Echinodermata: Holothuroidea  -  sea cucumbers

Large holothurians, in particular tropical species, are not easily confused with polychaetes since their radial symmetry, tube feet and oral tentacles are sufficiently distinctive. However, small apodous holothurians (such as the one illustrated on this page) are widespread in temperate environments. Lacking tube feet, apodous holothurians may not be recognised initially as holothurains. However, the oral tentacles, if everted, are distinctive and unlike anything in the polychaetes. The soft, fragile body of apodous holothurians often has a "sticky" feel, due to the minute hook-shaped ossicles.

Over 1,400 species of holothurians are known world-wide. The Australian fauna, when catalogued in 1995, comprised fifteen families, 69 genera and 211 species, although additional cryptic species of small apodous holothurians continue to be recognised from temperate Australian environments. Accurate identification of echinoderms will require dissection, and examination of ossicles. Since the ossicles dissolve readily, holothurians which have been fixed in formalin are often unidentifiable.

References

Rowe and Gates (1995) exhaustively list the then known Australian fauna and its literature. Edgar (1997), Shephard & Thomas (1982) and the Marine Research Group's 1984 Coastal Atlas introduce the southern Australian holothurian fauna. Shephard & Thomas (1982) describe study methods.