gemmation

Perifrontal Forms of the Late Cretaceous Modular Hexactinellids (Porifera)

Certain tendencies are supposed to show up in morphogenesis of the Late Cretaceous skeletal sponges, hexactinellids; those tendencies make it possible to distinguish some forms of diverse-level modular organization among the unitary representatives of the group. Generation of primitive ≪modular≫ forms, defined as the perifrontal ones, is associated with incomplete gemmation and isolation of solitary cross canals, apo- or prosochetes

Autonomous Forms of the Late Cretaceous Modular Hexactinellids (Porifera)

Authors: Pervushov E. M.

In morphogenesis of the Late Cretaceous skeletal sponges – hexactinellids – certain tendencies may be traced that allow to distinguish forms of diverse levels of modular organization (≪polyoscula≫ sponges) among the unitary representatives of the group. Skeletons of the sponges from the primary level of modular forms, autonomies, represent an example of the initial module polymerization, with the principal polymerization mechanism involving diverse variants of gemmation and/or fission