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Reproductive cycles, larval mortality and population dynamics of a Late Cretaceous hippuritid association: a new approach to the biology of rudists based on quantitative three-dimensional analysis

✍ Scribed by Stefan Götz; Wolfgang Stinnesbeck


Publisher
John Wiley and Sons
Year
2003
Tongue
English
Weight
437 KB
Volume
15
Category
Article
ISSN
0954-4879

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✦ Synopsis


Abstract

Late Cretaceous rudist bivalves have been well studied in terms of taxonomy, stratigraphy and sedimentological context, but their palaeobiological aspects are poorly known and important questions remain unanswered such as those relating to reproduction and population dynamics. The analysis of a three‐dimensional high‐resolution dataset allowed a detailed evaluation of the ecology and population dynamics of the rudist Hippuritella vasseuri (Douvillé). Our research demonstrates that significant turnover of generations and a stable packing rate characterizes stable and healthy ecological conditions whereas decreasing packing rate, increasing larval mortality and the arrival of non‐hippuritid organisms characterize an association in decline. H. vasseuri reproduced in a cyclical (annual or biannual) pattern, as shown in vertical projection by five equidistant peaks of larval recruitment density within 60 mm of section. Survival chances of rudist larvae appear to have been unrelated to initial available space for settling but are favoured by subsequent increasing space and a low number of coeval competitors.