Caridina sikipozo, Mazancourt & Boseto & Marquet & Keith, 2020

Mazancourt, Valentin de, Boseto, David, Marquet, Gerard & Keith, Philippe, 2020, Solomon’s Gold Mine: Description or redescription of 24 species of Caridina (Crustacea: Decapoda: Atyidae) freshwater shrimps from the Solomon Islands, including 11 new species, European Journal of Taxonomy 696, pp. 1-86 : 62-64

Caridina sikipozo sp. nov.

urn:lsid:zoobank.org:act:6A7B9C82-DA70-47AA-81C4-21C351A7BD4F

Figs 2V , 20

Etymology

This species is named after the Sikipozo tribe living around the type locality.

Material examined

Holotype

SOLOMON ISLANDS • ♂, cl 3.2 mm; Choiseul Island, Lokataveva Creek ; 06°59.085´S, 156°47.454´E; 93 m a.s.l.; 14 Oct. 2014; P. Gerbeaux, P. Keith and G. Marquet leg.; DNA voucher: CA1928; MNHN- IU- 2018-2914.

Paratype

SOLOMON ISLANDS • 1 ♂, cl 3.1 mm; same collection data as for holotype; DNA voucher: CA2310; MNHN-IU- 2018-2915 .

Description

CEPHALOTHORAX. Suborbital angle indistinguishably fused with antennal spine. Rostrum ( Fig. 20j ): bent down, short, 0.3–0.4 of cl, reaching end of first segment of antennular peduncle, armed with 14–17 teeth on dorsal margin, 2–3 of them situated on carapace behind orbital margin, ventral margin with 4–5 teeth. Eyes well developed, anterior end reaching to 0.70 length of basal segment of antennular peduncle. Antennular peduncle 0.63 (♂) times as long as carapace. Pointed anterolateral angle reaching 0.31 length of second segment, second segment longer than third segment. Stylocerite reaching to 0.94 length of basal segment of antennular peduncle.

PEREIOPODS. Epipods on first four pereiopods. P1 ( Fig. 20a ): chela about 2.1–2.2 times as long as wide, movable finger 3.4–3.5 times as long as wide, 1.1–1.3 times length of palm; carpus 1.7–1.8 times as long as wide. P2 ( Fig. 20b ) more slender and longer than first pereiopod, with chela 2.3–2.4 times as long as wide: movable finger 4.7–4.8 times as long as wide, 1.6–1.8 times length of palm; short carpus, 5.2–5.3 times as long as wide. P3 ( Fig. 20c ): stout, dactylus ( Fig. 20d ) 3.2 times as long as wide (terminal spiniform seta included), with 6 spiniform setae on flexor margin including terminal one; propodus 10.3–11.3 times as long as wide, 4.3–4.4 times as long as dactylus. P5: missing in all specimens.

ABDOMEN. Third abdominal somite with moderately convex dorsal profile. Sixth abdominal somite 0.48 times as long as carapace, 1.7 times as long as fifth somite, 0.86 times as long as telson.

TELSON ( Fig. 20g ). 2.3 times as long as wide, eight pairs of dorsal spinules and pair of dorsolateral spinules; posterior margin without median process, rounded, with 6–9 long intermediate setae longer than lateral ones.

MALE PLEOPODS. Pl1 ( Fig. 20h ): endopod subrectangular, 3 times as long as wide, reaching 0.53 lenght of endopod, with an appendix on subdistal outer margin which reaches beyond distal end of endopod on a short length. Pl2 ( Fig. 20i ): appendix masculina reaching 0.72 times length of endopod; appendix interna reaching 0.61 lenght of appendix masculina.

PRE- ANAL CARINA ( Fig. 20e ). High, unarmed.

UROPODAL DIAERESIS ( Fig. 20f ). With 23 spinules.

Habitat

This new species is largely rheophile and prefers fresh and well-oxygenated waters in the higher course of rivers.

Colour pattern

Unknown.

Distribution

As far as we know, this new species occurs only on Choiseul ( Solomon Islands).

Remarks

These specimens from the Solomon Islands are very similar to Caridina turipi sp. nov. by the high number of postorbital teeth on the dorsal margin of the rostrum (2–3 vs 2–4 for C. turipi sp. nov.). However, this new species can be separated by its longer P1 dactylus (3.4–3.5 vs 2.8–3.0 mm), by its shorter P2 chela (2.3–2.4 vs 2.6–3.1 mm) and shorter P2 carpus (5.2–5.3 vs 5.5–6.6 mm).

Figures

Fig. 2. Bayesian inference phylogenetic tree of the species studied. Numbers above branches are Bayesian posterior probabilities, numbers under branches are Maximum Likelihood bootstrap values. Results of the three species delimitation methods are indicated by the black bars on the right of the tree. Each bar represents a species recognized by the analysis.

Fig. 20. Caridina sikipozo sp. nov. a. First pereiopod. b. Second pereiopod. c. Third pereiopod. d. Dactylus of third pereiopod. e. Pre-anal carina. f. Uropodal diaeresis. g. Telson. h. First male pleopod. i. Second male pleopod. j. Cephalothorax. MNHN-IU-2018-2914 (a–e, g, j) and MNHN-IU-2018-2915 (f, h–i).