The labyrinthine morphology of Pronycticebus gaudryi (Primates, Adapiformes)

Lebrun, Renaud; Guillaume, Marc; Couette, Sébastien; Tafforeau, Paul; Zollikofer, Christoph P. E.

doi:10.1007/s12549-012-0099-z

Cited by 14 publications

(11 citation statements)

References 44 publications

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“…For example, the cochlea completes at least one complete 360° turn in living therian mammals, but less in monotremes and more basal mammals [31], [35]–[36]. The bony labyrinth of Mesozoic therians exhibit ancestral morphologies, such as a fusion of the posterior and lateral semicircular canals to form a secondary common crus, which is lost in several clades within crown Theria [37]–[40]. Within Primates, dimensions of the semicircular canals and other labyrinthine elements reflect evolutionary and phylogenetic history [41]–[42], and further phylogenetic information can be found in the inner ear of squamate reptiles [43]–[47].…”

Section: Introductionmentioning

confidence: 99%

Comparative Anatomy of the Bony Labyrinth (Inner Ear) of Placental Mammals

2013

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BackgroundVariation is a naturally occurring phenomenon that is observable at all levels of morphology, from anatomical variations of DNA molecules to gross variations between whole organisms. The structure of the otic region is no exception. The present paper documents the broad morphological diversity exhibited by the inner ear region of placental mammals using digital endocasts constructed from high-resolution X-ray computed tomography (CT). Descriptions cover the major placental clades, and linear, angular, and volumetric dimensions are reported.Principal FindingsThe size of the labyrinth is correlated to the overall body mass of individuals, such that large bodied mammals have absolutely larger labyrinths. The ratio between the average arc radius of curvature of the three semicircular canals and body mass of aquatic species is substantially lower than the ratios of related terrestrial taxa, and the volume percentage of the vestibular apparatus of aquatic mammals tends to be less than that calculated for terrestrial species. Aspects of the bony labyrinth are phylogenetically informative, including vestibular reduction in Cetacea, a tall cochlear spiral in caviomorph rodents, a low position of the plane of the lateral semicircular canal compared to the posterior canal in Cetacea and Carnivora, and a low cochlear aspect ratio in Primatomorpha.SignificanceThe morphological descriptions that are presented add a broad baseline of anatomy of the inner ear across many placental mammal clades, for many of which the structure of the bony labyrinth is largely unknown. The data included here complement the growing body of literature on the physiological and phylogenetic significance of bony labyrinth structures in mammals, and they serve as a source of data for future studies on the evolution and function of the vertebrate ear.

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Section: Introductionmentioning

confidence: 99%

Comparative Anatomy of the Bony Labyrinth (Inner Ear) of Placental Mammals

2013

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“…The morphology of the labyrinth also depends on the brain size. In lemurs and lorises, the semicircular canal arc size increases with the brain mass (Malinzak, 2010), and the PSC is more inferiorly positioned in relation to the LSC (Lebrun et al 2012). This morphological variation of the labyrinth accompanying brain size, i.e.…”

Section: Cranial Integrationmentioning

confidence: 99%

“…This morphological variation of the labyrinth accompanying brain size, i.e. the ratio of the brain volume to the length of the cranial base, could be a consequence of the petrous pyramid orientation (Lebrun et al 2012). Indeed, labyrinth shape is correlated to pyramid orientation (Spoor & Zonneveld, 1998;Jeffery & Spoor, 2004), which in turn is correlated to the relative brain size (Spoor, 1997;Spoor & Zonneveld, 1998;Lieberman et al 2000).…”

