Incertae sedis
Jaekel (1910) described the taxon on the basis of a single specimen he found in the collections of the University of Göttingen, with a label that identified it as a temnospondyl from the Lower Buntsandstein (Early Triassic) of Saxony-Anhalt. The holotype, unnumbered GZG partial skull with the anterior tip missing, was destroyed during World War II. According to Stocker and Butler (2013), based on the photograph in the original description, the holotype skull was undoubtedly phytosaurian, making it putatively stratigraphically lowest phytosaur known. Jaekel (1910) found a potential match of the sediment in which the skull was preserved to the Wipperbrücke, Parforcehaus locality, a horizon at the very base of the Middle Buntsandstein near Bernburg. This would make the specimen early Olenekian (Smithian) in age. However, because the holotype was destroyed with no surviving casts, and its provenance cannot be confirmed without new specimens, it have been largely ignored by recent authors, or assumed that its reported stratigraphic occurrence was incorrect. Various authors referred "M. fraasi" to as "Paleorhinus fraasi" or "Parasuchus fraasi", while a more recent review of the Phytosauria, by Stocker and Butler (2013), refrained from doing so, assigning it to Phytosauria "Incertae sedis".