Question

Mention the general characters of Rhynchocephalia.

Answer 1

The order of lizard-like reptiles is called Rhynchocephalia. This order includes only one living species that is tuatara. Tuatara is a lizard in body form.

Complete answer:
Characters of rhynchocephalia

The Rhynchocephalia is the sister group to the squamata that are lizards .
They derive the skin structure by shedding mechanisms.
There is presence of opening in the pelvis called thyroid fenestra.
Paired male hemipenes are rudimentary in male Tuatara which are organs that help in delivering the sperms to females.
Have specialized foot and ankle structure.
Enlarged palatine tooth row .
Teeth are fused to the crest of jaw bone with no sockets- Acrodont dentition.
Transverse cloacal opening.
Fracture planes in the tail vertebrae.
Tongue notched distally and used to capture prey.
Most of the Rhynchocephalians belong to the group Sphenodontia .The sphenodontia is characterized by hooked beak like structure which is formed by enlarged premaxillary teeth.
The unique feature of tuatara is the presence of the Third eye on the top of the head but it is not used for seeing.

Note: The tuatara were classified as lizards in 1831. According to the fossil records it is called a living fossil. The tuatara has a diapsid skull but lacks a complete lower temporal bar. The tuatara is more active during night. The only extant Rhynchocephalians are the tuataras which occur only in New Zealand.