Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
lepidosaurian
References
Images
Diagram illustrating the evolutionary stages of turtle shell development, showing skeletal outlines of Eunotosaurus, Pappochelys, Odontochelys, and Proganochelys with red highlighting the expanding shell area over time. Below, side-by-side illustrations compare the body structure and stride length of early reptiles with flexible spines and fast crawling to Eunotosaurus and later turtles with rigid spines and slower movement.
Britannica AI Icon

lepidosaurian

reptile subclass
Also known as: Lepidosauria
Written by
The Information Architects of Encyclopaedia Britannica

The Information Architects maintain a master list of the topics included in the corpus of  Encyclopædia Britannica, and create and manage the relationships between them.
The Information Architects of Encyclopaedia Britannica
Last updated

Quick Summary

Diagram illustrating the evolutionary stages of turtle shell development, showing skeletal outlines of Eunotosaurus, Pappochelys, Odontochelys, and Proganochelys with red highlighting the expanding shell area over time. Below, side-by-side illustrations compare the body structure and stride length of early reptiles with flexible spines and fast crawling to Eunotosaurus and later turtles with rigid spines and slower movement.
turtle shell evolution Broad-ribbed bony structures likely evolved to provide early turtles with more stability and leverage for fossorial locomotion (burrowing). As these structures evolved and the turtle's carapace emerged in later forms, the flexibility of the spine was reduced and crawling speed declined.

Lepidosauria is a subclass of reptiles that first appeared in the early Permian period. These reptiles are characterized by having two temporal openings in their skulls and scaly skin. This group includes modern-day lizards, snakes, and tuataras.1

The subclass Lepidosauria is part of the larger class Reptilia. Within Lepidosauria, there are two main orders: Rhynchocephalia (which includes the tuatara) and Squamata (which includes lizards, snakes, and amphisbaenians). Lepidosaurians typically have teeth attached to the jaws and a parietal eye, often referred to as a "third eye".2

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
3 Britannica Sources
  1. Lepidosauria
  2. reptile - Annotated classification
  3. Lepidosauria

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.