3D model of a Primitive Snake Fossil (NHMW-GEO-1912/0001/0008)

<p>3D scan of a fossilized specimen of&nbsp;<em>Pachyophis woodwardia</em>&nbsp;– an extinct marine snake found in Bilek, Bosnia and Herzegovina and is dated 100 million years ago. Its thick ribs acted like lead weights to counter its buoyancy in the water. Although significantly different from modern snakes, this holotype was correctly identified in 1923 by its first scientific describer, the naturalist Baron Nopcsa (1877–1933).</p><p>Land-living four-legged reptiles were the ancestors of the marine saurian from which the marine snake <em>Pachyophis</em> evolved. In the Cretaceous period (around 145 to 65 million years ago), while <em>Pachyophis</em> was swimming in the oceans, its relatives were conquering the land.&nbsp;The evolution of snakes shows that the evolution of an order is not
always in one specific direction. The repeated transitions from water to
land and back also left traces in the skeleton, although these are not
always unambiguous.&nbsp;The thickened bones weighed down the animal and therefore helped it to
stay underwater. This shows that the animal was probably semi-aquatic.&nbsp;<em>Pachyophis woodwardia</em> was most likely a predator that fed on small aquatic animals.&nbsp;Primitive snakes like <em>Pachyophis</em> died out at the end of the
Mesozoic era, and modern snakes only returned to the sea in the latest
chapter of the Earth’s history, the Neogene (around 23 to 20 million
years ago).</p>