Caridina aff. heterodactyla Liang and Yan, 1985

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 : 26-29

Caridina aff. heterodactyla Liang and Yan, 1985

( Figs. 19 , 20 )

Material examined: Female, cl 7.5 mm, damaged with incomplete abdomen, ZRC Tonglin Cave, near Nan Cave, Kaiyuan County, Yunnan Province, southern China, coll. B. Sket, 26 Nov 1995.

Comparative material examined: Caridina heteradactyla Liang and Yan, 1985 - Holotype: male, cl 5.6 mm, SFU, mountain stream at Sizhong County, Yunnan Province, China, 1983. Paratype: 1 female, cl 5.6 mm, SFU, mountain stream at Sizhong County, Yunnan Province, China, 1983.

Description: Rostrum ( Fig. 19A ) short, sharply downturned, reaching slightly beyond end of basal segment of antennular peduncle, dorsally with 24 teeth, of which, 12 are situated at carapace behind posterior margin of orbital margin, occupying 0.3 carapace length, armed ventrally with 7 small teeth. Antennal spine fused with suborbital angle. Pterygostomian angle rounded.

Eyes well developed ( Fig. 19A ). Stylocerite reaching slightly beyond end of basal segment of antennular peduncle. Antennular peduncle ( Fig. 20A ) 0.43 times as long as carapace. Scaphocerite ( Fig. 20B ) 2.7 times as long as wide, outer margin straight.

Mouthparts as figured. Mandible ( Fig. 19B ) with blunt teeth at extremity of incisor process. Maxillula ( Fig. 19C ) with simple palp, lower lacinia broadly rounded, upper lacinia broadly elongated, inner edge straight, with dense setae and teeth. Maxilla ( Fig. 19D ) with slender palp, upper endite subdivided, scaphognathite tapering with numerous long hooked setae posteriorly. Palp of first maxilliped ( Fig. 19E ) stout, terminating in triangular projection. Endopod of second maxilliped ( Fig. 19F ) with fused dactylus and propodal segments. Third maxilliped ( Fig. 20C ) reaching to distal end of antennular peduncle, ending in single terminal claw; exopod reaching posterior quarter of penultimate segment, ultimate segment slightly shorter than pentultimate segment. Epipods on first 4 pereiopods.

First pereiopod ( Fig. 20D ) short, stout, reaching distal margin of eye, merus 2.1 times as long as broad; carpus strong concave anteriorly, 1.3 times as long as high, chela 2.6 times as long as broad, fingers slightly longer than palm. Second pereiopod ( Fig. 20E ) reaching almost to end of second segment of antennular peduncle; carpus 3.9 times as long as high, chela shorter than carpus, 2.3 times as long as broad, fingers as long as palm. Third pereiopod ( Fig. 20F, G ) reaching beyond distal end of scaphocrite, propodus 10 times as long as broad, 4.8 times as long as dactylus (claw included); dactylus ending as 2 claws, with 5 spines on flexor margin. Fifth pereiopod ( Fig. 20H ) reaching distal end of antennular peduncle, propodus 10 times as long as wide, dactylus missing. Eggs1.2 × 0.8mm in diameter.

Habitat: Stream in karst cave.

Remarks: The single female specimen found from the Tonglin Cave in Kaiyan is morphologically closest to C. heterodactyla Liang and Yan, 1985 in the downturned rostrum, the large number of postorbital teeth on carapace, the eggs and the long stylocerite, which reaches the end of basal segment of the antennular peduncle. It can be distinguished from C. heterodactyla s. str. by the much shorter length of rostrum ( Fig. 19A ), which reaches only slightly beyond the end of the basal segment of antennular peduncle; and the shorter carpus of first pereiopod (1.3 times as long as high, Fig. 20D ) (vs. 2.0-2.3 times as long as high; cf. Liang and Yan, 1985: fig. 2(4)). We believe that the morphological differences indicate that the present specimen is probably an undescribed species. But with only a single incomplete female specimen available, we prefer to defer the naming of new species to a later stage when more specimens are available.

Distribution: Yunnan Province (Tonglin Cave), China.

Figures

Fig. 19. Caridina aff. heterodactyla Liang and Yan, 1985. (A) cephalothorax and cephalic appendages, lateral view, (B) mandible, (C) maxillula, (D) maxilla, (E) first maxilliped, (F) second maxilliped. Scale bars: A, D-F = 1.0 mm; B, C = 0.5 mm. (ovigerous female, cl 7.5 mm, ZRC).

Fig. 20. Caridina aff. heterodactyla Liang and Yan, 1985. (A) antennular peduncle, (B) scaphocerite, (C) third maxilliped, (D) first pereiopod, (E) second pereiopod, (F) third pereiopod, (G) dactylus of third pereiopod, (H) fifth pereiopod. Scale bars: A-F, H = 1.0 mm; G = 0.3 mm. (ovigerous female, cl 7.5 mm, ZRC).