Caridina turipi Mazancourt & Boseto & Marquet & Keith 2020, sp. nov.

Caridina turipi sp. nov.

urn:lsid:zoobank.org:act: 9DB3C416-1B20-4CF4-A3D2-CDC36AA8309C

Figs 2C, 11

Caridina cf. weberi sp. 1 – de Mazancourt et al. 2019a: 166, 169–170.

Etymology

Named after the river Turipi, in Choiseul Island, the type locality where this new species occurs. The name is used as a noun in apposition.

Material examined

Holotype

SOLOMON ISLANDS • ♀, cl 5.9 mm; Choiseul Island, Turipi River; 07°00.661´S, 156°49.075´E; 51 m a.s.l.; 15 Oct. 2014; P. Gerbeaux, P. Keith and G. Marquet leg.; DNA voucher: CA1359; MNHN- IU-2014-20876.

Paratypes

SOLOMON ISLANDS – Choiseul Island • 1 ♀ ovig., cl 4.9 mm; same collection data as for holotype; MNHN-IU-2014-20877 • 1 ♀ ovig., cl 5.2 mm; same collection data as for holotype; MNHN- IU-2014-20878 • 1 ♀ ovig., cl 5.4 mm; same collection data as for holotype; MNHN-IU-2014-20879 • 1 ♀ ovig., cl 5.6 mm; same collection data as for holotype; MNHN-IU-2014-20880 • 1 ♀ ovig., cl 5.7 mm; same collection data as for holotype; MNHN-IU-2014-20881 • 1 ♀ ovig., cl 4.6 mm; Vorama River; MNHN-IU-2014-20882 • 1 ♀ ovig., cl 5.3 mm; 06°58.687´S, 156°46.745´E; 15 m a.s.l.; 11 Oct. 2014; P. Gerbeaux, P. Keith and G. Marquet leg.; DNA voucher: CA1349; MNHN-IU-2014-20883 • 1 ♀ ovig., cl 6.3 mm; Creek 2; 06°59.027´S, 156°47.913´E; 132 m a.s.l.; 14 Oct. 2014; P. Gerbeaux, P. Keith and G. Marquet leg.; MNHN-IU-2014-20884.

Comparative material

Caridina sumatrensis (De Man, 1892)

INDONESIA • 1 syntype, ♀, cl 4.9 mm; Sumatra, Batak land, near Deli; Dec. 1890; C. Moesch leg.; MNHN-IU-2015-1758 • 1 ♀ ovig., cl 5.1 mm; Java; NMB 6.II.b.

THAILAND • 1 ♀ ovig., cl 4.8 mm; "Siam"; 1884; Harmand leg.; MNHN-IU-2015-1759.

VIETNAM • 1 ♀, cl 4.0 mm, 1 ♀ ovig., cl 4.0 mm; Conchinchina, forest ponds; Jul. 1884; Harmand leg.; MNHN-IU-2015-1760.

Description

CEPHALOTHORAX. Suborbital angle indistinguishably fused with antennal spine. Pterygostomian margin rounded. Rostrum (Fig. 11k): straight, short, 0.4–0.5 of cl, reaching to end of second segment of antennular peduncle, armed with 11–15 teeth on dorsal margin, 2–4 of them situated on carapace behind orbital margin, ventral margin with 2–4 teeth. Eyes well developed, anterior end reaching to 0.76 length of basal segment of antennular peduncle. Antennular peduncle 0.37–0.50 times as long as carapace. Anterolateral angle reaching 0.36 length of second segment, second segment longer than third segment. Stylocerite reaching to 0.86 length of basal segment of antennular peduncle.

PEREIOPODS. Epipods on first four pereiopods. P1 (Fig. 11a): chela about 1.9–2.1 times as long as wide, movable finger 2.6–3.0 times as long as wide, 0.9–1.0 times length of palm; carpus 1.5–1.8 times as long as wide. P2 (Fig. 11b) more slender and longer than first pereiopod, with chela 2.6–3.1 times as long as wide: movable finger 4.6–4.9 times as long as wide, 1.5–2.1 times length of palm; carpus slender, 5.5–6.6 times as long as wide. P3 (Fig. 11c): stout, dactylus (Fig. 11e) 3.0–3.3 times as long as wide (terminal spiniform seta included) with 5–6 spiniform setae on flexor margin in addition to terminal one; propodus 8.8–10.5 times as long as wide, 4.1–4.7 times as long as dactylus. P5 (Fig. 11d): dactylus (Fig. 11f) 3.3–4.5 as long as wide, with 37–46 spiniform setae on flexor margin; propodus 13.5–15.3 times as long as wide, 4.1–5.2 times as long as dactylus.

ABDOMEN. Third abdominal somite with moderarely convex dorsal profile. Sixth abdominal somite 0.43 times as long as carapace, 1.3 times as long as fifth somite, slightly shorter than telson.

TELSON (Fig. 11i). 2.3 times as long as wide, with four or five pairs of dorsal spinules and pair of dorsolateral spinules; posterior margin without median process, rounded, with 4–7 long intermediate setae longer than lateral ones.

MALE PLEOPODS. No males.

PRE- ANAL CARINA (Fig. 11g). High, unarmed.

UROPODAL DIAERESIS (Fig. 11h). With 17–21 spinules.

EGGS (Fig. 11j). Size: 0.35–0.44 × 0.21–0.25 mm.

Habitat

This species is largely rheophile and prefers fresh and well-oxygenated waters from the lower to the higher course of rivers.

Colour pattern

Unknown.

Distribution

As far as we know, this species occurs only in Choiseul Island.

Remarks

This new species looks like C. sumatrensis De Man, 1892 by its number of dorsal teeth on the rostrum situated on carapace behind orbital margin 2–4 (vs 2–6 in C. sumatrensis) and the proportions between the joints of pereiopods like P1 carpus 1.5–1.8 as long as wide (vs 1.6–2.0), P2 carpus 5.5–6.6 as long as wide (vs 5.2–6.4), P3 dactylus 3.0–3.3 as long as wide (vs 2.7–3.7), P5 dactylus 3.3–4.5 times as long as wide (vs 3.2–4.3). However, it differs by its rostrum that has fewer teeth the on dorsal margin, 11–15 (vs 15–22), as well as on its on the ventral margin, 2–4 (vs 2–7), its P1 chela is shorter, 1.9–2.1 times as long as wide (vs 2.0–2.4) and its P5 dactylus has more spiniform setae on the flexor margin, 37–46 (vs 36).

In contrast to previous definitions (Karge & Klotz, 2007), we consider that the C. typus group is not characterized by the absence of dorsal teeth on the rostrum. Bouvier (1925) includes many species with an armed rostrum in his “ groupe du C. typus ”; however, we consider some of them to be part of the C. weberi species group (see below).

According to our study, the length of setae on the telson (namely plumose terminal setae on the telson subequal to lateral ones or slightly longer) is a better criteria to characterize this group that agree with our molecular results (see de Mazancourt et al. 2019a where it appears as a monophyletic group). We thus consider some species like C. turip i or C. sumatrensis that have numerous dorsal teeth to be part of the C. typus group.