Acanthochitona penicillata ( Deshayes, 1863 )

Dell’Angelo, Bruno, Gori, Sandro, Baschieri, Leonardo & Bonfitto, Antonio, 2010, Chitons (Mollusca, Polyplacophora) from the Maldive islands, Zootaxa 2673 (1), pp. 1-38 : 19-21

Acanthochitona penicillata ( Deshayes, 1863)

( Figures 7A–D , 12K )

Chiton penicillatus Deshayes 1863: 41 , pl. 6, figs 8, 10.

Acanthochitona penicillata ; Strack 1993: 23, pl. 5, fig. 6; Dell’Angelo et al. 2004: 56, pl. 5, figs 10–16 (bibliography and synonymy); Anseeuw & Terryn 2004: 17, figs 56–57.

Acanthochitona cf. A. penicillata ; Ferreira 1983: 284, fig. 32.

Type: probably lost (fide Strack 1993: 25).

Type locality: Réunion .

Material examined: M13: 11 valves (1 head and 10 intermediate); M17: 1 intermediate valve; M26: 1 intermediate valve; MLD02A: 4 intermediate valves; MLD04A: 1 spm (estimated length 6.5 mm, slightly curled, Fig. 12K ); MLD04B: 2 intermediate valves; LB05: 102 valves (10 head, 86 intermediate and 6 tail).

Remarks: A detailed description of this species is given by Ferreira (1983).

Although it is difficult to reliably evaluate this species-group, we attribute the analyzed material to A. penicillata mainly on the basis of the smooth jugal area (except for discrete transversal growth rugae), shape of granules and distribution of aesthetes. The present material match with the valves reported from Madagascar (compare pl. 5, Figs 10 –16 in Dell’Angelo et al. 2004). The granules, of narrow isosceles triangle shape, show a central megalaesthete and two–three micraesthetes near the apex of the triangle, from which an irregular stem is extending towards the next granule ( Figs 7B–C ).

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

Distribution: Acanthochitona penicillata is a locally common intertidal to shallow subtidal species, widespread in the western Indian Ocean. It is known from the Red Sea, Suez Canal, Yemen, Socotra Island, Madagascar, Tanzania, Somalia, and the islands of Seychelles, Réunion, Mauritius and the Maldive Islands.

Figures

FIGURE 7A–D, Acanthochitona penicillata (Deshayes, 1863), Maldive. A–C, intermediate valve, MLD02A. A, dorsal view. B–C, granules, dorsal and lateral views, respectively. D, dorsal view of tail valve, LB05,. E–G, Acanthochitona sp., LB05, intermediate valve. E, dorsal view. F–G, granules, dorsal and lateral views. H–Q, Craspedochiton cf. laqueatus (Sowerby, 1842), Maldive, valves dismounted from living specimen, M59. H–J, head valve. H, dorsal view. I, detail of the sculpture. J, frontal view. K–M, intermediate valve. K, dorsal view. L, frontal view. M, detail of the sculpture. N–Q, tail valve. N, dorsal view. O, ventral view. P, lateral view. Q, posterior view. Scale bars 1 mm: H, J–L, N–P; 500 µm: A, D, Q; 100 µm: E, I, M; 50 µm: B, C, F, G.

FIGURE 10A–F, Craspedochiton laqueatus (Sowerby, 1842), NHM type material, Philippines, Mindoro, Calapan, not coated. A–C, E–F, valves detached from the paralectotype NHM 1988071/2. A–B, head valve, dorsal and lateral views, respectively. C, intermediate valve (ii), dorsal view. E–F, tail valve, dorsal and lateral views. D, hyponotum scale in situ, from the paralectotype NHM 1988071/3-5, length 11.3 mm (Fig. 12Q). Scale bars 1 mm: A–C, E–F; 10 µm: D.

FIGURE 12A, Parachiton hylkiae mauricejayi Schwabe, 2002, living specimen, Maldive, LB03B, length 12.8 mm. B, Ischnochiton albinus Thiele, 1911, living specimen, Maldive, M13, length 5.2 mm. C, Ischnochiton feliduensis E.A. Smith, 1903, Maldive, Felidhoo Atoll, Holotype, NHM 1903.9.17.25, length 6 mm. D, Tegulaplax hululensis (E.A. Smith, 1903), living specimen, Maldive, M28, length 10.5 mm. E–F, Callochiton sp., S. Nilandu Atoll, Maldive, NHM 1903.4.11.71 (living specimen collected by J.S. Gardiner), length 6.6 mm. G, Lucilina sp., living specimen, Maldive, M07, length 4 mm. H, Lucilina indica (Leloup, 1981), holotype (MNHN), Madagascar, Tuléar, length 8 mm. I, Acanthopleura miles (Carpenter in Pilsbry, 1893), living specimen, Japan, Okinawa, Sesoko Island, length 29.2 mm. J, Schizochiton incisus (Sowerby, 1841), living specimen, Indonesia: inside lagoon of Woka Island, off South Halmahera, 1°2.02’S, 128°13.97’E (ZSM Mol 20052075), length 40 mm. K, Acanthochitona penicillata (Deshayes, 1863), living specimen, Maldive, MLD04A, length 6.5 mm. L, Craspedochiton cf. laqueatus (Sowerby, 1842), living specimen, Maldive, M59, length 13.5 mm. M–Q, Craspedochiton laqueatus (Sowerby, 1842), NHM type material, Philippines, Mindoro, Calapan. M, lectotype (NHM 1988071/1), length 17.4 mm. N, paralectotype (NHM 1988071/2), length 17.5 mm. O–Q, paralectotypes (NHM 1988071/3-5), length respectively 16, 13.2 and 11.3 mm. R–S, Cryptoplax burrowi (E.A. Smith, 1884), living specimen, Maldive, M07, length ca. 11.7 mm. T, Cryptoplax burrowi (E.A. Smith, 1884), living specimen, Indonesia, ZSM Mol 20033081, length 25.4 mm. U–X, Cryptoplax burrowi (E.A. Smith, 1884), NHM 1992 053, syntypes, H. Cuming colln., Port Adelaide, S. Australia, length respectively 56.4, 38.5, 47 and 45.1 mm.