Caridina gaesumi, 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 : 57-60

publication ID

https://doi.org/ 10.5281/zenodo.1455866

DOI

https://doi.org/10.5281/zenodo.6219331

persistent identifier

https://treatment.plazi.org/id/03EF5668-745B-C728-E79D-1F02FF7CFCDC

treatment provided by

Plazi

scientific name

Caridina gaesumi
status

sp. nov.

Caridina gaesumi View in CoL sp. nov.

( Figs. 30 View FIGURE 30 , 31 View FIGURE 31 )

Material examined. Holotype: ♀ ovig. Nigeria Osse River (Ovia River) near Gilli Gilli, Midwest State, 6°9.5'N 5°21'E, 16.5.1975, coll. & pres. C. B. Powell, RMNH D 30480 View Materials . Paratypes: Lagune of Ogba River, S of Ogba, Midwest State, 6°17'N 5°35'E, 16 and 22.5.1975, coll. & pres. C. B. Powell, RMNH D 30479 View Materials , 7♀ ovig., 3♀; Osse River (Ovia River) near Gilli Gilli, Midwest State; 6°9.5'N 5°21'E, 16.5.1975, coll. & pres. C. B. Powell, RMNH D 30480 View Materials , 5♀ ovig., 3♀. Republic of Zambia Irrigation ditch, Nakambala Sugar estate, Mazabula, 29.6.1981, pres. J. Pollock, NHM 1982.139, 1♂.

Description. Total length: 14–23 mm. Carapace length: 2.9–3.2 mm.

Rostrum ( Fig. 30a, b, c View FIGURE 30 ): reaching apex of antennal scale. 2.4–2.8 mm in length. 0.8–0.9 × carapace. 10–20 teeth on dorsal margin leaving 0.3–0.4 of length distally unarmed sometimes interrupted by 1–2 teeth. 1–3 post-orbital teeth. 3–9 teeth on ventral margin arranged to tip. Tip pointed or bifid. Formula (1–3) 10–20/ 3–9.

Antennular peduncle ( Fig. 30d View FIGURE 30 ): 0.65–0.75 × carapace. Stylocerite 0.7–0.9 × length of basal segment. Anterolateral teeth of basal segment 0.25–0.4 × second segment. 5–9 segments bearing aesthetascs.

First pereiopod ( Fig. 31a View FIGURE 31 ): dactylus 1.3–1.4 × palm of propodus. Chela 2.4–2.5 × long as broad. Carpus 2.3–2.5 × long as broad with anterior excavation.

Second pereiopod ( Fig. 31b View FIGURE 31 ): dactylus 1.1–1.2 × long as palm of propodus. Chela 3.1–3.3 × long as broad. Carpus 6.5–7.1 × long as broad.

Third pereiopod ( Fig. 31c, d View FIGURE 31 ): dactylus 2.5–3 × long as broad.4–9 spines on dactylus (including terminal spines). Propodus 5–5.2 × long as dactylus and 13.5–15 × long as broad with 7–10 spines along posterior margin. Carpus 0.5–0.6 × long as propodus, with minute spines on inner margin. Merus 1.5–1.7 × carpus length. Merus with 4 spines on posterior margin.

Fifth pereiopod ( Fig. 31e, f View FIGURE 31 ): dactylus 2.4–2.6 × long as broad with 25–45 spines arranged in comb-like fashion on inner margin. Propodus 13–14 × long as broad and 3.5–4.0 × long as dactylus with 9–12 spines along inner margin. Carpus 0.5–0.6 × propodus length and with minute spines along inner margin. Merus 1.5–1.6 × carpus length, with 2 spines along inner margin.

Setobranchs: 2 on all pereiopods.

First male pleopod ( Fig. 31g, h View FIGURE 31 ): endopod 0.4 × exopod; appendix interna absent. Short setae present on margin.

First female pleopod ( Fig. 31i View FIGURE 31 ): endopod 0.5–0.6 × long as exopod.

Eggs ( Fig. 31j View FIGURE 31 ): 10–15, 0.9–1.1 × 0.5–0.6 mm in size.

Second male pleopod ( Fig. 31k View FIGURE 31 ): appendix masculina 1.3 × appendix interna. 0.35 × endopod. Several stalked spines along posterior margin.

Sixth abdominal somite: 0.6–0.7 × long as carapace.

Telson ( Fig. 31m, n, o View FIGURE 31 ): 1–1.1 × long as sixth abdominal somite. 4–5 pairs of dorsal spines (including sub terminal spines). Broad with pair of longer lateral spines almost reaching 0.6–0.9 of inner plumose process. 1–3 pairs or 3 or 5 stalked plumose processes present at posterior margin.

Uropod ( Fig. 31p View FIGURE 31 ): 7–10 diaeresis spinules.

Preanal carina ( Fig. 31q View FIGURE 31 ): Sharp with spine or unarmed.

Remarks. Caridina gaesumi sp. nov. is distinguished by the following characters: rostrum straight, reaching apex of antennal scale, dorsal teeth 10–20, arranged up to the tip or leaving the 0.3–0.4 of the dorsal distal margin plain, which is interrupted by teeth; 3–9 teeth on the ventral margin of the rostrum arranged from the proximal end up to the tip; tip of the rostrum pointed or bifid; 20–45 spines on the dactylus of the fifth pereiopod; few eggs in ovigerous females (10–15); and longer lateral spines on the posterior margin of the telson.

Caridina gaesumi is similar to C. togoensis in the arrangement of teeth on the dorsal margin of the rostrum, either compactly arranged up to the tip or with a short distal unarmed margin, and in bearing plumose processes at the posterior margin of the telson. However, the unarmed dorsal distal margin, when present, could be interrupted by teeth in C. gaesumi sp. nov. whereas it is plain in C. togoensis . Also the tip of the rostrum could be either pointed or bifid in C. gaesumi sp. nov. whereas it is pointed in C. togoensis . Caridiana gaesumi sp. nov. differs from C. togoensis in possessing comparatively longer lateral spines on the posterior margin of the telson.

Etymology. The specific name is derived from g aesum, Latin, meaning a long heavy javelin, referring to the distinguishing character of this species, namely the long lateral spines on the posterior margin of the telson.

RMNH

National Museum of Natural History, Naturalis

NHM

University of Nottingham

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Atyidae

Genus

Caridina

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