1997.593, Baijin Village, Huishui County, Guizhou Province, China, coll. 16 May 1983.

Description: Rostrum long ( Fig. 1 A-D), reaching from end of antennular peduncle to end of scaphocerite, anterior half distinctly upturned, armed dorsally with 18-21 slender teeth, of which 6 or 7 teeth situated on carapace behind posterior margin of orbit, occupied 0.25-0.33 carapace length, armed ventrally with 12-17 teeth, of which posterior 4 or 5 teeth are wider separated than others. Antennal spine sharp, completely fused with suborbital angle; pterygostomian margin broadly rounded.

Sixth abdominal somite 1.8 times as long as fifth abdominal somite, as long as telson. Telson ( Fig. 2K, L ) without posteriomedian projection, lateral pair of spines on posterior margin longer than intermediate pairs, surface of proximal half covered by fine setae and spinules. Sublateral pair of spines shortest.

Eyes degenerated ( Fig. 1 A-D), eye stalk absent, cornea pigmentation variable, from totally absent to with small black spot. Antennular peduncle slender ( Fig. 1E ), about half carapace length. Stylocerite sharp, long, reaching near end of basal segment of antennular peduncle. Scaphocerite 2.8 times as long as wide ( Fig. 1F ).

Mouthparts as figured. Mandible with blunt teeth at extremity of incisor process ( Fig. 2A ). Maxillula with simple palp, lower lacinia broadly rounded, upper lacinia broadly elongated, inner edge straight, with dense setae and teeth ( Fig. 2B ). Maxilla with slender palp, upper endite subdivided, scaphognathite tapering with numerous long hooked setae posteriorly ( Fig. 2C ). Palp of first maxilliped stout, terminating in sub-acute angle ( Fig. 2D ). Endopod of second maxilliped with fused dactylus and propodal segments ( Fig. 2E ). Third maxilliped ending in single terminal claw; exopod reaching posterior quarter of penultimate segment ( Fig. 2F, G ). Epipods on first 4 pereiopods.

First pereiopod very stout ( Fig. 3A ), reaching to middle of basal segment of antennular peduncle; merus 3.0 times as long as wide, carpus 1.9 times as long as high; chela 2.7 times as long as broad, fingers 1.2 times as long as palm. Second pereiopod ( Fig. 3B ) reaching to middle of second segment of antennular peduncle; merus as long as carpus; carpus longer than chela, 5.8 times as long as high; chela 3.1 times as long as broad; fingers 1.5 times as long as palm. Third pereiopod ( Fig. 3C, D ) reaching with dactylus beyond the distal end of scaphocerite, propodus 12 times as long as wide, 4.3 times as long as dactylus (claw included); dactylus ending in 2 claws, with 7 or 8 accessory spines increasing in length and size distally on flexor margin. Fifth pereiopod ( Fig. 3E, F, G ) reaching slightly beyond end of antennular peduncle but not beyond distal end of scaphocerite, propodus 15 times as long as wide, 3.2 times as long as dactylus; dactylus with 42-49 spinules on flexor margin.

Endopod of male first pleopod sub-elliptical ( Fig. 2H, I ), inner margin straight, reaching 0.4 exopod length, distal half curved posteriorly, 2.2-2.5 times as long as wide, appendix interna reaching to distal end of endopod. Appendix masculina of male second pleopod short ( Fig. 2J ), reaching to middle of endopod; appendix interna of male second pleopod stout.

Uropodal diaeresis with 11 or 12 spinules ( Fig. 2M ).

Habitat: Stream in karst caves.

Etymology: Caridina longshan sp. nov. is named after its type locality in Longshan County. The name is used as a noun in apposition.

Remarks: Caridina longshan sp. nov. is morphologically similar to C. cavaleriei cavaleriei Bouvier, 1919 , a subspecies known only from the original specimens from Guizhou Province, southern China. It can be distinguished by its strongly upturned rostrum ( Fig. 1 A-D) (vs. straight in C. cavaleriei cavaleriei ; cf. Bouvier, 1925: figure 544) and degenerated eyes ( Fig. 1 A-D) (vs. clearly developed in C. cavaleriei cavaleriei ; cf. Bouvier, 1925: fig. 544). With the long and upturned rostrum, Caridina longshan sp. nov. morphology resembles that of C. dentifrons NK Ng and Cai, 2000 , from Guizhou. It could be easily separated by its larger number of ventral rostral teeth (12- 17 vs. 4-8 in C. dentifrons ; cf. NK Ng and Cai, 2000: fig. 1A-C), degenerated eyes ( Fig. 1 A-D) (vs. clearly developed in C. dentifrons ; cf. NK Ng and Cai, 2000: fig. 1A-C) and dactylus of third pereiopod with 7 or 8 accessory spines on flexor margin ( Fig. 3D ) (vs. 6 spines in C. dentifrons ; cf. NK Ng and Cai, 2000: fig. 3E)

Two characters of this species are unusual: the pigmentation in the cornea of eyes and the presence of spinules on the surface of distal spines (serrated setae in Garms and Watling 2013) of telson ( Fig. 2K, L ). The condition of the eye cornea pigmentation ranges from totally absent to just a black spot ( Fig. 1 A-D). The adaptive significance of the serrated setae of the telson is not known.

Distribution: Hunan Province (Longshan), China.

Figures

Fig. 1. Caridina longshan sp. nov. (A-D) cephalothorax and cephalic appendages, lateral view, (E) antennular peduncle, ventral view, (F) scaphocerite, (G) preanal carina. Scale bars: A-D, F = 2.0 mm; E = 1.0 mm; G = 0.5 mm. (A, E-G, male, cl 8.8 mm, Parking Cave, near Hoyan Village, Longshan County, paratype, ZRC 2018.0489; B. female, cl 7.4 mm, Parking Cave, near Hoyan Village, Longshan County, Hunan Province, paratype, UL; C, female, cl 6.5 mm, Panon Cave, Huaoyan Village, Longshan County, Hunan Province, paratype, ZRC 2018.0480; D, female, cl 6.8 mm, Cave of flying Tiger, Hoyan Village, Longshan County, Hunan Province, paratype, RMNHCRUS.D.57289).

Fig. 2. Caridina longshan sp. nov. (A) mandible, (B) maxillula, (C) maxilla, (D) first maxilliped, (E) second maxilliped, (F) third maxilliped, (G) distal portion of third maxilliped, (H) male first pleopod, (I) endopod of male first pleopod, (J) male second pleopod, (K) distal portion of telson, (L) sublateral spine, right, (M) uropodal diaeresis. Scale bars: A-F = 1.0 mm; G-J, M = 0.5 mm; K = 0.2 mm; L = 0.1 mm. (A-G, K, L, female, cl 6.5 mm, Cave of Panon, Huaoyan Village, Longshan County, Hunan Province, Paratype, ZRC 2018.0480; H, J, cl 8.8 mm, male, Parking Cave, near Hoyan Village, Longshan County, paratype, ZRC 2018.0489).

Fig. 3. Caridina longshan sp. nov. (A) first pereiopod, (B) second pereiopod, (C) third pereiopod, (D) dactylus of third pereiopod, (E) fifth pereiopod, (F) propodus and dactylus of fifth pereiopod, (G) dactylus of fifth pereiopod. Scale bars: A-C, E, F = 1.0 mm; D, G = 0.2 mm. (A-E, G, female, female, cl 6.5 mm, Panon Cave, Huaoyan Village, Longshan County, Hunan Province, paratype, ZRC 2018.0480; F, wanting leg of another specimen, same location).