Solenodonsaurus is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of Reptiliomorpha

Reptiliomorpha

Reptiliomorpha refers to an order or subclass of reptile-like amphibians, which gave rise to the amniotes in the Carboniferous. Under phylogenetic nomenclature, the Reptiliomorpha includes their amniote descendants though, even in phylogenetic nomenclature, the name is mostly used when referring to...

, which lived about 320-305 million years ago. Classification is uncertain, but it was possibly an early reptile

Reptile

Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

 or an amphibian close to the diadectomorphs. Its remains were found in the Czech Republic

Czech Republic

The Czech Republic is a landlocked country in Central Europe. The country is bordered by Poland to the northeast, Slovakia to the east, Austria to the south, and Germany to the west and northwest....

. Its name means, single-tooth lizard.

The Solenodonsaurus show a curious mix of characters making it difficult to place phyllogentically. The teeth lack labyrinthodont folding of the enamle, and it skull is without the otic notch

Otic notch

Otic notches are invagination in the posterior margin of the skull roof, one behind each orbit. Such notches are found in labyrinthodonts and some of their immediate ancestors, but not their reptilian descendants...

 seen in other reptiliomorph amphibians. Yet general build ties it in with the Diadectomorpha

Diadectomorpha

Diadectomorpha are a clade of large reptile-like amphibians that lived in Euramerica during the Carboniferous and Early Permian periods, and are very close to the ancestry of the Amniota. They include both large carnivorous and even larger herbivorous forms, some semi-aquatic and others fully...

.