原古蜥属（学名：Protorothyris）是种已灭绝原古蜥科，生存于二叠纪早期的美国德州、西维吉尼亚州，体型接近现代蜥蜴，约30公分长。菲尔德自然史博物馆有个原古蜥骨架模型。

在1937年，古生物学家Llewellyn Ivor Price将这些化石进行叙述、命名，模式种是Protorothyris archeri。正模标本（编号MCZ 1532）是一个保存状态良好的头颅骨，除此之外还有四个化石（编号MCZ 2147-2150）。这些标本都发现于德州的阿彻城组（Archer City Formation）地层，地质年代约2亿9900万到2亿9460万年前，相当于二叠纪早期的阿瑟尔期到乌拉尔期。

Protorothyris is an extinct genus of Early Permian protorothyridid known from Texas and West Virginia of the United States. It was first named by Llewellyn Ivor Price in 1937 and the type species is Protorothyris archeri. P. archeri is known from the holotype MCZ 1532, a three-dimensionally preserved skull and from the referred specimens, which come from four additional individuals, MCZ 2147-2150. All specimens were collected in the Cottonwood Creek site, from the Archer City Formation, Texas, dating to the Asselian stage of the Cisuralian epoch, about 299-294.6 million years ago. A second species, P. morani, was first named by Alfred Sherwood Romer in 1952 with its own generic name, Melanothyris. In 1973, J. Clark and Robert L. Carroll recombined P. morani as a Protorothyris species. It is known from the holotype CM 8617, a three-dimensionally preserved skull. It was collected in the Blacksville site, from the Washington Formation (Asselian stage) of West Virginia. Protorothyris was the size of a lizard, about 30 cm in length.