Evidence of preserved collagen in an Early Jurassic sauropodomorph dinosaur revealed by synchrotron FTIR microspectroscopy

Abstract

Fossilized organic remains are important sources of information because they provide a unique form of biological and evolutionary information, and have the long-term potential for genomic explorations. Here we report evidence of protein preservation in a terrestrial vertebrate found inside the vascular canals of a rib of a 195-million-year-old sauropodomorph dinosaur, where blood vessels and nerves would normally have been present in the living organism. The in situ synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectra exhibit the characteristic infrared absorption bands for amide A and B, amide I, II and III of collagen. Aggregated haematite particles (α-Fe2O3) about 6∼8 μm in diameter are also identified inside the vascular canals using confocal Raman microscopy, where the organic remains were preserved. We propose that these particles likely had a crucial role in the preservation of the proteins, and may be remnants partially contributed from haemoglobin and other iron-rich proteins from the original blood.

Chemical evidence of preserved collagen in 54‐million‐year‐old fish vertebrae

“…Recently, Lee et al . () reported the preservation of collagen in an Early Jurassic sauropodomorph dinosaur using synchrotron FTIR microspectroscopy. FTIR spectroscopic analysis only examines the functional groups present and does not reveal definite chemical structures.…”

Role of Sediment Size and Biostratinomy on the Development of Biofilms in Recent Avian Vertebrate Remains

“…Despite previously proposed alternative hypotheses for the presence of primary soft-tissues in Mesozoic vertebrate fossils, such as contaminants or recent biofilms (Kaye et al, 2008), an abundance of biomolecular evidence has confirmed their initial interpretations as primary soft-tissues (Schweitzer et al, 2005(Schweitzer et al, , 2009(Schweitzer et al, , 2016Asara et al, 2007). Biochemical processes have been proposed to play a significant role in the preservation of soft osteological tissues; recently iron has been suggested as an alternative mechanism to explain the process by which primary soft-tissues can remain pliable over geologic time, by which iron from hemoglobin serves as a natural chelator to increase tissue immunoreactivity in vertebrate remains (Schweitzer et al, 2014;Lee et al, 2017). However, the presence of mineralized biofilms in vertebrate samples were osteological soft-tissues have also been recovered suggests a role in tissue preservation (Briggs, 2003;Peterson et al, 2010;Kremer et al, 2012;Raff et al, 2013Raff et al, , 2014Schweitzer et al, 2016), where biofilm crystallization in Haversian and Volkmann's canals seals natural vectors from further microbial penetration and retards subsequent metabolization of soft-tissues.…”

“…The presence of non-biomineralized osteocytes and blood vessels in vertebrate fossils and sub-fossils from various fluvial deposits has been well-established in literature (Pawlicki, 1978;Schweitzer et al, 2005Schweitzer et al, , 2007Schweitzer et al, , 2016Asara et al, 2007;Bertazzo et al, 2015;Lee et al, 2017). Particles of aggregated hematite have been suggested to play a role in the preservation of collagen in such fossils (Schweitzer et al, 2005(Schweitzer et al, , 2016; Lee et al, 2017).…”

“…Particles of aggregated hematite have been suggested to play a role in the preservation of collagen in such fossils (Schweitzer et al, 2005(Schweitzer et al, , 2016; Lee et al, 2017). Crucially, growth of microbial biofilms, prokaryotic organisms in an exopolymeric matrix (Schweitzer et al, 2016), on the surface of bone and the subsequent sealing of natural osteological vectors like pores of blood vessels and Haversian and Volkmann's canals have been suggested to facilitate the preservational mechanisms that occur during the early phases of diagenesis; biofilm infiltration leads to mineralization, retarding further metabolization of organic materials and promoting soft tissue preservation (Trinajstic et al, 2007;Peterson et al, 2010;Schweitzer et al, 2016).…”

Life Inside a Dinosaur Bone: a Thriving Microbiome

“…ATR FTIR of a HCl demineralised, freeze-dried vessel from subterranean Centrosaurus bone revealed somewhat poorly-resolved, broad organic peaks (Fig. 2C) that were close in position to peaks that might be expected from various CH, CO, and amide bonds, as well as water, phosphate, and potentially carbonate and silicate bonds (Lee et al 2017; also see publicly available NIST libraries). Pleistocene-Holocene shark tooth ( Fig.…”