EVERYDAY SCIENCE

Detailed explanation-1: -Anapsid reptiles are characterized by a primitive skull with no temporal openings. Turtles are the only living representatives of this clade and belong to one order variously referred to as Testudines, Testudinata, or Chelonia.

Detailed explanation-2: -An anapsid is an amniote whose skull lacks one or more skull openings (fenestra, or fossae) near the temples. Traditionally, the Anapsida are the most primitive subclass of amniotes, the ancestral stock from which Synapsida and Diapsida evolved, making anapsids paraphyletic.

Detailed explanation-3: -Anapsids have no openings, synapsids have one opening, and diapsids have two openings. Temporal fenestrae are post-orbital openings in the skull that allow muscles to expand and lengthen. Anapsids have no temporal fenestrae, synapsids have one, and diapsids have two.

Detailed explanation-4: -Diapsida is a diverse clade of reptiles. Modern diapsids include lizards, snakes, turtles, birds, and crocodylians; extinct diapsids include dinosaurs, pterosaurs, ichthyosaurs, and many other familiar taxa.

Detailed explanation-5: -The Reptiles (except turtles) Even the birds are considered diapsids (and hence reptiles), because they are descended from certain dinosaurs (which are also diapsids), and ancestrally have the paired skull openings along with other physical characteristics that unite them with diapsids.