The Tehuantepec Isthmus Neotropical rattlesnake is a large-bodied species that was recently described in 2020. It resembles other species of the Neotropical rattlesnake complex; but is best distinguished by its range in Oaxaca and Chiapas where no similar species are found - though it may overlap with Crotalus simus in southern Chiapas and the Guatemalan border. Males have significantly longer tails than females.

The name "ehecatl" comes from the Nahuatl word “Ehēcatl” which means “the wind” or alternatively “Lord of the wind” from Aztec mythology. Ehēcatl is also interpreted as one of the manifestations of the feathered serpent, Quetzalcóatl.

This species inhabits tropical deciduous forests and seasonal rainforests along the Pacific versant of Mexico in Oaxaca and Chiapas, and may range as far south as Guatemala. It, like its sister species, prefers open canopy habitat with rocky outcroppings. It changes between crepuscular (morning & dusk) and nocturnal behavior in the warm months, with more diurnal activity in the cooler months.
Most feeding occurs during the rainy season.