Alectosaurus (Greek, "alone lizard") was a Primitive Tyrannosaurid from Late Cretaceous China and Mongolia, around 83 to 74 mya. It was a small tyrannosaurid; which was 16.4 feet (5 meters) long, 8 feet (2.5 meters) in height and weighed 1000 lbs. It is only known from a partial skeleton, and is likely a primitive fast-running tyrannosaurid. Its fossil was found in the Gobi Desert in Mongolia. It had sharp teeth, and was a bipedal carnivore. It was named after a mythical deity, Alectra, by C. W. Gilmore in 1933. The animal's official Scientific Name is: Alectrosaurus olseni.
Discovery and naming
Alectrosaurus was a species of medium-sized, moderately built Theropod. The length of its tibia (lower leg bone) and femur (thighbone) are very close, in contrast to the majority of other tyrannosauroids, where the tibia is longer. The hind foot (and ankle) are also closer in size to the tibia than in most other tyrannosauroids, where the hind foot is usually longer.
In 1933, Charles Gilmore examined the available material and concluded that AMNH 6554 and AMNH 6368 were syntypes belonging to the same genus. He based this on his observation that the manual unguals from both specimens were morphologically similar. Observing similarities with the hindlimbs of specimen AMNH 5664 Gorgosaurus sternbergi, he classified this new genus as a "Deinodont", a term that is now considered equivalent to tyrannosaurid. Due to its fragmentary nature, there is presently very little confidence in restoring its relationships with other tyrannosauroids and many recent cladistic analyses have omitted it altogether. One study recovered Alectrosaurus at no less than eight equally parsimonious positions in a tyrannosauroid cladogram.
Alectrosaurus was originally characterized as a long-armed theropod Dinosaur, but Mader and Bradley in 1989 observed that the forelimbs (AMNH 6368) did not belong to this individual and assigned them to the Segnosauridae. The remaining material, AMNH 6554 represents the hind limb of a true tyrannosauroid, and were assigned as the lectotype for Alectrosaurus olseni. Mader and Bradley also described and assigned caudal vertebrae AMNH 21784 to this genus. These researchers concluded that Alectrosaurus was closely related to Maleevosaurus novojilov based on hind limb proportions.
- Alectrosaurus Makes its first media appearance in the final episode of Planet Dinosaur. A Pair of Alectrosaurus shown to assault a pair of Gigantoraptors to got into their nest; also, likely, for the territorrial skirmishes.