Panamacebus transitus: First North American Monkey Fossils Unearthed in Panama
Seven fossil teeth recovered from the Miocene layers of the
Las Cascadas Formation in the Panama Canal Basin are the first evidence
of a monkey on the North American continent before the Isthmus of
Panama connected it to South America 3.5 million years ago, according to
a team of paleontologists led by Dr. Jonathan Bloch from the Florida
Museum of Natural History.
“The Miocene epoch (23.8–5.3 million years ago) is marked by
substantial climatic and ecological changes that had profound effects on
terrestrial mammal communities in the New World tropics,” Dr. Bloch and
his colleagues said.
“Fossils from the tropical lowlands of Central America are rare owing to a lack of relevant rock exposures; however, an important exception can be found in Panama where, since 2009, expansion of the Panama Canal has exposed fossil-bearing rocks of early Miocene age.”
The scientists found the 20.9 million-year-old teeth of a previously unknown monkey species in the Las Cascadas Formation during a five-year intensive fossil salvage project.
“Most of the mammal groups represented in the Las Cascadas Formation have North American origins, supporting the idea that Central America and western Panama represented a long peninsula extending south from North America,” they said.
They named the newfound species Panamacebus transitus in honor of Panama and the monkey’s movement across the ancient seaway that divided North and South America.
“We suggest that Panamacebus transitus was related to the capuchin and squirrel monkeys that are found in Central and South America today,” Dr. Bloch said.
“Prior to this discovery, New World monkeys were thought to have evolved in isolation on South America, cut-off from North America by a wide seaway.”
Before the teeth of Panamacebus transitus were discovered,
the oldest evidence of movement of a mammal from South to North America
are 8.5 – 9 million-year-old fossil remains of giant sloths.
Dr. Bloch and co-authors suggest two explanations:
(i) that mammals from South America were more adapted to life in the South American derived forests still found in Panama and Costa Rica than to other forest types characteristic of Northern Central America;
(ii) or that the lack of exposed fossil deposits throughout Central America means that evidence of these dispersals has yet to be revealed.
Research describing the new species is published online in the journal Nature.
_____
Jonathan I. Bloch et al. First North American fossil monkey and early Miocene tropical biotic interchange. Nature, published online April 20, 2016; doi: 10.1038/nature17415
Fonte: http://www.sci-news.com/paleontology/panamacebus-transitus-first-north-american-monkey-fossils-panama-03802.html
Palaeogeographic reconstruction showing hypothetical dispersal route of Panamacebus transitus
in the early Miocene. Yellow and ochre colors indicate subaerial
environments, blue colors indicate marine environments (dark, coastal
and platform; light, abyssal). Criteria used to arrive at this
reconstruction include regional tectonic reconstructions, local and
regional palaeomagnetic data, and regional strain markers and piercing
points. Fm. – formation, Fms – formations. Image credit: Jonathan I.
Bloch et al.
“Fossils from the tropical lowlands of Central America are rare owing to a lack of relevant rock exposures; however, an important exception can be found in Panama where, since 2009, expansion of the Panama Canal has exposed fossil-bearing rocks of early Miocene age.”
The scientists found the 20.9 million-year-old teeth of a previously unknown monkey species in the Las Cascadas Formation during a five-year intensive fossil salvage project.
“Most of the mammal groups represented in the Las Cascadas Formation have North American origins, supporting the idea that Central America and western Panama represented a long peninsula extending south from North America,” they said.
They named the newfound species Panamacebus transitus in honor of Panama and the monkey’s movement across the ancient seaway that divided North and South America.
“We suggest that Panamacebus transitus was related to the capuchin and squirrel monkeys that are found in Central and South America today,” Dr. Bloch said.
“Prior to this discovery, New World monkeys were thought to have evolved in isolation on South America, cut-off from North America by a wide seaway.”
A white-headed capuchin (Cebus capucinus) in Costa Rica. Image credit: Geoff Gallice / CC BY 2.0.
Dr. Bloch and co-authors suggest two explanations:
(i) that mammals from South America were more adapted to life in the South American derived forests still found in Panama and Costa Rica than to other forest types characteristic of Northern Central America;
(ii) or that the lack of exposed fossil deposits throughout Central America means that evidence of these dispersals has yet to be revealed.
Research describing the new species is published online in the journal Nature.
_____
Jonathan I. Bloch et al. First North American fossil monkey and early Miocene tropical biotic interchange. Nature, published online April 20, 2016; doi: 10.1038/nature17415
Fonte: http://www.sci-news.com/paleontology/panamacebus-transitus-first-north-american-monkey-fossils-panama-03802.html
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