Inspired by an early tale of Vucub Caquix from the Popul Vuh. The art style is primarily Mayan, but there's also some influence from the Olmec, the Incas, and pre-Aztec Mexico. Contrary to popular belief, these cultures mixed and borrowed elements from each other quite frequently.
There's a surprising amount of anatomical study in Mayan art. While there are certainly primitive elements (heads in profile only), there's a variety of stances (frontal and three-quarter) and most impressively a wide selection of hand poses -- many of which would feel at home in sophisticated feature animation.