Calappa bilineata
Scientific Name:-
Calappa bilineataCommon Name:-
Box Crab
Malayalam Name:-
Iruvarayan Pettinjandu
Category:-
Crabs
Status:-
Not evaluated
Description:-
These include relatively large sized specimens among Calappidae family. The most important and quick identifying feature of this species is the presence of large spines on the posterior margin of the carapace and the clypeiform expansions. Carapace nearly smooth, covered by minute red coloured spots which becomes invisible on the posterior region. In the freshly collected young specimen dorsal surface of carapace densely stippled anteriorly with maroon dots, two pale ocelli posteriorly; maroon undulating longitudinal lines border cardiac and gastric regions, maroon crescents mark orbits; posterior carapacial teeth pale yellow. Pereiopods, tip of spines on carapace and fingers light yellowish/white in appearence. The bright colour fades in formaldehyde preserved specimens. Presence of two eye spots like colouration behind the orbital region, one each behind either orbit resembling a false eye. Females are larger in size than males as per the collection obtained in the present investigation. The extreme length of carapace about two-third its extreme breadth. Well-developed clypeiform expansions with spiny margins (6 in numbers). A median spine present on the posterior border of the carapace in the middle line. Spines also present on either side of it. All the spines on the posterior border including those in the posterior part of clypeiform expansions granulated. Antero-lateral margins of carapace beaded. Anterior border of endostomial septum strongly convex. Two deep grooves present on the dorsal side of carapace with dark pinky coloration. A toothed ridge present near the lower border of the palm. The upper margin of the palm bears 6/7 toothed structures. Pereiopods laterally flattened. The abdomen of both male and females have seven segments each; and that of female is broader than male. The endostomial septum has its anterior border projecting and strongly convex. Exposed surfaces of third maxillipeds hairy. The ischium of third maxilliped bears toothed structures on the inner margin. The margins of propodi and dactyli of second maxilliped hairy. Endopod of first maxilliped hairy. Scaphognathite of second maxillae triangular, whereas outer margin of first maxilla bear hairs. Mandible on the lower margin tapering. Antennae smaller than antennules.
Remark:-
Bijukumar et al. (2013) and Sushilkumar (2013) reported this species from the trawl bycatch of Kerala Coast, India.
Habitat:-
Muddy and sandy bottom
Synonyms:-
Calappa philargius, Henderson 1893; Alcock, 1896; Laurie, 1906; Sankarankutty, 1962; Sekharan et al., 1962; Galil, 1997; Rice, 1999; Calappa bilineata Ng, Lai & Aungtonya 2002; Calappa cristata Fabricius, 1798; Cancer inconspectus Herbst, 1794; Cancer philargius Linnaeus, 1758.
References:-
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.
Ng, P.K.L., J.C.Y. Lai and C. Aungtonya (2002). The box and moon crabs of Thailand, with description of a new species of Calappa (Crustacea: Brachyura: Calappidae, Matutidae). Phuket Marine Biological Center Special Publication, 23, 341–360.
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.