Caridina okiamnis , Jasmine Richard & Paul F. 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, Zootaxa 1995, pp. 1-75: 54-57

publication ID

10.5281/zenodo.1455866

persistent identifier

http://treatment.plazi.org/id/03EF5668-7456-C72B-E79D-1ECFFCBFFDF4

treatment provided by

Plazi

scientific name

Caridina okiamnis
status

sp. nov.

Caridina okiamnis  sp. nov.

( Figs. 28 View Figure , 29 View Figure )

Material examined. Holotype: ♀ ovig. Cameroon Okia stream, 10.11.70, coll. R. H. L. Disney, NHMAbout NHM 1974.694. Paratypes: Okia stream, 14.11.68, coll. R. H. L. Disney, NHMAbout NHM 1974.693, 1♀ ovig., 2♀.

Description. Total length: 20–22 mm. Carapace length: 3.7–4 mm.

Rostrum ( Fig. 28a, b, c View Figure ): equal to antennal scale, 3.7–3.9 mm in length. 0.85–0.95 × carapace. 20–22 teeth on dorsal margin leaving 0.28–0.30 of length distally unarmed. 5 post-orbital teeth. 10–11 teeth on ventral margin arranged to tip. Tip pointed. Formula (5) 20–22/10–11.

Antennular peduncle ( Fig. 28d View Figure ): 0.75 × carapace. Stylocerite 0.6–0.9 × length of basal segment. Anterolateral teeth of basal segment 0.42 × second segment. 8–10 segments bearing aesthetascs.

First pereiopod ( Fig. 29a View Figure ): dactylus 1.2–1.3 × palm of propodus. Chela 2.2 × long as broad. Carpus 2–2.15 × long as broad with deep excavation.

Second pereiopod ( Fig. 29b View Figure ): dactylus 1.2–1.25 × long as palm of propodus. Chela 2.75–2.8 × long as broad. Carpus 4–4.25 × long as broad.

Third pereiopod ( Fig. 29c, d View Figure ): dactylus 2.1–2.2 × long as broad. Spines on dactylus varying from 6–8 (including terminal spines). Propodus 6.5–6.8 × long as dactylus and 13.5–14.5 × long as broad with 12–15 spines arranged along posterior margin. Carpus 0.56 × long as propodus, with minute spines on inner margin. Merus 1.9–2 × carpus length. Merus with 2 spines on posterior margin.

Fifth pereiopod ( Fig. 29e, f View Figure ): dactylus 3.4–3.5 × long as broad with 30–50 spines arranged in comb-like fashion on inner margin. Propodus 12–13 × long as broad and 4.1–4.2 × long as dactylus with 15–20 spines arranged along inner margin. Carpus 0.55–0.6 × propodus length and with minute spines along inner margin. Merus 1.4–1.5 × carpus length and with 1 spine along inner margin.

Setobranchs: 2 on all pereiopods.

First female pleopod ( Fig. 29g View Figure ): endopod 0.75 × long as exopod.

Eggs ( Fig. 29h View Figure ): 9–10, 1.05–1.13 × 0.55–0.68 mm in size.

Sixth abdominal somite: 0.57 × long as carapace.

Telson ( Fig. 29i, j View Figure ): 1–1.1 × long as sixth abdominal somite. Dorsal spines 5 pairs (including subterminal spine). Broad with flat posterior margin bearing 1 pair of longer lateral spines and 3 pairs of plumose processes increasing in length towards centre giving triangular appearance.

Uropod ( Fig. 29k, l View Figure ): 14–16 diaeresis spinules.

Preanal carina ( Fig. 29m View Figure ): peg-like and unarmed.

Remarks. Caridina okiamnis  sp. nov. is distinguished by the combination of: straight rostrum having the dorsal distal margin unarmed with a pointed tip; ventral margin of rostrum characteristically arched with 10 or 11 teeth evenly arranged up to the tip; the rostrum has 5 post-orbital teeth; overigerous females with few eggs (10 or 11); the telson is broad with a flat posterior margin possessing comparatively longer lateral spines and short plumose processes arranged on a flat posterior margin giving a triangular appearance; and the uropod diaeresis possesses 14–16 spinules. Unfortunately, the type series does not include males.

Etymology. The name, okiamnis  , is a combination of the name Okia, stream from which the type material was collected, and the Latin, amnis, meaning stream.

NHM

University of Nottingham

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Atyidae

Genus

Caridina