Reassessment of historic ‘microsaurs’ from Joggins, Nova Scotia, reveals hidden diversity in the earliest amniote ecosystem

  title={Reassessment of historic ‘microsaurs’ from Joggins, Nova Scotia, reveals hidden diversity in the earliest amniote ecosystem},
  author={Arjan Mann and Bryan M. Gee and Jason D. Pardo and David Marjanovi{\'c} and Gabrielle Ruth Adams and Ami S. Calthorpe and Hillary C. Maddin and Jason S. Anderson},
  journal={Papers in Palaeontology},
‘Microsaurs’ are traditionally considered to be lepospondyl non‐amniotes, but recent analyses have recovered a subset of ‘microsaurs’, the fossorially adapted Recumbirostra, within Amniota. This novel conclusion highlights the need for additional work to evaluate these competing hypotheses with the aim of refining the phylogenetic position of ‘microsaurs’. Of particular importance in this regard is the placement of potential close relatives of recumbirostrans to determine whether they support… 
Cranial anatomy and systematics of Dendrerpeton cf. helogenes (Tetrapoda, Temnospondyli) from the Pennsylvanian of Joggins, revisited through micro‐CT scanning
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Joermungandr bolti, an exceptionally preserved ‘microsaur’ from the Mazon Creek Lagerstätte reveals patterns of integumentary evolution in Recumbirostra
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The First Age of Reptiles? Comparing Reptile and Synapsid Diversity, and the Influence of Lagerstätten, During the Carboniferous and Early Permian
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  • Environmental Science, Biology
    Frontiers in Ecology and Evolution
  • 2021
An examination of local species richness (alpha diversity) of synapsids and reptiles during the Pennsylvanian and Cisuralian at different spatial scales shows that these taxonomic revisions have substantial impacts on relative diversity patterns of synapid and reptiles.
A Mississippian (early Carboniferous) tetrapod showing early diversification of the hindlimbs
A new East Kirkton tetrapod with an unusual hindlimb morphology reminiscent of that of several stem- and primitive crown amniotes is named and described, with a unique ilium with two slender and elongate processes and a 5-digit pes with a long, stout metatarsal IV and a greatly elongate digit IV.
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The well-defined isometry, and particularly, the high interrelation between metatarsals and phalanges permit us to suggest that the mesosaur hind limb is subject to notable modularity, which would position them as more basal amniotes than previously thought.
The Making of Calibration Sausage Exemplified by Recalibrating the Transcriptomic Timetree of Jawed Vertebrates
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Phylogeny, function and ecology in the deep evolutionary history of the mammalian forelimb
This work quantitatively compared the forelimb shapes of the multiple fossil synapsid radiations to a broad sample of extant Mammalia representing a variety of divergent locomotor ecologies and indicates that eachsynapsid radiation explored different areas of morphospace and arrived at functional solutions that reflected their distinctive ancestral morphologies.
Carboniferous tetrapod biostratigraphy, biochronology and evolutionary events
  • S. Lucas
  • Geography, Environmental Science
    Special Publications
  • 2021
Abstract Tetrapod (amphibian and amniote) fossils of Carboniferous age are known almost exclusively from the southern part of a palaeoequatorial Euramerican province. The stratigraphic distribution
Can We Reliably Calibrate Deep Nodes in the Tetrapod Tree? Case Studies in Deep Tetrapod Divergences
It is found that node priors for amphibians and tetrapods show high phylogenetic lability and different phylogenetic treatments identifying disparate taxa as the earliest representatives of these crown groups, and it is suggested that sampling outside of classic European and North American sections may dramatically change the timelines of tetrapod evolution.


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New material of the ‘microsaur’ Llistrofus from the cave deposits of Richards Spur, Oklahoma and the paleoecology of the Hapsidopareiidae
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A Re-Description of ‘Mycterosaurus’ smithae, an Early Permian Eothyridid, and Its Impact on the Phylogeny of Pelycosaurian-Grade Synapsids
An expanded version of a recently published phylogenetic analysis of pelycosaurian-grade synapsids positions Vaughnictis as the sister taxon of Eothyris within the clade Eothirididae, and confirms the recently-disputed position of caseasaurs as the most basal synapsid.
First arboreal 'pelycosaurs' (Synapsida: Varanopidae) from the early Permian Chemnitz Fossil Lagerstätte, SE Germany, with a review of varanopid phylogeny
Systematic results suggest a varanodontine position for Mycterosaurus, the monophyly of South African varanopids including Anningia and the distinction of a skeletal aggregation previously assigned to Heleosaurus, now renamed as Microvaranops parentis gen. et sp.
Cranial Morphology of Recumbirostrans (Lepospondyli) from the Permian of Kansas and Nebraska, and Early Morphological Evolution Inferred by Micro-Computed Tomography
ABSTRACT ‘Microsaurs’ (Lepospondyli) were a group of tetrapods whose fossil record spanned the Mississippian—Early Permian, and have sometimes been implicated in the origins of lissamphibians
The Paleozoic Microsaurs as Close Relatives of Reptiles, Again
Earlier suggestions of relationship of the late Paleozoic microsaurs, usually classified as lepospondylous amphibians, to captorhin- omorph cotylosaurian reptiles were opposed on grounds of
Diabloroter bolti, a short-bodied recumbirostran ‘microsaur’ from the Francis Creek Shale, Mazon Creek, Illinois
Diabloroter is determined to be the earliest known member of Brachytelechidae and thus establishing a Carboniferous origin of the family, and an updated diagnosis for Brachystelechidae is provided.
Cranial Morphology of the Carboniferous-Permian Tetrapod Brachydectes newberryi (Lepospondyli, Lysorophia): New Data from µCT
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