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Bertrand OC, Jiménez Lao M, Shelley SL, Wible JR, Williamson TE, Meng J, Brusatte SL. The virtual brain endocast of Trogosus (Mammalia, Tillodontia) and its relevance in understanding the extinction of archaic placental mammals. J Anat 2024; 244:1-21. [PMID: 37720992 PMCID: PMC10734658 DOI: 10.1111/joa.13951] [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: 06/10/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/19/2023] Open
Abstract
After successfully diversifying during the Paleocene, the descendants of the first wave of mammals that survived the end-Cretaceous mass extinction waned throughout the Eocene. Competition with modern crown clades and intense climate fluctuations may have been part of the factors leading to the extinction of these archaic groups. Why these taxa went extinct has rarely been studied from the perspective of the nervous system. Here, we describe the first virtual endocasts for the archaic order Tillodontia. Three species from the middle Eocene of North America were analyzed: Trogosus hillsii, Trogosus grangeri, and Trogosus castoridens. We made morphological comparisons with the plaster endocast of another tillodont, Tillodon fodiens, as well as groups potentially related to Tillodontia: Pantodonta, Arctocyonidae, and Cimolesta. Trogosus shows very little inter-specific variation with the only potential difference being related to the fusion of the optic canal and sphenorbital fissure. Many ancestral features are displayed by Trogosus, including an exposed midbrain, small neocortex, orbitotemporal canal ventral to rhinal fissure, and a broad circular fissure. Potential characteristics that could unite Tillodontia with Pantodonta, and Arctocyonidae are the posterior position of cranial nerve V3 exit in relation to the cerebrum and the low degree of development of the subarcuate fossa. The presence of large olfactory bulbs and a relatively small neocortex are consistent with a terrestrial lifestyle. A relatively small neocortex may have put Trogosus at risk when competing with artiodactyls for potentially similar resources and avoiding predation from archaic carnivorans, both of which are known to have had larger relative brain and neocortex sizes in the Eocene. These factors may have possibly exacerbated the extinction of Tillodontia, which showed highly specialized morphologies despite the increase in climate fluctuations throughout the Eocene, before disappearing during the middle Eocene.
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Affiliation(s)
- Ornella C Bertrand
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, Cerdanyola del Vallès, Barcelona, Spain
- School of GeoSciences, Grant Institute, University of Edinburgh, Edinburgh, Scotland, UK
| | - Marina Jiménez Lao
- School of GeoSciences, Grant Institute, University of Edinburgh, Edinburgh, Scotland, UK
| | - Sarah L Shelley
- School of GeoSciences, Grant Institute, University of Edinburgh, Edinburgh, Scotland, UK
- Section of Mammals, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA
| | - John R Wible
- Section of Mammals, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA
| | - Thomas E Williamson
- New Mexico Museum of Natural History and Science, Albuquerque, New Mexico, USA
| | - Jin Meng
- Division of Paleontology, American Museum of Natural History, New York, New York, USA
| | - Stephen L Brusatte
- School of GeoSciences, Grant Institute, University of Edinburgh, Edinburgh, Scotland, UK
- New Mexico Museum of Natural History and Science, Albuquerque, New Mexico, USA
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Fostowicz-Frelik Ł, Cox PG, Li Q. Mandibular characteristics of early Glires (Mammalia) reveal mixed rodent and lagomorph morphotypes. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220087. [PMID: 37183896 PMCID: PMC10184241 DOI: 10.1098/rstb.2022.0087] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
Glires (rodents, lagomorphs and their fossil kin) is the most speciose and arguably most diversified clade of living placentals. Different lineages within the Glires evolved basically opposite chewing movements: a mostly transversal power stroke in lagomorphs, and a mostly proal power stroke in rodents, but the ancestral condition for Glires is still unclear. To address this knowledge gap, we studied the mandibles of Chinese Palaeocene Glires representing the duplicidentate (lagomorph-like; Mimotona) and simplicidentate (rodent-like; Eomylus and Heomys) lineages. To assess the mechanical resistance of mandibles to bending and torsion, we calculated the section modulus. The dentaries differ greatly in morphology and the region where the maximum grinding force was likely applied. The early Palaeocene Mimotona lii and the middle Palaeocene Mimotona robusta and Heomys orientalis all show a pattern of increasing strength moving posteriorly along the mandible, similar to sciurids and the mountain beaver. By contrast, the late Palaeocene Eomylus sp. mandible was strongest in the m1 region, a pattern seen in lagomorphs and the stem placental Zofialestes. Our results indicate the early diversification of mandible structure of Glires, demonstrate a mixture of duplicidentate and simplicidentate characters among the basal Glires and suggest an early occurrence of a lagomorph-like morphotype. This article is part of the theme issue 'The mammalian skull: development, structure and function'.
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Affiliation(s)
- Łucja Fostowicz-Frelik
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
- Institute of Paleobiology, Polish Academy of Sciences, 00-818 Warsaw, Poland
| | - Philip G Cox
- Centre for Integrative Anatomy, Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Qian Li
- Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, People's Republic of China
- Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Beijing 100044, People's Republic of China
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Ruf I, Meng J, Fostowicz-Frelik Ł. Auditory region circulation in Lagomorpha: the internal carotid artery pattern revisited. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220088. [PMID: 37183894 PMCID: PMC10184246 DOI: 10.1098/rstb.2022.0088] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
The internal carotid artery (ICA) is one of the major vessels in the cranial circulation. Characters concerning the ICA, such as its course in the auditory region, have been employed frequently in phylogenetic analyses of mammals, including extinct taxa. In lagomorphs, however, our knowledge on vascular features of the auditory region has been based predominantly on living species, mostly on the European rabbit. We present the first survey on 11 out of 12 extant genera and key fossil taxa such as stem lagomorphs and early crown representatives (Archaeolagus and Prolagus). The ICA pattern shows a modified transpromontorial course in stem taxa (Litolagus, Megalagus and Palaeolagus) and Archaeolagus, which we propose as the ancestral character state for Lagomorpha, similar to that for the earliest rodents, plesiadapids and scandentians. The ICA pattern in leporids is perbullar, but shows structural similarities to stem taxa, whereas the extrabullar ICA course in Ochotona is apparently a highly derived condition. Prolagus shows a mixed character state between leporids and Ochotona in its ICA route. The persistence of the transpromontorial ICA course and similarities in the carotid canal structure among stem taxa and crown leporids support morphological conservatism in Lagomorpha, in contrast to their sister clade Rodentia. This article is part of the theme issue 'The mammalian skull: development, structure and function'.
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Affiliation(s)
- Irina Ruf
- Abteilung Messelforschung und Mammalogie, Senckenberg Forschungsinstitut und Naturmuseum Frankfurt, 60325 Frankfurt am Main, Germany
- Institut für Geowissenschaften, Goethe-Universität Frankfurt am Main, 60438 Frankfurt am Main, Germany
| | - Jin Meng
- Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA
| | - Łucja Fostowicz-Frelik
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637, USA
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, 00-818 Warsaw, Poland
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4
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López‐Torres S, Bhagat R, Bertrand OC, Silcox MT, Fostowicz‐Frelik Ł. Locomotor behavior and hearing sensitivity in an early lagomorph reconstructed from the bony labyrinth. Ecol Evol 2023; 13:e9890. [PMID: 36942029 PMCID: PMC10024310 DOI: 10.1002/ece3.9890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 01/31/2023] [Accepted: 02/24/2023] [Indexed: 03/19/2023] Open
Abstract
The structure of the bony labyrinth is highly informative with respect to locomotor agility (semicircular canals [SCC]) and hearing sensitivity (cochlear and oval windows). Here, we reconstructed the agility and hearing sensitivity of the stem lagomorph Megalagus turgidus from the early Oligocene of the Brule Formation of Nebraska (USA). Megalagus has proportionally smaller SCCs with respect to its body mass compared with most extant leporids but within the modern range of variability, suggesting that it was less agile than most of its modern relatives. A level of agility for Megalagus within the range of modern rabbits is consistent with the evidence from postcranial elements. The hearing sensitivity for Megalagus is in the range of extant lagomorphs for both low- and high-frequency sounds. Our data show that by the early Oligocene stem lagomorphs had already attained fundamentally rabbit-like hearing sensitivity and locomotor behavior, even though Megalagus was not a particularly agile lagomorph. This is likely because Megalagus was more of a woodland dweller than an open-habitat runner. The study of sensory evolution in Lagomorpha is practically unknown, and these results provide first advances in understanding the primitive stages for the order and how the earliest members of this clade perceived their environment.
