Rhynchocephalia

Rhynchocephalia is an order of reptiles that first appeared in the Triassic Period, approximately 250 million years ago. This ancient lineage diverged from lizards and snakes, and today, only one species, the tuatara (Sphenodon punctatus), survives. Tuatara are found exclusively in New Zealand and are often described as lizard-like reptiles.1

Key characteristics of Rhynchocephalia include biconcave vertebrae and unique skull structures. The tuatara, the sole living representative of this order, possesses a distinctive beak-like snout formed by fused premaxillary bones. These reptiles are largely nocturnal and have a slow metabolism, allowing them to remain active at lower body temperatures than many other reptiles. Their lineage is distinct from modern lizards and snakes, making them a significant group for understanding reptilian evolution.213