Salamander-like development in a seymouriamorph revealed by palaeohistology

Abstract

The amniotes generally lay eggs on land and are thereby differentiated from lissamphibians (salamanders, frogs and caecilians) by their developmental pattern. Although a number of 330–300-Myr old fossils are regarded as early tetrapods placed close to amniotes on the basis of anatomical data, we still do not know whether their developmental pattern was more similar to those of lissamphibians or amniotes. Here we report palaeohistological and skeletochronological evidence supporting a salamander-like development in the seymouriamorph Discosauriscus . Its long-bone growth pattern, slow diaphyseal growth rate and delayed sexual maturity (at more than 10 years old) are more comparable with growth features of extant salamanders rather than extant amniotes, even though they are mostly hypothesized to be phylogenetically closer to living amniotes than salamanders.

Bone Microstructure of the Stereospondyl Lydekkerina Huxleyi Reveals Adaptive Strategies to the Harsh Post Permian‐Extinction Environment

“…Several paleohistological studies have been conducted on Permo‐Triassic temnospondyls (Enlow and Brown, ; Ricqlès, ; Damiani, ; Laurin et al, ; Ricqlès et al, ; Steyer et al, ; Sanchez et al, ; Ray et al, ; Mukherjee et al, ; Sanchez et al, ; Witzmann and Soler Gijón, ; McHugh, ; Konietzko‐Meier and Klein, ; Konietzko‐Meier et al, ; Konietzko‐Meier and Sander, ; Konietzko‐Meier and Schmitt, ; Sanchez and Schoch, ; McHugh, ), but few included Early Triassic amphibian material (Damiani, , Ray et al, ; Mukherjee et al, ; McHugh, ) and even fewer have focused on Karoo Basin taxa (McHugh, ). Besides being the first comprehensive work on Lydekkerina 's bone microstructure, the current study contributes to the better understanding of the paleobiology of Early Triassic amphibians, and sheds new light on the convergent adaptive strategies of the continental tetrapod fauna to the harsh post Permian‐extinction environment of the Karoo Basin.…”

3D Microstructural Architecture of Muscle Attachments in Extant and Fossil Vertebrates Revealed by Synchrotron Microtomography

“…Extrinsic muscle attachment fibres are frequently seen in thin sections of fossil bones, e.g. [3], [5], [27], [33], [34], indicating that there is an enormous pool of fossil data that can potentially be retrieved by this technique. Because PPC-SRµCT generates directly comparable data sets from fossil and recent specimens, it provides a unique platform for making in-depth comparisons of muscle attachment architectures across vertebrate phylogeny and deep time.…”

Skeletochronology and isotopic analysis of a captive individual ofAlligator mississippiensisDaudin, 1802

“…Skeletochronology, the estimation of individual age based on bone histological data, has been well established to determine the ontogenetic age of Recent and fossil vertebrates (e.g., Ricql s 1968Ricql s , 1976aRicql s , 1976bZug et al 1986;Castanet et al 1988Castanet et al , 1993Castanet & Smirina 1990;Castanet 1994;Horner et al 1999Horner et al , 2000Steyer et al 2004;Chinsamy 1990Chinsamy , 1993Chinsamy-Turan 2005;Erickson & Tumanova 2000;Erickson et al 2004;Erickson 2005;Klein & Sander 2007;Sanchez et al 2008). However, these techniques are sometimes difficult to use because of the influence of bone remodeling and bone plasticity, and the sometimes irregular appearance of growth marks (Klein & Sander 2008).…”