Ear analysis suggests Archaeopteryx was more birdlike than reptilian

January 14th, 2009 - 12:44 pm ICT by ANI  

Washington, Jan 14 (ANI): A new research has suggested that the earliest known bird, Archaeopteryx, had a similar hearing range to the modern emu, which suggests that the 145 million-year-old creature, despite its reptilian teeth and long tail, was more birdlike than reptilian.

The research was done by a team of paleontologists and biologists from London, Munich and Ohio.

Using innovative modern technology, the team has shown for the first time how the length of the inner ear of birds and reptiles can be used to accurately predict their hearing ability and even aspects of their behavior.

In modern living reptiles and birds, we found that the length of the bony canal containing the sensory tissue of the inner ear is strongly related to their hearing ability, said study co-author Paul Barrett, a palaeontologist at Londons Natural History Museum.

We were then able to use these results to predict how extinct birds and reptiles may have heard and found that Archaeopteryx had an average hearing range of approximately 2000 Hz. This means it had similar hearing to modern emus, which have some of the most limited hearing ranges of modern birds, he added.

Researchers previously have only been able to estimate how prehistoric animals heard by examining the skulls of damaged fossils and relating brain region size to hearing ability, based on comparisons to the animals modern relatives.

Computed tomography or CT imaging, however, allowed the team to accurately reconstruct the inner ear anatomy of various intact bird and reptile specimens.

Fifty-nine species were studied, including turtles, crocodiles, snakes and birds.

By examining the three dimensional CT scans we were able to see for the first time the real relationship between hearing ability and behavior in extinct reptiles and birds, said Stig Walsh, Natural History Museum palaeontologist and lead author on the study.

The size of the cochlea duct (the bony part of the inner ear housing the hearing organ) in living birds and reptiles accurately predicts the hearing ranges of these animals. This simple measurement can therefore provide a direct means for determining hearing capabilities, and possibly behavior, in their extinct relatives, including Archaeopteryx, he added.

According to Angela Milner, also from the Natural History Museum, Our previous research has shown that the part of the ear that controls balance was just like that of modern birds, and now we know that Archaeopteryx had bird-like hearing too. (ANI)

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