Dimorphodon was an early, medium-sized flying reptile, or pterosaur, that lived during the Early Jurassic period (approximately 201 to 191 million years ago). Pterosaurs were the first vertebrates to evolve powered flight, and this creature provides important insights into the initial stages of their evolution. Unlike the massive, toothless giants that appeared much later, Dimorphodon was a primitive form with a long tail and a distinct body plan. Its rare fossil remains highlight an early stage in the development of aerial predators.
Naming and Initial Discovery
The first fossil remains were discovered in December 1828 by English collector Mary Anning near Lyme Regis, along the Jurassic Coast in Dorset, England. This initial, incomplete specimen marked the first pterosaur find outside of Germany, which was a significant moment in early paleontology. William Buckland initially classified it as a new species of Pterodactylus, naming it Pterodactylus macronyx in reference to its large claws.
In 1859, British biologist Sir Richard Owen re-examined a more complete specimen, including a skull, and recognized that its features warranted a completely new genus. Owen named it Dimorphodon, derived from the Greek words meaning “two-shaped tooth.” This refers to the creature’s most unusual characteristic: the presence of two distinctly different types of teeth in its jaw.
Defining Physical Features
The most striking feature of Dimorphodon was its disproportionately large and deep skull compared to its relatively compact body. Despite its size, the skull was lightly constructed, featuring several large openings, or fenestrae, which helped to reduce overall weight while maintaining structural integrity. The neck was short, providing a robust base for the heavy head, which measured around 23 centimeters long. The adult animal was approximately 1 meter (3.3 feet) in length, possessing a wingspan estimated to range between 1.45 and 1.7 meters (4.6 to 5.6 feet).
The animal’s heterodont dentition was unlike most other reptiles, which typically have teeth of uniform shape. The front of its jaws contained several pairs of long, fang-like, pointed teeth, perfect for piercing and gripping prey. Further back in the jaw, these were followed by a series of much smaller, flatter, or peg-like teeth. This arrangement suggests an adaptation for catching and processing a varied diet.
Dimorphodon possessed a remarkably long tail, composed of about 30 vertebrae. The tail was stiffened by elongated bony projections. It may have terminated in a vertical, diamond-shaped vane, which would have acted as a rudder for stability during flight. Its hand structure included three prominent claws, which were proportionally large and likely used for climbing.
Habitat and Locomotion
Fossils indicate that Dimorphodon lived in coastal environments of what is now Europe, with the primary finds occurring in the marine sediments of the Jurassic Coast in the United Kingdom. Its habitat was likely a mixture of shoreline, open water, and nearby terrestrial areas, allowing for varied hunting strategies. While initially portrayed as a piscivore (fish-eater), recent biomechanical studies suggest it was a generalist carnivore that likely preyed on small vertebrates and large invertebrates, including insects.
The creature’s locomotion contrasts sharply with the long-winged, soaring flight of later pterosaurs. Dimorphodon had proportionally short wings relative to its body size and a robust skeleton, suggesting it was not built for sustained, long-distance gliding. Instead, its flight was characterized by short, powerful bursts, similar to modern forest-dwelling birds like fowl, used primarily for escaping danger or moving between perches.
On the ground, it is hypothesized that Dimorphodon walked on all four limbs, a stance known as quadrupedal locomotion. The well-developed limbs and large claws on its hands also point to a strong ability to climb. This suggests the animal spent time maneuvering through trees or along rocky cliffs. Its ability to walk and climb effectively, combined with its short-burst flight, indicates an adaptation to a near-shore, terrestrial environment rather than an exclusively oceanic one.