Fossil find expands known range for extinct saber-toothed cat

Education
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Jay Hartzell President | University of Texas at Austin

Important scientific finds do not always come in the biggest, most publicized packages. Sometimes new discoveries are made from seemingly insignificant objects. Such is the case of a 6-centimeter-wide, nondescript mass of bone and teeth that helped a scientist at The University of Texas at Austin expand the geographic footprint of a large cat that roamed the Earth tens of thousands of years ago.

“You can’t even tell what it is, let alone which animal it came from,” said John Moretti, a doctoral student at the UT Jackson School of Geosciences who led the research. “It’s like a geode. It’s ugly on the outside, and the treasure is all inside.”

The research was published in the May issue of The Anatomical Record.

In the fossil specimen that is the subject of this research paper, two teeth are visible breaking out at the bottom: an incisor and the tip of a partially-erupted canine. The scale bar at the top right of the image is 1 centimeter. Credit: Sam Houston State University

The fossil appears as a lumpy, rounded rock with exposed teeth showing signs of wear after being submerged and tumbled along the floor of the Gulf of Mexico for thousands of years before washing up on a beach. However, when X-rayed at UT's Computed Tomography Lab, Moretti discovered more within: a hidden canine tooth yet to erupt from its jaw bone.

This discovery enabled Moretti to identify it as belonging to Homotherium, a genus of large cat that roamed much of Earth for millions of years. This specific cat was not fully grown when it died; thus its distinctive saber-like canine tooth had not settled into its permanent position. Nestled inside the jawbone, it was protected from environmental elements.

“Had that saber tooth been all the way erupted and fully in its adult form, and not some awkward teenage in-between stage, it would have just snapped right off,” Moretti said. “It wouldn’t have been there, and we wouldn’t have that to use as evidence.”

Homotherium spanned across habitats in Africa, Eurasia, and America. It was about jaguar-sized with an elongated face, lanky front legs, and sloping back ending in a bobtail. Their serrated canine teeth were covered by large gum flaps similar to domestic dogs today.

While their fossils have been found in several areas in Texas before now this fossil indicates for the first time that these big cats roamed what is now-submerged continental shelf connecting Texas and Florida. Scientists hypothesize this stretch served as Neotropical corridor where animals such as capybaras or giant armadillos used humid grassland strip moving from Mexico through Texas towards Florida.

According to Moretti discovering Homotherium along this corridor offers insight into Late Pleistocene ecology since big carnivores like these cats shaped broader animal communities by controlling prey populations influencing regional biodiversity.

The fossil specimen discovered over 60 years ago on McFaddin Beach south Beaumont by Russell Long professor Lamar University but donated U.S Rep Brian Babin former student Long’s worked dentist 38 years Babin noted his training paleontology dentistry helped recognize seemingly strange rock upper jaw bone teeth

Research part larger initiative McFaddin Beach fossils started 2018 William Godwin curator Sam Houston State University Natural Science Museum co-author study Co-authors include Deanna Flores Christopher J Bell Adam Hartstone-Rose Patrick J Lewis Research funded UT Sam Houston State University North Carolina State University