1
|
Jagielska N, O'Sullivan M, Butler IB, Challands TJ, Funston GF, Ross D, Penny A, Brusatte SL. Osteology and functional morphology of a transitional pterosaur Dearc sgiathanach from the Middle Jurassic (Bathonian) of Scotland. BMC Ecol Evol 2025; 25:9. [PMID: 39849380 PMCID: PMC11761736 DOI: 10.1186/s12862-024-02337-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2024] [Accepted: 12/04/2024] [Indexed: 01/25/2025] Open
Abstract
Pterosaurs were the first vertebrates to evolve active flight. The lack of many well-preserved pterosaur fossils limits our understanding of the functional anatomy and behavior of these flight pioneers, particularly from their early history (Triassic to Middle Jurassic). Here we describe in detail the osteology of an exceptionally preserved Middle Jurassic pterosaur, the holotype of Dearc sgiathanach from the Isle of Skye, Scotland. We identify new autapomorphies of the flight apparatus (humerus and sternum), which further support the distinctiveness of Dearc compared with other early-diverging pterosaurs and describe features, such as the vertebral morphology, shared with later-diverging pterosaurs that probably developed convergently to support a large body size or as a sign of modular evolution. We used extant phylogenetic bracketing to infer the principal cranial and antebrachial musculature, indicating that Dearc had large and anteriorly placed palatal musculature that compensated for weak temporal jaw adductors and wing musculature suggestive of flight style reliant on powerful adduction and protraction of the humerus. Comparisons with other pterosaurs revealed that non-pterodactyloids such as Dearc, despite their overall conservative bauplans, adapted various flight and feeding styles. The osteology and myology of Dearc are indicative of a large predator that flew and hunted above lagoons and nearshore environments of the Middle Jurassic.
Collapse
Affiliation(s)
- Natalia Jagielska
- School of GeoSciences, University of Edinburgh, Edinburgh, Scotland.
- Lyme Regis Philpot Museum, Lyme Regis, Dorset, England.
| | | | - Ian B Butler
- School of GeoSciences, University of Edinburgh, Edinburgh, Scotland
| | | | - Gregory F Funston
- Department of Earth and Planetary Sciences, University of California, Davis, Davis, CA, USA
| | | | - Amelia Penny
- School of GeoSciences, University of Edinburgh, Edinburgh, Scotland
| | | |
Collapse
|
2
|
Widrig KE, Navalón G, Field DJ. Paleoneurology of stem palaeognaths clarifies the plesiomorphic condition of the crown bird central nervous system. J Morphol 2024; 285:e21710. [PMID: 38760949 DOI: 10.1002/jmor.21710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 04/29/2024] [Accepted: 05/03/2024] [Indexed: 05/20/2024]
Abstract
Lithornithidae, an assemblage of volant Palaeogene fossil birds, provide our clearest insights into the early evolutionary history of Palaeognathae, the clade that today includes the flightless ratites and volant tinamous. The neotype specimen of Lithornis vulturinus, from the early Eocene (approximately 53 million years ago) of Europe, includes a partial neurocranium that has never been thoroughly investigated. Here, we describe these cranial remains including the nearly complete digital endocasts of the brain and bony labyrinth. The telencephalon of Lithornis is expanded and its optic lobes are ventrally shifted, as is typical for crown birds. The foramen magnum is positioned caudally, rather than flexed ventrally as in some crown birds, with the optic lobes, cerebellum, and foramen magnum shifted further ventrally. The overall brain shape is similar to that of tinamous, the only extant clade of flying palaeognaths, suggesting that several aspects of tinamou neuroanatomy may have been evolutionarily conserved since at least the early Cenozoic. The estimated ratio of the optic lobe's surface area relative to the total brain suggests a diurnal ecology. Lithornis may provide the clearest insights to date into the neuroanatomy of the ancestral crown bird, combining an ancestrally unflexed brain with a caudally oriented connection with the spinal cord, a moderately enlarged telencephalon, and ventrally shifted, enlarged optic lobes.
