Caridina maeana, 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 : 54-57

Caridina maeana sp. nov.

urn:lsid:zoobank.org:act:36785008-1E93-4AE5-8162-238D2560E30C

Figs 2O , 17 , 26 F–H

Caridina cf. weberi sp. 4 – de Mazancourt et al. 2019a: 166 , 169–170.

Etymology

This new species is named after the local name of the type locality, River Maeana. The name is used as an apposition.

Material examined

Holotype

SOLOMON ISLANDS • ♂, cl 3.6 mm; Malaita Island, Maeana River ; 09°00.056´S, 160°51.893´E; 315 m a.s.l.; 23 Jun. 2015; D. Boseto leg.; DNA voucher: CA1509; MNHN-IU- 2018-2888.

Paratypes

SOLOMON ISLANDS – Malaita Island • 1 ♂, cl 3.1 mm; same collection data as for holotype; MNHN-IU- 2018-2889 • 1 ♂, cl 3.3 mm; same collection data as for holotype; MNHN-IU- 2018-2890 • 1 ♂, cl 3.4 mm; same collection data as for holotype; MNHN-IU- 2018-2891 • 1 ♂, cl 3.5 mm; same collection data as for holotype; MNHN-IU- 2018-2892 • 1 ♂, cl 3.5 mm; same collection data as for holotype; MNHN-IU- 2018-2893 • 1 ♂, cl 4.0 mm; same collection data as for holotype; MNHN- IU- 2018-2894 . – Choiseul Island • 1 specimen; Sicata River ; 07°22.477´S, 157°20.109´E; 46 m a.s.l.; P. Keith, C. Lord, R. Causse and D. Boseto leg.; DNA voucher: CA2495; MNHN • 1 specimen; same collection data as for preceding; DNA voucher: CA2496; MNHN .

Other material

VANUATU • 1 ♀ ovig., cl 5.3 mm; Santo Island , Pelouva River; 14°58.685´S, 166°38.757´E; 279 m a.s.l.; 15 Nov. 2006; P. Gerbeaux, P. Keith and C. Lord leg.; DNA voucher: CA1417; MNHN- IU- 2018-2895 .

Comparative material

Caridina weberi var. keiensis ( Roux, 1911)

INDONESIA • lectotype (selected by Y. Cai, accepted here), ♀ ovig., cl 5.7 mm; Kei Besar, Warka; 5 June 1908; H. Merton leg.; NMB 6 .IV.b • 2 paralectotypes, 2 ♂♂, cl 2.6 mm; same collection data as for lectotype; NMB 6 .IV.a • 2 paralectotypes, 1 ♀, cl 5.5 mm, 1 ♂, cl 3.4 mm; same collection data as for lectotype; NMB 6 .IV.b .

Caridina parvirostris ( De Man, 1892)

INDONESIA • 2 syntypes, ♂♂, cl 3.1–3.2 mm; Flores Island , river near Bombang; Jan. 1889; M. Weber leg.; MHNN-IU-2015-1748 • 1 syntype, ♀, cl 4.2 mm; same collection data as for preceding; MNHN- IU-2015-1754 .

Description

CEPHALOTHORAX. Suborbital angle indistinguishably fused with antennal spine. Pterygostomian margin rounded. Rostrum ( Fig. 17m ): bent down, short, 0.3–0.5 of cl, reaching to base or middle of second segment of antennular peduncle, armed with 8–13 teeth on dorsal margin, all on rostrum considerably anterior to orbital margin, ventral margin with 2–5 teeth. Eyes well developed, anterior end reaching to 0.75 length of basal segment of antennular peduncle. Antennular peduncle 0.70 times as long as carapace. Anterolateral angle reaching 0.20 length of second segment, second segment longer than third segment. Stylocerite reaching to 0.62 length of basal segment of antennular peduncle.

