Genus Anamathia Smith, 1885

Amathia Roux 1828: 8, 11, 12, pl. 3; H. Milne Edwards 1834 a: 285, 286.

Pisa (Amathia) De Haan 1839: 78 (key), 84.

Anamathia Smith 1885: 493 (replacement name for Amathia Roux, 1828); Miers 1886: 25 (in part); Alcock 1895: 165 (list); Faxon 1895: 8; Bouvier 1940: 345; Ng et al. 2008: 102 (list); Tavares and Santana 2018: 202, 208.

Type species.

Amathia rissoana Roux, 1828, by monotypy, gender feminine.

Diagnosis.

Carapace pyriform with spines. Pseudorostral spines relatively long, straight, stout, cylindrical, slight diverging at approximately 20° angle or less. Supraorbital eave with blunt preorbital angle; weak postorbital lobe small, round anterior margin. Carapace with strong spines; 3 spines medially: metagastric, cardiac, intestinal; strong lateral branchial spines pointed outwards and downwards (Figs 16A, 17A). Antennal flagellum shorter than pseudorostral spines (Fig. 17B). Basal antennal article longer than broad, distal angle blunt, relatively straight outer margin. Distal angle of buccal frame elongated, forming strong blunt angle. Pterygostomial region with granules on outer margin (Fig. 17B). Chelipeds slender, articles with rounded margins; propodus slender, longer than fingers; carpus with spines on outer margin; merus with spine on distal angle, rounded margins. Ambulatory legs slender, articles with rounded margins; merus with blunt distal angle; P2 longest (Figs 16A, 17A). Male thoracic sternum concave anteriorly, constricted between sternites 1, 2 and 3, 4; sternites 3, 4 with lateral margin slightly constricted. Male pleon triangular, telson triangular, margin round; with raised granules on somites 2-5 (Fig. 17B). G1 straight with flattened sharp tip (Fig. 18A-D); G2 with distal tip round (Fig. 18E, F).

Remarks.

The genus was first described as Amathia by Roux (1828). The name was changed to Anamathia by Smith (1885), as the earlier name was preoccupied for a bryozoan (Lamouroux 1812). This genus was synonymised by Rathbun (1925) under Rochinia A. Milne-Edwards, 1875, with no detailed explanation. Ng et al. (2008) listed the genus as valid as well but again with no explanation. Tavares and Santana (2018) discussed the matter and considered this genus as valid, listing the morphological differences from Rochinia and Scyramathia . Anamathia hystrix (Stimpson, 1871) was also transferred to this genus by Tavares and Santana (2018) without explanation. Although the external features of this species resemble A. rissoana, R. hystrix has a strong preorbital spine and a pronounced mesogastric spine in the middle of the carapace; and on the basis of this as well as unpublished genetic data, we are of the opinion that it should not be placed in this genus. As such, R. hystrix together with the rest of the Atlantic and East Pacific Rochinia sensu lato species will be dealt with separately by Lee et al. (in prep).