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 Author Mazancourt, Valentin de 334E54F3-9FE1-4208-8861-1946579697A5 Unité Biologie des organismes et écosystèmes aquatiques (BOREA), Muséum national d’Histoire naturelle, Sorbonne Université, Université de Caen Normandie, Université des Antilles, CNRS, IRD, CP 26, 57 rue Cuvier 75005 Paris, France. Museum f ̹ r Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstrasse 43, 10115 Berlin, Germany. Ecological Solutions in Solomon Islands, Western province, Gizo, Solomon Islands. valentin.demazancourt@laposte.net Author Boseto, David E2AA5328-9578-4380-9254-3FA0B65807E6 Ecological Solutions in Solomon Islands, Western province, Gizo, Solomon Islands. dboseto@ecologicalsolutions-si.com Author Marquet, Gerard BB110358-4FA2-4F5B-BF3A-B51F69D81AA9 Unité Biologie des organismes et écosystèmes aquatiques (BOREA), Muséum national d’Histoire naturelle, Sorbonne Université, Université de Caen Normandie, Université des Antilles, CNRS, IRD, CP 26, 57 rue Cuvier 75005 Paris, France. Museum f ̹ r Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstrasse 43, 10115 Berlin, Germany. Ecological Solutions in Solomon Islands, Western province, Gizo, Solomon Islands. gmarquet@neuf.fr Author Keith, Philippe FDDE84AB-E459-401C-A9BF-3F16CEEBFD7C Unité Biologie des organismes et écosystèmes aquatiques (BOREA), Muséum national d’Histoire naturelle, Sorbonne Université, Université de Caen Normandie, Université des Antilles, CNRS, IRD, CP 26, 57 rue Cuvier 75005 Paris, France. Museum f ̹ r Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstrasse 43, 10115 Berlin, Germany. Ecological Solutions in Solomon Islands, Western province, Gizo, Solomon Islands. keith@mnhn.fr text European Journal of Taxonomy 2020 2020-08-04 696 1 86 journal article 21373 10.5852/ejt.2020.696 5e1d0e63-c052-42fa-ba84-55f2166bfefd 3973435 265EDD08-7AA8-4835-B7F6-353E7992633E 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). 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). 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).