The impact of regional climate on the evolution of mammals: a case study using fossil horses.
Abstract: One of the classic examples of faunal turnover in the fossil record is the Miocene transition from faunas dominated by anchitheriine horses with low-crowned molar teeth to faunas with hipparionine horses characterized by high-crowned teeth. The spread of hipparionine horses is associated with increased seasonality and the expansion of open habitats. It is generally accepted that anchitheriine horses did not display an evolutionary increase in tooth crown height prior to their extinction. Nevertheless, to test whether anchitheriines showed any changes interpretable as adaptation to local conditions, we analyzed molar teeth from multiple populations of Anchitherium in three dimensions. Our results show differences in tooth morphology that suggest incipient hypsodonty in Spain, the first region experiencing increasingly arid conditions in the early Miocene of Europe. Furthermore, analyses of tooth wear show that Spanish specimens cluster with present ungulates that eat foliage together with grasses and shrubs, whereas German specimens cluster with present-day ungulates that eat mostly foliage. Taken together, even a taxon such as Anchitherium, with a long and successful history of forest adaptation, did respond to regional environmental changes in an adaptive manner.
Publication Date: 2009-09-07 PubMed ID: 19735525DOI: 10.1111/j.1558-5646.2009.00830.xGoogle Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The research article discusses how regional climatic changes influenced the evolution of horse species, based on an analysis of their molar teeth fossils. The authors argue that even species extremely adapted to certain environments, like the forest-dwelling Anchitherium horse, show signs of adaptation to changing regional conditions, like increasing aridity.
Objective and Methodology
- The study revolved around the Miocene era’s faunal turnover, where fossil records show a shift from the domination of Anchitheriine horses with low-crowned teeth to Hipparionine horses characterized by high-crowned teeth.
- This transition is associated with an increase in seasonality and the growth of open habitats.
- Through an analysis of molar teeth from several populations of Anchitherium, the authors aim to test whether the Anchitheriine horses exhibited any evolutionary changes as adaptation to these environmental changes.
Findings
- The results of this 3D dental analysis indicated changes in tooth morphology suggesting the onset of hypsodonty (elongation of teeth crowns) in Spain, the first region known to encounter increasingly arid conditions during the early Miocene.
- Additional analysis of tooth wear revealed interesting dietary patterns associated with regional environments. Spanish specimens were found to be similar to today’s ungulates (hoofed animals) that feed on a mix of foliage, grasses, and shrubs, reflecting adaptations to a drier, open habitat.
- By contrast, German specimens were discovered to cluster with present-day ungulates predominantly feeding on foliage, indicating a forest-dwelling lifestyle resembling the Anchitherium’s original adaptations.
Conclusions
- The conclusion drawn from these findings is that even species, like Anchitherium horses, historically adapted to forest living, displayed adaptive responses to regional environmental shifts.
- These insights highlight the vital impact that regional climates have in driving evolution, even among highly specialized species.
Cite This Article
APA
Eronen JT, Evans AR, Fortelius M, Jernvall J.
(2009).
The impact of regional climate on the evolution of mammals: a case study using fossil horses.
Evolution, 64(2), 398-408.
https://doi.org/10.1111/j.1558-5646.2009.00830.x Publication
Researcher Affiliations
- Department of Geology, University of Helsinki, P.O. Box 64, FIN-00014, Finland. Jussi.T.Eronen@helsinki.fi
MeSH Terms
- Animals
- Biological Evolution
- Climate
- Fossils
- Horses / genetics
- Tooth
Citations
This article has been cited 5 times.- Cirilli O, Machado H, Arroyo-Cabrales J, Barrón-Ortiz CI, Davis E, Jass CN, Jukar AM, Landry Z, Marín-Leyva AH, Pandolfi L, Pushkina D, Rook L, Saarinen J, Scott E, Semprebon G, Strani F, Villavicencio NA, Kaya F, Bernor RL. Evolution of the Family Equidae, Subfamily Equinae, in North, Central and South America, Eurasia and Africa during the Plio-Pleistocene.. Biology (Basel) 2022 Aug 24;11(9).
- Pelletier M, Kotiaho A, Niinimäki S, Salmi AK. Identifying early stages of reindeer domestication in the archaeological record: a 3D morphological investigation on forelimb bones of modern populations from Fennoscandia.. Archaeol Anthropol Sci 2020;12(8):169.
- Tütken T, Kaiser TM, Vennemann T, Merceron G. Opportunistic feeding strategy for the earliest old world hypsodont equids: evidence from stable isotope and dental wear proxies.. PLoS One 2013;8(9):e74463.
- Cantalapiedra JL, Hernández Fernández M, Morales J. Biomic specialization and speciation rates in ruminants (Cetartiodactyla, Mammalia): a test of the resource-use hypothesis at the global scale.. PLoS One 2011;6(12):e28749.
- Raia P, Carotenuto F, Eronen JT, Fortelius M. Longer in the tooth, shorter in the record? The evolutionary correlates of hypsodonty in Neogene ruminants.. Proc Biol Sci 2011 Dec 7;278(1724):3474-81.
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