Ramon Posted March 15, 2020 Share Posted March 15, 2020 Hello, this spring break I found this vertebra in late Campanian sediments from southern Coahuila, Mexico. It comes from the Late Campanian, Cerró del Pueblo Formation, around 73-71 million years. This was found along with marine and terrestrial fossils. It is about 1 cm long (3/8) of an inch, 1 cm in width, and 1.1 cm in height. I want to know what type of dinosaur this vertebra belonged to and whether it’s a caudal vertebra or not. My thoughts on this specimen at the moment, is that it’s probably a caudal (tail) vertebra from a small theropod dinosaur, something like a dromeosaur or a troodontid. I hope some dinosaur experts on this forum can give me more insight on this small vertebra.. Side view Other side Front view Bottom Top view 3 "Without fossils, no one would have ever dreamed that there were successive epochs in the formation of the earth" - Georges Cuvier Link to comment Share on other sites More sharing options...
Troodon Posted March 15, 2020 Share Posted March 15, 2020 Looks like a caudal vertebra from an indeterminate hadrosaurid. Very Nice centrum. 5 Link to comment Share on other sites More sharing options...
Ramon Posted March 15, 2020 Author Share Posted March 15, 2020 2 minutes ago, Troodon said: Looks like a caudal vertebra from an indeterminate hadrosaurid. Wow, I would’ve never thought this came from a hadrosaur given the small size of the specimen. Could it be from an infant hadrosaur? What are the differences between hadrosaur and theropod caudal vertebrae? "Without fossils, no one would have ever dreamed that there were successive epochs in the formation of the earth" - Georges Cuvier Link to comment Share on other sites More sharing options...
Troodon Posted March 15, 2020 Share Posted March 15, 2020 I have small ones in my collection. Distal Caudals can get quite small and yes most likely a juvie. Hadro centrums have a rectangular cross section and are boxey...not typical of theropod. 3 Link to comment Share on other sites More sharing options...
Ramon Posted March 15, 2020 Author Share Posted March 15, 2020 What about the Pleurocoels? “Saurischian dinosaur vertebrae sometimes possess features known as pleurocoels, which are hollow depressions on the lateral portions of the vertebrae, perforated to create an entrance into the air chambers within the vertebrae, which served to decrease the weight of these bones without sacrificing strength.” - Martin, A.J. (2006). Introduction to the Study of Dinosaurs. Caudal vertebra of the theropod Aerosteon riocoloradensis showing pleurocoel (pl) and a smaller septum (se) Photograph from “Evidence for Avian Intrathoracic Air Sacs in a New Predatory Dinosaur from Argentina” My vertebra I haven’t found any literature on other dinosaur groups other than theropods having Pleurocoels. What are y’alls thoughts on this? 1 "Without fossils, no one would have ever dreamed that there were successive epochs in the formation of the earth" - Georges Cuvier Link to comment Share on other sites More sharing options...
Troodon Posted March 15, 2020 Share Posted March 15, 2020 I do not believe those are pleurocoelus, tendon attachment points. "Pl" are typically larger and oval like the one in your illustration 3 Link to comment Share on other sites More sharing options...
dinosaur man Posted March 15, 2020 Share Posted March 15, 2020 Cool find 1 Link to comment Share on other sites More sharing options...
Ramon Posted March 15, 2020 Author Share Posted March 15, 2020 9 minutes ago, dinosaur man said: Cool find Thanks!! It’s the first dinosaur fossil I’ve found. Ever since I was a kid I’ve been fascinated by these creatures, and I’m very happy I finally found something interesting. 1 "Without fossils, no one would have ever dreamed that there were successive epochs in the formation of the earth" - Georges Cuvier Link to comment Share on other sites More sharing options...
dinosaur man Posted March 15, 2020 Share Posted March 15, 2020 3 minutes ago, Ramon said: Thanks!! It’s the first dinosaur fossil I’ve found. Ever since I was a kid I’ve been fascinated by these creatures, and I’m very happy I finally found something interesting. Agreed dinosaurs are amazing creatures!! 1 Link to comment Share on other sites More sharing options...
jpc Posted March 16, 2020 Share Posted March 16, 2020 yes, hadrosaur. Adult. I have seen a noce articulated hadrosaur tail, and the vertebrae get very small in the end. So yes, any size can be an adult animal. 2 Link to comment Share on other sites More sharing options...
Ramon Posted March 16, 2020 Author Share Posted March 16, 2020 44 minutes ago, jpc said: yes, hadrosaur. Adult. I have seen a noce articulated hadrosaur tail, and the vertebrae get very small in the end. So yes, any size can be an adult animal. Thanks for the information!! "Without fossils, no one would have ever dreamed that there were successive epochs in the formation of the earth" - Georges Cuvier Link to comment Share on other sites More sharing options...
LordTrilobite Posted March 16, 2020 Share Posted March 16, 2020 I agree with Troodon and Jpc. Typical Hadrosaur caudal vert. Here's an Edmontosaur caudal vert from my collection for reference. Though it's a little more subtle on your specimen, notice the hexagonal shape of the centrum. 2 Olof Moleman AKA Lord Trilobite Link to comment Share on other sites More sharing options...
Ramon Posted March 17, 2020 Author Share Posted March 17, 2020 I know this vertebra’s owner has been identified as a hadrosaurid, but I have one more question. Could the holes in the vertebra be from predation/scavenging? I have been reading on this hadrosaur caudal vertebra from Coahuila, Mexico. It has a hole which is a result from predation by a Deinosuchus crocodile. My specimen 1 "Without fossils, no one would have ever dreamed that there were successive epochs in the formation of the earth" - Georges Cuvier Link to comment Share on other sites More sharing options...
jpc Posted March 17, 2020 Share Posted March 17, 2020 look for the semi lunar crushing marks. Its a shame the photo of the Mexican bone are note bigger so that we can see what the authors are talking about. Google it, maybe 2 Link to comment Share on other sites More sharing options...
Ramon Posted March 17, 2020 Author Share Posted March 17, 2020 It’s hard to know what the authors are talking about. I took closer pictures of the 2 largest puncture holes. The largest one is 1.5 mm long and about 2nmm deep. They are small compared to other bite marks I’ve seen. What do you guys think? Could it have been made by some small scavenger? Largest puncture hole 1 "Without fossils, no one would have ever dreamed that there were successive epochs in the formation of the earth" - Georges Cuvier Link to comment Share on other sites More sharing options...
LordTrilobite Posted March 17, 2020 Share Posted March 17, 2020 4 hours ago, Ramon said: I know this vertebra’s owner has been identified as a hadrosaurid, but I have one more question. Could the holes in the vertebra be from predation/scavenging? I have been reading on this hadrosaur caudal vertebra from Coahuila, Mexico. It has a hole which is a result from predation by a Deinosuchus crocodile. My specimen Notice that the example I posted from my collection also has a little hole on the left side, bottom half. It's probably just a blood vessel opening or nutrient foramen or something like that. The size and shape varies quite a bit between vertebrae and individuals as well. I do not think these are predation marks. They look rounded and natural imo. I don't think those holes are particularly odd or anything. Seems perfectly normal to me. 2 Olof Moleman AKA Lord Trilobite Link to comment Share on other sites More sharing options...
jpc Posted March 18, 2020 Share Posted March 18, 2020 I do not see the crushing scars of a predator bite. I agree... nutrient foramen of some sort. This photo shows good predator crushed wounds... from the unoversiity of Nebraska web site https://news.unl.edu/newsrooms/today/article/museum-preparators-dig-into-history-of-fossil-finds/ 2 Link to comment Share on other sites More sharing options...
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