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

2017 ◽  
Vol 4 (8) ◽  
pp. 170685 ◽  
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.

scholarly journals Palaeoecological inferences for the fossil Australian snakes Yurlunggur and Wonambi (Serpentes, Madtsoiidae)

2018 ◽  
Vol 5 (3) ◽  
pp. 172012 ◽  
Author(s):  
Alessandro Palci ◽  
Mark N. Hutchinson ◽  
Michael W. Caldwell ◽  
John D. Scanlon ◽  
Michael S. Y. Lee
Keyword(s):  
Geometric Morphometrics ◽  
Inner Ear ◽  
Fossil Record ◽  
Upper Cretaceous ◽  
Three Dimensional ◽  
Late Cenozoic ◽  
Ecological Preferences ◽  
Shed Light ◽  
Ecological Differences

Madtsoiids are among the most basal snakes, with a fossil record dating back to the Upper Cretaceous (Cenomanian). Most representatives went extinct by the end of the Eocene, but some survived in Australia until the Late Cenozoic. Yurlunggur and Wonambi are two of these late forms, and also the best-known madtsoiids to date. A better understanding of the anatomy and palaeoecology of these taxa may shed light on the evolution and extinction of this poorly known group of snakes and on early snake evolution in general. A digital endocast of the inner ear of Yurlunggur was compared to those of 81 species of snakes and lizards with known ecological preferences using three-dimensional geometric morphometrics. The inner ear of Yurlunggur most closely resembles both that of certain semiaquatic snakes and that of some semifossorial snakes. Other cranial and postcranial features of this snake support the semifossorial interpretation. While the digital endocast of the inner ear of Wonambi is too incomplete to be included in a geometric morphometrics study, its preserved morphology is very different from that of Yurlunggur and suggests a more generalist ecology. Osteology, palaeoclimatic data and the palaeobiogeographic distribution of these two snakes are all consistent with these inferred ecological differences.

scholarly journals Hearing from the ocean and into the river: the evolution of the inner ear of Platanistoidea (Cetacea: Odontoceti)

Paleobiology ◽  
2021 ◽  
pp. 1-21
Author(s):  
Mariana Viglino ◽  
Maximiliano Gaetán ◽  
Mónica R. Buono ◽  
R. Ewan Fordyce ◽  
Travis Park
Keyword(s):  
Inner Ear ◽  
High Frequency ◽  
Sound Production ◽  
Marine Species ◽  
Late Oligocene ◽  
Evolutionary Patterns ◽  
Ear Morphology ◽  
Cochlear Morphology ◽  
First Time ◽  
Hearing Abilities

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.

Three-dimensional confocal microscopy of the mammalian inner ear

2010 ◽  
Vol 8 (3) ◽  
pp. 120-128 ◽  
Author(s):  
Glen H. MacDonald ◽  
Edwin W Rubel
Keyword(s):  
Confocal Microscopy ◽  
Inner Ear ◽  
Three Dimensional

A newly discovered skull of the temnospondyl amphibian Dendrerpeton acadianum Owen

1987 ◽  
Vol 24 (4) ◽  
pp. 796-805 ◽  
Author(s):  
Stephen J. Godfrey ◽  
Anthony R. Fiorillo ◽  
Robert L. Carroll
Keyword(s):  
Inner Ear ◽  
Posterior Margin ◽  
Functional Relationship ◽  
Impedance Matching ◽  
Three Dimensional ◽  
Natural Position ◽  
Lower Jaw ◽  
New Information ◽  
Early Tetrapods ◽  
Supporting Element

A virtually complete three-dimensional skull of a subadult of the temnospondyl amphibian Dendrerpeton acadianum provides new information on the structure of the palate and lower jaw. The left stapes appears to lie in a natural position on the quadrate ramus of the pterygoid. The proportionately large otic ossicle probably precluded it from having acted as a transmitter of airborne vibrations from a tympanum to the inner ear. The use of the term "otic notch" should be restricted to amphibians or reptiles in which the embayment of the posterior margin of the cheek is accompanied by the presence of a slender rod-like stapes that could have functioned as part of an impedance matching system. In those species in which a notch is present but the stapes is a massive "supporting" element, the term "squamosal embayment" should be used, rather than "otic notch." The squamosal embayment in early tetrapods may have been inherited directly from their fish ancestors and had no functional relationship to hearing.

