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How were Hylonomus and Paleothyris similar to modern lizards?

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A painted turtle (Chrysemys picta) with a dark shell and red and yellow markings rests on a rock near water, surrounded by green aquatic plants. — reptile Painted turtle (*Chrysemys picta*).

Hylonomus and Paleothyris are described as small, lizardlike animals that lived during the Late Carboniferous Period. They are classified as Eureptilia (true reptiles) and are recognized as some of the earliest known reptiles.1

Their similarity to modern lizards is primarily based on their overall physical appearance, as they are frequently characterized in the fossil record as "lizardlike" in form. Beyond this general morphological resemblance, these early reptiles were small creatures that inhabited forested environments.1

It is important to note that while they share this superficial resemblance to modern lizards, they represent a very early stage in the evolution of reptiles, distinct from the later-evolving lineages that include modern squamates (the order containing lizards and snakes).1