The Ballad of Atlantosaurus

"Come gather 'round me, people, and listen to the tale

Of Marsh's first big sauropod, its bones now rest at Yale

Atlantosaurus montanus, from Morrison, C-O,

Known from but a sacrum, it was famous long ago"

The majestic Atlantosaurus, next to an elephant that strangely seems to have arrived via 19th century Photoshop. Shamelessly appropriated from Wikipedia, appropriated in turn from De Wereld vóór de schepping van den mensch, Nicolas Camille Flammarion (1886), original title "Le Monde avant la création de l’homme" (1886).

Concerning Brontosaurus

"And I've found/It's all up to what you value" — G. Harrison

By now, the paleontological world has weighed in on the news that Brontosaurus may in fact be a valid genus after all (Tschopp et al. 2015). If you've got some time (befitting its subject matter, it's not what you'd call a short document), the publication is well worth reading. Alternately, if you are strapped for time or just break out in hives when confronted with anatomical terminology, there are many shorter and less technical explorations of the topic. The concise description is that Tschopp et al. ran a number of diplodocid and putative diplodocid specimens through a phylogenetic analysis and then attempted to apply more objective measures than the classic eye test to determine which species should be in which genera. Among the results was the absorption of Dinheirosaurus by Supersaurus, which would make the latter the newest member of the exclusive Morrison–Lourinhã club; the designation of the new genus Galeamopus for longtime problem "Diplodocus" hayi; and the headline finding, that Brontosaurus was distinct from Apatosaurus.

Nautiloids: cephalopod overlords of the Ordovician

The cephalopods include a wide variety of tentacled friends. Today, they are represented by a few species of Nautilus and Allonautilus, and an array of squids, octopuses, and cuttlefish grouped under the subclass Coleoidea. Aside from the nautiloids, with their chambered shells, the modern cephalopods are not great for making fossils. The external shell fell out of cephalopod fashion coincidentally not long after the Cretaceous–Paleocene extinction event eliminated almost all of the practitioners, and although there is a history of internal shells in coleoids, those have been reduced or lost altogether by the smart modern coleoid. They still have more resistant beaks, feeding organs (the radula), and tentacle hooks, with some preservation potential, but otherwise you're looking at a lot of soft tissue. What this means is that most of the groups of cephalopods we see today have wimpy fossil records. On the other hand, we know of a great diversity of extinct shelled cephalopods, from three major lineages. The most famous are the ammonites, best known for coiled forms. They appeared by the middle Paleozoic and left the scene at the end of the Cretaceous. Going extinct at the same time, but apparently only extending back to the Triassic, are the belemnites, a subgroup of the coleoids represented by their bullet-shaped internal shells. Finally, there are abundant extinct forms, primarily from the Paleozoic, lumped together as "nautiloids". These early nautiloids had the run of things from the Ordovician to the Devonian, following which they declined until the lineage that includes modern nautilids was the last branch remaining unpruned at the end of the Mesozoic.

Bivalves

The clam. The oyster. The scallop. The mussel. These are not just names suitable for a low-rank themed superhero or supervillain, but they are also common terms used for some of the abundant and diverse members of the class Bivalvia (also known as Pelecypoda in some references, and Lamellibranchiata if you go back far enough or have a desire to be "that person"). We've already seen the difference between the functional and technical usage of the term "bivalve" with brachiopods, now we get the bivalves that "are" bivalves.

Thescelosaurus: 1999–2015

After about 15 and a half years, I'm no longer going to be maintaining Thescelosaurus.com, expiration date April 9, 2015. It was just one of those things, with a number of reasons behind it. The main one is that I didn't know why I was doing it any more. I'd long ago stopped doing it out of enjoyment and had been doing it out of a sense of obligation. The field of dinosaur paleontology had passed me by years ago, beginning after my graduation from the University of Colorado at Boulder, so I was doing it for enjoyment, and if I wasn't enjoying it, what was the point? The quality of the content was never that hot (I'm not going to claim it was great at the beginning and then declined, because a lot of the initial stuff was pretty hare-brained). As the years went on, the seams resulting from cobbling on this and that were showing, the actual "physical plant" (or whatever the equivalent is for a website) was beyond archaic, and I didn't have the time or, in the end, the desire to bring it up to code. Finally, every year it got a little more expensive, and given the small readership, it occurred to me that I could hear myself talk at cheaper rates.

You'll still be able to find archived versions at Internet Archive, using http://www.thescelosaurus.com/ [later comment: although be very, very careful, because the domain was purchased by other people over the years; the only archives you can be sure are mine predate April 2015, and even then sometimes you get redirected to a more recent version that is very much not mine!], or if you're really desperate, I'm still going to be holding on to the files. Maybe I'll add to them; I don't know. As for alternative sources, I recommend the dinosaur articles at Wikipedia, which at the very least are on par with my own entries and usually much better (and include sources of information), and the Supplementary Information for Thomas R. Holtz, Jr.'s encyclopedia. In particular, the updated versions of the genera list are like mine, only much better. You're welcome to copy the pages for your own use, but I don't want someone else to continue the website because of my concerns with the quality of the content.

I'd like to thank everyone who made a correction, offered a tip, said hello, or found the site to be useful over the years. I'm glad to have had a good long run. I'll still be writing here, so I suppose I'll have to write a bit more often about dinosaurs to make up for it.

Tule Springs Fossil Beds National Monument

I'm sorry about the gap there. I was traveling for work in the Southwest, and was unable to take the time to write anything. Here, though, is a piece about one of the places I saw, albeit briefly: one of the newest National Monuments, Tule Springs Fossil Beds National Monument. This site, north of Las Vegas, was declared in December 2014. It is noted for its abundant Pleistocene fossils, the depth of knowledge concerning its geologic and climatologic history, and historically notable investigations. Having just been established, there are no official National Park Service facilities quite yet.

Looking out across part of the southern end of the monument, facing north-northeast.

Reports of gut contents in herbivorous dinosaurs

I generally avoid writing "nuts and bolts" posts about dinosaurs, because there's a lot of people already doing that who know what they're doing. There is, however, one topic on which I'm uniquely qualified to pontificate. In a previous lifetime I was a fresh-faced graduate student who wrote his thesis on possible gut contents in the "Leonardo" specimen of Brachylophosaurus. As such, I spent a fair amount of time considering the history of possible gut contents in herbivorous dinosaurs, which consists of an exclusive club populated by four hadrosaurs, one ankylosaur, and one sauropod. In retrospect, the Leonardo project was somewhat beyond my powers, but I battled on against overwhelming oddities and came out of it eventually. (For you folks playing along at home, by "herbivorous dinosaurs" I mean more or less classic dinosaurs that aren't theropods. I've got nothing against birds, which include many a herbivorous dinosaur, but they aren't why I got interested in these things, and I don't feel sentimental about them being dinosaurs, because "my" dinosaurs are almost all ornithischians and have all been dead for 66 million years.)