Zalasius indica     (Crab)
Organism information awaits expert curation
Class: Malacostraca

Size (female): Breadth 37 mm, length 33 mm.

Carapace highly tomentose, conspicuously convex in either directions, regions indicated by deep grooves and postero-lateral region with few military granules. Front narrow but broader than orbit, bilobed with median part deflexed and almost touching the epistome thereby separating antennulary fossa of either side; frontal lobes not separated from inner angle of orbit. Orbit complete with its upper border divided into three regions by two deep fissures of which inner being more prominent. Outer angle of orbit not pronounced and not forming any tooth or lobe. Antero-lateral border immediately outside orbit forming a concave zone followed by uniformly convex tuberculated border, the line of tubercles curving inwards and ending on either sides of cardiac region. Postero-lateral border short and more or less straight. Antennules fold obliquely; antenna separated from the orbit by the fusion of basal antennal joint to the inner side of orbit, antennal flagellum reduced. Pterygostomian, sub-hepatic and sub-branchial regions tomentose; pterygostomian region granulated.
External maxilliped not closing the buccal cavern completely, its exposed surface completely clothed in plumose hairs. Ischium narrow and elongated, widening distally, merus longer than broad with concave inner and outer borders and rounded distal border. Palp short, attached to the middle of the distal end of merus and partly concealed in a groove at the inner distal end of merus; exopod with short flagellum.
Chelipeds sub-equal and like the walking legs completely covered with hairs excepting the inner side of propodus and fingers. Merus short and high, being higher than long, its borders tuberculate, similar tubercles found on upper surface of the outer side also. Ventral hinge of merus elongated (length of merus along ventral border including the ventral hinge considerably more than length along the upper border but slightly less than height of merus) and almost coming in contact with the proximal hinge of propodus. Carpus with a line of tubercles on the inner side in the proximal half and at about the middle of the segment drooping down on the inner side. Propodus higher than long (length measured along the upper border) and shorter than movable finger, upper border slightly on the inner side with 3 rows of tubercles reducing in size distally. Outer surface of propodus tuberculated, a group of tubercles on the inner side of propodus at the proximal end. Ventral border of propodus with a longitudinal row of about eight tubercles. Fingers sharp, pointed with serrated cutting edges and leaving a wide gap at the proximal end between them.
First two pairs of walking legs sub-equal and longer than last two pairs, fourth pair shortest. Dactylus of all legs thin and long ending in sharp hook-like claw, its length more than the length of merus in the last two legs but about as long as merus in first two legs.
Sternal segment of cheliped with three enlarged tubercles arranged in a triangle - two on the outer and one on the inner side; a deep groove between inner tubercles of either side through which project out the long pleopods. Each of the following sternal segments with one such tubercle reducing in size posteriorly (those on last two segments being indistinct); another transverse tubercle between two sternal segments and closer to the base of legs, being prominent only on the last two segments. Abdomen in female of seven separate segments with a median broad convex ridge along the entire length of abdomen except in the last segment. Third segment broadest from where abdomen narrowing distally, end segment conical and broader than long.

Synonym (s)

Common Name (s)
Economic Importance and Threats

Habitat:  Coastal


• Tamil Nadu, Devipattinam INDIA

Literature Source(s)
  • Sankarankutty, C (1966) On Decapoda Brachyura from the Gulf of Mannar and Palk Bay Proceedings of the Symposium on Crustacea Marine Biological Association of India, Mandapam Camp Part I 347-362 Available at -
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -

Page last updated on:2010-11-25

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