Section: Cranial Integrationmentioning

confidence: 99%

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New data about semicircular canal morphology and locomotion in modern hominoids

et al. 2017

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The labyrinth has two functional parts: the cochlea for audition and the vestibular system for equilibrioception. In the latter, the semicircular ducts and the otolithic organs are sensitive to rotational and linear accelerations of the head, respectively. The labyrinthine morphology influences perception accuracy, hence the adaptation to a specific locomotor pattern. The aim of this study is to determine the relationship between locomotion and semicircular canal morphology using geometric morphometrics, and to explain these links with existing functional models. The influence of factors other than functional constraints on labyrinthine morphology is discussed. The left bony labyrinth of 65 specimens was extracted virtually. Five extant hominoid species with various locomotion modes were sampled. A set of 13 landmarks was placed on the semicircular canals. After a Procrustes fit, their coordinates were analyzed using a principal component analysis. It was found that labyrinthine morphology is significantly distinct between species. More specifically, the differences involve a posterolateral projection of the lateral semicircular canal and the rotation of this canal relative to the vertical canals. This rotation occurs in the sagittal plane, which is consistent with previous studies based on traditional morphometrics. Among extant hominoids, the shape of the canals potentially discriminates species based on posture. This result could be used to reconstruct the locomotor pattern of fossil hominoids.

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“…Using geometric morphometrics for understanding bony labyrinth shape variation is rare (Lebrun et al. , ; Boistel et al. ; Gunz et al.…”

Section: Introductionmentioning

confidence: 99%

Bony labyrinth shape variation in extant Carnivora: a case study of Musteloidea

et al. 2015

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The bony labyrinth provides a proxy for the morphology of the inner ear, a primary cognitive organ involved in hearing, body perception in space, and balance in vertebrates. Bony labyrinth shape variations often are attributed to phylogenetic and ecological factors. Here we use three-dimensional (3D) geometric morphometrics to examine the phylogenetic and ecological patterns of variation in the bony labyrinth morphology of the most species-rich and ecologically diversified traditionally recognized superfamily of Carnivora, the Musteloidea (e.g. weasels, otters, badgers, red panda, skunks, raccoons, coatis). We scanned the basicrania of specimens belonging to 31 species using high-resolution X-ray computed micro-tomography (μCT) to virtually reconstruct 3D models of the bony labyrinths. Labyrinth morphology is captured by a set of six fixed landmarks on the vestibular and cochlear systems, and 120 sliding semilandmarks, slid at the center of the semicircular canals and the cochlea. We found that the morphology of this sensory structure is not significantly influenced by bony labyrinth size, in comparisons across all musteloids or in any of the individual traditionally recognized families (Mephitidae, Procyonidae, Mustelidae). PCA (principal components analysis) of shape data revealed that bony labyrinth morphology is clearly distinguishable between musteloid families, and permutation tests of the Kmult statistic confirmed that the bony labyrinth shows a phylogenetic signal in musteloids and in most mustelids. Both the vestibular and cochlear regions display morphological differences among the musteloids sampled, associated with the size and curvature of the semicircular canals, angles between canals, presence or absence of a secondary common crus, degree of lateral compression of the vestibule, orientation of the cochlea relative to the semicircular canals, proportions of the cochlea, and degree of curvature of its turns. We detected a significant ecological signal in the bony labyrinth shape of musteloids, differentiating semi-aquatic taxa from non-aquatic ones (the taxa assigned to terrestrial, arboreal, semi-arboreal, and semi-fossorial categories), and a significant signal for mustelids, differentiating the bony labyrinths of terrestrial, semi-arboreal, arboreal, semi-fossorial and semi-aquatic species from each other. Otters and minks are distinguished from non-aquatic musteloids by an oval rather than circular anterior canal, sinuous rather than straight lateral canal, and acute rather than straight angle between the posterior and lateral semicircular canals - each of these morphological characters has been related previously to animal sensitivity for detecting head motion in space.

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The labyrinthine morphology of Pronycticebus gaudryi (Primates, Adapiformes)

Cited by 14 publications

References 44 publications

Comparative Anatomy of the Bony Labyrinth (Inner Ear) of Placental Mammals

Comparative Anatomy of the Bony Labyrinth (Inner Ear) of Placental Mammals

New data about semicircular canal morphology and locomotion in modern hominoids

Bony labyrinth shape variation in extant Carnivora: a case study of Musteloidea

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