Leptodeira frenata yucatanensis
Yucatán, Mexico. June 26, 2016.
This little viper mimic is certainly Leptodeira frenata, but the subspecific designation is a little shaky. Purportedly, L. f. yucatanensis features orange or brown saddles on a dark background, and there is no dark outline bordering the saddles. This snake was found on the road at night near Piste. See also the lifelist entry for Leptodeira frenata frenata.
My Flickr album for Yucatán 2016 is here.
HerpMapper records for this species are here.