1
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Tseng ZJ. Bending performance changes during prolonged canine eruption in saber-toothed carnivores: A case study of Smilodon fatalis. Anat Rec (Hoboken) 2024. [PMID: 38588019 DOI: 10.1002/ar.25447] [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: 12/20/2023] [Revised: 03/19/2024] [Accepted: 03/19/2024] [Indexed: 04/10/2024]
Abstract
The canine of saber-toothed predators represents one of the most specialized dental structures known. Hypotheses about the function of hypertrophied canines range from display and conspecific interaction, soft food processing, to active prey acquisition. Recent research on the ontogenetic timing of skull traits indicates the adult canine can take years to fully erupt, but the consequences of prolonged eruption on inferences of canine functional morphology are missing from current discourse and have not been quantified. Here I evaluate hypotheses about adult canine bending strength and stiffness, respectively, during eruption in the felid Smilodon fatalis. Simulated eruption sequences of three adult canines were generated from specimen models to assess shifting cross-sectional geometry properties, and bending strength and stiffness under laterally directed loads were estimated using finite element analysis. Consistent with beam theory expectations, S. fatalis canine cross-sectional geometry is optimized for increased bending strength with increased erupted height. However, canine cross-sectional geometry changes through eruption exaggerate rather than minimize lateral deflection. Spatial constraint for maximum root length from adjacent sensory structures in the maxilla and the recently identified universal power law are hypothesized to limit the growth capacity of canine anteroposterior length and, consequently, maintenance of bending stiffness through eruption. Instead, the joint presence of the deciduous and adult canines for >50% of the adult canine eruption period effectively increases canine mediolateral width and brings bending strength and stiffness estimates closer to theoretical optima. Similarly prolonged retention of deciduous canines in other sabertooths suggests dual-canine buttressing is a convergently evolved strategy to maximize bending strength and stiffness.
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Affiliation(s)
- Z Jack Tseng
- Department of Integrative Biology and Museum of Paleontology, University of California, Berkeley, California, USA
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2
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Kiel S, Goedert JL, Huynh TL, Krings M, Parkinson D, Romero R, Looy CV. Early Oligocene kelp holdfasts and stepwise evolution of the kelp ecosystem in the North Pacific. Proc Natl Acad Sci U S A 2024; 121:e2317054121. [PMID: 38227671 PMCID: PMC10823212 DOI: 10.1073/pnas.2317054121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 11/27/2023] [Indexed: 01/18/2024] Open
Abstract
Kelp forests are highly productive and economically important ecosystems worldwide, especially in the North Pacific Ocean. However, current hypotheses for their evolutionary origins are reliant on a scant fossil record. Here, we report fossil hapteral kelp holdfasts from western Washington State, USA, indicating that kelp has existed in the northeastern Pacific Ocean since the earliest Oligocene. This is consistent with the proposed North Pacific origin of kelp associated with global cooling around the Eocene-Oligocene transition. These fossils also support the hypotheses that a hapteral holdfast, rather than a discoid holdfast, is the ancestral state in complex kelps and suggest that early kelps likely had a flexible rather than a stiff stipe. Early kelps were possibly grazed upon by mammals like desmostylians, but fossil evidence of the complex ecological interactions known from extant kelp forests is lacking. The fossil record further indicates that the present-day, multi-story kelp forest had developed at latest after the mid-Miocene climate optimum. In summary, the fossils signify a stepwise evolution of the kelp ecosystem in the North Pacific, likely enabled by changes in the ocean-climate system.
