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Xiong Y, Rozzi R, Zhang Y, Fan L, Zhao J, Li D, Yao Y, Xiao H, Liu J, Zeng X, Xu H, Jiang Y, Lei F. Convergent evolution toward a slow pace of life predisposes insular endotherms to anthropogenic extinctions. SCIENCE ADVANCES 2024; 10:eadm8240. [PMID: 38996028 PMCID: PMC11244536 DOI: 10.1126/sciadv.adm8240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 06/10/2024] [Indexed: 07/14/2024]
Abstract
Island vertebrates have evolved a number of morphological, physiological, and life history characteristics that set them apart from their mainland relatives. However, to date, the evolution of metabolism and its impact on the vulnerability to extinction of insular vertebrates remains poorly understood. This study used metabolic data from 2813 species of tetrapod vertebrates, including 695 ectothermic and 2118 endothermic species, to reveal that island mammals and birds evolved convergent metabolic strategies toward a slow pace of life. Insularity was associated with shifts toward slower metabolic rates and greater generation lengths in endotherms, while insularity just drove the evolution of longer generation lengths in ectotherms. Notably, a slow pace of life has exacerbated the extinction of insular endemic species in the face of anthropogenic threats. These findings have important implications for understanding physiological adaptations associated with the island syndrome and formulating conservation strategies across taxonomic groups with different metabolic modes.
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Affiliation(s)
- Ying Xiong
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Roberto Rozzi
- Zentralmagazin Naturwissenschaftlicher Sammlungen, Martin Luther University Halle-Wittenberg, 06108 Halle (Saale), Germany
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, 10115 Berlin, Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstraße 4, 04103 Leipzig, Germany
| | - Yizhou Zhang
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Liqing Fan
- Key Laboratory of Forest Ecology in Tibet Plateau, Tibet Agricultural & Animal Husbandry University, Ministry of Education, Nyingchi 860000, China
| | - Jidong Zhao
- Shaanxi Key Laboratory of Qinling Ecological Security, Shaanxi Institude of Zoology, Xi’an 710000, China
| | - Dongming Li
- Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Sciences, Hebei Normal University, Shijiazhuang 050024, China
| | - Yongfang Yao
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Hongtao Xiao
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Jing Liu
- Ministry of Education Key Laboratory for Ecology of Tropical Islands, Key Laboratory of Tropical Animal and Plant Ecology of Hainan Province, College of Life Sciences, Hainan Normal University, Haikou 571158, China
| | - Xianyin Zeng
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Huailiang Xu
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Yanzhi Jiang
- Department of Zoology, College of Life science, Sichuan Agricultural University, Ya’an 625000, China
| | - Fumin Lei
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
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2
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Martino R, Zanolli C, Fidalgo D, Pandolfi L. Talking heads: disentangling the shape changes of the large extant hippopotamus during its ontogenetic development. Integr Zool 2024. [PMID: 38816905 DOI: 10.1111/1749-4877.12850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
Using a 3D geometric morphometrics approach, we shed light on the major changes during the ontogenetic development of Hippopotamus amphibius. The main shift in the shape variability of cranial elements in juveniles can probably be related to the interruption of suckling. A less stressed shift in the cranial variability can probably be related to the attainment of sexual maturity. Semilandmarks and landmarks are powerful tools to discriminate between extant species and, therefore, this technique will be particularly useful in the future to study fossil ones as well.
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Affiliation(s)
- Roberta Martino
- Department of Earth Sciences, GeoBioTec, School of Science and Technology, FCT NOVA, Universidade NOVA de Lisboa, Caparica, Portugal
- Museu da Lourinhã, Lourinhã, Portugal
| | | | - Darío Fidalgo
- Department of Palaeobiology, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain
| | - Luca Pandolfi
- Dipartimento di Scienze, Università della Basilicata, Potenza, Italy
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3
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Pestana C, de Sousa AA, Todorov OS, Beaudet A, Benoit J. Evolutionary history of hominin brain size and phylogenetic comparative methods. PROGRESS IN BRAIN RESEARCH 2023; 275:217-232. [PMID: 36841569 DOI: 10.1016/bs.pbr.2022.12.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
An absolutely and relatively large brain has traditionally been viewed as a distinctive characteristic of the Homo genus, with anatomically modern humans presented at the apex of a long line of progressive increases in encephalization. Many studies continue to focus attention on increasing brain size in the Homo genus, while excluding measures of absolute and relative brain size of more geologically recent, smaller brained, hominins such as Homo floresiensis, and Homo naledi and smaller brained Homo erectus specimens. This review discusses the benefits of using phylogenetic comparative methods to trace the diverse changes in hominin brain evolution and the drawbacks of not doing so.
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Affiliation(s)
- Christopher Pestana
- Evolutionary Studies Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
| | | | - Orlin S Todorov
- School of Natural Sciences, Macquarie University, Sydney, NSW, Australia
| | - Amélie Beaudet
- Department of Archaeology, University of Cambridge, Cambridge, United Kingdom; School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, Johannesburg, South Africa; Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Julien Benoit
- Evolutionary Studies Institute, School of Geosciences, University of the Witwatersrand, Johannesburg, South Africa
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Pérez-Claros JA, Palmqvist P. Heterochronies and allometries in the evolution of the hominid cranium: a morphometric approach using classical anthropometric variables. PeerJ 2022; 10:e13991. [PMID: 36042865 PMCID: PMC9420405 DOI: 10.7717/peerj.13991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 08/11/2022] [Indexed: 01/19/2023] Open
Abstract
This article studies the evolutionary change of allometries in the relative size of the two main cranial modules (neurocranium and splanchnocranium) in the five living hominid species and a diverse sample of extinct hominins. We use six standard craniometric variables as proxies for the length, width and height of each cranial module. Factor analysis and two-block partial least squares (2B-PLS) show that the great apes and modern humans share a pervasive negative ontogenetic allometry in the neurocranium and a positive one in the splanchnocranium. This developmental constraint makes it possible to interpret the cranial heterochronies in terms of ontogenetic scaling processes (i.e., extensions or truncations of the ancestral ontogenetic trajectory) and lateral transpositions (i.e., parallel translations of the entire trajectory starting from a different shape for a given cranial size). We hypothesize that ontogenetic scaling is the main evolutionary modality in the australopithecines while in the species of Homo it is also necessary to apply transpositions. Both types of processes are coordinated in Homo, which result in an evolutionary trend toward an increase in brain size and in the degree of paedomorphosis from the earliest habilines.
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5
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Génin F, Mazza PP, Pellen R, Rabineau M, Aslanian D, Masters JC. Co-evolution assists geographic dispersal: the case of Madagascar. Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blac090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Interspecific associations may limit the dispersal of individual species, but may also facilitate it when entire co-evolved systems expand their geographic ranges. We tested the recent proposal that episodic land bridges linked Africa and Madagascar at three stages during the Cenozoic by comparing divergence estimates of Madagascar’s angiosperm taxa with their dispersal mechanisms. Plants that rely on gravity for seed dispersal indicate at least two episodes of land connection between Africa and Madagascar, in the Early Palaeocene and Early Oligocene. Seed dispersal by strepsirrhine primates possibly evolved in the Palaeocene, with the divergence of at least one endemic Malagasy angiosperm genus, Burasaia (Menispermaceae). This genus may have facilitated the lemur colonization of Madagascar. Frugivory, nectarivory and gummivory probably generalized in the Oligocene, with the co-evolution of modern lemurs and at least 10 new Malagasy angiosperm families. In the Late Miocene, more angiosperms were probably brought from Africa by birds via a discontinuous land connection, and radiated on Madagascar in diffuse association with birds (asities) and dwarf nocturnal lemurs (cheirogaleids). During the same connective episode, Madagascar was probably colonized by hippopotamuses, which both followed and re-seeded a variety of plants, forming the grassy Uapaca ‘tapia’ forest and ericoid ‘savoka’ thicket.
