Tag Archives: Jurassic

Know Your Bones: October 2015

There were only two guesses for last month’s challenge, both correct, but one being more correct. I have a feeling that the reason only two people guessed is because this one was such an easy specimen. So, who won, who was the more correct of the two?




It turned out to be WarK, because the other guesser gave the wrong species name. The critter from last month is Camarasaurus supremus.


 photo 2014-01-10111738_zps5a90e232.jpg
(Taken at the New Mexico Museum of Natural History and Science)


Camarasaurus lived during the late Jurassic 155 to 145 million years ago. It ranged across most of North America and is an extremely common dinosaur in the Morrison Formation. Camarasaurus had an average length of 18 meters and weighed up to 18 tons. Remarkably, several complete skeletons of Camarasaurus have been discovered in Wyoming, Colorado, Utah, and New Mexico. Based on their fossil abundance it is assumed that they roamed around North America in large numbers during the late Jurassic and may have had one of the largest populations of sauropods, if not dinosaurs, known thus far.


Camarasaurus means “chambered lizard;” it most likely got this name from the hollow bones that make up much of the vertebra or the many fenestrae found on the skull. Camarasaurus had chisels shaped teeth that were 19 cm long. The shape of the teeth and strength of the skull suggest that Camarasaurus specialized in eating coarser plant matter. This is different from other sauropods, thus Camarasaurus most likely inhabited a different environment then its cousins that also lived during this time. Camarasaurus remains are found together in a lot of sites, suggesting that they lived and died in herds.


Moving on to this month’s challenge:


 photo 2013-10-18105402_zps59c3c2eb.jpg
(Taken at the New Mexico Museum of Natural History and Science)


Here we have a terrifying critter, which is appropriate for this month. Thanks for playing and good luck.

Know Your Bones: August 2015

Last month’s challenge sparked a great discussion about the fenestrae found on the skull of some dinosaurs. By the end of it, we had come up with two or three different projects for Isotelus to work on. The discussion was so involved that only one person guessed on the actual challenge.


PS The dinosaur in this month’s challenge is Allosaurus. As you said, it was easy! :D


Dragan Glas is correct; this critter is Allosaurus.


 photo 2014-01-10111750_zps802d443e.jpg
(Taken at the New Mexico Museum of Natural History and Science)


Allosaurus fragilis lived during the late Jurassic from 155 to 145 million years ago. The average length of an Allosaurus was 8.5 meters (however, some fragmentary remains have been interpreted as being ~12 meters) and weighed in at ~2.3 tons. Allosaurus possessed a large skull ~84 cm in length, which was lightly built, with ~20 pairs of teeth on both the top and bottom jaw. The teeth of Allosaurus were constantly being replaced throughout the life of the animal, making their teeth very common fossils. The skull also had a pair of small horns above the eye. The purpose of the horns is unknown, but could be related to display, combat against other Allosaurus, or just keeping the sun out of the eye of the animal. Allosaurus possessed short (for its size) forearms that had three fingers, which had strong, large curved claws. The forearms were very powerful and most likely used for hunting.


Allosaurus was one of the largest predators of the Jurassic and would have prayed upon a number of different dinosaurs. Allosaurus is one of the best-understood theropods (perhaps dinosaurs) we have ever discovered. In the Cleveland-Lloyd Dinosaur Quarry (Utah, USA) alone there are at least 46 different individuals of Allosaurus discovered. This quarry has individuals ranging from multiple age groups, from specimens that are less than a meter in length on through full-grown adults. This has allowed paleontologists to reconstruct a wonderful life history for Allosaurus.


Moving on to this month’s challenge:


 photo 2015-07-24 13.40.46_zpsoy9kf1zp.jpg
(Taken at the New Mexico Museum of Natural History and Science)


I am not looking for a specific species name this week (but major props to anyone that can do that), but what are these specimens examples of? Good luck to everyone that participates.

Know Your Bones: March 2015

Last month’s challenge was extremely easy. Thus, I did not just want the name of the critter, but why it was such an important critter as well. With in a matter of hours Inferno named the critter, and about a day later edited his post to say why it was so important.


Archaeopteryx lithographica

EDIT: Why is it important? Because Darwin predicted it. There was no link between birds and dinosaurs, then Archaeopteryx showed up. In Darwin’s lifetime.


This critter is indeed Archaeopteryx lithographica and Inferno is correct that it fulfilled a prediction Darwin made within a few years of the prediction being made.


 photo 2014-01-10111452_zps436afe7e.jpg

(Taken at the New Mexico Museum of Natural History and Science)


Archaeopteryx lived during the late Jurassic, 150 to 145 million years ago in southern Germany. During that time, Europe was located close to the equator and was a large archipelago of islands in a shallow ocean. Archaeopteryx was not a very large animal, reaching 50 centimeters in length. Even though Archaeopteryx is popularly known as the first bird, it has a lot more in common with other theropods (especially the dromaeosaurs). Some of those features are a mouth full of teeth, three un-fused finger bones that included claws on each, a long bony tail, and feathers. One of the features that Archaeopteryx possesses that aligns it with birds is the atypical flight feathers found on its arms and legs. The feathers suggest that Archaeopteryx could at least glide if not outright fly. Scans of the skull of Archaeopteryx shows that it had a larger brain, including a larger vision center, than most other dinosaurs at the time, which also suggest gliding/flight capabilities.


