Australian Cenozoic Bryozoa, 2: Free-living Cheilostomata of the Eocene St. Vincent Basin,S.A., including Bonellina gen. nov

Schmidt, R., March 2007. Australian Cenozoic Bryozoa, 2: Free-living Cheilostomata of the Eocene St. Vincent Basin, S.A., including Bonellina gen. nov. Alcheringa 31, 67-84. ISSN 0311-5518.

Free-living bryozoans are diverse in the Eocene sediments of the St. Vincent Basin, South Australia. They include Bonellina pentagonalis gen. et sp. nov., Otionellina sp. cf. O. exigua (Tenison Woods), Otionellina sp. cf. O. cupola (Tenison Woods), Tubiporella magna (Tenison Woods), Celleporaria nummularia (Tenison Woods), and an indeterminate species only found as moulds. This diversity and abundance is highest in the sediments representing the initial transgressive marine facies, where they occur in ‘sand fauna’ bryozoan assemblages (e.g. with Melicerita and Siphonicytara). Free-living bryozoans decrease up-section and are absent from latest Eocene sediments, indicating a significant environmental shift.

Rolf Schmidt [rschmid@museum.vic.gov.au], Museum Victoria, Melbourne, Vic 3001, Australia; received 18.3.2005, revised 14.12.2005.