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Pusch LC, Kammerer CF, Fröbisch J. The origin and evolution of Cynodontia (Synapsida, Therapsida): Reassessment of the phylogeny and systematics of the earliest members of this clade using 3D-imaging technologies. Anat Rec (Hoboken) 2024; 307:1634-1730. [PMID: 38444024 DOI: 10.1002/ar.25394] [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: 10/12/2023] [Revised: 01/13/2024] [Accepted: 01/14/2024] [Indexed: 03/07/2024]
Abstract
The origin of cynodonts, the group ancestral to and including mammals, is one of the major outstanding problems in therapsid evolution. One of the most troubling aspects of the cynodont fossil record is the lengthy Permian ghost lineage between the latest possible divergence from its sister group Therocephalia and the first appearance of definitive cynodonts in the late Permian. The absence of cynodonts and dominance of therocephalians in middle Permian strata has led some workers to argue that cynodonts evolved from within therocephalians, rendering the latter paraphyletic, but more recent analyses support the reciprocal monophyly of Cynodontia and Therocephalia. Furthermore, although a fundamental dichotomy in the derived subclade Eucynodontia is well-supported in cynodont phylogeny, the relationships of more stemward cynodonts from the late Permian and Early Triassic are unresolved. Here, we provide a re-evaluation of the phylogeny of Eutheriodontia (Cynodontia + Therocephalia) and an assessment of character evolution within the group. Using computed tomographic data derived from extensive sampling of the earliest known (late Permian and Early Triassic) cynodonts and selected exemplars of therocephalians and later (Middle Triassic onwards) cynodonts, we describe novel aspects of the endocranial anatomy of these animals. These data were incorporated into a new phylogenetic data set including a comprehensive sample of early cynodonts. Our phylogenetic analyses support some results previously recovered by other authors, but recover therocephalians as paraphyletic with regards to cynodonts, with cynodonts and eutherocephalians forming a clade to the exclusion of the "basal therocephalian" families Lycosuchidae and Scylacosauridae. Though both conservatism and homoplasy mark the endocranial anatomy of early non-mammalian cynodonts, we were able to identify several new endocranial synapomorphies for eutheriodont subclades and recovered generally better-supported topologies than previous analyses using primarily external craniodental characters.
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Affiliation(s)
- Luisa C Pusch
- Museum für Naturkunde, Leibniz-Institut füsr Evolutions- und Biodiversitätsforschung, Berlin, Germany
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Christian F Kammerer
- North Carolina Museum of Natural Sciences, Raleigh, North Carolina, USA
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Jörg Fröbisch
- Museum für Naturkunde, Leibniz-Institut füsr Evolutions- und Biodiversitätsforschung, Berlin, Germany
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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2
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Kerber L, Roese-Miron L, Bubadué JM, Martinelli AG. Endocranial anatomy of the early prozostrodonts (Eucynodontia: Probainognathia) and the neurosensory evolution in mammal forerunners. Anat Rec (Hoboken) 2024; 307:1442-1473. [PMID: 37017195 DOI: 10.1002/ar.25215] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 03/09/2023] [Accepted: 03/09/2023] [Indexed: 04/06/2023]
Abstract
Prozostrodon brasiliensis and Therioherpeton cargnini are non-mammaliaform cynodonts that lived ~233 million years ago (late Carnian, Late Triassic) in western Gondwana. They represent some of the earliest divergent members of the clade Prozostrodontia, which includes "tritheledontids", tritylodontids, "brasilodontids", and mammaliaforms (including Mammalia as crown group). Here, we studied the endocranial anatomy (cranial endocast, nerves, vessels, ducts, ear region, and nasal cavity) of these two species. Our findings suggest that during the Carnian, early prozostrodonts had a brain with well-developed olfactory bulbs, expanded cerebral hemispheres divided by the interhemispheric sulcus, and absence of an unossified zone and pineal body. The morphology of the maxillary canal represents the necessary condition for the presence of facial vibrissae. A slight decrease in encephalization is observed at the origin of the clade Prozostrodontia. This new anatomical information provides evidence for the evolution of endocranial traits of the first prozotrodonts, a Late Triassic lineage that culminated in the origin of mammals.
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Affiliation(s)
- Leonardo Kerber
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Universidade Federal de Santa Maria (CAPPA/UFSM), São João do Polêsine, RS, Brazil
| | - Lívia Roese-Miron
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
- Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Universidade Federal de Santa Maria (CAPPA/UFSM), São João do Polêsine, RS, Brazil
| | - Jamile M Bubadué
- Laboratorio de Ciências Ambientais, Universidade Estadual do Norte Fluminense Darcy Ribeiro, Campos dos Goytacazes, Brazil
| | - Agustín G Martinelli
- Sección Paleontologia de Vertebrados, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Buenos Aires, Argentina
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Laaß M, Kaestner A. Nasal turbinates of the dicynodont Kawingasaurus fossilis and the possible impact of the fossorial habitat on the evolution of endothermy. J Morphol 2023; 284:e21621. [PMID: 37585231 DOI: 10.1002/jmor.21621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 08/17/2023]
Abstract
The nasal region of the fossorial anomodont Kawingasaurus fossilis was virtually reconstructed from neutron-computed tomographic data and compared with the terrestrial species Pristerodon mackayi and other nonmammalian synapsids. The tomography of the Kawingasaurus skull reveals a pattern of maxillo-, naso-, fronto- and ethmoturbinal ridges that strongly resemble the mammalian condition. On both sides of the nasal cavity, remains of scrolled maxilloturbinals were preserved that were still partially articulated with maxilloturbinal ridges. Furthermore, possible remains of the lamina semicircularis as well as fronto- or ethmoturbinals were found. In Kawingasaurus, the maxilloturbinal ridges were longer and stronger than in Pristerodon. Except for the nasoturbinal ridges, no other ridges in the olfactory region and no remains of turbinates were recognized. This supports the hypothesis that naso-, fronto-, ethmo- and maxilloturbinals were a plesiomorphic feature of synapsids, but due to their cartilaginous nature in most taxa were, in almost all cases, not preserved. The well-developed maxilloturbinals in Kawingasaurus were probably an adaptation to hypoxia-induced hyperventilation in the fossorial habitat, maintaining the high oxygen demands of Kawingasaurus' large brain. The surface area of the respiratory turbinates in Kawingasaurus falls into the mammalian range, which suggests that they functioned as a countercurrent exchange system for thermoregulation and conditioning of the respiratory airflow. Our results suggest that the environmental conditions of the fossorial habitat led to specific sensory adaptations, accompanied by a pulse in brain evolution and of endothermy in cistecephalids, ~50 million years before the origin of endothermy in the mammalian stem line. This supports the Nocturnal Bottleneck Theory, in that we found evidence for a similar evolutionary scenario in cistecephalids as proposed for early mammals.
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Affiliation(s)
- Michael Laaß
- Fakultät für Geowissenschaften, Geotechnik und Bergbau, TU Bergakademie Freiberg, Freiberg, Germany
- FRM II and Physics E21, Technische Universität München, Garching, Germany
| | - Anders Kaestner
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, Switzerland
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Bendel EM, Kammerer CF, Smith RMH, Fröbisch J. The postcranial anatomy of Gorgonops torvus (Synapsida, Gorgonopsia) from the late Permian of South Africa. PeerJ 2023; 11:e15378. [PMID: 37434869 PMCID: PMC10332358 DOI: 10.7717/peerj.15378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 04/18/2023] [Indexed: 07/13/2023] Open
Abstract
Gorgonopsians are among the most recognizable groups of synapsids from the Permian period and have an extensive but mostly cranial fossil record. By contrast, relatively little is known about their postcranial anatomy. Here, we describe a nearly complete, semi-articulated skeleton of a gorgonopsian (identified as Gorgonops torvus) from the late Permian Endothiodon Assemblage Zone of the South African Karoo Basin and discuss its paleobiological implications. Known gorgonopsian postcrania indicate morphological conservatism in the group, but the skeletal anatomy of Gorgonops does differ from that of other gorgonopsians in some respects, such as in the triangular radiale and short terminal phalanges in the manus, and a weakly developed distinction between pubis and ischium in ventral aspect of the pelvic girdle. Similarities between the specimen described herein and a historically problematic specimen originally referred to "Scymnognathus cf. whaitsi" confirm referral of the latter specimen to Gorgonops. Since descriptions of gorgonopsian postcrania are rare, new interpretations of the lifestyle and ecology of Gorgonopsia can be drawn from our contribution. We conclude that gorgonopsians were likely ambush predators, able to chase their prey over short distances and pin them down with strong forelimbs before using their canines for the kill. This is evidenced by their different fore- and hindlimb morphology; the former stouter and more robust in comparison to the longer, more gracile, back legs. Furthermore, the completeness of the study specimen facilitates calculation of an estimated body mass of approximately 98 kg, similar to that of a modern lioness.