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Affiliation(s)
- Sergi López‐Torres
- Biological and Chemical Research Centre, Institute of Evolutionary Biology, Faculty of BiologyUniversity of WarsawWarsawPoland
- Division of PaleontologyAmerican Museum of Natural HistoryNew YorkNew YorkUSA
- New York Consortium in Evolutionary PrimatologyNew YorkNew YorkUSA
| | - Raj Bhagat
- Department of AnthropologyUniversity of Toronto ScarboroughTorontoOntarioCanada
| | - Ornella C. Bertrand
- Institut Català de Paleontologia Miquel CrusafontUniversitat Autònoma de Barcelona, Edifici ICTA‐ICPCerdanyola del VallèsSpain
| | - Mary T. Silcox
- Department of AnthropologyUniversity of Toronto ScarboroughTorontoOntarioCanada
| | - Łucja Fostowicz‐Frelik
- Department of Organismal Biology and AnatomyThe University of ChicagoChicagoIllinoisUSA
- Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and PaleoanthropologyChinese Academy of SciencesBeijingChina
- Department of Evolutionary Paleobiology, Institute of PaleobiologyPolish Academy of SciencesWarsawPoland
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Wood-Bailey AP, Cox PG, Sharp AC. The evolution of unique cranial traits in leporid lagomorphs. PeerJ 2022; 10:e14414. [PMID: 36518283 PMCID: PMC9744148 DOI: 10.7717/peerj.14414] [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: 05/16/2022] [Accepted: 10/28/2022] [Indexed: 12/03/2022] Open
Abstract
Background The leporid lagomorphs (rabbits and hares) are adapted to running and leaping (some more than others) and consequently have unique anatomical features that distinguish them from ochotonid lagomorphs (pikas) and from their rodent relatives. Two traits that have received some attention are fenestration of the lateral wall of the maxilla and facial tilting. These features are known to correlate with specialised locomotory form in that the faster running species will generally have fenestration that occupies the dorsal and the anteroventral surface of the maxillary corpus and a more acute facial tilt angle. Another feature is an intracranial joint that circumscribes the back of the skull, thought to facilitate skull mobility. This joint separates the anterior portion of the cranium (including the dentition, rostrum and orbit) from the posterior portion of the cranium (which encompasses the occipital and the auditory complex). Aside from the observation that the intracranial joint is absent in pikas (generalist locomotors) and appears more elaborate in genera with cursorial and saltatorial locomotory habits, the evolutionary history, biomechanical function and comparative anatomy of this feature in leporids lacks a comprehensive evaluation. Methodology The present work analysed the intracranial joint, facial tilting and lateral fenestration of the wall of the maxilla in the context of leporid evolutionary history using a Bayesian inference of phylogeny (18 genera, 23 species) and ancestral state reconstruction. These methods were used to gather information about the likelihood of the presence of these three traits in ancestral groups. Results Our phylogenetic analyses found it likely that the last common ancestor of living leporids had some facial tilting, but that the last common ancestor of all lagomorphs included in the dataset did not. We found that it was likely that the last common ancestor of living leporids had fenestration that occupies the dorsal, but not the anteroventral, surface of the maxillary corpus. We also found it likely that the last common ancestor of living leporids had an intracranial joint, but that the last common ancestor of all living lagomorphs did not. These findings provide a broader context to further studies of evolutionary history and will help inform the formulation and testing of functional hypotheses.
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Affiliation(s)
- Amber P. Wood-Bailey
- Department of Musculoskeletal and Ageing Science, University of Liverpool, Liverpool, Merseyside, United Kingdom
| | - Philip G. Cox
- Department of Archaeology and Hull York Medical School, University of York, York, United Kingdom,Department of Cell and Developmental Biology, University College London, University of London, London, United Kingdom
| | - Alana C. Sharp
- Department of Musculoskeletal and Ageing Science, University of Liverpool, Liverpool, Merseyside, United Kingdom
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Perini FA, Macrini TE, Flynn JJ, Bamba K, Ni X, Croft DA, Wyss AR. Comparative Endocranial Anatomy, Encephalization, and Phylogeny of Notoungulata (Placentalia, Mammalia). J MAMM EVOL 2021. [DOI: 10.1007/s10914-021-09583-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Avilla LS, Mothé D. Out of Africa: A New Afrotheria Lineage Rises From Extinct South American Mammals. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.654302] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The South American native ungulates (SANUs) are usually overlooked in Eutherian phylogenetic studies. In the rare studies where they were included, the diversity of SANUs was underrated, keeping their evolutionary history poorly known. Some authors recognized the SANUs as a monophyletic lineage and formally named it Meridiungulata. Here, we recognized and defined a new supraordinal lineage of Eutheria, the Sudamericungulata, after performing morphological phylogenetic analyses including all lineages of SANUs and Eutheria. The SANUs resulted as non-monophyletic; thus, Meridiungulata is not a natural group; Litopterna and “Didolodontidae” are Panameriungulata and closer to Laurasiatheria than to other “Meridiungulata” (Astrapotheria, Notoungulata, Pyrotheria, and Xenungulata). The other “Meridiungulata” is grouped in the Sudamericungulata, as a new monophyletic lineage of Afrotheria Paenungulata, and shared a common ancestor with Hyracoidea. The divergence between the African and South American lineages is estimated to Early Paleocene, and their interrelationships support the Atlantogea biogeographic model. Shortly afterward, the Sudamericungulata explosively diversified in its four lineages. Confronting the Sudamericungulata evolutionary patterns and the Cenozoic natural events (such as tectonics and climatic and environmental changes, among others) helps to unveil a new chapter in the evolution of Gondwanan Eutheria, as well as the natural history of South America during the Cenozoic.
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8
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Ruf I, Meng J, Fostowicz-Frelik Ł. Anatomy of the Nasal and Auditory Regions of the Fossil Lagomorph Palaeolagus haydeni: Systematic and Evolutionary Implications. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.636110] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Palaeolagus, a late Eocene to early Miocene North American lagomorph genus, represented by numerous and well-preserved specimens, has been long considered a basal leporid, although it is currently understood as a stem lagomorph. Based on micro-computed tomography (μCT) data and 3D reconstructions, here we present the first description of intracranial structures of the nasal and auditory regions of a complete skull of Palaeolagus haydeni from the early Oligocene of Nebraska. Although Palaeolagus haydeni shows a puzzling mixture of extant leporid and ochotonid characters, it helps to polarize and re-evaluate already known lagomorph intracranial characters based on outgroup comparison with Rodentia and Scandentia. Common derived features of Palaeolagus haydeni and extant Lagomorpha are the dendritic maxilloturbinal and the excavated nasoturbinal that contacts the lamina semicircularis. Generally, Palaeolagus haydeni and Leporidae have several characters in common, some of which are certainly plesiomorphic (e.g., thin wall of bulla tympani and flat conic cochlea). Palaeolagus haydeni resembles Leporidae in having an interturbinal between the two frontoturbinals, and three ethmoturbinals plus one interturbinal between ethmoturbinal I and II. Now, this should also be regarded as a plesiomorphic grundplan pattern for Leporidae whereas ochotonids are derived from the lagomorph grundplan as concerns the number of frontoturbinals. Concerning the middle ear, Palaeolagus haydeni significantly contributes to the polarization of the anterior anchoring of the malleus in extant lagomorphs. Palaeolagus haydeni resembles the pattern observed in early ontogenetic stages of Ochotonidae, i.e., the attachment of the malleus to the ectotympanic via a short processus anterior. The patterns in adult ochotonids and leporids now can be regarded as two different and apomorphic character states. Autapomorphic characters of Palaeolagus haydeni are the reduced frontoturbinal 2 and the additional anterolaterally oriented process of the lamina semicircularis. Interestingly, among the investigated intracranial structures the loss of the secondary crus commune is the only apomorphic grundplan character of crown Lagomorpha.
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Bertrand OC, Püschel HP, Schwab JA, Silcox MT, Brusatte SL. The impact of locomotion on the brain evolution of squirrels and close relatives. Commun Biol 2021; 4:460. [PMID: 33846528 PMCID: PMC8042109 DOI: 10.1038/s42003-021-01887-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 02/22/2021] [Indexed: 02/01/2023] Open
Abstract
How do brain size and proportions relate to ecology and evolutionary history? Here, we use virtual endocasts from 38 extinct and extant rodent species spanning 50+ million years of evolution to assess the impact of locomotion, body mass, and phylogeny on the size of the brain, olfactory bulbs, petrosal lobules, and neocortex. We find that body mass and phylogeny are highly correlated with relative brain and brain component size, and that locomotion strongly influences brain, petrosal lobule, and neocortical sizes. Notably, species living in trees have greater relative overall brain, petrosal lobule, and neocortical sizes compared to other locomotor categories, especially fossorial taxa. Across millions of years of Eocene-Recent environmental change, arboreality played a major role in the early evolution of squirrels and closely related aplodontiids, promoting the expansion of the neocortex and petrosal lobules. Fossoriality in aplodontiids had an opposing effect by reducing the need for large brains.
