Tetrapodophis amplectus (Martill, Tischlinger and Longrich 2015; BMMS BK 2-2; 16 cm long) is a tiny, presumeably Early Cretaceous, Crato Formation (110 mya), stem snake with four complete limbs. It nests at the base of all snakes, including Dinilysia, Pachyrhachis and Boa in the large reptile tree, more derived than Pontosaurus.

Tetrapodophis retained a postorbital, squamosal and lacrimal. A broken jugal was also found. Palatal fangs were present along with a deep coronoid process. The torso was longer than the tail. The vertebrae have double articulations. Only a single row of ventral scales was present, as in snakes. It was a carnivore with tiny bones preserved in its gut as a last meal.

Barlochersaurus winhtini (Daza et al. 2018; privately owned, 1.5 cm long) is a much smaller Early Cretaceous (110 mya), pre-snake with four complete limbs and more typical lizardy proportions, despite the small limbs. Originally considered a basal anguimorph, adding more candidate taxa nests this tiny pre-snake between Pontosaurus and Tetrapodophis, further emphasizing the role of phylogenetic miniaturization in the origin of snakes. The naris and orbit are large. The teeth are recurved. The mouth opened widely.

Daza JD, Bauer AM, Stanley EL, Bolet A, Dickson B and Losos JB 2018. A enigmatic miniaturized and attenuate whole lizard from the Mid-Cretaceous amber of Myanmar. Breviora 563: 18pp.

Martill DM, Tischlinger H and Longrich NR 2015. A four-legged snake from the Early Cretaceous of Gondwana. Science 349 (6246): 416-419. DOI: 10.1126/science.aaa9208

wiki/Tetrapodophis