REVISION OF THE TYPE MATERIAL AND NOMENCLATURE OFMASTODONSAURUS GIGANTEUS(JAEGER) (TEMNOSPONDYLI) FROM THE MIDDLE TRIASSIC OF GERMANY

Abstract

Abstract: The type material ofMastodonsaurusis revised and its complicated taxonomic history resolved. The genus was erected by Jaeger in 1828 without a species name, which was added subsequently by Holl (1829) who named the type speciesMastodonsaurus jaegeri.The large tooth on which Jaeger based hisMastodonsaurusis chosen herein as lectotype of the type species. A smaller second individual, represented by a piece of an occiput, was also named by Jaeger in 1828 asSalamandroides giganteusand, owing to the find of a complete skull, was recognized in 1833 by the same author as belonging to the same species as theMastodonsaurus. Therefore,Mastodonsaurus giganteus(Jaeger, 1828) is a senior subjective synonym of the type speciesM. jaegeriHoll, 1829. The precedence of the two generic names was chosen in 1834 by the first reviser, von Alberti, in favour ofSalamandroides, but all later authors, including von Alberti himself, followed Jaeger, who decided in 1837 to retain the nameMastodonsaurus. The established usage ofMastodonsaurusis preserved formally herein (nomen protectum). The namesBatrachosaurusFitzinger, 1837, andLabyrinthodonOwen, 1841 are unjustified replacement names ofMastodonsaurus. The namesM. jaegerivon Meyer, 1832,S. jaegerivon Alberti, 1834 andM. salamandroidesJaeger, 1837 are junior homonyms and synonyms ofM. jaegeriHoll, 1829, andM. giganteus(Jaeger, 1828), respectively. A recent attempt to replace the universally used Capitosauroidea Watson, 1919 by the unused and newly elevated Mastodonsauroidea Lydekker, 1885 is rejected. Two older synonyms of Mastodonsauridae Lydekker, 1885 (nomen protectum) are rejected as unavailable (Labyrinthodontidae vonMeyer, 1842) andnomen oblitum(Batrachosauridae Fitzinger, 1843), respectively. The holotype ofMastodonsaurus giganteusis reinstated and valid on the basis of three diagnostic features present: the tripartite posterior rim of the parasphenoid, a laterally pushed suture between the parasphenoid and basipterygoid, and a wide slit‐like eustachian tube opening.Mastodonsaurusis known from specimens representing a continuous growth series, now also encompassing the lectotype ofMastodonsaurus jaegeri, which until rather recently stood isolated from other specimens as the largest find by far.