Caridina longicarpus Roux, 1926

Mazancourt, Valentin de, Bréthiot, Julien, Marquet, Gérard & Keith, Philippe, 2022, West Side Story: A molecular and morphological study of Caridina longicarpus Roux, 1926 (Decapoda, Caridea, Atyidae) from New Caledonia reveals a new species, Zoosystema 44 (18), pp. 463-474 : 466-469

Caridina longicarpus Roux, 1926

( Figs 2 ; 3 )

Caridina weberi var. longicarpus Roux, 1926: 212 , figs 37-39.

Caridina weberi longicarpus – Holthuis 1969: 103.

Caridina longicarpus – de Mazancourt et al. 2019a: 166 (part: CA1557 and CA1599), figs 2-5.

Non Caridina weberi – Marquet et al. 2002 (part); 2003: 72 (part). — Choy & Marquet 2002: 220, 209 (part). — Taillebois et al. 2013: 106.

TYPE MATERIAL. — Lectotype (here designated among the syntypes). New Caledonia • 1♂ cl 4.1 mm; above Oubatche, slopes of Mt. Ignambi ; 600 m a.s.l.; IV.1911; F. Sarasin & J. Roux leg.; NMB 6.V.a.

Paralectotypes. New Caledonia • 1♂ cl 3.4 mm and 1♀ ovig. cl. 5.7 mm; same data as for lectotype • 1♀ cl 4.7 mm; Ciu , above Canala; 300 m a.s.l.; X.1911; F. Sarasin & J. Roux leg.; NMB 6 . V.b .

OTHER MATERIAL EXAMINED. — New Caledonia • 1♀ ovig.cl 5.3 mm; Wewec river ; 20°37.506’S, 164°44.637’E; 15.X.2010, G. Marquet & L. Taillebois leg.; DNA: CA1558 ; MNHN-IU-2018-3323 • 1♀ ovig. cl 5.8 mm; same collection data as preceding; MNHN- IU-2018-3383 • 1♀ cl 4.7 mm; same collection data as preceding; DNA: CA1557 ; MNHN-IU-2018-3322 • 1♀ cl 5.9 mm; same collection data as preceding; DNA: CA1642 ; MNHN-IU-2018-3330 • 1♀ cl 3.5 mm; same collection data as preceding; DNA: CA1647 ; MNHN-IU-2018-3334 • 1♀ cl 4.2 mm; same collection data as preceding; DNA: CA1643 ; MNHN-IU-2018-3331 • 1♂ cl 4.2 mm; same collection data as preceding; DNA: CA1640 ; MNHN-IU-2018-3328 • 1♂ cl 4.6 mm; same collection data as preceding; DNA: CA1641 ; MNHN-IU-2018-3329 • 1♂ cl 4.0 mm; same collection data as preceding; DNA: CA1644 ; MNHN- IU-2018-3332 • 1♂ cl 3.9 mm (MNHN-IU-2018-3333, DNA: CA1646 ), 1♂ cl 3.4 mm; same collection data as preceding; DNA: CA1648 ; MNHN-IU-2018-3335 • 1♀ ovig. cl 6.9 mm; Coula river ; 21°21.656’S, 165°20.370’E; 240 m a.s.l.; 26.IX.2016; V. de Mazancourt, P. Tiberghien & G. Marquet leg.; DNA: CA1594 ; MNHN-IU-2018-3324 • 1♀ ovig. cl 7.3 mm; same collection data as preceding; DNA: CA1595 ; MNHN-IU-2018-3325 • 1♀ ovig. cl 6.9 mm; same collection data as preceding; DNA: CA1649 ; MNHN-IU-2018-3336 • 1♀ ovig. cl 5.4 mm; same collection data as preceding; DNA: CA1650 ; MNHN-IU-2018-3337 • 1♀ ovig. cl 5.9 mm; same collection data as preceding; DNA: CA1651 ; MNHN-IU-2018-3338 • 1♀ cl 5.0 mm; same collection data as preceding; DNA: CA1652 ; MNHN-IU-2018-3339 • 1♂ cl 4.0 mm; same collection data as preceding; DNA: CA1599 ; MNHN-IU-2018-3326 • 1♂ cl 3.7 mm; same collection data as preceding; DNA: CA1600 ; MNHN-IU-2018-3327 • 1♂ cl 3.4 mm; same collection data as preceding; DNA: CA1653 ; MNHN- IU-2018-3340 • 1♂ cl 3.9 mm; same collection data as preceding; DNA: CA1654 ; MNHN-IU-2018-3341 • 1♂ cl 3.9 mm; same collection data as preceding; DNA: CA1655 ; MNHN-IU-2018-3342 • 1♀ ovig. cl 4.9 mm; Creek Waxac ( HYNC742 ); 20°39.789’S, 164°44.762’E; 310 m a.s.l.; 14.XI.2016; V. de Mazancourt leg.; DNA: CA1659 ; MNHN-IU-2018-3343 • 1♀ ovig. cl 6.3 mm; Diahot river ( HYNC707 ); 20°31.285’S, 164°33.113’E; 100 m a.s.l.; 5.XI.2016; C. Pöllabauer, C. Huet & N. Charpin leg.; DNA: CA1879 ; MNHN-IU-2018-3344 • 1♀ cl 6.0 mm; same collection data as preceding; DNA: CA1880 ; MNHN-IU-2018-3345 • 1♀ cl 5.0 mm; same collection data as preceding; DNA: CA1881 ; MNHN-IU-2018-3346 • 1♀ cl 6.4 mm; same collection data as preceding; DNA: CA1882 ; MNHN-IU-2018-3347 .

