Comparative review of the human bony labyrinth

Spoor, Fred; Zonneveld, Frans W.

doi:10.1002/(sici)1096-8644(1998)107:27+<211::aid-ajpa8>3.0.co;2-v

Cited by 186 publications

(172 citation statements)

References 83 publications

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“…The radius of curvature averaged across all three canals in the mouse was found to be 0.859 mm, comparable to the 0.94 mm reported by Jones and Spells (1963) for the jerboa mouse, a rodent in the related family Dipodidae. The radius of curvature of the anterior canals in both strains of mice was larger than the radii of the horizontal and posterior canals, a relationship that has been reported in other species including cat (Blanks et al 1972), guinea pig (Curthoys et al 1975), human (Blanks et al 1975aSpoor and Zonneveld 1998), rhesus and squirrel monkey (Blanks et al 1985), and bird (Landolt and Correia 1980;Dickman 1996;Dickman and Fang 1996). The mouse canals are close to planar, with a maximum angle of divergence from the canal plane ranging from 3.8-to 12.6-.…”

Section: Discussionsupporting

confidence: 63%

Planar Relationships of the Semicircular Canals in Two Strains of Mice

Calabrese

Hullar

2006

JARO

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The mouse is increasingly important as a subject of vestibular research. Although many studies have focused on the vestibular responses of mice to angular rotation, the geometry of their semicircular canals has not been described. High-voltage X-ray computed tomography was used to measure the anatomy of the semicircular canals of two strains of mice, C57Bl/6J and CBA/CaJ. The horizontal plane of a stereotaxic coordinate system was defined by the midpoints of the external auditory meati and the point where the incisors emerge from the maxilla. The centroids of the lumens of the bony canals were calculated, and planes that describe the canals were fit using a least-squares regression analysis to the resulting points. Vectors normal to each regressed plane were used to represent the corresponding canal's axis of rotation, and angles of these vectors relative to skull landmarks as well as to each other were calculated. The horizontal canal of the mouse was found to be angled anteriorly upward 17.8-for CBA/CaJ and 32.6-for C57Bl/6J from the reference horizontal plane. Angles between ipsilateral canals deviated up to 12.3-from orthogonal, and angles between contralateral synergistic canals (left anterior-right posterior, right anterior-left posterior, and horizontal-horizontal) deviated from parallel by up to 14.8-. The orientations of the canals within the head as well as the orientations of the canals relative to each other were significantly different between the two strains, suggesting that care must be taken in the design and interpretation of developmental and physiologic studies involving different mouse strains.

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Section: Discussionsupporting

confidence: 63%

Planar Relationships of the Semicircular Canals in Two Strains of Mice

Calabrese

Hullar

2006

JARO

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“…It was compared quantitatively on the basis of arc shape and size of the semicircular canals, using features known to distinguish hominids, hylobatids, and other catarrhines 25,26,43,44 . Data are provided in Supplementary Table 1.…”

Section: Semicircular Canals Of the Inner Earmentioning

confidence: 99%

“…In the case of extant hominoids, this concerned a model representing the mean shape and size of the sample. Data were also obtained for additional anthropoid species 43,44 , for use in the phylogenetic analyses. The mean radius of curvature of the semicircular canals was scaled against body mass (Extended Data comparisons, but in a few cases published species averages were used to include key taxa.…”

