Black Leaf Beetle with bright red elytra, 8 mm in length. Family Chrysomelidae. I have never seen this one before. This may be of the genus Isotes (https://www.naturalista.mx/taxa/253206-I...). This article shows a beetle with red elytra with black spots. In the photos above, you can see faint black markings in the same place as the black spots of the ones in the article. It may be a variant of the same species, specifically Isotes octosignata. However, based on the information given below by thaptor, it seems this is an unresolved species as yet.
Semi-rural residential area, San Cristobal de Las Casas, Chiapas, Mexico, 2,200 meters.