Wing bone laminarity is not an adaptation for torsional resistance in bats
Torsional loading is a common feature of skeletal biomechanics during vertebrate flight. The importance of resisting torsional loads is best illustrated by the convergence of wing bone structure (e.g., long with thin walls) across extant bats and birds. Whether or not such a convergence occurs at th...
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| Format: | Article |
| Language: | English |
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PeerJ Inc.
2015-03-01
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| Series: | PeerJ |
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| Online Access: | https://peerj.com/articles/823.pdf |
| _version_ | 1797418900259864576 |
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| author | Andrew H. Lee Erin L.R. Simons |
| author_facet | Andrew H. Lee Erin L.R. Simons |
| author_sort | Andrew H. Lee |
| collection | DOAJ |
| description | Torsional loading is a common feature of skeletal biomechanics during vertebrate flight. The importance of resisting torsional loads is best illustrated by the convergence of wing bone structure (e.g., long with thin walls) across extant bats and birds. Whether or not such a convergence occurs at the microstructural level is less clear. In volant birds, the humeri and ulnae often contain abundant laminar bony tissue in which primary circumferential vascular canals course concentrically about the long axis of the bone. These circumferential canals and the matrix surrounding them presumably function to resist the tissue-level shear stress caused by flight-induced torsion. Here, we assess whether or not laminar bone is a general adaptive feature in extant flying vertebrates using a histological analysis of bat bones. We sampled the humeri from six adult taxa representing a broad phylogenetic and body size range (6–1,000 g). Transverse thick sections were prepared from the midshaft of each humerus. Bone tissue was classified based on the predominant orientation of primary vascular canals. Our results show that humeri from bats across a wide phylogenetic and body size range do not contain any laminar bone. Instead, humeri are essentially avascular in bats below about 100 g and are poorly vascularized with occasional longitudinal to slightly radial canals in large bats. In contrast, humeri from birds across a comparable size range (40–1,000 g) are highly vascularized with a wide range in bone laminarity. Phylogenetically-informed scaling analyses reveal that the difference in vascularity between birds and bats is best explained by higher somatic relative growth rates in birds. The presence of wing bone laminarity in birds and its absence in bats suggests that laminar bone is not a necessary biomechanical feature in flying vertebrates and may be apomorphic to birds. |
| first_indexed | 2024-03-09T06:39:40Z |
| format | Article |
| id | doaj.art-dab112c2eff240c59352f7ceb322ef06 |
| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T06:39:40Z |
| publishDate | 2015-03-01 |
| publisher | PeerJ Inc. |
| record_format | Article |
| series | PeerJ |
| spelling | doaj.art-dab112c2eff240c59352f7ceb322ef062023-12-03T10:53:56ZengPeerJ Inc.PeerJ2167-83592015-03-013e82310.7717/peerj.823823Wing bone laminarity is not an adaptation for torsional resistance in batsAndrew H. Lee0Erin L.R. Simons1Department of Anatomy, Midwestern University, Glendale, AZ, USADepartment of Anatomy, Midwestern University, Glendale, AZ, USATorsional loading is a common feature of skeletal biomechanics during vertebrate flight. The importance of resisting torsional loads is best illustrated by the convergence of wing bone structure (e.g., long with thin walls) across extant bats and birds. Whether or not such a convergence occurs at the microstructural level is less clear. In volant birds, the humeri and ulnae often contain abundant laminar bony tissue in which primary circumferential vascular canals course concentrically about the long axis of the bone. These circumferential canals and the matrix surrounding them presumably function to resist the tissue-level shear stress caused by flight-induced torsion. Here, we assess whether or not laminar bone is a general adaptive feature in extant flying vertebrates using a histological analysis of bat bones. We sampled the humeri from six adult taxa representing a broad phylogenetic and body size range (6–1,000 g). Transverse thick sections were prepared from the midshaft of each humerus. Bone tissue was classified based on the predominant orientation of primary vascular canals. Our results show that humeri from bats across a wide phylogenetic and body size range do not contain any laminar bone. Instead, humeri are essentially avascular in bats below about 100 g and are poorly vascularized with occasional longitudinal to slightly radial canals in large bats. In contrast, humeri from birds across a comparable size range (40–1,000 g) are highly vascularized with a wide range in bone laminarity. Phylogenetically-informed scaling analyses reveal that the difference in vascularity between birds and bats is best explained by higher somatic relative growth rates in birds. The presence of wing bone laminarity in birds and its absence in bats suggests that laminar bone is not a necessary biomechanical feature in flying vertebrates and may be apomorphic to birds.https://peerj.com/articles/823.pdfFlightBone histologyAvascular boneGrowth rateBatBird |
| spellingShingle | Andrew H. Lee Erin L.R. Simons Wing bone laminarity is not an adaptation for torsional resistance in bats PeerJ Flight Bone histology Avascular bone Growth rate Bat Bird |
| title | Wing bone laminarity is not an adaptation for torsional resistance in bats |
| title_full | Wing bone laminarity is not an adaptation for torsional resistance in bats |
| title_fullStr | Wing bone laminarity is not an adaptation for torsional resistance in bats |
| title_full_unstemmed | Wing bone laminarity is not an adaptation for torsional resistance in bats |
| title_short | Wing bone laminarity is not an adaptation for torsional resistance in bats |
| title_sort | wing bone laminarity is not an adaptation for torsional resistance in bats |
| topic | Flight Bone histology Avascular bone Growth rate Bat Bird |
| url | https://peerj.com/articles/823.pdf |
| work_keys_str_mv | AT andrewhlee wingbonelaminarityisnotanadaptationfortorsionalresistanceinbats AT erinlrsimons wingbonelaminarityisnotanadaptationfortorsionalresistanceinbats |