Temnospondyl ontogeny and phylogeny, a window into terrestrial ecosystems during the Permian-Triassic mass extinction

Abstract

Temnospondyls are the most species-rich group of early amphibians, but specieslevel phylogenetic analyses of this large clade have so far only incompletely sampled the group. This study represents the largest and most comprehensive species-level phylogenetic study of Temnospondyli, sampling 99 taxa for 297 morphological characters from all seven continents through nearly 170 million years of their evolutionary history. Results of this analysis support the monophyly of several clades. Phylogenetic definitions are updated and three new clades names are proposed: Eutemnospondyli, Neostereospondyli, and Latipalata. Major splits within temnospondyl evolution are recovered at the base of Eutemnospondyli (Euskelia and Limnarchia) and Neostereospondyli (Capitosauria and Trematosauria). Archegosauriodea is recovered within Euskelia. Dendrerpeton is recovered as the immediate sister taxon of Dissorophoidea, not Eryopoidea as previously hypothesized. This arrangement suggests that for subclade-level analyses of dissorophoids, which bear on the 'Temnospondyl Hypothesis' for a putative origin of Lissamphibia within dissorophoids, the convention of rooting on Dendrerpeton and including eyropoids in the ingroup should be re-evaluated in light of the new temnospondyl topology. Study of the tempo and mode of evolution within temnospondyl amphibians has been limited in the past by the availability of a clade-wide, species-level phylogenetic analysis. The phylogenetic dataset generated by this study has allowed for investigation into rates of origination and extinction amongst this long-lived group at a scale not previously available for exploration. Extinction rate and origination rate, when calculated strictly from stratigraphic data, showed a high correlation with the number of sampled ACKNOWLEDGMENTS I am very grateful to my advisor, Chris Brochu, and my committee, Hallie Sims, Jonathan Adrain, Doug Houston, Jason Anderson, and the University of Iowa Vertebrate Paleontology Discussion Group for all that they have done to help me on this project. I also am grateful to Phil Heckel and Russ Ciochon for their guidance in the early stages of this project. I thank S.

The cranial morphology of the temnospondylAustralerpeton cosgriffi(Tetrapoda: Stereospondyli) from the Middle-Late Permian of Paraná Basin and the phylogenetic relationships of Rhinesuchidae

“…The sister‐group of the Rhinesuchinae is a clade comprising U. senekalensis and the Australerpetinae. Regarding U. senekalensis , Romer () created the family Uranocentrodontidae, but later studies placed this taxon simply within the Rhinesuchidae (Carroll, ; Schoch & Milner, ; McHugh, ). The synapomorphies supporting U. senekalensis as the sister‐taxon of Australerpetinae are the presence of a tympanic crest sensu Shishkin et al .…”

“…Bolt & Lombard (), Carroll (), Coates (), Damiani (), Holmes et al . (), Laurin & Reisz (), Lebedev & Coates (), McHugh (), Morales & Shishkin (), Pawley & Warren (), Piñeiro, Marsicano & Lorenzo (), Ruta & Coates (), Ruta & Bolt (), Schoch & Witzmann (), Schoch (, ), Schoch et al . (), Warren & Marsicano (), Witzmann & Schoch (), and Yates & Warren ().…”

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.…”

“…However, long bone histological examination allows a direct assessment of various aspects of tetrapod paleobiology, such as ontogeny, growth patterns, and lifestyle (Chinsamy‐Turan, ; Ricqlès, ; Chinsamy‐Turan, ; Padian and Lamm, ). Long bone and osteoderm histology has been examined in ecologically diverse temnospondyls from the Permian and Triassic (Damiani, ; Steyer et al, ; Mukherjee et al, ; Sanchez et al, ; Witzmann and Soler‐Gijón, ; McHugh, ; Konietzko‐Meier and Klein, ; Konietzko‐Meier and Sander, ; Konietzko‐Meier and Schmitt, ; Sanchez and Schoch, ; McHugh, ), but only one recent study included a humerus of Lydekkerina (McHugh, ). In the present study, we apply histological and microanatomical approaches to reassess previous hypotheses pertaining to the biology and ecology of Lydekkerina .…”

A new species ofMetoposaurusfrom the Late Triassic of Portugal and comments on the systematics and biogeography of metoposaurid temnospondyls

“…Such an analysis is outside of the scope of this paper, because it will first require careful specimen-level revision of the African and North American taxa, of the sort exemplified by Sulej's meticulous (2002Sulej's meticulous ( , 2007 work on the Polish material. Given the lack of specimen-level, alpha-taxonomic revisions of taxa such as Apachesaurus, Arganasaurus, Dutuitosaurus, and Koskinonodon, it is not surprising that large-scale analyses of temnospondyl phylogeny often represent Metoposauridae with one or a few exemplars (e.g., McHugh, 2012;Schoch, 2013). Rectifying this situation should be a primary focus of future work on metoposaurids.…”