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Affiliation(s)
- Eva-Maria Bendel
- Institut für Biologie, Humboldt Universität zu Berlin, Berlin, Germany
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
| | - Christian F. Kammerer
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
- North Carolina Museum of Natural Sciences, Raleigh, North Carolina, United States of America
| | - Roger M. H. Smith
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
- Department of Karoo Palaeontology, Iziko South African Museum, Cape Town, South Africa
| | - Jörg Fröbisch
- Institut für Biologie, Humboldt Universität zu Berlin, Berlin, Germany
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
- Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Museum für Naturkunde, Berlin, Germany
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Bazzana-Adams KD, Evans DC, Reisz RR. Neurosensory anatomy and function in Dimetrodon, the first terrestrial apex predator. iScience 2023; 26:106473. [PMID: 37096050 PMCID: PMC10122045 DOI: 10.1016/j.isci.2023.106473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 02/16/2023] [Accepted: 03/19/2023] [Indexed: 04/05/2023] Open
Abstract
Dimetrodon is among the most recognizable fossil taxa, as well as the earliest terrestrial amniote apex predator. The neuroanatomy and auditory abilities of Dimetrodon has long been the subject of interest, but palaeoneurological analyses have been limited by the lack of three-dimensional endocast data. The first virtual endocasts reveal a strongly flexed brain with enlarged floccular fossae and a surprisingly well-ossified bony labyrinth clearly preserving the semicircular canals, along with an undifferentiated vestibule and putative perilymphatic duct. This first detailed palaeoneurological reconstruction reveals potential adaptations for a predatory lifestyle and suggests Dimetrodon was able to hear a wider range of frequencies than anticipated, potentially being sensitive to frequencies equal to or higher than many extant sauropsids, despite lacking an impedance matching ear. Ancestral state reconstructions support the long-standing view of Dimetrodon as representative of the ancestral state for therapsids, while underscoring the importance of validating reconstructive analyses with fossil data.
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At the root of the mammalian mind: The sensory organs, brain and behavior of pre-mammalian synapsids. PROGRESS IN BRAIN RESEARCH 2023; 275:25-72. [PMID: 36841570 DOI: 10.1016/bs.pbr.2022.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
All modern mammals are descendants of the paraphyletic non-mammaliaform Synapsida, colloquially referred to as the "mammal-like reptiles." It has long been assumed that these mammalian ancestors were essentially reptile-like in their morphology, biology, and behavior, i.e., they had a small brain, displayed simple behavior, and their sensory organs were unrefined compared to those of modern mammals. Recent works have, however, revealed that neurological, sensory, and behavioral traits previously considered typically mammalian, such as whiskers, enhanced olfaction, nocturnality, parental care, and complex social interactions evolved before the origin of Mammaliaformes, among the early-diverging "mammal-like reptiles." In contrast, an enlarged brain did not evolve immediately after the origin of mammaliaforms. As such, in terms of paleoneurology, the last "mammal-like reptiles" were not significantly different from the earliest mammaliaforms. The abundant data and literature published in the last 10 years no longer supports the "three pulses" scenario of synapsid brain evolution proposed by Rowe and colleagues in 2011, but supports the new "outside-in" model of Rodrigues and colleagues proposed in 2018, instead. As Mesozoic reptiles were becoming the dominant taxa within terrestrial ecosystems, synapsids gradually adapted to smaller body sizes and nocturnality. This resulted in a sensory revolution in synapsids as olfaction, audition, and somatosensation compensated for the loss of visual cues. This altered sensory input is aligned with changes in the brain, the most significant of which was an increase in relative brain size.
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Bazzana KD, Evans DC, Bevitt JJ, Reisz RR. Neurosensory anatomy of Varanopidae and its implications for early synapsid evolution. J Anat 2022; 240:833-849. [PMID: 34775594 PMCID: PMC9005680 DOI: 10.1111/joa.13593] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/04/2021] [Accepted: 11/04/2021] [Indexed: 12/11/2022] Open
Abstract
Varanopids are a group of Palaeozoic terrestrial amniotes which represent one of the earliest-diverging groups of synapsids, but their palaeoneurology has gone largely unstudied and recent analyses have challenged their traditional placement within synapsids. We utilized computed tomography (CT) to study the virtual cranial and otic endocasts of six varanopids, including representative taxa of both mycterosaurines and varanodontines. Our results show that the varanopid brain is largely plesiomorphic, being tubular in shape and showing no expansion of the cerebrum or olfactory bulbs, but is distinct in showing highly expanded floccular fossae. The housing of the varanopid bony labyrinth is also distinct, in that the labyrinth is bounded almost entirely by the supraoccipital-opisthotic complex, with the prootic only bordering the ventral portion of the vestibule. The bony labyrinth is surprisingly well-ossified, clearly preserving the elliptical, sub-orthogonal canals, prominent ampullae, and the short, undifferentiated vestibule; this high degree of ossification is similar to that seen in therapsid synapsids and supports the traditional placement of varanopids within Synapsida. The enlarged anterior canal, together with the elliptical, orthogonal canals and enlarged floccular fossa, lend support for the fast head movements indicated by the inferred predatory feeding mode of varanopids. Reconstructed neurosensory anatomy indicates that varanopids may have a much lower-frequency hearing range compared to more derived synapsids, suggesting that, despite gaining some active predatory features, varanopids retain plesiomorphic hearing capabilities. As a whole, our data reveal that the neuroanatomy of pelycosaur-grade synapsids is far more complex than previously anticipated.
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Affiliation(s)
- Kayla D. Bazzana
- Department of BiologyUniversity of Toronto MississaugaMississaugaCanada
- Department of Natural HistoryRoyal Ontario MuseumTorontoCanada
| | - David C. Evans
- Department of Natural HistoryRoyal Ontario MuseumTorontoCanada
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoCanada
| | - Joseph J. Bevitt
- Australian Centre for Neutron ScatteringAustralian Nuclear Science and Technology OrganisationLucas HeightsNew South WhalesAustralia
| | - Robert R. Reisz
- Department of BiologyUniversity of Toronto MississaugaMississaugaCanada
- International Center of Future ScienceDinosaur Evolution Research CenterJilin UniversityChangchunJilin ProvinceChina
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9
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Olroyd SL, LeBlanc ARH, Araújo R, Angielczyk KD, Duhamel A, Benoit J, Amaral M. Histology and μCT reveal the unique evolution and development of multiple tooth rows in the synapsid Endothiodon. Sci Rep 2021; 11:16875. [PMID: 34413357 PMCID: PMC8377087 DOI: 10.1038/s41598-021-95993-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 07/27/2021] [Indexed: 02/07/2023] Open
Abstract
Several amniote lineages independently evolved multiple rows of marginal teeth in response to the challenge of processing high fiber plant matter. Multiple tooth rows develop via alterations to tooth replacement in captorhinid reptiles and ornithischian dinosaurs, but the specific changes that produce this morphology differ, reflecting differences in their modes of tooth attachment. To further understand the mechanisms by which multiple tooth rows can develop, we examined this feature in Endothiodon bathystoma, a member of the only synapsid clade (Anomodontia) to evolve a multi-rowed marginal dentition. We histologically sampled Endothiodon mandibles with and without multiple tooth rows as well as single-rowed maxillae. We also segmented functional and replacement teeth in µ-CT scanned mandibles and maxillae of Endothiodon and several other anomodonts with 'postcanine' teeth to characterize tooth replacement in the clade. All anomodonts in our sample displayed a space around the tooth roots for a soft tissue attachment between tooth and jaw in life. Trails of alveolar bone indicate varying degrees of labial migration of teeth through ontogeny, often altering the spatial relationships of functional and replacement teeth in the upper and lower jaws. We present a model of multiple tooth row development in E. bathystoma in which labial migration of functional teeth was extensive enough to prevent resorption and replacement by newer generations of teeth. This model represents another mechanism by which multiple tooth rows evolved in amniotes. The multiple tooth rows of E. bathystoma may have provided more extensive contact between the teeth and a triturating surface on the palatine during chewing.
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Affiliation(s)
| | - Aaron R H LeBlanc
- Centre for Oral, Clinical & Translational Sciences, King's College London, London, UK
| | - Ricardo Araújo
- Instituto de Plasmas e Fusão Nuclear, Universidade de Lisboa, Lisbon, Portugal
| | - Kenneth D Angielczyk
- Negaunee Integrative Research Center, Field Museum of Natural History, Chicago, USA
| | - Aliénor Duhamel
- Evolutionary Studies Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Julien Benoit
- Evolutionary Studies Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
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Kerber L, Ferreira JD, Fonseca PHM, Franco A, Martinelli AG, Soares MB, Ribeiro AM. An additional brain endocast of the ictidosaur Riograndia guaibensis (Eucynodontia: Probainognathia): intraspecific variation of endocranial traits. AN ACAD BRAS CIENC 2021; 93:e20200084. [PMID: 33681891 DOI: 10.1590/0001-3765202120200084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 07/08/2020] [Indexed: 11/22/2022] Open
Abstract
Recently, the morphology and encephalization of the brain endocast of the Triassic non-mammaliaform probainognathian cynodont Riograndia guaibensis were studied. Here, we analyzed the brain endocast of an additional specimen of this species. The new endocast shows well-defined olfactory bulbs and a median sulcus dividing the hemispheres, traits that were not clearly observed in the first studied specimen. Encephalization quotients were also calculated, revealing similar values to other non-mammaliaform cynodonts and lower than those of the first analyzed specimen. The analyzed cranium is slightly larger than the first studied one and may represent an advanced ontogenetic stage. Hence, these differences may be related to the intraspecific variation of this cynodont or alternatively, to the preservation of each specimen.