Collapse
Affiliation(s)
- Klara E Widrig
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - Guillermo Navalón
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
| | - Daniel J Field
- Department of Earth Sciences, University of Cambridge, Cambridge, UK
- Museum of Zoology, University of Cambridge, Cambridge, UK
- Fossil Reptiles, Amphibians and Birds Section, The Natural History Museum, London, UK
| |
Collapse
|
3
|
Barker CT, Naish D, Trend J, Michels LV, Witmer L, Ridgley R, Rankin K, Clarkin CE, Schneider P, Gostling NJ. Modified skulls but conservative brains? The palaeoneurology and endocranial anatomy of baryonychine dinosaurs (Theropoda: Spinosauridae). J Anat 2023; 242:1124-1145. [PMID: 36781174 PMCID: PMC10184548 DOI: 10.1111/joa.13837] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/17/2023] [Accepted: 01/17/2023] [Indexed: 02/15/2023] Open
Abstract
The digital reconstruction of neurocranial endocasts has elucidated the gross brain structure and potential ecological attributes of many fossil taxa, including Irritator, a spinosaurine spinosaurid from the "mid" Cretaceous (Aptian) of Brazil. With unexceptional hearing capabilities, this taxon was inferred to integrate rapid and controlled pitch-down movements of the head that perhaps aided in the predation of small and agile prey such as fish. However, the neuroanatomy of baryonychine spinosaurids remains to be described, and potentially informs on the condition of early spinosaurids. Using micro-computed tomographic scanning (μCT), we reconstruct the braincase endocasts of Baryonyx walkeri and Ceratosuchops inferodios from the Wealden Supergroup (Lower Cretaceous) of England. We show that the gross endocranial morphology is similar to other non-maniraptoriform theropods, and corroborates previous observations of overall endocranial conservatism amongst more basal theropods. Several differences of unknown taxonomic utility are noted between the pair. Baryonychine neurosensory capabilities include low-frequency hearing and unexceptional olfaction, whilst the differing morphology of the floccular lobe tentatively suggests less developed gaze stabilisation mechanisms relative to spinosaurines. Given the morphological similarities observed with other basal tetanurans, baryonychines likely possessed comparable behavioural sophistication, suggesting that the transition from terrestrial hypercarnivorous ancestors to semi-aquatic "generalists" during the evolution of Spinosauridae did not require substantial modification of the brain and sensory systems.
Collapse
Affiliation(s)
- Chris Tijani Barker
- Institute for Life Sciences, University of Southampton, University Road, Southampton, UK.,Faculty of Engineering and Physical Sciences, University of Southampton, University Road, Southampton, UK
| | - Darren Naish
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, UK
| | - Jacob Trend
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, UK
| | - Lysanne Veerle Michels
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, UK
| | - Lawrence Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio Center for Ecology and Evolutionary Studies, Ohio University, Athens, Ohio, USA
| | - Ryan Ridgley
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio Center for Ecology and Evolutionary Studies, Ohio University, Athens, Ohio, USA
| | - Katy Rankin
- μ-VIS X-ray Imaging Centre, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK
| | - Claire E Clarkin
- School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, UK
| | - Philipp Schneider
- Bioengineering Science Research Group, Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, UK.,High-Performance Vision Systems, Center for Vision, Automation and Control, AIT Austrian Institute of Technology, Vienna, Austria
| | - Neil J Gostling
- Institute for Life Sciences, University of Southampton, University Road, Southampton, UK.,School of Biological Sciences, Faculty of Environment and Life Sciences, University of Southampton, University Road, Southampton, UK
| |
Collapse
|
4
|
Schwab JA, Young MT, Walsh SA, Witmer LM, Herrera Y, Brochu CA, Butler IB, Brusatte SL. Ontogenetic variation in the crocodylian vestibular system. J Anat 2022; 240:821-832. [PMID: 34841534 PMCID: PMC9005688 DOI: 10.1111/joa.13601] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/29/2021] [Accepted: 11/19/2021] [Indexed: 01/20/2023] Open
Abstract
Crocodylians today live in tropical to subtropical environments, occupying mostly shallow waters. Their body size changes drastically during ontogeny, as do their skull dimensions and bite forces, which are associated with changes in prey preferences. Endocranial neurosensory structures have also shown to change ontogenetically, but less is known about the vestibular system of the inner ear. Here we use 30 high-resolution computed tomography (CT) scans and three-dimensional geometric morphometrics to investigate the size and shape changes of crocodylian endosseous labyrinths throughout ontogeny, across four stages (hatchling, juvenile, subadult and adult). We find two major patterns of ontogenetic change. First, the labyrinth increases in size during ontogeny, with negative allometry in relation to skull size. Second, labyrinth shape changes significantly, with hatchlings having shorter semicircular canal radii, with thicker diameters and an overall dorsoventrally shorter labyrinth than those of more mature individuals. We argue that the modification of the labyrinth during crocodylian ontogeny is related to constraints imposed by skull growth, due to fundamental changes in the crocodylian braincase during ontogeny (e.g. verticalisation of the basicranium), rather than changes in locomotion, diet, or other biological functions or behaviours.