Three-Dimensional Laser Surface Imaging and Geometric Morphometrics Resolve Frontonasal Dysmorphology in Schizophrenia

2007 ◽  
Vol 61 (10) ◽  
pp. 1187-1194 ◽  
Author(s):  
Robin J. Hennessy ◽  
Patrizia A. Baldwin ◽  
David J. Browne ◽  
Anthony Kinsella ◽  
John L. Waddington
Keyword(s):  
Geometric Morphometrics ◽  
Three Dimensional ◽  
Laser Surface ◽  
Surface Imaging

PATTERNS AND PROCESSES IN MORPHOSPACE: GEOMETRIC MORPHOMETRICS OF THREE-DIMENSIONAL OBJECTS

2016 ◽  
Vol 22 ◽  
pp. 71-99 ◽  
Author(s):  
P. David Polly ◽  
Gary J. Motz
Keyword(s):  
Geometric Morphometrics ◽  
Three Dimensional ◽  
Shape Space ◽  
Multivariate Methods ◽  
Morphometric Data ◽  
Three Dimensional Objects ◽  
Mathematical Properties ◽  
Patterns And Processes ◽  
The Relationship ◽  
Shell Coiling

AbstractFocusing on geometric morphometrics (GMM), we review methods for acquiring morphometric data from 3-D objects (including fossils), algorithms for producing shape variables and morphospaces, the mathematical properties of shape space, especially how they relate to morphogenetic and evolutionary factors, and issues posed by working with fossil objects. We use the Raupian shell-coiling equations to illustrate the complexity of the relationship between such factors and GMM morphospaces. The complexity of these issues re-emphasize what are arguably the two most important recommendations for GMM studies: 1) always use multivariate methods and all of the morphospace axes in an analysis; and 2) always anticipate the possibility that the factors of interest can have complex, nonlinear relationships with shape.

scholarly journals Characterizing phenotypic divergence using three-dimensional geometric morphometrics in four populations of threespine stickleback (Gasterosteus aculeatus; Pisces: Gasterosteidae) in Katmai National Park and Preserve, Alaska

2016 ◽  
Vol 94 (7) ◽  
pp. 463-472 ◽  
Author(s):  
A.E. Pistore ◽  
T.N. Barry ◽  
E. Bowles ◽  
R. Sharma ◽  
S.L. Vanderzwan ◽  
...  
Keyword(s):  
Geometric Morphometrics ◽  
National Park ◽  
Gasterosteus Aculeatus ◽  
Three Dimensional ◽  
Covariance Structure ◽  
Threespine Stickleback ◽  
Evolutionary Change ◽  
Ecological Processes ◽  
Vertebrate Model ◽  
Katmai National Park

The threespine stickleback (Gasterosteus aculeatus L., 1758) is a vertebrate model for the study of the relationship between phenotype and environment in facilitating rapid evolutionary change. Using four populations from a system of lakes in Katmai National Park and Preserve, Alaska, and microcomputed tomography and three-dimensional geometric morphometrics, we test the hypothesis that stickleback populations inhabiting freshwater environments display cranial phenotypes that are intermediate between the putative ancestral form and the low-plated freshwater populations that demonstrate substantial divergence toward new phenotypic optima. We further test the hypothesis that phenotypic covariance structure is disrupted in the context of such putatively recent adaptive events. We report significant phenotypic differences among all four populations that includes a component of sexual dimorphism. Furthermore, we show evidence of disrupted phenotypic covariance structure among these populations. Taken together, these findings indicate the importance of phenotypic quantification as a key step in elucidating both the ecological processes responsible for rapid adaptive radiations and the role of developmental mechanisms in biasing evolutionary change.

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