Pinnotheridae

Of the Pinnotheridae (of Haan 1883) includes/understands 252 S and according to the researchers of 26 with nearly 54 S. This family sets up a group Polyphylétique requiring an important revision.

This family presents a world distribution and finds itself in the Atlantic Oceans, the Pacific and Indien. Nevertheless no species was recorded in the polar regions of the sphere.

General biology

The very great majority of the species of Pinnotheridae is symbiotic marine invertebrates.

The hosts are varied:

  • Annélides

  • Echiurien S
  • Siponculien S
  • Arthropod S (digger shrimps)
  • Mollusc S (Bivalvular S, Gastropodous S, Polyplacophore S)
  • Echinodermatous S (Astérie S, Sea cucumber S, Sea urchin S)
  • Urochordé S (Ascidie S)

Their symbioses are obligatory or optional and with more or less high degrees of specificity. Lastly, on their host, the Crabe S are either solitary or with several. The evolutionary tendencies within this family are:

  1. the passage of a free form of life towards a symbiotic and obligatory form of life,
  2. a diversification of the species hosts used.

The members of this family are always small compared to other brachyoures with a width of the not exceeding céphalothorax, on average, 1cm. The English vernacular name of these shellfish is “pea crab” (crab “garden pea”) in connection with their small size and the round shape of the body, illustrated well by the case of Pinnotheres pisum which is found in the moulds ( Mytilus edulis ).

According to the species, the abdomen of the males includes/understands, behind Telson, either the 6 traditional segments or a more reduced number due to fusion of certain segments. The abdomen of the females is extremely developed compared to that of the males with an important going beyond on the sides and behind of the Céphalothorax; it is thus quite visible in dorsal sight. This widening of the abdomen increases the capacity of the incubating cavity. The females are generally, but not systematically, taller than the males.

Food behavior

In general, these crabs are microphages and nourish mucus produced by the host; they can also use the respiratory currents maintained by their hosts and recover food particles and micro-organisms. However, of the species of the Dissodactylus kind which parasitize sea urchins partly nourish prickles of their hosts. They divide the prickles using their grips and cause lesions on the surface of the sea urchin. The food behavior of Dissodactylus is still ignored.

Reproduction and vital cycle

Of share the world distribution of the kinds, it is difficult to generalize the periods of layings and reproduction of the members of this family. In the tropical and subtropical areas, the species of Pinnotheridae present a continuous reproduction with nevertheless increases in the production of larvae to certain periods LED' year.

The number of eggs produced by brooded is excessively tiny room compared to the other members of the Brachyoures. This difference is explained, partly, by the size of the crabs which belong to the smallest species of Brachyoures and by the limited space of the incubating room in the females.

There is from 3 to 5 stages Zoés and the intermediate duration of the larval development is of 40 ± 6 days by including the stage Mégalope, value very close to what is observed at the others Brachyoures. Certain species of Pinnotheridae make exception to the rule, for example Tunicotheres moseri .

List kinds

  • Abyssotheres
  • Afropinnotheres
  • Alainotheres
  • Alarconia
  • Anomalifrons
  • Aphanodactylus
  • Arcotheres
  • Asthenognathus
  • Austinixa
  • Austinotheres
  • Buergeres
  • Calyptraeotheres
  • Chasmocarcinops
  • Clypeasterophilus
  • Dissodactylus
  • Durckheimia
  • Epulotheres
  • Ernestotheres
  • Fabia
  • Gemnotheres
  • Hapalonotus
  • Holotheres
  • Holothuriophilus
  • Hospitotheres
  • Juxtafabia
  • Limotheres
  • Mortensenella
  • Nannotheres
  • Nepinnotheres
  • Opisthopus
  • Orthotheres
  • Ostracotheres
  • Parapinnixa
  • Pinnaxodes
  • Pinnixa
  • Pinnotherelia
  • Pinnotheres
  • Pseudopinnixa
  • Raymondia
  • Sakaina
  • Scleroplax
  • Serenotheres
  • Sindheres
  • Tetrias
  • Tridacnotheres
  • Tritonynamia
  • Tumidotheres
  • Tunicotheres
  • Viridotheres
  • Voeltzkowia
  • Waldotheres
  • Xanthasia
  • Xenophtalmus
  • Zaops

According to ITIS

  • super-family Pinnotheroidea
    • family Pinnotheridae
      • kind Aphanodactylus Tesch, 1918
      • kind Austinixa Heard and Manning, 1997
      • kind Clypeasterophilus Campos and Griffith, 1990
      • kind Dissodactylus Smith, 1870
      • kind Fabia Dana, 1851
      • kind Gemmotheres Campos, 1996
      • kind Opisthopus Rathbun, 1893
      • kind Orthotheres Sakai, 1969
      • kind Parapinnixa Holmes, 1894
      • kind Pinnaxodes Heller, 1865
      • kind Pinnixa White, 1846
      • kind Pinnotheres Latreille, 1802
      • kind Scleroplax Rathbun, 1893
      • kind Tumidotheres Campos, 1989
      • kind Tunicotheres Campos, 1996
      • kind Zaops Rathbun, 1900

External bonds

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