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    Eocarcharia And Kryptops: New Dinosaur Duo From Sahara Ate Like Hyenas, Sharks
    By News Staff | February 14th 2008 01:44 PM | 3 comments | Print | E-mail | Track Comments
    Two new 110 million-year-old dinosaurs unearthed in the Sahara Desert highlight the unusual meat-eaters that prowled southern continents during the Cretaceous Period. Named Kryptops and Eocarcharia in a paper appearing this month in the scientific journal Acta Palaeontologica Polonica, the fossils were discovered in 2000 on an expedition led by University of Chicago paleontologist Paul Sereno.

    Sereno and co-author paleontologist Stephen Brusatte of the University of Bristol say the new fossils provide a glimpse of an earlier stage in the evolution of the bizarre meat-eaters of Gondwana, the southern landmass. “T-rex has become such a fixture of Cretaceous lore, most people don’t realize that no tyrannosaur ever set foot on a southern continent,” said Sereno. Instead, particularly distinctive meat-eaters arose, some of which bore no resemblance to the “tyrant king,” beyond their appetites for fresh meat.

    Full-body portrait of Eocarcharia. Credit: Copyright Todd Marshall, courtesy of Project Exploration.



    Short-snouted Kryptops palaios, or “old hidden face,” was so named for the horny covering that appears to have covered nearly all of its face. “A fast, two-legged hyena gnawing and pulling apart a carcass,” remarked even Brusatte, “is how we might best imagine Kryptops’ dining habits.” Like later members of its group (called abelisaurids) in South America and India, Kryptops had short, armored jaws with small teeth that would have been better at gobbling guts and gnawing on carcasses than snapping at live prey. About 25 feet in length, Kryptops was a voracious meat-eater.

    A similar-sized contemporary, Eocarcharia dinops, or “fierce-eyed dawn shark,” was so named for its blade-shaped teeth and prominent bony eyebrow. Unlike Kryptops, its teeth were designed for disabling live prey and severing body parts. Eocarcharia and kin (called carcharodontosaurids) gave rise to the largest predators on southern continents, matching or exceeding Tyrannosaurus in size. Eocarcharia’s brow was swollen into a massive band of bone, giving it a menacing glare.

    Full-body portrait of Kryptops. Credit: Copyright Todd Marshall, courtesy of Project Exploration.



    “Brow-beating may not be far from the truth,” remarked Sereno. He and Brusatte suggest in the paper that the robust bony brow in Eocarcharia and kin may have been used as a battering ram against rivals for mating rights.

    The fossil area, in present-day Niger, was home to a panoply of bizarre species. The hyena-like Kryptops, the shark-toothed Eocarcharia and the fish-eating, sail-backed Suchomimus (“crocodile mimic”) constitute a meat-eating trio that characterizes the Cretaceous Period in Africa and possibly other southern landmasses.

    They preyed upon the ground-grubbing, long-necked plant-eater Nigersaurus and lived alongside the enormous extinct crocodilian nicknamed “SuperCroc” (Sarcosuchus). Then, the African continent was part of Gondwana and just beginning to free itself of its land connection to South America.

    Funders of the research include the National Geographic Society, The David and Lucile Packard Foundation, the Pritzker Foundation and the Women’s Board of the University of Chicago.

    The scientific paper is available at http://www.app.pan.pl.

    Comments

    Harry Dale Huffman
    Why does the illustration of Eocarcharia look so much like a Tyrannosaurus, if it supposedly "bore no resemblance" to it?
    Because they both theropods and thus share the basic theropod bodyplan, and they are both adapted to the niche of large carnivore.
    Tyrannosaurs are thought to be members of the Coelurosauria, which is a very large group including birds.
    Eocarcharia is thought to belong to the Carnosauria, a group that has Allosaurus in it.
    The split in subgroups in the theropoda is thought to have happened in the early Jurassic, were the Carnosauria adapted to the niche of large carnivores, such as Allosaurus, hunting for large herbivore dinosaurus, such as sauropods. The Coelurosauria adapted to a niche of smaller carnivore (Coelurus, Ornitholestes).
    With the disappearance of Carnosauria from the Northern continents in the Cretaceous, some Coelurosauria filled in the niche of large carnivore, such as the Tyrannosaurids.
    It might be interesting to look whether the disappearance of the Carnosaurs in the North and the continuation in the South might have anything to do with the disappearance of Sauropods in the North, and continuation of Sauropods (titanosaurs for example) in the South.

    All this classification in lineages is of course based features of found skeletons, which are often scarce or incomplete. Remains of large theropods, being top predators, are not as common as herbivore dinosaurs (such as ceratopsia, sauropoda or hadrosauria), and many species are known form only one or two specimens. That's why classifation of large theropods has changed a number of times in the past. This is the best idea we have today of how the lineages are related, but there's always a chance that it is not completely correct.