Family PHASELIFORMIDAE Pessagno, 1972

Phaseliformidae Pessagno, 1972: 273; 1976: 26. — Dumitrica 1995: 26-27. — Hollis 1997: 48. — De Wever et al. 2001: 165. — Afanasieva et al. 2005: S281 [in Order Oviformata]. — Afanasieva & Amon 2006: 121.

TYPE GENUS. — Phaseliforma Pessagno, 1972: 274 [type species by original designation: Phaseliforma carinata Pessagno, 1972: 274, pl. 22, fig. 1].

INCLUDED GENUS (CENOZOIC ONLY). — Phaseliforma Pessagno, 1972: 274 .

DIAGNOSIS. — According to De Wever et al. (2001: 165), the family Phaseliformidae is characterized by “ test subellipsoidal, thicker at anterior end than at posterior end. Internal meshwork more or less concentric ”.

STRATIGRAPHIC OCCURRENCE. — Early Hauterivian-Early Paleocene.

REMARKS

The practical internal structure of Phaseliformidae has not been illustrated as of yet. Thus, their taxonomic position tentatively follows that of De Wever et al. (2001: 165). As for Phaseliforma, they appear to belong to the Spongodiscidae, Spongobrachiidae, Spongopylidae or Litheliidae due to the observed presence of spongy structures. However, the molecular phylogenetic study indicates that a spongy structure, in and of itself, should not be a determining factor in defining a single group.