Tag Archives: Cretaceous

Know Your Bones: February 2016

Last month’s challenge must not have been as challenging as I thought. The correct answer was given by WarK within an hour of the blog going up.


Deinonychus antirrhopus


This critter is indeed Deinonychus antirrhopus.


 photo 2015-12-11 12.19.12_zpssnatmoko.jpg
(Taken at the New Mexico Museum of Natural History and Science)


Deinonychus lived during the early Cretaceous 115 to 108 million years ago. Deinonychus stood ~87 cm at the hip, reached ~3.4 meters in length, and weight ~73 kilograms. Deinonychus lived in what is now the modern western U.S. with possible fossils of it found in eastern states. Deinonychus belongs to the dromaeosaurid clade. Deinonychus (meaning terrible claw) is named for the claw found on the second toe of each foot. This claw was retractable, meaning that it kept it off the ground so it would remain sharp for the animal’s entire life. It also had three sharp claws found on each hand.


Bite marks from Deinonychus have been found on herbivorous dinosaurs. Measuring the amount of force needed to puncture the bone reveals that Deinonychus had a bite strength roughly the same as an American alligator. It is believed that Deinonychus lived and hunted in packs. Working together, they would have been able to take down much larger animals. The first Deinonychus specimen discovered is what reignited the idea that birds were closely related to dinosaurs in the 1960s. Since than, it is now believed (based on specimens of closely related animals) that Deinonychus also possessed feathers; in fact, the whole dromaeosaurid clade could have possessed feathers.


Moving on to next month’s challenge:


 photo 2013-10-04112707_zpse725be22.jpg
(Taken at the New Mexico Museum of Natural History and Science)


Above is the last Know Your Bones challenge I will be doing for a while. I am going to focus this blog in a different direction. I just wanted to finish off with this specimen, because it is one of my favorites.

Know Your Bones: July 2015

I chose last month’s challenge believing it would be a tricky one. However, I was truly impressed by the answers given, although none of them were correct, but the knowledge of prehistoric critters the readers of this blog possesses impresses me. I truly thought everyone would simply guess Triceratops and move on. As I said, this is not Triceratops, nor any of the ceratopsians given in the comments. Thus, this once again makes me the winner of this month’s challenge for stumping everyone.


However, the critter that owned the skull in last month’s challenge was Pentaceratops sternbergii and I will give you five guesses as to what its name means.


 photo Dayatthemuseum001_zps5d38b135.jpg
(Taken at the New Mexico Museum of Natural History and Science)


Pentaceratops lived during the Cretaceous 75 to 73 million years ago. It is mostly found in New Mexico and Colorado (U.S.). It would have reached a length of ~8 meters and weighed ~5,500 kg. Pentaceratops had five horns, two large horns over the eyes, one small horn over the nose, and two small horns, which protrude sideways out of under the eyes. Pentaceratops also possessed a large frill with two large fenestrae in it. The fenestrae found on the frill were most likely away for cutting down the weight of the skull. Pentaceratops specimens include some of the largest skulls of all terrestrial animals. The frill and horns were most likely used for display, with the possibility of blood being pumped into the frill to change its color slightly. The frill and horns were also probably used in defense as well as jousting between each other.


Pentaceratops belongs to the ceratopsian clade. That clade also belongs to the ornithischian clade, meaning that Pentaceratops and the other ceratopsians are more closely related to hadrosaurids and thyreophorans than they are to saurischians. Pentaceratops is believed to be an herbivore and thought to have traveled in large herds similar to modern bovines. Another striking feature Pentaceratops possesses is its sharp beak, which was most likely used for ripping open large and tough vegetation or digging into the ground for tubers.


Moving on to next month’s challenge:


 photo IMAG0167_zps074c8041.jpg
(Taken at the Denver Museum of Nature and Science)


Here is an easy one, since last month’s challenge ended up being so difficult. I am looking for the critter on the left, since the critter on the right was already featured. Good luck to all that participate.

Know Your Bones: April 2015

Last month’s challenge appeared to be no challenge to League of Reason’s resident rockhound Isotelus. She gave the correct answer within a day of the blog going up.


Edmontosaurus annectens. They’re like the cockroaches of Alberta’s fossil megafauna. Dig a hole and you’re probably going to find at least a piece of one. :P


This critter is indeed Edmontosaurus annectens and it is indeed an extremely common fossil.


 photo 2015-02-06 11.39.14_zpsd3bsgwtu.jpg

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


Edmontosaurus lived during the Cretaceous 73 to 65.5 million years ago. They ranged widely across western North America, seemingly living along the Western Interior Seaway. Edmontosaurus belong to the hadrosaurid clade, which are popularly called duck-billed dinosaurs. Edmontosaurus belongs to a crestless group of hadrosaurid, unlike a previous “Know Your Bones” challenge. The specimen used in last months blog is actually famous for having what appears to be a bite mark on its tail from a Tyrannosaurus.


Edmontosaurus reached a length of ~13 meters (the skull alone was ~1 meter long) and could weigh up to 4 tons, making them one of the largest hadrosaurids to have ever lived. As a means of locomotion, Edmontosaurus were likely able to walk on all fours or on just their hind limbs. Edmontosaurus is also famous for having several skin impressions, which allows us to know what most of the skin of this animal looked like in life. Edmontosaurus had teeth that grew in columns of six teeth, and had around 50 columns in each jaw. The teeth were continually replaced throughout the animal’s life. However, the beak of an Edmontosaurus was toothless and was extended by a keratinous material, much like modern birds.


Moving on to next month’s challenge:


 photo 2015-01-09133458_zps29f325f9.jpg

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


Good luck, as always.

Know Your Bones: December 2014

Last month’s challenge was not very challenging seeing as how Isotelus was able to give the correct answer within hours of when the blog was posted. She said it gave her some trouble, but I actually highly doubt that.


Partial skull of Parasaurolophus. I would say P. tubicen because the crest is a bit different from P.walkeri, and it’s definitely not P. cyrtocristatus. Also it’s from New Mexico so it makes sense to be in the NM museum. SCIENCE.


This skull did indeed belong to Parasaurolophus tubicen, which stands for trumpeter-crested lizard.


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


Parasaurolophus are extremely rare animals in the fossil record. There are three species known to science found in Alberta (Canada), New Mexico (USA), and Utah (USA). In each area, only a few specimens have been found and all specimens are incomplete. P. tubicen is only known from New Mexico with three specimens discovered. Parasaurolophus lived during the Late Cretaceous 76 to 73 million years ago. P. tubicen reached a size of ~9.5 meters in length and weighed ~ 2.5 tons. P. tubicen was an herbivore and most likely walked on four legs, but was able to run, walk, and brows on its hind limbs.


Even though it is rare, it is still one of the most famous dinosaurs, and that is most likely due to the eye-catching aspect of P. tubicen. The crest that grows from the rear of its skull is fairly unique. The crest is hollow and allowed air to be pushed through it. This would have allowed P. tubicen to make very loud trumpeting noises. The crests were also most likely colorful and could have acted as visual displays. P. tubicen would have filled the Late Cretaceous with beautiful music while communicating with one another over large areas. P. tubicen belongs to the hadrosaurid clade, which is one of the most famous ornithischian clades as well.


Moving on to this month’s challenge:


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


Good luck to everyone that plays.


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.