Description:-
Medium-sized specimens among Calappidae family. In live condition this species is dark brown dorsally and light brown ventrally; the colour fades to yellowish white creamy one in formaline preserved specimens. Carapace is a little broader than long; Clypeiform expansions on either side in the posterior region well developed. The most important peculiarity of this specimen is the presence of coarse tubercles throughout the carapace and outer surface of chelipeds and become squamiform on the posterior part of the carapace. Pereiopods slender and concealed beneath the clypeiform expansion on either side in the posterior part of the carapace. Outer surface of of the arm with wing-like expansion; tubercles present on the upper surface of the wrist and the outer surface of the palm. These tubercles become squamiform on the posterior part of the carapace. Antero-lateral border of the carapace crenulate whereas posterior border finely beaded. The clypeiform expansion of the carapace on the free edge with about six teeth like structure with beaded margins. The frontal region projects well beyond the orbits forming a small rostral- like structure. The pterygostomian region bears a few minute hairs. The wing – like expansion of the cheliped on the outer margin of the palm bears six teeth like structure and the fingers resembling the beak of a parakeet. The dorsal surface of carapace in the mid dorsal line bears two grooves originating from post gastric region to the end of the posterior part of the carapace. Chelipeds with quite different modification in the dactylus part. The right cheliped in the dactylus region bears additional claw-like structure projecting out on the external side of the finger base. Third maxilliped hairy only in merus of endopod and inner margins of exopod. Both borders in carpus, propodi and dactyli of third maxilliped hairy. Merus and carpus together with exopod of second maxilliped hairless. Exopod of first maxilla hairless. Scaphognathite of second maxillae longitudinally oval shaped with broad basal area. First maxilla hairy only on distal ends. Mandibles on the teeth bearing end bears sharp spine like structures. Antennae as long as antennule.
Synonyms:-
Cancer gallus Herbst, 1803; Cancer (Calappa) gallus Latreille, 1816a; Gallus gallus de Haan, 1833-1849 (1837); Calappa gallus Milne Edwards H., 1837;Calappa gallus capellonis Laurie 1906; Jayabaskaran et al. 2000;Calappa gallus, Tirmizi & Kazmi 1988; Kumar et al. 2007.
References:-
Alcock,A. (1895-1900). Materials for the Carcinological Fauna of India (Nos. 1-6. The Brachyura, Oxyrhyncha, Oxystoma, Cyclometopa, Primigenia or Dromiacea and Catometopa or Grapsoidea). J. Asiat. Soc. Beng., 64: 157-291, 65: 134-296, 67:67-233, 68: 1-104 and 123-169, 69: 279-456 (Reprinted in 1984, International Books and Periodical Supply Service, New Delhi).
Biju Kumar, A., M. Sushil Kumar., S.M. Raffi and S. Ajmal Khan (2007). Diversity of brachyuran crabs associated with trawl by-catch in Kerala coast, India. Ind.J. Fis. 54 (3): 283-290.
Biju Kumar, A., Sushil Kumar, M, and Galil, B.S. (2013). Calappid and leucosiid crabs (Crustacea: Decapoda: Brachyura) from Kerala, India, with the description of a new species of Mursia Desmarest, 1823, from the Arabian Sea and redescription of M. bicristimana Alcock & Anderson, 1894. Zootaxa, 3746 (4): 529-551.
Sushilkumar, M. (2013). Diversity and proximate composition of brachyuran crabs in the trawl by-catch of Kerala coast. PhD Thesis submitted to University of Kerala, India.