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Affiliation(s)
- Ornella C Bertrand
- School of GeoSciences, University of Edinburgh, Grant Institute, Edinburgh, Scotland, UK.
| | - Hans P Püschel
- School of GeoSciences, University of Edinburgh, Grant Institute, Edinburgh, Scotland, UK
| | - Julia A Schwab
- School of GeoSciences, University of Edinburgh, Grant Institute, Edinburgh, Scotland, UK
| | - Mary T Silcox
- Department of Anthropology, University of Toronto Scarborough, Toronto, ON, Canada
| | - Stephen L Brusatte
- School of GeoSciences, University of Edinburgh, Grant Institute, Edinburgh, Scotland, UK
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Wolniewicz AS, Fostowicz-Frelik Ł. CT-Informed Skull Osteology of Palaeolagus haydeni (Mammalia: Lagomorpha) and Its Bearing on the Reconstruction of the Early Lagomorph Body Plan. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.634757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Lagomorpha is a clade of herbivorous mammals nested within Euarchontoglires, one of the major placental groups represented today. It comprises two extant families with markedly different body plans: the long-eared and long-limbed Leporidae (hares and rabbits) and the short-eared and short-limbed Ochotonidae (pikas). These two lagomorph lineages diverged probably during the latest Eocene/early Oligocene, but it is unclear whether the last common ancestor of crown lagomorphs was more leporid- or more ochotonid-like in morphology. Palaeolagus, an early lagomorph dominant in western North America from the late Eocene to Oligocene is of particular importance for addressing this controversy. Here, we present new and comprehensive data on the cranial anatomy of Palaeolagus haydeni, the type species for the genus, based on micro-computed tomography (μCT). Our μCT data allow us to confirm, revise and score for the very first time the states of several leporid-like and ochotonid-like characters in the skull of Palaeolagus. This mixed cranial architecture differentiates Palaeolagus from the crown groups of Lagomorpha and supports its phylogenetic status as a stem taxon.
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11
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Bhagat R, Bertrand OC, Silcox MT. Evolution of arboreality and fossoriality in squirrels and aplodontid rodents: Insights from the semicircular canals of fossil rodents. J Anat 2021; 238:96-112. [PMID: 32812227 PMCID: PMC7754939 DOI: 10.1111/joa.13296] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/17/2020] [Accepted: 07/23/2020] [Indexed: 01/03/2023] Open
Abstract
Reconstructing locomotor behaviour for fossil animals is typically done with postcranial elements. However, for species only known from cranial material, locomotor behaviour is difficult to reconstruct. The semicircular canals (SCCs) in the inner ear provide insight into an animal's locomotor agility. A relationship exists between the size of the SCCs relative to body mass and the jerkiness of an animal's locomotion. Additionally, studies have also demonstrated a relationship between SCC orthogonality and angular head velocity. Here, we employ two metrics for reconstructing locomotor agility, radius of curvature dimensions and SCC orthogonality, in a sample of twelve fossil rodents from the families Ischyromyidae, Sciuridae and Aplodontidae. The method utilizing radius of curvature dimensions provided a reconstruction of fossil rodent locomotor behaviour that is more consistent with previous studies assessing fossil rodent locomotor behaviour compared to the method based on SCC orthogonality. Previous work on ischyromyids suggests that this group displayed a variety of locomotor modes. Members of Paramyinae and Ischyromyinae have relatively smaller SCCs and are reconstructed to be relatively slower compared to members of Reithroparamyinae. Early members of the Sciuroidea clade including the sciurid Cedromus wilsoni and the aplodontid Prosciurus relictus are reconstructed to be more agile than ischyromyids, in the range of extant arboreal squirrels. This reconstruction supports previous inferences that arboreality was likely an ancestral trait for this group. Derived members of Sciuridae and Aplodontidae vary in agility scores. The fossil squirrel Protosciurus cf. rachelae is inferred from postcranial material as arboreal, which is in agreement with its high agility, in the range of extant arboreal squirrels. In contrast, the fossil aplodontid Mesogaulus paniensis has a relatively low agility score, similar to the fossorial Aplodontia rufa, the only living aplodontid rodent. This result is in agreement with its postcranial reconstruction as fossorial and with previous indications that early aplodontids were more arboreal than their burrowing descendants.
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Affiliation(s)
- Raj Bhagat
- Department of AnthropologyUniversity of Toronto ScarboroughTorontoONCanada
| | | | - Mary T. Silcox
- Department of AnthropologyUniversity of Toronto ScarboroughTorontoONCanada
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12
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López-Torres S, Bertrand OC, Lang MM, Silcox MT, Fostowicz-Frelik Ł. Cranial endocast of the stem lagomorph Megalagus and brain structure of basal Euarchontoglires. Proc Biol Sci 2020; 287:20200665. [PMID: 32576117 PMCID: PMC7329053 DOI: 10.1098/rspb.2020.0665] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Early lagomorphs are central to our understanding of how the brain evolved in Glires (rodents, lagomorphs and their kin) from basal members of Euarchontoglires (Glires + Euarchonta, the latter grouping primates, treeshrews, and colugos). Here, we report the first virtual endocast of the fossil lagomorph Megalagus turgidus, from the Orella Member of the Brule Formation, early Oligocene, Nebraska, USA. The specimen represents one of the oldest nearly complete lagomorph skulls known. Primitive aspects of the endocranial morphology in Megalagus include large olfactory bulbs, exposure of the midbrain, a small neocortex and a relatively low encephalization quotient. Overall, this suggests a brain morphology closer to that of other basal members of Euarchontoglires (e.g. plesiadapiforms and ischyromyid rodents) than to that of living lagomorphs. However, the well-developed petrosal lobules in Megalagus, comparable to the condition in modern lagomorphs, suggest early specialization in that order for the stabilization of eye movements necessary for accurate visual tracking. Our study sheds new light on the reconstructed morphology of the ancestral brain in Euarchontoglires and fills a critical gap in the understanding of palaeoneuroanatomy of this major group of placental mammals.
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Affiliation(s)
- Sergi López-Torres
- Division of Paleontology, American Museum of Natural History, New York, NY, USA.,Richard Gilder Graduate School, American Museum of Natural History, New York, NY, USA.,New York Consortium in Evolutionary Primatology, New York, NY, USA.,Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland
| | - Ornella C Bertrand
- School of Geosciences, Grant Institute, University of Edinburgh, Edinburgh EH9 3FE, UK
| | - Madlen M Lang
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Mary T Silcox
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Łucja Fostowicz-Frelik
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, Poland.,Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, People's Republic of China.,CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, People's Republic of China
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13
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Springer MS, Foley NM, Brady PL, Gatesy J, Murphy WJ. Evolutionary Models for the Diversification of Placental Mammals Across the KPg Boundary. Front Genet 2019; 10:1241. [PMID: 31850081 PMCID: PMC6896846 DOI: 10.3389/fgene.2019.01241] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 11/08/2019] [Indexed: 01/29/2023] Open
Abstract
Deciphering the timing of the placental mammal radiation is a longstanding problem in evolutionary biology, but consensus on the tempo and mode of placental diversification remains elusive. Nevertheless, an accurate timetree is essential for understanding the role of important events in Earth history (e.g., Cretaceous Terrestrial Revolution, KPg mass extinction) in promoting the taxonomic and ecomorphological diversification of Placentalia. Archibald and Deutschman described three competing models for the diversification of placental mammals, which are the Explosive, Long Fuse, and Short Fuse Models. More recently, the Soft Explosive Model and Trans-KPg Model have emerged as additional hypotheses for the placental radiation. Here, we review molecular and paleontological evidence for each of these five models including the identification of general problems that can negatively impact divergence time estimates. The Long Fuse Model has received more support from relaxed clock studies than any of the other models, but this model is not supported by morphological cladistic studies that position Cretaceous eutherians outside of crown Placentalia. At the same time, morphological cladistics has a poor track record of reconstructing higher-level relationships among the orders of placental mammals including the results of new pseudoextinction analyses that we performed on the largest available morphological data set for mammals (4,541 characters). We also examine the strengths and weaknesses of different timetree methods (node dating, tip dating, and fossilized birth-death dating) that may now be applied to estimate the timing of the placental radiation. While new methods such as tip dating are promising, they also have problems that must be addressed if these methods are to effectively discriminate among competing hypotheses for placental diversification. Finally, we discuss the complexities of timetree estimation when the signal of speciation times is impacted by incomplete lineage sorting (ILS) and hybridization. Not accounting for ILS results in dates that are older than speciation events. Hybridization, in turn, can result in dates than are younger or older than speciation dates. Disregarding this potential variation in "gene" history across the genome can distort phylogenetic branch lengths and divergence estimates when multiple unlinked genomic loci are combined together in a timetree analysis.
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Affiliation(s)
- Mark S. Springer
- Department of Evolution, Ecology, and Evolutionary Biology, University of California, Riverside, Riverside, CA, United States
| | - Nicole M. Foley
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, United States
| | - Peggy L. Brady
- Department of Evolution, Ecology, and Evolutionary Biology, University of California, Riverside, Riverside, CA, United States
| | - John Gatesy
- Division of Vertebrate Zoology, American Museum of Natural History, New York, NY, United States
| | - William J. Murphy
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, United States
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Asher RJ, Smith MR, Rankin A, Emry RJ. Congruence, fossils and the evolutionary tree of rodents and lagomorphs. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190387. [PMID: 31417738 PMCID: PMC6689570 DOI: 10.1098/rsos.190387] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/19/2019] [Indexed: 05/10/2023]
Abstract
Given an evolutionary process, we expect distinct categories of heritable data, sampled in ever larger amounts, to converge on a single tree of historical relationships. We tested this assertion by undertaking phylogenetic analyses of a new morphology-DNA dataset for mammals, focusing on Glires and including the oldest known skeletons of geomyoid and Ischyromys rodents. Our results support geomyoids in the mouse-related clade (Myomorpha) and a ricochetal locomotor pattern for the common ancestor of geomyoid rodents. They also support Ischyromys in the squirrel-related clade (Sciuromorpha) and the evolution of sciurids and Aplodontia from extinct, 'protrogomorph'-grade rodents. Moreover, ever larger samples of characters from our dataset increased congruence with an independent, well-corroborated tree. Addition of morphology from fossils increased congruence to a greater extent than addition of morphology from extant taxa, consistent with fossils' temporal proximity to the common ancestors of living species, reflecting the historical, phylogenetic signal present in our data, particularly in morphological characters from fossils. Our results support the widely held but poorly tested intuition that fossils resemble the common ancestors shared by living species, and that fossilizable hard tissues (i.e. bones and teeth) help to reconstruct the evolutionary tree of life.
