As we've seen from time to time with packrat middens, there are many ways of looking at past ecological conditions. A common method in more humid environments that the deserts and mountains of the Southwest is studying lake deposits, which is quite well-suited to the Land of 10,000 Lakes. Many types of paleoecologically useful fossils can be extracted from lake sediments, ranging from diatoms ("algae" with silica cell walls), to spores and pollen, to mollusks, to ostracodes, to the jaw parts of certain midge larvae. (There are, of course, other kinds of fossils that can be found in lakes, but they aren't as commonly used for paleoecological work. A single mammoth, while certainly of great interest, is not as versatile for this kind of thing as innumerable pollen grains spread over thousands of years.) Spores and pollen are part of a group of fossils known as palynomorphs, organic-walled microfossils. There are several other types of palynomorphs, including various cysts and so forth, but for the purposes of upper Pleistocene and Holocene lake sediments in Minnesota, spores and pollen are clearly the stars of the show.
Sunday, January 29, 2017
Sunday, January 22, 2017
A couple of new publications concerning mammoths in National Park Service units have crossed my desk recently, so it seemed like a good opportunity to say a few further words on behalf of extinct proboscideans in the National Parks. I present to you first the finely wrought map below, which shows the various parks where body fossils of mammoths, mastodons, and their friends have been reported. At press time, there were 37 parks, monuments, and so forth with confirmed records, and another six with possible records (cases where the locality is not clear). This map has the novelty of differently colored and shaped symbols, which aside from providing a splash of color, show a preponderance of mastodons in the northeast and mammoths in the southwest. I've relied on the literature and such, so there's definitely the chance that some of the "mammoths" are mastodons, and vice-versa. Most of these records are from the Pleistocene, but there are a few that are older; notably, John Day Fossil Beds National Monument and Niobrara National Scenic River have both gomphotheres and mastodons of pre-Pleistocene age. The great majority of the mammoth reports in the lower 48 are likely Columbian mammoths, Mammuthus columbi (M. exilis of Channel Islands National Park being a notable exception), but given the ambiguities in North American mammoth taxonomy, I figured it wasn't worth the time to try to split them up.
Sunday, January 15, 2017
|Sorry, but I don't seem to have a better picture of local hyoliths, unless the things mentioned in this post or this post are hyoliths.|
This week, the big paleontological news had nothing to do with dinosaurs, or mammals, or anything with bones at all for that matter. Instead, hyoliths got to be the subject of dozens of news articles, for the happy reason that their relationships are no longer quite so enigmatic. Undergrad Joseph Moysiuk of the University of Toronto and colleagues have presented research on the little guys showing that they were equipped with a tentacle-laden feeding apparatus, making them next cousins to...
Sunday, January 8, 2017
Making predictions about paleontology is kind of awkward, at least if your predictions are based on what is published. Because there's usually five to ten years between a discovery and its publication, there's often a sense of what is out there, just not when it will appear. After all, we've got abstracts, press releases, photos on social media, etc... But what the hey? We're just having fun (hopefully). Lots of links to names are included in case you're mostly here for the Ordovician and aren't familiar with the lingo. Below are my predictions for dinosaur paleontology in the year 2017, after the photo of actual dinosaurs taken at much expense and personal risk via a secret and unfortunately now-lost technology.
|Actual photo from the late Campanian of Canada. Things were surprisingly geometric then. Note that dinosaurs in their natural environment kind of hang around as if they are on coffee break, instead of constantly being on murderous rampages.|