The inner ear morphology of the ‘condylarthran’<i>Hyopsodus lepidus</i>

Ravel, Anthony; Orliac, Maëva J.

doi:10.1080/08912963.2014.915823

Cited by 14 publications

(21 citation statements)

References 52 publications

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“… Data for comparative sample are from Cameron et al. (), Orliac & O'Leary (), Ravel & Orliac (), Muizon et al. (), Orliac & Gilissen () and Orliac et al.…”

Section: Methodsmentioning

confidence: 99%

“…Taxa illustrated are (A–D) Ch. pelvidens ( NMMNH P‐62258); (E–H) Diacodexis ilicis ( AMNHVP 16141; Orliac et al., 2012b); (I–L) Hyopsodus lepidus ( AMNHFM 143783; Ravel & Orliac, ); (M–P) Protungulatum sp. ( AMNHVP 118359; Orliac & O'Leary, ); (Q–T) Alcidedorbignya inopinata ( MHNC 8399; Muizon et al., ); (U–X) Carsioptychus coarctatus ( AMNH 27601; Cameron et al., ).…”

Section: Descriptions and Comparisonsmentioning

confidence: 99%

“…Neither feature could be identified in D. ilicis (AMNH VP 16141; Orliac et al., 2012a: fig. 2e) and H. lepidus (AMNH FM 143783; Ravel & Orliac, : fig. 2d); therefore, we annotated this region, the fenestra cochleae, for both specimens (Fig.…”

Section: Descriptions and Comparisonsmentioning

confidence: 99%

“…For morphological comparisons of the inner ear, we made comparisons to the Eocene artiodactyl Diacodexis ilicis (AMNH VP 16141; Orliac et al, 2012b), the potential Paleocene stem euungulate Protungulatum sp. (AMNH VP 118359; Orliac & O'Leary, 2016), two specimens of the Paleocene pantodont Alcidedorbignya inopinata (MHNC 8399;MHNC 8360;Muizon et al, 2015), the Paleocene periptychid 'condylarth' Carsioptychus coarctatus (AMNH 27601; Cameron et al, 2019), and the Eocene 'condylarth' Hyopsodus lepidus (AMNH FM 143783; Ravel & Orliac, 2015). For quantitative measurements, in addition to the specimens above, we made comparisons with Late Cretaceous eutherians: Ukhaatherium gobiensis (PSS-MAE 110; Ekdale, 2013), Kulbeckia kulbecke (average values), Zalambdalestes lechei (average values) and zhelestids (average values; Ekdale & Rowe, 2011).…”

Section: Comparative Samplementioning

confidence: 99%

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Virtual endocranial and inner ear endocasts of the Paleocene ‘condylarth’ Chriacus: new insight into the neurosensory system and evolution of early placental mammals

et al. 2019

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The end‐Cretaceous mass extinction allowed placental mammals to diversify ecologically and taxonomically as they filled ecological niches once occupied by non‐avian dinosaurs and more basal mammals. Little is known, however, about how the neurosensory systems of mammals changed after the extinction, and what role these systems played in mammalian diversification. We here use high‐resolution computed tomography (CT) scanning to describe the endocranial and inner ear endocasts of two species, Chriacus pelvidens and Chriacus baldwini, which belong to a cluster of ‘archaic’ placental mammals called ‘arctocyonid condylarths’ that thrived during the ca. 10 million years after the extinction (the Paleocene Epoch), but whose relationships to extant placentals are poorly understood. The endocasts provide new insight into the paleobiology of the long‐mysterious ‘arctocyonids’, and suggest that Chriacus was an animal with an encephalization quotient (EQ) range of 0.12–0.41, which probably relied more on its sense of smell than vision, because the olfactory bulbs are proportionally large but the neocortex and petrosal lobules are less developed. Agility scores, estimated from the dimensions of the semicircular canals of the inner ear, indicate that Chriacus was slow to moderately agile, and its hearing capabilities, estimated from cochlear dimensions, suggest similarities with the extant aardvark. Chriacus shares many brain features with other Paleocene mammals, such as a small lissencephalic brain, large olfactory bulbs and small petrosal lobules, which are likely plesiomorphic for Placentalia. The inner ear of Chriacus also shares derived characteristics of the elliptical and spherical recesses with extinct species that belong to Euungulata, the extant placental group that includes artiodactyls and perissodactyls. This lends key evidence to the hypothesized close relationship between Chriacus and the extant ungulate groups, and demonstrates that neurosensory features can provide important insight into both the paleobiology and relationships of early placental mammals.

