The old and the new plankton: ecological replacement of associations of mollusc plankton and giant filter feeders after the Cretaceous?

PeerJ

article

Amane Tajika¹  Alexander Nützel²  Christian Klug¹ 

[1] Paläontologisches Institut und Museum, Universität Zürich;SNSB-Bayerische Staatssammlung für Paläontologie und Geologie, Department of Earth and Environmental Sciences, Palaeontology & Geobiology, GeoBio-Center LMU

关键词: Belemnitida;    Ammonoidea;    Cretaceous;    Fecundity;    Palaeogene;    Filter feeders;    Holoplanktonic gastropoda;    Pachycormiformes;    Mass extinctions;   

DOI  :  10.7717/peerj.4219

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Owing to their great diversity and abundance, ammonites and belemnites represented key elements in Mesozoic food webs. Because of their extreme ontogenetic size increase by up to three orders of magnitude, their position in the food webs likely changed during ontogeny. Here, we reconstruct the number of eggs laid by large adult females of these cephalopods and discuss developmental shifts in their ecologic roles. Based on similarities in conch morphology, size, habitat and abundance, we suggest that similar niches occupied in the Cretaceous by juvenile ammonites and belemnites were vacated during the extinction and later partially filled by holoplanktonic gastropods. As primary consumers, these extinct cephalopod groups were important constituents of the plankton and a principal food source for planktivorous organisms. As victims or, respectively, profiteers of this case of ecological replacement, filter feeding chondrichthyans and cetaceans likely filled the niches formerly occupied by large pachycormid fishes during the Jurassic and Cretaceous.

【 授权许可】

CC BY