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menemukannya
Ancient crocodile competed with Titanoboa, world's largest snake, for
food, paleontologists discover
Date:
September
16, 2011
Source:
University of Florida
Summary:
Did an ancient crocodile relative give the world's
largest snake a run for its money? In a new study, researchers describe a new
20-foot extinct species discovered in the same Colombian coal mine with
Titanoboa, the world's largest snake. The findings help scientists better
understand the diversity of animals that occupied the oldest known rainforest
ecosystem, which had higher temperatures than today, and could be useful for
understanding the impacts of a warmer climate in the future.
..............................
Did an ancient crocodile relative give the world's largest
snake a run for its money?
In a new
study appearing Sept. 15 in the journal Palaeontology, University of
Florida researchers describe a new 20-foot extinct species discovered in the
same Colombian coal mine with Titanoboa, the world's largest snake. The
findings help scientists better understand the diversity of animals that
occupied the oldest known rainforest ecosystem, which had higher temperatures
than today, and could be useful for understanding the impacts of a warmer
climate in the future.
The
60-million-year-old freshwater relative to modern crocodiles is the first known
land animal from the Paleocene New World tropics specialized for eating fish,
meaning it competed with Titanoboa for food. But the giant snake could have
consumed its competition, too, researchers say.
"The
younger individuals were definitely not safe from Titanoboa, but the biggest of
these species would have been a bit much for the 42-foot snake to handle,"
said lead author Alex Hastings, a graduate student at the Florida Museum of
Natural History and UF's department of geological sciences.
The new
species is a dyrosaurid, commonly believed to be primarily ocean-dwelling,
coastal reptiles. The new adult specimens challenge previous theories the
animals only would have entered freshwater environments as babies before
returning to sea.
Fossils of a
partial skeleton of the species, Acherontisuchus guajiraensis, show dyrosaurids
were key players in northeastern Colombia and that diversity within the family
evolved with environmental changes, such as an asteroid impact or the
appearance of competitors from other groups, said Christopher Brochu, an
associate professor of vertebrate paleontology in the department of geoscience
at the University of Iowa, who was not involved in the study.
"We're
facing some serious ecological changes now," Brochu said. "A lot of
them have to do with climate and if we want to understand how living things are
going to respond to changes in climate, we need to understand how they
responded in the past. This really is a wonderful group for that because they
managed to survive some catastrophes, but they seemed not to survive others and
their diversity does seem to change along with these ecological signals."
The species
is the second ancient crocodyliform found in the Cerrejon mine of northern
Colombia, one of the world's largest open-pit coal mines. The excavations were
led by study co-authors Jonathan Bloch, Florida Museum associate curator of
vertebrate paleontology, and paleobotanist Carlos Jaramillo of the Smithsonian
Tropical Research Institute.
"This
one is related to a group that typically had these long snouts" Hastings
said. "It would have had a relatively similar diet to the other (coastal)
species, but surprisingly it lived in a more freshwater environment."
The genus is
named for the river Acheron from Greek mythology, "the river of woe,"
since the animal lived in a wide river that emptied into the Caribbean. Unlike
the first crocodile relative found in the area, which had a more generalized
diet, the snout of the new species was long, narrow and full of pointed teeth,
showing a specialization for hunting the lungfish and relatives of bonefish
that inhabited the water.
"The
general common wisdom was that ancestrally all crocodyliforms looked like a
modern alligator, that all of these strange forms descended from a more
generalized ancestor, but these guys are showing that sometimes one kind of
specialized animal evolved from a very different specialized animal, not a
generalized one," Brochu said. "It's really showing us a level of
complexity to the history that 10 years ago was not anticipated."
During the
Paleocene in South America, the environment was dominated by reptiles,
including giant snakes, turtles and crocodiles. The dyrosaurid family
originated in Africa about 75 million years ago, toward the end of the age of
dinosaurs, and arrived in South America by swimming across the Atlantic Ocean.
"The
same thing that snuffed out the dinosaurs killed off most of the crocodiles
alive at the time," Hastings said. "The dyrosaurids are one of the
few groups to survive the extinction and later become more successful."
Story
Source:
The above
story is based on materials provided by University of Florida. The original article was written
by Danielle Torrent. Note: Materials may be edited for content and length.
Journal
Reference:
- Alexander K. Hastings, Jonathan I. Bloch, Carlos A. Jaramillo. A New Longirostrine Dyrosaurid (Crocodylomorpha, Mesoeucrocodylia) from the Paleocene of North-Eastern Colombia: Biogeographic and Behavioural Implications for New-World Dyrosauridae. Palaeontology,, 2011; 54 (5): 1095-1116 DOI: 10.1111/j.1475-4983.2011.01092.x
