MODES OF REPRODUCTION IN RECENT AND FOSSIL CUPULADRIID BRYOZOANS

摘要: Cupuladriid cheilostome bryozoans can make new colonies both sexually and asexually. Sexual (aclonal) are derived from larvae while asexual (clonal) col- onies result the fragmentation or division of larger colonies. A number specialised morphologies exist which either enhance discourage clonality, cupuladriids preserve these in their skeletons, meaning that it is possi- ble to count abundances individual modes repro- duction fossil assemblages, thus measure mode tempo evolution life histories using colo- nies. In this paper we categorise, illustrate describe various clonal aclonal methods propagation through Cenozoic. reproduction only method propagation, four described comprising: (1) mechanical frag- mentation, (2) autofragmentation, (3) colonial budding (4) peripheral fragmentation. The processes involved each discussed explain how prevalence be measured record preservable morphologies. Compiling a occurrence distribution time space discover general trend towards more complex all three cupuladriid gen- era, but geologically recent extinction some has left present-day assemblage rela- tively depauperate. We see striking similarities timing expansion between two most important genera, Cupuladria Discoporella, although clear Discoporella evolved much wider range special clonality than did Cupuladria.