Section: Semicircular Canals Of the Inner Earmentioning

confidence: 99%

New infant cranium from the African Miocene sheds light on ape evolution

Nengo

Tafforeau

Gilbert

et al. 2017

Nature

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and dental development, it possesses no definitive hylobatid synapomorphies. The combined evidence suggests that nyanzapithecines were stem hominoids close to the origin of extant apes, and that hylobatid-like facial features evolved multiple times during catarrhine evolution.Hominoids underwent a major evolutionary radiation during the Miocene epoch, with over 40 widely recognized species in at least 30 genera 1 . Despite this multitude of taxa, only about one-third are known from any cranial remains, and no more than half a dozen preserve any significant portion beyond the face and palate 2 . Thus, much about hominoid cranial evolution remains poorly understood, especially with respect to the ancestral morphology that gave rise to the clade containing extant apes and humans. Importantly, the African fossil record lacks any reasonably complete hominoid crania between 17 and 7 million years (Myr) ago, and no cranial specimens are known at all from between 14 and 10 Myr (refs 3-6), greatly hampering the analysis of hominoid evolution. The KNM-NP 59050 cranium reported here was recovered from Napudet (South Turkana, Kenya) and dated to 13 Myr; it thus falls within this critical yet poorly represented period. The infant specimen is nearly complete, but is missing the deciduous dental crowns (Fig. 1a-d and Extended Data Fig. 1a-f). The unerupted adult dentition, brain endocast, and bony labyrinths were visualized using propagation phase-contrast X-ray synchrotron microtomography (PPC-SR-CT; Fig. 1e-h Locality and horizon. Napudet (2° 57′ N, 35° 52′ E), Turkana Basin, Kenya, Emunyan Beds, Brown Bedded Tuffs (Extended Data Fig. 2a).Geological age. 13 Myr. Diagnosis.A large species of Nyanzapithecus, with M 1 significantly larger than in N. pickfordi (P < 0.05), N. harrisoni (P < 0.01), and probably N. vancouveringorum ( Fig. 3a and Extended Data Table 1a; Cranial morphologyKNM-NP 59050 is a nearly complete but somewhat distorted cranium of an infant primate (Fig. 1). The cranium is slightly crushed bilaterally and the posterior portion of the basicranium is both broken and distorted. All the deciduous tooth crowns are broken off, but their roots are preserved. The permanent teeth are unerupted, with the right I 1 being visible in its crypt.The overall dimensions of KNM-NP 59050 are similar to those of Symphalangus crania of equivalent dental age, except for the maxillo-alveolar size, which is similar to Hoolock (Extended Data Table 1b). Relative to overall cranial size, the snout is small as in juvenile hylobatids, and smaller than in extant juvenile hominids . This difference between hylobatids and hominids persists into adulthood (Extended Data Fig. 4b, d), and assuming that N. alesi followed the same pattern, its snout would have been relatively small as an adult, unlike that of Afropithecus and Saadanius.The orbits appear large, but are well within the expected range for an extant juvenile hominoid of its size (Extended Data Fig. 4e). The orbits are slightly taller than wide, which may reflect the bilateral dist...

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“…Additionally, data for other well-documented mammals [8,27,[30][31][32][33] support the fact that SC variation in threetoed sloths is unusually high. Neither large variation in SC shape nor differences in the relative sizes of each SC, as found in three-toed sloths ( figures 1 and 4), have, to our knowledge, previously been documented (although sample sizes in previous studies rarely permit good characterization of intraspecific diversity).…”

Section: Europaea)mentioning

confidence: 93%

High morphological variation of vestibular system accompanies slow and infrequent locomotion in three-toed sloths

et al. 2012

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The semicircular canals (SCs), part of the vestibular apparatus of the inner ear, are directly involved in the detection of angular motion of the head for maintaining balance, and exhibit adaptive patterns for locomotor behaviour. Consequently, they are generally believed to show low levels of intraspecific morphological variation, but few studies have investigated this assumption. On the basis of high-resolution computed tomography, we present here, to our knowledge, the first comprehensive study of the pattern of variation of the inner ear with a focus on Xenarthra. Our study demonstrates that extant three-toed sloths show a high level of morphological variation of the bony labyrinth of the inner ear. Especially, the variation in shape, relative size and angles of their SCs greatly differ from those of other, faster-moving taxa within Xenarthra and Placentalia in general. The unique pattern of variation in three-toed sloths suggests that a release of selection and/or constraints on their organ of balance is associated with the observed wide range of phenotypes. This release is coincident with their slow and infrequent locomotion and may be related, among other possible factors, to a reduced functional demand for a precise sensitivity to movement.

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Comparative review of the human bony labyrinth

Cited by 186 publications

References 83 publications

Planar Relationships of the Semicircular Canals in Two Strains of Mice

Planar Relationships of the Semicircular Canals in Two Strains of Mice

New infant cranium from the African Miocene sheds light on ape evolution

High morphological variation of vestibular system accompanies slow and infrequent locomotion in three-toed sloths

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