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Affiliation(s)
- Steffen Kiel
- Department of Palaeobiology, Swedish Museum of Natural History, Stockholm10405, Sweden
| | - James L. Goedert
- Burke Museum of Natural History and Culture, University of Washington, Seattle, WA98195
| | - Tony L. Huynh
- School of Medicine, University of California, San Francisco, CA94143
| | - Michael Krings
- Staatliche Naturwissenschaftliche Sammlungen Bayerns-Bayerische Staatssammlung für Paläontologie und Geologie, Munich80333, Germany
- Department für Geo- und Umweltwissenschaften, Paläontologie und Geobiologie, Ludwig-Maximilians-Universität, Munich80333, Germany
| | - Dula Parkinson
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA94720
| | - Rosemary Romero
- Department of Integrative Biology, University of California, Berkeley, CA94720
| | - Cindy V. Looy
- Department of Integrative Biology, Museum of Paleontology, and Herbarium, University of California, Berkeley, CA94720
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3
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Nieto-Miranda JJ, Aguilar-Medrano R, Hernández-Camacho CJ, Peredo CM, Cruz-Escalona VH. Mechanical properties of the California sea lion (Zalophus californianus) and northern elephant seal (Mirounga angustirostris) lower jaws explain trophic plasticity. Anat Rec (Hoboken) 2023; 306:2597-2609. [PMID: 36794994 DOI: 10.1002/ar.25180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 01/31/2023] [Accepted: 01/31/2023] [Indexed: 02/17/2023]
Abstract
The fossil record of pinnipeds documents a suite of morphological changes that facilitate their ecological transition from a terrestrial to an aquatic lifestyle. Among these is the loss of the tribosphenic molar and the behavior typically associated with it in mammals: mastication. Instead, modern pinnipeds exhibit a broad range of feeding strategies that facilitate their distinct aquatic ecologies. Here, we examine the feeding morphology of two species of pinnipeds with disparate feeding ecologies: Zalophus californianus, a specialized raptorial biter, and Mirounga angustirostris, a suction specialist. Specifically, we test whether the morphology of the lower jaws facilitates trophic plasticity in feeding for either of these species. We used finite element analysis (FEA) to simulate the stresses during the opening and closing of the lower jaws in these species to explore the mechanical limits of their feeding ecology. Our simulations demonstrate that both jaws are highly resistant to the tensile stresses experienced during feeding. The lower jaws of Z. californianus experienced the maximum stress at the articular condyle and the base of the coronoid process. The lower jaws of M. angustirostris experienced the maximum stress at the angular process and were more evenly distributed throughout the body of the mandible. Surprisingly, the lower jaws of M. angustirostris were even more resistant to the stresses experienced during feeding than those of Z. californianus. Thus, we conclude that the superlative trophic plasticity of Z. californianus is driven by other factors unrelated to the mandible's tensile resistance to stress during feeding.
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Affiliation(s)
- J Jesús Nieto-Miranda
- Instituto Politécnico Nacional, Escuela Superior de Ingeniería Mecánica y Eléctrica Unidad Azcapotzalco, Ciudad de México, Mexico
| | - Rosalía Aguilar-Medrano
- Departamento de Ecología Marina, Centro de Investigación Científica y de Educación Superior de Ensenada, Ensenada, Baja California, Mexico
| | - Claudia J Hernández-Camacho
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico
| | | | - Víctor Hugo Cruz-Escalona
- Instituto Politécnico Nacional, Centro Interdisciplinario de Ciencias Marinas, La Paz, Baja California Sur, Mexico
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4
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Tamagnini D, Michaud M, Meloro C, Raia P, Soibelzon L, Tambusso PS, Varela L, Maiorano L. Conical and sabertoothed cats as an exception to craniofacial evolutionary allometry. Sci Rep 2023; 13:13571. [PMID: 37604901 PMCID: PMC10442348 DOI: 10.1038/s41598-023-40677-6] [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: 05/18/2023] [Accepted: 08/16/2023] [Indexed: 08/23/2023] Open
Abstract
Among evolutionary trends shaping phenotypic diversity over macroevolutionary scales, CREA (CRaniofacial Evolutionary Allometry) describes a tendency, among closely related species, for the smaller-sized of the group to have proportionally shorter rostra and larger braincases. Here, we used a phylogenetically broad cranial dataset, 3D geometric morphometrics, and phylogenetic comparative methods to assess the validity and strength of CREA in extinct and living felids. To test for the influence of biomechanical constraints, we quantified the impact of relative canine height on cranial shape evolution. Our results provided support to CREA at the family level. Yet, whereas felines support the rule, big cats, like Pantherinae and Machairodontinae, conform weakly if not at all with CREA predictions. Our findings suggest that Machairodontinae constitute one of the first well-supported exceptions to this biological rule currently known, probably in response to the biomechanical demands and developmental changes linked with their peculiar rostral adaptations. Our results suggest that the acquisition of extreme features concerning biomechanics, evo-devo constraints, and/or ecology is likely to be associated with peculiar patterns of morphological evolution, determining potential exceptions to common biological rules, for instance, by inducing variations in common patterns of evolutionary integration due to heterochronic changes under ratchet-like evolution.
