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BIRDS OF PREHISTORY PART DOS
Quick, say ‘bird’. What’s the first thing that pops up
in your mind? A sparrow? Gull? Ostrich? These forms may seem familiar today;
we’ve all seen birds in the wild and in zoos, but before man there were much,
much stranger birds that lived.
The
Enantiornithes: Conquerors of the Mesozoic
One
of the most successful groups of birds that ever existed was the
enantiornithes, which colonized the world of the dinosaurs for sixty six
million years. If you’ve ever watched Walking
with Dinosaurs, then you’ve most likely seen enantiornithes; the birds
attacking the pterosaur (similar to hummingbirds and other birds which will
attack hawks if they stray too close to their nests) were enantiornithes known
as Iberomesornis. A small
(finch-sized) bird, Iberomesornis
inhabited what is now Spain nearly 125mya, living near rivers and deltas with
oddities such as the dinosaur Pelecanimimus,
which can be imagined as a flightless pelican, and the hump-backed Concavenator, a carnivore related to Allosaurus. Known as the “opposite
birds”, due to the arrangement of the scapula/coracoid bones filled the niches
that are inhabited by passerines, sapsuckers and raptors today. We’ve already
talked about one in the first part of BOP, known as Avisaurus, which was like a red-tailed hawk with a meter-wide
wingspan and teeth. A Chinese form, Longipteryx,
would have filled the niche the kingfishers occupy today. However, all good
things must come to an end, and even though the enantiornithes stormed through
five of the world’s continents, they went extinct along with non-avian
dinosaurs 65mya.
Killer
Ducks and Seriemas: Birds Hold Their Grip
The
Cenozoic, the age we live in now, is often called the Age of the Mammals, due
to the fact mammals were evolving more rapidly and taking over niches the
non-avian dinosaurs left. Rhino-like uintatheres and brontotheres filled the
niche that non-avian dinosaurs like Triceratops
left behind; the cougar-like Patriofelis was
the apex mammalian predator. But dinosaurs, in the form of birds, weren’t
giving up just yet. For 16 million years, a 5-7ft tall bird terrorized North
America and Europe. Known as Gastornis,
this bird wasn’t large enough to take on the uintatheres that inhabited the
land at the time, but they were large enough to kill just about anything else
in their environments; pygmy horses in North America, anteater cousins in
Europe, etc. They faced little competition from mammals, except for the
aforementioned Patriofelis and the
jackal-sized Arctocyon. And while Gastornis, an anseriforme, died out 40
million years ago and mammals took over, South America wasn’t ready for
mammals’ rule yet.
They
came in the form of terror birds. When we went to the Field Museum, a model of
one, Andalgalornis, was in the room
where we saw the hawk. Terror birds reigned over South America for sixty million years, their rule ending
just 2 million years ago. Related to seriemas (cariamas), they were apex
predators, most of them nimble and agile, striking down prey with their sharp
talons and beaks. Phorusrhacos, a Gastornis-sized terror bird, was
anachronistically featured alongside sabertooth cats in Walking with Beasts. The largest terror birds were Titanis and Kelenken, 8ft and 10ft tall, respectively. The former actually
reached North America and managed to cause terror (no pun intended) for another
three million years, running alongside prey at speeds of 65 kph, rivaling that
of the ostrich. And then, for unknown reasons (probably niche competition),
they all died out, and were replaced by carnivores such as wolves and
sabertooth cats.
Pseudodontorns:
Pterosaurs Rise Again
Seventy-five
million years ago, a large pterosaur known as Pteranodon, soared over Kansas, when it was an interior sea, and
dwelled on cliffs, consuming fish. Fifty-five million years later, a similar
scene is repeated and the actors are birds. Known as the pseudodontorns, these
birds are known in the fossil record from 58-2mya, with the most famous being Osteodontornis, which lived 20mya in
North America. This bird had the second-largest wingspan in avian history,
surpassed only by a giant South American vulture (bonus points if you know its
name). The pseudodontorns were odd birds, with the largest possessing wingspans
of twenty feet. They also had bills lined with false teeth (hence, their group
name means ‘false tooth birds’), similar to the projections on mergansers’
bills. These giant birds would have filled the niche that some pterosaurs held
in the Mesozoic era, and the niche albatrosses fill now. When they went extinct
2.5mya, Olduvai stone tools were just being invented.
Samrukia and Gargantuavis: Giant Birds of the Mesozoic
Everyone
knows the Mesozoic as the heyday of the non-avian dinosaurs. They reached
immense sizes, so big that no other animal could get bigger than a rat when
they were alive. But that view is inaccurate. In reality, mammals, birds, and
reptiles flourished into various niches and sizes. Badger-sized mammals fed on
baby dinosaurs, crocs the size of SUVs walked around on land and terrorized
life. And even the birds were getting huge. On the islands of Late Cretaceous
France, a bird as tall as man roamed. Possibly related to the patagopterids mentioned
in Part 1, it was an herbivore, somewhat like a moa, and its name was Gargantuavis. But this wasn’t the only
giant bird around, or so it is thought. Very recently discovered, the Kazakh Samrukia was a bird that must have stood
10ft tall. However, its classification is disputed at the moment. Since it is
only known from a jawbone, some say it could be a pterosaur and some say it
could be an oviraptorosaur dinosaur. Whatever the case is, it was gigantic, and
proves that dinosaurs weren’t the only big ones around.
Presbyornis: The Flamingo-duck
We end this article on a peculiar bird that appeared
just three million years after the non-avian dinosaurs were wiped out (and it
could have possibly lived alongside the last dinosaurs, if scant fossil remains
prove to be from it). Named Presbyornis,
it was an early anseriform, which most professional birders would recognize as
the order that includes ducks, geese, swans, screamers, and magpie geese. While
an individual could weigh in at goose-swan size (14-33lbs), Presbyornis was much more gracile, with
longer legs, standing around 3-5ft tall. In fact, it resembled a flamingo with
the head of a dabbling duck, feeding on small animals and water plants. Presbyornis proved to be a successful
design, living for seven million years before dying out. The author hopes you
learned some new bird material from this article.
If Samrukia was a bird or oviraptorosaur, then it does nothing to dispel the idea that "dinosaurs were the only big ones around". (But the pterosaur interpretation appears to be more likely at the moment to begin with.)
ReplyDeleteThat's true, guess I was thinking "non-avian dinosaur" (though if it was an oviraptorosaur it would be one of those) and didn't translate it to paper.
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