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Affiliation(s)
- Leonardo Kerber
- Universidade Federal de Santa Maria, Centro de Apoio à Pesquisa Paleontológica, Rua Maximiliano Vizzotto, 598, 97230-000 São João do Polêsine, RS, Brazil.,Museu Paraense Emílio Goeldi, Coordenação de Ciências da Terra e Ecologia, Av. Perimetral, 1901, 66077-830 Belém, PA, Brazil.,Universidade Federal de Santa Maria, Programa de Pós-Graduação em Biodiversidade Animal, Av. Roraima 1000, 97105-900 Santa Maria, RS, Brazil
| | - JosÉ Darival Ferreira
- Universidade Federal de Santa Maria, Programa de Pós-Graduação em Biodiversidade Animal, Av. Roraima 1000, 97105-900 Santa Maria, RS, Brazil
| | - Pedro Henrique M Fonseca
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Arymatheia Franco
- Universidade Federal de Santa Maria, Programa de Pós-Graduação em Biodiversidade Animal, Av. Roraima 1000, 97105-900 Santa Maria, RS, Brazil
| | - AgustÍn G Martinelli
- Museo Argentino de Ciencias Naturales 'Bernardino Rivadavia', CONICET-Sección Paleontología de Vertebrados, Av. Ángel Gallardo, 470, C1405 DJR, Buenos Aires, Argentina
| | - Marina Bento Soares
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil.,Universidade Federal do Rio de Janeiro, Museu Nacional, Departamento de Geologia e Paleontologia, Quinta da Boa Vista, São Cristóvão, 20940-040 Rio de Janeiro, RJ, Brazil
| | - Ana Maria Ribeiro
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil.,Secretaria do Meio Ambiente e Infraestrutura, Museu de Ciências Naturais, Seção de Paleontologia, Av. Salvador França, 1427, 90690-000 Porto Alegre, RS, Brazil
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11
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Liu J. The tetrapod fauna of the upper Permian Naobaogou Formation of China: 6. Turfanodon jiufengensis sp. nov. (Dicynodontia). PeerJ 2021; 9:e10854. [PMID: 33643709 PMCID: PMC7896508 DOI: 10.7717/peerj.10854] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 01/06/2021] [Indexed: 11/20/2022] Open
Abstract
The dicynodont fossils from the Naobaogou Formation of Nei Mongol, China are abundant and diverse but poorly studied. In this article, one nearly complete skeleton and four cranial specimens from the Naobaogou Formation are referred to the dicynodontoid genus Turfanodon as a new species, T. jiufengensis. Previously, Turfanodon was known only from upper Permian sites in Xinjiang and Gansu. The new specimens are referred to Turfanodon based on the following characters: snout tall with steeply sloping profile, anterior tip of the snout squared off, facial region heavily pitted, nasal bosses present as paired swellings near the posterodorsal margin of the external nares, preparietal depressed, intertemporal bar long and narrow, premaxilla contacting frontal, palatal surface of premaxilla exposed in lateral view, and anterior pterygoid keel restricted to the anterior tip of the anterior ramus of the pterygoid. Turfanodon jiufengensis is differentiated from the type species, T. bogdaensis, by a contact of the lacrimal with the septomaxilla, discrete, raised nasal bosses, the dorsal edge of the erupted portion of the canine tusk slightly posterior to the anterior orbital margin, an anterior extension of the lacrimal distinctly shorter than that of the prefrontal, and a premaxillary dorsal surface with a median ridge. The holotype skeleton of T. jiufengensis includes a complete axial column with 50 vertebrae (six cervical, 23 dorsal, six sacral, and 15 caudal). Turfanodon represents the first confirmed tetrapod genus shared by the late Permian faunas of the Junggar and Ordos basins, and appears to be the first dicynodont genus distributed across both tropical and temperate zones (based on paleoclimate reconstructions). Based on tetrapod fossil content, the Naobaogou Formation can be roughly correlated to the Daptocephalus Assemblage Zone of South Africa (255-252 Ma in age).
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Affiliation(s)
- Jun Liu
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
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12
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Xie M, Gol'din P, Herdina AN, Estefa J, Medvedeva EV, Li L, Newton PT, Kotova S, Shavkuta B, Saxena A, Shumate LT, Metscher BD, Großschmidt K, Nishimori S, Akovantseva A, Usanova AP, Kurenkova AD, Kumar A, Arregui IL, Tafforeau P, Fried K, Carlström M, Simon A, Gasser C, Kronenberg HM, Bastepe M, Cooper KL, Timashev P, Sanchez S, Adameyko I, Eriksson A, Chagin AS. Secondary ossification center induces and protects growth plate structure. eLife 2020; 9:55212. [PMID: 33063669 PMCID: PMC7581430 DOI: 10.7554/elife.55212] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022] Open
Abstract
Growth plate and articular cartilage constitute a single anatomical entity early in development but later separate into two distinct structures by the secondary ossification center (SOC). The reason for such separation remains unknown. We found that evolutionarily SOC appears in animals conquering the land - amniotes. Analysis of the ossification pattern in mammals with specialized extremities (whales, bats, jerboa) revealed that SOC development correlates with the extent of mechanical loads. Mathematical modeling revealed that SOC reduces mechanical stress within the growth plate. Functional experiments revealed the high vulnerability of hypertrophic chondrocytes to mechanical stress and showed that SOC protects these cells from apoptosis caused by extensive loading. Atomic force microscopy showed that hypertrophic chondrocytes are the least mechanically stiff cells within the growth plate. Altogether, these findings suggest that SOC has evolved to protect the hypertrophic chondrocytes from the high mechanical stress encountered in the terrestrial environment.
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Affiliation(s)
- Meng Xie
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Pavel Gol'din
- Department of Evolutionary Morphology, Schmalhausen Institute of Zoology of NAS of Ukraine, Kiev, Ukraine
| | - Anna Nele Herdina
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Division of Anatomy, MIC, Medical University of Vienna, Vienna, Austria
| | - Jordi Estefa
- Science for Life Laboratory and Uppsala University, Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala, Sweden
| | - Ekaterina V Medvedeva
- Institute for Regenerative Medicine, Sechenov University, Moscow, Russian Federation
| | - Lei Li
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Phillip T Newton
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Women's and Children's Health, Karolinska Institutet and Astrid Lindgren Children's Hospital, Karolinska University Hospital, Solna, Sweden
| | - Svetlana Kotova
- Institute for Regenerative Medicine, Sechenov University, Moscow, Russian Federation.,Semenov Institute of Chemical Physics, Moscow, Russian Federation
| | - Boris Shavkuta
- Institute for Regenerative Medicine, Sechenov University, Moscow, Russian Federation
| | - Aditya Saxena
- Division of Biological Sciences, University of California San Diego, San Diego, United States
| | - Lauren T Shumate
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, United States
| | - Brian D Metscher
- Department of Theoretical Biology, University of Vienna, Vienna, Austria
| | - Karl Großschmidt
- Bone and Biomaterials Research, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Shigeki Nishimori
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, United States
| | - Anastasia Akovantseva
- Institute of Photonic Technologies, Research center "Crystallography and Photonics", Moscow, Russian Federation
| | - Anna P Usanova
- Institute for Regenerative Medicine, Sechenov University, Moscow, Russian Federation
| | | | - Anoop Kumar
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | | | - Paul Tafforeau
- European Synchrotron Radiation Facility, Grenoble, France
| | - Kaj Fried
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Mattias Carlström
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - András Simon
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Christian Gasser
- Department of Solid Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Henry M Kronenberg
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, United States
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, United States
| | - Kimberly L Cooper
- Division of Biological Sciences, University of California San Diego, San Diego, United States
| | - Peter Timashev
- Institute for Regenerative Medicine, Sechenov University, Moscow, Russian Federation.,Semenov Institute of Chemical Physics, Moscow, Russian Federation.,Institute of Photonic Technologies, Research center "Crystallography and Photonics", Moscow, Russian Federation.,Chemistry Department, Lomonosov Moscow State University, Leninskiye Gory 1-3, Moscow, Russian Federation
| | - Sophie Sanchez
- Science for Life Laboratory and Uppsala University, Subdepartment of Evolution and Development, Department of Organismal Biology, Uppsala, Sweden.,European Synchrotron Radiation Facility, Grenoble, France.,Sorbonne Université - CR2P - MNHN, CNRS, UPMC, Paris, France
| | - Igor Adameyko
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Department of Neuroimmunology, Medical University of Vienna, Vienna, Austria
| | - Anders Eriksson
- Department of Mechanics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Andrei S Chagin
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.,Institute for Regenerative Medicine, Sechenov University, Moscow, Russian Federation
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13
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Pusch LC, Ponstein J, Kammerer CF, Fröbisch J. Novel Endocranial Data on the Early Therocephalian Lycosuchus vanderrieti Underpin High Character Variability in Early Theriodont Evolution. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2019.00464] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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14
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de Simão-Oliveira D, Kerber L, L Pinheiro F. Endocranial morphology of the Brazilian Permian dicynodont Rastodon procurvidens (Therapsida: Anomodontia). J Anat 2019; 236:384-397. [PMID: 31670465 DOI: 10.1111/joa.13107] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2019] [Indexed: 12/18/2022] Open
Abstract
Dicynodontia is a major clade of terrestrial tetrapods that greatly diversified during the Permian and Triassic periods, reaching a worldwide distribution. In this study, the endocranial cavity of the Brazilian Permian dicynodont Rastodon procurvidens is described based on a digital endocast obtained using digital imaging (X-ray computed tomography) and 3D modeling. It was possible to reconstruct the brain, olfactory bulbs, inner ear, some neurovascular canals, cranial nerves, the nasal cavity, and the maxillary recesses. The endocast of R. procurvidens preserves a typical plesiomorphic morphology of non-mammaliaform therapsids, being predominantly tubular and displaying a relatively short and robust hindbrain. Encephalization quotients (EQs) were calculated for R. procurvidens, resulting in EQs of 0.09 ± 0.03 and 0.13 ± 0.05 (Jerison's EQ and Manger's EQ, respectively). Finally, some biological implications of the endocast morphology were inferred for R. procurvidens. Its inner ear is especially small, and its orientation implies a slightly downturned head posture in life. Furthermore, the presence of uncompressed maxillary recesses in R. procurvidens indicates a correlation between the enlargement of the recesses and the reduction of the tusks, also seen in other dicynodonts with reduced tusks.
