{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T05:24:31Z","timestamp":1786944271190,"version":"build-2736575974"},"reference-count":33,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,8,16]],"date-time":"2026-08-16T00:00:00Z","timestamp":1786838400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"},{"start":{"date-parts":[[2026,8,16]],"date-time":"2026-08-16T00:00:00Z","timestamp":1786838400000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Journal of Anatomy"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    The morphology and internal structure of tetrapod limb bones reflect complex interactions between functional demands, mechanical loading, and environmental conditions. In most tetrapods, limb bone microanatomy shows a clear ecological signal, with aquatic taxa typically displaying increased bone compactness and terrestrial taxa exhibiting more open medullary cavities. Testudines represent a notable exception to this pattern, as both terrestrial and aquatic turtles possess unusually compact long bones, suggesting that factors beyond habitat alone shape their skeletal design. Here, we present the first comprehensive whole\u2010bone, longitudinal analysis of cortical bone mass, geometry, tissue quality, and mechanostat\u2010related distribution\/quality (d\/q) relationships in turtle long bones, aiming to evaluate how locomotor ecology modulates bone design within the constraints of the turtle bauplan. We analyzed femora and humeri of four turtle species spanning a terrestrial\u2013aquatic gradient (\n                    <jats:italic>Chelonoidis carbonarius<\/jats:italic>\n                    ,\n                    <jats:italic>Chelonoidis chilensis<\/jats:italic>\n                    ,\n                    <jats:italic>Trachemys dorbignii<\/jats:italic>\n                    , and\n                    <jats:italic>Phrynops hilarii<\/jats:italic>\n                    ) using peripheral quantitative computed tomography (pQCT). Ten serial cross\u2010sections along each bone were assessed to quantify cortical bone mineral content, cortical area, volumetric bone mineral density, cross\u2010sectional moments of inertia, bone strength indices, and d\/q relationships between tissue stiffness and cross\u2010sectional design. Statistical comparisons focused on mid\u2010diaphyseal regions, with interspecific differences evaluated using ANOVA, and mechanostat\u2010related patterns examined through correlation analyses and ANCOVA. All species exhibited the characteristic turtle \u201cover\u2010designed\u201d condition, with abundant cortical bone and peak mass and density at midshaft. However, marked interspecific differences emerged in bone geometry and in the organization of cortical tissue. The terrestrial species, particularly\n                    <jats:italic>Chelonoidis carbonarius<\/jats:italic>\n                    , showed higher cortical mass and larger moments of inertia, reflecting enhanced resistance to bending under weight\u2010bearing locomotion. In contrast, the more aquatic\n                    <jats:italic>Phrynops hilarii<\/jats:italic>\n                    displayed lower moments of inertia and flatter or near\u2010zero d\/q slopes, indicating a biomechanical strategy favoring compressive stiffness via endosteal infilling rather than structural optimization for bending. Intermediate species occupied transitional positions along this gradient. These results demonstrate that, despite strong phylogenetic constraints associated with the turtle bauplan, the spatial distribution of cortical bone is finely tuned to locomotor ecology. The bone mechanostat in turtles operates within an \u201cover\u2010designed\u201d framework to produce distinct structural solutions for terrestrial versus aquatic loading regimes. Our findings provide a quantitative link between habitat, locomotor mode, and long\u2010bone design, revealing that turtle limbs are not simply overbuilt, but precisely engineered for their mechanical environments.