The Manis Mastodon

While growing up in Seattle, I often lamented the lack of dinosaurs from the Pacific Northwest, but I always took some solace in the fact that we had some pretty cool mammal fossils.  I was a regular visitor to the Burke Museum to see the Blue Lake Rhino and the Sea-Tac Sloth, and my family indulged me enough to take me on trips to Ginkgo State Park, Republic, and the John Day Fossil Beds.  One of my particular favorite Northwest fossils was the Manis Mastodon, found near the town of Sequim, on the Olympic Peninsula, because, as a proboscidean, it was big, and therefore akin to the dinosaurs I so desperately wanted to study.  Now, of course, things have come full circle, and I'm living in the Northwest again and studying mammal paleontology.  I have a new appreciation for all the fossils I visited as a child (the John Day fauna has, in fact, become a huge part of my research), and it turns out that one of my old favorites was even more important than I realized.  The Manis Mastodon wasn't just big: it turns out that it's one of the only specimens in North America that preserves evidence of humans butchering a mastodon.  It had long been suspected (at least by some) that a bone point embedded in one of the mastodon's ribs was a broken-off projectile point, which would imply that humans not only scavenged mastodon carcasses, but might have actively hunted them as well.  This hypothesis was recently put to the test by a group of researchers that includes WSU's Carl Gustafson, the scientist that conducted the initial study of the site.  Scans of the rib confirm this hypothesis, but perhaps the most exciting finding of the study was that the Manis site was far older than had been expected: about 13,800 years old.  This revelation has two major implications.  First, it supports the evidence of the so-called "Kelp Highway" hypothesis (the main research focus of Oregon's own Jon Erlandson) that humans populated the Americas by travelling south along the West Coast.  Second, it suggests that humans were hunting large animals prior to the development of stone Clovis points, which may itself have implications for the extinction of the North American megafauna.  The moral of this story?  Never let anyone (even a younger version of me) tell you that there aren't any interesting fossils in the Northwest; as long as our region continues to yield finds like the Manis Mastodon, there will be plenty to keep paleontologists here busy for a long time.

Addendum: Adding to the Manis Mastodon's Northwest cred, Knute Berger, my favorite Seattle journalist has supplied a brief article on the subject.

Fossil Vertebrate of the Month - Terror Bird

This is the largest group of organisms I've ever featured as a FVOTM, but given that we're coming up on Halloween, it seemed appropriate to spotlight a family whose common name is based on how terrifying they were.  Terror birds (or, more correctly, phorusrhacids), represented by the LA County Museum's mount of Paraphysornis in the picture at left, were a group of giant, flightless birds related to living seriemas, most of which have been uncovered in South America.  Flightless birds are not unusual, as anyone who's seen an ostrich, emu, or rhea (or fossils of elephant birds, moas, or mihirungs) can attest.  However, phorusrhacids were different in one key respect: they were carnivorous.  Carnivory has been suggested for some other land birds - chief among them the Eocene Gastornis, itself a possible terror bird ancestor - but the huge size, robust build, and raptor-like beaks of phorusrhacids leave no doubt.  In fact, the near absence of large mammalian carnivores in South America for most of the Cenozoic indicates that the top predator niche on that continent was occupied by terror birds (they would have preyed upon one of the strangest herbivore faunas in the world, composed of, among other things, meridiungulates, xenarthrans, and - somewhat inexplicably - platyrrhine primates and hystricomorph rodents).  Phorusrhacids were key players in the American Biotic Interchange; once thought to have gone extinct when mammalian carnivores (including the iconic Smilodon) moved in from the north, it is now known that terror birds actually expanded onto the Gulf Coastal Plain in North America, where they were represented by Titanis, one of the largest birds ever to have lived (though it was not the largest phorusrhacid - that honor is currently bestowed on the recently-described Kelenken from Argentina).