Cymothoa frontalis Milne Edwards, 1840

(Fig. 1 p–r)

Cymothoa frontale (Cymothoé frontal) Milne Edwards, 1840: 271.

Cymothoa frontalis .— White, 1847: 110.— Heller, 1868: 146.— Schiöedte & Meinert, 1884: 226, tab. VI (Cym. XXIV), figs 1, 2.— Gerstaecker, 1901: 261.— Nierstrasz, 1931: 136.— Avdeev, 1978b: 282; 1990: 32, figs 1–6.— Trilles, 1975: 980, pl. I (3–5).— Bruce, Lew Ton & Poore, 2002: 175.— Trilles & Bariche, 2006: 228: figs 1–3.— Rameshkumar, Ravichandran, Sivasubramanian & Trilles, 2013d: 42, fig. 1b.— Aneesh, Helna, Sudha, Helna, Anilkumar & Trilles, 2014: 339–353 fig. 1b–e.— Aneesh, Helna, Sudha, Anilkumar & Trilles, 2015: 1–28, figs 1–15.

Uncertain identity

Cymothoa frontalis .— Dana, 1853: 750, pl. 49 (fig. 12a, b).— Trilles, 1994: 143.

Type and type locality. Syntypes held at National Museum of Natural History, Paris (MNHN-IU-2007-4059). 2 ovig. females (17, 22 mm), from the Indian Ocean; precise location and host not known (Milne Edwards, 1840).

Material examined. 1 ovig. female (25 mm), Muthupettai, southeast coast India 18 May 2010, from Strongylura leiura, coll. G. Rameshkumar (CAS / MBRM C- 89).

Remarks. Cymothoa frontalis can be distinguished by the narrow and elongate body; sub-triangular cephalon; short antero-lateral angles on pereonite 1 which do not reach half the length of the cephalon; narrow pleon and subequal pleonites; uropods shorter than the length of the pleotelson; and a pleotelson which is almost square. Cymothoa frontalis also appears to have the posterolateral margins of pereonites more curved than Trilles’s (1975) specimen.

Aneesh et al. (2015) provide detail description and life stage of C. frontalis collected on Strongylura strongylura (van Hasselt, 1823) (family Belonidae) from Indian material. The Indian specimen is very similar to the syntype in the subtriangular cephalon not being immersed in pereonite 1 and pereonite 1 with minute anterolateral margins that do not reach beyond the anterior half of the cephalon, but differs from the syntype in having a more rounded pleotelson posterior margin, uropodal rami not reaching half of pleotelson length, and a subtruncate cephalon anterior margin.

Cymothoa frontalis differs from within the genus pereonite 1 anterolateral margins broad, with round or subtruncate projections; extending more than half the length of cephalon; pereopod 7 merus without bulbous protrusion on inferior distal margin; pleonites subequal in width.

Dana (1853) mentioned that C. frontalis was also known from the Pacific Ocean (Hawaii). Trilles (1994) added this citation into the C. frontalis synonymy with uncertainty (Hadfield, 2012; Martin et al, 2016).

Colour. Female have light grey with the highly pigmented dorsal surface.

Size. Ovig. females 17–25 mm; non ovig. female 20 mm (Aneesh et al. 2015).

Distribution. Known from the Indian Ocean (White 1847; Schiöedte & Meinert 1884; Trilles 1975), Singapore (Heller 1868), Bangkok (Schiöedte & Meinert 1884; Trilles 1975), west coast of Australia (Avdeev 1978b) and India (Rameshkumar et al. 2013d; Aneesh et al. 2015).

Hosts. Cymothoa frontalis previously recorded from the family Cyclopteridae: on the gills of Cyclopterus sp. (see White 1847). Recently this species record from the family Belonidae: Strongylura leiura (Bleeker, 1850) (Rameshkumar et al. 2013d) and Strongylura strongylura (Aneesh et al. 2015)