Caridina neglecta Cai & Ng, 2007

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 : 14-17

Caridina neglecta Cai & Ng, 2007

Figs 2F , 5 , 25B

Caridina neglecta Cai & Ng, 2007: 1595 , figs 4–5 (type locality: Sungai Batang, 13 km on road from Palopo to Wotu, Sulawesi, Indonesia).

Material examined

Holotype

INDONESIA • ♂, cl 4.3 mm; Sulawesi, Sungai Batang, 13 km on road from Palopo to Wotu ; Mar. 1989; M. Kottelat and A. Werner leg.; MZB Cru 1570.

Paratype

INDONESIA • 1 ♀, cl 4.4 mm; same collection data as for holotype; ZRC 2007.0096 .

Other material

SOLOMON ISLANDS – Choiseul Island • 1 ♂, cl 4.5 mm; Lokasereke River ; 06°58.024´S, 156°47.861´E; 45 m a.s.l.; 13 Oct. 2014; P. Gerbeaux, P. Keith and G. Marquet leg.; DNA voucher: CA1310; MNHN-IU- 2018-2808 . – Kolombangara Island • 1 ♀ ovig., cl 4.2 mm; Liva River ; 08°03.863´S, 157°10.633´E; 18 m a.s.l.; 11 Nov. 2015; P. Keith, C. Lord and G. Marquet leg.; MNHN- IU-2019-106 • 1 ♂, cl 3.1 mm; same collection data as for preceding; MNHN-IU-2019-105 • 1 ♀ ovig., cl 5.0 mm; Jack Harbour River ; 08°03.085´S, 157°10.945´E; 11 m a.s.l; 11 Nov. 2015; P. Keith, C. Lord and G. Marquet leg.; MNHN-IU- 2018-2811 • 1 ♀ ovig., cl 4.7mm; Vanga 2 River ; 07°54.825´S, 156°57.762´E; 17 m a.s.l.; 18 Nov. 2015; P. Keith, C. Lord and G. Marquet leg.; MNHN-IU- 2018-2812 . – Vella Lavella Island • 1 ♀ ovig., cl 4.9 mm; Vala Kadju River ; 07°49.860´S, 156°42.644´E; 17 m a.s.l.; 28 Oct. 2016; P. Keith and C. Lord leg.; DNA voucher: CA1703; MNHN-IU- 2018-2813 • 1 ♀, cl 4.1 mm; Joroveto River ; 07°49.918´S, 156°42.887´E; 18 m a.s.l.; 28 Oct. 2016; P. Keith and C. Lord leg.; MNHN-IU- 2018-2814 .

VANUATU – Santo Island • 1 ♀ ovig., cl 5.6 mm; Sarataka River ; 15°30.078´S, 167°09.261´E; 25 Jul. 2003; D. Kalfatak, P. Keith and G. Marquet leg.; MNHN-IU-2015-1767 . – Isabel Island • 1 specimen; Kolopakissa, Fufuna River ; 07.64456° S, 158.71918° E; 15 m a.s.l.; 25 Oct. 2019; P. Keith, C. Lord, R. Causse and D. Boseto leg.; DNA voucher: CA2504; MNHN • 1 specimen; same collection data as for preceding; DNA voucher: CA2505; MNHN • 1 specimen; Rakata River confluence; 07.64190° S, 158.71504° E; 27 Oct. 2019; P. Keith, C. Lord, R. Causse and D. Boseto leg.; DNA voucher: CA2513; MNHN .

Description

CEPHALOTHORAX. Antennal spine short, situated below inferior orbital angle. Pterygostomian margin rectangular round. Rostrum ( Fig. 5m ): strongly upturned, very long, 1.6–2.2 of cl, reaching far beyond distal end of scaphocerite, armed with 5–9 teeth on dorsal margin, with 1–2 apical teeth, non of them situated on carapace behind orbital margin, ventral margin with 21–27 teeth. Eyes well developed, anterior end reaching to 0.7 times length of basal segment of antennular peduncle. Antennular peduncle 0.69 (♀) – 0.88 (♂) times as long as carapace. Anterolateral angle reaching 0.32 length of second segment, second segment distinctly longer than third segment. Stylocerite reaching to 0.86 length of basal segment of antennular peduncle.

