High Blood Flow Into the Femur Indicates Elevated Aerobic Capacity in Synapsids Since the Synapsida-Sauropsida Split
Varanids are the only non-avian sauropsids that are known to approach the warm-blooded mammals in stamina. Furthermore, a much higher maximum metabolic rate (MMR) gives endotherms (including birds) higher stamina than crocodiles, turtles, and non-varanid lepidosaurs. This has led researchers to hypo...
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Frontiers Media S.A.
2021-12-01
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| Series: | Frontiers in Ecology and Evolution |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fevo.2021.751238/full |
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| author | Philipp L. Knaus Philipp L. Knaus Philipp L. Knaus Anneke H. van Heteren Anneke H. van Heteren Anneke H. van Heteren Jacqueline K. Lungmus Jacqueline K. Lungmus P. Martin Sander |
| author_facet | Philipp L. Knaus Philipp L. Knaus Philipp L. Knaus Anneke H. van Heteren Anneke H. van Heteren Anneke H. van Heteren Jacqueline K. Lungmus Jacqueline K. Lungmus P. Martin Sander |
| author_sort | Philipp L. Knaus |
| collection | DOAJ |
| description | Varanids are the only non-avian sauropsids that are known to approach the warm-blooded mammals in stamina. Furthermore, a much higher maximum metabolic rate (MMR) gives endotherms (including birds) higher stamina than crocodiles, turtles, and non-varanid lepidosaurs. This has led researchers to hypothesize that mammalian endothermy evolved as a second step after the acquisition of elevated MMR in non-mammalian therapsids from a plesiomorphic state of low metabolic rates. In recent amniotes, MMR correlates with the index of blood flow into the femur (Qi), which is calculated from femoral length and the cross-sectional area of the nutrient foramen. Thus, Qi may serve as an indicator of MMR range in extinct animals. Using the Qi proxy and phylogenetic eigenvector maps, here we show that elevated MMRs evolved near the base of Synapsida. Non-mammalian synapsids, including caseids, edaphosaurids, sphenacodontids, dicynodonts, gorgonopsids, and non-mammalian cynodonts, show Qi values in the range of recent endotherms and varanids, suggesting that raised MMRs either evolved in synapsids shortly after the Synapsida-Sauropsida split in the Mississippian or that the low MMR of lepidosaurs and turtles is apomorphic, as has been postulated for crocodiles. |
| first_indexed | 2024-12-22T00:45:33Z |
| format | Article |
| id | doaj.art-175562ef85af413f9496f257ff905ed2 |
| institution | Directory Open Access Journal |
| issn | 2296-701X |
| language | English |
| last_indexed | 2024-12-22T00:45:33Z |
| publishDate | 2021-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Ecology and Evolution |
| spelling | doaj.art-175562ef85af413f9496f257ff905ed22022-12-21T18:44:34ZengFrontiers Media S.A.Frontiers in Ecology and Evolution2296-701X2021-12-01910.3389/fevo.2021.751238751238High Blood Flow Into the Femur Indicates Elevated Aerobic Capacity in Synapsids Since the Synapsida-Sauropsida SplitPhilipp L. Knaus0Philipp L. Knaus1Philipp L. Knaus2Anneke H. van Heteren3Anneke H. van Heteren4Anneke H. van Heteren5Jacqueline K. Lungmus6Jacqueline K. Lungmus7P. Martin Sander8Institut für Biologie, Humboldt-Universität zu Berlin, Berlin, GermanyInstitut für Geowissenschaften, Universität Bonn, Bonn, GermanyMuseum für Naturkunde Berlin, Leibniz-Institut für Evolutions – und Biodiversitätsforschung, Berlin, GermanySektion Mammalogie, Zoologische Staatssammlung München – Staatliche Naturwissenschaftliche Sammlungen Bayerns, Munich, GermanyGeobio-Center, Ludwig-Maximilians-Universität München, Munich, GermanyDepartment Biologie II, Ludwig-Maximilians-Universität München, Munich, GermanyDepartment of Organismal Biology and Anatomy, University of Chicago, Chicago, IL, United StatesNegaunee Integrative Research Center, Field Museum of Natural History, Chicago, IL, United StatesInstitut für Geowissenschaften, Universität Bonn, Bonn, GermanyVaranids are the only non-avian sauropsids that are known to approach the warm-blooded mammals in stamina. Furthermore, a much higher maximum metabolic rate (MMR) gives endotherms (including birds) higher stamina than crocodiles, turtles, and non-varanid lepidosaurs. This has led researchers to hypothesize that mammalian endothermy evolved as a second step after the acquisition of elevated MMR in non-mammalian therapsids from a plesiomorphic state of low metabolic rates. In recent amniotes, MMR correlates with the index of blood flow into the femur (Qi), which is calculated from femoral length and the cross-sectional area of the nutrient foramen. Thus, Qi may serve as an indicator of MMR range in extinct animals. Using the Qi proxy and phylogenetic eigenvector maps, here we show that elevated MMRs evolved near the base of Synapsida. Non-mammalian synapsids, including caseids, edaphosaurids, sphenacodontids, dicynodonts, gorgonopsids, and non-mammalian cynodonts, show Qi values in the range of recent endotherms and varanids, suggesting that raised MMRs either evolved in synapsids shortly after the Synapsida-Sauropsida split in the Mississippian or that the low MMR of lepidosaurs and turtles is apomorphic, as has been postulated for crocodiles.https://www.frontiersin.org/articles/10.3389/fevo.2021.751238/fullMMReigenvectorpelycosaurtherapsidmicroanatomybone |
| spellingShingle | Philipp L. Knaus Philipp L. Knaus Philipp L. Knaus Anneke H. van Heteren Anneke H. van Heteren Anneke H. van Heteren Jacqueline K. Lungmus Jacqueline K. Lungmus P. Martin Sander High Blood Flow Into the Femur Indicates Elevated Aerobic Capacity in Synapsids Since the Synapsida-Sauropsida Split Frontiers in Ecology and Evolution MMR eigenvector pelycosaur therapsid microanatomy bone |
| title | High Blood Flow Into the Femur Indicates Elevated Aerobic Capacity in Synapsids Since the Synapsida-Sauropsida Split |
| title_full | High Blood Flow Into the Femur Indicates Elevated Aerobic Capacity in Synapsids Since the Synapsida-Sauropsida Split |
| title_fullStr | High Blood Flow Into the Femur Indicates Elevated Aerobic Capacity in Synapsids Since the Synapsida-Sauropsida Split |
| title_full_unstemmed | High Blood Flow Into the Femur Indicates Elevated Aerobic Capacity in Synapsids Since the Synapsida-Sauropsida Split |
| title_short | High Blood Flow Into the Femur Indicates Elevated Aerobic Capacity in Synapsids Since the Synapsida-Sauropsida Split |
| title_sort | high blood flow into the femur indicates elevated aerobic capacity in synapsids since the synapsida sauropsida split |
| topic | MMR eigenvector pelycosaur therapsid microanatomy bone |
| url | https://www.frontiersin.org/articles/10.3389/fevo.2021.751238/full |
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