Caridina messofluminis, 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 : 66-69

Caridina messofluminis sp. nov.

( Figs. 36 , 37 )

Material examined. Holotype: ♂ Cameroon Mess stream, coll. R. H. L. Disney, 5.11.1970, NHM 1974.707. Paratypes: Mess stream, coll. R. H. L. Disney, 5.11.1970, NHM 2007.747–756, (ex 1974. 707) 13♂.

Description. Total length: 15–25 mm. Carapace length: 2.5–4.5 mm.

Rostrum ( Fig. 36a, b, c ): short, equal to, or overreaching first segment of antennular peduncle. 0.9–1.25 mm in length. 0.25–0.36 × carapace. 2–9 teeth on dorsal margin leaving 0.3–0.6 of length distally unarmed. 1–5 post-orbital teeth. Teeth absent on ventral margin. Tip pointed. Formula (1–5) 2–9/0.

Antennular peduncle ( Fig. 36d ): 0.45–0.6 × carapace. Basal segment of antennular peduncle with stylocerite reaching 0.8–0.9 × basal segment. Anterolateral tooth of basal segment short being 0.08 to 0.1 × second segment. 9–11 segments bearing aesthetascs.

First pereiopod ( Fig. 37a ): dactylus 1.1–1.4 × palm of propodus. Chela 2.1–2.4 × long as broad. Carpus 2.2–2.5 × long as broad. Carpus with deep excavation anteriorly.

Second pereiopod ( Fig. 37b ): dactylus 1.3–1.55 × long as palm of propodus. Chela 2.7–3.0 × long as broad. Carpus 4.5–5.0 × long as broad.

Third pereiopod ( Fig. 37c, d ): dactylus 2–2.8 × long as broad with 5–7 spines (including spine at anterior end). Propodus 4.5–5.0 × long as dactylus and 8–9 × long as broad. 7–10 spines arranged along posterior margin. Carpus 0.6–0.7 × propodus. Merus 1.5–1.7 × carpus with 3 large spines.

Fifth pereiopod ( Fig. 37e, f ): dactylus 3.5–3.8 × long as broad with 55–65 spines arranged in comb-like fashion on posterior margin. Propodus 3.4–3.7 × long as dactylus and 10–11 × long as broad. Merus 1.3–1.4 × carpus and with three spines on posterior margin.

Setobranchs: 3 on all pereiopods.

First male pleopod ( Fig. 37g, h ): endopod long 0.6–0.7 × exopod and with short appendix interna. Short stalked setae arranged uniformly around inner margin and longer ones along outer margin.

Second male pleopod ( Fig. 39i, j ): appendix masculina 1.5–1.6 × appendix interna and 0.4–0.55 × exopod.

Sixth abdominal segment: 0.45–0.6 × long as carapace.

Telson ( Fig. 37k, l ): 5 to 6 pairs of dorsal spines (including subterminal spines). Posterior margin rounded with 1 plain lateral spines and 3–4 pairs of long, stalked densely plumose processes. 1–1.2 × long as sixth abdominal segment.

Uropod ( Fig. 37m, n ): 20–22 diaeresis spinules.

Preanal carina ( Fig. 37o ): Protruding and peg-like without spines and adorned with long setae at tip.

Remarks. The short, pointed rostrum (not reaching the end of the eye in three specimens, and slightly overreaching the first segment of the antennular peduncle in 9 specimens), with 2–9 teeth on dorsal margin of the rostrum arranged proximally leaving 0.3 to 0.5 of the dorsal margin of the rostrum unarmed, and no teeth on the ventral margin, differentiate this species from C. africana and C. togoensis . Caridina messofluminis sp. nov. is closer to C. gabonensis J. Roux, 1927 . However, C. messofluminis sp. nov. differs from C. gabonensis in having relatively fewer post-orbital teeth; 1–5 and 3–6 respectively. Caridina messofluminis sp. nov. possesses no teeth on the ventral margin of the rostrum, but, Roux (1927) reported that 15 of the specimens examined by him had one tooth on the ventral margin of the rostrum. Caridina messofluminis sp. nov. possesses 20–22 uropod diaeresis spines, while only 15 or 16 are present in C. gabonensis . The endopod of the first pleopod of the male in C. messofluminis sp. nov. is long, about 0.6–0.7 × as long as the exopod, and bears a short appendix interna. No information is available on this character in C. gabonensis . Examination of extensive collections from type locality might provide further support for the distinctness of C. messofluminis sp. nov. Based on the differences in the absence of ventral teeth, fewer post-orbital teeth, more uropod diaeresis spinules and longer endopod on the first pleopod of male with a short appendix interna, C. messofluminis sp. nov. is described as a new species. Females are not presently known.

Etymology. The species name is derived from Flumineus, Latin, meaning river, and the Mess stream, the type locality.

Figures

FIGURE 36. Caridina messofluminis sp. nov., NHM 2007.747–756, ♂1: a) Entire; b) Anterior region of Cephalothorax. ♂2: c) Anterior region of cephalothorax. Male 1: d) Antennular peduncle.

FIGURE 37. Caridina messofluminis sp. nov., NHM 2007.747–756, ♂: 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; i) Second pleopod; j) Appendix masculina; k) Telson; l) Posterior margin of telson; m) Uropod; n) Uropod diaeresis spinules; o) Preanal carina.

FIGURE 39. Caridina malawensis sp. nov., RMNH D 30477, ♀ ovig.: 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) Eggs; i) Telson; j) Posterior margin of telson; k) Uropod; l) Uropod diaeresis spinules; m) Preanal carina.