hylonomus

“This piece is a spectacular summary of the age (Carboniferous) as one dominated by enormous, bizarre-looking plants, with Sigillaria looming imposingly from behind a tangled veil of tree ferns. The dramatically leaping animal in the foreground is Hylonomus, the earliest known definitive reptile. While I realise I gush about Henderson non-stop, this truly is one of his masterpieces; I only wish I had an enormous print of it to hang on my wall.”

Mark Vincent at Love in the Time of Chasmosaurs

Meganeura, Robert Back, 2007

Meganeura does not hum or buzz, rather its lace-and-glass wings hiss and whisper, fluttering like paper caught in an electric fan, susurrating like a pinwheel whirling in a breeze. It does not move randomly. Each spiral and zig-zag, each aerial pivot and dive is a calculated part of the hunt. Trajectories are adjusted, targets are pinpointed—one must stay clear of the prey’s eyesight. When the ambush comes, lizard-like Hylonomus hears the wing-shiver for just a split second before being folded into the insect’s arms and consumed while still alive.

The forest dweller, Hylonomus (1851)

Phylum : Chordata
Class : Reptilia
Subclass : Eureptilia
Genus : Hylonomus
Species : H. lyelli

  • Carboniferous (315 - 312 Ma)
  • 20 cm long (size)
  • North America (map)

It’s always possible that a more ancient candidate will be discovered, but as of now, Hylonomus is the oldest true reptile known to paleontologists: this tiny critter scuttled around the forests of the Carboniferous period over 300 million years ago. Based on reconstructions, Hylonomus certainly looked distinctly reptilian, with its quadrupedal, splay-footed posture, long tail, and sharp teeth.

Hylonomus is also a good object lesson in how evolution works. You might be surprised to learn that the oldest ancestor of the mighty dinosaurs (not to mention modern crocodiles and birds) was about the size of a small gecko, but new life forms have a way of “radiating” from very small, simple progenitors. For example, all mammals alive today–including humans and sperm whales–are ultimately descended from a mouse-sized ancestor that scurried beneath the feet of huge dinosaurs more than 200 million years ago.