PEREIOPODS. Epipods on first four pereiopods. P1 ( Fig. 17a ): chela about 2.0–2.2 times as long as wide, movable finger 3.1–3.93 times as long as wide, 1.0–1.3 times length of palm; carpus 1.4–1.8 times as long as wide. P2 ( Fig. 17b ) more slender and longer than first pereiopod, with chela 2.3–2.6 times as long as wide: movable finger 4.6–4.9 times as long as wide, 1.6–2.0 times length of palm; carpus slender, 5.0–5.4 times as long as wide. P3 ( Fig. 17c ): stout, dactylus ( Fig. 17e ) 2.4–3.1 times as long as wide (terminal spiniform seta included), with 5–7 spiniform setae on flexor margin in addition to terminal one; propodus 8.6–9.2 times as long as wide, 3.9–5.2 times as long as dactylus. P5 ( Fig. 17d ): dactylus ( Fig. 17e ) 2.4–4.4 times as long as wide, ending in two large claws, with 35–47 spiniform setae on flexor margin; propodus 13.0–17.7 times as long as wide, 4.4–6.0 times as long as dactylus.

ABDOMEN. Third abdominal somite with moderately convex dorsal profile. Sixth abdominal somite 0.49 times as long as carapace, 1.6 times as long as fifth somite, slightly shorter than telson.

TELSON ( Fig. 17i ). 3 times as long as wide, with four or five pairs of dorsal spinules and one pair of dorsolateral spinules; posterior margin with median process, rounded, with 6 very long intermediate setae longer than lateral.

MALE PLEOPODS. Pl1 ( Fig. 17j ): endopod subrectangular, 2.5 times as long as wide, reaching 0.41 lenght of endopod, with appendix on subdistal outer margin which reaches beyond distal end of endopod on short length. Pl2 ( Fig. 17k ): appendix masculina reaching 0.70 times length of endopod; appendix interna reaching 0.64 times length of appendix masculina.

PRE- ANAL CARINA ( Fig. 17g ). High, unarmed.

UROPODAL DIAERESIS ( Fig. 17h ). With 16–19 spinules.

EGGS ( Fig. 17l ). Size: 0.49–0.50 × 0.29–0.30 mm.

Habitat

This new species is largely rheophile and prefers fresh and well-oxygenated waters in the higher course of rivers (279–315 m a.s.l.).

Colour pattern ( Fig. 26F )

The general colour is blueish overall, reddish on the cephalothorax with many red dots all over the body.

Distribution

This species occurs in the Solomon Islands (Malaita and Choiseul) and Vanuatu (Santo Island).

Remarks

This species looks like C. weberi keiensis from Kei Besar Island ( Indonesia) by its rostrum with 8–13 dorsal teeth (vs 2–13 in C. w. keiensis), all of them on the rostrum, considerably anterior to the orbital margin, and its P5 dactylus ending in two large claws. However, the P2 dactylus is longer, 4.6–4.9 times as long as wide (vs 3.2–4.1), as is the P2 carpus, 5.0–5.4 (vs 3.5–4.5).

This species also looks like C. parvirostris ( De Man, 1892) from Flores (Indonesia) by its rostrum with 8–13 dorsal teeth (vs 8–10 in C. parvirostris ), but the P2 carpus is shorter, 5.0–5.4 times as long as wide (vs 6.0–7.4), as is the P2 chela, 2.3–2.6 (vs 2.6–3.0), and its P5 ends in two large claws (vs one claw).

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. 17. Caridina maeana 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-2018-2889: (a–i, m), MNHN-IU-2018-2891 (j–k) and MNHN-IU-2018-2895 (l).

Fig. 26. Live colourations. A. Caridina buehleri Roux, 1934 (MNHN-IU-2015-20). B. Caridina gueryi Marquet, Keith & Kalfatak, 2009 (MNHN-IU-2015-19). C. Caridina weberi De Man, 1892 (Kolombangara Island). D. Caridina serratirostris De Man, 1892 (MNHN-IU-2018-2931). E. Caridina papuana Nobili, 1905 (Choiseul Island). Habitats in the Solomon Islands. F. Caridina maeana sp. nov. (Choiseul Island). G. Lentic mode, Lodumoe river, Kolombangara Island. H. Lotic mode, Sulumuni river, Kolombangara Island. Photopgraphs by P. Keith (A, D–F, H) and C. Lord (B–C, G).