Pilumnus hirtellus Linnaeus, 1758

Pilumnus hirtellus imageSynonyms: Pilumnus hirtellus Czerniavsky 1884; Cancer hirtellus (L. 1766)

Common names: Engl: Mud crab; Rom: Crabul paros; Russ: Volosaty krab; Turk: Camur yengeci; Ukr: Volokhaty krab

Order: DECAPODA

Family: XANTHIDAE

Taxonomic descriptions: Small-size crab, very hairy. Anterolateral side shorter than posteriolateral side. Front with an obvious median split and two lateral smaller each of them with a preorbital spine; both lobs delimited, toothed. Superior margin of the orbit without spine, the inferior and both edges with spine. Anterolateral edge with 4 big spines. Unequal chela; the right chela is stronger. Merus short. Carpus hirsute with tubercles and a big interdistal spine. Hairy species with spines all over the body and palm.The nude fingers with tubercles teeth. Pereiopods II-V without spine. The other pereiopods very hairy with long, conical dactylus with terminal craws. Size: length - 20 mm; width - 28 mm. Color: carapace and superior side of pereiopods reddish - violet. Fingers of chela brown. Inferior part of pereiopods ivory. The young less than 5 mm completely white, like chalk, especially in winter.

Pilumnus hirtellus arealIUCN Status:
    World level:
    Black Sea Regional level:
    Subregion level: VU

Distribution:

Habitat type, Critical habitats, Limiting factors: In meddlittoral and superior infralittoral on different substrata; favourite biotop being stony grounds with alga and mussels at depth of 0-10m .Throughout the Mediterranean Sea and the eastern Atlantic Ocean from the North Sea to Cape Verde Islands. Hard frost, storms and pollution in the coastal zone.

Biology: Sedentary species; spawns up to 4 thousand eggs; planktonic larvae: stadies of zoe and megalope; eats corpses and even shells.

Population trends: On the Romanian Black Sea littoral abundant in the past, still frequent up to 1980; a small number of individuals were found on the southern littoral zone in the period 1980-1993 (in 1993 - 40 ind/m2 in superior infralittoral Eforie North - Mangalia zone).

Threats: Coastal terrigenous pollution by hydrotechnical works.

Conservation measures taken: Included in the Red Data Book of Ukraine, 1994.

Conservation measures proposed: Artificial reefs to increase biofiltration and reduce turbidity.

References:

  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, 1954 - The influence of the severe winter of 1954 on the Black Sea ecosystem and fisheries.( in Rom.) Bull. Ins. Cerc. P.S.C. 1954, 4: 5-12.
  5. Bacescu M., Dumitrescu E., Marcus A., Palladian G.et 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.
  6. Bacescu M. 1967 - Fauna RSR (DECAPODA), 4, 9: 7-335.
  7. Bacescu M., G.I. Muller., M-T Gomoiu, 1971 - Ecologie marina (Marine Ecology), IV:7-274.
  8. Gutu Modest, 1980 - Recent changes in the Decapod fauna of the Romanian Black Sea littoral. Trav. Mus. Hist. Nat “Gr. Antipa”, 21,103-110.
  9. Chervona Knyga Ukrayiny (Red Data Book of Ukraine). Kijiv: Ukrajinska enciklopediya Publ., 1994. p. 51 (in Ukrainian).

Compiled by: C.Dumitrache