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I was reading a paper Fruitbat just posted in his fantastic PDF library, on sauropods see below, and it triggered a concern that I've had for a while for collectors purchasing claws. First let me preface the discussion by saying I'm not a sauropod expert just throwing out some observations and questions. Identifying claws is not an easy diagnosis. Sellers typically put a name, mostly at a genus level, on claws they sell. I have several in my collection and boy they are indeed hard to distinguish between families. Here is a seller offering a juvenile Diplodocus foot claw from the Morrison formation. So is this a juvenile? or just one of the smaller claws from a hand or foot? Also, what's so diagnostic about this claw that one can claim it's from a Diplodocus? A museums view of Diplodocus foot Then there Apatosaurus not much different. I personally believe trying to identify isolated sauropod claws to family level is very difficult since there is very little diagnostic about them. Its a non starter for most except for the most knowledgeable in the field. Issues like age of individual, position in the foot, distortion and preservation make a diagnosis very hard. Here is a seller doing it the right way calling his specimen just Sauropod. I think if your interested in purchasing a claw that you're interested in having a positive ID it needs to be done with an associated foot since they are diagnostic. Another possibility is knowing that a claw came from a Quarry that is predominantly from one type of Sauropod. Here is a seller doing exactly that, selling an Apatosaurus foot. The paper that started this post has a couple of nice views of Camarasaurus feet/claws that you can use for comparative purposes. Tschopp, E., et al. (2015). Articulated bone sets of manus and pedes of Camarasaurus(Sauropoda, Dinosauria). Palaeontologia Electronica, 18.2.44A.

South of Hanksville, UT... I have been to this spot a few times and I know others go frequently. This was the first time I noticed the petrified wood and bone. Most are in the rock and easy to see but there are more coming up through the eroding dirt. It was pretty cool. I have many pictures, but the files are too big.

I have an Allosaurus premax tooth, and I was wondering, is it possible to narrow its age down to a time gap that is smaller than 10 million years? For example, Allosaurus lived from 156 to 146 million years ago, but can the age be determined more specifically (other than radioactive isotope dating)? If it's in any help, my tooth came from Bone Cabin quarry, Albany County, Wyoming. Don't worry if you can't help though, it's not a big deal, I'm just curious if it is possible to determine determine the exact age of the fossil with the information I have

Has there been any latest word on the taxonomic status of the following taxa described by Cope: Brachyrophus Symphyrophus Tichosteus lucasanus Caulodon As far as I can recall, Brachyrophus and Symphyrophus were listed as synonyms of Camptosaurus in both editions of the Dinosauria, but the recent recognition of the Dinosaur National Monument camptosaur as distinct from Camptosaurus raises questions about whether or not Brachyrophus and Symphyrophus are synonymous with Camptosaurus (one reference lists Symphyrophus a possible synonym of the Jurassic crocodile Amphicotylus). The status of Tichosteus relative to other ornithopods is also an open question, given that Carpenter (1998) lists the type species of Tichosteus as questionably ornithopod (although the uncertain systematic position of Drinker and Othnielosaurus within Neornithischia may make Tichosteus an indeterminate neornithischian at best), while listing T. aequifacies as a possible synonym of the turtle Glyptops. As for Caulodon, the synonymy of that genus with Camarasaurus by Osborn and Mook (1921) may be questionable because other basal macronarians have the same tooth shape as the teeth named Caulodon and the teeth of Camarasaurus and USNM 5730 (which includes craniodental remains) was not considered macronarian at the time of the paper by Osborn and Mook (1921). Carpenter, K., 1998, Vertebrate biostratigraphy of the Morrison Formation near Cañon City, Colorado: Modern Geology, v. 23, p. 407-426.