Presently, there are only seven known species of sea turtles, including two in the Lepidochelys genus: the olive ridley and Kemp's ridley. Despite their prevalence in the Caribbean Sea and beyond, there remains a dearth of knowledge about their evolutionary history. Recent excavation on Panama's Caribbean coast, however, has unearthed a significant find – the oldest fossil evidence of these turtles.
This fossil discovery in the Chagres Formation reveals a turtle that thrived approximately 6 million years ago during the upper Miocene Epoch in Panama. This era saw a global shift toward cooler and drier conditions, with polar ice accumulation, dwindling sea levels, and reduced rainfall.
A dedicated team of paleontologists, led by Dr. Edwin Cadena from the Universidad del Rosario in Bogotá, Colombia, and a research associate at the Smithsonian Tropical Research Institute in Panama, meticulously examined these remains.
Beyond being the earliest record of Lepidochelys turtles, the researchers made a startling revelation within the fossilized bones – traces of DNA. They identified well-preserved bone cells (osteocytes) with structures akin to cell nuclei. Using a solution called DAPI, they confirmed the presence of genetic material, a rarity in the vertebrate fossil record, previously noted only in two dinosaur fossils, including the infamous Tyrannosaurus rex.
This discovery not only enriches our understanding of biodiversity during the emergence of the Isthmus of Panama, which separated the Caribbean from the Pacific and united North and South America, but also delves into the preservation of soft tissues and potentially original biological matter like proteins and DNA. This burgeoning field is known as Molecular Paleontology.
Carlos De Gracia, a co-author of the study and a doctoral fellow associated with STRI, emphasized the significance of the rescued Caribbean fossils from Panama. They are rewriting the annals of marine vertebrates in the Isthmus.
This groundbreaking research stems from a collaborative effort between the Smithsonian Tropical Research Institute and the Faculty of Natural Sciences at the Universidad del Rosario. It was published in the Journal of Vertebrate Paleontology.
Headquartered in Panama City, Panama, STRI, a branch of the Smithsonian Institution, contributes significantly to our comprehension of tropical biodiversity, its relevance to human well-being, and the education of students in tropical research. Additionally, it raises public awareness about the significance and splendor of tropical ecosystems.