THE IMPACT OF SEASONAL VARIATION ON PATTERNS OF REPTILIAN DECOMPOSITION

Historically, vertebrate actualistic studies on taphonomic processes have focused on mammalian decomposition, leaving other clades understudied. In general, patterns of decomposition in non-mammalian groups are assumed to follow similar patterns to the mammalian model, but a growing body of research is suggesting that anatomical differences among vertebrate clades can affect decomposition.

To observe reptilian decomposition patterns and assess the effects of seasonal variation, we set out two sets of thirty Argentine tegus (Salvator merianae) to decay naturally in a wooded clearing in Knoxville, TN. They were placed in a wood-framed, chicken-wire box to allow access by smaller invertebrates but not larger vertebrates. One set was emplaced in the summer (May 2023) and the other in the winter (February 2024). Observations were made daily during the early stages of decomposition to monitor body position, invertebrate activity, stage of decomposition, etc. Weather data was collected from the National Weather Service.

Our observations have mostly aligned with previous studies detailing seasonal variation of decay among mammals; however, some differences occurred related to skin retention and disarticulation order. Every individual in the summer run entered the dry stage of decomposition in under a month while some individuals in the winter run didn’t enter the dry stage until five months. Furthermore, insect communities differed between the runs as temperature fluctuations and colder conditions impacted their life cycle, leading to downstream effects on the pattern of disarticulation and the quality of skin retention. These findings suggest that broad patterns of reptilian decomposition vary in predictable ways based on seasonal differences at the time of death, but also that the observed processes can and do vary from the mammalian model.

Funding statement: This research was funded by the University of Tennessee Department of Earth, Environmental, and Planetary Sciences and the David B. Jones Foundation.