Caridina barakoma, 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 : 8-11

Caridina barakoma sp. nov.

urn:lsid:zoobank.org:act:E0FB6A6C-EDA8-4667-81F4-695A9632658D

Figs 2G , 3

Caridina brevicarpalis – Page et al., 2007: 649 (GenBank: DQ478485 ). — de Mazancourt et al. 2019a: 166, 169–170.

Etymology

This new species in named after the village near the type locality. The name is used as an apposition.

Material examined

Holotype

SOLOMON ISLANDS • ♂, cl 3.7 mm; Vella Lavella Island , Vala Kadju River; 07°49.860´S, 156°42.644´E; 18 m a.s.l.; 28 Oct. 2016; P. Keith and C. Lord leg.; MNHN-IU-2014-20805.

Paratypes

SOLOMON ISLANDS – Vella Lavella Island • 1 ♂, cl 2.7 mm; same collection data as for holotype; DNA voucher: CA1942; MNHN-IU-2014-20810. – Choiseul Island • 1 ♀ ovig., cl 5.6 mm; Turipi River ; 07°00.661´S, 156°49.075´E; 50 m a.s.l.; 15 Sep. 2014; P. Keith, G. Marquet and M. Mennesson leg.; MNHN-IU-2014-20806 • 1 ♀ ovig., cl 5.6 mm; Lopakare River downstream; 07°01.834´S, 156°45.789´E; 14 m a.s.l.; 21 Sep. 2014; P. Gerbeaux, P. Keith and G. Marquet leg; DNA voucher: CA1364; MNHN-IU-2014-20807 • 1 ♀ ovig., cl 5.8 mm; same collection data as for preceding; MNHN- IU-2014-20808. – Kolombangara Island • 1 ♀, cl 3.6 mm; Vagé River ; 08°05.112´S, 156°59.867´E; 10 Nov. 2015; 21 m a.s.l.; P. Keith, C. Lord and G. Marquet leg.; DNA voucher: CA1521; MNHN- IU-2014-20809. – Isabel Island • 1 specimen; Suavanao, Rakata River ; 15 m a.s.l.; 07.64456° S, 158.71918° E; 27 Oct. 2019; P. Keith, C. Lord, R. Causse and D. Boseto leg.; DNA voucher: CA2511; MNHN • 1 specimen; same collection data as for preceding; DNA voucher: CA2512; MNHN • 1 specimen; same collection data as for preceding; DNA voucher: CA2515; MNHN • 1 specimen; same collection data as for preceding; DNA voucher: CA2516; MNHN .

INDONESIA • 1 ♀ ovig., cl 7.0 mm; West Papua, Kayumera , found in a fish’s gut content; 03°53.525´S, 134°28.621´E; 22 Oct. 2010; P. Keith leg.; MNHN-IU-2014-20820 .

PAPUA NEW GUINEA – New Britain Island • 1 ♀ ovig., cl 5.1 mm; Wara Creek ; 05°38.843´S, 150°39.012´E; 29 Oct. 2018; R. Causse, P. Keith and C. Lord leg.; MNHN-IU-2014-20811 • 1 ♀ ovig., cl 6.6mm; same collection data as for preceding; MNHN-IU-2014-20812 • 1 ♀, cl 6.1 mm; same collection data as for preceding; MNHN-IU-2014-20813 • 1 ♀ ovig., cl 5.4 mm; Walindi Creek ; 05°21.187´S, 150°02.693´E; 30 Oct. 2018; R. Causse, P. Keith and C. Lord leg.; MNHN-IU-2014-20814 • 1 ♀ ovig., cl 5.6mm; same collection data as for preceding; MNHN-IU-2014-20815 • 1 ♀ ovig., cl 5.3 mm; Vaavu River ; 05°22.584´S, 150°03.724´E; 30 Oct. 2018; R. Causse, P. Keith and C. Lord leg.; MNHN- IU-2014-20816 • 1 ♀ ovig., cl 5.9 mm; same collection data as for preceding; MNHN-IU-2014-20817 • 1 ♀ ovig., cl 6.2 mm; Crusher ; 05°38.603´S, 150°10.957´E; 31 Oct. 2018; R. Causse, P. Keith and C. Lord leg.; MNHN-IU-2014-20818 • 1 ♀ ovig., cl 6.5 mm; same collection data as for preceding; MNHN-IU-2014-20819 .

Description

CEPHALOTHORAX. Antennal spine below suborbital angle. Pterygostomian margin sub rectangular. Rostrum ( Fig. 3m ) long, 0.9–1.2 of cl, passing end of scaphocerite, armed with 12–16 teeth on dorsal margin, without apical teeth, 0–1 of them situated on carapace behind orbital margin, ventral margin with 5–10 teeth. Eyes well developed, anterior end reaching to 0.50–0.60 length of basal segment of antennular peduncle. Antennular peduncle 0.72 (♀) or 0.88 (♂) times as long as carapace. Anterolateral angle reaching 0.20 length of second segment, basal segment of antennular peduncle longer than sum of second and third segment lengths, second segment distinctly longer than third segment. Stylocerite reaching 0.75–0.78 length of basal segment of antennular peduncle.

