Supratemporal bone

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The supratemporal bone is a paired cranial bone present in many tetrapods and tetrapodomorph fish.[1] It is part of the temporal region (the portion of the skull roof behind the eyes), usually lying medial (inwards) relative to the squamosal and lateral (outwards) relative to the parietal and/or postparietal. It may also contact the postorbital or intertemporal (which lie forwards), or tabular (which lies backwards), when those bones are present.[2]

The supratemporal is a common component of the skull in many extinct amphibians, though it is apparently absent in the lightweight skulls of living lissamphibians (frogs and salamanders). Embryological studies of salamanders suggests that the supratemporal fuses with the squamosal in early development.[3] A separate supratemporal was retained by early synapsids and reptiles, but was strongly reduced in many groups. Squamates (lizards and snakes) still possess a small supratemporal, though archosaurs (crocodilians and birds) and mammals lack it. Some extinct turtle relatives (like Proganochelys and Eunotosaurus) have a prominent supratemporal, but it is absent or fused to adjacent bones in modern turtles.[4][5]

References edit

  1. ^ Qiao, Tuo; Zhu, Min (2010). "Cranial morphology of the Silurian sarcopterygian Guiyu oneiros (Gnathostomata: Osteichthyes)". Science China Earth Sciences. 53 (12): 1836–1848. doi:10.1007/s11430-010-4089-6. ISSN 1674-7313. S2CID 54963054.
  2. ^ Parrington, F.R. (1937). "V.— A note on the supratemporal and tabular bones in reptiles". Annals and Magazine of Natural History. 20 (115): 69–76. doi:10.1080/00222933708655315. ISSN 0374-5481.
  3. ^ Schoch, Rainer R. (2014). "Amphibian skull evolution: The developmental and functional context of simplification, bone loss and heterotopy". Journal of Experimental Zoology Part B: Molecular and Developmental Evolution. 322 (8): 619–630. doi:10.1002/jez.b.22599.
  4. ^ Gaffney, Eugene S.; Meeker, Lorraine J. (1983-03-01). "Skull morphology of the oldest turtles: a preliminary description of Proganochelys quenstedti". Journal of Vertebrate Paleontology. 3 (1): 25–28. doi:10.1080/02724634.1983.10011953. ISSN 0272-4634.
  5. ^ Bever, G. S.; Lyson, Tyler R.; Field, Daniel J.; Bhullar, Bhart-Anjan S. (2015). "Evolutionary origin of the turtle skull". Nature. 525 (7568): 239–242. doi:10.1038/nature14900. ISSN 1476-4687. S2CID 4401555.