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Affiliation(s)
- Daniel de Simão-Oliveira
- Laboratório de Paleobiologia, Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal do Pampa (Unipampa), São Gabriel, Rio Grande do Sul, Brazil.,Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia (CAPPA), Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria (UFSM), São João do Polêsine, Rio Grande do Sul, Brazil
| | - Leonardo Kerber
- Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia (CAPPA), Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria (UFSM), São João do Polêsine, Rio Grande do Sul, Brazil
| | - Felipe L Pinheiro
- Laboratório de Paleobiologia, Programa de Pós-Graduação em Ciências Biológicas, Universidade Federal do Pampa (Unipampa), São Gabriel, Rio Grande do Sul, Brazil
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15
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Pavanatto AEB, Kerber L, Dias-da-Silva S. Virtual reconstruction of cranial endocasts of traversodontid cynodonts (Eucynodontia: Gomphodontia) from the upper Triassic of Southern Brazil. J Morphol 2019; 280:1267-1281. [PMID: 31241801 DOI: 10.1002/jmor.21029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/03/2019] [Accepted: 06/10/2019] [Indexed: 12/12/2022]
Abstract
The brain endocasts of the late Triassic (Carnian) traversodontids (Eucynodontia: Gomphodontia) Siriusgnathus niemeyerorum and Exaeretodon riograndensis from southern Brazil are described based on virtual models generated using computed tomography scan data. Their skull anatomy resembles that of other non-mammaliaform cynodonts, showing an endocranial cavity that is not fully ossified. A "V-shaped" orbitosphenoid, neither fully developed nor ossified is present in E. riograndensis. The nasal cavity is confluent with the encephalic cavity. Thus, the anterior limit of the olfactory bulbs is not definite. The brain endocast is elongated, being narrow anteriorly and wide posteriorly, with the maximum width at the parafloccular cast. The olfactory bulbs do not present a clear division between their counterparts, due to the absence of a longitudinal sulcus. A longitudinal sulcus in the forebrain delimiting the cerebral hemispheres, the pineal tube, and the parietal foramen are absent in both taxa. The large and well-developed unossified zone is partially separated from the remaining endocast by a notch formed by the supraoccipital. The encephalization quotients, as well as the endocranial volume/body mass relationships of S. niemeyerorum and E. riograndensis are within the range expected for non-mammaliaform Therapsida.
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Affiliation(s)
- Ane E B Pavanatto
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Leonardo Kerber
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil.,Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, São João do Polêsine, Brazil
| | - Sérgio Dias-da-Silva
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil.,Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, São João do Polêsine, Brazil
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16
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Benoit J, Ruf I, Miyamae JA, Fernandez V, Rodrigues PG, Rubidge BS. The Evolution of the Maxillary Canal in Probainognathia (Cynodontia, Synapsida): Reassessment of the Homology of the Infraorbital Foramen in Mammalian Ancestors. J MAMM EVOL 2019. [DOI: 10.1007/s10914-019-09467-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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17
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Pusch LC, Kammerer CF, Fröbisch J. Cranial anatomy of the early cynodont Galesaurus planiceps and the origin of mammalian endocranial characters. J Anat 2019; 234:592-621. [PMID: 30772942 DOI: 10.1111/joa.12958] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2019] [Indexed: 12/19/2022] Open
Abstract
The cranial anatomy of the early non-mammalian cynodont Galesaurus planiceps from the South African Karoo Basin is redescribed on the basis of a computed tomographic reconstruction of the skull. Previously, little was known about internal skull morphology and the nervous and sensory system of this taxon. The endocranial anatomy of various cynodonts has been intensively studied in recent years to understand the origin of mammalian characters in the nasal capsule, brain and ear. However, these studies have focused on only a few taxa, the earliest of which is another Early Triassic cynodont, Thrinaxodon liorhinus. Galesaurus is phylogenetically stemward of Thrinaxodon and thus provides a useful test of whether the mammal-like features observed in Thrinaxodon were present even more basally in cynodont evolution. The cranial anatomy of G. planiceps is characterized by an intriguing mosaic of primitive and derived features within cynodonts. In contrast to the very similar internal nasal and braincase morphology of Galesaurus and Thrinaxodon, parts of the skull that seem to be fairly conservative in non-prozostrodont cynodonts, the morphology of the maxillary canal differs markedly between these taxa. Unusually, the maxillary canal of Galesaurus has relatively few ramifications, more similar to those of probainognathian cynodonts than that of Thrinaxodon. However, its caudal section is very short, a primitive feature shared with gorgonopsians and therocephalians. The otic labyrinth of Galesaurus is generally similar to that of Thrinaxodon, but differs in some notable features (e.g. proportional size of the anterior semicircular canal). An extremely large, protruding paraflocculus of the brain and a distinct medioventrally located notch on the anterior surface of the tabular, which forms the dorsal border of the large parafloccular lobe, are unique to Galesaurus among therapsids with reconstructed endocasts. These features may represent autapomorphies of Galesaurus, but additional sampling is needed at the base of Cynodontia to test this.
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Affiliation(s)
- Luisa C Pusch
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany.,Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Christian F Kammerer
- North Carolina Museum of Natural Sciences, Raleigh, NC, USA.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Jörg Fröbisch
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany.,Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany.,Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
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18
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Bendel EM, Kammerer CF, Kardjilov N, Fernandez V, Fröbisch J. Cranial anatomy of the gorgonopsian Cynariops robustus based on CT-reconstruction. PLoS One 2018; 13:e0207367. [PMID: 30485338 PMCID: PMC6261584 DOI: 10.1371/journal.pone.0207367] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 10/30/2018] [Indexed: 11/19/2022] Open
Abstract
Gorgonopsia is one of the major clades of non-mammalian synapsids, and includes an array of large-bodied carnivores that were the top terrestrial predators of the late Permian. Most research on the clade has focused on these largest members; small-bodied gorgonopsians are relatively little-studied. Here, we redescribe a small gorgonopsian skull (MB.R.999) from the late Permian (Tropidostoma Assemblage Zone) of South Africa on the basis of neutron and synchrotron CT reconstructions, which yield new data on internal cranial morphology in Gorgonopsia. Because of the largely undistorted nature of MB.R.999, we were also able to reconstruct unossified areas such as the brain endocast and the otic labyrinth. MB.R.999 can be referred to the taxon Cynariops robustus based on its general skull proportions, postcanine tooth count, preparietal morphology, and vomerine morphology. We refer additional small gorgonopsian specimens from the Victoria West area to Cynariops robustus, and consider Cynarioides grimbeeki and Cynarioides laticeps to be synonymous with C. robustus. Inclusion of Cynariops in a phylogenetic analysis of Gorgonopsia recovers it within a large clade of African taxa, more closely related to Lycaenops and rubidgeines than Eriphostoma or Gorgonops.
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Affiliation(s)
- Eva-Maria Bendel
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
| | - Christian F. Kammerer
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
- North Carolina Museum of Natural Sciences, Raleigh, NC, United States of America
- Evolutionary Studies Institute & School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Nikolay Kardjilov
- Helmholtz-Zentrum Berlin–Institute of Applied Materials, Berlin, Germany
| | - Vincent Fernandez
- Imaging and Analysis Centre, The Natural History Museum, London, United Kingdom
- European Synchrotron Radiation Facility, Grenoble, France
| | - Jörg Fröbisch
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
- Evolutionary Studies Institute & School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
- Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
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19
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Abstract
The semicircular canal (SC) system of the inner ear detects head angular accelerations and is essential for navigation and spatial awareness in vertebrates. Because the bony labyrinth encloses the membranous labyrinth SCs, it can be used as a proxy for animal behavior. The bony labyrinth of dicynodonts, a clade of herbivorous non-mammalian synapsids, has only been described in a handful of individuals and remains particularly obscure. Here we describe the bony labyrinth anatomy of three Endothiodon cf. bathystoma specimens from Mozambique based on digital reconstructions from propagation phase-contrast synchrotron micro-computed tomography. We compare these findings with the bony labyrinth anatomy of their close relative Niassodon. The bony labyrinths of Endothiodon and Niassodon are relatively similar and show only differences in the shape of the horizontal SCs and the orientation of the vertical SCs. When compared to extant mammals, Endothiodon and Niassodon have highly eccentric SCs. In addition, the Endothiodon SCs are nearly orthogonal. An eccentric and orthogonal SC morphology is consistent with a specialization in rapid head movements, which are typical of foraging or feeding behaviors. Furthermore, we estimate the body mass of these Endothiodon specimens at ~116 to 182 kg, based on the average SC radii calculated using a linear regression model optimized by the Amemiya Prediction Criterion. Our findings provide novel insights into the paleobiology of Endothiodon which are consistent with the peculiar feeding mechanism among dicynodonts presumed from their multiple postcanine toothrows.
