Rare Snake Fossils: Oligocene Quartet Discovered in Wyoming Sheds Light on Boa Evolution

A groundbreaking discovery in West Wyoming has revealed four remarkably intact snake fossils dating back approximately 38 million years. Paleontologists unearthed the quartet, complete with skulls, ribs, and tails in near-perfect condition, from Oligocene-era sediments. This find offers unprecedented insights into snake evolution and behavior during a period when North America experienced significant cooling. According to a 2023 study published in *Scientific Reports*, fossil discoveries like this are crucial for understanding the evolutionary history of reptiles and their adaptation to changing climates ^[1].

Unearthing the Oligocene Snake Fossil Quartet

Unlike typical snake fossil finds, which often consist of scattered vertebrae and bone fragments, these specimens are exceptionally complete. The snakes were preserved within a thin layer of fine mudstone, suggesting they perished within hours of each othre.Initial analysis links the fossils to known genera, but unique features quickly indicated the discovery of a new species, reshaping our understanding of the snake family tree.

Did You Know? the Oligocene epoch, spanning from about 34 to 23 million years ago, was a period of significant global cooling and major evolutionary changes in many plant and animal groups.

Hibernophis Breithaupti: A New Species Emerges

Detailed comparisons revealed distinct differences in jaw structure,tooth arrangement,and vertebrae compared to similar species like Ogmophis and Calamagras. These consistent differences across all four individuals led researchers to classify them as a new species: *Hibernophis Breithaupti*. The name honors the late Dr. Brent Breithaupt, a renowned paleontologist.

These small, burrowing snakes varied in size, with the largest specimen twice the length of its smaller counterparts. This size range provides a rare glimpse into the different life stages of a single species. According to the University of Alberta, the condition of the fossils is remarkable, as articulated snake skeletons are exceedingly rare ^[2].

DNA Analysis Reveals Evolutionary Relationships

The research team combined anatomical data with DNA sequences from modern snakes to determine evolutionary relationships. Their analysis places *Hibernophis* close to modern boa snakes, suggesting that the boa family diversified into multiple lineages during the early Oligocene.This discovery challenges previous assumptions about the timeline of boa evolution.

Pro Tip: When studying fossils, comparing anatomical data with genetic information from living relatives provides a more complete picture of evolutionary history.

Communal Hibernation: Evidence of Social Behavior

The arrangement of the four snake fossils suggests they were clustered together in a hibernaculum, a shared winter shelter. This indicates social behavior, a trait rarely observed in reptiles. Modern garter snakes exhibit similar behavior, gathering in large groups for warmth during winter. The Wyoming discovery suggests that communal sheltering may have been more widespread among ancient snakes than previously thought.

“This is truly unusual for reptiles. Of the nearly 15 thousand species of reptile species that live today, no one has a lot of people like garter snakes,” Caldwell said.

Volcanic Ash: The Key to Preservation

The exceptional preservation of the snake fossils is attributed to a nearby volcanic eruption. ash clouds settled on the floodplain, creating an airtight layer that slowed decay. This layer, alternating with mudflows from seasonal rains, encased the skeletons within the White River Formation, a fossil-rich geological unit spanning several Great Plains states.

small floods immediately clog the burrow with mud, so that the snakes are not disturbed until the miners split the stone. “Fosilization is a rough process that requires the right condition for preservation,” explained Caldwell.

How might this discovery change our understanding of ancient ecosystems? What other secrets might be hidden within the White River Formation?

Disclaimer: This article provides information about a paleontological discovery and is intended for educational purposes only. It does not provide any medical, financial, or legal advice.

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