Which traits do tuatara share with squamates such as lizards and snakes?
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tuatara
The species is the sole living member of the reptile order Rhynchocephalia.
Although tuatara are often described as lizardlike, they belong to the order Rhynchocephalia and are only distantly related to squamates—the group that includes lizards and snakes. Despite this deep evolutionary divergence, tuatara and squamates share several specific biological traits:
- Cloacal structure: Both groups possess a transverse cloacal opening (the vent).1
- Dentition: In both, the teeth are attached superficially to the jawbones.1
- Tail anatomy: Both groups exhibit fracture planes in their tail vertebrae, which allow for tail loss.1
- Skin shedding: Both undergo ecdysis, the periodic molting of skin to facilitate growth.1
- Waste excretion: To conserve water, both tuatara and squamates excrete uric acid.1
While they share these characteristics, tuatara remain distinct from squamates due to unique features such as the presence of gastralia (abdominal ribs), enclosed temporal fossae in the skull, and a specialized beaklike extension of the premaxillary bones.1