Mineralized soft-tissue structure and chemistry in a mummified hadrosaur from the Hell Creek Formation, North Dakota (USA)

Abstract

An extremely well-preserved dinosaur (Cf. Edmontosaurus sp.) found in the Hell Creek Formation (Upper Cretaceous, North Dakota) retains soft-tissue replacement structures and associated organic compounds. Mineral cements precipitated in the skin apparently follow original cell boundaries, partially preserving epidermis microstructure. Infrared and electron microprobe images of ossified tendon clearly show preserved mineral zonation, with silica and trapped carbon dioxide forming thin linings on Haversian canals within apatite. Furthermore, Fourier transform infrared spectroscopy (FTIR) of materials recovered from the skin and terminal ungual phalanx suggests the presence of compounds containing amide groups. Amino acid composition analyses of the mineralized skin envelope clearly differ from the surrounding matrix; however, intact proteins could not be obtained using protein mass spectrometry. The presence of endogenously derived organics from the skin was further demonstrated by pyrolysis gas chromatography mass spectrometry (Py-GCMS), indicating survival and presence of macromolecules that were in part aliphatic (see the electronic supplementary material).

Microscopic and immunohistochemical analyses of the claw of the nesting dinosaur, Citipati osmolskae

“…The composition and structure of beta-keratin suggest that it may persist in fossil material [25][26][27][28][29][30]. Furthermore, because this protein is not found in humans and is vertebrate specific; its identification eliminates the alternative hypotheses of human or microbial contamination, and when used with adequate controls is a good indicator of endogeneity.…”

A snapshot into the terrestrial ecosystem of an exceptionally well-preserved dinosaur (Hadrosauridae) from the Upper Cretaceous of North Dakota, USA

“…The completeness of the specimen indicates that it has not been subjected to any significant transport and the high fidelity preservation further indicates rapid post-mortem burial (Manning et al, 2009). Thus the palynomorphs preserved in the sediments encasing the hadrosaur reflect the regional vegetation at the immediate time of deposition (Fig.…”

“…The specimen was excavated from a 6 m-thick unit of sandstone representing the lateral accretion of a large point-bar. Soft tissue is preserved in siderite and manganese-rich calcium carbonate (Manning et al, 2009) and the specimen consists of an articulated individual, with three-dimensional integument (Fig. 2B) encasing at least one arm and hand, both feet, legs, and tail.…”

“…Herein we analyze the palynological assemblage of a fluvial sandstone, from the lower third of the Hell Creek Formation, encasing the exceptionally well preserved specimen of Edmontosaurus annectens (specimen MRF-03) with the specific aim of reconstructing the local vegetation and paleoenvironment of this particular site. This hadrosaur specimen was selected as it is extremely well-preserved (Manning et al, 2009), and thus represents a unique window in time for paleoenvironmental reconstruction.…”

Exceptionally preserved fossil assemblages through geologic time and space

“…1) -represent a critical resource for studying the ancient biosphere. Fossils of this type include some of the earliest organisms on Earth (Knoll, 1985) as well as remains of integuments (Manning et al, 2009;Navalón et al, 2015), exoskeletons (McNamara et al, 2012a), feathers (Colleary et al, 2015), eyes (Lee et al, 2011), muscles (Martill, 1990), "jellies" (Chen et al, 2007;Stanley and Sturmer, 1987), internal organs (Zhang et al, 2015), nerves (Yang et al, 2016), cells (Xiao et al, 1998), and sub-cellular structures , which offer many opportunities for work on anatomy, physiology, and systematics. Furthermore, geologic deposits containing exceptionally-preserved fossils-such as certain Konservat-Lagerstätten (Seilacher, 1970)-offer relatively complete snapshots for exploring the ecology and dynamics of ancient ecosystems, as they generally contain remains of both biomineralizing and non-mineralizing taxa (Conway Morris, 1986).…”