Episode 158 is all about Camarasaurus, a sauropod whose name means “chambered lizard.”

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In this episode, we discuss:

News:

The dinosaur of the day: Camarasaurus

Sauropod that lived in the Jurassic in what is now the Morrison Formation, in North America

Name means “chambered lizard”

Had hollow chambers in its vertebrae

First found in 1877, by Oramel W. Lucas, in Colorado

Named by Edward Drinker Cope in 1877, who paid for the bones (all during the Bone Wars)

Three valid species: Camarasaurus supremus, Camarasaurus grandis, Camarasaurus lentus

Type species is Camarasaurus supremus (the originally named species, whose name means “the biggest chambered lizard”)

Other species include Camarasaurus grandis (“grand chambered lizard,” named in 1877), Camarasaurus lentus, named in 1889

Othniel Charles Marsh later named some sauropods Morosaurus grandis, but these are now considered to be Camarasaurus

There was also Camarasaurus lewisi, which was named in 1988 and originally classified as Cathetosaurus. But in 2013 another study split the two genera again

Camarasaurus synonyms include Caulodon, Morosaurus, Uintasaurus

One of the most commonly found sauropods

Lots of Camarasaurus skulls have been found

Cope wasn’t the best record keeper, and he labeled some Camarasaurus fossils (now at AMNH) with letters and numbers, to correspond with a set of dig site sketches. But he threw away the dig site sketches, so it’s not clear what he meant (some copies have been found, but not enough)

Brontosaurus was originally given a Camarasaurus skull (Brontosaurus is a diplodocid, so it’s skull was more likely elongated and narrow, and not so boxy)

Charles W. Gilmore found a nearly complete skeleton of Camarasaurus in 1925 (a young Camarasaurus, so drawings from that time depict Camarasaurus as smaller than we now know it is)

Camarasaurus is a basal macronarian, a group of sauropods that kept their heads up high and include Brachiosaurus,‭ ‬Giraffatitan, Lusotitan

Camarasaurus grandis is the oldest species

Camarasaurus lentus and Camarasaurus grandis probably co-existed for several million years, and were slightly different so probably filled slightly different ecological roles

Camarasaurus grandis disappeared, then Camarasaurus lentus disappeared, around the same time Camarasaurus supremus appeared, which may mean Camarasaurus supremus evolved from Camarasaurus lentus

Only difference between Camarasaurus supremus and Camarasaurus lentus is that Camarasaurus supremus was larger (also, it was found in the upper parts of the formation, so it’s the newest Camarasaurus)

Camarasaurus lentus could grow up to 49 ft (15 m) long

Camarasaurus supremus could grow up to 75 ft (23 m) long and weigh up to 47 tons

Had pneumatic bones, with air sacs in the vertebrae that connected to the lungs

Forelimbs were shorter than the hindlimbs

Had five toes, and sharp claws on its feet

For a while, it was thought that Camarasaurus had a second brain (had an enlarged space by the hips), but this is no longer thought to be true

Probably had a stiff, muscular neck

Probably traveled in herds or groups of families, based on two adults and a juvenile that were found to have died together, from drowning while crossing a flooded river

Probably didn’t take care of its young, like other sauropods, based on nests found with Camarasaurus eggs found in lines (not arranged nicely, and the eggs may have been laid near undergrowth so hatchlings could run for cover)

Charles Marsh at one point thought that Camarasaurus gave live birth (like sharks, which develop eggs in the body and give live birth), but there’s no evidence for this

Had a blunt snout and a squarish, arched skull

May have had a beak. No evidence has been found yet, but some Camarasaurus teeth have been found in the lower jaws that are not connected to the jaw bone exactly but were preserved in the right place (may have been because of soft tissue that kept them there); a beak would also have helped it shear through plants

Had spatulate teeth

Teeth were strong, could probably eat tough vegetation

Probably held its neck up high, and was a high browser

One Camarasaurus specimen found had evidence of soft tissue (the gums), which show that Camarasaurus probably had gums covering all but the tips of the crowns of its teeth. The specimen is nicknamed “ET” because when it was first found all you could see was a finger bone coming out of the rock

Probably did not swallow gastroliths, instead, had strong teeth that were replaced about every 62 days (so may have chewed its food)

Vegetation at the time included ferns, conifers, green algae, fungi, mosses, horsetails, cycads, and ginkoes

Lived in a semiarid environment with wet and dry seasons

Also lived among snails, fish, frogs, salamanders, turtles, lizards, crocodylomorphs, pterosaur-like animals, and early mammals

Other dinosaurs that lived among Camarasaurus include Diplodocus, Apatosaurus, Brachiosaurus, ornithischians such as Camptosaurus, Stegosaurus, Dryosaurus, theropods like Saurophaganax, Torvosaurus, Ceratosaurus, Ornitholestes, and Allosaurus

A partial Camarasaurus grandis skeleton found in 1992 at the Bryan Small Stegosaurus Quarry of the Morrison Formation was found to have pathologies that would have made it difficult to move its forelimb (a lesion on the bone that looks to be made of woven bone fibers). It probably healed but with a growth that would have made it difficult to forage for food and escape predators. Pathology may have been caused by an avulsion injury (part of the bone and its muscle attachment was ripped from the rest of the bone), according to McWhinney and others, which may have been because of a slip or fall, or repetitive strain (that Camarasaurus may have lived in an area of uneven ground)

A Camarasaurus pelvis found in Dinosaur National Monument in Utah shows signs of Allosaurus bites (Allosaurus did not necessarily kill the Camarasaurus, instead it may have eaten the Camarasaurus after it died)

One Camarasaurus specimen was prepared and put on exhibit at the 1933 World’s Fair, and is now on display at the Smithsonian National Museum of Natural History in Washington, D.C.

A mounted Camarasaurus, lent from the Smithsonian, was on display at the Dallas Federal Building as part of the 1960 expo to celebrate Texas’ 100th birthday

Can see a Camarasaurus at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania

Can see a Camarasaurus in situ at Dinosaur National Monument

Only two skulls left on the quarry face at Dinosaur National Monument are of Camarasaurus (can also see the neck bones of one)

Fun Fact:

Mammals were probably mostly nocturnal until dinosaurs went extinct. This may have resulted in a “nocturnal bottleneck” giving modern mammals some nocturnal features including: Large eyes that favor low light to precision, a broad range of hearing, a better sense of smell, and whiskers.

Sponsor:

This episode is brought to you in part by TRX Dinosaurs, which makes beautiful and realistic dinosaur sculptures, puppets, and exhibits. You can see some amazing examples and works in progress on Instagram @trxdinosaurs