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“… Data for comparative sample are from Cameron et al. (), Orliac & O'Leary (), Ravel & Orliac (), Muizon et al. (), Orliac & Gilissen () and Orliac et al.…”

Section: Methodsmentioning

confidence: 99%

Section: Descriptions and Comparisonsmentioning

confidence: 99%

Section: Descriptions and Comparisonsmentioning

confidence: 99%

Section: Comparative Samplementioning

confidence: 99%

See 2 more Smart Citations

Virtual endocranial and inner ear endocasts of the Paleocene ‘condylarth’ Chriacus: new insight into the neurosensory system and evolution of early placental mammals

et al. 2019

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“…In addition to 3D reconstruction, some of these available software packages offer the possibility to measure linear features, areas, and volumes as well (Ravel & Orliac, 2015). Commonly, data (e.g., volumes) are obtained in voxels (from the contraction of vox “volume” and el for “element”), which is a unit of graphic information that defines a point in three‐dimensional space, each coordinate being defined in terms of its position, color, and density (Higgins, Williams, Nagel, & Higgins, 2006).…”

Section: Processing Of X‐ray Ct Imagesmentioning

confidence: 99%

X‐ray computed tomography and its potential in ecological research: A review of studies and optimization of specimen preparation

Gutiérrez

Ott

Töpperwien

et al. 2018

Ecology and Evolution

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Imaging techniques are a cornerstone of contemporary biology. Over the last decades, advances in microscale imaging techniques have allowed fascinating new insights into cell and tissue morphology and internal anatomy of organisms across kingdoms. However, most studies so far provided snapshots of given reference taxa, describing organs and tissues under “idealized” conditions. Surprisingly, there is an almost complete lack of studies investigating how an organism′s internal morphology changes in response to environmental drivers. Consequently, ecology as a scientific discipline has so far almost neglected the possibilities arising from modern microscale imaging techniques. Here, we provide an overview of recent developments of X‐ray computed tomography as an affordable, simple method of high spatial resolution, allowing insights into three‐dimensional anatomy both in vivo and ex vivo. We review ecological studies using this technique to investigate the three‐dimensional internal structure of organisms. In addition, we provide practical comparisons between different preparation techniques for maximum contrast and tissue differentiation. In particular, we consider the novel modality of phase contrast by self‐interference of the X‐ray wave behind an object (i.e., phase contrast by free space propagation). Using the cricket Acheta domesticus (L.) as model organism, we found that the combination of FAE fixative and iodine staining provided the best results across different tissues. The drying technique also affected contrast and prevented artifacts in specific cases. Overall, we found that for the interests of ecological studies, X‐ray computed tomography is useful when the tissue or structure of interest has sufficient contrast that allows for an automatic or semiautomatic segmentation. In particular, we show that reconstruction schemes which exploit phase contrast can yield enhanced image quality. Combined with suitable specimen preparation and automated analysis, X‐ray CT can therefore become a promising quantitative 3D imaging technique to study organisms′ responses to environmental drivers, in both ecology and evolution.

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The Brain and Inner Ear of the Early Paleocene “Condylarth” Carsioptychus coarctatus: Implications for Early Placental Mammal Neurosensory Biology and Behavior

Cameron

Shelley

Williamson

et al. 2018

The Anatomical Record

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Mammals underwent a profound diversification after the end-Cretaceous mass extinction, with placentals rapidly expanding in body size and diversity to fill new niches vacated by dinosaurs. Little is known, however, about the brains and senses of these earliest placentals, and how neurosensory features may have promoted their survival and diversification. We here use computed tomography (CT) to describe the brain, inner ear, sinuses, and endocranial nerves and vessels of Carsioptychus coarctatus, a periptychid "condylarth" that was among the first placentals to blossom during the few million years after the extinction, in the Paleocene. Carsioptychus has a generally primitive brain and inner ear that is similar to the inferred ancestral eutherian/placental condition. Notable "primitive" features include the large, anteriorly expanded, and conjoined olfactory bulbs, proportionally small neocortex, lissencephalic cerebrum, and large hindbrain compared to the cerebrum. An encephalization quotient (EQ) cannot be confidently calculated because of specimen crushing but was likely very small, and comparisons with other extinct placentals reveal that many Paleocene "archaic" mammals had EQ values below the hallmark threshold of modern placentals but within the zone of nonmammalian cynodonts, indicative of small brains and low intelligence. Carsioptychus did, however, have a "conventional" hearing range for a placental, but was not particularly agile, with semicircular canal dimensions similar to modern pigs. This information fleshes out the biology of a keystone Paleocene "archaic" placental, but more comparative work is needed to test hypotheses of how neurosensory evolution was related to the placental radiation. Anat Rec, 302:306-324, 2019.

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The inner ear morphology of the ‘condylarthran’Hyopsodus lepidus

Cited by 14 publications

References 52 publications

Virtual endocranial and inner ear endocasts of the Paleocene ‘condylarth’ Chriacus: new insight into the neurosensory system and evolution of early placental mammals

Virtual endocranial and inner ear endocasts of the Paleocene ‘condylarth’ Chriacus: new insight into the neurosensory system and evolution of early placental mammals

X‐ray computed tomography and its potential in ecological research: A review of studies and optimization of specimen preparation

The Brain and Inner Ear of the Early Paleocene “Condylarth” Carsioptychus coarctatus: Implications for Early Placental Mammal Neurosensory Biology and Behavior

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