Taphonomic and Diagenetic Pathways to Protein Preservation, Part II: The Case of Brachylophosaurus canadensis Specimen MOR 2598
5
Citation
185
Reference
10
Related Paper
Citation Trend
Abstract:
Recent recoveries of peptide sequences from two Cretaceous dinosaur bones require paleontologists to rethink traditional notions about how fossilization occurs. As part of this shifting paradigm, several research groups have recently begun attempting to characterize biomolecular decay and stabilization pathways in diverse paleoenvironmental and diagenetic settings. To advance these efforts, we assessed the taphonomic and geochemical history of Brachylophosaurus canadensis specimen MOR 2598, the left femur of which was previously found to retain endogenous cells, tissues, and structural proteins. Combined stratigraphic and trace element data show that after brief fluvial transport, this articulated hind limb was buried in a sandy, likely-brackish, estuarine channel. During early diagenesis, percolating groundwaters stagnated within the bones, forming reducing internal microenvironments. Recent exposure and weathering also caused the surficial leaching of trace elements from the specimen. Despite these shifting redox regimes, proteins within the bones were able to survive through diagenesis, attesting to their remarkable resiliency over geologic time. Synthesizing our findings with other recent studies reveals that oxidizing conditions in the initial ~48 h postmortem likely promote molecular stabilization reactions and that the retention of early-diagenetic trace element signatures may be a useful proxy for molecular recovery potential.Keywords:
Taphonomy
Fossilization
Bioerosion
Trace element
Abstract Taphonomic experiments provide important insights into fossils that preserve the remains of decay‐prone soft tissues, tissues that are usually degraded and lost prior to fossilization. These fossils are among the most scientifically valuable evidence of ancient life on Earth, giving us a view into the past that is much less biased and incomplete than the picture provided by skeletal remains alone. Although the value of taphonomic experiments is beyond doubt, a lack of clarity regarding their purpose and limitations, and ambiguity in the use of terminology, are hampering progress. Here we distinguish between processes that promote information retention and those that promote information loss, in order to clarify the distinction between fossilization and preservation. Recognizing distinct processes of decay, mineralization and maturation, the sequence in which they act, and the potential for interactions, has important consequences for analysis of fossils, and for the design of taphonomic experiments. The purpose of well‐designed taphonomic experiments is generally to understand decay, maturation and preservation individually, thus limiting the number of variables involved. Much work remains to be done, but these methodologically reductionist foundations will allow researchers to build towards more complex taphonomic experiments and a more holistic understanding and analysis of the interactions between decay, maturation and preservation in the fossilization of non‐biomineralized remains. Our focus must remain on the key issue of understanding what exceptionally preserved fossils reveal about the history of biodiversity and evolution, rather than on debating the scope and value of an experimental approach.
Fossilization
Taphonomy
CLARITY
Geologic record
Cite
Citations (56)
Taphonomy
Fossilization
Cite
Citations (7)
Taphonomy
Fossilization
Cite
Citations (7)
Biominerals are recorders of evolution and palaeoenvironments. Predation is one of the most frequent modes leading to the concentration of small vertebrates in fossil assemblages. Consumption by predators produces damages on bones and teeth from prey species, and one of the greatest challenges to taphonomists is differentiating original biological and secondary, geologically altered attributes of fossils. Excellent morphological preservation is often used to assume that the structure and composition of fossils are not modified. Nevertheless, during predation and fossilization, both the physical structure and chemical composition of enamel, dentine and bone are altered, the degree and extent of which varies from site to site, depending on the nature of the burial environment. A relationship between the surficial alterations and the compositional changes which take place during fossilization has yet to be established. Herein, I present a review of old and recent taphonomic studies that collectively reveal the wide diversity of microstructural and chemical changes that typically take place during fossilization of vertebrate remains, including common taphonomic biases and the challenges inherent to reconstructing the history of vertebrate fossil assemblages.
Taphonomy
Fossilization
Bioerosion
Cite
Citations (4)
Fossilization
Taphonomy
Bioerosion
Cite
Citations (141)
Abstract Biomineralized tissues are chemically altered after death, and this diagenetic alteration can obscure original biological chemical features or provide new chemical information about the depositional environment. To use the chemistry of fossil biominerals to reconstruct biological, environmental or taphonomic information, a solid appreciation of biomineralization, mineral diagenesis and biomineral–water interaction is needed. Here, I summarize the key recent developments in the fields of biomineralization and post‐mortem trace element exchange that have significant implications for our understanding of the diagenetic behaviour of biominerals and the ways in which biomineral chemistry can be used in palaeontological and taphonomic research.
Taphonomy
Fossilization
Cite
Citations (69)
To gain better insights into taphonomic processes and the conditions generally associated with becoming part of the paleontologic record, students in my first-year seminar on mass extinctions, after procuring readily available materials at a local supermarket, buried and six weeks later exhumed a wide range of organisms that had recently expired. Based on their knowledge of common fossils studied in a previous exercise and on our field-based burial experiment, students formulated and tested hypotheses about the preservational potential of different organisms and gained experience with scientific methodology involving data collection, analysis, and synthesis. This experiment successfully mimicked the very early stages in the preservation process and enabled introductory students to make reasonable predictions that they could test about the kinds of organisms that are most likely to become preserved as fossils, the conditions that are conducive for entry into the geologic record, and the rarity of fossilization.
Fossilization
Taphonomy
Fossil Record
Geologic record
Cite
Citations (3)
Taphonomy
Cite
Citations (39)
In its original sense, taphonomy comprises all processes that lead to the transformation of dead tissue from the biosphere into the lithosphere. Quite recently, debates arose on a possibly broader redefinition of this term. In fact sciences other than paleontology have meanwhile adopted the term, in particular forensic scientists with a focus on the early stages of the disintegration of a corpse, and both physical anthropologists and archaeologists who are mainly concerned with the decomposition of skeletal finds from the Holocene. As a consequence, today the poorly defined term “decomposition” is frequently used more or less synonymously to “taphonomy.” By definition, the whole taphonomic process is subdivided into the four consecutive stages of necrology, biostratinomy, burial, and diagenesis. Fossilization is a rare event, because the normal fate of dead tissue in nature is complete disintegration and the recycling of matter. Very special burial conditions must prevail to turn a body or its parts into a “perfect fossil” where size and shape is preserved. This chapter presents an overview on the most important processes that are relevant for tissue preservation, decomposition, and fossilization.
Taphonomy
Fossilization
Bioerosion
Fossil Record
Cite
Citations (2)