Collapse
Affiliation(s)
- Julia A. Schwab
- School of GeoSciencesGrant InstituteUniversity of EdinburghEdinburghUK
| | - Mark T. Young
- School of GeoSciencesGrant InstituteUniversity of EdinburghEdinburghUK
| | - Stig A. Walsh
- School of GeoSciencesGrant InstituteUniversity of EdinburghEdinburghUK
- National Museum of ScotlandEdinburghUK
| | - Lawrence M. Witmer
- Department of Biomedical SciencesHeritage College of Osteopathic MedicineOhio Center for Ecology and Evolutionary StudiesOhio UniversityAthensOhioUSA
| | - Yanina Herrera
- CONICET. División Paleontología VertebradosMuseo de La Plata, FCNyMUNLPLa PlataArgentina
| | | | - Ian B. Butler
- School of GeoSciencesGrant InstituteUniversity of EdinburghEdinburghUK
| | | |
Collapse
|
5
|
Aquatic birds have middle ears adapted to amphibious lifestyles. Sci Rep 2022; 12:5251. [PMID: 35347167 PMCID: PMC8960762 DOI: 10.1038/s41598-022-09090-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 03/16/2022] [Indexed: 11/21/2022] Open
Abstract
Birds exhibit wide variation in their use of aquatic environments, on a spectrum from entirely terrestrial, through amphibious, to highly aquatic. Although there are limited empirical data on hearing sensitivity of birds underwater, mounting evidence indicates that diving birds detect and respond to sound underwater, suggesting that some modifications of the ear may assist foraging or other behaviors below the surface. In air, the tympanic middle ear acts as an impedance matcher that increases sound pressure and decreases sound vibration velocity between the outside air and the inner ear. Underwater, the impedance-matching task is reversed and the ear is exposed to high hydrostatic pressures. Using micro- and nano-CT (computerized tomography) scans of bird ears in 127 species across 26 taxonomic orders, we measured a suite of morphological traits of importance to aerial and aquatic hearing to test predictions relating to impedance-matching in birds with distinct aquatic lifestyles, while accounting for allometry and phylogeny. Birds that engage in underwater pursuit and deep diving showed the greatest differences in ear structure relative to terrestrial species. In these heavily modified ears, the size of the input areas of both the tympanic membrane and the columella footplate of the middle ear were reduced. Underwater pursuit and diving birds also typically had a shorter extrastapedius, a reduced cranial air volume and connectivity and several modifications in line with reversals of low-to-high impedance-matching. The results confirm adaptations of the middle ear to aquatic lifestyles in multiple independent bird lineages, likely facilitating hearing underwater and baroprotection, while potentially constraining the sensitivity of aerial hearing.
Collapse
|
6
|
Schwab JA, Young MT, Walsh SA, Witmer LM, Herrera Y, Timmons ZL, Butler IB, Brusatte SL. 'Ear stones' in crocodylians: a cross-species comparative and ontogenetic survey of otolith structures. ROYAL SOCIETY OPEN SCIENCE 2022; 9:211633. [PMID: 35345438 PMCID: PMC8941411 DOI: 10.1098/rsos.211633] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/25/2022] [Indexed: 05/03/2023]
Abstract
The vestibular system of the inner ear is a crucial sensory organ, involved in the sensation of balance and equilibrium. It consists of three semicircular canals that sense angular rotations of the head and the vestibule that detects linear acceleration and gravity. The vestibule often contains structures, known as the otoliths or 'ear stones'. Otoliths are present in many vertebrates and are particularly well known from the fossil record of fish, but surprisingly have not been described in detail in most tetrapods, living or extinct. Here, we present for the first time a survey of the otoliths of a broad sample of extant crocodylian species, based on computed tomography scans. We find that otoliths are present in numerous crocodylian species of different growth stages, and they continue to increase in size during ontogeny, with positive allometry compared to skull length. Our results confirm that otoliths are a common component of the crocodylian vestibular system, and suggest they play an important role in sensory detection. Otoliths are likely common, but overlooked, constituents of the inner ear in tetrapods, and a broader study of their size, shape and distribution promises insight into sensory abilities.
