Synchrotron Reveals Early Triassic Odd Couple: Injured Amphibian and Aestivating Therapsid Share Burrow

Abstract

Fossorialism is a beneficial adaptation for brooding, predator avoidance and protection from extreme climate. The abundance of fossilised burrow casts from the Early Triassic of southern Africa is viewed as a behavioural response by many tetrapods to the harsh conditions following the Permo-Triassic mass-extinction event. However, scarcity of vertebrate remains associated with these burrows leaves many ecological questions unanswered. Synchrotron scanning of a lithified burrow cast from the Early Triassic of the Karoo unveiled a unique mixed-species association: an injured temnospondyl amphibian (Broomistega) that sheltered in a burrow occupied by an aestivating therapsid (Thrinaxodon). The discovery of this rare rhinesuchid represents the first occurrence in the fossil record of a temnospondyl in a burrow. The amphibian skeleton shows signs of a crushing trauma with partially healed fractures on several consecutive ribs. The presence of a relatively large intruder in what is interpreted to be a Thrinaxodon burrow implies that the therapsid tolerated the amphibian’s presence. Among possible explanations for such unlikely cohabitation, Thrinaxodon aestivation is most plausible, an interpretation supported by the numerous Thrinaxodon specimens fossilised in curled-up postures. Recent advances in synchrotron imaging have enabled visualization of the contents of burrow casts, thus providing a novel tool to elucidate not only anatomy but also ecology and biology of ancient tetrapods.

Reconstructing the Auditory Apparatus of Therapsids by Means of Neutron Tomography

“…However, there is a possibility to scan larger samples at some facilities such as the ESRF in Grenoble, which makes synchrotron X-rays also suitable for examinations of fossil synapsid skulls. Examples for examinations of therapsid fossils with synchrotron radiation are the investigation of the small anomodont Niassodon from the Late Permian of Mozambique (Castanhinha et al 2013) and the investigation of a burrow cast with skeletons of the cynodont Thrinaxodon liorhinus and the temnospondyl amphibian Broomistega putterilli (Fernandez et al 2013). …”

Aggregations and parental care in the Early Triassic basal cynodontsGalesaurus planicepsandThrinaxodon liorhinus

“…A single skeleton of Galesaurus was found together with two procolophonids and a millipede, which was interpreted as a case of interspecific shelter-sharing (Abdala, Cisneros & Smith, 2006). In another case, a micro-computed tomography scan of a burrow cast revealed a skeleton of Thrinaxodon preserved alongside an injured Broomistega (Fernandez et al, 2013). It was hypothesized that Thrinaxodon was aestivating when the injured temnospondyl entered the burrow (Fernandez et al, 2013).…”

Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming

“…These climatic changes would greatly alter the survivability and longevity of animals in general and poikilotherms in particular. Production of active 121 February 26, 2016|Volume 7|Issue 1| WJBC|www.wjgnet.com Ta). The ability to maintain a thermoneutral range is mostly due to an increase in heat dissipation.…”

“…These physiological and biochemical concerns appear to be the core elements of hypometabolism throughout the animal kingdom [117] . For example, the above phenomenon is observed in insects such as lady beetles (Coccinellidae) [118] and mosquitoes [119] , in Australian land snail Rhagada tesco rum [120] , in amphibians such as Broomistega putterilli [121] and California redlegged frog and in waterholding frog [122] , in African lungfish [123,124] , in mammals [125] such as Malagasy fattailed dwarf lemur [126] and East African Hedgehogs [127] . From the above discussion, it is expected that under high temperature in summer season, the aestivating animals due to adaptation especially metabolic depression (here it is an adaptation) and in nonaestivating animals due to long term adaptation to temperature [128] , rise in OS is not expected [6] .…”