DOI: 10.1016/j.palaeo.2013.06.032
论文题名: Paleoecology of archaeocete whales throughout the Eocene: Dietary adaptations revealed by microwear analysis
作者: Fahlke J.M. ; Bastl K.A. ; Semprebon G.M. ; Gingerich P.D.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 386 起始页码: 690
结束页码: 701
语种: 英语
英文关键词: Carnivory
; Cetacea
; Land-to-sea transition
; Low-magnification microwear
; Piscivory
; Tooth wear
英文摘要: Archaeocete whales originated from within terrestrial artiodactyls around the Paleocene-Eocene boundary and gave rise to modern toothed whales (Odontoceti) and baleen whales (Mysticeti) at the end of the Eocene. The cetacean transition from life on land to life in water is documented by archaeocete fossils reflecting stages of increasing aquatic adaptation throughout the Eocene. During this time, feeding and diet in cetaceans supposedly changed from herbivory or omnivory to piscivory and carnivory. It is still not fully understood whether an early dietary shift was the reason for cetaceans to abandon land, or whether aquatic feeding evolved later, at a semiaquatic stage. To assess archaeocete diet and its evolution through time, we analyzed dental enamel microwear of an early Eocene pakicetid, middle Eocene protocetids, and middle-to-late Eocene basilosaurids. We quantified wear features on shearing facets of upper and lower cheek teeth using low-magnification stereoscopic microwear analysis. Results were compared with the microwear of extant fully-aquatic odontocetes, semiaquatic pinnipeds, and terrestrial carnivores. The microwear of archaeocetes strongly resembles that of modern pinnipeds and, to a lesser extent, odontocetes that include cephalopods, crustaceans, bivalves and gastropods, as well as marine birds and mammals besides fish in their diet. The degree of aquatic adaptation in archaeocetes seems to be reflected in their diet. Aquatic feeding is already indicated for the late early Eocene terrestrial Pakicetus inachus since its microwear already resembles that of the middle Eocene semiaquatic protocetids. Middle-to-late Eocene fully-aquatic basilosaurids turn out to be separated from the protocetids and P. inachus in all parts of the study and apparently ingested more or larger hard items. We conclude that cetaceans were not primarily piscivorous, and that piscivory and carnivory, where present in modern cetaceans, evolved from a very diverse diet in Eocene archaeocetes that included various kinds of invertebrates and vertebrates. Inclusion of mammals in the cetacean diet is not a recent dietary specialization but might be as old as the middle Eocene, implied by a microwear signal in Qaisracetus arifi similar to those of the modern hyena and the killer whale. Consumption of mammal meat was very likely well-established in middle-to-late Eocene forms (heavy gouging and extremely destructive macroscopic wear in Basilosaurus isis). © 2013 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69682
Appears in Collections: 过去全球变化的重建
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作者单位: Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, D-10115 Berlin, Germany; Institut für Paläontologie, Universität Wien, Althanstraße 14, A-1090 Vienna, Austria; HNO-Klinik der Medizinischen Universität Wien, Forschungsgruppe Aerobiologie und Polleninformation, Währinger Gürtel 18-20, A-1090 Vienna, Austria; Department of Biology, Bay Path College, 588 Longmeadow Street, Longmeadow, MA 01106, United States; Museum of Paleontology, University of Michigan, 1109 Geddes Avenue, Ann Arbor, MI 48109-1079, United States
Recommended Citation:
Fahlke J.M.,Bastl K.A.,Semprebon G.M.,et al. Paleoecology of archaeocete whales throughout the Eocene: Dietary adaptations revealed by microwear analysis[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,386