Were Late Cretaceous extinctions of gastropods selective by generic longevity?  

作　　者：Dmitry A.Ruban 

机构地区：[1]Division of Mineralogy and Petrography,Geology and Geography Faculty,Southern Federal University

出　　处：《Geoscience Frontiers》2013年第1期87-93,共7页地学前缘（英文版）

摘　　要：Many gastropod taxa went extinct during the Late Cretaceous. The stratigraphic ranges of 268 genera permit to establish the longevity of extinction victims for each stage of this epoch. ＂Young＂ taxa （originated within B epochs before the extinction） prevailed among victims of the extinctions in all stages. The proportion of ＂old＂ taxa （originated before the Cretaceous） that went extinct was the highest in the Cenomanian, and it was the lowest in the Coniacian and the Maastrichtian. It appears that the end-Cretaceous mass extinction affected chiefly ＂young＂ taxa. However, the comparison with the earlier time intervals suggests that this pattern of selectivity by generic longevity was not specific for the noted catastrophe, but, in contrast, it was typical for the entire Late Cretaceous. The latest Cenomanian environmental perturbation （OAE2） caused a stronger extinction of＂old＂ taxa, and thus, this biotic crisis was less selective by generic longevity. This hypothesis, however, is not proven by the statistical test.Many gastropod taxa went extinct during the Late Cretaceous. The stratigraphic ranges of 268 genera permit to establish the longevity of extinction victims for each stage of this epoch. ＂Young＂ taxa （originated within B epochs before the extinction） prevailed among victims of the extinctions in all stages. The proportion of ＂old＂ taxa （originated before the Cretaceous） that went extinct was the highest in the Cenomanian, and it was the lowest in the Coniacian and the Maastrichtian. It appears that the end-Cretaceous mass extinction affected chiefly ＂young＂ taxa. However, the comparison with the earlier time intervals suggests that this pattern of selectivity by generic longevity was not specific for the noted catastrophe, but, in contrast, it was typical for the entire Late Cretaceous. The latest Cenomanian environmental perturbation （OAE2） caused a stronger extinction of＂old＂ taxa, and thus, this biotic crisis was less selective by generic longevity. This hypothesis, however, is not proven by the statistical test.

关 键 词：Gastropods Extinction Longevity Selectivity Late Cretaceous 

分 类 号：Q915[天文地球—古生物学与地层学]