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Affiliation(s)
- Davide Tamagnini
- Department of Biology and Biotechnologies "Charles Darwin", University of Rome "La Sapienza", Zoology Building, Viale dell'Università 32, 00185, Rome, Italy.
- Museum of Zoology, Sapienza Museum Centre, University of Rome "La Sapienza", Rome, Italy.
| | - Margot Michaud
- Evolution & Diversity Dynamics Lab, University of Liège, Liege, Belgium
| | - Carlo Meloro
- School of Biological and Environmental Sciences, Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Liverpool, UK
| | - Pasquale Raia
- Dipartimento di Scienze della Terra, dell'Ambiente e delle Risorse, University of Naples Federico II, Naples, Italy
| | - Leopoldo Soibelzon
- División Paleontología Vertebrados, Museo de La Plata, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900, La Plata, Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnicas (CONICET), Godoy Cruz 2290, C1425FQB, CABA, Argentina
| | - P Sebastián Tambusso
- Departamento de Paleontología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
- Departamento de Canelones, Servicio Académico Universitario y Centro de Estudios Paleontológicos (SAUCE-P), Universidad de la República, Santa Isabel s/n, 91500, Sauce, Uruguay
| | - Luciano Varela
- Departamento de Paleontología, Facultad de Ciencias, Universidad de la República, Iguá 4225, 11400, Montevideo, Uruguay
- Departamento de Canelones, Servicio Académico Universitario y Centro de Estudios Paleontológicos (SAUCE-P), Universidad de la República, Santa Isabel s/n, 91500, Sauce, Uruguay
| | - Luigi Maiorano
- Department of Biology and Biotechnologies "Charles Darwin", University of Rome "La Sapienza", Zoology Building, Viale dell'Università 32, 00185, Rome, Italy
- Museum of Zoology, Sapienza Museum Centre, University of Rome "La Sapienza", Rome, Italy
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5
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Weisbecker V, Beck RMD, Guillerme T, Harrington AR, Lange-Hodgson L, Lee MSY, Mardon K, Phillips MJ. Multiple modes of inference reveal less phylogenetic signal in marsupial basicranial shape compared with the rest of the cranium. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220085. [PMID: 37183893 PMCID: PMC10184248 DOI: 10.1098/rstb.2022.0085] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 12/17/2022] [Indexed: 05/16/2023] Open
Abstract
Incorporating morphological data into modern phylogenies allows integration of fossil evidence, facilitating divergence dating and macroevolutionary inferences. Improvements in the phylogenetic utility of morphological data have been sought via Procrustes-based geometric morphometrics (GMM), but with mixed success and little clarity over what anatomical areas are most suitable. Here, we assess GMM-based phylogenetic reconstructions in a heavily sampled source of discrete characters for mammalian phylogenetics-the basicranium-in 57 species of marsupial mammals, compared with the remainder of the cranium. We show less phylogenetic signal in the basicranium compared with a 'Rest of Cranium' partition, using diverse metrics of phylogenetic signal (Kmult, phylogenetically aligned principal components analysis, comparisons of UPGMA/neighbour-joining/parsimony trees and cophenetic distances to a reference phylogeny) for scaled, Procrustes-aligned landmarks and allometry-corrected residuals. Surprisingly, a similar pattern emerged from parsimony-based analyses of discrete cranial characters. The consistent results across methods suggest that easily computed metrics such as Kmult can provide good guidance on phylogenetic information in a landmarking configuration. In addition, GMM data may be less informative for intricate but conservative anatomical regions such as the basicranium, while better-but not necessarily novel-phylogenetic information can be expected for broadly characterized shapes such as entire bones. This article is part of the theme issue 'The mammalian skull: development, structure and function'.
