Posts Tagged ‘theropods’

Know Your Bones: March 2016

he_who_is_nobody
he_who_is_nobody
Tue Mar 08, 2016 6:05 pm by he_who_is_nobody

Last month’s challenge went unguessed, meaning the final bragging rights for Know Your Bones belongs to me.

 

So, what is the name of the critter in last month’s challenge? It is Coelophysis bauri.

 

 photo Dayatthemuseum082_zps3be8952d.jpg
(Taken at the New Mexico Museum of Natural History and Science)

 

Coelophysis bauri lived during the late Triassic 208 to 228 million years ago. Most specimens are found in New Mexico, however, several specimens of related species (specimens that would be classified as Coelophysis) have been found worldwide, dating to as late as the early Jurassic. Coelophysis is one of the earliest dinosaurs known to science and the earliest known from complete specimens. Coelophysis was ~3 meters in length and would have stood ~1 meter at the hip. Coelophysis is a theropod with sharp curved teeth. It possessed four fingers on its forelimbs, which is the basal trait for theropods. It is believed that Coelophysis was a fast and agile predator.

 

 photo 2013-03-03091919_zpsaa913bc8.jpg
(Taken at the New Mexico Museum of Natural History and Science)

 

Coelophysis is one of the earliest dinosaurs discovered, being named by Edward Drinker Cope in 1889. Coelophysis means “hollow form,” because Cope noticed that it possessed hollow bones, something shared with all later theropods. Coelophysis also possessed a furcula (i.e. a wishbone) and a sclerodic ring seen in the orbit of the skull. The sclerodic ring allowed for muscle attachments which would have given Coelophysis amazing vision, much like modern birds of prey. As pointed out above, Coelophysis is one of the earliest dinosaurs and it already had all these traits that are found in modern birds. It would not be surprising to find out that Coelophysis also possessed feathers.

 

 photo 2013-07-26113514_zpsc84222fd.jpg
(Taken at the New Mexico Museum of Natural History and Science)

 

Thank you for everyone that ever participated in this. I did enjoy it, but I feel my time is better spent blogging about a different subject.

Know Your Bones: February 2016

he_who_is_nobody
he_who_is_nobody
Mon Feb 08, 2016 1:29 pm by he_who_is_nobody

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: November 2015

he_who_is_nobody
he_who_is_nobody
Sat Oct 31, 2015 9:31 pm by he_who_is_nobody

I have to say, I am surprised it took so long for anyone to take a stab at guessing this iconic fossil. By the trepidation of our winner and the following guesser, perhaps the readership of this blog finds me to be a trickster. With that said what critter once owned the skull from last month’s challenge?

 

Something tells me this is too easy to be correct.

 

Nope WarK, I was not trying to trick anyone. This critter is indeed the tyrant king of the dinosaurs, Tyrannosaurus rex.

 

 photo IMAG0555_zpsa92a2380.jpg
(Taken at the New Mexico Museum of Natural History and Science)

T. rex lived during the late Cretaceous 68 to 65 million years ago; it also happened to be one of the last non-avian dinosaurs that we know about. It ranged across western North America, with its fossils (mostly teeth) found from Alaska down to Mexico. T. rex could grow as large as ~4 meters at the hip, 43 meters long and weigh between 5.5 to 6.8 tons. This makes T. rex one of the largest predatory dinosaurs and one of the largest predators to ever walk the earth. Full-grown animals had a skull ~1.5 meters in length. The teeth of T. rex ranged from 30 cm long (including the root) to 13 cm long (including the root) in adults. The teeth would have been continuously replaced during life and were re-curved with ridges on the surface. T. rex famously has small arms (about the length of an adult human’s arm) with only two fingers. However, the arms appear very muscular, leading paleontologists to speculate that the arm could have been used for something (e.g. assisting in lifting the animal up when it sat down) instead of just a vestigial structure.

 

 photo 2013-10-04111227_zps27b761c7.jpg
(Taken at the New Mexico Museum of Natural History and Science)

 

Over 30 specimens of T. rex have been discovered to date, making T. rex a very well studied dinosaur. T. rex is a theropod, but within that clade, it is closer in relation to dromaeosaurs than it is to other giant carnivores, such as Allosaurus. Because of this, and fossil finds of earlier relatives, it is possible that T. rex could have had feathers. However, a few skin impressions has only shown scales, which leads some to speculate that  T. rex could have had full body feathering as a hatchling, but later sparse to no feathering as an adult due to its large size.

 

 photo 2015-10-30 09.59.06_zpsabkivlad.jpg
(Taken at the New Mexico Museum of Natural History and Science)

 

Two possible footprints have been found of T. rex, one of which was found in New Mexico. It measures 83 cm by 71 cm and possesses a “heel” print plus the print of the dewclaw-like forth digit found on the feet of T. rex. T. rex is also famous for being the first dinosaur found with soft tissue associated with it. In 2005, Dr. Mary Schweitzer published her discovery of it, since than several more finds have been made of soft tissue. Dr. Schweitzer and others have found trace soft tissues, and when they are analyzed and compared to living organisms, it shows that T. rex’s closest living relatives are birds. These findings align with the conclusions paleontologists were making for decades based on morphology.

 

Moving on to next month’s challenge:

 

 photo Dayatthemuseum015_zps0c57051f.jpg
(Taken at the New Mexico Museum of Natural History and Science)

 

Good luck to all that play.

Know Your Bones: August 2015

he_who_is_nobody
he_who_is_nobody
Mon Aug 03, 2015 7:55 pm by he_who_is_nobody

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

he_who_is_nobody
he_who_is_nobody
Tue Mar 03, 2015 11:57 am by he_who_is_nobody

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.

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