Caridina futunensis, Mazancourt & Marquet & Keith, 2019

Mazancourt, Valentin de, Marquet, Gérard & Keith, Philippe, 2019, Revision of freshwater shrimps belonging to Caridina weberi complex (Crustacea: Decapoda: Atyidae) from Polynesia with discussion on their biogeography, Journal of Natural History 53 (13), pp. 815-847 : 822-825

Caridina futunensis n. sp.

( Figure 3 )

Caridina weberi – Keith and Marquet 2011: 42 – 43 ; Mary et al. 2006: 33.

Material examined

Type material. Holotype: 1 ♀ ovig, cl 2.8 mm, 14 October 2004, 14°17.278 ′ S 178° 09.037 ʹ W, Leava river , Futuna, altitude 97m, G. Marquet, P. Keith & N. Mary coll., MNHN- IU-2018 – 195 (DNA: CA2118 ).

Paratypes: 1 ♀ ovig, cl 2.6 mm, same data as for holotype, MNHN-IU-2018 – 208 (DNA: CA2119 ); 1 ♀ ovig, cl 2.9 mm, same data as for holotype, MNHN-IU -2018 – 209 (DNA: CA2116 ); 1 ♀ ovig, cl 3.1 mm, same data as for holotype, MNHN- IU-2017 – 1460 (DNA: CA2032 ); 1 ♀ ovig, 3.1 mm, same data as for holotype, MNHN-IU - 2017 – 64 (DNA: CA2117 ); 1 ♀, cl 3.0 mm, same data as for holotype, MNHN-IU -2017 – 1459 (DNA: CA2031 ); 1 ♀, cl 3.6 mm, 12 October 2004, 14°17.738 ′ S 178° 08.423 ʹ W, Vainifao river , Futuna, altitude 150m, G. Marquet, P. Keith & N. Mary coll., MNHN-IU- 2017 – 65 (DNA: CA2033 ) .

Comparative material. Type material

Caridina parvirostris De Man, 1892 .

Syntypes: 2 ♀, cl. 3.1 – 3.2 mm, river near Bombang, Flores Island, Indonesia, M. Weber coll., MNHN-IU-2015-1748; 1 ♀, cl. 4.2 mm, same data as for previous, MNHN-IU-2015- 1754 .

Caridina weberi, 1892 .

Syntypes: 2 ♂, cl 4.4 – 4.5 mm and 1 ♀ ovig, cl 6.1 mm, Kotting , Flores Island, Indonesia, M. Weber coll., MNHN-IU-2015 – 1755.

Description

Cephalothorax. Rostrum ( Figures 3 (h) and 7(F)): always bent down, short, 0.2 – 0.3 of cl, reaching to base of first segment of antennular peduncle, armed dorsally with 5 – 10 teeth, 0 of them on carapace posterior to orbital margin, ventral margin with 0 – 3 teeth. Rostrum formula (0) 5 – 10/0 – 3. Suborbital angle indistinguishably fused with antennal spine. Pterygostomian margin rectangularly rounded.

Eyes well developed, anterior end reaching to 0.73 length of antennular peduncle basal segment. Antennular peduncle 0.47 times as long as carapace. Anterolateral angle reaching 0.20 length of second segment, second segment subequal to third. Stylocerite reaching to 0.90 length of antennular peduncle basal segment. Scaphocerite distincly overreaching tip of antennular peduncle, about 2.1 times longer than wide.

Mouthparts. Left mandible, right mandible, first maxilla, second maxilla, first maxilliped, second maxilliped and third maxilliped typical of genus.

Pereiopods. Epipods on first four pereiopods.

Pereiopod 1 ( Figure 3 (a)): chela about 1.9 – 2.2 times as long as wide, movable finger 2.3 – 2.9 times as long as wide, 0.7 – 1.0 times length of palm, carpus 1.3 – 1.5 times as long as wide.

Pereiopod 2 ( Figure 3 (b)) More slender and longer than first pereiopod with chela 2.4 – 2.6 times as long as wide: movable finger 4.0 – 5.0 times as long as wide, 1.5 – 1.9 times length of palm, carpus slender 5.5 – 6.2 times as long as wide.

