Caridina serratirostris De Man, 1892

Richard, Jasmine & Clark, Paul F., 2010, Caridina H. Milne Edwards, 1837 (Crustacea: Decapoda: Caridea: Atyoidea: Atyidae) - freshwater shrimps from eastern and southern Africa *, Zootaxa 2372 (1), pp. 305-337 : 310-313

Caridina serratirostris De Man, 1892

( Figs. 3–4 )

Caridina serratirostris De Man 1892: 382–385 , pl. 23, fig. 28. — Bouvier 1905: 75 (key); 1913: 463 (key); 1925: 218, figs. 480–486. — J. Roux 1926b: 248–249. — Kubo 1938: 92–93, fig. 21. — Holthius 1965: 25, fig. 8; 1978: 38, fig. 13a–h. — Tiwari & Pillai 1971: 82–83. — Chace 1997: 19, figs. 11a-r. — Shokita & Nishijima 1977 (not seen). — Shokita et al. 2002: 76 (not seen). — Shokita 2003: 250, figs. 18E, 19J, 20M (not seen). — Cai & Shokita 2006a: 246–247 ; 2006b: 2139–2140 . — Cai et al. 2007: 279–280 .

Caridina wyckii . — Weber 1897: 168 (partim).

Caridina serratirostris variety typical . — Edmondson 1935: 8, fig. 2g –l.

Caridina serratirostris serratirostris . — Fujino 1972: 7 (in Japanese, no figures). — Shokita 1975: 119 (not seen).

Caridina celebensis . — Holthuis 1978: 39, fig. 14a-i. — Yeo et al. 1999: 214, figs. 8, 9 (nec Caridina celebensis De Man, 1892 = valid species).

Nec Caridina wyckii Hickson, 1888 = valid species.

Nec Caridina wyckii sensu Weber 1897: 168 (partim) = Caridina brachydactyla De Man, 1908 .

Material examined. Types: Caridina serratirostris : Syntypes, Indonesia Borneo River , Saleyer, coll. M. Weber, 1888, det. J.G. De Man, ZMA Crust. De 102.624, 1 male, 3 ov. females; Borneo River , Saleyer , RMNH D nr. 2563, 4 ov. females; Bangkalanvir River, Saleyer, coll. M. Weber 1888, RMNH D nr.1771, 6 ov. females .

The ov. female from RMNH D. nr. 1771 with rostral formula (6) 26/6 is here selected as the lectotype; the remainder are paralectotypes.

Non-types: Mozambique Morrumbene Estuary, Portugese East Africa , pres. J. H. Day, University of Cape Town , det. J. Richard & P. Clark 2007, NHM 1955.3.5.31–36, 5 males, 5 females; stn MOR 95 A, UCT Ecological Survey, det. J. Richard & P. Clark, SAM A 19497 13 males, 1 ov. female, 10 females . South Africa Illovo or Umbibio River, Natal , ZMA Crust De 240151, 1 ov. female .

Description. Total length: 17–23 mm. Carapace length: 3–3.5 mm.

Rostrum ( Figs. 3a–c ): straight, mostly reaching end of antennular peduncle, or slightly longer. Length 3– 3.7 mm, 1.0–1.05 as long as carapace with 20–30 teeth on dorsal margin from proximal end to tip, 6–8 postorbital teeth; 7–12 teeth on ventral margin from proximal end leaving short distal part unarmed. Tip pointed. Formula (6–9) 20–30/7–12.

Antennular peduncle ( Fig. 3d ): 0.8–0.9 of carapace length. Stylocerite 1.1–1.6 of length of basal segment, always reaching beyond basal segment. Anterolateral tooth of basal segment 0.2–0.25 as long as second segment. 15–23 segments bearing aesthetascs.

First pereiopod ( Fig. 4a ): dactylus 1.3–1.4 as long as palm of propodus. Chela 2.5–2.65 as long as wide. Carpus 3–3.2 as long as wide, anterior excavation shallow.

Second pereiopod ( Fig. 4b ): Dactylus 1.6–1.75 as long as palm of propodus. Chela 4–4.2 as long as wide. Carpus 7–7.5 as long as wide. Brush-like setae at tip of chelae on first and second pereiopods.