\n                  <\/jats:p>","DOI":"10.1111\/joa.70219","type":"journal-article","created":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T04:32:25Z","timestamp":1786941145000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["The over\u2010designed limb: Skeletal robustness and locomotor adaptation in terrestrial and freshwater turtles"],"prefix":"10.1111","author":[{"ORCID":"https:\/\/orcid.org\/0009-0004-2684-7098","authenticated-orcid":false,"given":"Juan Miguel","family":"Slongo Sobron","sequence":"first","affiliation":[{"name":"Laboratorio de Herpetolog\u00eda CICYTTP (CONICET\u2010UADER\u2010Pcia. De Entre R\u00edos)  Diamante Entre R\u00edos Argentina"},{"name":"CIBTA (UADER\u2010CONICET)  Oro Verde Entre R\u00edos Argentina"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gustavo Roberto","family":"Cointry","sequence":"additional","affiliation":[{"name":"Facultad de Ciencias M\u00e9dicas, Centro de Estudios de Metabolismo Fosfoc\u00e1lcico Universidad Nacional de Rosario\u2010 CONICET  Rosario Argentina"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ricardo Francisco","family":"Capozza","sequence":"additional","affiliation":[{"name":"Facultad de Ciencias M\u00e9dicas, Centro de Estudios de Metabolismo Fosfoc\u00e1lcico Universidad Nacional de Rosario\u2010 CONICET  Rosario Argentina"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Adriana Silvina","family":"Manzano","sequence":"additional","affiliation":[{"name":"Laboratorio de Herpetolog\u00eda CICYTTP (CONICET\u2010UADER\u2010Pcia. De Entre R\u00edos)  Diamante Entre R\u00edos Argentina"},{"name":"CIBTA (UADER\u2010CONICET)  Oro Verde Entre R\u00edos Argentina"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,8,16]]},"reference":[{"issue":"2","key":"e_1_2_9_2_1","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1111\/j.1469-7580.2008.00937.x","article-title":"The distal forelimb musculature in aquatic and terrestrial turtles: phylogeny or environmental constraints?","volume":"213","author":"Abdala V.","year":"2008","journal-title":"Journal of Anatomy"},{"issue":"6","key":"e_1_2_9_3_1","doi-asserted-by":"crossref","first-page":"1058","DOI":"10.1093\/icb\/icu032","article-title":"Diversity of limb\u2010bone safety factors for locomotion in terrestrial vertebrates: evolution and mixed chains","volume":"54","author":"Blob R.W.","year":"2014","journal-title":"Integrative and Comparative Biology"},{"issue":"8","key":"e_1_2_9_4_1","doi-asserted-by":"crossref","first-page":"1187","DOI":"10.1242\/jeb.012989","article-title":"Mechanics of limb bone loading during terrestrial locomotion in river cooter turtles (Pseudemys concinna)","volume":"211","author":"Butcher M.T.","year":"2008","journal-title":"Journal of Experimental Biology"},{"issue":"15","key":"e_1_2_9_5_1","doi-asserted-by":"crossref","first-page":"2397","DOI":"10.1242\/jeb.018986","article-title":"In vivo strains in the femur of river cooter turtles (Pseudemys concinna) during terrestrial locomotion: tests of force\u2010platform models of loading mechanics","volume":"211","author":"Butcher M.T.","year":"2008","journal-title":"Journal of Experimental Biology"},{"issue":"2","key":"e_1_2_9_6_1","doi-asserted-by":"crossref","first-page":"384","DOI":"10.1111\/j.1095-8312.2010.01431.x","article-title":"Evolution of humeral microanatomy and lifestyle in amniotes, and some comments on palaeobiological inferences","volume":"100","author":"Canoville A.","year":"2010","journal-title":"Biological Journal of the Linnean Society"},{"issue":"2","key":"e_1_2_9_7_1","first-page":"185","article-title":"Mineralization\u2010 and remodeling\u2010unrelated improvement of the post\u2010yield properties of rat cortical bone by high doses of olpadronate","volume":"13","author":"Capozza R.F.","year":"2013","journal-title":"Journal of Musculoskeletal and Neuronal Interactions"},{"key":"e_1_2_9_8_1","volume-title":"Skeletal function and form","author":"Carter D.R.","year":"2001"},{"issue":"4","key":"e_1_2_9_9_1","doi-asserted-by":"crossref","first-page":"327","DOI":"10.1016\/S0306-9877(96)90181-4","article-title":"Mechanical optimization of bone","volume":"46","author":"Chigira M.","year":"1996","journal-title":"Medical