Life image of Protorothyris archeri
- North America
The Protorothyrididae are a group of extinct reptiles from the Upper Carboniferous. The findings of these animals are mainly from Nova Scotia to northern Canada and were found in hollow trees shed. The most common types are Hylonomus lyelli and Paleothyris acadiana, both about 20 inches long.
Due to the characteristics of the dentition and the small body size of the Protorothyrididae were probably insect hunters. Very strongly developed was the skeleton of the chest and neck area. The scapula and coracoid, which had grown to a Scapulocoracoid, before which lay a thin collarbone and a Cleithrum. The latter is no longer present in modern reptiles.
The Protorothyrididae be assigned to the Anapsiden in traditional systematics because of their lack of cranial window. However, they are as primitive, skull windowless representatives of leading to the Diapsiden clade. This clade is referred to as cladistics Eureptilia.