An infratemporal

fenestra A fenestra (fenestration; plural fenestrae or fenestrations) is any small opening or pore, commonly used as a term in the biological sciences. It is the Latin word for "window", and is used in various fields to describe a pore in an anatomical st ...

, also called the lateral temporal fenestra or simply temporal fenestra, is an opening in the skull behind the

orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...

in some animals. It is ventrally bordered by a zygomatic arch. An opening in front of the eye sockets, conversely, is called an

antorbital fenestra An antorbital fenestra (plural: fenestrae) is an opening in the skull that is in front of the eye sockets. This skull character is largely associated with archosauriforms, first appearing during the Triassic Period. Among extant archosaurs, bird ...

. Both of these openings reduce the weight of the skull. Infratemporal fenestrae are commonly (although not universally) seen in the fossilized skulls of

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s. Synapsids, including

mammals Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur o ...

, have one temporal fenestra, while sauropsids, the birds and reptiles, have two.

References

{{ref list Dinosaur anatomy Foramina of the skull