Temnospondyli was named by German palaeontologist Karl Alfred von Zittel in his second edition of Handbuch der Palaeontologie , published in 1888 . Temnospondyl remains were known since the early part of the 19th century , however . The earliest described temnospondyl was Mastodonsaurus , named by Georg Friedrich Jaeger in 1828 . Jaeger named Mastodonsaurus from a single tooth , and considered it a reptile . Mastodonsaurus means " breast tooth lizard " after the nipple @-@ like shape of the tip of the tooth .