Inner ear morphology of Adalatherium hui (Mammalia, Gondwanatheria) from the Late Cretaceous of Madagascar

Abstract The inner ear of the two higher clades of modern cetaceans (Neoceti) is highly adapted for hearing infrasonic (mysticetes) or ultrasonic (odontocetes) frequencies. Within odontocetes, Platanistoidea comprises a single extant riverine representative, Platanista gangetica, and a diversity of mainly extinct marine species from the late Oligocene onward. Recent studies drawing on features including the disparate tympanoperiotic have not yet provided a consensus phylogenetic hypothesis for platanistoids. Further, cochlear morphology and evolutionary patterns have never been reported. Here, we describe for the first time the inner ear morphology of late Oligocene–early Miocene extinct marine platanistoids and their evolutionary patterns. We initially hypothesized that extinct marine platanistoids lacked a specialized inner ear like P. gangetica and thus, their morphology and inferred hearing abilities were more similar to those of pelagic odontocetes. Our results reveal there is no “typical” platanistoid cochlear type, as the group displays a disparate range of cochlear anatomies, but all are consistent with high-frequency hearing. Stem odontocete Prosqualodon australis and platanistoid Otekaikea huata present a tympanal recess in their cochlea, of yet uncertain function in the hearing mechanism in cetaceans. The more basal morphology of Aondelphis talen indicates it had lower high-frequency hearing than other platanistoids. Finally, Platanista has the most derived cochlear morphology, adding to evidence that it is an outlier within the group and consistent with a >9-Myr-long separation from its sister genus Zarhachis. The evolution of a singular sound production morphology within Platanistidae may have facilitated the survival of Platanista to the present day.

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The morphology of the inner ear of squamate reptiles and its bearing on the origin of snakes

Royal Society Open Science ◽

10.1098/rsos.170685 ◽

2017 ◽

Vol 4 (8) ◽

pp. 170685 ◽

Cited By ~ 11

Author(s):

Alessandro Palci ◽

Mark N. Hutchinson ◽

Michael W. Caldwell ◽

Michael S. Y. Lee

Keyword(s):

Geometric Morphometrics ◽

Inner Ear ◽

Phylogenetic Signal ◽

Three Dimensional ◽

Lizard Species ◽

Squamate Reptiles ◽

Strong Affinity ◽

Ear Morphology

The inner ear morphology of 80 snake and lizard species, representative of a range of ecologies, is here analysed and compared to that of the fossil stem snake Dinilysia patagonica , using three-dimensional geometric morphometrics. Inner ear morphology is linked to phylogeny (we find here a strong phylogenetic signal in the data that can complicate ecological correlations), but also correlated with ecology, with Dinilysia resembling certain semi-fossorial forms ( Xenopeltis and Cylindrophis ), consistent with previous reports. We here also find striking resemblances between Dinilysia and some semi-aquatic snakes, such as Myron (Caenophidia, Homalopsidae). Therefore, the inner ear morphology of Dinilysia is consistent with semi-aquatic as well as semi-fossorial habits: the most similar forms are either semi-fossorial burrowers with a strong affinity to water ( Xenopeltis and Cylindrophis ) or amphibious, intertidal forms which shelter in burrows ( Myron). Notably, Dinilysia does not cluster as closely with snakes with exclusively terrestrial or obligate burrowing habits (e.g. scolecophidians and uropeltids). Moreover, despite the above similarities, Dinilysia also occupies a totally unique morphospace, raising issues with linking it with any particular ecological category.

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The relationship of development of cochlear nerve and inner ear morphology in children with congenital sensorineural hearing loss using high resolution MRI

2015 8th International Congress on Image and Signal Processing (CISP) ◽

10.1109/cisp.2015.7407930 ◽

2015 ◽

Author(s):

Qiang Li ◽

Zhen Wang

Keyword(s):

Hearing Loss ◽

High Resolution ◽

Sensorineural Hearing Loss ◽

Inner Ear ◽

Cochlear Nerve ◽

Sensorineural Hearing ◽

Ear Morphology ◽

High Resolution Mri ◽

Relationship Of ◽

The Relationship

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Inner-Ear Morphology of the New Zealand Kiwi (Apteryx mantelli) Suggests High-Frequency Specialization

Journal of the Association for Research in Otolaryngology ◽

10.1007/s10162-012-0341-4 ◽

2012 ◽

Vol 13 (5) ◽

pp. 629-639 ◽

Cited By ~ 6

Author(s):

Jeremy R. Corfield ◽

M. Fabiana Kubke ◽

Stuart Parsons ◽

Christine Köppl

Keyword(s):

New Zealand ◽

Inner Ear ◽

High Frequency ◽

Ear Morphology

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Bilateral Deafness in a Maltese Terrier and a Great Pyrenean Puppy: Inner Ear Morphology

Journal of Comparative Pathology ◽

10.1053/jcpa.1999.0360 ◽

2000 ◽

Vol 122 (2-3) ◽

pp. 223-228 ◽

Cited By ~ 20

Author(s):

A.G. Coppens ◽

A. Résibois ◽

L. Poncelet

Keyword(s):

Inner Ear ◽

Ear Morphology ◽

Bilateral Deafness

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Arenysaurus ardevoli, first paleoneuroanatomical description of a European hadrosaurid

10.7287/peerj.preprints.590 ◽

2014 ◽

Author(s):

Penélope Cruzado-Caballero ◽

Josep Fortuny ◽

Sergio Llacer ◽

José Ignacio JI Canudo

Keyword(s):

North America ◽

Inner Ear ◽

Late Cretaceous ◽

Cerebral Hemisphere ◽

3D Model ◽

General Pattern ◽

Semicircular Canals ◽

Major Axis ◽

Ontogenetic Stage ◽

And Behavior

The neuroanatomy of hadrosaurid dinosaurs is well known from North America and Asia. In Europe only a few cranial remains have been recovered with the braincase. Arenysaurus is the first European endocast for which the paleoneuroanatomy has been studied. The resulting data have enabled us to draw ontogenetic, phylogenetic and functional inferences. Arenysaurus preserves the endocast and the inner ear. This cranial material was CT-scanned, and a 3D-model was generated. The endocast morphology supports a general pattern for hadrosaurids with some characters that distinguish to a subfamily level, such as a brain cavity anteroposteriorly shorter or the angle of the major axis of the cerebral hemisphere to the horizontal in lambeosaurines. Both characters are present in the endocast of Arenysaurus. Moreover, osteological features indicate an adult ontogenetic stage while some paleoneuroanatomical features are indicative of a subadult ontogenetic stage and even a juvenile ontogenetic stage. Finally, a comparison with other hadrosaurids reveals that the low values for the angle of the dural peak may be an autapomorphy exclusive to the Parasaurolophus genus. It is hypothesized that the presence of puzzling characters that suggest different ontogenetic stages for this specimen, may reflect some degree of dwarfism in Arenysaurus. Regarding the inner ear, its structure shows differences from the ornithopod clade with respect to the height of the semicircular canals. These differences could lead to a decrease in the compensatory movements of eyes and head, with important implications for the paleobiology and behavior of hadrosaurid taxa such as Edmontosaurus, Parasaurolophus and Arenysaurus. These differences in the vestibular system could be used as a phylogenetical signal. The endocranial morphology of European hadrosaurids sheds new light on the evolution of this group and may reflect the conditions in the archipelago where these animals lived during the Late Cretaceous.

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