Dr. Jesse Meik, assistant professor of biological sciences at Tarleton State University, has made a rare discovery of two species of rattlesnakes native to the Gulf of California.

Only about a half dozen new species of rattlesnakes, including the most recent two, have been discovered in the past century.

“Our findings are significant because most new rattlesnakes are simply elevated from subspecies to species status, but these two species were previously completely unknown to science,” Meik said.

The research has significant implications.

“Accurately describing and cataloging the world’s biodiversity is fundamental to our understanding of the history of life on Earth,” Meik explained. “In addition, different species of snakes show variations in venom properties, and those components have been used to synthesize new and powerful pharmaceuticals.”

For the past several years, Meik, a herpetologist, has led research expeditions to Gulf of California islands to study rattlesnakes. The research recently culminated in the discovery of the new speckled species, both of which are dwarfed, meaning they are much smaller in size than closely related species.

Meik and his team then used gene sequencing to determine that the rattlesnakes were indeed new species.

One of the species was named Crotalus polisi, after Gary Allan Polis, an arachnologist from the University of California-Davis who died at sea when a ship capsized in a storm returning from an expedition to Horsehead Island — the island inhabited by the new species.

The other species, endemic to Louse Island, is named Crotalus thalassoporus, derived from the Greek word for “sea traveller.” This species appears to have migrated over sea to a nearby island and the mainland where it bred with rattlesnakes.

Undergraduate student Caitlyn Pyle traveled with Meik on the most recent expedition, supported by Tarleton’s Undergraduate Research Assistant program.

Meik is sequencing the entire mitochondrial genomes of these new species and related snakes to examine unusual molecular evolutionary dynamics in island populations. Pending funding and renewed work permits in Mexico, plans are to study the life histories and diets of these snakes to better understand the ecological basis of insular dwarfism.

Meik’s discovery has been documented in the Journal of Natural History.