Benthic foraminifers from lower Albian black shales (Site 1049, ODP LEG 171): Evidence for a non "uniformitarian" record

A comparison of benthic foraminifers from lower Albian black shales at Ocea n Drilling Program Site 1049 with modern and Mesozoic high carbon flux/low oxygen assemblages indicate that no preferential test shape characterizes b enthic foraminifers from dysaerobic environments, as almost the entire spec trum of test morphologies is represented within these assemblages. The lowe r Albian benthic foraminiferal assemblages from Site 1049 are the first bla ck shale assemblages to be dominated by Fursenkoina viscida, Ellipsoidella cuneata, Pleurostomella reussi and Osangularia schloenbachi all members of the suborder Rotaliina. Thus, early Albian black shale assemblages differ m arkedly from Aptian and Jurassic assemblages dominated mainly by representa tives of the suborders Textulariina and Lagenina. Members of the suborder R otaliina continued to radiate profusely during the Late Cretaceous and Ceno zoic, eventually giving rise to a large proportion of the modern fauna, inc luding many of the high productivity/low oxygen taxa. There is no evidence for a progressive morphological adaptation to low oxygen with time.