Cryptoplax sykesi Thiele, 1909

Dell’Angelo, Bruno, Gori, Sandro, Baschieri, Leonardo & Bonfitto, Antonio, 2010, Chitons (Mollusca, Polyplacophora) from the Maldive islands, Zootaxa 2673 (1), pp. 1-38 : 32

Cryptoplax sykesi Thiele, 1909

( Figures 11M–O )

Cryptoplax sykesi Thiele 1909: 54 , pl. 6, figs 83–86; Leloup 1940: 9, fig. 3, pl. 2; Ghobashy & Kotb 2002: 6; Anseeuw & Terryn 2004: 16, fig. 55; Dell’Angelo et al. 2004: 60, pl. 6, figs 14–15 (bibliography and synonymy).

Type: unascertained (fide Ferreira 1983: 287).

Type locality: Red Sea, “Gimsah-Bai”.

Material examined: M13: 1 intermediate valve; M20: 2 intermediate valves; M65: 2 intermediate valves; MLD02A: 2 intermediate valves; LB04: 1 intermediate valve; LB05: 21 valves (20 intermediate and 1 tail).

Remarks: Detailed descriptions of this species are given by Leloup (1940) and Ferreira (1983).

We attribute our valves to Cryptoplax sykesi on the basis of the smooth jugal area and the sculpture of the lateropleural area, with 5–6 longitudinal riblets, some broken up in granules near the apex ( Fig. 11O ). Our material match with the valves found in Madagascar (compare pl. 6, Figs 14 –15 in Dell’Angelo et al. 2004), only the Maldive intermediate valves seem more elevated than the Madagascar ones.

This is the first report of this species from the Maldive Islands.

Distribution: Cryptoplax sykesi is an intertidal to shallow sublittoral species, widespread in the western Indian Ocean. It is known from the Red Sea, Somalia, Tanzania, Mozambique, Natal, Amirante Islands, Geyser Bank (North of Mozambique Channel), Madagascar and the Maldive Islands.

Figures

FIGURE 11A–L, Cryptoplax burrowi (E.A. Smith, 1884), Maldive. A–B, head valve, MLD02A. A, dorsal view. B, detail of the sculpture. C–E, intermediate valve, M65. C, dorsal view. D, detail of the sculpture. E, lateral view. F–H, tail valve, M65. F, dorsal view. G, lateral view. H, detail of the sculpture. I–L, living specimen, M07, girdle elements in situ. I, marginal spicules. J, ventral spicules. K–L, dorsal scales. M–O, Cryptoplax sykesi Thiele, 1909, intermediate valve, Maldive, M13. M, dorsal view. N, lateral view. O, detail of the sculpture. Scale bars 1 mm: C, E–G, N; 500 µm: A, M; 100 µm: B, D, H, I, K, L, O; 50 µm: J.

FIGURE 14A–C, NHM labels, with informations on type material. A, Chiton laqueatus Sowerby, 1842, 5 specimens (lectotype and 4 paralectotypes), NHM 1988071/1-5. B–C, Cryptoplax burrowi E.A. Smith 1884. B, NHM 1992 053, syntypes, 4 specimens, H. Cuming colln., Port Adelaide, S. Australia. C, NHM 1881.11.1.100, syntype, detached valves, coll. Coppinger, Port Molle, Queensland. D, NHM label of Callochiton platessa Gould, 1846, S. Nilandu Atoll, Maldive, NHM 1903.4.11.71, living specimen collected by J.S. Gardiner (considered as Callochiton sp. in this work).