The ectotympanic, or tympanicum, is a bony structure found in all mammals, located on the tympanic part of the temporal bone, which holds the tympanic membrane (eardrum) in place. In catarrhine primates (including humans), it takes a tube-shape.[1][2] Its position and attachment to the skull vary between primates, and can be either inside or outside the auditory bulla.[3][4]
It is homologous with the angular bone of non-mammalian tetrapods.
^Fricano, Ellen Elise Irwin (2018). "The Primate Ectotympanic Tube: Correlates of Structure, Function, and Development". {{cite journal}}: Cite journal requires |journal= (help)
^Ankel-Simons, F. (2007). Primate Anatomy (3rd ed.). Academic Press. pp. 435–436. ISBN 0-12-372576-3.
^Archibald, J.D. (1977). "Ectotympanic bone and internal carotid circulation of eutherians in reference to anthropoid origins". Journal of Human Evolution. 6 (7): 609–622. doi:10.1016/S0047-2484(77)80134-6.
^Sellers, W.I. "Strepsirhine/Haplorhine Split" (PDF). Retrieved 18 August 2010.[permanent dead link]
The ectotympanic, or tympanicum, is a bony structure found in all mammals, located on the tympanic part of the temporal bone, which holds the tympanic...
preserves an ectotympanic bone of the middle ear, a delicate bone which is rarely preserved in Mesozoic mammal fossils. The ectotympanic is horseshoe-shaped...
advanced frontal sinus found in living catarrhines. However, it had a bony ectotympanic and teeth comparable to those of living catarrhines. Its discovery provided...
catarrhines, they face downward. Other distinctions include both a tubular ectotympanic (ear bone), and eight, not twelve, premolars in catarrhines, giving them...
large cavity in the ectotympanic, which holds the eardrum in place. The pacarana has several small cavities (sinuses) in the ectotympanic, so it may be that...
only in cetaceans (namely, the large auditory bulla is formed from the ectotympanic bone only). It was recognized as the earliest member of the family Pakicetidae...
elongate ectotympanics. The ectotympanics of all archaeocetes, nonetheless, are much different than those of terrestrial mammals. The ectotympanics of all...
prehensile tails, and have flat fingernails and toenails, a tubular ectotympanic (ear bone), and eight, not 12, premolars, giving them a dental formula...
recognised the ear structure of the auditory bulla, formed from the ectotympanic bone in a shape which is highly distinctive, found only in the skulls...
vibrations developed on the angular. Eventually, it developed into the ectotympanic ring which supports the tympanic membrane in the ears of modern mammals...
dental: (1) auditory bulla inflated and formed by the petrosal bone, (2) ectotympanic expanded laterally and fused medially to the wall of the bulla, (3) promontorium...
and held by another bone detached from the dentary, the tympanic plus ectotympanic), and coil their lagena (cochlea) to advance their hearing, with therians...
completely ossified ectotympanic tube. Epipliopithecus possesses an intermediate morphology in the form of a partially ossified ectotympanic tube. Some authors...
distinguishable, due to its position), or "intrabullar" (within the bullae), ectotympanic bone, connected to the lateral wall of the auditory bulla by an unbroken...
structure of the auditory bulla (ear bone), which is formed only from the ectotympanic bone. The shape of the ear region in pakicetids is highly unusual and...
fenestra (an opening on the top of the skull), there is a drop-like ectotympanic (a bony ring that holds the ear drum), and the bones are pachyosteosclerotic...
would be similar to that of extant apes and cercopithecoid monkeys. The ectotympanic tube was well-developed. This species lacked a tail and the canines of...
cavity, which surrounds the middle ear, is expanded. This leaves the ectotympanic ring, which supports the eardrum, free within the auditory bulla. This...
The devil, unlike other marsupials, has a "well-defined, saddle-shaped ectotympanic". Since devils hunt at night, their vision seems to be strongest in black...
to petrosal or lost mastoid foramen lost bulla if present composed of ectotympanic relatively bunodont teeth with low cusp relief trigonids of lower molars...
is distinct from other notharctine taxa in having a partially fused ectotympanic anulus in the auditory bulla, no stapedial artery, and no lower molar...
few other early eutherians retain a meckelian sulcus, a groove on the ectotympanic which hinted that a meckelian cartilage was present at the base of Eutheria...
includes a fragmentary rostrum, an endocast (interior of cranium), and an ectotympanic (ear bone). The specimen also had preserved cheek teeth, P3-M3, which...
tubular, accessory cusps absent on M3, a broad connection between the ectotympanic bulla and the falciform process of the squamosal, axis vertebra with...
auditory ossicles); they include the incus (quadrate), malleus (articular), ectotympanic (angular) and prearticular. In Mesozoic mammals these bones gradually...
platyrrhines, which do not have an ossified ectotympanic tube, and catarrhines, which have a completely ossified ectotympanic tube. Nearly all of what is known...
genus. Pelycodus is placed within adapiforms because of its annular ectotympanic, small eyes, non-elongated tarsus and numerous premolar and molar crests...
Meckels's cartilage, and the ectotympanic features an anterior limb and a straight reflected lamina. The anterior ectotympanic limb is nestled in a post-dentary...
modern anthropoids. The same specimen preserved a cross section of the ectotympanic ring, showing it to be an annular structure which was fused to the margin...
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