Calescharidae, a new family for the Tertiary to Recent Genera Caleschara MacGillivray and Tretosina Canu and Bassler (Bryozoa: Cheilostomata)

A new family of Cheilostomata, the Calescharidae, is introduced for the genus Caleschara MacGillivray and its Recent Australian typespecies, C. denticulata(MacGillivray), which is redefined from type and other material. The Australian Tertiary genus Tretosina Canu & Bassler and its type species,T. arcifera Canu & Bassler, are closely related,and are also assigned to the Calescharidae. The history and significance of family attributions of both genera are outlined, and RecentC. denticulata from Australian and other localities is distinguished from the Late Tertiary Victorian species C. parva Maplestone. Caleschara lithconis, sp. nov., from the Late Eocene of Victoria is one of the earliest known species: its morphology closely resembles a Recent form from the Philippines, C. junctifera Canu & Bassler. Another Recent species, Caleschara minuta (Maplestone) from the GilbertIslands, is a senior synonym of three other Indo-Pacific species,C. levinseni Harmer, C. laxa Canu & Bassler and Floridinella arculifera Canu & Bassler, and resembles the European Paleocene C. squamosa. Three other related species are briefly discussed. Close relationships to other families are problematic and are discussed; divergence in the early history of the cheilostomes is inferred.