American tanagers’ colours and songs, new study


This video is called Colombia Tanagers [various species].

From Wildlife Extra:

Study dispels Darwin’s theory to prove birds can have it all

Despite popular belief birds can have a brilliant plumage, a virtuosic singing chirp and an intricate dance routine say scientists.

The author of a new study, Nick Mason, from the the Cornell Lab of Ornithology in New York state, challenged the long-held notion, first proposed by Charles Darwin, that for a bird species to excel in one area it must give up its edge in another.

For example, male northern cardinals are a dazzling scarlet, but sing a fairly simple whistle, whereas the dull brown House Wren sings one of the most complicated songs in nature.

Mason and his colleagues tested the theory by examining a very large family of songbirds from Central and South America, the tanagers.

This group consists of 371 species and included some of the most spectacularly colourful birds in the world such as the paradise tanager as well as the more drab birds, such the black-bellied seedeater. The group also includes both accomplished and weak songsters alike.

“If there were going to be any group of birds at all that would show this trade-off, the tanagers would be a very good candidate, because there’s all this variation in song and plumage complexity,” Mason said.

“But when we dived into it and did some rigorous statistics, it turns out that there is no overall trend. Tanagers can be drab and plain-sounding, or colourful and musical, or or anything in between.”

It’s still possible that trade-offs take place at the level of genus, Mason said, or that they influence species relatively fleetingly as evolutionary pressures appear and disappear.

But as a broad effect on an entire family of birds, a voice–plumage trade off doesn’t seem to exist. One possibility is that the resources needed to develop fancy plumage are different from the ones required for complex songs, freeing tanagers to invest in both forms of showiness simultaneously.

New prehistoric crocodile discovered, named after Tolkien’s balrog


This video is called Lord of the Rings – Gandalf vs Balrog.

From Sci-News.com:

Anthracosuchus balrogus: Giant Prehistoric Crocodile Discovered

June 4, 2014

Paleontologists have discovered a new species of crocodile-like reptile that swam in the rivers of what is now Colombia during [the] Paleocene, about 60 million years ago.

The newly discovered prehistoric monster has been named Anthracosuchus balrogus.

The specific epithet, balrogus, derives from the Balrog, the name of a ferocious fictional creature that appeared in J.R.R. Tolkien’s novel ‘The Lord of the Rings’ and dwelled deep in the middle-Earth ‘Mines of Moria.’

Anthracosuchus balrogus belongs to Dyrosauridae, a family of now-extinct crocodyliforms that lived from Late Cretaceous to the Eocene.

Originating in Africa, these crocodile-like reptiles swam across the Atlantic Ocean to South America about 75 million year ago. The family somehow survived the extinction event that wiped out the dinosaurs and persisted to become a top predator.

Four specimens of Anthracosuchus balrogus were unearthed in the Cerrejon coal mine, northern Colombia.

“It quickly became clear that the four fossil specimens were unlike any dyrosaur species ever found,” said Dr Alex Hastings from Martin Luther Universität Halle-Wittenberg, who is the lead author of a paper published in the journal Historical Biology.

The crocodyliforms that lived in the Cerrejon ecosystem during the Paleocene, when temperatures were higher than today, thrived and grew to enormous sizes.

“This group offers clues as to how animals survive extinctions and other catastrophes. As we face climates that are warmer today, it is important to understand how animals responded in the past. This family of crocodyliforms in Cerrejon adapted and did very well despite incredible obstacles, which could speak to the ability of living crocodiles to adapt and overcome,” Dr Hastings said.

Anthracosuchus balrogus was about 5 meters long, weighed 410 kg, and had an unusually blunt snout for species in the dyrosaurids family.

“The species’ short snout paired with large jaw muscles typical of dyrosaurids, would give it an incredibly powerful bite,” Dr Hastings said.

It lived in freshwater rivers alongside the famous giant Titanoboa snake (measured up to 18 meters long), ate turtles and fish.

“We couldn’t believe it had such a boxy, short skull and that it was still a dyrosaur. It really busts the mold for these animals. It is such a completely different looking beast than we’ve seen for these crocodile-like animals,” said co-author Dr Jonathan Bloch of Florida Museum.

“The study of dyrosaurids in Cerrejon is providing a better understanding of the early history of crocodiles in the Neotropics,” concluded senior author Dr Carlos Jaramillo of the Smithsonian Tropical Research Institute.

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