Collapse
Affiliation(s)
- Julia A. Schwab
- School of GeoSciences, Grant Institute, University of Edinburgh, James Hutton Road, The King's Buildings, Edinburgh EH9 3FE, UK
| | - Mark T. Young
- School of GeoSciences, Grant Institute, University of Edinburgh, James Hutton Road, The King's Buildings, Edinburgh EH9 3FE, UK
| | - Stig A. Walsh
- School of GeoSciences, Grant Institute, University of Edinburgh, James Hutton Road, The King's Buildings, Edinburgh EH9 3FE, UK
- National Museum of Scotland, Chambers Street, Edinburgh EH 1 1JF, UK
| | - Lawrence M. Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701, USA
| | - Yanina Herrera
- CONICET. División Paleontología Vertebrados, Museo de La Plata, FCNyM, UNLP, La Plata, Argentina
| | - Zena L. Timmons
- National Museum of Scotland, Chambers Street, Edinburgh EH 1 1JF, UK
| | - Ian B. Butler
- School of GeoSciences, Grant Institute, University of Edinburgh, James Hutton Road, The King's Buildings, Edinburgh EH9 3FE, UK
| | - Stephen L. Brusatte
- School of GeoSciences, Grant Institute, University of Edinburgh, James Hutton Road, The King's Buildings, Edinburgh EH9 3FE, UK
- National Museum of Scotland, Chambers Street, Edinburgh EH 1 1JF, UK
| |
Collapse
|
7
|
Lower Levels of Vestibular Developmental Stability in Slow-Moving than Fast-Moving Primates. Symmetry (Basel) 2021. [DOI: 10.3390/sym13122305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The vestibular system of the mammalian inner ear senses angular and linear velocity of the head and enables animals to maintain their balance. Vestibular anatomy has been studied extensively in order to link its structure to particular kinds of locomotion. Available evidence indicates that, in primates, slow-moving species show higher levels of vestibular variation than fast-moving taxa. We analysed intraspecific morphological variation and fluctuating asymmetry (FA) levels in the semicircular canal systems of six species of lorisiform primates: three slow-moving lorisids and three fast-moving galagids. Our results showed clear differences in levels of intraspecific variation between slow-moving and fast-moving taxa. Higher levels of variation were responsible for deviations from coplanarity for synergistic pairs of canals in slower taxa. Lorisids also presented higher levels of FA than galagids. FA is a better indicator of agility than intraspecific variation. These results suggest that in order to function efficiently in fast taxa, semicircular canal systems must develop as symmetrically as possible, and should minimise the deviation from coplanarity for synergistic pairs. Higher levels of variation and asymmetry in slow-moving taxa may be related to lower levels of stabilising selection on the vestibular system, linked to a lower demand for rapid postural changes.
Collapse
|
8
|
Tschopp E, Napoli JG, Wencker LCM, Delfino M, Upchurch P. How to Render Species Comparable Taxonomic Units Through Deep Time: a Case Study on Intraspecific Osteological Variability in Extant and Extinct Lacertid Lizards. Syst Biol 2021; 71:875-900. [PMID: 34605923 DOI: 10.1093/sysbio/syab078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 09/16/2021] [Accepted: 09/23/2021] [Indexed: 11/13/2022] Open
Abstract
Generally, the species is considered to be the only naturally occurring taxon. However, species recognised and defined using different species delimitation criteria cannot readily be compared, impacting studies of biodiversity through Deep Time. This comparability issue is particularly marked when comparing extant with extinct species, because the only available data for species delimitation in fossils is derived from their preserved morphology, which is generally restricted to osteology in vertebrates. Here, we quantify intraspecific, intrageneric, and intergeneric osteological variability in extant species of lacertid lizards using pairwise dissimilarity scores based on a dataset of 253 discrete osteological characters for 99 specimens referred to 24 species. Variability is always significantly lower intraspecifically than between individuals belonging to distinct species of a single genus, which is in turn significantly lower than intergeneric variability. Average values of intraspecific variability and associated standard deviations are consistent (with few exceptions), with an overall average within a species of 0.208 changes per character scored. Application of the same methods to six extinct lacertid species (represented by 40 fossil specimens) revealed that intraspecific osteological variability is inconsistent, which can at least in part be attributed to different researchers having unequal expectations of the skeletal dissimilarity within species units. Such a divergent interpretation of intraspecific and interspecific variability among extant and extinct species reinforces the incomparability of the species unit. Lacertidae is an example where extant species recognised and defined based on a number of delimitation criteria show comparable and consistent intraspecific osteological variability. Here, as well as in equivalent cases, application of those skeletal dissimilarity values to palaeontological species delimitation potentially provides a way to ameliorate inconsistencies created by the use of morphology to define species.