The fossil used in last month’s challenge is known as the Berlin Specimen, and it is the most famous specimen of Archaeopteryx (and one of the most famous fossils in the world). However, the reason it is the most famous specimen is because it is the most complete, not because it was the first specimen found. The first skeletal remains of Archaeopteryx were found in 1861 and are known as the London Specimen. The London Specimen is missing a head, so the skull anatomy of Archaeopteryx was not known until the discovery of the Berlin Specimen in 1880, and its discovery further fulfilled Darwin’s prediction.


Moving on to this month’s challenge:


 photo IMAG0176_zpsd11161e7.jpg

(Taken at the Denver Museum of Natural History and Science)


Good luck and have fun.

Know Your Bones: January 2015

Last month’s challenge appeared to give everyone a hard time since it went a whole two days before someone took a guess. However, after a few days of silence, Isotelus once again correctly named this critter.


Rhamphorhynchus muensteri


This critter is indeed Rhamphorhynchus muensteri.


(Taken at The New Mexico Museum of Natural History and Science)

R. muensteri lived during the late Jurassic 156 to 145.5 million years ago. Its fossils are found in Germany, with several possible specimens of Rhamphorhynchus found in England, Spain, and Tanzania. R. muensteri reached a size of ~1.26 meters from snout to tail with a wingspan of ~1.81 meters. However, the smallest known specimen is a (hatchling) ~290 millimeters in length, but would have still been capable of flight. R. muensteri was a long-tailed genus of pterosaur, and was less specialized than the contemporary short-tailed pterosaurs.


R. muensteri had needle-like teeth that were forward facing, the tip of its beak was sharp and curved up, and lacking teeth. When the jaws were closed, the teeth fit together like a closed zipper. This suggests that R. muensteri had a diet mostly made up of fish and other marine animals. Adult R. muensteri had a diamond-shaped vane at the end of their tail, which possibly was used to signal for mates; the diamond-shaped vane does not appear on smaller specimens assumed to be juveniles, and their beaks are not as sharp and curved.


Moving on to next week’s challenge:


(Taken at The New Mexico Museum of Natural History and Science)


Good luck to everyone who is playing and I promise that this one will be the last difficult one for a while.

Know Your Bones: July 2014

Last month’s challenge is a true titan. It held the record for being the largest dinosaur for several decades. So, who was able to name this giant? Isotelus once again named this critter.


 Brachiosaurus. I would guess the species name starts with an ‘a’ :P


This is indeed Brachiosaurus altithorax.



(Taken at the New Mexico Museum of Natural History and Science)


Brachiosaurus roamed 145 to 150 million years ago, during the Jurassic (and possibly the early Cretaceous) across the Western U.S. Brachiosaurus shared its range with several other sauropods and an earlier Know Your Bones critter. Brachiosaurus was ~25 meters in length, ~13 meters tall, and it had an estimated weight of ~28 tons, making it a true giant by any standard. Unlike most other dinosaurs, Brachiosaurus had longer forelegs than their hind legs. This curious trait is where it gets its genus name from (Brachiosaurus literally means, “arm lizard”).


Brachiosaurus was an herbivore, most likely feeding off the tops of fern trees that the other sauropods could not reach. Its large body would have been more than enough protection from predators that lived at the same time. It probably took a Brachiosaurus ten years to reach full size and could eat up to (if not more) ~182 kg of plant matter a day as an adult.


Moving on to this month’s challenge:



(Taken at the Dinosaur Museum and National Science Lab)


Good luck to all.

Know Your Bones: May 2014

Last month’s challenge was extremely easy, so easy in fact that just an hour after being posted Inferno gave a correct answer. However, and this seems to be a theme for this series, WarK posted an even more correct answer a few hours later.


 Stegosaurus stenops

I’m guessing with the latter part of the name. From what pictures I could find online that one looked the closest to the picture posted by the Bone Torturer


This is indeed Stegosaurus stenops, a very famous dinosaur.



(Taken at the New Mexico Museum of Natural History and Science)


Stegosaurus ranged across most of western North America during the late Jurassic 150 to 145 million years ago, and one specimen was discovered in Portugal. Stegosaurus is found in the Morrison Formation in North America. Stegosaurus stenops could reach a size of ~7 meters in length, although some species of Stegosaurus could reach lengths of ~9 meters. This sounds impressive, but one has to remember that Stegosaurus would have been dwarfed by the sauropods found at the same time and place.



(Taken at the New Mexico Museum of Natural History and Science)


There are two main branches of dinosaur, ornithischians (“bird” hip) and saurischians (“lizard” hip). Stegosaurus belongs to the ornithischian clade. This means that Stegosaurus possesses a pelvis that superficially resembles a modern bird pelvis. Stegosaurus also belongs to the Thyreophora (armored dinosaur) clade. This clade includes all the dinosaurs that had armored backs and tales. The plates found on the back of Stegosaurus and the spikes on its tale make Stegosaurus one of the easiest dinosaurs to identify. The spikes on its tale were most likely exclusively used as defensive weapons against the predators of its time. However, the plates on the back of Stegosaurus may have been used for thermal regulation as well as defense. The plates show blood vessels ran across their surface. This could have also been used for colorful displays when blood was pumped into them.


Moving on to this month’s challenge:


(Taken at the New Mexico Museum of Natural History and Science)


Good luck.