Caridina ghanensis sp. nov.

(Figs. 16, 17)

Material examined. Holotype: º Republic of Ghana (former Gold coast) Pond Vume, coll. R. Bassindale, 23.3.1949, det. J. Richard and P. Clark 2007, NHM 2007.724. Paratypes: Pond Vume, coll. R. Bassindale, 23.3.1949, det. J. Richard and P. Clark 2007, NHM 2007.725–734, 5♂, 1♀ ovig., 26♀, 28 juv.; freshwater, Pond Vume, 23.3.1949, coll. R. Bassindale, RMNH D 10218, 5♂, 3♀ ovig., 32♀, 23 juv. Togo La Sio near Lomé, 5.12.1949, Don. Inst. Franç. Afr. Noire, RMNH D 19461, 1♂, 1♀.

Description. Total length: 11–23 mm. Carapace length: 2.2–3.0 mm.

Rostrum (Fig. 16a, b, c, d, e): extending from second segment of antennular peduncle to end of antennal scale. 2–3 mm in length. 0.8–1.0 × long as carapace. 10–21 (mostly 14–17) teeth on dorsal margin leaving 0.3–0.6 of length distally unarmed. 1 or 2 post-orbital teeth. 0–7 (mostly 2–5, rarely 0) teeth on ventral margin. Tip pointed or bifid. Formula (1–2) 10–23/0–7 mostly (1–2) 14–17/2–5.

Antennular peduncle (Fig. 16f): 0.7–0.9 × carapace. Stylocerite 0.6–0.8 × length of basal segment. Anterolateral teeth of basal segment 0.1–0.2 × second segment. 6–10 segments bearing aesthetascs.

First pereiopod (Fig. 17a): dactylus 0.9–1.1 × palm of propodus. Chela 2.1–2.5 × long as broad. Carpus 2.2–2.7 × long as broad, anterior excavation not deep.

Second pereiopod (Fig. 17b): dactylus 1.5–1.9 × long as palm of propodus. Chela 2.5–3 × long as broad. Carpus 4–5 × long as broad.

Third pereiopod (Fig. 17c, d): dactylus 3.2–3.8 × long as broad. Spines on dactylus varied 7–10 (including terminal spines), mostly 7 or 8. Propodus 3.3–3.9 × long as dactylus and 10.5–12 × long as broad with 6–8 spines arranged along inner margin. Carpus 0.5–0.6 × long as propodus, with 10–15 minute spines on inner margin. Merus 1.4–1.6 × carpus length. Merus with 2 large spines and fine setae along posterior margin.

Fifth pereiopod (Fig. 17e, f): dactylus 4–4.5 × long as broad with 20–40 spines arranged in comb-like fashion on inner margin. Propodus 12–14 × long as broad and 2.8–3.5 × long as dactylus with 6–10 spines arranged along posterior margin. Carpus 0.5–0.6 × propodus length and with minute spines along inner margin. Merus 1.5–1.9 × carpus length, with 2 large spines and fine setae along posterior margin.

Setobranchs: 1 on all pereiopods.

First male pleopod (Fig. 17g, h): endopod 0.25–0.30 × exopod length. Appendix interna absent. Long setae at tip slant forward giving cobra-hood appearance to endopod.

First female pleopod (Fig. 17i): endopod 0.3–0.4 × long as exopod.

Eggs (Fig. 17j): 15–20, 0.65–0.70 × 0.35–0.40 mm in size.

Second male pleopod (Fig. 17k, l, m): appendix masculina, 0.7–1.1 × appendix interna being shorter, equal to, or slightly longer than appendix interna. 0.24–0.35 × endopod.

Sixth abdominal somite: 0.7–0.9 × long as carapace.

Telson (Fig. 17n, o): tapering, 0.8–1.0 × long as sixth abdominal somite. Dorsal spines 3–4 pairs (including subterminal spine). 1 pair of plain lateral spines and 3–4 pairs or 7 or 9 finely plumose stalked processes of equal length on rounded or flattened posterior margin of telson.

Uropod (Fig. 17p, q): 4–8 (mostly 5–6) diaeresis spinules.

Preanal carina (Fig. 17r): sharp with small spine.

Remarks. Caridina ghanensis sp. nov. is distinguished by the following characters: smaller size of the adult (11–23mm), dorsal teeth of the rostrum always arranged proximally leaving the distal margin unarmed, ventral teeth of rostrum are arranged distally with a short distal unarmed margin, dactylus of the fifth pereiopod with fewer number of spines (25–40), appendix masculina shorter, equal or slightly longer than the appendix interna, a reduced number of uropod diaeresis spinules and 15–20 smaller eggs of 0.65–0.7 × 0.35–0.4 mm.

Caridina ghanensis sp. nov. is similar to C. africana with respect to the rostrum having dorsal teeth arranged proximally leaving the distal margin unarmed and terminating in a bifid tip. The new species, however, differs from C. africana in having the teeth on the ventral margin being arranged distally.

Caridina ghanensis sp. nov. is similar to C. togoensis by the arrangement of plumose processes on the posterior margin of the telson. The new species differs from C. togoensis in having a rostrum with a bifid tip (rarely acute), teeth on ventral margin being always arranged distally, 20–40 spines on the dactylus of the fifth pereiopod, a shorter appendix masculina, 4–8 (mostly 5–6) spinules on the uropod diaeresis and 15–20 smaller eggs.

Etymology. Caridina ghanensis sp. nov. is named after the Republic of Ghana from where the species was collected.