Collapse
Affiliation(s)
- Emanuel Tschopp
- Universität Hamburg, Hamburg, Germany.,Division of Paleontology, American Museum of Natural History, New York, USA.,Dipartimento di Scienze della Terra, Università di Torino, Italy.,GeoBioTec, NOVA School of Science and Technology, NOVA University Lisbon, Caparica, Portugal
| | - James G Napoli
- Division of Paleontology, American Museum of Natural History, New York, USA.,Richard Gilder Graduate School, American Museum of Natural History, New York, USA
| | | | - Massimo Delfino
- Dipartimento di Scienze della Terra, Università di Torino, Italy.,Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain
| | - Paul Upchurch
- Department of Earth Sciences, University College London, London, UK
| |
Collapse
|
9
|
Knoll F, Lautenschlager S, Kawabe S, Martínez G, Espílez E, Mampel L, Alcalá L. Palaeoneurology of the early cretaceous iguanodont Proa valdearinnoensis and its bearing on the parallel developments of cognitive abilities in theropod and ornithopod dinosaurs. J Comp Neurol 2021; 529:3922-3945. [PMID: 34333763 DOI: 10.1002/cne.25224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 11/10/2022]
Abstract
Proa valdearinnoensis is a relatively large-headed and stocky iguanodontian dinosaur from the latest Early Cretaceous of Spain. Its braincase is known from three specimens. Similar to that of other dinosaurs, it shows a mosaic ossification pattern in which most of the bones seem to have fused together indistinguishably while a few (frontoparietal, basioccipital) might have remained loosely attached. The endocasts of the three specimens are described based on CT data and digital reconstructions. They show unmistakable morphological similarities with the endocast of closely related taxa, such as Sirindhorna khoratensis (which is close in age but from Thailand). This supports a high conservatism of the endocranial cavity. The issue of volumetric correspondence between endocranial cavity and brain in dinosaurs is analyzed. Although a brain-to-endocranial cavity (BEC) index of 0.50 has been traditionally used, we employ instead 0.73. This is indeed the mid-value between the situation in adults of Alligator mississippiensis and Gallus gallus, which are members of the extant bracketing taxa of dinosaurs (Crocodilia and Aves). We thence gauge the level of encephalization of P. valdearinnoensis through the calculation of the encephalization quotient (EQ), which remains valuable as a metric for assessing the degree of cognitive function in extinct taxa, especially those with fully ossified braincases like dinosaurs and other archosaurs. The EQ obtained for P. valdearinnoensis (3.611) suggests that this species was significantly more encephalized than most if not all extant nonavian, nonmammalian amniotes. Our work adds to the growing body of data concerning theoretical cognitive capabilities in dinosaurs and supports the idea that an increasing encephalization was fostered not only in theropods but also in parallel in the shorter-lived lineage of ornithopods. P. valdearinnoensis was ill-equipped to respond to theropod dinosaurs and possibly lived in groups as a strategy to mitigate the risk of being predated upon. We hypothesize that group-living and protracted caring of juveniles in this and possibly many other iguanodontian ornithopods favored a degree of encephalization that was outstanding by reptile standards.
Collapse
Affiliation(s)
- Fabien Knoll
- Fundación ARAID, Zaragoza, Spain.,Fundación Conjunto Paleontológico de Teruel-Dinópolis, Teruel, Spain.,Departamento de Paleobiología, Museo Nacional de Ciencias Naturales-CSIC, Madrid, Spain
| | - Stephan Lautenschlager
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Soichiro Kawabe
- Institute of Dinosaur Research, Fukui Prefectural University, Fukui, Japan.,Fukui Prefectural Dinosaur Museum, Fukui, Japan
| | - Gloria Martínez
- Servicio de Radiodiagnóstico, Hospital General Obispo Polanco, Teruel, Spain
| | - Eduardo Espílez
- Fundación Conjunto Paleontológico de Teruel-Dinópolis, Teruel, Spain
| | - Luis Mampel
- Fundación Conjunto Paleontológico de Teruel-Dinópolis, Teruel, Spain
| | - Luis Alcalá
- Fundación Conjunto Paleontológico de Teruel-Dinópolis, Teruel, Spain
| |
Collapse
|
10
|
Hanson M, Hoffman EA, Norell MA, Bhullar BAS. The early origin of a birdlike inner ear and the evolution of dinosaurian movement and vocalization. Science 2021; 372:601-609. [PMID: 33958471 DOI: 10.1126/science.abb4305] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 03/09/2021] [Indexed: 12/27/2022]
Abstract
Reptiles, including birds, exhibit a range of behaviorally relevant adaptations that are reflected in changes to the structure of the inner ear. These adaptations include the capacity for flight and sensitivity to high-frequency sound. We used three-dimensional morphometric analyses of a large sample of extant and extinct reptiles to investigate inner ear correlates of locomotor ability and hearing acuity. Statistical analyses revealed three vestibular morphotypes, best explained by three locomotor categories-quadrupeds, bipeds and simple fliers (including bipedal nonavialan dinosaurs), and high-maneuverability fliers. Troodontids fall with Archaeopteryx among the extant low-maneuverability fliers. Analyses of cochlear shape revealed a single instance of elongation, on the stem of Archosauria. We suggest that this transformation coincided with the origin of both high-pitched juvenile location, alarm, and hatching-synchronization calls and adult responses to them.