Hypotheses"},{"key":"e_1_2_9_10_1","first-page":"29","article-title":"The pQCT \u201cbone strength indices\u201d (BSIs, SSI). Relative mechanical impact and diagnostic value of the indicators of bone tissue and design quality employed in their calculation in healthy men and pre\u2010 and post\u2010menopausal women","volume":"14","author":"Cointry G.R.","year":"2014","journal-title":"Journal of Musculoskeletal & Neuronal Interactions"},{"issue":"18","key":"e_1_2_9_11_1","doi-asserted-by":"crossref","first-page":"2495","DOI":"10.1242\/jeb.202.18.2495","article-title":"What determines the bending strength of compact bone?","volume":"202","author":"Currey J.D.","year":"1999","journal-title":"Journal of Experimental Biology"},{"key":"e_1_2_9_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.crpv.2005.01.003"},{"key":"e_1_2_9_13_1","doi-asserted-by":"publisher","DOI":"10.1111\/evo.13747"},{"issue":"3","key":"e_1_2_9_14_1","first-page":"263","article-title":"Analysis of biomechanical effects on bone and on the muscle\u2010bone interactions in small animal models","volume":"1","author":"Ferretti J.L.","year":"2001","journal-title":"Journal of Musculoskeletal and Neuronal Interactions"},{"issue":"1","key":"e_1_2_9_15_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1002\/ar.1092190104","article-title":"Bone \u201cmass\u201d and the \u201cmechanostat\u201d: a proposal","volume":"219","author":"Frost H.M.","year":"1987","journal-title":"The Anatomical Record"},{"issue":"2","key":"e_1_2_9_16_1","doi-asserted-by":"crossref","first-page":"1081","DOI":"10.1002\/ar.a.10119","article-title":"Bone's mechanostat: a 2003 update","volume":"275","author":"Frost H.M.","year":"2003","journal-title":"The Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology"},{"issue":"4","key":"e_1_2_9_17_1","doi-asserted-by":"crossref","first-page":"335","DOI":"10.1111\/j.1463-6409.2005.00198.x","article-title":"Microanatomy of the radius and lifestyle in amniotes (vertebrata, Tetrapoda)","volume":"34","author":"Germain D.","year":"2005","journal-title":"Zoologica Scripta"},{"issue":"2","key":"e_1_2_9_18_1","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1111\/j.1469-7998.1999.tb00985.x","article-title":"Ontogenetic changes in mineralization and bone geometry in the femur of muskoxen (Ovibos moschatus)","volume":"247","author":"Heinrich R.E.","year":"1999","journal-title":"Journal of Zoology"},{"issue":"2","key":"e_1_2_9_19_1","doi-asserted-by":"crossref","first-page":"350","DOI":"10.1111\/bij.12660","article-title":"Biomechanical evolution of solid bones in large animals: a microanatomical investigation","volume":"117","author":"Houssaye A.","year":"2016","journal-title":"Biological Journal of the Linnean Society"},{"issue":"3","key":"e_1_2_9_20_1","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1111\/jzo.12714","article-title":"Allometric growth of limb and body proportions in crocodylians","volume":"309","author":"Iijima M.","year":"2019","journal-title":"Journal of Zoology"},{"issue":"5","key":"e_1_2_9_21_1","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1016\/j.crpv.2011.02.003","article-title":"Bone microanatomy and lifestyle: a descriptive approach","volume":"10","author":"Laurin M.","year":"2011","journal-title":"Comptes Rendus Palevol"},{"issue":"4","key":"e_1_2_9_22_1","doi-asserted-by":"crossref","first-page":"719","DOI":"10.1111\/bij.12336","article-title":"Turtle humeral microanatomy and its relationship to lifestyle","volume":"112","author":"Nakajima Y.","year":"2014","journal-title":"Biological Journal of the Linnean Society"},{"issue":"19","key":"e_1_2_9_23_1","doi-asserted-by":"crossref","first-page":"3261","DOI":"10.1242\/jeb.204.19.3261","article-title":"Comparative kinematics of the forelimb during swimming in red\u2010eared slider turtles (Trachemys scripta) and spiny softshell turtles (Apalone spinifera)","volume":"204","author":"Pace C.M.","year":"2001","journal-title":"Journal of Experimental Biology"},{"issue":"6","key":"e_1_2_9_24_1","doi-asserted-by":"crossref","first-page":"875","DOI":"10.1111\/joa.12975","article-title":"Osteohistological correlates of muscular