Protencrinidae Knapp, 1969

Family Protencrinidae Knapp, 1969 Genus Protencrinus Jaekel, 1918

Type species: Protencrinus moscoviensis Jaekel, 1918 ; Pennsylvanian (Moscovian), Russia .

Included species: Protencrinus atoka ( Strimple, 1961) ; Protencrinus baliensis Webster, 2012b ; Protencrinus lobatus Yakovlev, 1948 ; Protencrinus moscoviensis Jaekel, 1918 ; Protencrinus mutabilis Knapp, 1969 ; Protencrinus ? sp. indet. in Hashimoto, 1984.

Remarks. —Sutural contact between the infrabasal plates with radial plates is a very unusual character in crinoids. This character is present on all rays or present in some rays in all species of Protencrinus . It also occurs in one species of Prolobocrinus , i.e., P. striatus Wanner, 1937 . Protencrinus and Prolobocrinus are distinguished by, among other things, the height of the crown, morphology of the radial facets, the size and position of the basal and radial plates, the aboral cup plate sculpturing, and the anal sac.

At present five Protencrinus species are named, and one species indeterminate is designated. Species of Protencrinus are differentiated on the basis of outline of the aboral cup in oral view, relative depth of the basal concavity, presence and/or absence of sutural contact between the infrabasal circlet and radial plate (and following whether basal plates are separated laterally), if present the relative width of the infrabasal sutural contact between the infrabasal plate and radial plate, and relative size of the basal plates.

Stratigraphic and geographic range. —Lower Permian, Crete ( Greece), West Timor; Permian, Cisuralian, Artinskian, Slovenia.