PEREIOPODS. Epipods on first four pereiopods. P1 ( Fig. 3a ): chela about 1.9–2.1 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 1.1–1.6 times as long as wide. P2 ( Fig. 3b ) more slender and longer than first pereiopod, with chela 1.8–2.1 times as long as wide: movable finger 3.1–3.8 times as long as wide, 1.2–1.3 times length of palm; carpus stout 2.8–3.7 times as long as wide. P3 ( Fig. 3c ): stout, very short dactylus ( Fig. 3e ) 2.1–2.8 times as long as wide (terminal spiniform seta included) with 5–6 spiniform setae on flexor margin including terminal one; short propodus 2.1–2.8 times as long as wide, 4.3–5.4 times as long as dactylus. P5 ( Fig. 3d ): dactylus ( Fig. 3f ) very short, 2.0–2.5 as long as wide with 6–17 spiniform setae on flexor margin; propodus 2.0–2.5 times as long as wide, 5.1–9.0 times as long as dactylus.

ABDOMEN. Third abdominal somite with moderarely convex dorsal profile. Sixth abdominal somite 0.58 times cl, 1.6 times as long as fifth somite, shorter than telson.

TELSON ( Fig. 3h ). 3.2–3.4 times as long as wide, with four to six pairs of dorsal spinules and one pair of dorsolateral spinules; posterior margin with a median process, it is rounded with 4 intermediate setae shorter than lateral ones.

MALE PLEOPODS. Pl1 ( Fig. 3j ): endopod subtriangular, 2.3 times as long as wide, reaching 0.29–0.41 length of exopod, with an appendix on subdistal outer margin which reaches beyond distal end of endopod with most of its length. Pl2 ( Fig. 3k ): appendix masculina reaching 0.54–0.56 times length of endopod; appendix interna reaching 0.77 of appendix masculina.

PRE- ANAL CARINA ( Fig. 3g ). High, armed with a spine.

UROPODAL DIAERESIS ( Fig. 3h ). With 8–10 spinules.

EGGS ( Fig. 3l ). Size: 0.21–0.25 × 0.37–0.40 mm.

Habitat

In the vegetation at the edge of the rivers in flowing water in the lower course of rivers.

Colour pattern

Unknown.

Distribution

Only collected in the Solomon Islands (Choiseul, Kolombangara, Vella Lavella, Isabel and Guadalcanal).

Remarks

This new species looks like the type specimens of C. brevicarpalis and C. endehensis both described by De Man (1892), with their very long rostrum, passing the end of the scaphocerite, without apical tooth and its P1 carpus deeply excavated. It can, however, easily be distinguished from C. brevicarpalis by its rostrum armed with more teeth on the dorsal margin, 12–16 (vs 11–14 for C. brevicarpalis ) and on the ventral margin 5–10 teeth (vs 4–7), by its P3 propodus 4.3–5.4 times as long as dactylus (vs 4), by its P5 dactylus with fewer spiniform setae on flexor margin 6–17 (vs 20) and by its P5 propodus 5.1–9.0 times as long as dactylus (vs 5). Egg sizes are smaller, 0.21–0.25 × 0.37–0.40 (vs 0.33 × 0.53 according to Bouvier 1925). From C. endehensis , it can easily be separated by its rostrum slightly overreaching the antennal peduncle (vs far overreaching antennal scale for C. endehensis ), dorsal margin nearly horizontal (vs ascendant in anterior ½), armed with 12–16 teeth on posterior ¾ (vs 9–23 in posterior ½), armed ventrally with 5–10 teeth (vs 4–24).

In the litterature on C. brevicarpalis , we only find 3 drawings: in De Man (1892), Bouvier (1925) and Edmondson (1935). The latter studied specimens from Viti Levu ( Fiji) which seem different from our species by their rostrum armed with 18 teeth on the dorsal margin and 7 on the ventral margin (vs respectively 12–16 and 5–10 in C. barakoma sp. nov. and 11–14 and 4–7 in the type specimens of C. brevicarpalis ). By their uropodal diaeresis, 10–13, it also seems different from our new species (8–10) and the type specimens (8–9 according Bouvier 1925). Fiji is the easternmost limit of the C. brevicarpalis complex in the Pacific, as no species of this group occur in Futuna, Samoa or French Polynesia ( Keith et al. 2013). In this paper we postulate that the C. brevicarpalis group includes several different species allied to C. brevicarpalis like C. barakoma sp. nov., C. endehensis and the Fijian species.

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. 3. Caridina barakoma sp. nov. a. First pereiopod. b. Second pereiopod. c. Third pereiopod. d. Fifth pereiopod. e. Dactylus of third pereiopod. f. Dactylus of fifth pereiopod. g. Pre-anal carina. h. Uropodal diaeresis. i. Telson. j. First male pleopod. k. Second male pleopod. l. Eggs. m. Cephalothorax. MNHN- IU-2014-20807 (a–i, l–m) and MNHN-IU-2014-20805 (j–k).