COMPARATIVE MATERIAL. — Caridina weberi De Man, 1892 : Syntypes: Indonesia • 1♂ cl 4.5 mm, 1♀ ovig. cl 6.1 mm, 1♂ cl 4.4 mm; Kotting , Flores Island; XII.1888; M. Weber leg.; MNHN- IU-2015-1755.

Caridina parvirostris De Man, 1892 : Syntypes: Indonesia • 2♂ cl 3.1-3.2 mm, 1♀ cl 4.2 mm; river near Bombang , Flores Island; I.1889; M. Weber leg.; MNHN-IU-2015-1748 .

HABITAT. — This species is largely rheophile and prefers fresh and well-oxygenated waters from the middle to the higher courses (100- 600 m) ( Fig. 3D ).

COLOUR PATTERN. — Variable, body dark brown or blue with sometimes a white dorsal line stretching from the rostrum to the telson and numerous reddish-brown spots all over the body ( Fig. 3 A-C).

DISTRIBUTION. — This species has been collected only in New Caledonia so far and seems endemic. It is only found in the rivers flowing to the East coast ( Fig. 6 ).

DESCRIPTION

Cephalothorax

Suborbital angle indistinguishably fused with antennal spine. Pterygostomian margin rounded. Rostrum ( Fig. 2M, N ): bent, short, 0.2-0.6 of cl; 0.3-0.4, mean 0.39 (n = 28) reaching from base to slightly beyond middle of second segment of antennular peduncle, armed with 10-24 teeth on dorsal margin (mean 16, n = 27), 0-2 of them situated on carapace behind orbital margin (mean 0), ventral margin with 1-11 teeth (mean 4, n = 26).

Cephalic appendages

Eyes well developed, anterior end reaching to 0.55 length of basal segment of antennular peduncle. Antennular peduncle 0.49(♀)-0.57(♂) times as long as carapace. Anterolateral angle reaching 0.30 length of the second segment, second segment same length as the third. Stylocerite reaching just before the tip of the basal segment of antennular peduncle.

Pereiopods

Epipods on first four pereiopods. P1 ( Fig. 2A ): chela about 2.0-2.5 times as long as wide, movable finger 2.7-3.9 times as long as wide, 1.0-2.0 times length of palm; carpus 1.7-2.2 times as long as wide. P2 ( Fig. 2B ) more slender and longer than P1 with chela 2.2-3.2 times as long as wide:movable finger 4.0-5.4 times as long as wide, 1.4-1.9 times length of palm; carpus slender 5.0-7.4 times as long as wide. P3 ( Fig. 2C ): stout, dactylus ( Fig. 2E ) 2.6-3.4 times as long as wide (terminal spiniform seta included) with 5-8 spiniform setae on flexor margin in addition to the terminal spiniform seta; propodus 8.7-14.6 times as long as wide, 3.8-6.0 times as long as dactylus. P5 ( Fig. 2D ): dactylus ( Fig. 2F ) 3.3-4.9 times as long as wide with 27-72 spiniform setae on flexor margin (52, n = 17); propodus 11.9-18.2 times as long as wide, 4.1-5.4 times as long as dactylus (mean 4.5, n = 18).

