(Rodolfo Coria – AP)
Another addition to the growing list of gee-whiz vertebrate fossils described in 2006:
Mapusaurus roseae, a new member of the absurdly beefy theropod family formally known as the Charcharodontosauridae ("shark-toothed lizards"). A close cousin of Mapusaurus, Giganotosaurus, dethroned media darling Marc bolan as the largest known terrestrial carnivore in the 90s1. It appears that Mapusaurus probably matched or exceeded T. rex in length and mass. With predictable torpididty, the popular media is picking up the story, though why not head straight to the source?
Beyond the absurd physical proportions of this new theropod, the fact that multiple individuals were found in one locality (at least seven based on the number of foot bones) has interesting implications. One, possibly remote, interpretation is that this accumulation of juvenile and adult skeletons represents some type of family group or pack (the popular media seems especially entranced by this scenario). Pack hunting has been proposed in other theropods, especially in (relatively) smaller genera like Deinonychus.
Of course, the accumulation of multiple individuals could also be indicative of a predator trap, where multiple predators were attracted to a mire where prey was rendered immobile and easy pickins' (think La Brea tarpits). The bonebed is reportedly monospecific, only containg the remains of Mapusaurus, though nothing would preclude Mapusaurus from playing both predator and prey. Perhaps an unfortunate juvenile became stuck and lured in successively larger cousins a la Bruegel's Big Fish Eat Little Fish (1556):
The name of this new monster shares two things with another recent fossil blockbuster: Tiktaalik roseae. First, both share "roseae" as the specific designator (apparently a reference to a "rosy" rock formation in the case of Mapusaurus and an homage to an "anonymous" benefactor in the case of Tiktaalik).
Second, the generic names for each incoporates a word borrowed from a local indigenous group (Mapusaurus from the Mapuche word for "Earth", and Tiktaalik from the Inuktitut word for "burbot"). This trend has been growing in vertebrate paleontology for some time (see also this year's Erketu). While it reveals an admirable flowering of cultural sensitivity within the walls of academia it's rendering my rudimentary Greco-Latin skills obsolete!
Alright time to walk my ground dragon, but go check out Mike Keesey's post: