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Curassow

life science Maturity 5-7 Next article →

Curassows are a fascinating group of large birds. They belong to the cracid family.

Mitu tuberosa Whaldener Endo
Mitu tuberosa Whaldener Endo

Within this family, curassows are the largest species by body size. Scientists classify this distinct group as the subfamily Cracinae. Most of these birds live in the tropical regions of South America. However, one specific species of the genus Crax lives much further north. It can be found as far north as Mexico.

Nothocrax urumutum -head -zoo-8a
Nothocrax urumutum -head -zoo-8a

To understand how these birds changed, scientists study molecular data. This involves looking at mtDNA and nDNA, which are types of DNA sequences. These genetic codes act like a history book for living things. By analyzing these sequences, researchers can see how different lineages diverged from one another. This data suggests that curassows split from their closest living relatives long ago. Those relatives were likely guans.

Pauxi pauxi -Denver Zoo, Colorado, USA -head-8a
Pauxi pauxi -Denver Zoo, Colorado, USA -head-8a

The history of the curassow began during the Oligocene epoch. This was a time roughly 35 to 20 million years ago. While this molecular data is very helpful, scientists consider it preliminary. They hope to find more evidence in the form of fossils to confirm these dates. Current research shows that curassows likely originated in the lowlands of the Amazonas basin. This specific area is near the borders of Brazil, Peru, and Colombia.

Hocofaisán (8708251591)
Hocofaisán (8708251591)

Curassows are divided into two major evolutionary lineages. The first lineage contains only the genus Crax. The second lineage is made up of the genera Mitu and Pauxi.

Mitu tuberosa Whaldener Endo
Mitu tuberosa Whaldener Endo

There is also a peculiar nocturnal curassow. Its exact position in the family tree is not yet fully resolved. It might be more closely related to the Mitu and Pauxi group. It likely diverged around the same time the two major lineages split.

Further changes happened during the Tortonian age of the early Late Miocene. The different genera began to separate during this period. The initial split occurred about 10 to 9 million years ago. Later, the Pauxi genus diverged from the Mitu genus. This specific separation happened between 8 and 7.4 million years ago. Many of these changes were caused by vicariant speciation. This occurs when groups of animals are separated by new geographic barriers.

There are many different types of curassows to discover. The genus Pauxi includes helmeted curassows. Examples include the Northern Helmeted Curassow and the Southern Helmeted Curassow. The genus Mitu contains birds like the Crestless curassow and the Razor-billed curassow.

Pauxi pauxi -Denver Zoo, Colorado, USA -head-8a
Pauxi pauxi -Denver Zoo, Colorado, USA -head-8a

The genus Crax is also very diverse. It includes the Great curassow, the Blue-billed curassow, and the Black curassow. Some species are much rarer than others. For example, the Alagoas curassow became extinct in the wild during the mid-to-late 1980s.

Studying curassows helps us understand the complex history of tropical biology. Their movement and evolution are tied to the geography of South America. The way they split into different groups tells a story about the land itself. By looking at both DNA and geological events, scientists can map the tree of life. This work connects the study of birds to the study of Earth's history. It shows how the environment shapes the creatures that live within it.

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🖼️ Images & Media (4)
File:Nothocrax urumutum -head -zoo-8a.jpg
Nothocrax urumutum -head -zoo-8a.jpg
File:Mitu tuberosa Whaldener Endo.jpg
Mitu tuberosa Whaldener Endo.jpg
File:Pauxi pauxi -Denver Zoo, Colorado, USA -head-8a.jpg
Pauxi pauxi -Denver Zoo, Colorado, USA...
File:Hocofaisán (8708251591).jpg
Hocofaisán (8708251591).jpg
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