Collapse
Affiliation(s)
- Michael Hanson
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA.,Peabody Museum of Natural History, Yale University, New Haven, CT, USA
| | - Eva A Hoffman
- Division of Paleontology, American Museum of Natural History, New York, NY, USA
| | - Mark A Norell
- Division of Paleontology, American Museum of Natural History, New York, NY, USA
| | - Bhart-Anjan S Bhullar
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, USA. .,Peabody Museum of Natural History, Yale University, New Haven, CT, USA
| |
Collapse
|
11
|
King JL, Sipla JS, Georgi JA, Balanoff AM, Neenan JM. The endocranium and trophic ecology of Velociraptor mongoliensis. J Anat 2020; 237:861-869. [PMID: 32648601 PMCID: PMC7542195 DOI: 10.1111/joa.13253] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/30/2020] [Accepted: 05/22/2020] [Indexed: 12/20/2022] Open
Abstract
Neuroanatomical reconstructions of extinct animals have long been recognized as powerful proxies for palaeoecology, yet our understanding of the endocranial anatomy of dromaeosaur theropod dinosaurs is still incomplete. Here, we used X‐ray computed microtomography (µCT) to reconstruct and describe the endocranial anatomy, including the endosseous labyrinth of the inner ear, of the small‐bodied dromaeosaur, Velociraptor mongoliensis. The anatomy of the cranial endocast and ear were compared with non‐avian theropods, modern birds, and other extant archosaurs to establish trends in agility, balance, and hearing thresholds in order to reconstruct the trophic ecology of the taxon. Our results indicate that V. mongoliensis could detect a wide and high range of sound frequencies (2,368–3,965 Hz), was agile, and could likely track prey items with ease. When viewed in conjunction with fossils that suggest scavenging‐like behaviours in V. mongoliensis, a complex trophic ecology that mirrors modern predators becomes apparent. These data suggest that V. mongoliensis was an active predator that would likely scavenge depending on the age and health of the individual or during prolonged climatic events such as droughts.
Collapse
Affiliation(s)
- J Logan King
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - Justin S Sipla
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA, USA
| | - Justin A Georgi
- Department of Anatomy, Midwestern University, Glendale, AZ, USA
| | - Amy M Balanoff
- Division of Paleontology, American Museum of Natural History, New York, NY, USA.,Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - James M Neenan
- Oxford University Museum of Natural History, University of Oxford, Oxford, UK
| |
Collapse
|
12
|
Schwab JA, Young MT, Neenan JM, Walsh SA, Witmer LM, Herrera Y, Allain R, Brochu CA, Choiniere JN, Clark JM, Dollman KN, Etches S, Fritsch G, Gignac PM, Ruebenstahl A, Sachs S, Turner AH, Vignaud P, Wilberg EW, Xu X, Zanno LE, Brusatte SL. Inner ear sensory system changes as extinct crocodylomorphs transitioned from land to water. Proc Natl Acad Sci U S A 2020; 117:10422-10428. [PMID: 32312812 PMCID: PMC7229756 DOI: 10.1073/pnas.2002146117] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Major evolutionary transitions, in which animals develop new body plans and adapt to dramatically new habitats and lifestyles, have punctuated the history of life. The origin of cetaceans from land-living mammals is among the most famous of these events. Much earlier, during the Mesozoic Era, many reptile groups also moved from land to water, but these transitions are more poorly understood. We use computed tomography to study changes in the inner ear vestibular system, involved in sensing balance and equilibrium, as one of these groups, extinct crocodile relatives called thalattosuchians, transitioned from terrestrial ancestors into pelagic (open ocean) swimmers. We find that the morphology of the vestibular system corresponds to habitat, with pelagic thalattosuchians exhibiting a more compact labyrinth with wider semicircular canal diameters and an enlarged vestibule, reminiscent of modified and miniaturized labyrinths of other marine reptiles and cetaceans. Pelagic thalattosuchians with modified inner ears were the culmination of an evolutionary trend with a long semiaquatic phase, and their pelagic vestibular systems appeared after the first changes to the postcranial skeleton that enhanced their ability to swim. This is strikingly different from cetaceans, which miniaturized their labyrinths soon after entering the water, without a prolonged semiaquatic stage. Thus, thalattosuchians and cetaceans became secondarily aquatic in different ways and at different paces, showing that there are different routes for the same type of transition.
