Dirt, Bones & Siobhán Cooke

About 1 million years ago, endemic monkeys used to live on islands of the Caribbean. What today is one of our getaway destinations -Dominican Republic and Haiti-, is also a project site for scientists who look for fossil remains, some of which lead to new territorial distributions of these species’ habitats and to the understanding of their ruling over the Hispaniola, the reason why they’ve gone extinct.

Back in 2008, Anthropologist and Evolution Expert Siobhán Cooke began hunting for fossilized remains in an underwater cave in the La Altagracia province, on the east side of Dominican Republic. Since then, her team has worked on the description of the only two endemic monkey species known to have live on the island so far.

Recently, they found a new bone in a 26-foot-deep dry cave in the province of Pedernales, on the southwestern side of the Dominican territory. The newly discovered 4.3-inch-long primate femur leads to a new breakthrough in Caribbean paleontology.

From left to right, the summer 2015 team: Juan Almonte (Natural History Museum Santo Domingo), Alexis Mychajliw (Stanford University), Laura Gibson (Stanford University), Siobhán Cooke (Johns Hopkins University), Caridad Nova (UASD), Gerson Feliz (Grupo Jaragua).
From left to right, the summer 2015 team: Juan Almonte (Natural History Museum Santo Domingo), Alexis Mychajliw (Stanford University), Laura Gibson (Stanford University), Siobhán Cooke (Johns Hopkins University), Caridad Nova (UASD), Gerson Feliz (Grupo Jaragua).

JDMC: What does it mean to have found new remains of a primate on Hispaniola island?

SC: Currently, primates are known from La Altagracia province and also from the Tiburon Peninsula of Haiti. No primates have been found before in Pedernales, which lets us know more about where they used to live on the island. Additionally, Hispaniola used to be two paleoislands: one to the north and one to the south. Pedernales sits right at the boundary between the two islands and so its very important for understanding how the different animals might have moved between the two different islands.

JDMC: Who are the scientists and specialist involved in this investigation?

  • Juan Almonte works at the Natural History Museum in Santo Domingo. He has been conducting paleontological research in the Pedernales region for over 10 years.
  • Alexis Mychajliw is a Ph.D. student at Stanford University in the Biology Department. She is studying extinction processes on Hispaniola. She uses ancient DNA, isotopic analysis as well as data on the living hutias and solenodons.
  • Gerson Feliz is a member of the conservation organization Grupo Jaragua and a caving specialist. He also knows a lot about the conservation of the remaining endemic animals of the Dominican Republic.
  • Alfred Rosenberger is an Anthropology and Archaeology professor at Brooklyn College, specialist in Evolutionary Biology on Nonhuman primates with a focus on South and Central American forms.
  • Melissa Tallman is an Evolutionary Locomotor specialist with a focus on three-dimensional geometric morphometrics diversity in primates.
  • And me, Siobhán Cooke. I will be starting a position at Johns Hopkins University this summer in the Center for Functional Anatomy and Evolution. I am a specialist in Neotropical primates with a particular focus on the extinct Caribbean forms.

JDMC: When was the last time a discovery like this took place on the island?

SC: We have been recovering fossils from the caves every summer, but it has been about 6 years since a new primate locality was discovered.

The skull of Antillothrix Bernensis. This specimen was found in Altagracia in 2009.
The skull of Antillothrix bernensis. This specimen was found in La Altagracia in 2009.

The Hispaniolan monkey Antillothrix bernensis was first described by Renato Rímoli in 1977, deepened by Helen Green, Robyn Pickering, Siobhán Cooke, Alfred Rosenberger and Melissa Tallman after the discovery of a tibia fossil in an underwater cave in Parque Nacional del Este in La Altagracia province, Dominican Republic. They determined that the primate was an arboreal species, that fed on fruits and leafs, and lived on the island at least a million years ago.

JDMC: What did the team work on related to this species at Parque Nacional del Este, La Altagracia, Dominican Republic?

SC: Robyn Pickering and Helen Green conducted Uranium series dating on speleothem (a type of rock that forms in a cave) that covered a primate tibia. They found that the rock around the tibia was about 1.3 million years old!

The Insulacebus toussaintiana is a less known species, discovered by Dan Cordier y Charles Woods and described by Cooke and other specialists in 2011 from cranial-dental remains found on Tiburon Peninsula in Haiti.

JDMC: What was this investigation about and who worked with you?

SC: The fossils of Insulacebus were in the collections of the Florida Museum of Natural History in Gainesville. They were originally found my Dan Cordier who was working with Charles Woods (a professor at UF Gainesville) in the 1980’s. The specimens had remained unstudied for a long time, until the fossils were given to me to work on for my Ph.D. dissertation. I was interested in understanding if the primate fossils from Haiti were a different species from those at the other end of Hispaniola (La Altagracia). Since the island was once broken up into two islands, it wasn’t unreasonable to think that there might have been more than one monkey there. I worked on the fossils along with my colleague Sam Turvey and my Ph.D. advisor Alfred Rosenberger.

JDMC: Is there a possibility that the recently found femur in Parque Nacional Jaragua is related to the remains found previously?

SC: It is possible, but it will require some more study and more fossils to know for sure!

 Parque Nacional Jaragua from the road.
Collected fossils of these monkeys are about a million years old. Cooke’s team considers the femur found in Pedernales is just a few thousand years old. Parque Nacional Jaragua from the road.

JDMC: Why look for fossil remaining in the province of Pedernales?

SC: Juan Almonte had been working in Pedernales for many years collecting fossils. I was interested in exploring the area, because it lies at the boundary between the former northern and southern paleoislands. Renato Rímoli introduced me to Juan, and we began to collaborate in 2013. Parque Nacional Jaragua is a good place to look for fossils because there are many caves. Thousands of years ago, native animal fell into the cave and became trapped and today we are still able to find their fossils there.

JDMC: How do these discoveries change our understanding of life in the Caribbean?

SC: The endemic animals of Hispaniola and the Caribbean more generally suffered a major extinction event during the last 5,000 years or so. There used to be many rodents (Hutias), giant sloths (as big as a large dog), monkeys, and several different types of large shrews (Solenodon and Nesophontes). Nearly 85% of these animals did not survive and so we can only know about them through paleontology. By learning more about these animals we can learn more about the biological diversity in the Caribbean. It is also very important to understand why these animals went extinct so that we can save the few remaining animals that are still alive today.

Since 2013, the project has been carried out with funds donated by AAPA Professional Development Grant. It has been supported by Renato Rímoli and the staff of the Dominican Natural History Museum, the Museum of the Dominican Man and Grupo Jaragua.

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