Eozostrodon
Eozostrodon is an extinct morganucodont mammaliaform. It lived during the Rhaetian stage of the Late Triassic. "Eozostrodon" is known from disarticulated bones from Wales and South West England and estimated to have been less than in head-body length, slightly smaller than the similar-proportioned "Megazostrodon". "Eozostrodon" was described on the basis of two teeth discovered in a quarry near Frome in Somerset, England, each originally assigned to separate species "E. parvus" and "E. problematicus". The latter was synonymized in 1971. The identity of and status of "Eozostrodon" is controversial. Kühne considered "Eozostrodon" to be "one and the same  with Morganucodon" which he described, albeit after the published description of "Eozostrodon", claiming "...for a number of good reasons "Morganucodon" ought to be used, the name of "Eozostrodon" being used for sentimental reasons only or because of ignorance." Jenkins and Crompton in 1979 argued "Morganucodon" was a subjective synonym of "Eozostrodon", yet Clemens (1979) argued for the distinction. A more recent publication again distinguished the two, noting that "Eozostrodon" differs from "M. watsoni" in relative size and shape of premolar structures. Its teeth were typical for an early mammaliaform, being differentiated into premolars and molars with triangular cusps.