It had a pair of longitudinal, plate-shaped crests on its skull, similar to a cassowary with two crests. The function of the crests is unknown; they were too weak for battle, but may have been used in visual display, such as species recognition and sexual selection.
The skull of Majungasaurus is exceptionally well-known compared to most theropods and generally similar to that of other abelisaurids. Like other abelisaurid skulls, its length was proportionally short for its height, although not as short as in Carnotaurus.
Alectrosaurus was a very fast running tyrannosauroid as indicated by the elongated hindlimbs that likely filled the niche of a pursuit predator, a trait that seems to be lost by the advanced and robust tyrannosaurids.
Dimorphodon means "two-form tooth", derived from the Greek δι (di) meaning "two", μορφη (morphe) meaning "shape" and οδων (odon) meaning "tooth", referring to the fact that it had two distinct types of teeth in its jaws – which is comparatively rare among reptiles.
Primitive characters for Tyrannosauroidea are the elongate neck vertebrae and the long, well-developed arms forelimbs along with the undecorated dorsal surface of the skull, unlike the more advanced tyrannosaurids.
The creature also makes effective use of razor-sharp claws to latch onto surfaces such as the trunks of tall trees, holding its position indefinitely. Warlike tribes appear to consider Tapejara the equivalent of a versatile rotor aircraft, capable of rapid positional changes and aggressive agility.
The skull had a pair of horns above and in front of the eyes. The horns were probably covered in a keratin sheath and may have had a variety of functions, including acting as sunshades for the eye, being used for display, and being used in combat against other members of the same species.
Early meat-eating dinosaurs like Coelophysis relied on their speed and agility to catch a variety of animals like insects and small reptiles. The sharp teeth and grasping claws of Coelophysis would have helped them to hold and kill their food.