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Affiliation(s)
- Fabien Génin
- African Primate Initiative for Ecology and Speciation (APIES) and Africa Earth Observatory Network (AEON), Earth Stewardship Science Research Institute, Nelson Mandela University , Gqeberha (Port Elizabeth) , South Africa
| | - Paul Pa Mazza
- Department of Earth Sciences, University of Florence , via La Pira, Florence , Italy
| | - Romain Pellen
- African Primate Initiative for Ecology and Speciation (APIES) and Africa Earth Observatory Network (AEON), Earth Stewardship Science Research Institute, Nelson Mandela University , Gqeberha (Port Elizabeth) , South Africa
| | - Marina Rabineau
- CNRS, Institut Français de Recherche pour l’Exploration de la Mer (IFREMER ), UMR 6538 Geo-Ocean, IUEM, Univ Brest, Plouzané , France
| | - Daniel Aslanian
- CNRS, Institut Français de Recherche pour l’Exploration de la Mer (IFREMER ), UMR 6538 Geo-Ocean, IUEM, Univ Brest, Plouzané , France
| | - Judith C Masters
- African Primate Initiative for Ecology and Speciation (APIES) and Africa Earth Observatory Network (AEON), Earth Stewardship Science Research Institute, Nelson Mandela University , Gqeberha (Port Elizabeth) , South Africa
- Department of Botany & Zoology, Stellenbosch University , Stellenbosch , South Africa
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6
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Heldstab SA, Isler K, Graber SM, Schuppli C, van Schaik CP. The economics of brain size evolution in vertebrates. Curr Biol 2022; 32:R697-R708. [PMID: 35728555 DOI: 10.1016/j.cub.2022.04.096] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Across the animal kingdom, we see remarkable variation in brain size. This variation has even increased over evolutionary time. Traditionally, studies aiming to explain brain size evolution have looked at the fitness benefits of increased brain size in relation to its increased cognitive performance in the social and/or ecological domain. However, brains are among the most energetically expensive tissues in the body and also require an uninterrupted energy supply. If not compensated, these energetic demands inevitably lead to a reduction in energy allocation to other vital functions. In this review, we summarize how an increasing number of studies show that to fully comprehend brain size evolution and the large variation in brain size across lineages, it is important to look at the economics of brains, including the different pathways through which the high energetic costs of brains can be offset. We further show how numerous studies converge on the conclusion that cognitive abilities can only drive brain size evolution in vertebrate lineages where they result in an improved energy balance through favourable ecological preconditions. Cognitive benefits that do not directly improve the organism's energy balance can only be selectively favoured when they produce such large improvements in reproduction or survival that they outweigh the negative energetic effects of the large brain.
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Affiliation(s)
- Sandra A Heldstab
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Development and Evolution of Cognition Research Group, Max Planck Institute of Animal Behavior, Bücklestrasse 5a, 78467 Konstanz, Germany.
| | - Karin Isler
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Sereina M Graber
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Caroline Schuppli
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Development and Evolution of Cognition Research Group, Max Planck Institute of Animal Behavior, Bücklestrasse 5a, 78467 Konstanz, Germany
| | - Carel P van Schaik
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Comparative Socioecology Group, Max Planck Institute of Animal Behavior, Bücklestrasse 5a, 78467 Konstanz, Germany; Department of Evolutionary Biology and Environmental Science, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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7
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Csiki-Sava Z, Vremir M, Meng J, Vasile Ş, Brusatte SL, Norell MA. Spatial and Temporal Distribution of the Island-Dwelling Kogaionidae (Mammalia, Multituberculata) in the Uppermost Cretaceous of Transylvania (Western Romania). BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2022. [DOI: 10.1206/0003-0090.456.1.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Zoltán Csiki-Sava
- Laboratory of Paleontology, Faculty of Geology and Geophysics, and Center for Risk Studies, Space Modeling and Dynamics of Terrestrial and Coastal Systems, University of Bucharest
| | - Mátyás Vremir
- Deceased; formerly Department of Natural Sciences, Transylvanian Museum Society, Cluj-Napoca, Romania
| | - Jin Meng
- Division of Paleontology, American Museum of Natural History, New York
| | - Ştefan Vasile
- Laboratory of Paleontology, Faculty of Geology and Geophysics, and Center for Risk Studies, Space Modeling and Dynamics of Terrestrial and Coastal Systems, University of Bucharest
| | | | - Mark A. Norell
- Division of Paleontology, American Museum of Natural History, New York
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8
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Gavriilidi I, De Meester G, Van Damme R, Baeckens S. How to behave when marooned: the behavioural component of the island syndrome remains underexplored. Biol Lett 2022; 18:20220030. [PMID: 35440235 PMCID: PMC9039784 DOI: 10.1098/rsbl.2022.0030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Animals on islands typically depart from their mainland relatives in assorted aspects of their biology. Because they seem to occur in concert, and to some extent evolve convergently in disparate taxa, these changes are referred to as the ‘island syndrome’. While morphological, physiological and life-history components of the island syndrome have received considerable attention, much less is known about how insularity affects behaviour. In this paper, we argue why changes in personality traits and cognitive abilities can be expected to form part of the island syndrome. We provide an overview of studies that have compared personality traits and cognitive abilities between island and mainland populations, or among islands. Overall, the pickings are remarkably slim. There is evidence that animals on islands tend to be bolder than on the mainland, but effects on other personality traits go either way. The evidence for effects of insularity on cognitive abilities or style is highly circumstantial and very mixed. Finally, we consider the ecological drivers that may induce such changes, and the mechanisms through which they might occur. We conclude that our knowledge of the behavioural and cognitive responses to island environments remains limited, and we encourage behavioural biologists to make more use of these ‘natural laboratories for evolution’.
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Affiliation(s)
- Ioanna Gavriilidi
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium.,Section of Zoology and Marine Biology, Department of Biology, National and Kapodistrian University of Athens, Greece
| | - Gilles De Meester
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Raoul Van Damme
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium
| | - Simon Baeckens
- Functional Morphology Lab, Department of Biology, University of Antwerp, Wilrijk, Belgium.,Evolution and Optics of Nanostructures Lab, Department of Biology, Ghent University, Ghent, Belgium
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9
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Hansford JP, Turvey ST. Dietary isotopes of Madagascar's extinct megafauna reveal holocene browsing and grazing guilds. Biol Lett 2022; 18:20220094. [PMID: 35414222 PMCID: PMC9006009 DOI: 10.1098/rsbl.2022.0094] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Megafauna play a disproportionate role in developing and maintaining their biomes, by regulating plant dispersal, community structure and nutrient cycling. Understanding the ecological roles of extinct megafaunal communities, for example through dietary reconstruction using isotope analysis, is necessary to determine pre-human states and set evidence-based restoration goals. We use δ13C and δ15N isotopic analyses to reconstruct Holocene feeding guilds in Madagascar's extinct megaherbivores, which included elephant birds, hippopotami and giant tortoises that occurred across multiple habitats and elevations. We compare isotopic data from seven taxa and two elephant bird eggshell morphotypes against contemporary regional floral baselines to infer dietary subsistence strategies. Most taxa show high consumption of C3 and/or CAM plants, providing evidence of widespread browsing ecology. However, Aepyornis hildebrandti, an elephant bird restricted to the central highlands region, has isotope values with much higher δ13C values than other taxa. This species is interpreted as having obtained up to 48% of its diet from C4 grasses. These findings provide new evidence for distinct browsing and grazing guilds in Madagascar's Holocene megaherbivore fauna, with implications for past regional distribution of ecosystems dominated by endemic C4 grasses.
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Affiliation(s)
- James P Hansford
- Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK.,Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA.,School of Ocean and Earth Science, National Oceanography Centre, University of Southampton, Southampton, UK
| | - Samuel T Turvey
- Institute of Zoology, Zoological Society of London, Regent's Park, London NW1 4RY, UK
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Zedda M, Brunetti A, Palombo MR. First Attempt to Infer Sound Hearing and Its Paleoenvironmental Implications in the Extinct Insular Canid Cynotherium sardous Studiati, 1857 (Sardinia, Italy). Animals (Basel) 2022; 12:ani12070833. [PMID: 35405823 PMCID: PMC8996844 DOI: 10.3390/ani12070833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/10/2022] [Accepted: 03/13/2022] [Indexed: 11/25/2022] Open
Abstract
Simple Summary The microtomographic approach allows nondestructive acquisition of anatomical details of the bone labyrinth that houses the inner ear. The petrosal bone can be a gold mine of information for a variety of questions in different research fields, including taxonomic, behavioral, and genetic studies. The semicircular canals provide information on head posture and locomotor ability, whereas the cochlea provides data on hearing ability. The petrosal bone is the hardest structure in the skeleton and could be well preserved in fossil specimens. As a result, it is becoming more and more popular in current archaeological and paleontological studies. In this study, petrosal microtomographic analysis was applied for the first time to Cynotherium sardous, a highly modified endemic canid that inhabited Sardinia during the Middle to Late Pleistocene. Indications about its hearing ability may provide interesting insights to better understand the new lifestyle and behavior this canid acquired during the long evolutionary process it underwent in the peculiar insular ecosystem with a depleted fauna. The poor hearing and echolocalization capabilities of Cynotherium sardous would have been the outcome of reduced competition pressure due to the absence of predators and the abundance of prey, such as the large ochotonid Prolagus sardus, while the high-frequency hearing could be interpreted as an adaptation to detect sounds emitted by its preferred prey. Abstract This is the first study on the bony labyrinth of Cynotherium sardous, an intriguing extinct canid that inhabited Sardinia in the late Middle and Late Pleistocene. The morphological features of the cochlea indicate that C. sardous had a lower number of cochlear turns (2.25) than all extant canids. This feature, as well as the reduced length of the spiral canal, the cochlear curvature rate, and the narrow basal membrane, indicates that C. sardous had poor hearing abilities limited to high-frequency sounds with a low limit of 250 Hz and poor echolocalization skills. From the data available, it is not possible to infer whether C. sardous was unable to echolocalize its prey and relied on other senses (e.g., smell and sight) to locate them or whether the acoustic range of C. sardous was specialized for identifying the sounds produced by its most common prey to transmit signals for predator warnings or group communication. All things considered, the results obtained confirm the utility of cochlea morphological studies in reconstructing the hearing abilities of this species and in providing some suggestions about its ethology, but they fall short of providing any new sound evidence regarding the ecological role of C. sardous in the Late Pleistocene Sardinian ecosystem.
