Psolidae Burmeister, 1837

Laguarda-Figueras, Alfredo, 2014, Lissothuria caboblanquensis n. sp., a new species of sea cucumber (Holothuroidea: Dendrochirotida: Psolidae) from Costa Rica, Zootaxa 3802 (1), pp. 144-150 : 145

Family Psolidae Burmeister, 1837

Diagnosis. Dendrochirotida with 10 tentacles, the two ventral ones are often smaller. Body laterally and dorsally covered with large overlapping scales, in some genera some scales are perforated for the passage of the tube feet. Ventral surface lacking scales and modified into a sole. Mouth and anus displaced to dorsal surface and usually covered by large orals or interradials valves. Tube feet on ventral surface arranged in three rows (in genus Psolus midventral row often reduced). Dorsal tube-feet reduced or, in the genus Psolus , completely absent. Calcareous ring without posterior processes. Gonads in two tufts on the dorsal side opening on a papilla behind the tentacles. Ossicles: in some forms, the dorsal external ossicles maybe cups, baskets, hourglass or tower shaped, one of these types may be absent. Dorsal appendages, if present, with or without endplates and supporting rods or plates. In some genus (i. e. Psolus ) there are small knobbed buttons surrounding the periphery of the dorsal scales. Some genus doesn’t have any ossicles in the outside of the dorsal scales. In the sole, perforated plates or buttons, smooth or knobbed; mono- and multi-layered plates, baskets and ball-like laced ossicles formed by developing of additional cross-bars and processes on the plate surface. Feet with end plates and a varying number of supporting rods or plates. Tentacles with or without perforated plates or rods, some forms possess few rosettes. Sometimes the ossicles disappear in older individuals.