PEREIOPODS. Epipods on first four pereiopods. P1 ( Fig. 5a ): chela about 2.2–2.5 times as long as wide, movable finger 3.2–4.2 times as long as wide, 1.1–1.5 times length of palm; carpus 2.3–3.1 times as long as wide. P2 ( Fig. 5b ) more slender and longer than first pereiopod, with chela 2.5–3.1 times as long as wide; movable finger 3.7–4.9 times as long as wide, 1.2–1.6 times length of palm; carpus slender, 5.2–6.4 times as long as wide. P3 ( Fig. 5c ): stout, dactylus ( Fig. 5e ) 3.3–4.7 times as long as wide (terminal spiniform seta included), with 5–7 spiniform setae on flexor margin in addition to the terminal one; propodus 11.8–17.3 times as long as wide, 4.1–5.4 times as long as dactylus. P5 ( Fig. 5d ): dactylus ( Fig. 5f ) 4.0–5.3 as long as wide, with 31–53 spinifrom setae on flexor margin; propodus 12.9–21.1 times as long as wide, 3.7–4.5 times as long as dactylus.

ABDOMEN. Third abdominal somite with moderately convex dorsal profile. Sixth abdominal somite 0.80 as long as carapace, 1.76 times as long as fifth somite, slightly shorter than telson.

TELSON ( Fig. 5i ). 3.4–3.7 times as long as wide, with three or four pairs of dorsal spinules and one pair of dorsolateral spinules; posterior margin with a median process, distal setae short, lateral pair slightly longer than intermediate setae (mostly two pairs).

MALE PLEOPODS. Pl1 ( Fig. 5j ): endopod subtriangular, 1.5 times as long as wide, 0.17 times as long as exopod, with an appendix interna, on the subdistal outer margin, which reaches beyond distal end of endopod by a short length. Pl2 ( Fig. 5k ): appendix masculina reaching 0.57 times length of endopod; appendix interna reaching 0.71 of appendix masculina.

PRE- ANAL CARINA ( Fig. 5g ). With a spine.

UROPODAL DIAERESIS ( Fig. 5h ). With 7–10 spinules.

EGGS ( Fig. 5l ). Size: 0.40–0.53 × 0.24–0.30 mm.

Habitat

In the lower course of streams, near the estuary.

Colour pattern ( Fig. 25B )

Totally translucent body with a characteristic red ventral margin on the rostrum.

Distribution

This species occurs in Indonesia, the Philippines, the Solomon Islands and Vanuatu.

Remarks

Our specimens fit well with the description given by Cai & Ng (2007): rostrum very long, reaching far beyond distal end of scaphocerite, strongly upturned, with presence of 0 postorbital teeth (vs 0 in Cai & Ng (2007)), 5–9 dorsal teeth (vs 4–8) and 21–27 ventral teeth (vs 21–30); P1 carpus 2.3–3.1 times as long as wide (vs 2.3–2.9); P2 carpus 5.2–6.4 times as long as wide (vs 6.2–6.7). P3 dactylus with 5–7 spiniform setae (vs 6), propodus 4.1–5.4 as long as dactylus (vs 4.1–5.1); P5 dactylus with about 31–53 spiniform setae (vs 37–44) and propodus 3.7–4.5 times as long as dactylus (vs 3.7–3.8); uropodal diaresis 7–10 (vs 9); small eggs 0.40–0.51 × 0.24–0.30 mm (vs 0.40 × 0.25 mm); appendix interna on the endopod of the male first pleopod.

The presence of an appendix interna on the endopod of the male first pleopod (vs no appendix interna) and a longer P1 carpus, 2.3–3.1 times as long as wide (vs 1.5–1.9), and P2 carpus, 5.2–6.4 times as long as wide (vs 3.2–5.1), separates C. neglecta from C. gracilirostris .

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. 5. Caridina neglecta Cai & Ng, 2007. 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-2018-2811 (a–i, l) and MNHN-IU-2018-2808 (j–k, m).

Fig. 25. Live colourations.A. Caridina gracilirostris De Man, 1892 (MNHN-IU-2018-2804).B. Caridina neglecta Cai & Ng, 2007 (MNHN-IU-2018-2811). C. Caridina appendiculata Jalihal & Shenoy, 1998 (MNHN-IU-2018-135). D. Caridina brevidactyla Roux, 1919 (CA1503). E. Caridina choiseul sp. nov. (Choiseul Island). F. Caridina intermedia sp. nov. (MNHN-IU-2014-20847). G. Caridina mertoni Roux, 1911 (Kolombangara Island). Photographs by P. Keith (A–G).