Few animals are as iconic and mysterious as the Dimetrodon. Often mistaken for a dinosaur, Dimetrodon was actually a primitive synapsid – also known as pelycosaur – that pre-dated the earliest dinosaurs by 50 million years. This prehistoric “mammal-like reptile” is more closely related to our mammalian ancestors than to the archosaurs that spawned the dinosaurs.
It featured a hard palate, and like humans, single openings in the skull behind each eye known as temporal fenestrae. The ridges on the inside of its nasal cavity eventually transitioned to supporting mucous membranes that warmed and moistened incoming air, a sign of warm-bloodedness. A ridge at the back of the lower jaw, called the reflected lamina, which would later develop into part of a ring called the tympanic annulus that supports the ear drum in all living mammals.
Dimetrodon had a very successful predator design, evidenced by its 40 million year expanse in the fossil record and wide geographical distribution including Canada, Germany, and across North America. The most prominent feature of the Dimetrodon is its massive sail, consisting of elongated vertebral spines. It is theorized that in life this would have been covered by skin, and functioned as a thermoregulatory device or mating display. Aside from the potential advantage of controlled thermoregulation, Dimetrodon had differentiated teeth, hence the reason for its name (“two measures of teeth“). These consisted of teeth designed for grabbing its prey, and serrated teeth designed for shearing flesh. Dimetrodon was likely to be one of the apex predators of the Cisuralian ecosystems, feeding on fish and tetrapods, including amphibians and small reptiles such as Captorhinus.
Its reign ended with the Permian–Triassic extinction event, the most extensive extinction event ever recorded, that saw 90% to 95% of marine species and 70% of all land organisms become extinct. It is also the only known mass extinction of insects.
This ultra-rare original Dimetrodon specimen, believed to be the first of its kind in SE Asia, was discovered in the Wellington (Ryan) Formation of Jefferson Country in Oklahoma, USA. It finally arrived in Singapore in three shipments after over a two-year wait required for the prospector to prep the specimen. We christened him Dilbert, after the white collar comic strip that also on occasion featured dinosaurs.
Welcome to Singapore Dilbert! Here he is reunited in a face-off with a Captorhinus, a small reptile that Dimetrodon is believed to have fed on from the same wetland ecosystem.