Abdomen

Third abdominal somite with moderately convex dorsal profile. Sixth abdominal somite about half of carapace length, 1.2 times as long as fifth somite, reaching 0.8 times length of telson.

Telson ( Fig. 2G )

2.7 times as long as wide, with 5-8 pairs of dorsal spinules and one pair of dorsolateral spinules; posterior margin with a median process, rounded with 5-10 (mean 7, n = 21) very long intermediate setae longer than lateral ones.

Pl1 ( Fig. 2J )

Endopod of male subrectangular, 2.3 times as long as wide, reaching 0.37 times of exopod, with an appendix on the subdistal outer margin which reaches beyond distal end of endopod on a short length.

Pl2 ( Fig. 2K )

Appendix masculina on second pleopod reaching 0.50 times length of endopod; appendix interna reaching 0.50 of appendix masculina.

Preanal carina ( Fig. 2I )

High, unarmed.

Uropodal diaeresis ( Fig. 2H )

With 17-23 spinules.

Eggs ( Fig. 2L )

0.41-0.52 × 0.24-0.32 mm.

REMARKS

According to Roux (1926), C. longicarpus looks like C. parvirostris De Man, 1892 by its downward bent rostrum and its long P2 carpus 5.0-7.4 times as long as wide (vs 6.0- 7.4 in C. parvirostris ) but the rostrum bears more teeth 10-24 (vs 8-10 in C. parvirostris ) like C. weberi De Man, 1892 (vs 11-15 in C. weberi ). But this latter species has a shorter P2 carpus 4.9-5.4 (vs 5.0- 7.4 in C. weberi ).

Our specimens fit well with the types described by Roux (1926) from New Caledonia: a short bent rostrum, 0.2-0.5 of cl (vs 0.2-0.4), armed with 10-24 teeth on dorsal margin (vs 13-25), 0-2 of them situated on carapace behind orbital margin (vs 0-2); ventral margin with 1-11 teeth (vs 3-7); P1 carpus 1.7-2.2 times as long as wide (vs. 1.5-1.9) and P2 carpus 5.0-7.4 times as long as wide (vs 5.2-5.6); P3 dactylus 2.6-3-4 times as long as wide (terminal spiniform seta included) (vs 3.1-3.5) with 5-8 spiniform setae on flexor margin in addition to the terminal one (vs 6-7); propodus 8.7-14.6 times as long as wide (vs 9.5-11.4), 3.8-6.0 times as long as dactylus (vs 4.1-4.6); by its P5 dactylus 3.3-4.9 as long as wide (vs 3-4.5) with 27-72 spiniform setae on flexor margin (vs 46-69), P5 propodus 3.4-5.1 times as long as dactylus (vs 4.1-4.7).

Figures

FIG. 2. — Caridina longicarpus Roux, 1926, A-H, J, K, NMB 6.V.a, lectotype: first pereiopod (A), second pereiopod (B), third pereiopod (C), fifth pereiopod (D), dactylus of third pereiopod (E), dactylus of fifth pereiopod (F), telson (G), uropodal diaeresis (H), male first pleopod (J), male second pleopod (K); I, L-N, ovigerous female paralectotype: pre-anal carina (I), eggs (L), cephalothorax (M), rostrum (N). Scale bars: A-D, G, H, J-L, N, 0.05 mm; E, F, 0.01 mm; I, 0.2 mm; M, 1 mm.

FIG. 3. — A-C, Caridina longicarpus Roux, 1926: live coloration ovigerous female in left lateral view (A), live coloration, ovigerous female, left lateral view of the rostrum (B); live coloration, ovigerous female in dorsal view (C); D, typical habitat, above Ciu waterfall, Canala, New Caledonia. Photographs: A, C, E. Vigneux; B, D, V. de Mazancourt.

FIG. 6. — Distribution of Caridina longicarpus Roux, 1926 and Caridina occidentalis n. sp. in New Caledonia with the sampling localities of the present study.Grey arrows indicate the main oceanic currents:North Caledonian Jet (NCJ); South Equatorial Current (SEC); SubTropical CounterCurrent (STCC); Vauban Current (VC); Alis Current of New Caledonia (ACNC); arrow widths indicate the strengths of the currents (from Cravatte et al. 2015); blue area and dashed line represent the barrier reef and its lagoon;black line separates watersheds draining the East coast to those draining the West coast; star indicates Oubatche, the locality where the lectotype of Caridina longicarpus was collected.