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20
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Benoit J, Angielczyk KD, Miyamae JA, Manger P, Fernandez V, Rubidge B. Evolution of facial innervation in anomodont therapsids (Synapsida): Insights from X-ray computerized microtomography. J Morphol 2018; 279:673-701. [PMID: 29464761 DOI: 10.1002/jmor.20804] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 01/29/2018] [Accepted: 02/03/2018] [Indexed: 12/11/2022]
Abstract
Anomodontia was the most successful herbivorous clade of the mammalian stem lineage (non-mammalian synapsids) during the late Permian and Early Triassic. Among anomodonts, Dicynodontia stands apart because of the presence of an osseous beak that shows evidence of the insertion of a cornified sheath, the ramphotheca. In this study, fourteen anomodont specimens were microCT-scanned and their trigeminal canals reconstructed digitally to understand the origin and evolution of trigeminal nerve innervation of the ramphotheca. We show that the pattern of innervation of the anomodont "beak" is more similar to that in chelonians (the nasopalatine branch is enlarged and innervates the premaxillary part of the ramphotheca) than in birds (where the nasopalatine and maxillary branches play minor roles). The nasopalatine branch is noticeably enlarged in the beak-less basal anomodont Patranomodon, suggesting that this could be an anomodont or chainosaur synapomorphy. Our analyses suggest that the presence or absence of tusks and postcanine teeth are often accompanied by corresponding variations of the rami innervating the caniniform process and the alveolar region, respectively. The degree of ossification of the canal for the nasal ramus of the ophthalmic branch also appears to correlate with the presence of a nasal boss. The nasopalatine canal is absent from the premaxilla in the Bidentalia as they uniquely show a large plexus formed by the internal nasal branch of the maxillary canal instead. The elongated shape of this plexus in Lystrosaurus supports the hypothesis that the rostrum evolved as an elongation of the subnarial region of the snout. Finally, the atrophied and variable aspect of the trigeminal canals in Myosaurus supports the hypothesis that this genus had a reduced upper ramphotheca.
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Affiliation(s)
- Julien Benoit
- Evolutionary Studies Institute (ESI), School of Geosciences, University of the Witwatersrand, Johannesburg, 2050, South Africa
| | - Kenneth D Angielczyk
- Evolutionary Studies Institute (ESI), School of Geosciences, University of the Witwatersrand, Johannesburg, 2050, South Africa.,Integrative Research Center, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, Illinois, 60605
| | - Juri A Miyamae
- Department of Geology & Geophysics, P.O. Box 208109, Yale University, New Haven, Connecticut, 06520-8109
| | - Paul Manger
- School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, 2193, South Africa
| | - Vincent Fernandez
- European Synchrotron Radiation Facility, Beamline ID19, Grenoble, 38000, France
| | - Bruce Rubidge
- Evolutionary Studies Institute (ESI), School of Geosciences, University of the Witwatersrand, Johannesburg, 2050, South Africa
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21
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Voeten DFAE, Reich T, Araújo R, Scheyer TM. Synchrotron microtomography of a Nothosaurus marchicus skull informs on nothosaurian physiology and neurosensory adaptations in early Sauropterygia. PLoS One 2018; 13:e0188509. [PMID: 29298295 PMCID: PMC5751976 DOI: 10.1371/journal.pone.0188509] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/08/2017] [Indexed: 02/06/2023] Open
Abstract
Nothosaurs form a subclade of the secondarily marine Sauropterygia that was well represented in late Early to early Late Triassic marine ecosystems. Here we present and discuss the internal skull anatomy of the small piscivorous nothosaur Nothosaurus marchicus from coastal to shallow marine Lower Muschelkalk deposits (Anisian) of Winterswijk, The Netherlands, which represents the oldest sauropterygian endocast visualized to date. The cranial endocast is only partially encapsulated by ossified braincase elements. Cranial flattening and lateral constriction by hypertrophied temporal musculature grant the brain a straight, tubular geometry that lacks particularly well-developed cerebral lobes but does potentially involve distinguishable optic lobes, suggesting vision may have represented an important sense during life. Despite large orbit size, the circuitous muscular pathway linking the basisphenoidal and orbital regions indicates poor oculomotor performance. This suggests a rather fixed ocular orientation, although eye placement and neck manoeuvrability could have enabled binocular if not stereoscopic vision. The proportionally large dorsal projection of the braincase endocast towards the well-developed pineal foramen advocates substantial dependence on the corresponding pineal system in vivo. Structures corroborating keen olfactory or acoustic senses were not identified. The likely atrophied vomeronasal organ argues against the presence of a forked tongue in Nothosaurus, and the relative positioning of external and internal nares contrasts respiratory configurations proposed for pistosauroid sauropterygians. The antorbital domain furthermore accommodates a putative rostral sensory plexus and pronounced lateral nasal glands that were likely exapted as salt glands. Previously proposed nothosaurian 'foramina eustachii' arose from architectural constraints on braincase development rather than representing functional foramina. Several modifications to brain shape and accessory organs were achieved through heterochronic development of the cranium, particularly the braincase. In summary, the cranium of Nothosaurus marchicus reflects important physiological and neurosensory adaptations that enabled the group's explosive invasion of shallow marine habitats in the late Early Triassic.
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Affiliation(s)
- Dennis F. A. E. Voeten
- European Synchrotron Radiation Facility, Grenoble, France
- Department of Zoology and Laboratory of Ornithology, Palacký University, Olomouc, Czech Republic
| | - Tobias Reich
- University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland
| | - Ricardo Araújo
- Institute for Plasma Research and Nuclear Fusion, Technical University of Lisbon, Lisbon, Portugal
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
- Institute of Evolutionary Sciences, University of Montpellier 2, Montpellier, France
| | - Torsten M. Scheyer
- University of Zurich, Palaeontological Institute and Museum, Zurich, Switzerland
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22
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Benoit J, Manger PR, Norton L, Fernandez V, Rubidge BS. Synchrotron scanning reveals the palaeoneurology of the head-butting Moschops capensis (Therapsida, Dinocephalia). PeerJ 2017; 5:e3496. [PMID: 28828230 PMCID: PMC5554600 DOI: 10.7717/peerj.3496] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 06/02/2017] [Indexed: 12/17/2022] Open
Abstract
Dinocephalian therapsids are renowned for their massive, pachyostotic and ornamented skulls adapted for head-to-head fighting during intraspecific combat. Synchrotron scanning of the tapinocephalid Moschops capensis reveals, for the first time, numerous anatomical adaptations of the central nervous system related to this combative behaviour. Many neural structures (such as the brain, inner ear and ophthalmic branch of the trigeminal nerve) were completely enclosed and protected by bones, which is unusual for non-mammaliaform therapsids. The nearly complete ossification of the braincase enables precise determination of the brain cavity volume and encephalization quotient, which appears greater than expected for such a large and early herbivore. The practice of head butting is often associated with complex social behaviours and gregariousness in extant species, which are known to influence brain size evolution. Additionally, the plane of the lateral (horizontal) semicircular canal of the bony labyrinth is oriented nearly vertically if the skull is held horizontally, which suggests that the natural position of the head was inclined about 60–65°to the horizontal. This is consistent with the fighting position inferred from osteology, as well as ground-level browsing. Finally, the unusually large parietal tube may have been filled with thick conjunctive tissue to protect the delicate pineal eye from injury sustained during head butting.
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Affiliation(s)
- Julien Benoit
- Evolutionary Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa.,School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Paul R Manger
- School of Anatomical Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Luke Norton
- Evolutionary Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Vincent Fernandez
- Beamline ID19, European Synchrotron Radiation Facility, Grenoble, France
| | - Bruce S Rubidge
- Evolutionary Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
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23
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Benoit J, Jasinoski SC, Fernandez V, Abdala F. The mystery of a missing bone: revealing the orbitosphenoid in basal Epicynodontia (Cynodontia, Therapsida) through computed tomography. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2017; 104:66. [PMID: 28721557 DOI: 10.1007/s00114-017-1487-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 04/12/2017] [Accepted: 06/29/2017] [Indexed: 11/26/2022]
Abstract
The basal non-mammaliaform cynodonts from the late Permian (Lopingian) and Early Triassic are a major source of information for the understanding of the evolutionary origin of mammals. Detailed knowledge of their anatomy is critical for understanding the phylogenetic transition toward mammalness and the paleobiological reconstruction of mammalian precursors. Using micro-computed tomography (μCT), we describe the internal morphology of the interorbital region that includes the rarely fossilized orbitosphenoid elements in four basal cynodonts. These paired bones, which are positioned relatively dorsally in the skull, contribute to the wall of the anterior part of the braincase and form the floor for the olfactory lobes. Unlike procynosuchids and the more basal therapsids in which the orbitosphenoids are well developed, dense, and bear a ventral keel, the basal epicynodonts Cynosaurus, Galesaurus, and Thrinaxodon display cancellous, reduced, and loosely articulated orbitosphenoids, a condition shared with many eucynodonts. The hemi-cylindrical orbitosphenoid from which the mammalian condition is derived re-evolved convergently in traversodontid and some probainognathian cynodonts.
