Asaphestera (Carboniferous Joggins tetrapod) not a synapsid (free pdf)
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Ben Creisler
Oct 31, 2025, 11:13:14 AM (6 days ago) Oct 31
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Ben Creisler
A new paper:
Robert R. Reisz & Sean P. Modesto (2025)
Re-evaluation of the Carboniferous tetrapod Asaphestera platyris with comments on the amniote fauna of the Joggins Formation, Canada
Papers in Palaeontology 11(6): e70044
doi: https://doi.org/10.1002/spp2.70044
https://onlinelibrary.wiley.com/doi/10.1002/spp2.70044
Free pdf:
https://onlinelibrary.wiley.com/doi/epdf/10.1002/spp2.70044
‘Microsaurs’ are problematic late Palaeozoic tetrapods that have been grouped with reptiles on the one hand, or regarded as close relatives of amniotes on the other. Early phylogenetic analyses that included broadly sampled tetrapod taxa placed ‘microsaurs’ as close relatives of amniotes. Several recent phylogenetic analyses have, by contrast, recovered ‘microsaurs’ as reptiles (i.e. within Amniota) and this has prompted some researchers to describe ‘microsaur’ taxa that have never been included in a phylogenetic analysis as amniotes. Prominent among these is Asaphestera platyris from the Joggins Formation, upper Carboniferous of Nova Scotia, Canada. A recent systematic review restricted this species to its holotype, argued that it is a synapsid, and transferred referred specimens to a new genus and species of ‘microsaur’. We re-examined the holotype of Asaphestera platyris and have concluded that, whereas it is not a synapsid, there are no compelling diagnostic features, and so regard Asaphestera platyris to be a nomen dubium. This systematic revision removes an alleged synapsid from the Joggins fauna and, combined with our recent conclusions elsewhere that there is no support for the hypothesis that recumbirostran ‘microsaurs’ are amniotes, we affirm previous interpretations that view Hylonomus lyelli and Protoclepsydrops haplous as the only amniote elements in the Joggins Formation.
Free pdf:
Robert R. Reisz & Sean P. Modesto (2025)
Re-evaluation of the Carboniferous tetrapod Asaphestera platyris with comments on the amniote fauna of the Joggins Formation, Canada
Papers in Palaeontology 11(6): e70044
doi: https://doi.org/10.1002/spp2.70044
https://onlinelibrary.wiley.com/doi/10.1002/spp2.70044
Free pdf:
https://onlinelibrary.wiley.com/doi/epdf/10.1002/spp2.70044
‘Microsaurs’ are problematic late Palaeozoic tetrapods that have been grouped with reptiles on the one hand, or regarded as close relatives of amniotes on the other. Early phylogenetic analyses that included broadly sampled tetrapod taxa placed ‘microsaurs’ as close relatives of amniotes. Several recent phylogenetic analyses have, by contrast, recovered ‘microsaurs’ as reptiles (i.e. within Amniota) and this has prompted some researchers to describe ‘microsaur’ taxa that have never been included in a phylogenetic analysis as amniotes. Prominent among these is Asaphestera platyris from the Joggins Formation, upper Carboniferous of Nova Scotia, Canada. A recent systematic review restricted this species to its holotype, argued that it is a synapsid, and transferred referred specimens to a new genus and species of ‘microsaur’. We re-examined the holotype of Asaphestera platyris and have concluded that, whereas it is not a synapsid, there are no compelling diagnostic features, and so regard Asaphestera platyris to be a nomen dubium. This systematic revision removes an alleged synapsid from the Joggins fauna and, combined with our recent conclusions elsewhere that there is no support for the hypothesis that recumbirostran ‘microsaurs’ are amniotes, we affirm previous interpretations that view Hylonomus lyelli and Protoclepsydrops haplous as the only amniote elements in the Joggins Formation.
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