2015/11/23 by Kirstin S. Brink, Hillary C. Maddin, David C. Evans +1 · 21 citations
Earth and Planetary Sciences · Environmental Science · #Amphibian and Reptile Biology #Autapomorphy #Biology #Clade #Cladistics #Dentition #Evolution and Paleontology Studies #Geology #Holotype #Paleontology #Paleontology and Evolutionary Biology #Permian #Phylogenetic tree #Sister group #Snout #Structural basin #Taxon #Taxonomy (biology) #Zoology
paper · open access · doi:10.1139/cjes-2015-0100
published in Canadian Journal of Earth Sciences 52(12), 1109-1120 (NRC Research Press)
openalex publication_date 2015/11/23 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/25
The holotype and only known specimen of Bathygnathus borealis is a partial snout with maxillary dentition of a presumed sphenacodontid from the Lower Permian (Artinskian 283–290 Ma) redbeds of Prince Edward Island, Canada. Due to its incomplete nature, assessment of the taxon’s systematic position within a cladistic analysis had never been performed. However, recent recognition of the phylogenetic utility of tooth characters in sphenacodontids now allows for a modern phylogenetic evaluation of B. borealis. Results show that B. borealis is the sister taxon of Dimetrodon grandis, which is supported by dental characters: crowns with mesial and distal denticles and roots elongate, lacking plicidentine. An autapomorphy of B. borealis is the large facial exposure of the septomaxilla. As Bathygnathus has priority over Dimetrodon in the scientific literature, we suggest a reversal of precedence is required to preserve the familiar name Dimetrodon and to maintain universality, thus recognizing the new species Dimetrodon borealis.