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Affiliation(s)
- Marco Zedda
- Department of Veterinary Medicine, University of Sassari, 07100 Sassari, Italy
- Correspondence: ; Tel.: +39-079-229-583
| | - Antonio Brunetti
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy;
| | - Maria Rita Palombo
- CNR-IGAG c/o Department of Earth Sciences, Sapienza University, 00185 Rome, Italy;
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Perez-Martinez CA, Leal M. Lizards as models to explore the ecological and neuroanatomical correlates of miniaturization. BEHAVIOUR 2021. [DOI: 10.1163/1568539x-bja10104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Abstract
Extreme body size reductions bring about unorthodox anatomical arrangements and novel ways in which animals interact with the environment. Drawing from studies of vertebrates and invertebrates, we provide a theoretical framework for miniaturization to inform hypotheses using lizards as a study system. Through this approach, we demonstrate the repeated evolution of miniaturization across 11 families and a tendency for miniaturized species to occupy terrestrial microhabitats, possibly driven by physiological constraints. Differences in gross brain morphology between two gecko species demonstrate a proportionally larger telencephalon and smaller olfactory bulbs in the miniaturized species, though more data are needed to generalize this trend. Our study brings into light the potential contributions of miniaturized lizards to explain patterns of body size evolution and its impact on ecology and neuroanatomy. In addition, our findings reveal the need to study the natural history of miniaturized species, particularly in relation to their sensory and physiological ecology.
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Affiliation(s)
| | - Manuel Leal
- Division of Biological Sciences, University of Missouri, Columbia, MO 65201, USA
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12
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Cordero GA. Disentangling the correlated evolution of body size, life history, and ontogeny in miniaturized chelydroid turtles. Evol Dev 2021; 23:439-458. [PMID: 34037309 DOI: 10.1111/ede.12386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/27/2021] [Accepted: 05/03/2021] [Indexed: 12/21/2022]
Abstract
Organismal miniaturization is defined by a reduction in body size relative to a large ancestor. In vertebrate animals, miniaturization is achieved by suppressing the energetics of growth. However, this might interfere with reproductive strategies in egg-laying species with limited energy budgets for embryo growth and differentiation. In general, the extent to which miniaturization coincides with alterations in animal development remains obscure. To address the interplay among body size, life history, and ontogeny, miniaturization in chelydroid turtles was examined. The analyses corroborated that miniaturization in the Chelydroidea clade is underlain by a dampening of the ancestral growth trajectory. There were no associated shifts in the early sequence of developmental transformations, though the relative duration of organogenesis was shortened in miniaturized embryos. The size of eggs, hatchlings, and adults was positively correlated within Chelydroidea. A phylogenetically broader exploration revealed an alternative miniaturization mode wherein exceptionally large hatchlings grow minimally and thus attain diminutive adult sizes. Lastly, it is shown that miniaturized Chelydroidea turtles undergo accelerated ossification coupled with a ~10% reduction in shell bones. As in other vertebrates, the effects of miniaturization were not systemic, possibly owing to opposing functional demands and tissue geometric constraints. This underscores the integrated and hierarchical nature of developmental systems.
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Affiliation(s)
- Gerardo A Cordero
- Department of Geosciences, University of Tübingen, Tübingen, Germany
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13
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Rajabizadeh M, Adriaens D, De Kegel B, Avci A, Ilgaz Ç, Herrel A. Body size miniaturization in a lineage of colubrid snakes: Implications for cranial anatomy. J Anat 2021; 238:131-145. [PMID: 32790082 PMCID: PMC7754943 DOI: 10.1111/joa.13293] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 01/03/2023] Open
Abstract
As body size strongly determines the biology of an organism at all levels, it can be expected that miniaturization comes with substantial structural and functional constraints. Dwarf snakes of the genus Eirenis are derived from big, surface-dwelling ancestors, considered to be similar to those of the sister genus Dolichophis. To better understand the structural implications of miniaturization on the feeding apparatus in Eirenis, the morphology of the cranial musculoskeletal system of Dolichophis schmidti was compared with that of the miniature Eirenis punctatolineatus and E. persicus using high-resolution µCT data. The gape index was compared between D. schmidti and 14 Eirenis species. Our results show a relatively increased neurocranium size and decreased maximal jaw muscle force in E. persicus, compared with the D. schmidti, and an intermediate situation in E. punctatolineatus. A significant negative allometry in gape index relative to body size is observed across the transition from the Dolichophis to Pediophis and Eirenis subgenera. However, the gape index relative to head size showed a significant negative allometry only across the transition from the Dolichophis to Pseudocyclophis subgenus. In Dolichophis-Eirenis dwarfing lineages, different structural patterns are observed through miniaturization, indicating that overcoming the challenge of miniaturization has achieved via different adaptations.
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Affiliation(s)
- Mahdi Rajabizadeh
- UMR7179 CNRS/MNHNDépartement `Adaptations du vivantMuseum National d'Histoire NaturelleParisFrance,Department of BiodiversityInstitute of Science and High Technology and Environmental SciencesGraduate University of Advanced TechnologyKermanIran
| | - Dominique Adriaens
- Department of BiologyEvolutionary Morphology of VertebratesGhent UniversityGhentBelgium
| | - Barbara De Kegel
- Department of BiologyEvolutionary Morphology of VertebratesGhent UniversityGhentBelgium
| | - Aziz Avci
- Department of BiologyFaculty of Science and ArtsAydın Adnan Menderes UniversityAydýnTurkey
| | - Çetin Ilgaz
- Department of BiologyFaculty of ScienceDokuz Eylül UniversityİzmirTurkey
| | - Anthony Herrel
- UMR7179 CNRS/MNHNDépartement `Adaptations du vivantMuseum National d'Histoire NaturelleParisFrance,Department of BiologyEvolutionary Morphology of VertebratesGhent UniversityGhentBelgium,Department of BiologyFunctional MorphologyUniversity of AntwerpAntwerpBelgium
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14
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Castiglione S, Serio C, Piccolo M, Mondanaro A, Melchionna M, Di Febbraro M, Sansalone G, Wroe S, Raia P. The influence of domestication, insularity and sociality on the tempo and mode of brain size evolution in mammals. Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa186] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
The ability to develop complex social bonds and an increased capacity for behavioural flexibility in novel environments have both been forwarded as selective forces favouring the evolution of a large brain in mammals. However, large brains are energetically expensive, and in circumstances in which selective pressures are relaxed, e.g. on islands, smaller brains are selected for. Similar reasoning has been offered to explain the reduction of brain size in domestic species relative to their wild relatives. Herein, we assess the effect of domestication, insularity and sociality on brain size evolution at the macroevolutionary scale. Our results are based on analyses of a 426-taxon tree, including both wild species and domestic breeds. We further develop the phylogenetic ridge regression comparative method (RRphylo) to work with discrete variables and compare the rates (tempo) and direction (mode) of brain size evolution among categories within each of three factors (sociality, insularity and domestication). The common assertion that domestication increases the rate of brain size evolution holds true. The same does not apply to insularity. We also find support for the suggested but previously untested hypothesis that species living in medium-sized groups exhibit faster rates of brain size evolution than either solitary or herding taxa.
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Affiliation(s)
- Silvia Castiglione
- Department of Earth Sciences, Environment and Resources, University of Naples Federico II, Napoli, Italy
| | - Carmela Serio
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK
| | - Martina Piccolo
- Department of Earth Sciences, Environment and Resources, University of Naples Federico II, Napoli, Italy
| | - Alessandro Mondanaro
- Department of Earth Sciences, Environment and Resources, University of Naples Federico II, Napoli, Italy
- Department of Earth Sciences, University of Florence, Firenze, Italy
| | - Marina Melchionna
- Department of Earth Sciences, Environment and Resources, University of Naples Federico II, Napoli, Italy
| | - Mirko Di Febbraro
- Department of Biosciences and Territory, University of Molise, C. da Fonte Lappone, 15, Pesche, IS, Italy
| | - Gabriele Sansalone
- Function, Evolution & Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Stephen Wroe
- Function, Evolution & Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Pasquale Raia
- Department of Earth Sciences, Environment and Resources, University of Naples Federico II, Napoli, Italy
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15
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Young CB. Static allometry of a small-bodied omnivore: body size and limb scaling of an island fox and inferences for Homo floresiensis. J Hum Evol 2020; 149:102899. [PMID: 33137549 DOI: 10.1016/j.jhevol.2020.102899] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 10/01/2020] [Accepted: 10/01/2020] [Indexed: 11/18/2022]
Abstract
Island dwarfing is a paraphyletic adaptation across numerous mammalian genera. From mammoths to foxes, extreme body size reduction is shared by diverse organisms that migrate to an island environment. Because it largely occurs owing to ecological variables, not phylogenetic ones, skeletal characters in a dwarfed taxon compared with its ancestor may appear abnormal. As a result, allometric patterns between body size and morphological traits may differ for an island dwarf compared with its ancestor. The diminutive Late Pleistocene hominin, Homo floresiensis, displays a unique character suite that is outside of the normal range of variation for any extinct or extant hominin species. To better explain these as ecological traits due to island dwarfing, this research looks at how dwarfing on islands influences limb scaling and proportions in an organism in a similar ecological niche as H. floresiensis. Here, I analyze absolute limb lengths and static allometry of limb lengths regressed on predicted body mass of dwarfed island foxes and their nondwarfed relatives. Dwarfed island foxes have significantly smaller intercepts but steeper slopes of all limb elements regressed on predicted body mass than the mainland gray fox. These allometric alterations produce limbs in the island fox that are significantly shorter than predicted for a nondwarfed gray fox of similar body mass. In addition, the humerofemoral, intermembral, and brachial indices are significantly different. These results provide a novel model for understanding skeletal variation of island endemic forms. Unique body size and proportions of H. floresiensis are plausible as ecological adaptations and likely not examples of symplesiomorphies with Australopithecus sp. Caution should be exerted when comparing an island dwarf with a closely related species as deviations from allometric expectations may be common.
