These are the most highly developed members of the typical Labyrinthodonta, characterised by their much-folded teeth, and by their solid, bi-concave vertebrae. Loxomma occurs in the Upper Carboniferous of England and in the Lower Red of Bohemia: Trematosaurus, Capitosaurus, and Metopias from the New Red or Lower Trias to the Keuper of Germany. Mastodonsaurus from the Trias of England and Germany is the most gigantic Amphibian known, with a skull of nearly 1 yard in length.
Labyrinthodon from the Keuper of Warwickshire is one of the latest members of the group. Labyrinthodont creatures have also been described from the Trias of South Africa, e.g. Rhytidosteus; those from North America are insufficiently preserved.
Many of these and allied genera have left their footprints in slabs of Sandstone, both Lower and New Red, in Europe, Africa, and America. But although their spoors are common enough, only a few can with certainty be referred to Stegocephali, e.g. Saurichnites salamandroides of the Lower Red of Germany. The spoors of Chirotherium, common in the New Red of Germany and England, for instance in Cheshire, belong to unknown owners; both the large hind feet (which measure nearly half a foot in length) and the much smaller fore feet, had five digits, the first of which stood off like a thumb. Five-fingered Stegocephali are unknown.
There is an almost complete absence of fossil Amphibia from the Upper Trias to the Oligocene. The Stegocephali as such seem to have died out with the Trias. The recent Amphibia, of course, must have had ancestors in the Mesozoic age. There is one little skeleton, from the Wealden of Belgium, which belonged to a newt-like creature, called Hylaeobatrachus croyi. Scarce fragments, described as Megalotriton, are known from the Oligocene of France, and Triton itself seems to be indicated by remnants in the Lower Miocene of France and Germany. But fairly complete specimens of large creatures, much resembling Cryptobranchus, have been found in the Upper Miocene of Oeningen, Canton Solothurn, Switzerland. The first known specimen, now at Haarlem, indicating a total length of 3 feet or more, was described and figured in the year 1726 by Scheuchzer, in a learned dissertation entitled "Homo diluvii testis."
Betrübtes Beingerüst von einem alten Sünder
Erweiche Herz und Sinn der neuen Bosheitskinder.
Which may be rendered as follows:–
Oh, sad remains of bone, frame of poor Man of sin
Soften the heart and mind of sinful recent kin.
This was the motto attached to the illustration, and it remained a warning to mankind until Cuvier declared the skeleton to be that of some large newt. Tschudi named it Andrias scheuchzeri, but it is scarcely generically distinct from Cryptobranchus, being almost intermediate between C. alleghaniensis and C. japonicus, see p. [97].