Soft tissue and cellular preservation in vertebrate skeletal elements from the Cretaceous to the present

Abstract

Soft tissues and cell-like microstructures derived from skeletal elements of a well-preserved Tyrannosaurus rex (MOR 1125) were represented by four components in fragments of demineralized cortical and/or medullary bone: flexible and fibrous bone matrix; transparent, hollow and pliable blood vessels; intravascular material, including in some cases, structures morphologically reminiscent of vertebrate red blood cells; and osteocytes with intracellular contents and flexible filipodia. The present study attempts to trace the occurrence of these four components in bone from specimens spanning multiple geological time periods and varied depositional environments. At least three of the four components persist in some skeletal elements of specimens dating to the Campanian. Fibrous bone matrix is more altered over time in morphology and less likely to persist than vessels and/or osteocytes. Vessels vary greatly in preservation, even within the same specimen, with some regions retaining pliability and other regions almost crystalline. Osteocytes also vary, with some retaining long filipodia and transparency, while others present with short and stubby filipodia and deeply pigmented nuclei, or are pigmented throughout with no nucleus visible. Alternative hypotheses are considered to explain the origin/source of observed materials. Finally, a twopart mechanism, involving first cross-linking of molecular components and subsequent mineralization, is proposed to explain the surprising presence of still-soft elements in fossil bone. These results suggest that present models of fossilization processes may be incomplete and that soft tissue elements may be more commonly preserved, even in older specimens, than previously thought. Additionally, in many cases, osteocytes with defined nuclei are preserved, and may represent an important source for informative molecular data.

Biologically and diagenetically derived peptide modifications in moa collagens

“…Cortical bone fragments from an indeterminate moa specimen (MOR OST-255; 800-1000 years old [24]) were extracted as described by Cleland et al [23]. Briefly, approximately 1 g of cortical bone was demineralized in 9 ml 0.6 M HCl for 4 h at room temperature; the pellet was washed with sterile, deionized water and fragments were further extracted using 50 mM ammonium bicarbonate at 658C for 5 h. The HCl fraction was dialyzed against water (2000 MWCO Slide-A-Lyzer Cassettes; Pierce) for 4 days at 48C, then lyophilized to completion.…”

DNA and bone structure preservation in medieval human skeletons

“…Usually, only the lacunocanalicular network is observed in archaeological bones, such as in the immunohistochemistry images in the present study. Mineralized osteocytes have been A c c e p t e d M a n u s c r i p t previously described in fossilized bone dating to the Cretaceous and Jurassic periods [32,33] and 5 million years BP [31]. These cells have been shown to mineralize in vivo, as a form of in vivo death, and are a potential source of preserved DNA [31].…”

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

“…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).…”

“…Another critical factor in the preservation of more labile tissues in fossils is the sediment in which they are buried (Allison and Briggs, 1991;Schweitzer et al, 2007;Piñeiro et al, 2012). From site to site, sedimentary deposits will vary in texture, porosity, permeability, groundwater geochemistry, and microbial composition (Briggs, 2003;Maier et al, 2009).…”