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Affiliation(s)
- Colleen B Young
- University of Missouri, Department of Anthropology, 112 Swallow Hall, Columbia, MO, 65203, USA.
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16
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Fontoura E, Ferreira JD, Bubadué J, Ribeiro AM, Kerber L. Virtual brain endocast of Antifer (Mammalia: Cervidae), an extinct large cervid from South America. J Morphol 2020; 281:1223-1240. [PMID: 32815595 DOI: 10.1002/jmor.21243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/23/2020] [Accepted: 07/17/2020] [Indexed: 01/22/2023]
Abstract
A diverse fossil record of Cervidae (Mammalia) has been documented in the South American Pleistocene, when these animals arrived during the Great American Biotic Interchange. Using computed tomography-scanning techniques, it is possible to access the endocranial morphology of extinct species. Here, we studied the brain endocast of the extinct late Pleistocene cervid Antifer ensenadensis from southern Brazil, one of the largest forms that lived on this continent, using comparative morphology, geometric morphometrics, and encephalization quotients. The analyzed endocasts demonstrate that A. ensenadensis had a gyrencephalic brain, showing a prominent longitudinal sinus (=sagittal superior sinus), which is also observed in the large South American cervid Blastocerus dichotomus. The encephalization quotient is within the variation of extant cervids, suggesting maintenance of the pattern of encephalization from at least the late Pleistocene. Geometric morphometric analysis suggested a clear and linear allometric trend between brain endocast size and shape, and highlights A. ensenadensis as an extreme form within the analyzed cervids regarding brain morphology.
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Affiliation(s)
- Emmanuelle Fontoura
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil.,Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, São João do Polêsine, Brazil
| | - José Darival Ferreira
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil.,Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, São João do Polêsine, Brazil
| | - Jamile Bubadué
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil.,Laboratório de Ciências Ambientais, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Brazil
| | - Ana Maria Ribeiro
- Seção de Paleontologia, Museu de Ciências Naturais, Secretaria do Meio Ambiente e Infraestrutura, Porto Alegre, Brazil
| | - Leonardo Kerber
- Programa de Pós-Graduação em Biodiversidade Animal, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, Brazil.,Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, São João do Polêsine, Brazil.,Museu Paraense Emílio Goeldi, Coordenação de Ciências da Terra e Ecologia, Belém, Brazil
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17
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Skeleton of a Cretaceous mammal from Madagascar reflects long-term insularity. Nature 2020; 581:421-427. [DOI: 10.1038/s41586-020-2234-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/26/2020] [Indexed: 11/09/2022]
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18
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Ferreira JD, Negri FR, Sánchez-Villagra MR, Kerber L. Small within the largest: brain size and anatomy of the extinct
Neoepiblema acreensis
, a giant rodent from the Neotropics. Biol Lett 2020. [PMCID: PMC7058952 DOI: 10.1098/rsbl.2019.0914] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The ecomorphological diversity of caviomorph rodents in South America included giant forms, such as the chinchilloid Neoepiblema acreensis from the Upper Miocene of Brazil. The evolution of the brain anatomy and size of these animals can be now studied with non-invasive imaging techniques and exceptional fossils. Caviomorphs show diversity in the traits of the olfactory bulbs, cerebrum, cerebellum, cranial nerves, and blood vessels. Neoepiblema acreensis had a gyrencephalic brain, with an expansion of the frontal lobe, lacking an evident paraflocculus. Compared to the predictions based on extant taxa, even when considering taphonomical effects, N. acreensis, a rodent that weighted almost 80 kg, had a very low encephalization quotient compared to other rodents. The adaptive value of a low energetic cost and other ecological factors could explain the presence of a small brain in this giant rodent––a pattern we also hypothesize for other Neogene giant rodents.
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Affiliation(s)
- José D. Ferreira
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, Brazil
| | - Francisco R. Negri
- Laboratório de Paleontologia, Campus Floresta, Universidade Federal do Acre, Cruzeiro do Sul, Acre, Brazil
| | | | - Leonardo Kerber
- Programa de Pós-Graduação em Biodiversidade Animal, Universidade Federal de Santa Maria, Santa Maria, Brazil
- Centro de Apoio à Pesquisa Paleontológica da Quarta Colônia (CAPPA), Universidade Federal de Santa Maria, São João do Polêsine, Brazil
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19
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Ni X, Flynn JJ, Wyss AR, Zhang C. Cranial endocast of a stem platyrrhine primate and ancestral brain conditions in anthropoids. SCIENCE ADVANCES 2019; 5:eaav7913. [PMID: 31457077 PMCID: PMC6703862 DOI: 10.1126/sciadv.aav7913] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
Understanding of ancestral conditions for anthropoids has been hampered by the paucity of well-preserved early fossils. Here, we provide an unprecedented view of the cerebral morphology of the 20-million-year-old Chilecebus carrascoensis, the best-preserved early diverging platyrrhine known, obtained via high-resolution CT scanning and 3D digital reconstruction. These analyses are crucial for reconstructing ancestral brain conditions in platyrrhines and anthropoids given the early diverging position of Chilecebus. Although small, the brain of Chilecebus is not lissencephalic and presents at least seven pairs of sulci on its endocast. Comparisons of Chilecebus and other basal anthropoids indicate that the major brain subdivisions of these early anthropoids exhibit no consistent scaling pattern relative to the overall brain size. Many gross cerebral features appear to have transformed in a mosaic fashion and probably have originated in platyrrhine and catarrhine anthropoids independently, involving multiple, independent instances of size increase, as well as some secondary decreases.
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Affiliation(s)
- Xijun Ni
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi Zhi Men Wai Street, Beijing 100044, China
- Division of Paleontology and Richard Gilder Graduate School, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
- CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - John J. Flynn
- Division of Paleontology and Richard Gilder Graduate School, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA
| | - André R. Wyss
- Department of Earth Science, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Chi Zhang
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, 142 Xi Zhi Men Wai Street, Beijing 100044, China
- CAS Center for Excellence in Life and Paleoenvironment, Beijing 100044, China
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20
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van der Geer AAE. Effect of isolation on coat colour polymorphism of Polynesian rats in Island Southeast Asia and the Pacific. PeerJ 2019; 7:e6894. [PMID: 31119086 PMCID: PMC6511229 DOI: 10.7717/peerj.6894] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 04/02/2019] [Indexed: 01/03/2023] Open
Abstract
Populations of vertebrate species introduced onto islands regularly develop similar phenotypic changes, e.g., larger or smaller body size, shortened limbs, duller coats, as well as behavioural changes such as increased tameness and reduced flight-initiation distance. These changes overlap in part with those associated with the 'domestication syndrome', especially tameness and changes in coat patterns, and might indicate a similar neural crest involvement in the concurrent development of multiple phenotypic traits. Here I examine long-term data on free-living populations of wild Polynesian rats from seven mainland countries and 117 islands (n = 3,034), covering the species' native and introduced range. Mainland populations showed no aberrant coat patterns, with the exception of one albino, whereas aberrant coat patterns were found in 12 island populations. Observed coat colour polymorphisms consisted of leucistic (including singular white patches), melanistic (darkly pigmented) and piebald (mixed) coat patterns. After isolation for at least seven centuries, wild Polynesian rat populations on islands seem to exhibit a trend towards a higher incidence of aberrant coat patterns. These phenotypic changes are here explained as a neutral, non-adaptive process, likely part of the 'domestication syndrome' (via the commensal pathway of domestication), in combination with genetic drift, little or no gene flow between the islands and/or the mainland and a relaxed selection (as a result of the weakening or removal of competitor/predator pressure) under commensality.