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Affiliation(s)
- Vera Weisbecker
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5042, Australia
| | - Robin M. D. Beck
- School of Science, Engineering and Environment, University of Salford, Salford, M5 4WT, UK
| | - Thomas Guillerme
- School of Biosciences, University of Sheffield, Sheffield, S10 2TN, UK
| | | | - Leonie Lange-Hodgson
- School of Biological Sciences, University of Queensland, Saint Lucia, Queensland, 4072, Australia
| | - Michael S. Y. Lee
- College of Science and Engineering, Flinders University, Adelaide, South Australia 5042, Australia
- Earth Sciences Section, South Australian Museum, Adelaide, South Australia, 5000 Australia
| | - Karine Mardon
- Centre of Advanced Imaging, University of Queensland, Saint Lucia, Queensland, 4072, Australia
| | - Matthew J. Phillips
- School of Biology & Environmental Science, Queensland University of Technology, Brisbane, Queensland, 4000, Australia
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6
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Ruiz JV, Ferreira GS, Lautenschlager S, de Castro MC, Montefeltro FC. Different, but the same: Inferring the hunting behaviour of the hypercarnivorous bush dog (Speothos venaticus) through finite element analysis. J Anat 2023; 242:553-567. [PMID: 36485003 PMCID: PMC10008295 DOI: 10.1111/joa.13804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 11/23/2022] [Accepted: 11/25/2022] [Indexed: 12/13/2022] Open
Abstract
Cerdocyonina is a clade composed by the South-American canids in which the bush dog (Speothos venaticus) is one of the most elusive species. Known for its unique morphology within the group, this small, bear-like faced canid is the only member of the clade adapted to hypercarnivory, an almost exclusively meat-based diet currently present only in usually large, pack-hunting canids such as the grey wolf (Canis lupus). However, much of the biology of the bush dog is poorly understood, and inferences about its ecology, hunting strategies and diet are usually based on observation of captive individuals and anecdotal records, with reduced quantitative data to offer support. Here, we investigated the craniomandibular functional morphology of the bush dog through finite element analysis (FEA). FEA was employed to model the biting behaviour and to create extrinsic and intrinsic functional scenarios with different loads, corresponding to different bites used to subdue and process the prey. For comparison, the same modelling was applied to the skull of a grey wolf and a grey fox (Urocyon cinereoargenteus). Our analysis showed that the bush dog's responses to loading are more similar to the wolf's than to the fox's in most scenarios, suggesting a convergent craniomandibular functional morphology between these two hypercarnivorous species, despite their distinct phylogenetic positions and body sizes. Differences between the three taxa are noteworthy and suggested to be related to the size of the usual prey. The modelled bite force for the bush dog is relatively strong, about half of that estimated for the wolf and about 40% stronger than the fox's bite. The results strengthen with quantitative data the inferences of the bush dog as a pack-hunting predator with prey size similar to its own, such as large rodents and armadillos, being specialised in subduing and killing its prey using multiple bites. Its similarity to the wolf also confirms anecdotal accounts of predation on mammals that are much larger than itself, such as peccaries and tapirs. These data highlight the ecological specialisation of this small canid in a continent where large, pack-hunting canids are absent.
