Scott Hanko
Anatotitans
Anatotitan (pronounced /əˌnætɵˈtaɪtən/ ə-NAT-o-TY-tən, "large duck") is a genus of flat-headed or hadrosaurine hadrosaurid ornithopod dinosaur (a "duck-billed dinosaur") from the very end of the Cretaceous Period, in what is now North America. Remains of Anatotitan have been preserved in the Hell Creek and Lance Formations, which are dated to the late Maastrichtian stage of the Late Cretaceous Period, representing the last three million years before the extinction of the dinosaurs (68 to 65 million years ago). This dinosaur is known from at least six specimens pertaining to two species, discovered in the U.S. states of South Dakota and Montana. Several of these specimens are extremely complete skeletons with well-preserved skulls. It was a large animal, up to approximately 12 meters (39 ft) in length, with an extremely long and low skull. Anatotitan exhibits one of the most striking examples of the "duckbill" snout common to hadrosaurs. It has a long taxonomic history, including decades classified with the genera Anatosaurus, Diclonius, and Trachodon.
The skull and skeleton of Anatotitan are well-known. Edward Drinker Cope estimated the length of what is now the type specimen as about 12 meters (38 ft) long, with a skull 1.18 meters long (3.87 ft).[1] This estimate was later revised downward to a length of 8.8 meters (29 ft), although to be fair a dozen vertebrae, the hips, and thigh bones had been carried away by a stream cutting through it, and the tip of the tail was incomplete.[3] A second skeleton currently exhibited next to the type, but in a standing posture, is estimated at 9.1 meters (30 ft) long, with its head 5.2 meters (17 ft) above the ground.[3] The hip height of this specimen is estimated as approximately 2.1 meters (7 ft). Other sources have estimated the length of Anatotitan as approximately 12 meters (39 ft). Anatotitan may have weighed about 3 metric tons (3.3 tons).
The skull of Anatotitan is known for its long, wide muzzle. Cope compared it to that of a goose in side view, and to a short-billed spoonbill in top view. The skull was longer and lower proportionally than in any other known hadrosaurid. The toothless portion of the anterior mandible* was relatively longer than in any hadrosaur. The bones surrounding the large openings for the nostrils formed deep pockets around the openings. The eye sockets were rectangular and longer front to back than top to bottom, although this may have been exaggerated by postmortem crushing. The skull roof was flat and lacked a bony crest, and the quadrate bone that formed the articulation with the lower jaw was distinctly curved. The lower jaw was long and straight, lacking the downward curve seen in other hadrosaurids, and possessing a heavy ridge running its length. The predentary was wide and shovel-like. The ridge on the lower jaw may have reinforced the long, slender jaw.
As mounted, the vertebral column of Anatotitan includes twelve neck, twelve back, nine sacral, and thirty+ tail vertebrae. The limb bones were longer and more lightly built than those of other hadrosaurids of comparable size. Anatotitan had a distinctive pelvis, based on the proportions and form of the pubis bone. Anatotitan, like other hadrosaurids, could move both on two legs and on four legs. It probably preferred to forage for food on four legs, but ran on two. Henry Fairfield Osborn used the skeletons in the American Museum of Natural History to portray both quadrupedal and bipedal stances for Anatotitan.
American Museum of Natural History, New York City, NY.
Anatotitans
Anatotitan (pronounced /əˌnætɵˈtaɪtən/ ə-NAT-o-TY-tən, "large duck") is a genus of flat-headed or hadrosaurine hadrosaurid ornithopod dinosaur (a "duck-billed dinosaur") from the very end of the Cretaceous Period, in what is now North America. Remains of Anatotitan have been preserved in the Hell Creek and Lance Formations, which are dated to the late Maastrichtian stage of the Late Cretaceous Period, representing the last three million years before the extinction of the dinosaurs (68 to 65 million years ago). This dinosaur is known from at least six specimens pertaining to two species, discovered in the U.S. states of South Dakota and Montana. Several of these specimens are extremely complete skeletons with well-preserved skulls. It was a large animal, up to approximately 12 meters (39 ft) in length, with an extremely long and low skull. Anatotitan exhibits one of the most striking examples of the "duckbill" snout common to hadrosaurs. It has a long taxonomic history, including decades classified with the genera Anatosaurus, Diclonius, and Trachodon.
The skull and skeleton of Anatotitan are well-known. Edward Drinker Cope estimated the length of what is now the type specimen as about 12 meters (38 ft) long, with a skull 1.18 meters long (3.87 ft).[1] This estimate was later revised downward to a length of 8.8 meters (29 ft), although to be fair a dozen vertebrae, the hips, and thigh bones had been carried away by a stream cutting through it, and the tip of the tail was incomplete.[3] A second skeleton currently exhibited next to the type, but in a standing posture, is estimated at 9.1 meters (30 ft) long, with its head 5.2 meters (17 ft) above the ground.[3] The hip height of this specimen is estimated as approximately 2.1 meters (7 ft). Other sources have estimated the length of Anatotitan as approximately 12 meters (39 ft). Anatotitan may have weighed about 3 metric tons (3.3 tons).
The skull of Anatotitan is known for its long, wide muzzle. Cope compared it to that of a goose in side view, and to a short-billed spoonbill in top view. The skull was longer and lower proportionally than in any other known hadrosaurid. The toothless portion of the anterior mandible* was relatively longer than in any hadrosaur. The bones surrounding the large openings for the nostrils formed deep pockets around the openings. The eye sockets were rectangular and longer front to back than top to bottom, although this may have been exaggerated by postmortem crushing. The skull roof was flat and lacked a bony crest, and the quadrate bone that formed the articulation with the lower jaw was distinctly curved. The lower jaw was long and straight, lacking the downward curve seen in other hadrosaurids, and possessing a heavy ridge running its length. The predentary was wide and shovel-like. The ridge on the lower jaw may have reinforced the long, slender jaw.
As mounted, the vertebral column of Anatotitan includes twelve neck, twelve back, nine sacral, and thirty+ tail vertebrae. The limb bones were longer and more lightly built than those of other hadrosaurids of comparable size. Anatotitan had a distinctive pelvis, based on the proportions and form of the pubis bone. Anatotitan, like other hadrosaurids, could move both on two legs and on four legs. It probably preferred to forage for food on four legs, but ran on two. Henry Fairfield Osborn used the skeletons in the American Museum of Natural History to portray both quadrupedal and bipedal stances for Anatotitan.
American Museum of Natural History, New York City, NY.