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21
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Lyras GA. Brain Changes during Phyletic Dwarfing in Elephants and Hippos. BRAIN, BEHAVIOR AND EVOLUTION 2019; 92:167-181. [PMID: 30943507 DOI: 10.1159/000497268] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 01/27/2019] [Indexed: 11/19/2022]
Abstract
Of all known insular mammals, hippos and elephants present the extremes of body size decrease, reducing to 4 and a mere 2% of their ancestral mainland size, respectively. Despite the numerous studies on these taxa, what happens to their relative brain size during phyletic dwarfing is not well known, and results are sometimes conflicting. For example, relative brain size increase has been noted in the Sicilian dwarf elephant, Palaeoloxodon falconeri, whereas relative brain size decrease has been postulated for Malagasy dwarf hippos. Here, I perform an analysis of brain, skull, and body size of 3 insular elephants (Palaeoloxodon "mnaidriensis," P. tiliensis, and P. falconeri) and 3 insular hippos (Hippopotamus madagascariensis, H. lemerlei, and H. minor) to address this issue and to test whether relative brain size in phyletic dwarf species can be predicted. The results presented here show that the encephalization of all insular elephants and hippos is higher than that of their continental relatives. P. falconeri in particular has an enormous encephalization increase, which has so far not been reported in any other insular mammal. Insular brain size cannot be reliably predicted using either static allometric or ontogenetic scaling models. The results of this study indicate that insular dwarf species follow brain-body allometric relationships different from the expected patterns seen for their mainland relatives.
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Affiliation(s)
- George A Lyras
- Department of Geology and Geoenvironment, National and Kapodistrian University of Athens, Athens, Greece,
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22
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Monson TA, Coleman JL, Hlusko LJ. Craniodental Allometry, Prenatal Growth Rates, and the Evolutionary Loss of the Third Molars in New World Monkeys. Anat Rec (Hoboken) 2018; 302:1419-1433. [PMID: 30315641 DOI: 10.1002/ar.23979] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/06/2018] [Accepted: 06/14/2018] [Indexed: 11/12/2022]
Abstract
A growing body of literature demonstrates that genetic patterning mechanisms underlie the relative proportions of the mammalian postcanine dentition with the third molar being key to understanding variation within the molar row. With this relatively recent insight, there has been renewed interest in mammalian taxa that have lost the third molars. Within platyrrhines, the marmosets and tamarins (Callitrichidae family) are characterized by small body size, claw-like nails, twinning, and reduced molar number. Small body size is hypothesized to have resulted in the third molar being crowded out of the jaws leading to its evolutionary loss in this family. To further explore this hypothesis, we measured the cranium and dentition of 142 individuals spanning all five platyrrhine families. These data reveal that callitrichids have a significantly smaller proportion of mandibular postcanine tooth row length relative to other platyrrhines, refuting the "crowding out" hypothesis. However, postcanine tooth row length is significantly correlated with mandibular length and cranial length (P < 0.01) across all platyrrhines providing evidence for a strong allometric association between postcanine tooth row length and body size more generally. The small body size that characterizes callitrichids results in part from slower prenatal growth rates. Given the allometric relationship between postcanine tooth row length and body size, reported here and in previous studies, we hypothesize that the evolutionary loss of the third molars in callitrichids results from the inhibition of third molar development as a consequence of the slower prenatal growth rates associated with small body size in this family. Anat Rec, 302:1419-1433, 2019. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Tesla A Monson
- Department of Integrative Biology, University of California, Berkeley, California.,Museum of Vertebrate Zoology, University of California, Berkeley, California.,Human Evolution Research Center, University of California, Berkeley, California
| | - Jeffrey L Coleman
- Department of Integrative Biology, University of California, Berkeley, California
| | - Leslea J Hlusko
- Department of Integrative Biology, University of California, Berkeley, California.,Museum of Vertebrate Zoology, University of California, Berkeley, California.,Human Evolution Research Center, University of California, Berkeley, California
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23
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Dome-headed, small-brained island mammal from the Late Cretaceous of Romania. Proc Natl Acad Sci U S A 2018; 115:4857-4862. [PMID: 29686084 DOI: 10.1073/pnas.1801143115] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The island effect is a well-known evolutionary phenomenon, in which island-dwelling species isolated in a resource-limited environment often modify their size, anatomy, and behaviors compared with mainland relatives. This has been well documented in modern and Cenozoic mammals, but it remains unclear whether older, more primitive Mesozoic mammals responded in similar ways to island habitats. We describe a reasonably complete and well-preserved skeleton of a kogaionid, an enigmatic radiation of Cretaceous island-dwelling multituberculate mammals previously represented by fragmentary fossils. This skeleton, from the latest Cretaceous of Romania, belongs to a previously unreported genus and species that possesses several aberrant features, including an autapomorphically domed skull and one of the smallest brains relative to body size of any advanced mammaliaform, which nonetheless retains enlarged olfactory bulbs and paraflocculi for sensory processing. Drawing on parallels with more recent island mammals, we interpret these unusual neurosensory features as related to the island effect. This indicates that the ability to adapt to insular environments developed early in mammalian history, before the advent of therian mammals, and mammals with insular-related modifications were key components of well-known dwarfed dinosaur faunas. Furthermore, the specimen suggests that brain size reduction, in association with heightened sensory acuity but without marked body size change, is a novel expression of the island effect in mammals.
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24
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25
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EarlyHomoand the role of the genus in paleoanthropology. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 165 Suppl 65:72-89. [DOI: 10.1002/ajpa.23387] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 12/12/2017] [Indexed: 11/07/2022]
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26
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Luo Y, Zhong MJ, Huang Y, Li F, Liao WB, Kotrschal A. Seasonality and brain size are negatively associated in frogs: evidence for the expensive brain framework. Sci Rep 2017; 7:16629. [PMID: 29192284 PMCID: PMC5709389 DOI: 10.1038/s41598-017-16921-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 11/20/2017] [Indexed: 12/22/2022] Open
Abstract
The challenges of seasonal environments are thought to contribute to brain evolution, but in which way is debated. According to the Cognitive Buffer Hypothesis (CBH) brain size should increase with seasonality, as the cognitive benefits of a larger brain should help overcoming periods of food scarcity via, for instance, increased behavioral flexibility. However, in line with the Expensive Brain Framework (EBF) brain size should decrease with seasonality because a smaller brain confers energetic benefits in periods of food scarcity. Empirical evidence is inconclusive and mostly limited to homoeothermic animals. Here we used phylogenetic comparative analyses to test the impact of seasonality on brain evolution across 30 species of anurans (frogs) experiencing a wide range of temperature and precipitation. Our results support the EBF because relative brain size and the size of the optic tectum were negatively correlated with variability in temperature. In contrast, we found no association between the variability in precipitation and the length of the dry season with either brain size or the sizes of other major brain regions. We suggest that seasonality-induced food scarcity resulting from higher variability in temperature constrains brain size evolution in anurans. Less seasonal environments may therefore facilitate the evolution of larger brains in poikilothermic animals.
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Affiliation(s)
- Yi Luo
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, 637009, Sichuan, China
- Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong, 637009, Sichuan, China
| | - Mao Jun Zhong
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, 637009, Sichuan, China
- Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong, 637009, Sichuan, China
| | - Yan Huang
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, 637009, Sichuan, China
- Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong, 637009, Sichuan, China
| | - Feng Li
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, 637009, Sichuan, China
- Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong, 637009, Sichuan, China
| | - Wen Bo Liao
- Key Laboratory of Southwest China Wildlife Resources Conservation (Ministry of Education), China West Normal University, Nanchong, 637009, Sichuan, China.
- Institute of Eco-adaptation in Amphibians and Reptiles, China West Normal University, Nanchong, 637009, Sichuan, China.
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27
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Diniz-Filho JAF, Raia P. Island Rule, quantitative genetics and brain-body size evolution in Homo floresiensis. Proc Biol Sci 2017; 284:20171065. [PMID: 28637851 PMCID: PMC5489739 DOI: 10.1098/rspb.2017.1065] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 05/23/2017] [Indexed: 12/23/2022] Open
Abstract
Colonization of islands often activate a complex chain of adaptive events that, over a relatively short evolutionary time, may drive strong shifts in body size, a pattern known as the Island Rule. It is arguably difficult to perform a direct analysis of the natural selection forces behind such a change in body size. Here, we used quantitative evolutionary genetic models, coupled with simulations and pattern-oriented modelling, to analyse the evolution of brain and body size in Homo floresiensis, a diminutive hominin species that appeared around 700 kya and survived up to relatively recent times (60-90 kya) on Flores Island, Indonesia. The hypothesis of neutral evolution was rejected in 97% of the simulations, and estimated selection gradients are within the range found in living natural populations. We showed that insularity may have triggered slightly different evolutionary trajectories for body and brain size, which means explaining the exceedingly small cranial volume of H. floresiensis requires additional selective forces acting on brain size alone. Our analyses also support previous conclusions that H. floresiensis may be most likely derived from an early Indonesian H. erectus, which is coherent with currently accepted biogeographical scenario for Homo expansion out of Africa.