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Affiliation(s)
- Juan V Ruiz
- Laboratório de Paleontologia e Evolução de Ilha Solteira, UNESP, Ilha Solteira, Brazil.,Programa de Pós-Graduação em Biodiversidade, UNESP, São José do Rio Preto, Brazil.,Eberhard Karls University of Tübingen, Tübingen, Germany.,Senckenberg Centre for Human Evolution and Palaeoenvironment, Tübingen, Germany
| | - Gabriel S Ferreira
- Eberhard Karls University of Tübingen, Tübingen, Germany.,Senckenberg Centre for Human Evolution and Palaeoenvironment, Tübingen, Germany
| | - Stephan Lautenschlager
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Mariela C de Castro
- Laboratório de Biologia Integrativa e Conservação, Universidade Federal de Catalão, Catalão, Brazil
| | - Felipe C Montefeltro
- Laboratório de Paleontologia e Evolução de Ilha Solteira, UNESP, Ilha Solteira, Brazil
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7
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Chatar N, Fischer V, Tseng ZJ. Many-to-one function of cat-like mandibles highlights a continuum of sabre-tooth adaptations. Proc Biol Sci 2022; 289:20221627. [PMID: 36475442 PMCID: PMC9727663 DOI: 10.1098/rspb.2022.1627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cat-like carnivorans are a textbook example of convergent evolution, with distinct morphological differences between taxa with short or elongated upper canines, the latter often being interpreted as an adaptation to bite at large angles and subdue large prey. This interpretation of the sabre-tooth condition is reinforced by a reduced taxonomic sampling in some studies, often focusing on highly derived taxa or using simplified morphological models. Moreover, most biomechanical analyses focus on biting scenarios at small gapes, ideal for modern carnivora but ill-suited to test for subduction of large prey by sabre-toothed taxa. In this contribution, we present the largest three-dimensional collection-based muscle-induced biting simulations on cat-like carnivorans by running a total of 1074 analyses on 17 different taxa at three different biting angles (30°, 60° and 90°) including both morphologies. While our results show a clear adaptation of extreme sabre-toothed taxa to bite at larger angles in terms of stress distribution, other performance variables display surprising similarities between all forms at the different angles tested, highlighting a continuous rather than bipolar spectrum of hunting methods in cat-like carnivorans and demonstrating a wide functional disparity and nuances of the sabre-tooth condition that cannot simply be characterized by specialized feeding biomechanics.
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Affiliation(s)
- Narimane Chatar
- Evolution and Diversity Dynamics lab, UR Geology, Université de Liège, Building B18, Quartier Agora, Allée du Six Août 14, Liège, 4000, Belgium
| | - Valentin Fischer
- Evolution and Diversity Dynamics lab, UR Geology, Université de Liège, Building B18, Quartier Agora, Allée du Six Août 14, Liège, 4000, Belgium
| | - Z. Jack Tseng
- Department of Integrative Biology and Museum of Paleontology, University of California, Berkeley, CA 94720, USA
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8
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OUP accepted manuscript. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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9
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Tamagnini D, Meloro C, Raia P, Maiorano L. Testing the occurrence of convergence in the craniomandibular shape evolution of living carnivorans. Evolution 2021; 75:1738-1752. [PMID: 33844288 PMCID: PMC8359831 DOI: 10.1111/evo.14229] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 03/10/2021] [Accepted: 03/28/2021] [Indexed: 12/28/2022]
Abstract
Convergence consists in the independent evolution of similar traits in distantly related species. The mammalian craniomandibular complex constitutes an ideal biological structure to investigate ecomorphological dynamics and the carnivorans, due to their phenotypic variability and ecological flexibility, offer an interesting case study to explore the occurrence of convergent evolution. Here, we applied multiple pattern‐based metrics to test the occurrence of convergence in the craniomandibular shape of extant carnivorans. To this aim, we tested for convergence in many dietary groups and analyzed several cases of carnivoran convergence concerning either ecologically equivalent species or ecologically similar species of different body sizes described in the literature. Our results validate the occurrence of convergence in ecologically equivalent species in a few cases (as well as in the case of giant and red pandas), but almost never support the occurrence of convergent evolution in dietary categories of living carnivorans. Therefore, convergent evolution in this clade appears to be a rare phenomenon. This is probably the consequence of a complex interplay of one‐to‐many, many‐to‐one, and many‐to‐many relationships taking place between ecology, biomechanics, and morphology.