Third pereiopod ( Figs. 4c–d ): dactylus 4–4.5 as long as wide with 10–12 spines including terminal spine. Propodus 3.5–4 as long as dactylus and 11–11.5 as long as wide with 15–20 spines along posterior margin. Carpus 0.7–0.8 as long as propodus with 1 large and 4 minute spines on inner margin. Merus 1.6–1.7 of carpus length with 4 large spines on posterior margin. Ischium bears 1 large spine.

Fifth pereiopod ( Figs. 4e–f ): dactylus 5.5–6 as long as wide with 15–25 spines in comb-like arrangement on inner margin. Propodus 15–16 as long as wide and 3.5–4.5 as long as dactylus with 15–18 spines along inner margin. Carpus 0.6–0.7 of propodus length with one large spine and 4 minute spines along inner margin. Merus 1.5–1.6 of carpus length, with 4 large spines on posterior margin. Ischium with large spine.

Setobranch: one seta on each pereiopod.

First male pleopod ( Figs. 4g –h ): endopod 0.3–0.35 of exopod length. No appendix interna present.

First female pleopod ( Fig. 4i ): endopod 0.6–0.9 as long as exopod.

Eggs ( Fig. 4j ) ca. 520; 0.40–0.45 × 0.25–0.30 mm in size.

Second male pleopod ( Figs. 2k–l ): appendix masculina 1.5–1.7 as long as appendix interna and 0.5–0.55 as long as endopod.

Sixth abdominal somite: 0.55–0.65 as long as carapace.

Telson ( Figs. 4m –o ): 1.1–1.2 as long as 6 th abdominal somite with 4–6 pairs dorsal spines including subterminal spines. 1 pair of plain long lateral spines, 1pair of shorter, plain lateral spines and 4–5 pairs of long, stalked, plumose processes present at rounded posterior margin. 1 fine median process present. Inner shorter lateral spines present in African and Madagascar forms, but not in type specimens.

Uropod ( Fig. 4p ): 15–20 diaeresis spinules.

Preanal carina ( Fig. 4q ): with strong curved spine.

Distribution. Mozambique, South Africa, Madagascar, Seychelles, Mauritius, Philippines, Malaysia, Indonesia, Japan, Australia, Fiji.

Remarks. De Man (1892) described C. serratirostris from the Lesser Sunda Islands, Indonesia. This species is unique in possessing 6–9 post orbital teeth on the dorsal margin of the rostrum, a ventral rostral margin with a short unarmed distal end, a long stylocerite that overreaches the first segment of the antennular penduncle being 1.1–1.6 times the first segment, slender pereiopods, 15–25 spines on the dactylus of the fifth pereiopod and four or five long slender plumose processes at the posterior margin of the telson. The specimens of C. serratirostris from Mozambique, South Africa and Madagascar ( Holthuis 1965, fig. 8c) possess two pairs of lateral spines (short and long lateral spines) on the posterior margin of the telson, whereas the syntypes possess a single pair of lateral spines. In all other respects the syntypes and the African specimens are similar. Although C. serratirostris has been recorded from Madagascar by Holthuis (1965), this is the first report of C. serratirostris from the African mainland.

Figures

FIGURE 2. Caridina africana Kingsley, 1882, ZMA De 102887; a, first pereiopod; b, second pereiopod; c, third pereiopod; d, dactylus of the third pereiopod; e, fifth pereiopod; f, dactylus of fifth pereiopod; g, first pleopod (male); h, endopod of first male pleopod; i, egg; j, appendix masculina; k, telson; l, posterior margin of telson; m, uropod diaeresis spinules; n, preanal carina. a–f, I, k–n ov. female; g–h, j male.

FIGURE 3. Caridina serratirostris De Man, 1892, NHM 1955.3.5.31–36, male: a, habitus; b, female, anterior region of cephalothorax. SAM A 19497, female: c, anterior region of cephalothorax. NHM 1955.3.5.31-36, male: d, antennular peduncle.

FIGURE 4. Caridina serratirostris De Man, 1892, NHM 1955.3.5.31–36, male: a, first pereiopod; b, second pereiopod; c, third pereiopod; d, dactylus of third pereiopod; e, fifth pereiopod; f, dactylus of fifth pereiopod; g, first male pleopod; h, endopod of first male pleopod; i, first female pleopod. SAM A 19497: j, egg. NHM 1955.3.5.31–36, male: k, second male pleopod; l, appendix masculina; m, telson; n, posterior margin of telson. ZMA. Crust. De. 102624, syntype male: o, posterior margin of telson. NHM 1955.3.5.31–36, male; p, uropod diaeresis spinules; q, preanal carina.