black sea red data book - Department of Biology

Xantho poressa (Qlivii, 1792)
Synonyms: Xantho rivulosus Risso 1816, Rathke, 1837; Xantho hydrophilus Pesta,
1918; Xantho rivulosus Drach & Forest, 1953; Xantho poressa: Holthuis, 1954.
Common names: Rom: Crabul de tarm, camiorca; Russ: Ksanto; Turk: Yalama;
Ukr: Ksanto.
Order DECAPODA
Family XANTHIDAE
Taxonomic description. Chelipeds with black fingers; carpus with antero-inner teeth
without tubercles or granulations. Dactylus with longitudinal margin; not completely
closed. Claws short, thick, short, hairy in adults. Size : length 28 mm, width 20 mm.
Colour variable - chestnut with red points. Fingers of chelae black. Eggs lilac.
IUCN Status
World level:
Black Sea Regional level: VU
Subregion level: VU
Distribution, Habitat type, Critical habitats, Limiting factors. Stony bottoms with
mussels. Found at depths of 0.5-3 m but can reach 20 m. Suffers from hard frost or
storms. Its biotope is also affected by developments along the shores such as the
building of seaside resorts and ports.
Biology. A species with a rather low fecundity. Reproduction during July-August.
Females spawn 800-1400 eggs. Larvae plankton with three metamorphic stages.
Population trends. During 1950-1970 very abundant in southern Romanian waters;
also frequent until 1980, but rare at present. A narrowed distribution area compared
with the 1980s. In 1993 only 20 ind.m" 2
at 6 m depth on the southern Romanian
littoral (Eforie South).
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