Family Sclerothyonidae Thandar, 1989

Remarks. This taxon, erected as Sclerothyoninae by Thandar (1989) within the family Sclerodactylidae, was raised to full family rank by Smirnov (2012) in his revision of the classification of the Holothuroidea . Although not totally accepted by WoRMS (accessed May 2012), it is listed as an alternative nomen.

Diagnosis. [from Thandar 1989, as amended by Martins & Tavares 2019]. Tentacles 10, ventral-most two much reduced. Calcareous ring not tubular, radial and interradial plates separate or united at base only. Posterior paired processes of radial plates long, 2–8 times the length of ring, either entire of broken into several pieces.

Included genera. Sclerothyone (type genus), Temparena Thandar, 1989, Neopentamera Deichmann, 1941, Thandarum Martinez & Brogger, 2012, and Paulayellus Martins & Tavares,. 1998.