A giant soft-shelled egg from the Late Cretaceous of Antarctica

doi:10.1038/s41586-020-2377-7

GSTDTAP > 地球科学

DOI	10.1038/s41586-020-2377-7
	A giant soft-shelled egg from the Late Cretaceous of Antarctica
	Lewnard, Joseph A.1,2,3; Lo, Nathan C.4; Arinaminpathy, Nimalan 5; Frost, Isabel 5,6; Laxminarayan, Ramanan 6,7
	2020-06-17
发表期刊	NATURE
ISSN	0028-0836
EISSN	1476-4687
出版年	2020
文章类型	Article;Early Access
语种	英语
国家	USA; Chile
英文关键词	Egg size and structure reflect important constraints on the reproductive and life-history characteristics of vertebrates(1). More than two-thirds of all extant amniotes lay eggs(2). During the Mesozoic era (around 250 million to 65 million years ago), body sizes reached extremes nevertheless, the largest known egg belongs to the only recently extinct elephant bird(3), which was roughly 66 million years younger than the last nonavian dinosaurs and giant marine reptiles. Here we report a new type of egg discovered in nearshore marine deposits from the Late Cretaceous period (roughly 68 million years ago) of Antarctica. It exceeds all nonavian dinosaur eggs in volume and differs from them in structure. Although the elephant bird egg is slightly larger, its eggshell is roughly five times thicker and shows a substantial prismatic layer and complex pore structure(4). By contrast, the new fossil, visibly collapsed and folded, presents a thin eggshell with a layered structure that lacks a prismatic layer and distinct pores, and is similar to that of most extant lizards and snakes (Lepidosauria)(5). The identity of the animal that laid the egg is unknown, but these preserved morphologies are consistent with the skeletal remains of mosasaurs (large marine lepidosaurs) found nearby. They are not consistent with described morphologies of dinosaur eggs of a similar size class. Phylogenetic analyses of traits for 259 lepidosaur species plus outgroups suggest that the egg belonged to an individual that was at least 7 metres long, hypothesized to be a giant marine reptile, all clades of which have previously been proposed to show live birth(6). Such a large egg with a relatively thin eggshell may reflect derived constraints associated with body shape, reproductive investment linked with gigantism, and lepidosaurian viviparity, in which a ' vestigial' egg is laid and hatches immediately(7). A fossil egg unearthed from Cretaceous deposits in Antarctica is more than 20 cm long, exceeds all known nonavian eggs in volume, is soft-shelled, and was perhaps laid by a giant marine lizard such as a mosasaur.
领域	地球科学 ; 气候变化 ; 资源环境
收录类别	SCI-E
WOS记录号	WOS:000541024900007
WOS关键词	LIFE-HISTORY ; CLUTCH MASS ; EVOLUTION ; PRESERVATION ; REPRODUCTION ; CONSTRAINTS ; SIZE
WOS类目	Multidisciplinary Sciences
WOS研究方向	Science & Technology - Other Topics
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引用统计
文献类型	期刊论文
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/276620
专题	地球科学资源环境科学
作者单位	1.Univ Calif Berkeley, Sch Publ Hlth, Div Epidemiol, Berkeley, CA 94720 USA; 2.Univ Calif Berkeley, Sch Publ Hlth, Div Infect Dis & Vaccinol, Berkeley, CA 94720 USA; 3.Univ Calif Berkeley, Coll Engn, Ctr Computat Biol, Berkeley, CA 94720 USA; 4.Univ Calif San Francisco, Dept Med, San Francisco, CA 94143 USA; 5.Imperial Coll London, Sch Publ Hlth, London, England; 6.Ctr Dis Dynam Econ & Policy, New Delhi, India; 7.Princeton Univ, Princeton Environm Inst, Princeton, NJ 08544 USA
推荐引用方式 GB/T 7714	Lewnard, Joseph A.,Lo, Nathan C.,Arinaminpathy, Nimalan,et al. A giant soft-shelled egg from the Late Cretaceous of Antarctica[J]. NATURE,2020.
APA	Lewnard, Joseph A.,Lo, Nathan C.,Arinaminpathy, Nimalan,Frost, Isabel,&Laxminarayan, Ramanan.(2020).A giant soft-shelled egg from the Late Cretaceous of Antarctica.NATURE.
MLA	Lewnard, Joseph A.,et al."A giant soft-shelled egg from the Late Cretaceous of Antarctica".NATURE (2020).