FAO Species Identification Guide for Fishery Purposes Western

1110 Crabs
Carpiliidae CARPILIIDAE
Reef crabs
Diagnostic characters: Carapace transversely
ovate; dorsal surface smooth, distinctly convex longitudinally
and transversely; front entire; a single low,
small tooth on each anterolateral margin of carapace.
Legs simple. Longitudinal ridges which
define efferent respiratory current usually
absent or strongly developed on
posterior part of endostome only; ridges 6
not clearly visible on anterior part of
5
endostome when mouthparts pushed
aside. Male abdominal segments 3 to 4
5 immovable, completely fused. Male 3
first gonopod stout, almost straight 2
or gently curved; male second 1
segments 3-5
anterolateral margin
gonopod elongate, longer or subequal
completely
with a single tooth
in length to male first gonopod. male abdomen fused
Habitat, biology, and fisheries: Benthic reef crabs. A single genus of Carpiliidae, Carpilius (with only 2
species in the Pacific), has fishery value. Both Pacific species of Carpilius, C. maculatus and C. convexus,
are occasionally collected for food.
Similar families occurring in the area
Only the Xanthidae and Eriphiidae (both families known as “stone and mud crabs”) can easily be confused
with carpiliids. These 3 taxa were all previously classified in a single family (Xanthidae).
Xanthidae: can be distinguished from carpiliids by the shape of the male first gonopods, which are slender
and sinuous (rather than stout, cylindrical), and the male second gonopods, which are very short (rather
than very elongate, longer than first gonopod).
Eriphiidae: can only be effectively distinguished from carpiliids by having all the male abdominal segments
freely movable, with the sutures clearly visible (versus male abdominal segments 3 to 5 completely fused,
sutures not discernible).
anterolateral
margin with more
than 1 tooth
Key to species of interest to fisheries occurring in the area
1a. Cream to pink ground colour in life, carapace with 9 large violet to maroon spots
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Carpilius maculatus
1b. Uniform red to reddish brown colour in life . . . . . . . . . . . . . . . . . . . . Carpilius convexus
List of species of interest to fisheries occurring in the area
The symbol is given when species accounts are included.
Carpilius convexus (Forsskål, 1775)
Carpilius maculatus (Linnaeus, 1758)
Xanthidae
all male abdominal
segments freely movable
Eriphiidae
References
Alcock, A. 1898. Materials for a carcinological fauna of India. No. 3. The Brachyura Cyclometopa. Part I. The family
Xanthidae. J. Asiat. Soc. Bengal, 67(2), No. 1:67-233.
Serène, R. 1984. Crustacés Décapodes Brachyoures de l’Ocean Indien occidental et de la Mer Rouge. Xanthoidea:
Xanthidae et Trapeziidae. Addendeum Carpiliidae et Menippidae - A. Crosnier. Faune Tropicale (ORSTOM),
24:1-400.