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Affiliation(s)
- Robert J. Asher
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Martin R. Smith
- Department of Earth Sciences, University of Durham, Durham, UK
| | - Aime Rankin
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Robert J. Emry
- Department of Paleobiology, Smithsonian Institution, Washington, DC, USA
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15
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Caccavo A, Weksler M. Mesial hyperdontia in Sigmodontinae (Rodentia: Cricetidae), with comments on the evolution of the anteroconid in Myomorpha. MAMMALIA 2019. [DOI: 10.1515/mammalia-2018-0162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Supernumerary teeth are common dental anomalies reported in rodents, mainly occurring distally to molars. We report the first case of mesial hyperdontia in wild-caught sigmodontine: a simplified tooth anterior to the right first lower molar in Neacomys amoenus. It affected the first molar morphology, which exhibits an underdeveloped mesial region with a reduced anterior conulid, a similar pattern observed in early known myomorph fossils, including lineages that still possess the last premolar. However, only lineages without premolar display an elongated first lower molar with a large anteroconid, as observed in extant Myomorpha. During the odontogenesis in myomorphs, the posteriormost vestigial diastemal tooth bud, located at the same locus of the last lower premolar, has its development arrested and merges with the cap of the first molar. This process might have contributed to the development of an increased anteroconid in this lineage. The abnormal Neacomys’ atavistic phenotype corroborates the hypothesis that the absorption of the primordium of the last lower premolar had played an important role in the development of first molar’s mesial region. Additionally, it also might have promoted the evolutionary transition from a reduced conulid into an enlarged anteroconid, as deduced from the fossil record and developmental evidence
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Affiliation(s)
- Aldo Caccavo
- Universidade Federal do Rio de Janeiro, Museu Nacional , Programa de Pós-Graduação em Zoologia , Rio de Janeiro, RJ 20940-040 , Brazil
- Universidade Federal do Rio de Janeiro, Museu Nacional , Departamento de Vertebrados, Setor de Mastozoologia , Rio de Janeiro, RJ 20940-040 , Brazil
| | - Marcelo Weksler
- Universidade Federal do Rio de Janeiro, Museu Nacional , Departamento de Vertebrados, Setor de Mastozoologia , Rio de Janeiro, RJ 20940-040 , Brazil
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Muchlinski MN, Wible JR, Corfe I, Sullivan M, Grant RA. Good Vibrations: The Evolution of Whisking in Small Mammals. Anat Rec (Hoboken) 2018; 303:89-99. [PMID: 30332721 DOI: 10.1002/ar.23989] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 01/14/2018] [Indexed: 01/11/2023]
Abstract
While most mammals have whiskers, some tactile specialists-mainly small, nocturnal, and arboreal species-can actively move their whiskers in a symmetrical, cyclic movement called whisking. Whisking enables mammals to rapidly, tactually scan their environment to efficiently guide locomotion and foraging in complex habitats. The muscle architecture that enables whisking is preserved from marsupials to primates, prompting researchers to suggest that a common ancestor might have had moveable whiskers. Studying the evolution of whisker touch sensing is difficult, and we suggest that measuring an aspect of skull morphology that correlates with whisking would enable comparisons between extinct and extant mammals. We find that whisking mammals have larger infraorbital foramen (IOF) areas, which indicates larger infraorbital nerves and an increase in sensory acuity. While this relationship is quite variable and IOF area cannot be used to solely predict the presence of whisking, whisking mammals all have large IOF areas. Generally, this pattern holds true regardless of an animal's substrate preferences or activity patterns. Data from fossil mammals and ancestral character state reconstruction and tracing techniques for extant mammals suggest that whisking is not the ancestral state for therian mammals. Instead, whisking appears to have evolved independently as many as seven times across the clades Marsupialia, Afrosoricida, Eulipotyphla, and Rodentia, with Xenarthra the only placental superordinal clade lacking whisking species. However, the term whisking only captures symmetrical and rhythmic movements of the whiskers, rather than all possible whisker movements, and early mammals may still have had moveable whiskers. Anat Rec, 2018. © 2018 American Association for Anatomy.
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Affiliation(s)
- Magdalena N Muchlinski
- Center for Anatomical Sciences, University of North Texas Health Science Center, Fort Worth, Texas
| | - John R Wible
- Section of Mammals, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania
| | - Ian Corfe
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Matthew Sullivan
- Division of Biology and Conservation Ecology, Manchester Metropolitan University, Manchester, UK
| | - Robyn A Grant
- Division of Biology and Conservation Ecology, Manchester Metropolitan University, Manchester, UK
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Fostowicz-Frelik Ł, Li Q, Ni X. Oldest ctenodactyloid tarsals from the Eocene of China and evolution of locomotor adaptations in early rodents. BMC Evol Biol 2018; 18:150. [PMID: 30286712 PMCID: PMC6172738 DOI: 10.1186/s12862-018-1259-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 09/10/2018] [Indexed: 11/15/2022] Open
Abstract
Background Tamquammys has been considered one of the basal ctenodactyloid rodents, which has been documented in the earliest to middle Eocene (~ 56.0–48.5 Ma) in China. It was the most abundant and widespread rodent genus in the Erlian Basin (Nei Mongol, China) and dominated Arshantan small-mammal faunas of that region. Here for the first time we describe the morphology of the astragalocalcaneal complex in Tamquammys robustus (larger) and T. wilsoni, and interpret it against the background of locomotor adaptations of basal Euarchontoglires (rodents, lagomorphs, tree shrews, and primates). Results The comparative morphology of the tarsal elements in Tamquammys robustus and T. wilsoni shows overall slenderness of the bones and their similarity to the tarsal elements of Rattus, a generalist species, and those of small rock squirrels (e.g. Sciurotamias). The two species differ slightly in their cursorial ability; smaller T. wilsoni shows some adaptations to climbing. The results of principal component analysis of the calcaneus and astragalus support this observation and place T. robustus in-between Rattus and ground/rock squirrel morphospace, and T. wilsoni closer to euarchontans, Tupaia and Purgatorius. Conclusions The morphology of the tarsal elements in Tamquammys indicates a generalist rodent morphotype with no particular adaptations to arboreality. We suggest that Tamquammys as a basal ctenodactyloid is closer to the ancestral astragalocalcaneal morphology of rodents than that of more derived North American paramyines of similar age. Overall similarity in Tamquammys tarsal elements structure to Purgatorius, a basal primate, may point to the antiquity of the tarsal structure in Tamquammys and a generally unspecialized foot structure in early Euarchontoglires. Electronic supplementary material The online version of this article (10.1186/s12862-018-1259-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Łucja Fostowicz-Frelik
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 100044, Beijing, People's Republic of China. .,Institute of Paleobiology, Polish Academy of Sciences, 00-818, Warszawa, PL, Poland.
| | - Qian Li
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 100044, Beijing, People's Republic of China
| | - Xijun Ni
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 100044, Beijing, People's Republic of China
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18
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López-Torres S, Fostowicz-Frelik Ł. A new Eocene anagalid (Mammalia: Euarchontoglires) from Mongolia and its implications for the group's phylogeny and dispersal. Sci Rep 2018; 8:13955. [PMID: 30224674 PMCID: PMC6141491 DOI: 10.1038/s41598-018-32086-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 08/30/2018] [Indexed: 11/28/2022] Open
Abstract
Anagalidae are extinct primitive Euarchontoglires from Asia, regarded as relatively closely related to basal Glires. So far, the group has been reported only from China and stratigraphically spans from the early Paleocene to the latest Eocene/earliest Oligocene. Anagalids are characterized by a relatively full dental formula featuring slightly enlarged semi-procumbent incisors, prominent canines, and tall cheek teeth with usually heavily worn crowns, indicative of an abrasive diet. Here we report a new genus and species from the late Eocene Ergilin Dzo Formation in southern Mongolia. The first non-Chinese anagalid is also the northernmost record of the family. Zofiagale ergilinensis gen. and sp.nov. is remarkable for its relatively small size (comparable only to the Paleocene genera Huaiyangale and Stenanagale), lack of P1, and molariform teeth showing almost no wear, suggesting a different diet than most Anagalidae. Furthermore, its molars display a strong buccal cingulum, a character in anagalids shared only with Wanogale. Our phylogenetic analysis of representatives of all anagalid genera based on 82 dental characters places Anagale and Anaptogale as the most basal lineages and clusters Zofiagale gen. nov. together with Qipania and Hsiuannania. These results suggest three independent northward dispersal events within the family in the late Eocene.
