This is a short music video about Hylonomus.
Ecology of earliest reptiles inferred from basal Pennsylvanian trackways
Trackways representing the earliest evidence for the origin of reptiles (amniotes) are reported from the basal Pennsylvanian Grande Anse Formation, New Brunswick, Canada. Amniote characters include pentadactyl manus and pes, slender digits whose relative lengths approximate a phalangeal formula of 23453 (manus) and 23454 (pes), narrow digit splay (40–63°), putative transverse scale impressions on digit pads, and straight tail drag. The trackways occur in the deposits of a seasonally active dryland river channel. Sedimentological context suggests, for the first time, that early amniotes existed in water-stressed environments, where the cleidoic egg would have presumably conferred reproductive advantage.
According to Dutch daily NRC of 18 October 2007, the tracks are probably by the early lizard-like reptile Hylonomus lyelli. And they are about 315 million year old, over a million years older than that species was thought to be so far.