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Affiliation(s)
- José Alexandre Felizola Diniz-Filho
- Departamento de Ecologia e PPG em Ecologia and Evolução, Universidade Federal de Goiás, Instituto de Ciências Biológicas, Goiania, GO, Brazil
| | - Pasquale Raia
- Dipartimento di Scienze della Terra, dell'Ambiente e delle Risorse, Università di Napoli Federico II, Napoli, Italy
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28
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Abstract
In investigating convergent minds, we need to be sure that the things we are looking at are both minds and convergent. In determining whether a shared character state represents a convergence between two organisms, we must know the wider distribution and primitive state of that character so that we can map that character and its state transitions onto a phylogenetic tree. When we do this, some apparently primitive shared traits may prove to represent convergent losses of cognitive capacities. To avoid having to talk about the minds of plants and paramecia, we need to go beyond assessments of behaviourally defined cognition to ask questions about mind in the primary sense of the word, defined by the presence of mental events and consciousness. These phenomena depend upon the possession of brains of adequate size and centralized ontogeny and organization. They are probably limited to vertebrates. Recent discoveries suggest that consciousness is adaptively valuable as a late error-detection mechanism in the initiation of action, and point to experimental techniques for assessing its presence or absence in non-human mammals.
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Affiliation(s)
- Matt Cartmill
- Department of Anthropology, Boston University, 22 Bay State Road, Boston, MA 02215, USA
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29
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Veitschegger K. The effect of body size evolution and ecology on encephalization in cave bears and extant relatives. BMC Evol Biol 2017; 17:124. [PMID: 28583080 PMCID: PMC5460516 DOI: 10.1186/s12862-017-0976-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 05/22/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The evolution of larger brain volumes relative to body size in Mammalia is the subject of an extensive amount of research. Early on palaeontologists were interested in the brain of cave bears, Ursus spelaeus, and described its morphology and size. However, until now, it was not possible to compare the absolute or relative brain size in a phylogenetic context due to the lack of an established phylogeny, comparative material, and phylogenetic comparative methods. In recent years, many tools for comparing traits within phylogenies were developed and the phylogenetic position of cave bears was resolved based on nuclear as well as mtDNA. RESULTS Cave bears exhibit significantly lower encephalization compared to their contemporary relatives and intraspecific brain mass variation remained rather small. Encephalization was correlated with the combined dormancy-diet score. Body size evolution was a main driver in the degree of encephalization in cave bears as it increased in a much higher pace than brain size. In Ursus spelaeus, brain and body size increase over time albeit differently paced. This rate pattern is different in the highest encephalized bear species within the dataset, Ursus malayanus. The brain size in this species increased while body size heavily decreased compared to its ancestral stage. CONCLUSIONS Early on in the evolution of cave bears encephalization decreased making it one of the least encephalized bear species compared to extant and extinct members of Ursidae. The results give reason to suspect that as herbivorous animals, cave bears might have exhibited a physiological buffer strategy to survive the strong seasonality of their environment. Thus, brain size was probably affected by the negative trade-off with adipose tissue as well as diet. The decrease of relative brain size in the herbivorous Ursus spelaeus is the result of a considerable increase in body size possibly in combination with environmental conditions forcing them to rest during winters.
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Affiliation(s)
- Kristof Veitschegger
- Palaeontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006, Zürich, Switzerland.
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Stanton DWG, Mulville JA, Bruford MW. Colonization of the Scottish islands via long-distance Neolithic transport of red deer (Cervus elaphus). Proc Biol Sci 2016; 283:rspb.2016.0095. [PMID: 27053752 PMCID: PMC4843653 DOI: 10.1098/rspb.2016.0095] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 03/07/2016] [Indexed: 02/01/2023] Open
Abstract
Red deer (Cervus elaphus) have played a key role in human societies throughout history, with important cultural significance and as a source of food and materials. This relationship can be traced back to the earliest human cultures and continues to the present day. Humans are thought to be responsible for the movement of a considerable number of deer throughout history, although the majority of these movements are poorly described or understood. Studying such translocations allows us to better understand ancient human-wildlife interactions, and in the case of island colonizations, informs us about ancient human maritime practices. This study uses DNA sequences to characterise red deer genetic diversity across the Scottish islands (Inner and Outer Hebrides and Orkney) and mainland using ancient deer samples, and attempts to infer historical colonization events. We show that deer from the Outer Hebrides and Orkney are unlikely to have originated from mainland Scotland, implying that humans introduced red deer from a greater distance. Our results are also inconsistent with an origin from Ireland or Norway, suggesting long-distance maritime travel by Neolithic people to the outer Scottish Isles from an unknown source. Common haplotypes and low genetic differentiation between the Outer Hebrides and Orkney imply common ancestry and/or gene flow across these islands. Close genetic proximity between the Inner Hebrides and Ireland, however, corroborates previous studies identifying mainland Britain as a source for red deer introductions into Ireland. This study provides important information on the processes that led to the current distribution of the largest surviving indigenous land mammal in the British Isles.
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Affiliation(s)
- David W G Stanton
- School of Biosciences, Cardiff University, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, UK
| | - Jacqueline A Mulville
- School of History, Archaeology and Religion, Cardiff University, Humanities Building, Column Drive, Cardiff CF10 3EU, UK
| | - Michael W Bruford
- School of Biosciences, Cardiff University, The Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, UK
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Affiliation(s)
- Aida Gómez-Robles
- Center for the Advanced Study of Human Paleobiology, Department of Anthropology, The George Washington University, Washington DC 20052, USA
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Sánchez-Villagra MR, Geiger M, Schneider RA. The taming of the neural crest: a developmental perspective on the origins of morphological covariation in domesticated mammals. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160107. [PMID: 27429770 PMCID: PMC4929905 DOI: 10.1098/rsos.160107] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/03/2016] [Indexed: 05/02/2023]
Abstract
Studies on domestication are blooming, but the developmental bases for the generation of domestication traits and breed diversity remain largely unexplored. Some phenotypic patterns of human neurocristopathies are suggestive of those reported for domesticated mammals and disrupting neural crest developmental programmes have been argued to be the source of traits deemed the 'domestication syndrome'. These character changes span multiple organ systems and morphological structures. But an in-depth examination within the phylogenetic framework of mammals including domesticated forms reveals that the distribution of such traits is not universal, with canids being the only group showing a large set of predicted features. Modularity of traits tied to phylogeny characterizes domesticated mammals: through selective breeding, individual behavioural and morphological traits can be reordered, truncated, augmented or deleted. Similarly, mammalian evolution on islands has resulted in suites of phenotypic changes like those of some domesticated forms. Many domesticated mammals can serve as valuable models for conducting comparative studies on the evolutionary developmental biology of the neural crest, given that series of their embryos are readily available and that their phylogenetic histories and genomes are well characterized.
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Affiliation(s)
| | - Madeleine Geiger
- Palaeontological Institute and Museum, University of Zurich, Karl-Schmid-Street 4, 8006 Zurich, Switzerland
| | - Richard A. Schneider
- Department of Orthopaedic Surgery, University of Californiaat San Francisco, 513 Parnassus Avenue, S-1161, San Francisco, CA, USA
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Ballarin C, Povinelli M, Granato A, Panin M, Corain L, Peruffo A, Cozzi B. The Brain of the Domestic Bos taurus: Weight, Encephalization and Cerebellar Quotients, and Comparison with Other Domestic and Wild Cetartiodactyla. PLoS One 2016; 11:e0154580. [PMID: 27128674 PMCID: PMC4851379 DOI: 10.1371/journal.pone.0154580] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Accepted: 04/17/2016] [Indexed: 11/18/2022] Open
Abstract
The domestic bovine Bos taurus is raised worldwide for meat and milk production, or even for field work. However the functional anatomy of its central nervous system has received limited attention and most of the reported data in textbooks and reviews are derived from single specimens or relatively old literature. Here we report information on the brain of Bos taurus obtained by sampling 158 individuals, 150 of which at local abattoirs and 8 in the dissecting room, these latter subsequently formalin-fixed. Using body weight and fresh brain weight we calculated the Encephalization Quotient (EQ), and Cerebellar Quotient (CQ). Formalin-fixed brains sampled in the necropsy room were used to calculate the absolute and relative weight of the major components of the brain. The data that we obtained indicate that the domestic bovine Bos taurus possesses a large, convoluted brain, with a slightly lower weight than expected for an animal of its mass. Comparisons with other terrestrial and marine members of the order Cetartiodactyla suggested close similarity with other species with the same feeding adaptations, and with representative baleen whales. On the other hand differences with fish-hunting toothed whales suggest separate evolutionary pathways in brain evolution. Comparison with the other large domestic herbivore Equus caballus (belonging to the order Perissodactyla) indicates that Bos taurus underwent heavier selection of bodily traits, which is also possibly reflected in a comparatively lower EQ than in the horse. The data analyzed suggest that the brain of domestic bovine is potentially interesting for comparative neuroscience studies and may represents an alternative model to investigate neurodegeneration processes.