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Affiliation(s)
- Sergi López-Torres
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, PL-00-818, Poland
| | - Łucja Fostowicz-Frelik
- Department of Evolutionary Paleobiology, Institute of Paleobiology, Polish Academy of Sciences, Warsaw, PL-00-818, Poland.
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, People's Republic of China.
- Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Beijing, 100044, People's Republic of China.
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19
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New Virtual Endocasts of Eocene Ischyromyidae and Their Relevance in Evaluating Neurological Changes Occurring Through Time in Rodentia. J MAMM EVOL 2018. [DOI: 10.1007/s10914-017-9425-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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20
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Fujita K, Nishimoto S, Fujiwara T, Sotsuka Y, Tonooka M, Kawai K, Kakibuchi M. A new rabbit model of impaired wound healing in an X-ray-irradiated field. PLoS One 2017; 12:e0184534. [PMID: 28886194 PMCID: PMC5590982 DOI: 10.1371/journal.pone.0184534] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/25/2017] [Indexed: 11/18/2022] Open
Abstract
Radiation is an important therapy for cancer with many benefits; however, its side effects, such as impaired wound healing, are a major problem. While many attempts have been made to overcome this particular disadvantage, there are few effective treatments for impaired wound healing in an X-ray-irradiated field. One reason for this deficiency is the lack of experimental models, especially animal models. We have previously reported a mouse model of impaired wound healing in which the irradiation area was restricted to the hindlimbs. In this mouse model, due to the size of the animal, a diameter of five millimeters was considered the largest wound size suitable for the model. In addition, the transplanted cells had to be harvested from other inbred animals. To investigate larger wounds and the impact of autologous specimen delivery, a rabbit model was developed. Rabbits were kept in a special apparatus to shield the body and hindlimbs while the irradiation field was exposed to radiation. Six weeks after irradiation, a 2 x 2 cm, full-thickness skin defect was made inside the irradiation field. Then, the wound area was observed over time. The wound area after irradiation was larger than that without irradiation at all time points. Both angiogenesis and collagen formation were reduced. For further study, as an example of using this model, the effect of autologous platelet-rich plasma (PRP) was observed. Autologous PRP from peripheral blood (pb-PRP) and bone marrow aspirate (bm-PRP) was processed and injected into the wounds in the irradiated field. Two weeks later, the wounds treated with bm-PRP were significantly smaller than those treated with phosphate buffer vehicle controls. In contrast, the wounds treated with pb-PRP were not significantly different from the controls. This rabbit model is useful for investigating the mechanism of impaired wound healing in an X-ray-irradiated field.
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Affiliation(s)
- Kazutoshi Fujita
- Department of Plastic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Soh Nishimoto
- Department of Plastic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
- * E-mail:
| | - Toshihiro Fujiwara
- Department of Plastic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Yohei Sotsuka
- Department of Plastic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Maki Tonooka
- Department of Plastic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Kenichiro Kawai
- Department of Plastic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Masao Kakibuchi
- Department of Plastic Surgery, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
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21
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A comparative analysis of infraorbital foramen size in Paleogene euarchontans. J Hum Evol 2017; 105:57-68. [DOI: 10.1016/j.jhevol.2017.01.017] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 01/19/2017] [Accepted: 01/26/2017] [Indexed: 11/21/2022]
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22
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Halliday TJD, Upchurch P, Goswami A. Resolving the relationships of Paleocene placental mammals. Biol Rev Camb Philos Soc 2017; 92:521-550. [PMID: 28075073 PMCID: PMC6849585 DOI: 10.1111/brv.12242] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 10/28/2015] [Accepted: 11/04/2015] [Indexed: 01/25/2023]
Abstract
The 'Age of Mammals' began in the Paleocene epoch, the 10 million year interval immediately following the Cretaceous-Palaeogene mass extinction. The apparently rapid shift in mammalian ecomorphs from small, largely insectivorous forms to many small-to-large-bodied, diverse taxa has driven a hypothesis that the end-Cretaceous heralded an adaptive radiation in placental mammal evolution. However, the affinities of most Paleocene mammals have remained unresolved, despite significant advances in understanding the relationships of the extant orders, hindering efforts to reconstruct robustly the origin and early evolution of placental mammals. Here we present the largest cladistic analysis of Paleocene placentals to date, from a data matrix including 177 taxa (130 of which are Palaeogene) and 680 morphological characters. We improve the resolution of the relationships of several enigmatic Paleocene clades, including families of 'condylarths'. Protungulatum is resolved as a stem eutherian, meaning that no crown-placental mammal unambiguously pre-dates the Cretaceous-Palaeogene boundary. Our results support an Atlantogenata-Boreoeutheria split at the root of crown Placentalia, the presence of phenacodontids as closest relatives of Perissodactyla, the validity of Euungulata, and the placement of Arctocyonidae close to Carnivora. Periptychidae and Pantodonta are resolved as sister taxa, Leptictida and Cimolestidae are found to be stem eutherians, and Hyopsodontidae is highly polyphyletic. The inclusion of Paleocene taxa in a placental phylogeny alters interpretations of relationships and key events in mammalian evolutionary history. Paleocene mammals are an essential source of data for understanding fully the biotic dynamics associated with the end-Cretaceous mass extinction. The relationships presented here mark a critical first step towards accurate reconstruction of this important interval in the evolution of the modern fauna.
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Affiliation(s)
- Thomas J. D. Halliday
- Department of Earth SciencesUniversity College LondonGower StreetLondonWC1E 6BTU.K.
- Department of Genetics, Evolution and EnvironmentUniversity College LondonGower StreetLondonWC1E 6BTU.K.
| | - Paul Upchurch
- Department of Earth SciencesUniversity College LondonGower StreetLondonWC1E 6BTU.K.
| | - Anjali Goswami
- Department of Earth SciencesUniversity College LondonGower StreetLondonWC1E 6BTU.K.
- Department of Genetics, Evolution and EnvironmentUniversity College LondonGower StreetLondonWC1E 6BTU.K.
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Functional Anatomy of the Forelimb of Plesiotypotherium achirense (Mammalia, Notoungulata, Mesotheriidae) and Evolutionary Insights at the Family Level. J MAMM EVOL 2017. [DOI: 10.1007/s10914-016-9372-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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24
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Boyer DM, Kirk EC, Silcox MT, Gunnell GF, Gilbert CC, Yapuncich GS, Allen KL, Welch E, Bloch JI, Gonzales LA, Kay RF, Seiffert ER. Internal carotid arterial canal size and scaling in Euarchonta: Re-assessing implications for arterial patency and phylogenetic relationships in early fossil primates. J Hum Evol 2016; 97:123-44. [DOI: 10.1016/j.jhevol.2016.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 06/03/2016] [Accepted: 06/04/2016] [Indexed: 01/31/2023]
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25
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Bloch JI, Chester SG, Silcox MT. Cranial anatomy of Paleogene Micromomyidae and implications for early primate evolution. J Hum Evol 2016; 96:58-81. [DOI: 10.1016/j.jhevol.2016.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 04/04/2016] [Accepted: 04/06/2016] [Indexed: 11/29/2022]
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26
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Brocklehurst RJ, Crumpton N, Button E, Asher RJ. Jaw anatomy of Potamogale velox (Tenrecidae, Afrotheria) with a focus on cranial arteries and the coronoid canal in mammals. PeerJ 2016; 4:e1906. [PMID: 27114870 PMCID: PMC4841219 DOI: 10.7717/peerj.1906] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/16/2016] [Indexed: 11/20/2022] Open
Abstract
Afrotheria is a strongly supported clade within placental mammals, but morphological synapomorphies for the entire group have only recently come to light. Soft tissue characters represent an underutilized source of data for phylogenetic analysis, but nonetheless provide features shared by some or all members of Afrotheria. Here, we investigate the developmental anatomy of Potamogale velox (Tenrecidae) with histological and computerized tomographic data at different ontogenetic ages, combined with osteological data from other mammals, to investigate patterns of cranial arterial supply and the distribution of the coronoid canal. Potamogale is atypical among placental mammals in exhibiting a small superior stapedial artery, a primary supply of the posterior auricular by the posterior stapedial artery, and the development of vascular plexuses (possibly with relevance for heat exchange) in the posterior and dorsal regions of its neck. In addition, the posterior aspect of Meckel's cartilage increases its medial deflection in larger embryonic specimens as the mandibular condyle extends mediolaterally during embryogenesis. We also map the distribution of the coronoid canal across mammals, and discuss potential confusion of this feature with alveoli of the posterior teeth. The widespread distribution of the coronoid canal among living and fossil proboscideans, sirenians, and hyracoids supports previous interpretations that a patent coronoid canal is a synapomorphy of paenungulates, but not afrotherians as a whole.
