The Binns Gomphothere


The Binns gomphothere during excavation


The Vertebrate Museum of the Biology Department of New Mexico State University is the proud recipient of a donation of literally giant proportions: the eight-foot fossil skull of an elephant-like animal known as a gomphothere that was discovered in Mesquite just about ten miles south of campus.  A small piece of tusk exposed far up on a hillside at a local private sand and gravel quarry caught the attention of the keen eyes of Orlando Morales.  He and others from the quarry traced the tusk into the sediments, unearthing a massive intact skull of an extinct gomphothere of either the genus Cuvieronius or Rhynchotherium.  The two can be reliably distinguished from one another only by the presence or absence of additional tusks on the lower jaw, which unfortunately was not preserved with the skull.  Cuvieronius is reported to have occurred in the ancient Rio Grande valley while Rhynchotherium is known from as nearby as the ancient Gila River valley in Arizona.


Donor and NMSU alumnus Eddie Binns


The owner of the quarry, Eddie Binns, himself an NMSU alumnus, generously donated the specimen to NMSU in the interest of keeping it local.  It is not uncommon to find gomphothere fossils in the Las Cruces area, but not in this condition.  Moreover, those from state and federal lands are usually spirited away to repositories in Albuquerque or El Paso.


Eddie Binns spared no expense in assisting with the excavation.  The fossil is under the tarpaulin


Gomphotheres are mastodonts, meaning they have mastodon-like molars.  Like true mastodons they are distinct from elephants in the shape of their low-crowned molars, which are adapted for consuming a mixed diet of grasses, leaves, and fruits.  Gomphotheres are related to but more primitive than mastodons.  They form a distinct family with a 25 million year fossil record from around the world.  Cuvieronius resembled a modern elephant with somewhat stubby legs, straight but spirally twisted tusks, and stood about eight or nine feet tall.  Rhynchotherium was all but indistinguishable from Cuvieronius except for its relatively diminutive lower tusks.   Many other gomphotheres however had grotesquely huge shovel-shaped tusks erupting from the lower jaw and would be instantly recognizable as distinct from elephants.


A shovel-tusked gomphothere from China - the humeri are attached backwards - how embarrassing!  (courtesy of


Two or three gomphotheres (Cuvieronius and/or Rhynchotherium, and Stegomastodon), a mastodon, and one or more species of mammoths once lived in the ancient Rio Grande valley.  They are a reminder that our environment and the flora and fauna it supports are constantly changing.  Imagine giant camels, ground sloths, tapirs, and giant armadillos in prehistoric Las Cruces!  The Binns gomphothere is approximately one to two million years old, dating to the Pleistocene epoch, after which time it is widely believed to have gone extinct in North America.  However, two juvenile Cuvieronius fossils are reported to have been butchered by Paleo-Indians in Sonora, Mexico, and Cuvieronius survived in large numbers much later in South America where its flesh and hide also were utilized by Paleo-Indians.  


Artist's reconstruction of Cuvieronius (courtesy of


Some paleontologists claim that the two of the fossil gomphotheres said to coexist in the ancient Rio Grande valley are found in very different environments in South America.  Cuvieronius is found in great numbers in the cold Andes mountains of western South America while Stegomastodon is found in the warm lowlands of eastern Argentina and Brazil.  This lends credence to the notion that the South American species of Cuvieronius (C. hyodon or tarijensis) was not the same as ours (C. tropicus).  However, other experts disagree; they say that there is but one species of Cuvieronius (C. hyodon) and the South American version of Stegomastodon in truth is misidentified Haplomastodon.  All this taxonomic confusion stems largely from both the great deal of individual variation among specimens and the incomplete preservation of most specimens.


NMSU student and Vertebrate Museum volunteer Drew Gentry treating the Binns gomphothere with preservative prior to its removal


Fragments of bone and teeth of Pleistocene megafauna, including those of gomphotheres, are not uncommonly preserved in deposits of the Rio Grande valley floor and well as in local caves.  So the greatest significance of the Binns gomphothere is not its occurrence, but its unusually complete preservation and the fact that it will be permanently available for public viewing on the NMSU main campus, beneath the mounted whale skeleton  in the south atrium of Foster Hall.  The complete preservation of this skull may also help ultimately to clarify the differences that distinguish species of gomphotheres. 


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