Final answer:
Turtles are members of the clade Testudines, characterized by their unique shells made up of a carapace and plastron, and have diverse anatomical features such as varying eye positions and neck retraction methods. They cannot breathe underwater and exhibit excellent night vision. Turtle species have a broad size range and do not show parental care after laying eggs.
Step-by-step explanation:
Turtles are fascinating reptiles known for their distinctive bony or cartilaginous shells, which are incorporated into their skeletal system. The dorsal part of the shell is called the carapace and integrates the backbone and ribs, while the ventral part is known as the plastron. These reptiles, which belong to the clade Testudines, have a variety of anatomical features that suit their environments. For example, aquatic turtles have eyes positioned closer to the top of their heads, which allows them to stay submerged and watch for predators or prey. Another interesting aspect is their ability to retract their necks in different ways, dividing them into groups like Cryptodira and Pleurodira.
While many turtles are aquatic, it's important to note they do not breathe underwater but can hold their breath for extended periods. They also have exceptional night vision due to a large number of light-sensing cells in their eyes, which affords them color vision. Turtles are also ectothermic and don't exhibit parental care post-hatching. Their size can vary greatly, from the tiny speckled padloper tortoise to the massive leatherback sea turtle.