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Affiliation(s)
- Robert J Brocklehurst
- Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom; Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - Nick Crumpton
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom; Research Department of Cell & Developmental Biology, University College London, United Kingdom
| | - Evie Button
- Department of Zoology, University of Cambridge , Cambridge , United Kingdom
| | - Robert J Asher
- Department of Zoology, University of Cambridge , Cambridge , United Kingdom
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27
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Bertrand OC, Amador-Mughal F, Silcox MT. Virtual endocasts of Eocene Paramys (Paramyinae): oldest endocranial record for Rodentia and early brain evolution in Euarchontoglires. Proc Biol Sci 2016; 283:20152316. [PMID: 26817776 PMCID: PMC4795019 DOI: 10.1098/rspb.2015.2316] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/07/2016] [Indexed: 11/12/2022] Open
Abstract
Understanding the pattern of brain evolution in early rodents is central to reconstructing the ancestral condition for Glires, and for other members of Euarchontoglires including Primates. We describe the oldest virtual endocasts known for fossil rodents, which pertain to Paramys copei (Early Eocene) and Paramys delicatus (Middle Eocene). Both specimens of Paramys have larger olfactory bulbs and smaller paraflocculi relative to total endocranial volume than later occurring rodents, which may be primitive traits for Rodentia. The encephalization quotients (EQs) of Pa. copei and Pa. delicatus are higher than that of later occurring (Oligocene) Ischyromys typus, which contradicts the hypothesis that EQ increases through time in all mammalian orders. However, both species of Paramys have a lower relative neocortical surface area than later rodents, suggesting neocorticalization occurred through time in this Order, although to a lesser degree than in Primates. Paramys has a higher EQ but a lower neocortical ratio than any stem primate. This result contrasts with the idea that primates were always exceptional in their degree of overall encephalization and shows that relative brain size and neocortical surface area do not necessarily covary through time. As such, these data contradict assumptions made about the pattern of brain evolution in Euarchontoglires.
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Affiliation(s)
- Ornella C Bertrand
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada M1C 1A4
| | - Farrah Amador-Mughal
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada M1C 1A4
| | - Mary T Silcox
- Department of Anthropology, University of Toronto Scarborough, Toronto, Ontario, Canada M1C 1A4
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28
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Ramdarshan A, Orliac MJ. Endocranial morphology ofMicrochoerus erinaceus(Euprimates, Tarsiiformes) and early evolution of the Euprimates brain. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2015; 159:5-16. [DOI: 10.1002/ajpa.22868] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 08/31/2015] [Accepted: 09/02/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Anusha Ramdarshan
- Paleontology division, Institut des Sciences de l'Evolution, UMR 5554 CNRS, IRD, EPHE; Université De Montpellier; 34095 Montpellier Cedex 5 France
| | - Maeva J. Orliac
- Paleontology division, Institut des Sciences de l'Evolution, UMR 5554 CNRS, IRD, EPHE; Université De Montpellier; 34095 Montpellier Cedex 5 France
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A large mimotonid from the middle Eocene of China sheds light on the evolution of lagomorphs and their kin. Sci Rep 2015; 5:9394. [PMID: 25818513 PMCID: PMC4377629 DOI: 10.1038/srep09394] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 02/27/2015] [Indexed: 11/12/2022] Open
Abstract
Mimotonids share their closest affinity with lagomorphs and were a rare and endemic faunal element of Paleogene mammal assemblages of central Asia. Here we describe a new species, Mimolagusaurorae from the Middle Eocene of Nei Mongol (China). This species belongs to one of the most enigmatic genera of fossil Glires, previously known only from the type and only specimen from the early Oligocene of Gansu (China). Our finding extends the earliest occurrence of the genus by at least 10 million years in the Paleogene of Asia, which closes the gap between Mimolagus and other mimotonids that are known thus far from middle Eocene or older deposits. The new species is one of the largest known pre-Oligocene Glires. As regards duplicidentates, Mimolagus is comparable with the largest Neogene continental leporids, namely hares of the genus Lepus. Our results suggest that ecomorphology of this species was convergent on that of small perissodactyls that dominated faunas of the Mongolian Plateau in the Eocene, and probably a result of competitive pressure from other Glires, including a co-occurring mimotonid, Gomphos.
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Li Q, Meng J. New Ctenodactyloid Rodents from the Erlian Basin, Nei Mongol, China, and the Phylogenetic Relationships of Eocene Asian Ctenodactyloids. AMERICAN MUSEUM NOVITATES 2015. [DOI: 10.1206/3828.1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Billet G, de Muizon C, Schellhorn R, Ruf I, Ladevèze S, Bergqvist L. Petrosal and inner ear anatomy and allometry amongst specimens referred to Litopterna (Placentalia). Zool J Linn Soc 2015. [DOI: 10.1111/zoj.12219] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Guillaume Billet
- Steinmann-Institut für Geologie; Mineralogie und Paläontologie; Rheinische Friedrich-Wilhelms-Universität Bonn; Nussallee 8 53115 Bonn Germany
- CR2P - UMR 7207 CNRS; MNHN; Univ Paris 06 - Muséum national d'Histoire naturelle; 8 rue Buffon CP 38 75005 Paris France
| | - Christian de Muizon
- CR2P - UMR 7207 CNRS; MNHN; Univ Paris 06 - Muséum national d'Histoire naturelle; 8 rue Buffon CP 38 75005 Paris France
| | - Rico Schellhorn
- Steinmann-Institut für Geologie; Mineralogie und Paläontologie; Rheinische Friedrich-Wilhelms-Universität Bonn; Nussallee 8 53115 Bonn Germany
| | - Irina Ruf
- Steinmann-Institut für Geologie; Mineralogie und Paläontologie; Rheinische Friedrich-Wilhelms-Universität Bonn; Nussallee 8 53115 Bonn Germany
- Senckenberg Forschungsinstitut und Naturmuseum Frankfurt; Abteilung Paläoanthropologie und Messelforschung; Senckenberganlage 25 60325 Frankfurt am Main Germany
| | - Sandrine Ladevèze
- CR2P - UMR 7207 CNRS; MNHN; Univ Paris 06 - Muséum national d'Histoire naturelle; 8 rue Buffon CP 38 75005 Paris France
| | - Lilian Bergqvist
- Avenida Athos da Silveira Ramos; 274, bloco G; Centro de Ciências Matemáticas e da Natureza; Universidade Federal do Rio de Janeiro; Rio de Janeiro 21941-916 Brasil
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Averianov AO, Lopatin AV. High-level systematics of placental mammals: Current status of the problem. BIOL BULL+ 2014. [DOI: 10.1134/s1062359014090039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Gatesy J, Springer MS. Phylogenetic analysis at deep timescales: Unreliable gene trees, bypassed hidden support, and the coalescence/concatalescence conundrum. Mol Phylogenet Evol 2014; 80:231-66. [DOI: 10.1016/j.ympev.2014.08.013] [Citation(s) in RCA: 239] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Revised: 07/26/2014] [Accepted: 08/10/2014] [Indexed: 11/16/2022]
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CUENCA-BESCÓS G, LÓPEZ-GARCÍA JM, GALINDO-PELLICENA MA, GARCÍA-PEREA R, GISBERT J, ROFES J, VENTURA J. Pleistocene history of Iberomys
, an endangered endemic rodent from southwestern Europe. Integr Zool 2014; 9:481-97. [DOI: 10.1111/1749-4877.12053] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Gloria CUENCA-BESCÓS
- Research Group Aragosaurus-IUCA, Paleontology, Earth Sciences Department; University of Zaragoza; Zaragoza Spain
| | - Juan Manuel LÓPEZ-GARCÍA
- Research Group of Paleobiology and Prehistory, Human Studies Department; University of Ferrara; Ferrara Italy
| | | | - Rosa GARCÍA-PEREA
- GALEMIA; Conservation and Study of Forgotten Vertebrates; Madrid Spain
| | - Julio GISBERT
- GALEMIA; Conservation and Study of Forgotten Vertebrates; Madrid Spain
| | - Juan ROFES
- Research Group Aragosaurus-IUCA, Paleontology, Earth Sciences Department; University of Zaragoza; Zaragoza Spain
- Department of Stratigraphy and Paleontology, Faculty of Sciences and Technology; University of the Basque Country; Gipuzkoa, Guipúzcoa Spain
| | - Jacint VENTURA
- Department of Animal Biology, Plant Biology and Ecology, Faculty of Biosciences; University Autonoma de Barcelona; Barcelona Spain
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Orliac MJ, Ladevèze S, Gingerich PD, Lebrun R, Smith T. Endocranial morphology of Palaeocene Plesiadapis tricuspidens and evolution of the early primate brain. Proc Biol Sci 2014; 281:20132792. [PMID: 24573845 PMCID: PMC3953834 DOI: 10.1098/rspb.2013.2792] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 02/03/2014] [Indexed: 11/12/2022] Open
Abstract
Expansion of the brain is a key feature of primate evolution. The fossil record, although incomplete, allows a partial reconstruction of changes in primate brain size and morphology through time. Palaeogene plesiadapoids, closest relatives of Euprimates (or crown-group primates), are crucial for understanding early evolution of the primate brain. However, brain morphology of this group remains poorly documented, and major questions remain regarding the initial phase of euprimate brain evolution. Micro-CT investigation of the endocranial morphology of Plesiadapis tricuspidens from the Late Palaeocene of Europe--the most complete plesiadapoid cranium known--shows that plesiadapoids retained a very small and simple brain. Plesiadapis has midbrain exposure, and minimal encephalization and neocorticalization, making it comparable with that of stem rodents and lagomorphs. However, Plesiadapis shares a domed neocortex and downwardly shifted olfactory-bulb axis with Euprimates. If accepted phylogenetic relationships are correct, then this implies that the euprimate brain underwent drastic reorganization during the Palaeocene, and some changes in brain structure preceded brain size increase and neocortex expansion during evolution of the primate brain.
