Panamá Canal job created a window on prehistory

Excavations to widen the Panamá Canal have been a boon to researchers who have discovered much about the isthmus and, by extension, Costa Rica.

The latest revelation is that there were monkeys in North America 21 million years ago. The researchers located fossilized monkey teeth when they were revealed by canal construction.

The  Smithsonian Tropical Research Institute has been leading the research, as has been the Florida Museum of Natural History and the New Mexico Museum of Natural History and Science. They have been partners in the Panamá Partnership for International Research and Education.

Not every day do contractors dig deep into the earth and open up areas for researchers to explore. The findings in Panamá are relevant to Costa Rica and its natural history. In fact, researchers think that until 3.5 million or fewer years ago what today is Panamá was just a peninsula south of today’s Costa Rica.

The North American and South American continents only joined at that time.

Fossils uncovered so far also include those of bats, horses, squirrels, small camelids, crocodiles, turtles and ferocious bear dogs, according to information from the  Smithsonian Tropical Research Institute.

A staff scientist there, Carlos Jaramillo, led the team that announced the latest discovery.

The team named the new monkey species Panamacebus transitus in honor of Panamá and the monkey’s movement across the ancient seaway that divided North and South America.

Species migrations across the Isthmus of Panamá began about 20 million years ago, some six times earlier than commonly assumed, a study reported last year. That date dovetails with the estimated age of the monkey teeth.

Geological movements uplifted Panamá so that the land bridge between the two Americans formed. But for millions of years today’s high spots in Panama were islands.

“We suggest that Panamacebus was related to the capuchin and squirrel monkeys that are

found in Central and South America today,” said Jonathan Bloch, curator of vertebrate
paleontology at the Florida Museum of Natural History on the University of Florida campus and lead author on the study published in Nature this week. “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.” He was quoted in a news release.

Many of the fossils uncovered by the researchers have North American origins, they have reported.

In February 2012, the scientists announced the discovery of two new extinct camel species that they said shed new light on the history of the tropics.

In March 2013, the scientists reported the discovery of  remarkably well-preserved fossils of two crocodilians and a mammal previously unknown to science.

Before the monkey teeth were discovered, the oldest evidence of movement of a mammal from South to North America are 8.5 to 9 million-year-old fossil remains of giant sloths, the Smithsonian said.

The authors of the new report suggest two explanations, according to the news release:

* 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 or

* that the lack of exposed fossil deposits throughout Central America means that evidence of these dispersals has yet to be revealed.

The $5.6 billion new, wider third lane of the Panamá Canal will open for business June 26, the report noted.

Sketch of how ancient monkey appeared.

Sketch of how ancient monkey appeared.

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