Go fish! Ancient birds evolved specialist diving adaptations

Date:

           May 22, 2015

Source:

Taylor & Francis

Summary:

A new study of some primitive birds from the Cretaceous shows how several separate lineages evolved adaptations for diving. Living at the same time as the dinosaurs, Hesperornithiform bird fossils have been found in North America, Europe and Asia in rocks 65-95 million years old. This research shows that separate lineages became progressively more adept at diving into water to catch fishes, like modern day loons and grebes. 

 

Evolution of diving specializations within the Hesperornithiformes. Credit: Image courtesy of Taylor & Francis

 

A new study of some primitive birds from the Cretaceous shows how several separate lineages evolved adaptations for diving.

Living at the same time as the dinosaurs, Hesperornithiform bird fossils have been found in North America, Europe and Asia in rocks 65-95 million years old. Dr Alyssa Bell and Professor Luis Chiappe of the Dinosaur Institute, Natural History Museum of Los Angeles County, publishing in the Journal of Systematic Palaeontology, have undertaken a detailed analysis of their evolution, showing that separate lineages became progressively more adept at diving into water to catch fishes, like modern day loons and grebes.

The Hesperornithiformes are a highly derived but very understudied group of primitive birds from the Cretaceous period. This study is the first comprehensive phylogenetic analysis, or evaluation of evolutionary relationships, to ever be undertaken on the entire group.

The results of this study confirm that the Hesperornithiformes do form a single group (or clade), but that within this group the inter-relationships of the different taxa are more complex than previously thought. Additionally, this study finds that anatomical changes were accompanied by enlargement in overall body size, which increased lung capacity and allowed deeper diving.

Overall, this study provides evidence for understanding the evolution of diving adaptations among the earliest known aquatic birds.

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Story Source:
The above story is based on materials provided by Taylor & Francis. Note: Materials may be edited for content and length.

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Journal Reference:

1. Alyssa Bell, Luis M. Chiappe. A species-level phylogeny of the Cretaceous Hesperornithiformes (Aves: Ornithuromorpha): implications for body size evolution amongst the earliest diving birds. Journal of Systematic Palaeontology, 2015; 1 DOI: 10.1080/14772019.2015.1036141

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Taylor & Francis. "Go fish! Ancient birds evolved specialist diving adaptations." ScienceDaily. ScienceDaily, 22 May 2015. <www.sciencedaily.com/releases/2015/05/150522105222.htm>.

Little penguins from Australian east and west coasts stick to their own, researchers find

By Laura Beavis

Updated 57 minutes ago

 

Photo: Kangaroo Island is one of the few sites in Australia where penguin colonies from the east and west intermingle. (Supplied: Taronga Zoo)

Little penguins from islands off the south-eastern and south-western coastlines of Australia tend to stick to their own, a 10-year study has found, with one exception - colonies on Kangaroo Island. The scientists from the University of Tasmania, Deakin University in Melbourne, University College London and the Phillip Island Nature Park set out to examine how often little penguins leave and join different colonies.

University of Tasmania zoology lecturer Dr Chris Burridge said they wanted to find out whether penguins would travel from one colony to another to breed. "If a colony was wiped out by a predator, would penguins from other colonies come to help replenish it?" she said.

Over 10 years they took DNA profiles from penguins in colonies along Australia's southern coast from Sydney to Perth and around Tasmania. The researchers found penguins from south-eastern colonies were genetically similar, indicating a high rate of interbreeding among colonies there. The same was true of penguin colonies on the south-west coast.

Around the area of Kangaroo Island you can move only 30 kilometres between two different colonies and they'll be genetically different. ~~~

University of Tasmania zoology lecturer Dr Chris Burridge

Dr Burridge said colonies on Kangaroo Island were different, indicating populations there resulted from breeding between penguins from eastern and western coast colonies. "So in south-east Australia we found quite a lot of movement, you can go from Sydney to southern Tasmania to Phillip Island and the penguin colonies are all genetically indistinguishable," she said. "But then around the area of Kangaroo Island you can move only 30 kilometres between two different colonies and they'll be genetically different."

She said there were several possible explanations for the genetic mixing. "It could be just because that's where the penguins have happened to meet, as they've expanded back out from the east and the west," she said. "Alternatively there could be some activity in that part of the world that removed penguins, maybe anthropogenic and now they've only recently recolonised."

Dr Burridge said the interbreeding on Kangaroo Island had likely begun hundreds or even thousands of years ago. The research has been published in the Journal of Heredity.

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