Collapse
Affiliation(s)
- Julia A Schwab
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom;
| | - Mark T Young
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
| | - James M Neenan
- Oxford University Museum of Natural History, OX1 3PW Oxford, United Kingdom
| | - Stig A Walsh
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
- Department of Natural Sciences, National Museum of Scotland, EH1 1JF Edinburgh, United Kingdom
| | - Lawrence M Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701
| | - Yanina Herrera
- Consejo Nacional de Investigaciones Científicas y Técnicas, División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, National University of La Plata, B1900 La Plata, Buenos Aires, Argentina
| | - Ronan Allain
- Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements, Muséum National d'Histoire Naturelle, 75005 Paris, France
| | - Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA 52242
| | - Jonah N Choiniere
- Evolutionary Studies Institute, University of the Witwatersrand, 2000 Johannesburg, South Africa
| | - James M Clark
- Department of Biological Sciences, George Washington University, Washington, DC 20052
| | - Kathleen N Dollman
- Evolutionary Studies Institute, University of the Witwatersrand, 2000 Johannesburg, South Africa
- School of Geosciences, University of the Witwatersrand, 2000 Johannesburg, South Africa
| | - Steve Etches
- Museum of Jurassic Marine Life, BH20 5PE Kimmeridge, United Kingdom
| | - Guido Fritsch
- Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany
| | - Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107
| | | | - Sven Sachs
- Abteilung Geowissenschaften, Naturkunde-Museum Bielefeld, Abteilung Geowissenschaften, 33602 Bielefeld, Germany
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794
| | - Patrick Vignaud
- Laboratoire de Paléontologie, Evolution, Paléoécosystèmes et Paléoprimatologie, CNRS UMR 7262, Department of Geosciences, University of Poitiers, 86073 Poitiers Cedex 9, France
| | - Eric W Wilberg
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794
| | - Xing Xu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 100044 Beijing, China
| | - Lindsay E Zanno
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC 27601
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695
| | - Stephen L Brusatte
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
- Department of Natural Sciences, National Museum of Scotland, EH1 1JF Edinburgh, United Kingdom
| |
Collapse
|
13
|
Schwab JA, Young MT, Neenan JM, Walsh SA, Witmer LM, Herrera Y, Allain R, Brochu CA, Choiniere JN, Clark JM, Dollman KN, Etches S, Fritsch G, Gignac PM, Ruebenstahl A, Sachs S, Turner AH, Vignaud P, Wilberg EW, Xu X, Zanno LE, Brusatte SL. Inner ear sensory system changes as extinct crocodylomorphs transitioned from land to water. Proc Natl Acad Sci U S A 2020. [PMID: 32312812 DOI: 10.11073/pnas.2002146117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/18/2023] Open
Abstract
Major evolutionary transitions, in which animals develop new body plans and adapt to dramatically new habitats and lifestyles, have punctuated the history of life. The origin of cetaceans from land-living mammals is among the most famous of these events. Much earlier, during the Mesozoic Era, many reptile groups also moved from land to water, but these transitions are more poorly understood. We use computed tomography to study changes in the inner ear vestibular system, involved in sensing balance and equilibrium, as one of these groups, extinct crocodile relatives called thalattosuchians, transitioned from terrestrial ancestors into pelagic (open ocean) swimmers. We find that the morphology of the vestibular system corresponds to habitat, with pelagic thalattosuchians exhibiting a more compact labyrinth with wider semicircular canal diameters and an enlarged vestibule, reminiscent of modified and miniaturized labyrinths of other marine reptiles and cetaceans. Pelagic thalattosuchians with modified inner ears were the culmination of an evolutionary trend with a long semiaquatic phase, and their pelagic vestibular systems appeared after the first changes to the postcranial skeleton that enhanced their ability to swim. This is strikingly different from cetaceans, which miniaturized their labyrinths soon after entering the water, without a prolonged semiaquatic stage. Thus, thalattosuchians and cetaceans became secondarily aquatic in different ways and at different paces, showing that there are different routes for the same type of transition.
