Patterns of aquatic decay and disarticulation in juvenile Indo-Pacific crocodiles (Crocodylus porosus), and implications for the taphonomic interpretation of fossil crocodyliform material

Syme, Caitlin E. and Salisbury, Steven W. (2014) Patterns of aquatic decay and disarticulation in juvenile Indo-Pacific crocodiles (Crocodylus porosus), and implications for the taphonomic interpretation of fossil crocodyliform material. Palaeogeography, Palaeoclimatology, Palaeoecology, 412 108-123. doi:10.1016/j.palaeo.2014.07.031


Author Syme, Caitlin E.
Salisbury, Steven W.
Title Patterns of aquatic decay and disarticulation in juvenile Indo-Pacific crocodiles (Crocodylus porosus), and implications for the taphonomic interpretation of fossil crocodyliform material
Journal name Palaeogeography, Palaeoclimatology, Palaeoecology   Check publisher's open access policy
ISSN 0031-0182
1872-616X
Publication date 2014-10-05
Year available 2014
Sub-type Article (original research)
DOI 10.1016/j.palaeo.2014.07.031
Open Access Status
Volume 412
Start page 108
End page 123
Total pages 16
Place of publication Amsterdam, The Netherlands
Publisher Elsevier
Collection year 2015
Language eng
Formatted abstract
High levels of skeletal articulation and completeness in fossil crocodyliforms are commonly attributed to rapid burial, with decreasing articulation and completeness thought to result from prolonged decay of soft tissue and the loss of skeletal connectivity during ‘bloat and float’. These interpretations are based largely on patterns of decay in modern mammalian and avian dinosaur carcasses. To address this issue, we assessed the decay of buried and unburied juvenile Crocodylus porosus carcasses in a controlled freshwater setting. The carcasses progressed through typical vertebrate decay stages (fresh, bloated, active decay, and advanced decay), reaching the final skeletal stage on average 55 days after death. Unburied carcasses commenced floating five days post-mortem during the bloated stage, and one buried carcass only commenced floating 12 days post-mortem. While floating, skeletal elements remained articulated within the still coherent dermis, except for thoracic ribs, ischia and pubic bones. The majority of disarticulation occurred at the sediment–water interface after the carcasses sank during the advanced decay stage, ~ 36 days post-mortem. Based on these results we conclude that fossil crocodyliform specimens displaying high levels of articulation are not the result of prolonged subaerial and subaqueous decay in a low-energy, aqueous environment. Using extant juvenile C. porosus as a proxy for fossil crocodyliforms, rapid burial in an aquatic setting would have to occur prior to the carcass floating, and would also have to continually negate the positive buoyancy associated with bloating. Rapid burial does not have to be the only avenue to preservation of articulation, as other mechanisms such as physical barriers and internal physiological chemistry could prevent carcasses from floating and subsequently disarticulating upon sinking. The inference that a large proportion of skeletal elements could drift from floating carcasses in a low energy setting with minimal scavenging, thereby causing a loss of completeness, seems unlikely.
Keyword Actuopalaeontology
Crocodyliform
Decay experiment
Disarticulation
Taphonomy
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Biological Sciences Publications
 
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