Trachythyone Studer, 1876

Thandar, Ahmed S., 2013, Trachythyone flaccida, a new sea cucumber species from southern Angola (Echinodermata: Holothuroidea: Dendrochirotida: Cucumariidae) with key to the genus, Zootaxa 3693 (3), pp. 395-400 : 396

Genus Trachythyone Studer, 1876

Diagnosis (amended from O’Loughlin & O’Hara, 1992). Tentacles 10, ventral two reduced; tube feet restricted to radii or scattered, at least dorsally; calcareous ring simple, without posterior prolongations, plates anteriorly extended, notched posteriorly; body wall ossicles comprising a superficial layer of cups and a deeper layer of perforated plates; cups shallow or deep with usually a spinous or knobbed rim and a 4–8 holed base which may also be spinous, cups sometimes reduced or appear as X-shaped deposits which are often present in addition to complete baskets; plates usually large, smooth or slightly knobbed and single-layered, up to 1 mm in length; tube feet and tentacles with perforated rods and/or plates; end-plates usually present.