Feath­ers may have evolved in lizards be­fore birds

The Sligo Champion - - LIFESTYLE -

The pe­cu­liar-look­ing crea­ture in the il­lus­tra­tion above is a pterosaur, a mem­ber of a group of fly­ing lizards that be­came ex­tinct some 66 mil­lion years ago. Pterosaurs did not have flight feath­ers and wings like mod­ern birds; their wings were more like those of fruit bats with a mem­brane of skin stretch­ing from their an­kles to their fin­gers. They were the first back-boned an­i­mals to evolve true flap­ping flight.

Sev­eral pterosaur species, like the one above, were furry rather than be­ing en­tirely scaly like mod­ern lizards. And while they lived side by side with them from 230 to 66 mil­lion years ago, pterosaurs were not di­nosaurs but were a dis­tinct group of their own.

The il­lus­tra­tion is by Yang Zhang from China’s Nan­jing Uni­ver­sity and is fea­tured in the cur­rent is­sue of the jour­nal Na­ture Ecol­ogy and Evo­lu­tion. The draw­ing is based on a re­con­struc­tion of the fly­ing lizard from two ex­cep­tion­ally well pre­served fos­sils found in the Dao­hugou fos­sil beds in north-east­ern China near In­ner Mon­go­lia.

The beau­ti­fully-pre­served fos­sils were es­ti­mated to be 160-165 mil­lion year old. Ex­am­i­na­tion of the de­tail pre­served in them showed that the lizard had four dif­fer­ent feather types over its gin­ger-brown head, neck, body, and wings: sim­ple fil­a­ments or ‘ hairs’, bunches or bun­dles of fil­a­ments, fil­a­ments with a tuft half­way down, and down feath­ers.

The sig­nif­i­cance of the fos­sil find is that it pushes the ori­gin of feath­ers back 70 mil­lion years ear­lier than hereto­fore un­der­stood and sug­gests that feath­ers may have first evolved in lizards rather than in birds. How­ever, the early rudi­men­tary feath­ers were short, fuzzy and hair-like, so they could not have been used for flight; it ap­pears more likely that they, like fur, were used for in­su­la­tion against the cold.

It is be­lieved that the fos­sil pterosaur had a wing­span of about 45cm, big­ger than that of a Black­bird but smaller than a Jack­daw. It is likely that it lived in wood­lands and prob­a­bly fed on in­sects. Some pterosaurs, like the ptero­dactyls, had wing­spans in ex­cess of 10m and were the sharks of the an­cient skies.

About 66 mil­lion years ago, an as­teroid struck Earth with such dev­as­tat­ing force that it led to the mass ex­tinc­tion of all pterosaurs, ptero­dactyls and di­nosaurs.

The study of the lizard’s feath­ers was led by re­searchers from Nan­jing Uni­ver­sity in China, Dr Maria McNa­mara and Prof Pa­trick Orr from Uni­ver­sity Col­lege Cork, and Prof Mike Ben­ton from the Uni­ver­sity of Bris­tol.

Pterosaurs were a group of fly­ing lizards that had a cov­er­ing of the ear­li­est-known feath­ers.

Newspapers in English

Newspapers from Ireland

© PressReader. All rights reserved.