A group of fossil collectors has discovered a mass Ice Age fossil grave buried in Florida’s Steinhatchee River. More than 500 fossils have been unearthed at the site, with most of them dating back half a million years. The bones were well-preserved and came mostly from ancient mammals like horses, giant armadillos, sloths, and what could be a new tapir species.
The bones were first discovered in 2022 when two fossil collectors, Robert Sinbaldi and Joseph Branin, found them during a routine dive in the river. Mr. Branin spotted the first one, a horse tooth. The divers then discovered a hoof core and a tapir skull.
A sinkhole opened in the state’s Big Bend region 500,000 years ago, effectively becoming a mass grave for hundreds of animals caught in the wrong place at the wrong time. Over time, the Steinhatchee River flowed over the area, and sediment filled the sinkhole, preserving the remains of the prehistoric animals in excellent condition.
The Florida Museum dated the fossil grave to the Irvingtonian North American Land Mammal Age
Recognizing the significance of the site, particularly due to the condition of the fossils, the Florida Museum dated the finds to an evolutionary transition period (1.6 million–250,000 years ago). This discovery is crucial as it originates from a prehistoric period lacking fossils available for study.
Fossil collectors in Florida have discovered an ancient sinkhole, now at the bottom of a river, which holds the remains of animals rarely seen in the state, including a type of giant armadillo, giant ground sloths, and an odd-looking tapir.
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This was further explained by Rachel Narducci, who is the vertebrate paleontology collections manager at the Florida Museum and coauthor of a study of the site. In a statement, Ms. Narducci said, “The fossil record everywhere, not just in Florida, is lacking the interval that the site is from.” Her study was published last November in the academic journal, Fossil Studies.
One of the most intriguing fossils is that of an extinct pre-historic giant armadillo
The Holmesina was an armadillo-like creature that lived two million years ago. Scientists knew there was a transition within the species between two specimens, the H. floridanus, to H. septentrionalis, which reached a weight of 475 pounds. Until the discovery of the site, there was little evidence that could explain how the evolutionary change happened.
The study revealed that the fossils recovered from the site showed that the ankle and foot bones from the two specimens matched those of the Holmesina species. According to Narducci, the explanation is that “They got bigger before the shape of their bones changed.”
Another key finding of the site was that of what could be a new species of Tapir. Researchers studying the fossil believe this might be the case because the skull had features that were not seen in any previous fossil record. Another one of the study’s main authors, Richard Hulbert has not claimed it to be a new species just yet, as “We need more of the skeleton to firmly figure out what’s going on with this tapir,” adding that, “It might be a new species. Or it always could just be that you picked up the oddball individual of the population.”