Nature gave first ‘face’ to small 419-million-year-old shark named Entelognathus

IS this the first face only a mother could love? Palaeontologists have discovered evolution gave the first “face” to a small shark.

fish

IS this the first face only a mother could love? Palaeontologists have discovered evolution gave the first “face” to a small shark.

This 419-million-year-old fossil belongs to Entelognathus primordialis, an ancient fish that swam the seas off China.

The discovery, detailed in the latest issue of the scientific journal Nature, challenges well established ideas about the separation of cartilaginous fish (such as sharks) and bony fish (which became four-legged creatures).

The debate hinges on the jaw bone.

Established thinking postulates the common ancestor of all jawed animals (gnathostomes) was something like an ancient shark but without the characteristic armoured skull and neck.

Entelognathus turns this thinking on its head.

An artists impression of Entelognathus, an old armoured fish that rewrites the history of human jaw bones. Inset: The fossilised “face”.

It seems, instead, we may all count this 20cm long, heavily armoured fish with a scaly tail among our ancestors.

It has an upper jaw, a lower jaw and cheekbones.

Combined, these give the bizarre-looking Entelognathus history’s first known ``face’’.

The fishy face is made all the more mysterious due to the absence of teeth — something all other known bony fish possess.

Min Zhu, a palaeontologist at the Institute of Vertebrate Paleontology and Paleoanthropology, in Beijing, says he and his team found the fossil near the town of Qujing, in Yunnan, southern China.

“The ... fossil of Entelognathus proved to be something far more bizarre and significant,” Zhu said.