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Affiliation(s)
- Davide Tamagnini
- Department of Biology and Biotechnologies "Charles Darwin,", University of Rome "La Sapienza,", Rome, 00185, Italy.,Museum of Zoology, Sapienza Museum Centre, University of Rome "La Sapienza,", Rome, 00185, Italy
| | - Carlo Meloro
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool, L3 3AF, United Kingdom
| | - Pasquale Raia
- Dipartimento di Scienze della Terra, dell'Ambiente e delle Risorse, University of Naples Federico II, Napoli, 80126, Italy
| | - Luigi Maiorano
- Department of Biology and Biotechnologies "Charles Darwin,", University of Rome "La Sapienza,", Rome, 00185, Italy.,Museum of Zoology, Sapienza Museum Centre, University of Rome "La Sapienza,", Rome, 00185, Italy
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10
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Morphometric Analysis of the Mandible of Primitive Sabertoothed Felids from the late Miocene of Spain. J MAMM EVOL 2021. [DOI: 10.1007/s10914-021-09541-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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11
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Affiliation(s)
- Joseph A Cook
- Biology Department and Museum of Southwestern Biology, University of New Mexico, Albuquerque, NM, USA
| | - Jessica E Light
- Department of Wildlife and Fisheries Sciences and Biodiversity Research and Teaching Collections, Texas A&M University, College Station, TX, USA
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12
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Zhou Z, Winkler DE, Fortuny J, Kaiser TM, Marcé-Nogué J. Why ruminating ungulates chew sloppily: Biomechanics discern a phylogenetic pattern. PLoS One 2019; 14:e0214510. [PMID: 30995252 PMCID: PMC6469769 DOI: 10.1371/journal.pone.0214510] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 03/15/2019] [Indexed: 11/21/2022] Open
Abstract
There is considerable debate regarding whether mandibular morphology in ungulates primarily reflects phylogenetic affinities or adaptation to specific diet. In an effort to help resolve this debate, we use three-dimensional finite element analysis (FEA) to assess the biomechanical performance of mandibles in eleven ungulate taxa with well-established but distinct dietary preferences. We found notable differences in the magnitude and the distribution of von Mises stress between Artiodactyla and Perissodactyla, with the latter displaying lower overall stress values. Additionally, within the order Artiodactyla the suborders Ruminantia and Tylopoda showed further distinctive stress patterns. Our data suggest that a strong phylogenetic signal can be detected in biomechanical performance of the ungulate mandible. In general, Perissodactyla have stiffer mandibles than Artiodactyla. This difference is more evident between Perissodactyla and ruminant species. Perissodactyla likely rely more heavily on thoroughly chewing their food upon initial ingestion, which demands higher bite forces and greater stress resistance, while ruminants shift comminution to a later state (rumination) where less mechanical effort is required by the jaw to obtain sufficient disintegration. We therefore suggest that ruminants can afford to chew sloppily regardless of ingesta, while hindgut fermenters cannot. Additionally, our data support a secondary degree of adaptation towards specific diet. We find that mandibular morphologies reflect the masticatory demands of specific ingesta within the orders Artiodactyla and Perissodactyla. Of particular note, stress patterns in the white rhinoceros (C. simum) look more like those of a general grazer than like other rhinoceros’ taxa. Similarly, the camelids (Tylopoda) appear to occupy an intermediate position in the stress patterns, which reflects the more ancestral ruminating system of the Tylopoda.