Pereiopod 3 ( Figure 3 (c, e)): stout, dactylus 2.6 – 3.9 times as long as wide (terminal spine included) with 5 spines on flexor margin including terminal spine, propodus 8.8 – 13.1 times as long as wide, 3.7 – 4.5 times as long as dactylus.

Pereiopod 5 ( Figure 3 (d, f)): dactylus 2.9 – 3.7 as long as wide with 25 – 38 spiniform setae on flexor margin, propodus 12.2 – 13.8 times as long as wide, 4.3 – 4.9 times as long as dactylus.

Abdomen. Third abdominal somite with moderately convex dorsal profile. Sixth abdominal somite about 0.5 of carapace length, 1.3 times as long as fifth somite, shorter than telson. Telson ( Figure 3 (k)) 2 times as long as wide, with four to six pairs of dorsal spinules and one pair of dorsolateral spinules, posterior margin with median process, rounded with five intermediate plumose setae longer than lateral spines.

First male pleopod: Unknown (no males in the collections).

Second male pleopod: Unknown (no males in the collections).

Preanal carina ( Figure 3 (g)): High, unarmed.

Uropodal diaeresis ( Figure 3 (j)) with 17 – 22 spinules.

Eggs ( Figure 3 (i)): Size 0.43 – 0.53 × 0.25 – 0.30mm.

Habitat ( Figure 7 (g))

This new species prefers fresh and well-oxygenated running waters from the lower course to the higher course.

Etymology

This new species is named futunensis , from the name of the island, Futuna, where this new species occurs.

Colour pattern

Unknown

Distribution ( Figure 8 )

This species is known only from Futuna so far and seems to be endemic.

Remarks

This species looks like C. parvirostris by its bent rostrum with 5 – 10 dorsal teeth and no postorbital teeth (vs bent rostrum with 8 – 10 dorsal teeth and no postorbital teeth in C. parvirostris ) but the P2 carpus is shorter 5.5 – 6.2 times as long as wide (vs 6.0 – 7.4 in C. parvirostris ) and so is P2 chela 2.4 – 2.6 times as long as wide (vs 2.6 – 3.0 in C. parvirostris ). This species differs from C. marquesensis n. sp. and C. tupaia n. sp. by its shorter rostrum 0.2 – 0.3 of cl (vs 0.3 – 0.4 in C. marquesensis n. sp. and C. tupaia n. sp.), fewer dorsal teeth on the rostrum 5 – 10 (vs 10 – 13 in C. marquesensis n. sp. and 8 – 14 in C. tupaia n. sp.) and P5 dactylus with fewer spiniform setae on flexor margin 25 – 38 spines (vs 32 – 55 in C. marquesensis n. sp. and 29 – 54 in C. tupaia n. sp.) and by its telson with five intermediate setae longer than lateral spines (vs 6 – 14 in C. marquesensis n. sp. and 6 – 10 in C. tupaia n. sp.).

This species differs from C. rapaensis by its bent rostrum with more dorsal teeth (5 – 10) (vs bent rostrum with 0 – 5 in C. rapaensis ) and its P5 dactylus ending in two large claws (vs one large claw in C. rapaensis ).

Figures

Figure 3. Caridina futunensis n. sp. Holotype (MNHN-IU-2018-195; DNA: CA2118), (a, b, c) cephalothorax; (d). first pereiopod; e. second pereiopod; (f). third pereiopod; (g). dactylus of third pereiopod; h. fifth pereiopod; i. dactylus of fifth pereiopod; (j). preanal carina; (k). first pleopod; (l). second pleopod.

Figure 7. Live colouration of the species: (a, b). C. tupaia n. sp. (c). C. marquesensis n. sp. (d, e). C. rapaensis. (f). C. futunensis n. sp. (g). Habitat of C. futunensis n. sp. in Futuna. Credits: (a, b, c): G. Marquet; (d, e): E. Vigneux; (f): V. de Mazancourt; (g): A. Dutartre.

Figure 8. Distribution map of the four species studied with oceanic currents of Southern Polynesia (from Martinez et al. 2009) represented: SEC. South Equatorial Current. SECC. South Equatorial Countercurrent. MCC. Marquesas Countercurrent. STCC. South Tropical Countercurrent. GYRE. South Pacific Gyre.