Spatangoida

The order of the Spatangoidea belongs to the echinodermatous junction of the S.

Morphology

The spatangoïdes (sea-potatoes or heart sea-urchins) have a body ovoidal; their face aborale is convex and their oral, plane face. The prickles are often long and of morphology very varied according to their localization on the body.

Medium of life

They live hidden in the sediments and some as Echinocardium cordatum builds burrows. The depth and the structure of the burrow vary according to the species. The wall of the burrow is consolidated thanks to the mucus secreted by specialized prickles (Clavules) and with the ramming of the wall by the whole of the body prickles.

Food

These echinodermatous S belongs to the Atelostomata, they feed by introducing in a massive way the sediment of which it exploits the organic portion (the Biofilm). Podions péribuccaux digities (phyllopodous) take the sediments located vis-a-vis the mouth. At the species living in a burrow, sediments of surface and thus rich in organic matter, are conveyed until the bottom of the burrow by the means of the respiratory chimney and the former gutter ambulacraire.

Respiratory current

The animal one generates a water current on the surface of its body, current whose important role is respiratory. The current is created by ciliature of the clavules (at the same time glandular and ciliés prickles) grouped in narrow bands (Fasciole) whose layouts occupy of the apical areas, ambitales or posterior of the body of the sea urchin.

Water circulates of the surface of the sediments towards the sea urchin by borrowing the respiratory chimney at Echinidea which form a burrow or while percolant between the grains of sand at the others. The currents are centrifugal on the face aborale; there they circulate more particularly along the side ambulacres (former and posterior) which shelter podions them respiratory. On the oral face, the currents to some extent centripetal and the other are directed subsequently.

List families

According to ITIS:
  • sub-order Asterostomatina
    • family Asterostomatidae
  • sub-order Hemiasterina A.G. Fischer, 1966
    • family Aeropsidae
    • family Hemiasteridae Clark, 1876
    • family Palaeostomatidae
    • family Pericosmidae
    • family Schizasteridae Lambert, 1905
  • sub-order Holasterina
    • family Calymnidae
    • family Holasteridae
    • family Pourtalesiidae
    • family Urechinidae
  • sub-order Micrasterina A.G. Fischer, 1966
  • sub-order Neolampadoida
    • family Neolampadidae
  • sub-order Toxasterina
    • family Toxasteridae

External references

Random links:Ernie Fletcher | Seattle Sounders | List publications by editors - Winds of West - 0/9 | Mariusz Fyrstenberg | George Smiley | Tamaroa_(tribu)