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Affiliation(s)
- Zupeng Zhou
- School of Mechanical and Electrical Engineering, Guilin University of Electronic Technology, Guilin, China
| | - Daniela E. Winkler
- Johannes Gutenberg University Mainz, Institute of Geosciences, Mainz, Germany
| | - Josep Fortuny
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, c/ Columnes s/n, Barcelona, Spain
- Centre de Recherches en Paléontologie de Paris, Muséum National d'Histoire Naturelle, Bâtiment de Paléontologie, Paris, France
| | | | - Jordi Marcé-Nogué
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, c/ Columnes s/n, Barcelona, Spain
- Centrum für Naturkunde, University of Hamburg, Hamburg, Germany
- * E-mail:
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13
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Vermeij GJ. Comparative biogeography: innovations and the rise to dominance of the North Pacific biota. Proc Biol Sci 2018; 285:rspb.2018.2027. [PMID: 30429310 DOI: 10.1098/rspb.2018.2027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 10/29/2018] [Indexed: 11/12/2022] Open
Abstract
The North Pacific is the largest cold-water source of lineages spreading to other modern marine temperate biotas. How this status was achieved remains unclear. One hypothesis is that functional innovations of large effect, defined as departures from the norm in temperate clades and which confer competitive or defensive benefits, increase resource availability, and raise performance standards in the biota as a whole, evolved earlier and more frequently in the North Pacific than elsewhere in the temperate zone. In support of this hypothesis, phylogenetic and fossil evidence reveals 47 temperate marine innovations beginning in the latest Eocene, of which half arose in the North Pacific. Of the 22 innovations of large effect, 13 (39%) evolved in the North Pacific, including basal growth in kelps and bottom-feeding herbivory and durophagy in mammals. Temperate innovations in the Southern Hemisphere and the North Atlantic appeared later and were less consequential. Most other innovations arose in refuges where the risks of predation and competition are low. Among temperate marine biotas, the North Pacific has the highest incidence of unique innovations and the earliest origins of major breakthroughs, five of which spread elsewhere.
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Affiliation(s)
- Geerat J Vermeij
- Earth and Planetary Sciences, University of California, Davis, CA, USA
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14
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Tseng ZJ, Su DF, Wang X, White SC, Ji X. Feeding capability in the extinct giant Siamogale melilutra and comparative mandibular biomechanics of living Lutrinae. Sci Rep 2017; 7:15225. [PMID: 29123190 PMCID: PMC5680181 DOI: 10.1038/s41598-017-15391-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 10/26/2017] [Indexed: 11/09/2022] Open
Abstract
At 50 kg in estimated weight, the extinct Siamogale melilutra is larger than all living otters, and ranks among the largest fossil otters. The biomechanical capability of S. melilutra jaws as related to their large size is unknown but crucial to reconstructing the species' potentially unique ecological niche. Here we compare the mandibular biomechanics of S. melilutra using engineering-based performance measures against ten extant otter biomechanical models. Despite a wide range of feeding preferences from durophagy to piscivory, living otter species exhibit a linear relationship between mandible stiffness and volume, as expected in isometric model scaling. In contrast, S. melilutra models exhibit a six-fold increase in stiffness from expected stiffness-volume relationships calculated from extant species models. Unlike stiffness, mechanical efficiency of biting is conserved among living otters and in S. melilutra. These findings indicate that although similar to living bunodont otters in morphology and biting efficiency, jaw strength in S. melilutra far surpasses molluscivores such as sea otters and Cape clawless otters, even after accounting for size. Therefore, Siamogale represents a feeding ecomorphology with no living analog, and its giant size and high mandibular strength confer shell-crushing capability matched only by other extinct molluscivores such as the marine bear Kolponomos.
