Family ENTAPIIDAE Dumitrica in De Wever, Dumitrica, Caulet, Nigrini & Caridroit, 2001

Entapiidae Dumitrica in De Wever, Dumitrica, Caulet, Nigrini & Caridroit, 2001: 118-119.

Entapiinae – Afanasieva et al. 2005: 273. — Afanasieva & Amon, 2006: 110.

TYPE GENUS. — Entapium Sanfilippo & Riedel, 1973: 491 [type species by original designation: Entapium regulare Sanfilippo & Riedel, 1973: 492]

INCLUDED GENUS. — Entapium Sanfilippo & Riedel, 1973: 491.

DIAGNOSIS. — Skeleton consists of two shells. The innermost shell has a pyriform shape and the outer shell is latticed and spherical. Three to six radial bladed beams penetrate the outer shell to form bladed radial spines. No fine radial beams were observed.

STRATIGRAPHIC OCCURRENCE. — Middle Paleocene-early Middle Eocene.

REMARKS

The internal skeletal structure for Entapium was illustrated (Nakaseko & Nishimura 1982: pl. 22, fig. 6?; Nishimura 2001; pl. 1, fig. 13; Sanfilippo & Riedel 1973: pls 23, 24). However, Entapium showed an outward migration of the medullary shell towards the cortical shell which ultimately tends to disappear. O’Connor (1999) coined the new genus name Zealithapium but this latter genus is not an Entapiidae. The numerous radial spines similar to those of Stylosphaeridae morphotypes were observed, but the characteristics of these radial spines are different between the two families.