DOI: 10.1016/j.quascirev.2015.12.011
Scopus记录号: 2-s2.0-84952929112
论文题名: Is the "Genyornis" egg of a mihirung or another extinct bird from the Australian dreamtime?
作者: Grellet-Tinner G. ; Spooner N.A. ; Worthy T.H.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2016
卷: 133 起始页码: 147
结束页码: 164
语种: 英语
英文关键词: Australia
; Dromornithids
; EBSD
; Eggs
; Eggshells
; Genyornis newtoni
; Megapodes
; Micro-CT
; Paleoenvironments
; Progura
; Quaternary
Scopus关键词: Chemical compounds
; Computerized tomography
; Australia
; Dromornithids
; EBSD
; Eggs
; Eggshells
; Genyornis newtoni
; Megapodes
; Micro CT
; Paleoenvironments
; Progura
; Quaternary
; Birds
; Anseriformes
; Aves
; Dromornithidae
; Galliformes
; Genyornis
; Genyornis newtoni
; Macrocephalon maleo
; Megapodiidae
英文摘要: The iconic Australian Genyornis newtoni (Dromornithidae, Aves) is the sole Pleistocene member of an avian clade now hypothesized to be alternatively in Anseriformes or the sister group of crown Galloanseres. A distinctive type of fossil eggshell commonly found in eroding sand dunes, has been referred to Genyornis newtoni since the 1980s. The 126 by 97 mm Spooner Egg, dated at 54.7 ± 3.1 ka by optical dating of its enclosing sediments, is a complete specimen of this eggshell type that was reconstructed from fragments of a broken egg. We show that the size of the eggs from which this '. Genyornis' eggshell derives, either as predicted from measurements of fragments, or as indicated by the Spooner Egg, is unexpectedly small given the size of G. newtoni, which has an estimated mass of 275 kg, or about seven times the mass of the emu that has a similar sized egg. We compared the microstructure of the putative Genyornis eggshell to that of other dromornithids and a range of galloanseriform taxa using several microcharacterisation techniques. The '. Genyornis' eggshell displays a mosaic of oological characters that do not unambiguously support referral to any known modern bird. Its shell structure, coupled with chemical compounds in the accessory layer, makes it unlikely to have been laid by a dromornithid, whereas several characters support a megapode origin. A potential candidate for the bird that laid the putative '. Genyornis' eggs in the Pleistocene fossil avifaunal record has been ignored: Progura, a genus of extinct giant megapodes, whose species were widespread in Australia. Regression of egg size of megapodes and body mass shows that the Spooner Egg approximates the expected size for eggs laid by species of Progura. We advance the suggestion that the fossil eggshell hitherto referred to Genyornis newtoni, is more likely to have been laid by species of the giant extinct Progura. As megapodes, the species of Progura were obligate ectothermic incubators, which we suggest laid their eggs into a hole dug in sand like the modern megapode Macrocephalon maleo, thus explaining the abundant '. Genyornis' eggshell in sand dunes. Referral of this eggshell to Progura means that the fossil record of Genyornis newtoni is limited to bones and the timing of the extinction of this last dromornithid is unknown. In addition, structural similarities of eggshell in megapodes, the putative Genyornis eggshell and dromornithids, raise the possibility that these taxa are phylogenetically more closely related to each other than any is to anseriforms. Specifically, this means that dromornithids might be a sister group to galliforms rather than to or within anseriforms. © 2015 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59700
Appears in Collections: 过去全球变化的重建
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作者单位: School of Biological Sciences, Flinders University, GPO 2100, Adelaide, SA, Australia; Orcas Island Historical Museums, USA and Investigador Correspondiente of CONICET, Anillaco, Argentina; Institute for Photonics and Advanced Sensing and School of Physical Sciences, University of Adelaide, AdelaideSA, Australia; DST Group, Adelaide, SA, Australia
Recommended Citation:
Grellet-Tinner G.,Spooner N.A.,Worthy T.H.. Is the "Genyornis" egg of a mihirung or another extinct bird from the Australian dreamtime?[J]. Quaternary Science Reviews,2016-01-01,133