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Affiliation(s)
- Z Jack Tseng
- Department of Pathology and Anatomical Sciences, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, 14214, USA. .,Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, USA. .,Department of Vertebrate Paleontology, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California, 90007, USA.
| | - Denise F Su
- Department of Paleobotany and Paleoecology, Cleveland Museum of Natural History, 1 Wade Oval Drive, University Circle, Cleveland, Ohio, 44106, USA
| | - Xiaoming Wang
- Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024, USA.,Department of Vertebrate Paleontology, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California, 90007, USA.,Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, China
| | - Stuart C White
- School of Dentistry, University of California, Los Angeles, 10833 Le Conte Ave., Los Angeles, California, 90095, USA
| | - Xueping Ji
- Yunnan Institute of Cultural Relics and Archaeology, 15-1, Chunmingli, Chunyuan Xiaoqu, Kunming, Yunnan, 650118, China
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15
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Outomuro D, Johansson F. A potential pitfall in studies of biological shape: Does size matter? J Anim Ecol 2017; 86:1447-1457. [PMID: 28699246 DOI: 10.1111/1365-2656.12732] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 06/21/2017] [Indexed: 01/26/2023]
Abstract
The number of published studies using geometric morphometrics (GM) for analysing biological shape has increased steadily since the beginning of the 1990s, covering multiple research areas such as ecology, evolution, development, taxonomy and palaeontology. Unfortunately, we have observed that many published studies using GM do not evaluate the potential allometric effects of size on shape, which normally require consideration or assessment. This might lead to misinterpretations and flawed conclusions in certain cases, especially when size effects explain a large part of the shape variation. We assessed, for the first time and in a systematic manner, how often published studies that have applied GM consider the potential effects of allometry on shape. We reviewed the 300 most recent published papers that used GM for studying biological shape. We also estimated how much of the shape variation was explained by allometric effects in the reviewed papers. More than one-third (38%) of the reviewed studies did not consider the allometric component of shape variation. In studies where the allometric component was taken into account, it was significant in 88% of the cases, explaining up to 87.3% of total shape variation. We believe that one reason that may cause the observed results is a misunderstanding of the process that superimposes landmark configurations, i.e. the Generalized Procrustes Analysis, which removes isometric effects of size on shape, but not allometric effects. Allometry can be a crucial component of shape variation. We urge authors to address, and report, size effects in studies of biological shape. However, we do not propose to always remove size effects, but rather to evaluate the research question with and without the allometric component of shape variation. This approach can certainly provide a thorough understanding of how much size contributes to the observed shaped variation.
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Affiliation(s)
- David Outomuro
- Section for Animal Ecology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Frank Johansson
- Section for Animal Ecology, Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
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16
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A biomechanical approach to understand the ecomorphological relationship between primate mandibles and diet. Sci Rep 2017; 7:8364. [PMID: 28827696 PMCID: PMC5567063 DOI: 10.1038/s41598-017-08161-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/07/2017] [Indexed: 11/30/2022] Open
Abstract
The relationship between primate mandibular form and diet has been previously analysed by applying a wide array of techniques and approaches. Nonetheless, most of these studies compared few species and/or infrequently aimed to elucidate function based on an explicit biomechanical framework. In this study, we generated and analysed 31 Finite Element planar models of different primate jaws under different loading scenarios (incisive, canine, premolar and molar bites) to test the hypothesis that there are significant differences in mandibular biomechanical performance due to food categories and/or food hardness. The obtained stress values show that in primates, hard food eaters have stiffer mandibles when compared to those that rely on softer diets. In addition, we find that folivores species have the weakest jaws, whilst omnivores have the strongest mandibles within the order Primates. These results are highly relevant because they show that there is a strong association between mandibular biomechanical performance, mandibular form, food hardness and diet categories and that these associations can be studied using biomechanical techniques rather than focusing solely on morphology.
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