Reptile fossils solve mystery that has baffled evolutionists

Remains provide link between long-tailed and short-tailed pterosaurs

An extraordinary flying reptile that lived around 160 million years ago has helped scientists to fill a gap in the fossil record that has frustrated scientists since the time of Charles Darwin.

The fossilised remains of more than 20 specimens of the flying reptiles – pterosaurs – were unearthed in China earlier this year. Dating has shown that they fall in the middle of the age range from 220 million to 65 million years ago when the pterosaurs evolved from primitive, long-tailed species to advanced, short-tailed forms.

The latest member of the pterosaurs, which has been called Darwinopterus modularis (Darwin’s wing) in honour of the father of evolution, has provided the first clear evidence for a controversial and unusual mode of evolution whereby entire “modules” of physical traits evolved in unison rather than as individual features.

Pterosaurs, which are sometimes known as pterodactyls, were the first animals with backbones that were known to take to the air in powered flight long before the appearance of the first birds. They had elongated fingers which were used to flap folds of membranous skin stretching to their legs.

They dominated the air when dinosaurs – which belonged to a different group of reptile – ruled the terrestrial environment. During that long period of some 155 million years pterosaurs evolved from predominantly long-tailed forms to short-tailed species but, frustratingly, no intermediate fossils had been found – until now.

The Chinese scientists who discovered and analysed the Darwinopterus fossils worked with British pterosaur expert David Unwin of Leicester University to work out how the species differed from its predecessors and descendants. The researchers concluded that the fossils demonstrate modular evolution, whereby the head and neck have evolved to look more like later species, whereas the long tail retains a more primitive appearance of the earlier pterosaurs.

“Darwinopterus came as quite a shock to us. We had always expected a gap-filler with typically intermediate features such as a moderately elongate tail – neither long nor short – but the strange thing about Darwinopterus is that it has a head and neck just like that of advance pterosaurs, while the rest of the skeleton, including a very long tail, is identical to that of primitive forms,” Dr Unwin said.

Some of the later species of pterosaurs, such as fearsome quetzalcoatlus, grew to gigantic sizes for flying animals, rivalling some of the largest birds today. Darwinopterus, however, was about the size of a crow and its rows of sharpened teeth suggest that it may have caught its prey on the wing.

“The geological age of Darwinopterus and bizarre combination of advanced and primitive features reveal a great deal about the evolution of advanced pterosaurs from their primitive ancestors,” Dr Unwin said.

The rate of evolution in Darwinopterus was probably fast with lots of big changes occurring over a relatively short period of time and, secondly, whole groups of features – modules – appear to have evolved together, although not all modules changed at the same time, he said.

“The head and neck evolved first, followed later by the body, tail, wings and legs. It seems that natural selection was acting on and changing entire modules and not, as would normally be expected, just on single features such as the shape of the snout, or the form of a tooth,” Dr Unwin said.

Pterosaurs died out at the same time as the dinosaurs, about 65 million years ago, when entire groups of animals were also lost in a global mass extinction. But the loss of the pterosaurs and the dinosaurs allowed the rise of the mammals and the birds, which filled the ecological niches on land and air.

“Frustratingly, these events, which are responsible for much of the variety of life that we see all around us, are only rarely recorded by fossils. Darwin was acutely aware of this, as he noted in the Origin of Species, and hoped that one day fossils would help to fill these gaps,” Dr Unwin said.

“Darwinopterus is a small but important step in that direction,” he said. The study is published in the Proceedings of the Royal Society B.

Writer's note:

Originally, there were several sub-editing errors in this piece (including the introduction of the word "carbon" by an over enthusiastic sub) which have been corrected by the author. Apologies.

Steve Connor

Suggested Topics
Start your day with The Independent, sign up for daily news emails
ebooksA special investigation by Andy McSmith
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Chiropractic Assistant

£16500 per annum: Recruitment Genius: A Chiropractic Assistant is needed in a ...

Recruitment Genius: Digital Account Executive - Midlands

£18000 - £26000 per annum: Recruitment Genius: They work with major vehicle ma...

Recruitment Genius: Web Developer

£28000 - £30000 per annum: Recruitment Genius: This company provides coaching ...

Ashdown Group: Front-End UI Application Developer

£30000 - £40000 per annum + Benefits: Ashdown Group: Front-End UI Application ...

Day In a Page

Where the spooks get their coffee fix: The busiest Starbucks in the US is also the most secretive

The secret CIA Starbucks

The coffee shop is deep inside the agency's forested Virginia compound
Revealed: How the Establishment closed ranks over fallout from Loch Ness Monster 'sighting'

How the Establishment closed ranks over fallout from Nessie 'sighting'

The Natural History Museum's chief scientist was dismissed for declaring he had found the monster
One million Britons using food banks, according to Trussell Trust

One million Britons using food banks

Huge surge in number of families dependent on emergency food aid
Excavation at Italian cafe to fix rising damp unearths 2,500 years of history in 3,000 amazing objects

2,500 years of history in 3,000 amazing objects

Excavation at Italian cafe to fix rising damp unearths trove
The Hubble Space Telescope's amazing journey, 25 years on

The Hubble Space Telescope's amazing journey 25 years on

The space telescope was seen as a costly flop on its first release
Did Conservative peer Lord Ashcroft quit the House of Lords to become a non-dom?

Did Lord Ashcroft quit the House of Lords to become a non-dom?

A document seen by The Independent shows that a week after he resigned from the Lords he sold 350,000 shares in an American company - netting him $11.2m
Apple's ethnic emojis are being used to make racist comments on social media

Ethnic emojis used in racist comments

They were intended to promote harmony, but have achieved the opposite
Sir Kenneth Branagh interview: 'My bones are in the theatre'

Sir Kenneth Branagh: 'My bones are in the theatre'

The actor-turned-director’s new company will stage five plays from October – including works by Shakespeare and John Osborne
The sloth is now the face (and furry body) of three big advertising campaigns

The sloth is the face of three ad campaigns

Priya Elan discovers why slow and sleepy wins the race for brands in need of a new image
How to run a restaurant: As two newbies discovered, there's more to it than good food

How to run a restaurant

As two newbies discovered, there's more to it than good food
Record Store Day: Remembering an era when buying and selling discs were labours of love

Record Store Day: The vinyl countdown

For Lois Pryce, working in a record shop was a dream job - until the bean counters ruined it
Usher, Mary J Blige and to give free concert as part of the Global Poverty Project

Mary J Blige and to give free concert

The concert in Washington is part of the Global Citizen project, which aims to encourage young people to donate to charity
10 best tote bags

Accessorise with a stylish shopper this spring: 10 best tote bags

We find carriers with room for all your essentials (and a bit more)
Paul Scholes column: I hear Manchester City are closing on Pep Guardiola for next summer – but I'd also love to see Jürgen Klopp managing in England

Paul Scholes column

I hear Manchester City are closing on Pep Guardiola for next summer – but I'd also love to see Jürgen Klopp managing in England
Jessica Ennis-Hill: 'I just want to give it my best shot'

Jessica Ennis-Hill: 'I just want to give it my best shot'

The heptathlete has gone from the toast of the nation to being a sleep-deprived mum - but she’s ready to compete again. She just doesn't know how well she'll do...