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Affiliation(s)
- Maeva J. Orliac
- Institut des Sciences de l'Evolution (ISEM UMR 5554), Université Montpellier 2, CC 064, Place Eugène Bataillon, 34270 Montpellier Cedex 05, France
| | - Sandrine Ladevèze
- Muséum national d'Histoire naturelle, UMR 7207 CR2P CNRS/MNHN/UPMC, 8 rue Buffon, CP 38, 75231 Paris Cedex 05, France
| | - Philip D. Gingerich
- Museum of Paleontology, The University of Michigan, Ann Arbor, MI 48109-1079, USA
| | - Renaud Lebrun
- Institut des Sciences de l'Evolution (ISEM UMR 5554), Université Montpellier 2, CC 064, Place Eugène Bataillon, 34270 Montpellier Cedex 05, France
| | - Thierry Smith
- O.D. Earth & History of life, Royal Belgian Institute of Natural History, 29 rue Vautier, 1000 Brussels, Belgium
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Fostowicz-Frelik Ł, Meng J. Comparative morphology of premolar foramen in lagomorphs (Mammalia: Glires) and its functional and phylogenetic implications. PLoS One 2013; 8:e79794. [PMID: 24278178 PMCID: PMC3836788 DOI: 10.1371/journal.pone.0079794] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 09/25/2013] [Indexed: 12/05/2022] Open
Abstract
Lagomorphs (a group that consists of pikas, hares, rabbits and allies) are notable for their conservative morphology retained for most of their over 50 million years evolutionary history. On the other hand, their remarkable morphological uniformity partly stems from a considerable number of homoplasies in cranial and dental structures that hamper phylogenetic analyses. The premolar foramen, an opening in the palate of lagomorphs, has been characterized as an important synapomorphy of one clade, Ochotonidae (pikas). Within Lagomorpha, however, its phylogenetic distribution is much wider, the foramen being present not only in all ochotonids but also in leporids and stem taxa; its morphology and incidence also varies considerably across the order, even intraspecifically. In this study, we provide a broad survey of the taxonomic distribution of the premolar foramen in extant and fossil Lagomorpha and describe in detail the morphological variation of this character within the group. Micro-computed tomography was used to examine the hard palate and infraorbital groove morphology in Poelagus (Leporidae) and Ochotona. Scans revealed the course and contacts of the canal behind the premolar foramen and structural differences between the two crown clades. We propose that the premolar foramen has evolved independently in several lineages of Lagomorpha, and we discuss development and function of this foramen in the lagomorph skull. This study shows the importance of comprehensive studies on phylogenetically informative non-dental characters in Lagomorpha.
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Affiliation(s)
- Łucja Fostowicz-Frelik
- Division of Paleontology, American Museum of Natural History, New York, New York, United States of America
- * E-mail:
| | - Jin Meng
- Division of Paleontology, American Museum of Natural History, New York, New York, United States of America
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Ekdale EG. Comparative Anatomy of the Bony Labyrinth (Inner Ear) of Placental Mammals. PLoS One 2013; 8:e66624. [PMID: 23805251 PMCID: PMC3689836 DOI: 10.1371/journal.pone.0066624] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 05/07/2013] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Variation is a naturally occurring phenomenon that is observable at all levels of morphology, from anatomical variations of DNA molecules to gross variations between whole organisms. The structure of the otic region is no exception. The present paper documents the broad morphological diversity exhibited by the inner ear region of placental mammals using digital endocasts constructed from high-resolution X-ray computed tomography (CT). Descriptions cover the major placental clades, and linear, angular, and volumetric dimensions are reported. PRINCIPAL FINDINGS The size of the labyrinth is correlated to the overall body mass of individuals, such that large bodied mammals have absolutely larger labyrinths. The ratio between the average arc radius of curvature of the three semicircular canals and body mass of aquatic species is substantially lower than the ratios of related terrestrial taxa, and the volume percentage of the vestibular apparatus of aquatic mammals tends to be less than that calculated for terrestrial species. Aspects of the bony labyrinth are phylogenetically informative, including vestibular reduction in Cetacea, a tall cochlear spiral in caviomorph rodents, a low position of the plane of the lateral semicircular canal compared to the posterior canal in Cetacea and Carnivora, and a low cochlear aspect ratio in Primatomorpha. SIGNIFICANCE The morphological descriptions that are presented add a broad baseline of anatomy of the inner ear across many placental mammal clades, for many of which the structure of the bony labyrinth is largely unknown. The data included here complement the growing body of literature on the physiological and phylogenetic significance of bony labyrinth structures in mammals, and they serve as a source of data for future studies on the evolution and function of the vertebrate ear.
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Affiliation(s)
- Eric G. Ekdale
- Department of Biology, San Diego State University, San Diego, California, United States of America
- Department of Paleontology, San Diego Natural History Museum, San Diego, California, United States of America
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Fostowicz-Frelik Ł. Reassessment ofChadrolagusandLitolagus(Mammalia: Lagomorpha) and a New Genus of North American Eocene Lagomorph from Wyoming. AMERICAN MUSEUM NOVITATES 2013. [DOI: 10.1206/3773.2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Voloch CM, Vilela JF, Loss-Oliveira L, Schrago CG. Phylogeny and chronology of the major lineages of New World hystricognath rodents: insights on the biogeography of the Eocene/Oligocene arrival of mammals in South America. BMC Res Notes 2013; 6:160. [PMID: 23607317 PMCID: PMC3644239 DOI: 10.1186/1756-0500-6-160] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 04/11/2013] [Indexed: 11/30/2022] Open
Abstract
Background The hystricognath rodents of the New World, the Caviomorpha, are a diverse lineage with a long evolutionary history, and their representation in South American fossil record begins with their occurrence in Eocene deposits from Peru. Debates regarding the origin and diversification of this group represent longstanding issues in mammalian evolution because early hystricognaths, as well as Platyrrhini primates, appeared when South American was an isolated landmass, which raised the possibility of a synchronous arrival of these mammalian groups. Thus, an immediate biogeographic problem is posed by the study of caviomorph origins. This problem has motivated the analysis of hystricognath evolution with molecular dating techniques that relied essentially on nuclear data. However, questions remain about the phylogeny and chronology of the major caviomorph lineages. To enhance the understanding of the evolution of the Hystricognathi in the New World, we sequenced new mitochondrial genomes of caviomorphs and performed a combined analysis with nuclear genes. Results Our analysis supports the existence of two major caviomorph lineages: the (Chinchilloidea + Octodontoidea) and the (Cavioidea + Erethizontoidea), which diverged in the late Eocene. The Caviomorpha/phiomorph divergence also occurred at approximately 43 Ma. We inferred that all family-level divergences of New World hystricognaths occurred in the early Miocene. Conclusion The molecular estimates presented in this study, inferred from the combined analysis of mitochondrial genomes and nuclear data, are in complete agreement with the recently proposed paleontological scenario of Caviomorpha evolution. A comparison with recent studies on New World primate diversification indicate that although the hypothesis that both lineages arrived synchronously in the Neotropics cannot be discarded, the times elapsed since the most recent common ancestor of the extant representatives of both groups are different.
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Lagronova-Churava S, Spoutil F, Vojtechova S, Lesot H, Peterka M, Klein OD, Peterkova R. The dynamics of supernumerary tooth development are differentially regulated by Sprouty genes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2013; 320:307-20. [PMID: 23606267 DOI: 10.1002/jez.b.22502] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 02/28/2013] [Accepted: 03/01/2013] [Indexed: 11/10/2022]
Abstract
In mice, a toothless diastema separates the single incisor from the three molars in each dental quadrant. In the prospective diastema of the embryo, small rudimentary buds are found that are presumed to be rudiments of suppressed teeth. A supernumerary tooth occurs in the diastema of adult mice carrying mutations in either Spry2 or Spry4. In the case of Spry2 mutants, the origin of the supernumerary tooth involves the revitalization of a rudimentary tooth bud (called R2), whereas its origin in the Spry4 mutants is not known. In addition to R2, another rudimentary primordium (called MS) arises more anteriorly in the prospective diastema. We investigated the participation of both rudiments (MS and R2) in supernumerary tooth development in Spry2 and Spry4 mutants by comparing morphogenesis, proliferation, apoptosis, size and Shh expression in the dental epithelium of MS and R2 rudiments. Increased proliferation and decreased apoptosis were found in MS and R2 at embryonic day (ED) 12.5 and 13.5 in Spry2(-/-) embryos. Apoptosis was also decreased in both rudiments in Spry4(-/-) embryos, but the proliferation was lower (similar to WT mice), and supernumerary tooth development was accelerated, exhibiting a cap stage by ED13.5. Compared to Spry2(-/-) mice, a high number of Spry4(-/-) supernumerary tooth primordia degenerated after ED13.5, resulting in a low percentage of supernumerary teeth in adults. We propose that Sprouty genes were implicated during evolution in reduction of the cheek teeth in Muridae, and their deletion can reveal ancestral stages of murine dental evolution.