attachment in terrestrial and freshwater testudines","volume":"234","author":"Pereyra M.E.","year":"2019","journal-title":"Journal of Anatomy"},{"issue":"4","key":"e_1_2_9_25_1","first-page":"436","article-title":"Adjusting for the partial volume effect in cortical bone analyses of pQCT images","volume":"4","author":"Rittweger J.","year":"2004","journal-title":"Journal of Musculoskeletal and Neuronal Interactions"},{"key":"e_1_2_9_26_1","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1006\/jhev.1999.0322","article-title":"Body size, body shape, and long bone strength in modern humans","volume":"38","author":"Ruff C.B.","year":"2000","journal-title":"Journal of Human Evolution"},{"key":"e_1_2_9_27_1","first-page":"232","article-title":"From mechanostat theory to development of the \u201cfunctional muscle\u2013bone unit\u201d","volume":"5","author":"Schoenau E.","year":"2005","journal-title":"Journal of Musculoskeletal and Neuronal Interactions"},{"issue":"3","key":"e_1_2_9_28_1","doi-asserted-by":"crossref","first-page":"335","DOI":"10.1163\/15685381-bja10223","article-title":"The ontogeny of the femur and tibia during post\u2010hatching development in the tortoise Chelonoidis chilensis (Testudinidae)","volume":"46","author":"Slongo Sobron J.M.","year":"2025","journal-title":"Amphibia\u2010Reptilia"},{"key":"e_1_2_9_29_1","first-page":"1","article-title":"Is the shape of turtle claws driven by locomotor modes?","volume":"49","author":"Tulli M.J.","year":"2022","journal-title":"Evolutionary Biology"},{"issue":"6","key":"e_1_2_9_30_1","doi-asserted-by":"crossref","first-page":"1112","DOI":"10.1111\/joa.13161","article-title":"Biomechanical properties of anuran long bones: correlations with locomotor modes and habitat use","volume":"236","author":"Vera M.C.","year":"2020","journal-title":"Journal of Anatomy"},{"issue":"3","key":"e_1_2_9_31_1","doi-asserted-by":"crossref","first-page":"702","DOI":"10.1111\/joa.13710","article-title":"Hind limb muscles influence the architectural properties of long bones in frogs","volume":"241","author":"Vera M.C.","year":"2022","journal-title":"Journal of Anatomy"},{"issue":"4","key":"e_1_2_9_32_1","doi-asserted-by":"crossref","first-page":"593","DOI":"10.1002\/jmor.20968","article-title":"Comparative limb bone scaling in turtles: phylogenetic transitions with changes in functional demands?","volume":"280","author":"Young V.K.H.","year":"2019","journal-title":"Journal of Morphology"},{"issue":"6","key":"e_1_2_9_33_1","doi-asserted-by":"crossref","DOI":"10.1098\/rsbl.2015.0110","article-title":"Limb bone loading in swimming turtles: changes in loading facilitate transitions from tubular to flipper\u2010shaped limbs during aquatic invasions","volume":"11","author":"Young V.K.H.","year":"2015","journal-title":"Biology Letters"},{"issue":"21","key":"e_1_2_9_34_1","first-page":"3873","article-title":"Humeral loads during swimming and walking in turtles: implications for morphological change during aquatic reinvasions","volume":"220","author":"Young V.K.H.","year":"2017","journal-title":"Journal of Experimental Biology"}],"container-title":["Journal of Anatomy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/joa.70219","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1111\/joa.70219","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/joa.70219","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,17]],"date-time":"2026-08-17T04:32:47Z","timestamp":1786941167000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1111\/joa.70219"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,16]]},"references-count":33,"alternative-id":["10.1111\/joa.70219"],"URL":"https:\/\/doi.org\/10.1111\/joa.70219","archive":["Portico"],"relation":{},"ISSN":["0021-8782","1469-7580"],"issn-type":[{"value":"0021-8782","type":"print"},{"value":"1469-7580","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,16]]},"assertion":[{"value":"2026-01-16","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-07-16","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2026-08-16","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"joa.70219"}}