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 extantarchosaurs, birds still possess antorbital fenestrae, whereas crocodylians have lost them. The loss in crocodylians is believed to be related to the structural needs of their skulls for the bite force and feeding behaviours that they employ.[1][2] In some archosaur species, the opening has closed but its location is still marked by a depression, or fossa, on the surface of the skull called the antorbital fossa.
The antorbital fenestra in relation to the other skull openings in the dinosaurMassospondylus.
The antorbital fenestra houses a paranasal sinus that is confluent with the adjacent nasal capsule.[3] Although crocodylians walled over their antorbital fenestra, they still retain an antorbital sinus.[3]
In theropoddinosaurs, the antorbital fenestra is the largest opening in the skull. Systematically, the presence of the antorbital fenestra is considered a synapomorphy that unites tetanurantheropods as a clade. In contrast, most ornithischian dinosaurs reduce and even close their antorbital fenestrae[3] such as in hadrosaurs and the dinosaur genus Protoceratops. This closure distinguishes Protoceratops from other ceratopsian dinosaurs.[4]
^ abcWitmer, L.M. 1997. The Evolution of the Antorbital Cavity of Archosaurs: A Study in Soft-Tissue Reconstruction in the Fossil Record with an Analysis of the Function of Pneumaticity. JVP 17(1 supp):1–76.
^Martin, A.J. (2006). Introduction to the Study of Dinosaurs. Second Edition. Oxford, Blackwell Publishing. pg. 299-300. ISBN1-4051-3413-5.
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Archosaur Morphology
May 04, 2024
antorbital, fenestra, antorbital, fenestra, plural, fenestrae, opening, skull, that, front, sockets, this, skull, character, largely, associated, with, archosauriforms, first, appearing, during, triassic, period, among, extant, archosaurs, birds, still, posses. 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 birds still possess antorbital fenestrae whereas crocodylians have lost them The loss in crocodylians is believed to be related to the structural needs of their skulls for the bite force and feeding behaviours that they employ 1 2 In some archosaur species the opening has closed but its location is still marked by a depression or fossa on the surface of the skull called the antorbital fossa The antorbital fenestra in relation to the other skull openings in the dinosaur Massospondylus The antorbital fenestra houses a paranasal sinus that is confluent with the adjacent nasal capsule 3 Although crocodylians walled over their antorbital fenestra they still retain an antorbital sinus 3 In theropod dinosaurs the antorbital fenestra is the largest opening in the skull Systematically the presence of the antorbital fenestra is considered a synapomorphy that unites tetanuran theropods as a clade In contrast most ornithischian dinosaurs reduce and even close their antorbital fenestrae 3 such as in hadrosaurs and the dinosaur genus Protoceratops This closure distinguishes Protoceratops from other ceratopsian dinosaurs 4 See also editFenestra anatomy References edit Preushscoft H Witzel U 2002 Biomechanical Investigations on the Skulls of Reptiles and Mammals Senckenbergiana Lethaea 82 207 222 Rayfield E J Milner A C Xuan V B Young P G 2007 Functional Morphology of Spinosaur Crocodile Mimic Dinosaurs JVP 27 4 892 901 a b c Witmer L M 1997 The Evolution of the Antorbital Cavity of Archosaurs A Study in Soft Tissue Reconstruction in the Fossil Record with an Analysis of the Function of Pneumaticity JVP 17 1 supp 1 76 Martin A J 2006 Introduction to the Study of Dinosaurs Second Edition Oxford Blackwell Publishing pg 299 300 ISBN 1 4051 3413 5 External links editArchosaur Morphology Retrieved from https en wikipedia org w index php title Antorbital fenestra amp oldid 1149338223, wikipedia, wiki, book, books, library,