Collapse
Affiliation(s)
- Julia A Schwab
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom;
| | - Mark T Young
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
| | - James M Neenan
- Oxford University Museum of Natural History, OX1 3PW Oxford, United Kingdom
| | - Stig A Walsh
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
- Department of Natural Sciences, National Museum of Scotland, EH1 1JF Edinburgh, United Kingdom
| | - Lawrence M Witmer
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701
| | - Yanina Herrera
- Consejo Nacional de Investigaciones Científicas y Técnicas, División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, National University of La Plata, B1900 La Plata, Buenos Aires, Argentina
| | - Ronan Allain
- Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements, Muséum National d'Histoire Naturelle, 75005 Paris, France
| | - Christopher A Brochu
- Department of Earth and Environmental Sciences, University of Iowa, Iowa City, IA 52242
| | - Jonah N Choiniere
- Evolutionary Studies Institute, University of the Witwatersrand, 2000 Johannesburg, South Africa
| | - James M Clark
- Department of Biological Sciences, George Washington University, Washington, DC 20052
| | - Kathleen N Dollman
- Evolutionary Studies Institute, University of the Witwatersrand, 2000 Johannesburg, South Africa
- School of Geosciences, University of the Witwatersrand, 2000 Johannesburg, South Africa
| | - Steve Etches
- Museum of Jurassic Marine Life, BH20 5PE Kimmeridge, United Kingdom
| | - Guido Fritsch
- Department of Reproduction Management, Leibniz Institute for Zoo and Wildlife Research, 10315 Berlin, Germany
| | - Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107
| | | | - Sven Sachs
- Abteilung Geowissenschaften, Naturkunde-Museum Bielefeld, Abteilung Geowissenschaften, 33602 Bielefeld, Germany
| | - Alan H Turner
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794
| | - Patrick Vignaud
- Laboratoire de Paléontologie, Evolution, Paléoécosystèmes et Paléoprimatologie, CNRS UMR 7262, Department of Geosciences, University of Poitiers, 86073 Poitiers Cedex 9, France
| | - Eric W Wilberg
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794
| | - Xing Xu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, 100044 Beijing, China
| | - Lindsay E Zanno
- Paleontology, North Carolina Museum of Natural Sciences, Raleigh, NC 27601
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695
| | - Stephen L Brusatte
- School of GeoSciences, Grant Institute, University of Edinburgh, EH9 3FE Edinburgh, United Kingdom
- Department of Natural Sciences, National Museum of Scotland, EH1 1JF Edinburgh, United Kingdom
| |
Collapse
|
14
|
Dudgeon TW, Maddin HC, Evans DC, Mallon JC. The internal cranial anatomy of Champsosaurus (Choristodera: Champsosauridae): Implications for neurosensory function. Sci Rep 2020; 10:7122. [PMID: 32346021 PMCID: PMC7188685 DOI: 10.1038/s41598-020-63956-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 04/06/2020] [Indexed: 11/09/2022] Open
Abstract
Although isolated Champsosaurus remains are common in Upper Cretaceous sediments of North America, the braincase of these animals is enigmatic due to the fragility of their skulls. Here, two well-preserved specimens of Champsosaurus (CMN 8920 and CMN 8919) are CT scanned to describe their neurosensory structures and infer sensory capability. The anterior portion of the braincase was poorly ossified and thus does not permit visualization of a complete endocast; however, impressions of the olfactory stalks indicate that they were elongate and likely facilitated good olfaction. The posterior portion of the braincase is ossified and morphologically similar to that of other extinct diapsids. The absence of an otic notch and an expansion of the pars inferior of the inner ear suggests Champsosaurus was limited to detecting low frequency sounds. Comparison of the shapes of semicircular canals with lepidosaurs and archosauromorphs demonstrates that the semicircular canals of Champsosaurus are most similar to those of aquatic reptiles, suggesting that Champsosaurus was well adapted for sensing movement in an aquatic environment. This analysis also demonstrates that birds, non-avian archosauromorphs, and lepidosaurs possess significantly different canal morphologies, and represents the first morphometric analysis of semicircular canals across Diapsida.
Collapse
Affiliation(s)
- Thomas W Dudgeon
- Department of Earth Sciences, Carleton University, Ottawa, Canada.
| | - Hillary C Maddin
- Department of Earth Sciences, Carleton University, Ottawa, Canada
| | - David C Evans
- Vertebrate Palaeontology, Royal Ontario Museum, Toronto, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Jordan C Mallon
- Department of Earth Sciences, Carleton University, Ottawa, Canada.,Beaty Centre for Species Discovery and Palaeobiology Section, Canadian Museum of Nature, Ottawa, Canada
| |
Collapse
|