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Affiliation(s)
- Cristina Ballarin
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
| | - Michele Povinelli
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
| | - Alberto Granato
- Department of Psychology, Catholic University of Rome, Largo Gemelli 1, 20100 Milan (MI), Italy
| | - Mattia Panin
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
| | - Livio Corain
- Department of Management and Engineering, University of Padova, Stradella S. Nicola 3, 36100 Vicenza (VI), Italy
| | - Antonella Peruffo
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
| | - Bruno Cozzi
- Department of Comparative Biomedicine and Food Science, University of Padova, Viale dell’Università 16, 35020 Legnaro (PD), Italy
- * E-mail:
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Grabowski M. Bigger Brains Led to Bigger Bodies?: The Correlated Evolution of Human Brain and Body Size. CURRENT ANTHROPOLOGY 2016. [DOI: 10.1086/685655] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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35
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Currie A. Ethnographic analogy, the comparative method, and archaeological special pleading. STUDIES IN HISTORY AND PHILOSOPHY OF SCIENCE 2016; 55:84-94. [PMID: 26774072 DOI: 10.1016/j.shpsa.2015.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 08/05/2015] [Accepted: 08/05/2015] [Indexed: 06/05/2023]
Abstract
Ethnographic analogy, the use of comparative data from anthropology to inform reconstructions of past human societies, has a troubled history. Archaeologists often express concern about, or outright reject, the practice--and sometimes do so in problematically general terms. This is odd, as (or so I argue) the use of comparative data in archaeology is the same pattern of reasoning as the 'comparative method' in biology, which is a well-developed and robust set of inferences which play a central role in discovering the biological past. In pointing out this continuity, I argue that there is no 'special pleading' on the part of archaeologists in this regard: biologists must overcome analogous epistemic difficulties in their use of comparative data. I then go on to emphasize the local, empirically tractable ways in which particular ethnographic analogies may be licensed.
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Affiliation(s)
- Adrian Currie
- Philosophy Department, University of Calgary, 2500 University Dr NW, Calgary T2N1N4, Alberta, Canada.
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36
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Curnoe D, Ji X, Liu W, Bao Z, Taçon PSC, Ren L. A Hominin Femur with Archaic Affinities from the Late Pleistocene of Southwest China. PLoS One 2015; 10:e0143332. [PMID: 26678851 PMCID: PMC4683062 DOI: 10.1371/journal.pone.0143332] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/03/2015] [Indexed: 12/03/2022] Open
Abstract
The number of Late Pleistocene hominin species and the timing of their extinction are issues receiving renewed attention following genomic evidence for interbreeding between the ancestors of some living humans and archaic taxa. Yet, major gaps in the fossil record and uncertainties surrounding the age of key fossils have meant that these questions remain poorly understood. Here we describe and compare a highly unusual femur from Late Pleistocene sediments at Maludong (Yunnan), Southwest China, recovered along with cranial remains that exhibit a mixture of anatomically modern human and archaic traits. Our studies show that the Maludong femur has affinities to archaic hominins, especially Lower Pleistocene femora. However, the scarcity of later Middle and Late Pleistocene archaic remains in East Asia makes an assessment of systematically relevant character states difficult, warranting caution in assigning the specimen to a species at this time. The Maludong fossil probably samples an archaic population that survived until around 14,000 years ago in the biogeographically complex region of Southwest China.
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Affiliation(s)
- Darren Curnoe
- Palaeontology, Geobiology and Earth Archives Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia
- * E-mail: (DC); (XJ)
| | - Xueping Ji
- Yunnan Institute of Cultural Relics and Archaeology, Kunming, Yunnan, China
- * E-mail: (DC); (XJ)
| | - Wu Liu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Zhende Bao
- Mengzi Institute of Cultural Relics, Mengzi, Yunnan, China
| | - Paul S. C. Taçon
- Place, Evolution and Rock Art Heritage Unit, School of Humanities, Gold Coast Campus, Griffith University, Queensland, Australia
| | - Liang Ren
- Mengzi Institute of Cultural Relics, Mengzi, Yunnan, China
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37
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Larick R, Ciochon RL. Retracted: Early hominin biogeography in Island Southeast Asia. Evol Anthropol 2015; 24:185-213. [DOI: 10.1002/evan.21460] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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38
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Weisbecker V, Blomberg S, Goldizen AW, Brown M, Fisher D. The evolution of relative brain size in marsupials is energetically constrained but not driven by behavioral complexity. BRAIN, BEHAVIOR AND EVOLUTION 2015; 85:125-35. [PMID: 25966967 DOI: 10.1159/000377666] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/02/2015] [Indexed: 11/19/2022]
Abstract
Evolutionary increases in mammalian brain size relative to body size are energetically costly but are also thought to confer selective advantages by permitting the evolution of cognitively complex behaviors. However, many suggested associations between brain size and specific behaviors - particularly related to social complexity - are possibly confounded by the reproductive diversity of placental mammals, whose brain size evolution is the most frequently studied. Based on a phylogenetic generalized least squares analysis of a data set on the reproductively homogenous clade of marsupials, we provide the first quantitative comparison of two hypotheses based on energetic constraints (maternal investment and seasonality) with two hypotheses that posit behavioral selection on relative brain size (social complexity and environmental interactions). We show that the two behavioral hypotheses have far less support than the constraint hypotheses. The only unambiguous associates of brain size are the constraint variables of litter size and seasonality. We also found no association between brain size and specific behavioral complexity categories within kangaroos, dasyurids, and possums. The largest-brained marsupials after phylogenetic correction are from low-seasonality New Guinea, supporting the notion that low seasonality represents greater nutrition safety for brain maintenance. Alternatively, low seasonality might improve the maternal support of offspring brain growth. The lack of behavioral brain size associates, found here and elsewhere, supports the general 'cognitive buffer hypothesis' as the best explanatory framework of mammalian brain size evolution. However, it is possible that brain size alone simply does not provide sufficient resolution on the question of how brain morphology and cognitive capacities coevolve.
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Affiliation(s)
- Vera Weisbecker
- School of Biological Sciences, University of Queensland, St. Lucia, Qld., Australia
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39
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A Brief Overview of the Last 10 Years of Major Late Pleistocene Discoveries in the Old World: Homo floresiensis, Neanderthal, and Denisovan. ACTA ACUST UNITED AC 2014. [DOI: 10.1155/2014/581689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In the last ten years, new fossil, archaeological, and genetic data have significantly altered our understanding of the peopling of the Old World in the Late Pleistocene. Scholars have long been challenged to define humanity’s place in evolution and to trace our phylogeny. Differences in the skeletal morphology of hominin fossils have often led to the naming of distinct new species, but recent genetic findings have challenged the traditional perspective by demonstrating that modern human DNA contains genes inherited from Neanderthals and Denisovans, thus questioning their status as separate species. The recent discovery of Homo floresiensis from Flores Island has also raised interesting queries about how much genetic and morphological diversity was present during the Late Pleistocene. This paper discusses the nature and implications of the evidence with respect to Homo floresiensis, Neanderthals, and Denisovans and briefly reviews major Late Pleistocene discoveries from the last ten years of research in the Old World and their significance to the study of human evolution.
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40
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VAN DER GEER AAE. Parallel patterns and trends in functional structures in extinct island mammals. Integr Zool 2014; 9:167-182. [DOI: 10.1111/1749-4877.12066] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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41
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Montgomery SH. Primate brains, the ‘island rule’ and the evolution of Homo floresiensis. J Hum Evol 2013; 65:750-60. [DOI: 10.1016/j.jhevol.2013.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 08/21/2013] [Accepted: 08/26/2013] [Indexed: 10/26/2022]
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42
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Montgomery SH, Geisler JH, McGowen MR, Fox C, Marino L, Gatesy J. The evolutionary history of cetacean brain and body size. Evolution 2013; 67:3339-53. [PMID: 24152011 DOI: 10.1111/evo.12197] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 06/13/2013] [Indexed: 11/30/2022]
Abstract
Cetaceans rival primates in brain size relative to body size and include species with the largest brains and biggest bodies to have ever evolved. Cetaceans are remarkably diverse, varying in both phenotypes by several orders of magnitude, with notable differences between the two extant suborders, Mysticeti and Odontoceti. We analyzed the evolutionary history of brain and body mass, and relative brain size measured by the encephalization quotient (EQ), using a data set of extinct and extant taxa to capture temporal variation in the mode and direction of evolution. Our results suggest that cetacean brain and body mass evolved under strong directional trends to increase through time, but decreases in EQ were widespread. Mysticetes have significantly lower EQs than odontocetes due to a shift in brain:body allometry following the divergence of the suborders, caused by rapid increases in body mass in Mysticeti and a period of body mass reduction in Odontoceti. The pattern in Cetacea contrasts with that in primates, which experienced strong trends to increase brain mass and relative brain size, but not body mass. We discuss what these analyses reveal about the convergent evolution of large brains, and highlight that until recently the most encephalized mammals were odontocetes, not primates.
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Affiliation(s)
- Stephen H Montgomery
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, United Kingdom.
