Najash rionegrina (Apesteguía and Zaher 2006; Garberoglio FF et al. 2019; Late Cretaceous) is a tiny burrowing snake that retained a pelvis and hind limbs, transitional between Tetrapodophis and Loxocemus. The premaxilla was tiny, as in typical snakes. The mandible rose anteriorly, as in burrowing snakes. The jugal was retained.

Loxocemus bicolor (Cope 1862, 1.5m, extant) is a primitive snake close to the split between terrestrial and burrowing snakes. It lives both above and below ground.

Apesteguía S and Zaher H 2006. A Cretaceous terrestrial snake with robust hindlimbs and a sacrum. Nature. 440 (7087): 1037–1040.

Cope ED 1862. Some remarks defining the following species of Reptilia Squamata. Proceedings of the Academy of Natural Science. Philadelphia 1861:75-77.

Garberoglio FF et al. 2019. A new specimen with skull and vertebrae of Najash rionegrina (Lepidosauria: Ophidia) from the early Late Cretaceous of Patagonia. Journal of Systematic Palaeontology. 17 (18): 1313–1330.

wiki/Loxocemus
wiki/Najash