The oldest specialized tetrapod herbivore: A new eupelycosaur from the Permian of New Mexico, USA
- Environmental Science
Gordodon kraineri is a new genus and species of edaphosaurid eupelycosaur known from an associated skull, lower jaw and incomplete postcranium found in the early Permian Bursum Formation of Otero…
New information on the cranial and postcranial anatomy of the early synapsid Ianthodon schultzei (Sphenacomorpha: Sphenacodontia), and its evolutionary significance
- Biology, Geography
The Garnett locality appears to preserve an assemblage of synapsids that are close to the base of the large clade that includes Edaphosauridae and Sphenacodontia, suggesting that an initial diversification of this clade occurred well within the Carboniferous Period.
The Origin and Early Evolution of Sauria: Reassessing the Permian Saurian Fossil Record and the Timing of the Crocodile-Lizard Divergence
- Geography, Environmental SciencePloS one
A revision suggests a minimum fossil calibration date for the crocodile-lizard split of 254.7 Ma, and early archosauromorph growth strategies appear to be more diverse than previously suggested based on new data on the osteohistology of Aenigmastropheus.
New Postcranial Material of the Early Caseid Casea broilii Williston, 1910 (Synapsida: Caseidae) with a Review of the Evolution of the Sacrum in Paleozoic Non-Mammalian Synapsids
- BiologyPloS one
It is argued that this repeated acquisition of a three-vertebra sacrum in early synapsids was related to more efficient terrestrial locomotion than to increased weight bearing, suggesting that it was not an adaptation to heavy weight bearing.
Interrelationships of basal synapsids: cranial and postcranial morphological partitions suggest different topologies
A new phylogenetic dataset comprising 45 taxa (plus four outgroups and four therapsids) and 239 characters reveals considerable uncertainty in the relationships of higher clades of basal synapsids, and suggests well-supported phylogenetic placements for several taxa of historically uncertain affinities.
Comparative osteohistology of hyperelongate neural spines in the Edaphosauridae (Amniota: Synapsida)
Histological properties of hyperelongate neural spines in Lupeosaurus and other edaphosaurids do not meet previously established requirements of the thermoregulatory hypothesis, either calling into question the sail’s thermoreGulatory function in this group or indicating a reconsideration of those putative thermoregian adaptations and the purported soft‐tissue correlates of the sail.
On the Affinities of Tetraceratops insignis, an Early Permian Synapsid
This study examines the arguments proposed to refute therapsid affinities, and concludes that Tetraceratops indeed is the sister-group of all other known therappingids.
Morphology and Evolutionary Significance of the Atlas-Axis Complex in Varanopid Synapsids
The morphology exhibited by the transverse processes is interpreted as derived in varanodontines, whereas the morphology of the axial spine is derived in mycterosaurines, consistent with the hypothesis that at least two varanopid taxa are present in South Africa.
Evolutionary trends and the origin of the mammalian lower jaw
- Biology, GeographyPaleobiology
Results suggest that body size decreases cannot fully explain the reduction of the postdentary bones, and indicate that mandibular evolution was primarily conservative, with only anomodont therapsids evolving substantial morphological novelty.
A new species of Dimetrodon (Synapsida: Sphenacodontidae) from the Lower Permian of Germany records first occurrence of genus outside of North America
- Environmental Science, Biology
This first record of the sphenacodontid synapsid Dimetrodon outside of North America provides not only additional biological evidence of a continuous Euramerican landmass during the Early Permian, but also the absence of any major physical or biological barrier to faunal interchange of terrestrial vertebrates.