June 19, 2024

Uncovering the Mystery of Hispaniola’s Lost Rodent Species

Human beings have occupied Hispaniola for approximately 6 thousand years, throughout which time the islands rodent variety diminished from 11 types to simply 1. By identifying precisely when these types last appear in the fossil record, authors of a new research study identify the historic events that resulted in their extinction. Credit: Florida Museum picture by Kristen Grace
The Caribbean island of Hispaniola utilized to host 11 various rodent types, today just one remains in the islands 2 nations of Haiti and the Dominican Republic. The reasons for the extinction of the other species are uncertain, as the timing of each disappearance is unknown, making it difficult to recognize the cause. Additionally, the staying species potential customers for survival doubt.
A recent research study provides brand-new insights into the history of rodent species on Hispaniola. Researchers from the Florida Museum of Natural History and the Museo Nacional de Historia Natural in the Dominican Republic performed carbon-dating on the fossils of six hutia types, which are related to capybaras and look like a mix of a squirrel and a beaver. They also studied thousands of bones previously gathered over 40 years and kept at the Florida Museum of Natural History, browsing for resemblances that might clarify the recent wave of rodent extinctions.
” These concealed gems are what made this study possible,” stated Lazaro Viñola Lopez, a doctoral trainee at the University of Florida and lead author on the study.

Despite the preponderance of material offered for study, radiocarbon dating on fossils gathered in the tropics can be challenging organization. The regions high humidity, moisture, and heat speed up the destruction of collagen in the fossils needed to date them, leaving scientists with open concerns about their antiquity.
” They mineralize and lose all natural material truly quickly, so there are constraints to what you can date,” Lopez said.
The fossils used for this study, nevertheless, were excavated from sinkholes and caves, where they were sheltered from severe conditions and safe from marauding scavengers. Sinkholes typically serve as traps for animals, which fall in and are not able to get away, while many of the bones found in caves were straight transported there by predators like the Hispaniolan huge barn owl (Tyto ostologa). These big predators declined alongside the hutias and may have given in to extinction when their food source disappeared.
Hutias and the biological neighborhoods they supported flourished on Hispaniola for almost 20 million years, and it was previously unclear when they began to disappear. Early theories hypothesized that the types went extinct due to rapid climate change at the end of the glacial epoch in the late Pleistocene more than 10,000 years earlier. More current theories presume that the arrival of Indigenous people in the Caribbean and the later arrival of Europeans might have played a stronger function.
Nevertheless, scientists have been not able to make a precise estimate as to when they went extinct without understanding a “last look date,” or the age of the youngest specimen to have been found.
Prior to this research study, researchers had only a handful of radiocarbon dates for hutia fossils on which to base their assumptions. Here, the authors include carbon dates for an additional 6 species, all of which endured the period of climate modification initially theorized to have actually done them in.
This straight implicates humans in their disappearance.
It is approximated that the very first humans showed up on Hispaniola someplace between 4,000– 6,000 years ago. This lines up with a handful of older extinctions from the six outdated types, consisting of Rhizoplagiodontia lemkei, which was determined to have actually passed away out less than 6,000 years ago.
Starting approximately 3,000 years back, another group of Indigenous people moved into the Caribbean from contemporary Venezuela. These early islanders hunted hutias and even established an inter-island exchange of the animals, however these practices appear to have been performed sustainably.
Rather, European colonization appears to have been the primary reason for hutia decrease. Radiocarbon dates suggest that seven types went extinct within the last 2,000 years. Of these, at least 3 coincided with the arrival of Europeans.
Lopez presumes that gradual environment destruction, increasing human population numbers, and the intro of invasive species eventually caused the death of hutias together with several other mammal and bird types.
” When Europeans pertained to the island they brought several animals with them, like cats, rats, and canines,” he said. “Is it possible that these species went extinct because of competition with these brand-new animals? Thats simply one of the questions we can ask now since of this research study.”
According to Lopez, the results function as a jumping-off point for many future research studies into Caribbean rodents.
“Right now, we just have nine brand-new biometric dates. With a more comprehensive chronology, we can start to theorize about the past relationships between these species and the human beings on the island.”
Referral: “Endemic rodents of Hispaniola: biogeography and extinction timing during the Holocene” by Lazaro Willian Viñola-López, Jonathan I. Bloch, Juan N. Almonte Milán and Michelle J. LeFebvre, 29 October 2022, Quaternary Science Reviews.DOI: 10.1016/ j.quascirev.2022.107828.
The research study was funded by the American Society of Mammalogists..

People have actually lived in Hispaniola for roughly six thousand years, during which time the islands rodent variety decreased from 11 types to simply 1. By identifying exactly when these types last appear in the fossil record, authors of a new research study pinpoint the historical occasions that led to their extinction. A recent research study provides new insights into the history of rodent types on Hispaniola. Early theories speculated that the species went extinct due to rapid environment modification at the end of the ice ages in the late Pleistocene more than 10,000 years earlier. Radiocarbon dates suggest that 7 species went extinct within the last 2,000 years.