Caridina spathulirostris Richters, 1880 Figs 2B, 5C Caridina serrata Richters, 1880: 163, pl. 17 figs 24–27 (junior homonym of Caridina serrata Stimpson, 1860). Caridina spathulirostris Richters, 1880: 163, pl. 17 fig. 28. Caridina spatulirostris f. rectirostris Bouvier, 1925: 197. Caridina spatulirostris f. curvirostris Bouvier, 1925: 197. Caridina richtersii Thallwitz, 1891: 27 (nomen novum for Caridina serrata Richters, 1880). Caridina Richtersi f. typica Bouvier, 1912c: 165; 1925: 203. Caridina apiocheles Bouvier, 1904: 134. Caridina apiocheles mutation Edwardsi Bouvier, 1904: 134. Caridina spathulirostris – Ortmann 1894b: 406 (key). — Bouvier 1905: 93 (key); 1912a: 291; 1913a: 464 (key); 1925: 197, figs 416–422. — Costa 1980: 691. — Keith et al. 2006: 60. Caridina richtersi – Ortmann 1894b: 402 (key), 404. — Edmondson 1929: 28. — Holthuis 1954: 3. — Carpenter 1978: 350. — Costa 1980: 690. — Keith et al. 2006: 54 (incorrect spelling). Caridina Richtersi – Bouvier 1904: 134; 1905: 86; 1912a 293; 1912b: 919; 1912c: 163; 1913a: 464 (key); 1913b: 184; 1914: 699; 1925: 201, figs 432–457. — Bouvier & d’Emmerez de Charmoy 1919: 317. — Woltereck 1937a: 246 (incorrect spelling). Caridina apiocheles – Bouvier 1905: 69, 86, fig. 3. — Bordage 1909: 108, fig. 6. Caridina apiocheles mutation Edwardsi – Bouvier 1905: 69, 87, 103, fig. 3; 1912c: 166. — Bordage 1909: 108, fig. 6. Caridina Richtersi f. apiocheles – Bouvier 1912a: 295; 1912c: 165; 1925: 203. Ortmannia Edwardsi – Bouvier 1912 a: 296; 1912c: 166; 1912d: 691, fig. 3; 1913a: 459 (key); 1914: 700; 1925: 265, figs 445–447, 449, 452–453, 598–605. — Bouvier & d’Emmerez de Charmoy 1919: 317. — Woltereck 1937b: 322. Caridina richtersi var. apiocheles – Bouvier 1925: 205. — Costa 1980: 690. Ortmannia edwardsi – Edmondson 1929: 28. — Holthuis 1954: 3. — Costa 1980: 699. Caridina richtersi var. typica – Costa 1980: 690. Type locality Pamplemousses Botanical Garden, Mauritius. Material examined Caridina spathulirostris Richters, 1880 MAURITIUS • 1 ♀ ovig. (cl 3.9 mm), 1 ♀ (cl 5.3 mm); quartier militaire, rivière importante; 20°17.260′ S, 57°35.948′ E; 390 m a.s.l.; 10 Dec. 2005; C.R. Turner leg.; MNHN-Na 772; MNHN • 1 ♀ (cl 5.8 mm); same data as for preceding; DNA voucher: CA2165; MNHN-2025-125; MNHN. Caridina richtersii Thallwitz, 1891 MAURITIUS • 1 ♀ ovig. (cl 5.8 mm); quartier militaire, rivière importante; 20°17.260′ S, 57°35.948′ E; 390 m a.s.l.; 10 Dec. 2005; C.R. Turner leg.; DNA voucher: CA2166; MNHN-2025-126; MNHN • 1 ♂ (cl 6.5 mm); same data as for preceding; DNA voucher: CA2167; MNHN-2025-127; MNHN. Distribution Endemic to Mauritius. Habitat Freshwater in rivers and ponds. Remarks Our genetic study shows that Caridina richtersi Thallwitz, 1891 and C. spathulirostris Richters, 1880 are conspecific and we consider the former to be a junior synonym of C. spathulirostris. The specimens of this species are polymorphic in the shape of the rostrum and the chelipeds, which led to the description of numerous forms like C. spathulirostris f. rectirostris, C. spathulirostris f. curvirostris, C. richtersi f. typica, C. richertsi f. apiocheles. This kind of variability was also described in another endemic species of Caridina from the SWIO, C. similis (see Marquet & Keith, 2008).

Published as part of Mazancourt, Valentin De, Mennesson, Marion, Marquet, Gérard & Keith, Philippe, 2025, Revision of the species of Caridina (Decapoda: Atyidae) from the Western Indian Ocean islands with description of a new species, pp. 57-86 in European Journal of Taxonomy 1007 on pages 64-65, DOI: 10.5852/ejt.2025.1007.2995, http://zenodo.org/record/16795401