Caridina natalensis Bouvier, 1925

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 : 22-25

Caridina natalensis Bouvier, 1925 comb. nov.

( Figs. 7 , 8 )

Caridina africana, De Man in Weber et al., 1897: 170 –174, fig. 2; Lenz, 1912: 5.

Caridina africana forme natalensis Bouvier, 1925: 214 .

Caridina nilotica.— Barnard, 1950: 662.

Material examined. Holotype: ♂ South Africa Umholti River, Verulum, Natal, coll. Weber, 1895, det. De Man 1897 as Caridina africana , det. Bouvier, 1925 as Caridina africana forme natalensis , ZMA De 202881.

Description of holotype. Total length: 25 mm. Carapace length: 4.68 mm.

Rostrum ( Fig. 7a, b ): straight, reaching ¾ of third segment of antennular peduncle. 3.21 mm in length. 0.68 × long as carapace. 10 teeth on dorsal margin leaving 0.42 of length distally unarmed. 1 post-orbital tooth. 4 teeth arranged distally on ventral margin beneath unarmed dorsal margin. Tip pointed. Formula (1) 10/4.

Antennular peduncle ( Fig. 7c ): 0.73 × carapace. Stylocerite 0.7 × length of basal segment. Anterolateral teeth of basal segment 0.15 × second segment. 20 segments bearing aesthetascs.

First pereiopod ( Fig. 8a ): dactylus 1.2 × palm of propodus. Chela 1.96 × long as broad. Carpus 1.8 × long as broad, anterior excavation deep.

Second pereiopod ( Fig. 8b ): dactylus 2.23 × long as palm of propodus. Chela 2.36 × long as broad. Carpus 5 × long as broad.

Third pereiopod ( Fig. 8c, d ): dactylus 2.3 (3 × according to De Man 1897) × as long as breadth and bearing 7 spines (including terminal spine). Propodus 4.8 (4 × according to De Man 1897) × dactylus and 7.25 (9 × according to De Man, 1897) × long as broad with numerous minute spines arranged along inner margin. Carpus 0.66 × long as propodus, with large spine at anterior end and 2 minute spines on inner margin. Merus broad, 1.94 × carpus length. Merus with 1small and 3 large spines on posterior margin.

Fifth pereiopod ( Fig. 8e, f ): dactylus 2.55 × long as broad with 21 spines arranged in comb-like fashion on inner margin. Propodus 8.5 × long as broad and 4.5 × long as dactylus with 14 minute spines arranged along inner margin with large spine at tip. Carpus 0.59 × propodus length and with large spine at anterior end and with minute spines along inner margin. Merus 1.43 × carpus length, with 3 large spines at posterior margin.

Setobranchs: 3 on all pereiopods.

First pleopod of male ( Fig. 8g, h ): endopod broad and large, 0.93 × exopod length. Appendix interna present.

Second male pleopod ( Fig. 8i, j ): appendix masculina remarkably long, 4.82 × appendix interna and 1.1 × endopod. Several small spines present on entire surface of anterior half.

Sixth abdominal somite: 0.6 × long as carapace.

Telson ( Fig. 8k, l ): Tapering uniformly to rounded posterior margin bearing subterminal median spine. 1.03 × long as sixth abdominal somite. Dorsal spines 6 pairs (including sub terminal spine). Pair of inwardly curved lateral spines and 7 long, stalked plumose processes present at posterior margin, median being longest.

Uropod ( Fig. 8m ): 15 diaeresis spinules.

Preanal carina ( Fig. 8n ): protruding and peg-like with spine.

Remarks. De Man (in Weber et al. 1897), who identified his one male specimen from Umhloti river near Verulum, Natal as C. africana , considered the descriptions of Kingsley (1882) and Ortmann (1894) to be brief, and attempted to provide a detailed description of the species based on his specimen. He illustrated and described his male, which was re-examined and illustrated here ( Figs. 7 , 8 ) for the present study. It is evident that the C. africana of De Man (in Weber et al. 1897) is different from that of Kingsley (1882). The specimen is distinct in having rostral formula (1) 10/4; teeth on dorsal margin arranged proximally with 0.42 of distal margin unarmed, teeth on ventral margin arranged distally, beginning beneath last dorsal teeth, dactylus of third pereiopod with seven spines including terminal spine, propodus 4.8 × the dactylus and 7.25 × the length by breadth, with several minute spines along posterior margin giving a serrated appearance; dactylus of fifth pereiopod 2.55 × the length by breadth, with 21 spines and a terminal spine, propodus 4.5 × the dactylus with 14 spines along posterior margin, first pleopod of male with remarkably large broad endopod that is 0.93 × the exopod adorned with minute spines along the inner margin and with setae along outer margin and with appendix interna, second pleopod with a long appendix masculina 4.82 × the appendix interna and 1.1 × the endopod, telson with a rounded posterior margin with a median protrusion and 7 pinnate plumose processes and one pair of inwardly curved lateral spines, uropod diaeresis spinules 15, preanal carina peg-like with a spine.

The C. africana of De Man (in Weber et al. 1897) differs from that of Kingsley (1882), in having fewer post-orbital teeth, fewer teeth on ventral margin that are arranged distally, a pointed tip of the rostrum, the presence of minute spines on the propodus of the third pereiopod, the presence of spine on the anal carina and in possessing a subterminal median spine and 7 long plumose processes at the posterior margin of the telson. It is also unique in possessing a large, broad endopod with appendix interna on the first pleopod and long appendix masculina that overreaches the exopod on the second pleopod.

Bouvier (1925) assigned the specimen of De Man to a new taxon, C. africana forme natalensis . The present examination confirmed that the specimen is distinct from C. africana , as well as from C. togoensis and is herein recognized as a distinct species. The remark of Barnard (1950) about this species, “I am inclined to think that it is really only an aberration of nilotica ” appears to be casual because C. natalensis ( Bouvier, 1925) differs from C. nilotica mainly in the possession of 7 long plumose processes on the posterior margin of the telson. The spines on the posterior margin of the telson of C. nilotica are 1–3 pairs (mostly 1 pair) of short spinose structures. However C. natalensis ( Bouvier, 1925) resembles the C. africana of Kingsley (1882) in having 15 uropod diaeresis spinules (in Kingsley’s specimen it is 14), and it is closer to C. togoensis in having 7 long plumose processes on the posterior margin of the telson.

Examination of an extensive collection of C. natalensis comb. nov. from the type locality would provide more information on variation in rostral formula, egg size and number of eggs carried by the species.

Figures

FIGURE 7. Caridina natalensis Bouvier, 1925 comb. nov., ZMA De 202881, Holotype ♂: a) Entire; b) Anterior region of cephalothorax; c) Antennular peduncle.

FIGURE 8. Caridina natalensis Bouvier, 1925 comb. nov., ZMA De 202881, Holotype ♂: 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 diaeresis spinules; n) Preanal carina.