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O'Leary MA, Bloch JI, Flynn JJ, Gaudin TJ, Giallombardo A, Giannini NP, Goldberg SL, Kraatz BP, Luo ZX, Meng J, Ni X, Novacek MJ, Perini FA, Randall ZS, Rougier GW, Sargis EJ, Silcox MT, Simmons NB, Spaulding M, Velazco PM, Weksler M, Wible JR, Cirranello AL. The placental mammal ancestor and the post-K-Pg radiation of placentals. Science 2013; 339:662-7. [PMID: 23393258 DOI: 10.1126/science.1229237] [Citation(s) in RCA: 622] [Impact Index Per Article: 56.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
To discover interordinal relationships of living and fossil placental mammals and the time of origin of placentals relative to the Cretaceous-Paleogene (K-Pg) boundary, we scored 4541 phenomic characters de novo for 86 fossil and living species. Combining these data with molecular sequences, we obtained a phylogenetic tree that, when calibrated with fossils, shows that crown clade Placentalia and placental orders originated after the K-Pg boundary. Many nodes discovered using molecular data are upheld, but phenomic signals overturn molecular signals to show Sundatheria (Dermoptera + Scandentia) as the sister taxon of Primates, a close link between Proboscidea (elephants) and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats). Our tree suggests that Placentalia first split into Xenarthra and Epitheria; extinct New World species are the oldest members of Afrotheria.
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Affiliation(s)
- Maureen A O'Leary
- Department of Anatomical Sciences, School of Medicine, HSC T-8 (040), Stony Brook University, Stony Brook, NY 11794-8081, USA.
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Cox PG, Rayfield EJ, Fagan MJ, Herrel A, Pataky TC, Jeffery N. Functional evolution of the feeding system in rodents. PLoS One 2012; 7:e36299. [PMID: 22558427 PMCID: PMC3338682 DOI: 10.1371/journal.pone.0036299] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 04/04/2012] [Indexed: 11/18/2022] Open
Abstract
The masticatory musculature of rodents has evolved to enable both gnawing at the incisors and chewing at the molars. In particular, the masseter muscle is highly specialised, having extended anteriorly to originate from the rostrum. All living rodents have achieved this masseteric expansion in one of three ways, known as the sciuromorph, hystricomorph and myomorph conditions. Here, we used finite element analysis (FEA) to investigate the biomechanical implications of these three morphologies, in a squirrel, guinea pig and rat. In particular, we wished to determine whether each of the three morphologies is better adapted for either gnawing or chewing. Results show that squirrels are more efficient at muscle-bite force transmission during incisor gnawing than guinea pigs, and that guinea pigs are more efficient at molar chewing than squirrels. This matches the known diet of nuts and seeds that squirrels gnaw, and of grasses that guinea pigs grind down with their molars. Surprisingly, results also indicate that rats are more efficient as well as more versatile feeders than both the squirrel and guinea pig. There seems to be no compromise in biting efficiency to accommodate the wider range of foodstuffs and the more general feeding behaviour adopted by rats. Our results show that the morphology of the skull and masticatory muscles have allowed squirrels to specialise as gnawers and guinea pigs as chewers, but that rats are high-performance generalists, which helps explain their overwhelming success as a group.
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Affiliation(s)
- Philip G Cox
- Hull York Medical School, University of Hull, Hull, United Kingdom.
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HOOKER JERRYJ, RUSSELL DONALDE. Early Palaeogene Louisinidae (Macroscelidea, Mammalia), their relationships and north European diversity. Zool J Linn Soc 2012. [DOI: 10.1111/j.1096-3642.2011.00787.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Shockey BJ, Flynn JJ, Croft DA, Gans P, Wyss AR. New Leontiniid Notoungulata (Mammalia) from Chile and Argentina: Comparative Anatomy, Character Analysis, and Phylogenetic Hypotheses. AMERICAN MUSEUM NOVITATES 2012. [DOI: 10.1206/3737.2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Liu Y, Xu H, Yuan X, Rossiter SJ, Zhang S. Multiple Adaptive Losses of Alanine-Glyoxylate Aminotransferase Mitochondrial Targeting in Fruit-Eating Bats. Mol Biol Evol 2012; 29:1507-11. [DOI: 10.1093/molbev/mss013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Scalici M, Panchetti F. Morphological cranial diversity contributes to phylogeny in soft-furred sengis (Afrotheria, Macroscelidea). ZOOLOGY 2011; 114:85-94. [PMID: 21333512 DOI: 10.1016/j.zool.2010.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 08/30/2010] [Accepted: 09/19/2010] [Indexed: 11/28/2022]
Abstract
Despite the well-supported Macroscelidea phylogeny proposed at the end of the 1960s, several systematic arrangements have been suggested in the last 20 years, raising doubts about the phylogeny of the Macroscelidinae; sengi inter-specific relationships are still debated to this day. The main issue of concern involves the supposed Elephantulus diphyly. To solve this persisting debate about sengi phylogeny, we examined the cranium ventral surface of 13 species using geometric morphometric techniques and neighbour-joining algorithms. This study supported the idea that the ventral side of the sengi cranium has the potential to provide important signals for reconstructing the Macroscelidea phylogeny. The phylogenetic signals seemed to differentiate between two major clades in the sengi radiation. In the first clade, the two monospecific genera (Petrodromus and Macroscelides), the two African Horn species (Elephantulus revoilii and E. rufescens), and the only North African species (E. rozeti) were clustered together. The second clade includes the remnant south-central African Elephantulus species. Our results were in agreement with both mitochondrial and nuclear data, confirmed that there is no Elephantulus monophyly and highlighted the close relationship between Petrodromus and E. rozeti. It appears that all the soft-furred sengi species are organised in two evolutionary lines: an old monophyletic clade, comprising only Elephantulus species, and a new polyphyletic clade, including P. tetradactylus, M. proboscideus, and E. rozeti. This requires a taxonomic and nomenclatural rearrangement within Macroscelidinae, where the phylogenetic position of the remnant 4 (of 12) Elephantulus species has yet to be fully defined.
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Affiliation(s)
- Massimiliano Scalici
- Department of Biology, Roma Tre University, viale Guglielmo Marconi 446, 00146 Rome, Italy.
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SILCOX MARYT, BLOCH JONATHANI, BOYER DOUGM, HOUDE PETER. Cranial anatomy of Paleocene and Eocene Labidolemur kayi (Mammalia: Apatotheria), and the relationships of the Apatemyidae to other mammals. Zool J Linn Soc 2010. [DOI: 10.1111/j.1096-3642.2009.00614.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Fostowicz-Frelik Ł, Frelik GJ, Gasparik M. Morphological Phylogeny of Pikas (Lagomorpha:Ochotona), with a Description of a New Species from the Pliocene/Pleistocene Transition of Hungary. PROCEEDINGS OF THE ACADEMY OF NATURAL SCIENCES OF PHILADELPHIA 2010. [DOI: 10.1635/053.159.0107] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kraatz BP, Meng J, Weksler M, Li C. Evolutionary patterns in the dentition of duplicidentata (mammalia) and a novel trend in the molarization of premolars. PLoS One 2010; 5:e12838. [PMID: 20877465 PMCID: PMC2942898 DOI: 10.1371/journal.pone.0012838] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 08/20/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The cusp homology of Lagomorpha has long been problematic largely because their teeth are highly derived relative to their more typically tribosphenic ancestors. Within this context, the lagomorph central cusp has been particularly difficult to homologize with other tribosphenic cusps; authors have previously considered it the paracone, protocone, metacone, amphicone, or an entirely new cusp. METHODOLOGY/PRINCIPAL FINDINGS Here we present newly described fossil duplicidentates (Lagomorpha and Mimotonidae) in the context of a well-constrained phylogeny to establish a nomenclatural system for cusps based on the tribosphenic pattern. We show that the central cusp of lagomorphs is homologous with the metaconule of other mammals. We also show that the buccal acquisition of a second cusp on the premolars (molarization) within duplicidentates is atypical with respect to other mammalian lineages; within the earliest lagomorphs, a second buccal cusp is added mesially to an isolated buccal cusp. CONCLUSIONS/SIGNIFICANCE The distal shift of the 'ancestral' paracone within early duplicidentates amounts to the changing of a paracone into a metacone in these lineages. For this reason, we support a strictly topological approach to cusp names, and suggest a discontinuity in nomenclature to capture the complexity of the interplay between evolutionary history and the developmental process that have produced cusp patterns in duplicidentates.
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Affiliation(s)
- Brian P Kraatz
- Department of Anatomy, Western University of Health Sciences, Pomona, California, USA.
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Koenigswald WV, Anders U, Engels S, Schultz JA, Ruf I. Tooth Morphology in Fossil and Extant Lagomorpha (Mammalia) Reflects Different Mastication Patterns. J MAMM EVOL 2010. [DOI: 10.1007/s10914-010-9140-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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