气候变化领域集成服务门户(CCPortal): Insect trace fossils elucidate depositional environments and sedimentation at a dinosaur nesting site from the Cretaceous (Campanian) Two Medicine Formation of Montana

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DOI	10.1016/j.palaeo.2019.109262
	Insect trace fossils elucidate depositional environments and sedimentation at a dinosaur nesting site from the Cretaceous (Campanian) Two Medicine Formation of Montana
	Freimuth W.J.; Varricchio D.J.
发表日期	2019
ISSN	0031-0182
卷号	534
英文摘要	We describe the diversity and abundance of insect (specifically hymenopterans and coleopterans) pupation structures in the Upper Cretaceous (Campanian) Two Medicine Formation at the Egg Mountain locality, western Montana, U.S.A., an important dinosaur nesting site. The study interval comprises a massive calcareous siltstone and indurated silty limestone horizons interpreted as the product of cumulative paleosols. A 7 m by 11 m area was quarried with a jackhammer at intervals of 12.5 cm thickness for a 1.5 m thick stratigraphic section. The ichnoassemblage comprises four morphotypes (small, medium, large, and wide) assigned to Fictovichnus sciuttoi, of which three represent wasp (hymenopteran) cocoons while the fourth (wide) type potentially was produced by a coleopteran. Medium and small F. sciuttoi are dominant while large and wide Fictovichnus are less common and absent in some sample intervals. Other probable insect traces include partial perforations in cocoons (Tombownichnus), isolated burrows, and an enigmatic hemispherical trace. Material is representative of a depauperate Celliforma ichnofacies. Pervasive cocoons and other traces throughout the sequence suggest persistent soil conditions suitable for insect nesting and pupation, and suggest an absence of sediment pulses of sufficient thickness to prohibit thorough colonization. Peaks in pupation chamber abundance may reflect episodes of reduced sedimentation rates otherwise unseen in the absence of primary bedding structures. Well-drained and friable soil conditions favorable for insect nesting also may help explain the abundance of dinosaur nests and other vertebrate nesting events in associated strata as well as the presence of small terrestrial forms. © 2019 Elsevier B.V.
英文关键词	Coleopterans; Egg Mountain; Hymenopterans; Ichnology; Pupichnia
语种	英语
scopus关键词	calcareous soil; Cretaceous; depositional environment; dinosaur; ichnology; limestone; nest site; paleoecology; sedimentation; siltstone; trace fossil; wasp; Egg Mountain; Montana; United States; Celliforma; Coleoptera; Dinosauria; Hexapoda; Hymenoptera; Vertebrata
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150810
作者单位	Department of Earth Sciences, Montana State University, 226 Traphagen Hall, PO Box 173480, Bozeman, MT 59717, United States
推荐引用方式 GB/T 7714	Freimuth W.J.,Varricchio D.J.. Insect trace fossils elucidate depositional environments and sedimentation at a dinosaur nesting site from the Cretaceous (Campanian) Two Medicine Formation of Montana[J],2019,534.
APA	Freimuth W.J.,&Varricchio D.J..(2019).Insect trace fossils elucidate depositional environments and sedimentation at a dinosaur nesting site from the Cretaceous (Campanian) Two Medicine Formation of Montana.Palaeogeography, Palaeoclimatology, Palaeoecology,534.
MLA	Freimuth W.J.,et al."Insect trace fossils elucidate depositional environments and sedimentation at a dinosaur nesting site from the Cretaceous (Campanian) Two Medicine Formation of Montana".Palaeogeography, Palaeoclimatology, Palaeoecology 534(2019).