Open AccessRe-evaluation of the historic Canadian fossil Bathygnathus borealis from the Early Permian of Prince Edward Island
Author(s) -
Kirstin S. Brink,
Hillary C. Maddin,
David C. Evans,
Robert R. Reisz
Publication year - 2015
Publication title -
canadian journal of earth sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.525
H-Index - 75
eISSN - 1480-3313
pISSN - 0008-4077
DOI - 10.1139/cjes-2015-0100
Subject(s) - autapomorphy , paleontology , cladistics , taxon , holotype , permian , sister group , dentition , phylogenetic tree , snout , geology , clade , zoology , biology , taxonomy (biology) , structural basin , biochemistry , gene
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.