Name: Albertosaurus sarcophagus
Name Meaning: Flesh-eating Alberta Lizard
First Described: 1905
Described By: Osborn
Classification: Dinosauria, Saurischia, Theropoda, Neotheropoda, Averostra, Tetanurae, Orionides, Avetheropoda, Coelurosauria, Tyrannoraptora, Tyrannosauroidea, Tyrannosauridae, Albertosaurinae
Albertosaurus is a relatively famous tyrannosaur, having been depicted in many works of media and being presented often as the smaller cousin of the much more famous Tyrannosaurus. However, this guy was a really neat dinosaur in its own right, and one of my favorites. It is known from a wide variety of fossil specimens, including a bone bed with twenty-two individuals in the same location, and in general it is found in Alberta, Canada, what a huge surprise. It was a large carnivore, up to 10 meters long, and up to 4 meters high. It lived in the Campanian age of the Late Cretaceous, from 71 to 68 million years ago, and should not have crossed paths with Tyrannosaurus. Like Tyrannosaurus, it was a massive bipedal predator, with small arms, and a deep skull, designed to have a huge bite force to better hold struggling prey. It had short bony crests above the eyes that may have been used for display and courtship.
The dry island bonebed featured a huge group of these dinosaurs, with large numbers of bones and many individuals of various ages, including a two year old and a very old, very large individual. This has allowed for a good growth record of the animal to be placed together, with the youngest individual being about 2 meters in length, indicating an S shaped growth curve, with the most rapid growth occurring in a four year period from 12 years old to 16 years old, strangely similar to the human growth curve. Most Albertosaurus that have been found died in adolescence, around 14 years old, with juvenile specimens rarely found, potentially due to small size and fragile bones. There were probably higher infant mortality rates, which has just not been observed due to fossilization bias. Furthermore, the bonebed indicates that these animals may have hunted in packs, given the absence of prey organisms in the bonebed indicating that this site was not a predator trap. They lived in family groups with adults, sub-adults, and juveniles, hunting together and working together to do so - smaller individuals doing more running, larger individuals using more force on prey, filling different niches but working together to hunt.
Albertosaurus lived amongst peat swamps, lagoons, estuaries and tidal flats, as well as deltas and floodplains; a very wet world. It lived alongside many species of fish, mammals, and the plesiosaur Leurospondylus, as well as turtles and crocodilians. It lived alongside many species of dinosaur, especially hadrosaurs such as Edmontosaurus, Saurolophus, and Hypacrosaurus, ceratopsians, ornithomimids, ankylosaurus, pachycephalosaurus, and many other theropods such as troodontids, dromaeosaurids, caenagnathids, and Albertosaurus was decidedly the apex predator of the region.
Shout out goes to my friend crazedcrocgirl!