mammal-like reptile

mammal-like reptile (plural mammal-like reptiles)

1. (paleontology, dated) Any basal member of the Synapsida, related to the mammals but superficially resembling reptiles.
   • 1966 — Alfred S. Romer, Vertebrate Paleontology, 3rd ed.; ch 14, p 173

     The mammal-like reptiles, constituting the subclass Synapsida, were among the earliest to appear of known reptilian groups and had passed the peak of their career before the first dinosaur appeared on the earth.

   • 1997 — Michael J. Benton, Vertebrate Paleontology, 2nd ed.; ch 5, p 109

     Synapsida: amniotes with one lower temporal fenestra, surrounded by the postorbital, jugal and squamosal. Includes the extinct mammal-like reptiles and the mammals.

This term has fallen out of favor among paleontologists, who now classify the mammals within the Synapsida. The term “basal synapsids” is preferred by cladists.