George Gaylord Simpson
Published: 1957
Total Pages: 128
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"One. A large collection, mainly of isolated molars, from Águas do Araxá, Brazil, seems to represent a single population within a species identified as Haplomastodon waringi. The variation, described in some detail, is far greater than has hitherto usually been taken into consideration in the diagnosis of supposed species of mastodonts. 2. Mastodonts have been found at many localities scattered throughout Brazil. A few specimens are anomalous, but the great majority belong to, or are at least inseparable from, H. waringi on the basis of known characters. 3. Ecuadorian Haplomastodon is not at present specifically separable from H. waringi, and neither in Brazil nor in Ecuador is there good evidence of the presence of more than one species (or subgenus). 4. The only species and genera that now seem to be clearly distinct among South American mastodonts are Cuvieronius hyodon, Haplomastodon waringi, and Stegomastodon platensis. All these names have numerous synonyms. The species Stegomastodon superbus and the genus and species Notiomastodon ornatus are also tentatively listed as distinct, but are of doubtful status. 5. Haplomastodon is believed to be about as closely related to Cuvieronius as to Stegomastodon. 6. All the South American mastodonts seem to represent end terms of divergence within a single broad stock. Cuvieronius, Stegomastodon, and probably also Haplomastodon were already differentiated before they spread from North America to South America. The North American Rhynchotherium may belong to the same complex. All may ultimately have arisen from early Old World Anancinae, and all are tentatively referred to that subfamily"--P. 185.