Macropipus arcuatus Leach, 1814

Macropipus arcuatus imageSynonyms: Portunus rondeletii Risso, 1816; P. longipes Rathke, 1837

Common names: Bulg: Rak plubet; Rom: Crabul rosu; Russ: Krab-plavunets; Turk: Calpara; Ukr: Krab-plavunets'



Taxonomic descriptions: Front not produced into teeth; anterolateral margin of the carapace with 4 unequal teeth; the third small, hardly visible. Flagellum of antenna about 2.5 times longer than eye. Chelipeds bigger with 2-3 ridges of male, smaller and smooth to female. Carpus with a strong posterio-superior spine. Fingers with little teeth (2-3); small terminal teeth. Dactylus of the fifth pereiopods like a lance, consolidated with a longitudinal ridge. Female with larger abdomen to base than male, could not cover the eggs completely. Size: lengths -18 mm; width - 22 mm. Colour: red purple for specimens from fields with Phyllophora.

Macropipus arcuatus arealIUCN Status
    World level:
    Black Sea Regional level:
    Subregion level: VU


Habitats type, Critical habitats, Limiting factors: Iliophilic species, to depth of 30-70 m; favourite biotop: very deep covered by Phyllophora oozy sea grounds. Reduction of Phyllophora fields, which were a favourite biota for this crab.

Biology: Species with a high prolificity (up to 3 thousand eggs); reproduction begins in spring; the eggs are yellow lying in the shape of cluster with 3-4 eggs into a verticillum.

Population trends: In the past abundant in Phyllophora fields and on the entire Romanian littoral (hundred ind/m2). In the last 20 years species has become very rare.

Threats: Hypoxic conditions on the shelf.

Conservation measures taken: None.

Conservation measures proposed: Mitigation of negative environmental impacts.


  1. Borcea I., 1926 - Note sur quelques crabes de rivage du littoral Roumain. Ann. Sc. Univ. Jassy, XIV: 140.
  2. Borcea I. 1926 - Donnees sommaires sur la faune de la Mer Noire (littoral de Roumanie). Ann. Sc. Univ. Jassy, XIV: 536-583.
  3. Borcea I. 1931 - Action du froid sur la faune littoral de la Mer Noire. Ann. Sc. Univ. Jassy XVI: 751-759.
  4. Bacescu M., Dumitrescu E., Marcus A., Palladian Mayer R., 1963 - Donnees quantitatives sur la faune petricole de la Mer Noire a Agigea (secteur Roumain) dans les conditions speciales de l’annee 1961. Trav. Hist. Nat. Gr. Antipa, IV, 131-153.
  5. Bacescu M. 1967 - Fauna RSR (DECAPODA), 4, 9: 7-335.
  6. Bacescu M., G.I. Muller., M-T Gomoiu, 1971 - Ecologie marina (Marine Ecology), IV:7-274.
  7. Gutu Modest, 1980 - Recent changes in the Decapod fauna of the Romanian Black Sea littoral. Trav. Mus. Hist. Nat “Gr. Antipa, 21,103-110.

Compiled by: C. Dumitrache