The biological term 'postorbital' refers to behind the?
Postorbital bar a stiffened lateral orbit, deformation would displace soft tissues, when contraction of the anterior temporalis muscle takes place, thus impeding eye movement. A complete postorbital bar has evolved at least eleven times as a convergent adaptation in nine mammalian orders. Postorbital bars are characteristic to the following clades: Postorbital bars have furthermore developed individually in the following taxa: The presence of a postorbital bar in the extinct Oviraptorosauria species "Avimimus portentosus" was one of several defining characteristics that suggested to paleontologists that the species was more morphologically different from avian species than previously thought, affecting interpretation of the rate of
Postorbital bar evolution from dinosaurs to birds. Postorbital bars are likely derived from well-developed postorbital processes, an intermediate condition where a small gap retains between the process and the zygomatic arch. Well-developed postorbital processes have evolved separately within the orders of the Dermoptera and Hyracoidae and the Chiropteran families of Emballonuridae and Pteropodidae and to varying degrees within many carnivorian taxa. Complete postorbital bars and well-developed postorbital processes, retaining gaps of mere centimetres, spanned by the postorbital ligament, occur as polymorphisms within a number of pteropodid and hyracoid taxa. Postorbital bar The postorbital bar (or postorbital bone) is a bony arched structure