Caridina lineorostris, Richard & Clark, 2009

Jasmine Richard & Paul F. Clark, 2009, African Caridina (Crustacea: Decapoda: Caridea: Atyidae): redescriptions of C. africana Kingsley, 1882, C. togoensis Hilgendorf, 1893, C. natalensis Bouvier, 1925 and C. roubaudi Bouvier, 1925 with descriptions of 14 new species, Zootaxa 1995, pp. 1-75 : 51-54

Caridina lineorostris sp. nov.

( Figs. 26 , 27 )

Material examined. Holotype: ♂ Gabon Keri, Forest stream, 20 km North of Lambarene, 15.11.1984, NHM 1988: 35. Paratypes: 0°34.5'S 10°28.4'E, 5.4.1994, in small stream; coll. & pres. J. J. Wieringa & R. M. A. P. Haegens, RMNH D 45560, 3♂; Keri, Forest stream, 20 km North of Lambarene, 15.11.1984, NHM 1988.35, 21♂, 18♀ ovig., 7♀.

Description. Total length: 22–28 mm. Carapace length: 3.85–3.9 mm.

Rostrum ( Fig. 26a, b, c ): Straight, equal to or fractionally longer than antennal scale. 3.9–4 mm in length. Equal to or fractionally longer than carapace. 22–34 teeth on dorsal margin arranged to tip. 3–5 post-orbital teeth. 3–15 teeth on ventral margin leaving distal end unarmed. Tip pointed. Formula (3–5) 22–34/3–15, mostly (4–5) 25–31/7–15.

Antennular peduncle ( Fig. 26d ): 0.75 × carapace. Stylocerite 0.7–90 × length of basal segment. Anterolateral teeth of basal segment 0.4–0.5 × second segment. 5–21 segments bearing aesthetascs.

First pereiopod ( Fig. 27a ): dactylus 1.1–1.2 × palm of propodus. Chela 1.9–20 × long as broad. Carpus 2.2–2.3 × long as broad with shallow excavation at anterior margin.

Second pereiopod ( Fig. 27b ): dactylus 1.4 × long as palm of propodus. Chela 2.57 × long as broad. Carpus 5.5 × long as broad.

Third pereiopod ( Fig. 27c, d ): dactylus 2.3–2.5 × long as broad. Spines on dactylus ranging from 6–9 (including terminal spines). Propodus 4.8–5.5 × long as dactylus and 9–11 × long as broad with 10–12 spines arranged along posterior margin. Carpus 0.6–0.7 × long as propodus, with minute spines on inner margin. Merus 1.8–2 × carpus length. Merus with 3 spines on posterior margin.

Fifth pereiopod ( Fig. 27e, f ): dactylus 3.6 × long as broad with 45–55 spines arranged in comb-like fashion on inner margin. Propodus 12–13 × long as broad and 3.2–4 × long as dactylus with 10–11 spines along inner margin. Carpus 0.6–0.7 × propodus length and with minute spines along inner margin. Merus 1.5–1.7 × carpus length, with 3 spines at posterior margin.

Setobranchs: 2 on all pereiopods.

First male pleopod ( Fig. 27g, h ): endopod 0.35–0.45 × exopod length. Appendix interna absent. Several long, stalked setae arranged along outer margin and short stalked setae along inner margin.

First female pleopod ( Fig. 27i ): endopod 0.5–0.6 × exopod.

Eggs ( Fig. 27j ) 20–30, 1–1.1 × 0.6–0.65mm in size.

Second male pleopod ( Fig. 27k, l ): appendix masculina1.4–1.5 × appendix interna. 0.3–0.4 × endopod.

Sixth abdominal somite: 0.7 × long as carapace.

Telson ( Fig. 27m, n ): 0.9–1 × long as sixth abdominal somite. Dorsal spines 4–6 pairs (including sub terminal spine). 1 pair of long lateral spines and 2–3 pairs (mostly 2 pairs) or 5 slender stalked plumose processes of equal length, present at posterior margin.

Uropod ( Fig. 27o, p ): 6–12 diaeresis spinules.

Preanal carina ( Fig. 27q ): unarmed.

Remarks. Caridina lineorostris sp. nov. is unique in the combination of a straight rostrum, with the apex reaching or fractionally overreaching the antennal scale, having more teeth on the dorsal margin (22–34) arranged compactly up to the tip; ventral teeth 3–15 arranged compactly on proximal ventral margin leaving distal 0.2–0.6 of ventral margin always unarmed; 3–5 post-orbital teeth; telson tapering with a pair of longer lateral spines and with 2 pairs or 5 slender stalked plumose processes of equal length at posterior margin and fewer number of eggs (20– 30 eggs).

The straight, long, rostrum and the characteristic arrangement of the teeth on the rostrum distinguishes C. lineorostris sp. nov. from C. africana and C. togoensis .

Etymology. Caridina lineorostris sp. nov. is named from the Latin meaning straight rostrum.

Figures

FIGURE 26. Caridina lineorostris sp. nov., RMNH 45560, ♂: a) Entire; b) Anterior region of cephalothorax. NHM 1988: 35:50, ♀: c) Anterior region of cephalothorax. RMNH 45560, ♂: d) Antennular peduncle.

FIGURE 27. Caridina lineorostris sp. nov., RMNH 45560, ♂: a) First pereiopod; b) Second pereiopod; c) Third pereiopod; d) Dactylus of third pereiopod; e) Fifth pereiopod; f) Dactylus of fifth pereiopod; g) First pleopod; h) Endopod of first pleopod. NHM 1988:35: 50, ♀ ovig.: i) First pleopod; j) Eggs. RMNH 45560, ♂: k) Second pleopod; l) Appendix masculina; m) Telson; n) Posterior margin of telson; o) Uropod; p) Uropod diaeresis spinules; q) Preanal carina.