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Affiliation(s)
- Julien Benoit
- Evolutionary Studies Institute; School of Geosciences, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg, 2050, South Africa.
- School of Anatomical Sciences, University of the Witwatersrand, 7 York Road, Johannesburg, 2193, South Africa.
| | - Sandra C Jasinoski
- Evolutionary Studies Institute; School of Geosciences, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg, 2050, South Africa
| | - Vincent Fernandez
- European Synchrotron Radiation Facility, 71 rue des Martyrs, 38000, Grenoble, France
| | - Fernando Abdala
- Evolutionary Studies Institute; School of Geosciences, University of the Witwatersrand, Private Bag 3, WITS, Johannesburg, 2050, South Africa
- Unidad Ejecutora Lillo CONICET, Miguel Lillo, 251, Tucumán, Argentina
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24
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Laaß M, Schillinger B, Kaestner A. What did the "Unossified zone" of the non-mammalian therapsid braincase house? J Morphol 2017. [PMID: 28621458 DOI: 10.1002/jmor.20583] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Most nonmammalian synapsids possess a mid-dorsal depression in the brain cavity known as the "unossified zone." It remains obscure which structures this zone contained, and, as candidates, the vermis of the cerebellum, the superior sagittal sinus, a junction of several blood vessels, the pineal gland or other midbrain structures were considered. Neutron tomography of a skull of Diictodon feliceps (Therapsida, Anomodontia) revealed some clear impressions of canals in this region of the brain cavity. Furthermore, the prootic sinus probably ran on the internal surface of the pila antotica and had a similar course in anomodonts as it has been proposed for cynodonts and Mesozoic mammals. Comparisons with the vascular systems of nonmammalian synapsids and mammals suggest that the unossified zone is best interpreted as a terminal chamber of the anterior segment of the medial head vein, which housed the junction of the superior sagittal sinus and the transverse sinuses. Consequently, the system of cranial vessels in Diictodon reveals a partial division of the medial head vein system into an anterior and a posterior segment at an early stage of synapsid evolution, which is consistent with the well-known common pattern of early ontogenetic development in amniotes. J. Morphol., 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Michael Laaß
- Faculty of Biology, Department of General Zoology, University of Duisburg-Essen, Universitätsstr. 5, Essen, D-45117, Germany
| | - Burkhard Schillinger
- Heinz Maier-Leibnitz Centre and Faculty for Physics E21, Technische Universität München, Lichtenbergstraße 1, Garching, D-85747, Germany
| | - Anders Kaestner
- Neutron Imaging and Activation Group, Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen, PSI, CH-5232, Switzerland
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Laaß M, Kaestner A. Evidence for convergent evolution of a neocortex-like structure in a late Permian therapsid. J Morphol 2017. [PMID: 28621462 DOI: 10.1002/jmor.20712] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The special sensory, motor, and cognitive capabilities of mammals mainly depend upon the neocortex, which is the six-layered cover of the mammalian forebrain. The origin of the neocortex is still controversial and the current view is that larger brains with neocortex first evolved in late Triassic Mammaliaformes. Here, we report the earliest evidence of a structure analogous to the mammalian neocortex in a forerunner of mammals, the fossorial anomodont Kawingasaurus fossilis from the late Permian of Tanzania. The endocranial cavity of Kawingasaurus is almost completely ossified, which allowed a less hypothetical virtual reconstruction of the brain endocast to be generated. A parietal foramen is absent. A small pit between the cerebral hemispheres is interpreted as a pineal body. The inflated cerebral hemispheres are demarcated from each other by a median sulcus and by a possible rhinal fissure from the rest of the endocast. The encephalization quotient estimated by using the method of Eisenberg is 0.52, which is 2-3 times larger than in other nonmammalian synapsids. Another remarkable feature are the extremely ramified infraorbital canals in the snout. The shape of the brain endocast, the extremely ramified maxillary canals as well as the small frontally placed eyes suggest that special sensory adaptations to the subterranean habitat such as a well developed sense of touch and binocular vision may have driven the parallel evolution of an equivalent of the mammalian neocortex and a mammal-like lemnothalamic visual system in Kawingasaurus. The gross anatomy of the brain endocast of Kawingasaurus supports the Outgroup Hypothesis, according to which the neocortex evolved from the dorsal pallium of an amphibian-like ancestor, which receives sensory projections from the lemnothalamic pathway. The enlarged brain as well as the absence of a parietal foramen may be an indication for a higher metabolic rate of Kawingasaurus compared to other nonmammalian synapsids.
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Affiliation(s)
- Michael Laaß
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 2, Essen, D-45117, Germany
| | - Anders Kaestner
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, Villigen PSI, CH-5232, Switzerland
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Floccular fossa size is not a reliable proxy of ecology and behaviour in vertebrates. Sci Rep 2017; 7:2005. [PMID: 28515458 PMCID: PMC5435717 DOI: 10.1038/s41598-017-01981-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 03/30/2017] [Indexed: 11/10/2022] Open
Abstract
The cerebellar floccular and parafloccular lobes are housed in fossae of the periotic region of the skull of different vertebrates. Experimental evidence indicates that the lobes integrate visual and vestibular information and control the vestibulo-ocular reflex, vestibulo-collic reflex, smooth pursuit and gaze holding. Multiple paleoneuroanatomy studies have deduced the behaviour of fossil vertebrates by measuring the floccular fossae (FF). These studies assumed that there are correlations between FF volume and behaviour. However, these assumptions have not been fully tested. Here, we used micro-CT scans of extant mammals (47 species) and birds (59 species) to test six possible morphological-functional associations between FF volume and ecological/behavioural traits of extant animals. Behaviour and ecology do not explain FF volume variability in four out of six variables tested. Two variables with significant results require further empirical testing. Cerebellum plasticity may explain the lack of statistical evidence for the hypotheses tested. Therefore, variation in FF volume seems to be better explained by a combination of factors such as anatomical and phylogenetic evolutionary constraints, and further empirical testing is required.
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Araújo R, Fernandez V, Polcyn MJ, Fröbisch J, Martins RMS. Aspects of gorgonopsian paleobiology and evolution: insights from the basicranium, occiput, osseous labyrinth, vasculature, and neuroanatomy. PeerJ 2017; 5:e3119. [PMID: 28413721 PMCID: PMC5390774 DOI: 10.7717/peerj.3119] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 02/23/2017] [Indexed: 12/14/2022] Open
Abstract
Synapsida, the clade including therapsids and thus also mammals, is one of the two major branches of amniotes. Organismal design, with modularity as a concept, offers insights into the evolution of therapsids, a group that experienced profound anatomical transformations throughout the past 270 Ma, eventually leading to the evolution of the mammalian bauplan. However, the anatomy of some therapsid groups remains obscure. Gorgonopsian braincase anatomy is poorly known and many anatomical aspects of the brain, cranial nerves, vasculature, and osseous labyrinth, remain unclear. We analyzed two gorgonopsian specimens, GPIT/RE/7124 and GPIT/RE/7119, using propagation phase contrast synchrotron micro-computed tomography. The lack of fusion between many basicranial and occipital bones in GPIT/RE/7124, which is an immature specimen, allowed us to reconstruct its anatomy and ontogenetic sequence, in comparison with the mature GPIT/RE/7119, in great detail. We explored the braincase and rendered various skull cavities. Notably, we found that there is a separate ossification between what was previously referred to as the “parasphenoid” and the basioccipital. We reinterpreted this element as a posterior ossification of the basisphenoid: the basipostsphenoid. Moreover, we show that the previously called “parasphenoid” is in fact the co-ossification of the dermal parasphenoid and the endochondral basipresphenoid. In line with previous descriptions, the anatomy of the osseous labyrinth is rendered in detail, revealing a unique discoid morphology of the horizontal semicircular canal, rather than toroidal, probably due to architectural constraints of the ossification of the opisthotic and supraoccipital. In addition, the orientation of the horizontal semicircular canal suggests that gorgonopsians had an anteriorly tilted alert head posture. The morphology of the brain endocast is in accordance with the more reptilian endocast shape of other non-mammaliaform neotherapsids.