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43
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Baab KL, McNulty KP, Harvati K. Homo floresiensis contextualized: a geometric morphometric comparative analysis of fossil and pathological human samples. PLoS One 2013; 8:e69119. [PMID: 23874886 PMCID: PMC3707875 DOI: 10.1371/journal.pone.0069119] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 06/11/2013] [Indexed: 11/19/2022] Open
Abstract
The origin of hominins found on the remote Indonesian island of Flores remains highly contentious. These specimens may represent a new hominin species, Homo floresiensis, descended from a local population of Homo erectus or from an earlier (pre-H. erectus) migration of a small-bodied and small-brained hominin out of Africa. Alternatively, some workers suggest that some or all of the specimens recovered from Liang Bua are pathological members of a small-bodied modern human population. Pathological conditions proposed to explain their documented anatomical features include microcephaly, myxoedematous endemic hypothyroidism (“cretinism”) and Laron syndrome (primary growth hormone insensitivity). This study evaluates evolutionary and pathological hypotheses through comparative analysis of cranial morphology. Geometric morphometric analyses of landmark data show that the sole Flores cranium (LB1) is clearly distinct from healthy modern humans and from those exhibiting hypothyroidism and Laron syndrome. Modern human microcephalic specimens converge, to some extent, on crania of extinct species of Homo. However in the features that distinguish these two groups, LB1 consistently groups with fossil hominins and is most similar to H. erectus. Our study provides further support for recognizing the Flores hominins as a distinct species, H. floresiensis, whose affinities lie with archaic Homo.
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Affiliation(s)
- Karen L. Baab
- Department of Anthropology and Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
| | - Kieran P. McNulty
- Evolutionary Anthropology Laboratory and Department of Anthropology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Katerina Harvati
- Department of Early Prehistory and Quaternary Ecology, Senckenberg Center for Human Evolution and Paleoecology, Eberhard Karls University of Tübingen, Tübingen, Germany
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Kubo D, Kono RT, Kaifu Y. Brain size of Homo floresiensis and its evolutionary implications. Proc Biol Sci 2013; 280:20130338. [PMID: 23595271 DOI: 10.1098/rspb.2013.0338] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The extremely small endocranial volume (ECV) of LB1, the type specimen of Homo floresiensis, poses a challenge in our understanding of human brain evolution. Some researchers hypothesize dramatic dwarfing of relative brain size from Homo erectus presumably without significant decrease in intellectual function, whereas others expect a lesser degree of brain diminution from a more primitive, small-brained form of hominin currently undocumented in eastern Asia. However, inconsistency in the published ECVs for LB1 (380-430 cc), unclear human intraspecific brain-body size scaling and other uncertainties have hampered elaborative modelling of its brain size reduction. In this study, we accurately determine the ECV of LB1 using high-resolution micro-CT scan. The ECV of LB1 thus measured, 426 cc, is larger than the commonly cited figure in previous studies (400 cc). Coupled with brain-body size correlation in Homo sapiens calculated based on a sample from 20 worldwide modern human populations, we construct new models of the brain size reduction in the evolution of H. floresiensis. The results show a more significant contribution of scaling effect than previously claimed.
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Affiliation(s)
- Daisuke Kubo
- Department of Biological Sciences, The University of Tokyo, , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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45
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Neill D. Life's timekeeper. Ageing Res Rev 2013; 12:567-78. [PMID: 23354279 DOI: 10.1016/j.arr.2013.01.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 01/08/2013] [Accepted: 01/10/2013] [Indexed: 12/18/2022]
Abstract
Life's timekeeper is a 'free-running' intracellular oscillator synchronised across all cells. It runs throughout life splitting lifespan into equal length phases. During the maturational period it controls the overall rate of progression whereas in the post-maturational period it controls the overall rate of ageing. This includes the rate of senescence and hence time to death. As such life's timekeeper equates maturational and post-maturational time, hence explains the tight correlation between these time periods that has existed throughout mammalian evolution. Life's timekeeper is proposed to have played an important role in vertebrate evolution. A slower oscillatory frequency results in proportional life phase prolongation. This leads to increased body and brain size, together with extended lifespan. Higher brain centres, neocortex in mammals, are disproportionately enlarged. Hence behavioural capacity is increased. The extended post-maturational period ensures that there is enough time in order that the behavioural advantages can be fully manifest in the environment. A faster oscillatory frequency would result in proportional life phase reduction. This process however would lead to reduced behavioural capacity, and is hence unlikely to be positively selected. Therefore throughout evolution life's timekeeper has operated to extend lifespan. It has hence functioned to promote longevity as opposed to ageing.
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Affiliation(s)
- David Neill
- Department of Psychiatry, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom.
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46
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Montgomery SH, Mundy NI. Parallel episodes of phyletic dwarfism in callitrichid and cheirogaleid primates. J Evol Biol 2013; 26:810-9. [PMID: 23442013 DOI: 10.1111/jeb.12097] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 11/28/2012] [Indexed: 11/28/2022]
Abstract
The Callitrichidae are the smallest anthropoids, whereas the Cheirogaleidae include the smallest of all primates. Using species-level analyses, we show that these are derived conditions; both neonatal and adult body mass decreased in a gradual, phyletic manner in parallel across callitrichids, and across cheirogaleids. We identify lineages with particularly rapid decreases and highlight the pygmy marmoset, Callithrix pygmaea, as a phenotypic outlier. The life-history traits associated with body-mass reduction in each clade suggest that the convergent evolution of small body size was achieved by changes in different ontogenetic stages. Body-size reduction in callitrichids appears to be almost exclusively due to alterations in prenatal growth rate, whereas body-size reduction in cheirogaleids may have been largely due to reduced duration of growth phases. Finally, we use these results to discuss some of the debates surrounding the evolution of Homo floresiensis and suggest potential parallels between the evolution of H. floresiensis and callitrichids.
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Affiliation(s)
- S H Montgomery
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK.
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47
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Brusatte SL, Vremir M, Csiki-Sava Z, Turner AH, Watanabe A, Erickson GM, Norell MA. The Osteology of Balaur bondoc, an Island-Dwelling Dromaeosaurid (Dinosauria: Theropoda) from the Late Cretaceous of Romania. BULLETIN OF THE AMERICAN MUSEUM OF NATURAL HISTORY 2013. [DOI: 10.1206/798.1] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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48
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Hager R, Lu L, Rosen GD, Williams RW. Genetic architecture supports mosaic brain evolution and independent brain-body size regulation. Nat Commun 2013; 3:1079. [PMID: 23011133 PMCID: PMC4267555 DOI: 10.1038/ncomms2086] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 08/23/2012] [Indexed: 01/13/2023] Open
Abstract
The mammalian brain consists of distinct parts that fulfil different functions. Finlay and Darlington have argued that evolution of the mammalian brain is constrained by developmental programs, suggesting that different brain parts are not free to respond individually to selection and evolve independent of other parts or overall brain size. However, comparisons among mammals with matched brain weights often reveal greater differences in brain part size, arguing against strong developmental constraints. Here, we test these hypotheses using a quantitative genetic approach involving over 10,000 mice. We identify independent loci for size variation in seven key parts of the brain, and observe that brain parts show low or no phenotypic correlation, as is predicted by a mosaic scenario. We also demonstrate that variation in brain size is independently regulated from body size. The allometric relations seen at higher phylogenetic levels are thus unlikely to be the product of strong developmental constraints.
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Affiliation(s)
- Reinmar Hager
- Computational and Evolutionary Biology Group, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Lu Lu
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA.,Jiangsu Key Laboratory of Neuroregeneration, Nantong University, China
| | - Glenn D Rosen
- Department of Neurology, Beth Isreal Deaconess Medical Center, 330 Brookline Ave., Boston, MA 02215, USA
| | - Robert W Williams
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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Swanson EM, Holekamp KE, Lundrigan BL, Arsznov BM, Sakai ST. Multiple determinants of whole and regional brain volume among terrestrial carnivorans. PLoS One 2012; 7:e38447. [PMID: 22719890 PMCID: PMC3374790 DOI: 10.1371/journal.pone.0038447] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 05/07/2012] [Indexed: 11/18/2022] Open
Abstract
Mammalian brain volumes vary considerably, even after controlling for body size. Although several hypotheses have been proposed to explain this variation, most research in mammals on the evolution of encephalization has focused on primates, leaving the generality of these explanations uncertain. Furthermore, much research still addresses only one hypothesis at a time, despite the demonstrated importance of considering multiple factors simultaneously. We used phylogenetic comparative methods to investigate simultaneously the importance of several factors previously hypothesized to be important in neural evolution among mammalian carnivores, including social complexity, forelimb use, home range size, diet, life history, phylogeny, and recent evolutionary changes in body size. We also tested hypotheses suggesting roles for these variables in determining the relative volume of four brain regions measured using computed tomography. Our data suggest that, in contrast to brain size in primates, carnivoran brain size may lag behind body size over evolutionary time. Moreover, carnivore species that primarily consume vertebrates have the largest brains. Although we found no support for a role of social complexity in overall encephalization, relative cerebrum volume correlated positively with sociality. Finally, our results support negative relationships among different brain regions after accounting for overall endocranial volume, suggesting that increased size of one brain regions is often accompanied by reduced size in other regions rather than overall brain expansion.
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Affiliation(s)
- Eli M Swanson
- Department of Zoology, Michigan State University, East Lansing, Michigan, United States of America.
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Affiliation(s)
- P David Polly
- Department of Geological Sciences, Indiana University, Bloomington, IN 47405, USA.
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