Dimorphodon was a species of pterosaur that lived during the early Jurassic Period about 195-190 million years ago. It measured over three feet long from its nose to the end of its long tail (which may or may not have terminated with a Rhamphorhynchus-like vane on the end), and it had a wingspan of four and a half feet, making it roughly the size of a large hawk. It’s one of the most easily-recognizable pterosaurs due to the unique appearance of its deep semi-circular head, which measured 9 inches long, one-fourth of its overall body length. It’s because of its head’s unique and recognizable shape that Dimorphodon frequently appears within so many children’s books on prehistoric life alongside other recognizable pterosaur species like Rhamphorhynchus, Pteranodon, and Quetzalcoatlus.
Dimorphodon was one of the first pterosaurs to be classified. Its remains were discovered in Lyme Regis, Dorset, England in 1828 by Mary Anning, and it was officially named the following year by Rev. William Buckland – a man more famous for naming the meat-eating dinosaur Megalosaurus.
Since it was discovered in the early 1800s, several other specimens of Dimorphodon have been found, giving us a good impression of the creature’s anatomy. It’s been suggested that it was a poor flyer and was better suited to gliding rather than active flying. This was partly due to its short wingspan in proportion to body size, and also due to the structure of its feet. Unlike other pterosaurs which had a vestigial fifth toe, Dimorphodon’s fifth toe was greatly elongated, clawless, and oriented sideways. This likely supported a wide skin membrane spanning between the feet and the tail’s base, and would have given Dimorphodon a roughly four-winged appearance similar to the Cretaceous arboreal theropod Microraptor. This extra rear membrane would also have created additional surface area and provided extra lift in order to compensate for the moderate size of the main wings. In this regard, Dimorphodon could be interpreted as a Jurassic reptilian analog of a flying squirrel, swooping from tree to tree and making short-burst flights to catch insects in mid-air.
Although Dimorphodon is mostly associated with England, a partial skeleton was also uncovered in Mexico and was officially described in 1998. This suggests that it had a much wider distribution than previously thought. It’s therefore possible that other Dimorphodon skeletons are waiting to be discovered in other early Jurassic rock layers around the world in places like Massachusetts, Connecticut, New Jersey, Arizona, and southern China, but only time will tell if this is true.
The drawing that you see below was made with No.2, No.3, and Crayola colored pencils on printer paper.
Dimorphodon. © Jason R. Abdale (November 9, 2022).
Keep your pencils sharp, everyone.