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Affiliation(s)
- Ricardo Araújo
- Instituto Superior Técnico, Instituto de Plasmas e Fusão Nuclear, Universidade de Lisboa, Lisboa, Portugal.,Museum für Naturkunde, Leibniz-Institut für Evolutions-und Biodiversitätsforschung, Berlin, Germany.,Huffington Department of Earth Sciences, Southern Methodist Univesity, Dallas, TX, United States of America.,GEAL-Museu da Lourinhã, Lourinhã, Portugal.,Institut des Sciences de l'Evolution, Université de Montpellier 2, Montpellier, France
| | | | - Michael J Polcyn
- Huffington Department of Earth Sciences, Southern Methodist Univesity, Dallas, TX, United States of America
| | - Jörg Fröbisch
- Museum für Naturkunde, Leibniz-Institut für Evolutions-und Biodiversitätsforschung, Berlin, Germany.,Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Rui M S Martins
- Instituto Superior Técnico, Instituto de Plasmas e Fusão Nuclear, Universidade de Lisboa, Lisboa, Portugal.,CENIMAT/I3N, Universidade Nova de Lisboa, Monte de Caparica, Portugal.,GEAL-Museu da Lourinhã, Lourinhã, Portugal
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Kammerer CF, Smith RMH. An early geikiid dicynodont from the Tropidostoma Assemblage Zone (late Permian) of South Africa. PeerJ 2017; 5:e2913. [PMID: 28168104 PMCID: PMC5289114 DOI: 10.7717/peerj.2913] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 12/14/2016] [Indexed: 11/20/2022] Open
Abstract
Based on specimens previously identified as Tropidostoma, a new taxon of dicynodont (Bulbasaurus phylloxyron gen. et sp. nov.) from the Karoo Basin of South Africa is described. Bulbasaurus is a medium-sized dicynodont (maximum dorsal skull length 16.0 cm) restricted to the Tropidostoma Assemblage Zone (early Lopingian) of the Beaufort Group. Bulbasaurus can be distinguished from Tropidostoma by an array of characters including the presence of a tall, sharp premaxillary ridge, large, rugose, nearly-confluent nasal bosses, a nasofrontal ridge, massive tusks, robust pterygoids, prominently twisted subtemporal bar, and absence of a distinct postfrontal. Inclusion of Bulbasaurus in a phylogenetic analysis of anomodont therapsids recovers it as a member of Geikiidae, a clade of otherwise later Permian dicynodonts such as Aulacephalodon and Pelanomodon. Bulbasaurus exhibits many of the characters typical of adult Aulacephalodon, but at substantially smaller skull size (these characters are absent in comparably-sized Aulacephalodon juveniles), suggesting that the evolution of typical geikiid morphology preceded gigantism in the clade. Bulbasaurus is the earliest known geikiid and the only member of the group known from the Tropidostoma Assemblage Zone; discovery of this taxon shortens a perplexing ghost lineage and indicates that abundant clades from the later Permian of South Africa (e.g., Geikiidae, Dicynodontoidea) may have originated as rare components of earlier Karoo assemblage zones.
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Affiliation(s)
- Christian F Kammerer
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany; Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Roger M H Smith
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa; Iziko Museums of South Africa, Cape Town, South Africa
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Kogure T, Yamaguchi N, Segawa H, Mukai H, Motai S, Akiyama-Hasegawa K, Mitome M, Hara T, Yaita T. Constituent elements and their distribution in the radioactive Cs-bearing silicate glass microparticles released from Fukushima nuclear plant. Microscopy (Oxf) 2016; 65:451-459. [DOI: 10.1093/jmicro/dfw030] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/06/2016] [Indexed: 11/12/2022] Open
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Atkins JB, Franz-Odendaal TA. The sclerotic ring of squamates: an evo-devo-eco perspective. J Anat 2016; 229:503-13. [PMID: 27240556 DOI: 10.1111/joa.12498] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2016] [Indexed: 11/28/2022] Open
Abstract
The sclerotic ring consists of several bones that form in the sclera of many reptiles. This element has not been well studied in squamates, a diverse order of reptiles with a rich fossil record but debated phylogeny. Squamates inhabit many environments, display a range of behaviours, and have evolved several different body plans. Most importantly, many species have secondarily lost their sclerotic rings. This research investigates the presence of sclerotic rings in squamates and traces the lineage of these bones across evolutionary time. We compiled a database on the presence/absence of the sclerotic ring in extinct and extant squamates and investigated the evolutionary history of the sclerotic ring and how its presence/absence and morphology is correlated with environment and behaviour within this clade. Of the 400 extant species examined (59 families, 214 genera), 69% have a sclerotic ring. Those species that do not are within Serpentes, Amphisbaenia, and Dibamidae. We find that three independent losses of the sclerotic ring in squamates are supported when considering both evolutionary and developmental evidence. We also show that squamate species that lack, or have a reduced, sclerotic ring, are fossorial and headfirst burrowers. Our dataset is the largest squamate dataset with measurements of sclerotic rings, and supports previous findings that size of the ring is related to both environment occupied and behaviour. Specifically, scotopic species tend to have both larger inner and outer sclerotic ring apertures, resulting in a narrower ring of bone than those found in photopic species. Non-fossorial species also have a larger sclerotic ring than fossorial species. This research expands our knowledge of these fascinating bones; with further phylogenetic analyses scleral ossicles could become an extremely useful character trait for inferring the behaviour of fossil squamates.
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Godoy PL, Bronzati M, Eltink E, Marsola JCDA, Cidade GM, Langer MC, Montefeltro FC. Postcranial anatomy of Pissarrachampsa sera (Crocodyliformes, Baurusuchidae) from the Late Cretaceous of Brazil: insights on lifestyle and phylogenetic significance. PeerJ 2016; 4:e2075. [PMID: 27257551 PMCID: PMC4888301 DOI: 10.7717/peerj.2075] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/03/2016] [Indexed: 11/20/2022] Open
Abstract
The postcranial anatomy of Crocodyliformes has historically been neglected, as most descriptions are based solely on skulls. Yet, the significance of the postcranium in crocodyliforms evolution is reflected in the great lifestyle diversity exhibited by the group, with members ranging from terrestrial animals to semi-aquatic and fully marine forms. Recently, studies have emphasized the importance of the postcranium. Following this trend, here we present a detailed description of the postcranial elements of Pissarrachampsa sera (Mesoeucrocodylia, Baurusuchidae), from the Adamantina Formation (Bauru Group, Late Cretaceous of Brazil). The preserved elements include dorsal vertebrae, partial forelimb, pelvic girdle, and hindlimbs. Comparisons with the postcranial anatomy of baurusuchids and other crocodyliforms, together with body-size and mass estimates, lead to a better understanding of the paleobiology of Pissarrachampsa sera, including its terrestrial lifestyle and its role as a top predator. Furthermore, the complete absence of osteoderms in P. sera, a condition previously known only in marine crocodyliforms, suggests osteoderms very likely played a minor role in locomotion of baurusuchids, unlike other groups of terrestrial crocodyliforms. Finally, a phylogenetic analysis including the newly recognized postcranial features was carried out, and exploratory analyses were performed to investigate the influence of both cranial and postcranial characters in the phylogeny of Crocodyliformes. Our results suggest that crocodyliform relationships are mainly determined by cranial characters. However, this seems to be a consequence of the great number of missing entries in the data set with only postcranial characters and not of the lack of potential (or synapomorphies) for this kind of data to reflect the evolutionary history of Crocodyliformes.
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Affiliation(s)
- Pedro L. Godoy
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Mario Bronzati
- Bayerische Staatssammlung für Paläontologie und Geologie, Staatlichen Naturwissenschaftlichen Sammlungen Bayerns, Munich, Germany
- Department of Earth and Environmental Sciences, Palaeontology & Geobiology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Estevan Eltink
- Laboratório de Paleontologia de Ribeirão Preto, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Júlio C. de A. Marsola
- Laboratório de Paleontologia de Ribeirão Preto, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Giovanne M. Cidade
- Laboratório de Paleontologia de Ribeirão Preto, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Max C. Langer
- Laboratório de Paleontologia de Ribeirão Preto, FFCLRP, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Felipe C. Montefeltro
- Departamento de Biologia e Zootecnia, Universidade Estadual Paulista (UNESP), Ilha Solteira, Brazil
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Boos ADS, Kammerer CF, Schultz CL, Soares MB, Ilha ALR. A New Dicynodont (Therapsida: Anomodontia) from the Permian of Southern Brazil and Its Implications for Bidentalian Origins. PLoS One 2016; 11:e0155000. [PMID: 27224287 PMCID: PMC4880204 DOI: 10.1371/journal.pone.0155000] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 04/22/2016] [Indexed: 01/17/2023] Open
Abstract
Dicynodonts were a highly successful group of herbivorous therapsids that inhabited terrestrial ecosystems from the Middle Permian through the end of the Triassic periods. Permian dicynodonts are extremely abundant in African deposits, but are comparatively poorly known from the other regions of Gondwana. Here we describe a new South American dicynodont, Rastodon procurvidens gen. et sp. nov., from the Boqueirão farm site of the Rio do Rasto Formation, Paraná Basin, Guadalupian/Lopingian of Brazil. Diagnostic features of R. procurvidens include uniquely anteriorly-curved maxillary tusks, well-developed ridges extending from the crista oesophagea anteriorly along the pterygoid rami, strong posterior angulation of the posterior pterygoid rami, and a bulbous, well-developed retroarticular process of the articular. Phylogenetic analysis indicates that R. procurvidens is the earliest and most basal member of Bidentalia, a cosmopolitan clade that includes Permian and Triassic dicynodonts whose dentition is usually reduced to a pair of maxillary tusks.
