Weekly Wonders: Rhynchotherium

12 09 2009

Good tidings and well-wishes!

My “real-life” correspondents and regular readers are doubtlessly unaware of my fascination with proboscideans, particularly those which, to date, have yet to appear in any “Ice Age” films. The latter half of this statement draws its origins from my general outlook on paleontology which I hope has also been reflected in my blog: that delightfully bizarre and relatively obscure animals deserve just as much attention from scientists and the media as their more familiar counterparts. Don’t get me wrong: mammoths are truly captivating beasts and I quite like examining dental specimens from M. columbi and (occasionally) M.  primigenius here at the MCC museum. But most people simply don’t realize that the order has seen far more players in its evolution, including some really peculiar creatures which must have been amazing to behold in their day.  Most of these oddballs hail from one of the more well-known families of proboscids, the Gomphotheriidae, which is by a wide margin the largest.

Bjorn Kurten and Elaine Anderson appear to concur with this conclusion in “Pleistocene Mammals of North America” wherein they write:

“Of the…proboscidean [families], the Gomphotheriidae- the pig-toothed beasts- show the greatest diversity and include[s] such specialized groups as the shovel-toothed amebelodonts, the beak-tusked rhynchotheres, and the short-jawed anacines (whose cranial specializations parallel those of the true elephants).  The main lineage, the bunodont gompotheres…can be traced to Phiomia (from the Oligocene of North Africa) to Gomphotherium (a widespread Miocene genus), Tetralophodon (from the Old World and North America), and Stegomastodon (from the late Tertiary and early Pleistocene of North and South America)…Although many diverse lines of Gomphotheres developed, the family has remarkably uniform dentition. Compared to the simple molars of the mastodonts, gomphothere molars are complex, with additional rounded cusps and accessory conules that wear to a complicated trefoil pattern. Tusks were usually present in both jaws. Gomphotheres had a longer body and head and shorter limbs than the true elephants.”

Though this post could easily evolve into a love letter to the family and, by extension, the order, I’m restraining myself to highlighting one specific genus in accordance with ‘Weekly Wonders’ tradition: Rhynchotherium sp.

A Rhynchotherium herd as drawn by Olduvai George.

A Rhynchotherium herd as drawn by "Olduvai George".

In “The Proboscidea: Evolution And Paleoecology Of Elephants And Their Relatives” (which is an amazing resource for anyone even remotely interested in these animals), W. David Lambert compares Rhynchotherium with the more well-known Gomphotherium on the following characteristics:

-The enamel bands of Rhynchotherium’s upper tusks spiral to various degrees whilst its mandibular tusks (those on the lower jaw) frequently have enamel bands, which is unique amongst gomphotheres.

Rhynchotherium‘s mandibular symphysis (the plane which serves as a connection point between both sides of the lower jaw in the ‘chin’ region) is slightly deflected downward, unlike that of Gomphotherium (it’s of similar length in both creatures).

He also notes that “Specimens referred to Rhynchotherium range from California east to Florida and from Kansas to Central America, with several specimens known from Mexico…Thus, it can be considered to be a relatively Southern genus, possibly due to a restriction of woodland savanna to this region.”

Rhynchotherium most likely evolved from North American Gomphotherium populations and seems to be most closely akin to fellow American gomphotheres Cuvieronius and Stegomastodon. Carl Buell (aka: Olduvai George) has written in this spectacularly artistic post that “evidence suggests that Rhynchotheres evolved [in Mexico and Central America], [and later] dispersing back to the north”.

Yet another beautiful reconstruction by Olduvai George.

Yet another beautiful reconstruction by Olduvai George.

May the fossil record continue to enchant us all!

P.S.: Lately, I’ve been conversing with my good friend Brian Beatty about possible grad programs for someone interested in Proboscideans and Perissodactylslike myself. I fully realize that, as an undergrad sophomore, this level of my education is fairly far away. However, I feel that it would be wise to evaluate various schools relatively early on in my collegiate career to better prepare myself for when the time comes to choose between them. So far, I’ve begun evaluating the pros and cons of NEOUCOM, The University of Florida, The University of Michigan-Ann Arbor, Columbia University, the University of Nebraska-Lincoln, and The Richard Gilder Graduate School. If anyone has additional suggestions, please don’t hesitate to leave a comment below or e-mail me with your ideas.

A Rhynchotherium lower jaw (minus the mandibular tusks) from Mexico.

A Rhynchotherium lower jaw (minus the mandibular tusks) from Mexico.

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3 responses

15 09 2009
Zach Miller

I (heart) gomphotheres! They are my favorite proboscids! Thanks for writing this fella up–I’d forgotten that not all gomphos are shovel-tuskers.

16 09 2009
tanystropheus

They’re so delightfully bizarre, aren’t they? As for shovel-tuskers, they actually compose under a third of all known gompothere genera.

25 01 2010
A Proboscidean Family Portrait « The Theatrical Tanystropheus

[…] 9= Rhynchotherium tlascalae (which I’ve covered previously here) […]

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