Illustration of Monitor lizard (Lacerta monitor) now known as the Nile monitor (Varanus niloticus) from J. Frid Gmelin and Carl Linnaeus (posthumous). 'A Genuine and Universal System of Natural History comprising the three Kingdoms of Animals; Vegetables and Minerals. Arranged under their respective Classes; Orders; Genera and Species'. Published in London; 1794 1810. Linnaeus originally put the reptiles and amphibians together in one group and it was not until the 19th century that they were recognised a being very distinct groups.