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Affiliation(s)
- Alessandra D. S. Boos
- Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
- Departamento de Ciências Naturais, Fundação Universidade Regional de Blumenau, Blumenau, Santa Catarina, Brazil
- * E-mail:
| | - Christian F. Kammerer
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin, Germany
| | - Cesar L. Schultz
- Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Marina B. Soares
- Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Ana L. R. Ilha
- Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
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Oliveira NC, Silva JH, Barros OA, Pinheiro AP, Santana W, Saraiva AAF, Ferreira OP, Freire PTC, Paula AJ. Large-Field Electron Imaging and X-ray Elemental Mapping Unveil the Morphology, Structure, and Fractal Features of a Cretaceous Fossil at the Centimeter Scale. Anal Chem 2015; 87:10088-95. [DOI: 10.1021/acs.analchem.5b02815] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Naiara C. Oliveira
- Solid-Biological
Interface Group (SolBIN), Departamento de Física, Universidade Federal do Ceará, P.O. Box 6030, 60455-900 Fortaleza, Ceará, Brazil
| | - João H. Silva
- Universidade Federal do Cariri, Cidade Universitária, 63048-080 Juazeiro do Norte, Ceará, Brazil
| | | | | | - William Santana
- Sistematic
Zoology Laboratory (LSZ), Pró-Reitoria de Pesquisa e Pós-Graduação, Universidade Sagrado Coração (USC), 17011-160 Bauru, São Paulo, Brazil
| | | | | | | | - Amauri J. Paula
- Solid-Biological
Interface Group (SolBIN), Departamento de Física, Universidade Federal do Ceará, P.O. Box 6030, 60455-900 Fortaleza, Ceará, Brazil
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Cisneros JC, Abdala F, Jashashvili T, de Oliveira Bueno A, Dentzien-Dias P. Tiarajudens eccentricus and Anomocephalus africanus, two bizarre anomodonts (Synapsida, Therapsida) with dental occlusion from the Permian of Gondwana. ROYAL SOCIETY OPEN SCIENCE 2015; 2:150090. [PMID: 26587266 PMCID: PMC4632579 DOI: 10.1098/rsos.150090] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Accepted: 06/16/2015] [Indexed: 06/05/2023]
Abstract
Anomodontia was a highly successful tetrapod clade during the Permian and the Triassic. New morphological information regarding two bizarre basal anomodonts is provided and their palaeoecological significance is explored. The osteology of the recently discovered Tiarajudens eccentricus Cisneros et al. 2011, from the Brazilian Permian, is described in detail. The taxon exhibits unusual postcranial features, including the presence of gastralia. Additional preparation and computed tomography scans of the holotype of Anomocephalus africanus Modesto et al. 1999 discovered in the Karoo Basin of South Africa allow a reappraisal of this genus. Anomocephalus is similar to Tiarajudens with regard to several traits, including a battery of large, transversally expanded, palatal teeth. Molariform teeth are present in the mandible of the African taxon, providing additional insight into the function of the earliest tooth-occlusion mechanism known in therapsids. At least two waves of tooth replacement can be recognized in the palate of Anomocephalus. The outsized, blade-like caniniforms of the herbivorous Tiarajudens allow several non-exclusive ecological interpretations, among which we favour intraspecific display or combat. This behaviour was an alternative to the head-butting practised by the contemporary dinocephalians. Combat specializations that are considered typical of Cenozoic herbivores likely evolved during the Middle Permian, at the time the first communities with diverse, abundant tetrapod herbivores were being assembled.
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Affiliation(s)
| | - Fernando Abdala
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Tea Jashashvili
- Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Ana de Oliveira Bueno
- Departamento de Paleontologia e Estratigrafia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Paula Dentzien-Dias
- Laboratório de Paleontologia e Paleoceanografia, Universidade Federal do Rio Grande, Rio Grande, Brazil
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Abstract
Conventional wisdom holds that the avian respiratory system is unique because air flows in the same direction through most of the gas-exchange tubules during both phases of ventilation. However, recent studies showing that unidirectional airflow also exists in crocodilians and lizards raise questions about the true phylogenetic distribution of unidirectional airflow, the selective drivers of the trait, the date of origin, and the functional consequences of this phenomenon. These discoveries suggest unidirectional flow was present in the common diapsid ancestor and are inconsistent with the traditional paradigm that unidirectional flow is an adaptation for supporting high rates of gas exchange. Instead, these discoveries suggest it may serve functions such as decreasing the work of breathing, decreasing evaporative respiratory water loss, reducing rates of heat loss, and facilitating crypsis. The divergence in the design of the respiratory system between unidirectionally ventilated lungs and tidally ventilated lungs, such as those found in mammals, is very old, with a minimum date for the divergence in the Permian Period. From this foundation, the avian and mammalian lineages evolved very different respiratory systems. I suggest the difference in design is due to the same selective pressure, expanded aerobic capacity, acting under different environmental conditions. High levels of atmospheric oxygen of the Permian Period relaxed selection for a thin blood-gas barrier and may have resulted in the homogeneous, broncho-alveolar design, whereas the reduced oxygen of the Mesozoic selected for a heterogeneous lung with an extremely thin blood-gas barrier. These differences in lung design may explain the puzzling pattern of ecomorphological diversification of Mesozoic mammals: all were small animals that did not occupy niches requiring a great aerobic capacity. The broncho-alveolar lung and the hypoxia of the Mesozoic may have restricted these mammals from exploiting niches of large body size, where cursorial locomotion can be advantageous, as well as other niches requiring great aerobic capacities, such as those using flapping flight. Furthermore, hypoxia may have exerted positive selection for a parasagittal posture, the diaphragm, and reduced erythrocyte size, innovations that enabled increased rates of ventilation and more rapid rates of diffusion in the lung.
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Laaß M. Virtual reconstruction and description of the cranial endocast of Pristerodon mackayi (Therapsida, Anomodontia). J Morphol 2015; 276:1089-99. [PMID: 26129638 DOI: 10.1002/jmor.20397] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/02/2015] [Accepted: 04/25/2015] [Indexed: 11/06/2022]
Abstract
The cranial endocast of Pristerodon mackayi is described, which has been virtually reconstructed on the basis of neutron tomographic data. The gross anatomy of the cranial endocast of Pristerodon resembles other nonmammalian synapsids such as Thrinaxodon liorhinus in having a narrow, tubular forebrain, well developed olfactory bulbs, a large parietal foramen and unossified zone. As it is the case in cynodonts the hindbrain of Pristerodon is broader than the mid- and forebrain. Large paraflocculi are developed. The medulla oblongata can be well distinguished from the pons. The pons is divided by a median ridge into two portions. There is no evidence for a neocortex, which seems to be also reflected in the low encephalization quotient of 0.18 estimated according to the method of Eisenberg.
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Affiliation(s)
- Michael Laaß
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Duisburg-Essen, Germany
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Laaß M, Schillinger B. Reconstructing the Auditory Apparatus of Therapsids by Means of Neutron Tomography. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.phpro.2015.07.089] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Laaß M. Bone-conduction hearing and seismic sensitivity of the Late Permian anomodont Kawingasaurus fossilis. J Morphol 2014; 276:121-43. [PMID: 25284624 DOI: 10.1002/jmor.20325] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 07/23/2014] [Accepted: 08/09/2014] [Indexed: 11/11/2022]
Abstract
An investigation of the internal cranial anatomy of the anomodont Kawingasaurus from the Upper Permian Usili Formation in Tanzania by means of neutron tomography revealed an unusual inner and middle ear anatomy such as extraordinarily inflated vestibules, lateroventrally orientated stapes with large footplates, and a small angle between the planes of the anterior and lateral semicircular canals. The vestibule has a volume, which is about 25 times larger than the human vestibule, although Kawingasaurus has only a skull length of approximately 40 mm. Vestibule inflation and enlarged stapes footplates are thought to be functionally correlated with bone-conduction hearing; both morphologies have been observed in fossorial vertebrates using seismic signals for communication. The firmly fused triangular head with spatulate snout was probably used for digging and preadapted to seismic signal detection. The quadrate-quadratojugal complex was able to transmit sound from the articular to the stapes by small vibrations of the quadrate process, which formed a ball and socket joint with the squamosal. Mechanical considerations suggest that the ventrolaterally orientated stapes of Kawingasaurus was mechanically better suited to transmit seismic sound from the ground to the fenestra vestibuli than a horizontal orientated stapes. The low sound pressure level transformer ratio of 2-3 in Kawingasaurus points to a seismic sensitivity of the middle ear and a vestigial or reduced sensitivity to airborne sound. Three hypothetical pathways of bone conduction in Kawingasaurus are discussed: 1) sound transmission via the spatulate snout and skull roof to the otic capsules, 2) relative movements resulting from the inertia of the mandible if sound is percepted with the skull, and 3) bone conduction from the substrate via mandible, jaw articulation, and stapes to the inner ear.
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Affiliation(s)
- Michael Laaß
- Institute of Earth Sciences, Ruprecht-Karls-University of Heidelberg, Im Neuenheimer Feld 234, D-69120, Heidelberg, Germany
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