{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T13:22:49Z","timestamp":1787664169195,"version":"build-2736575974"},"reference-count":78,"publisher":"Wiley","issue":"8","license":[{"start":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T00:00:00Z","timestamp":1785283200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T00:00:00Z","timestamp":1785283200000},"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 Morphology"],"published-print":{"date-parts":[[2026,8]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>\n                    Psittaciformes possess zygodactyl feet that support perching, climbing, inverted postures, and foot\u2010mediated food manipulation. Despite the functional importance of these behaviors, the myological and biomechanical bases of digital performance remain poorly documented in large\u2010bodied psittacids, particularly macaws. Here, we investigate the digitized musculature and estimate the functional force output of the foot in the red\u2010and\u2010green macaw. We describe the intrinsic and extrinsic muscles acting on the digits, quantify muscle length and mass, and estimate digit\u2010specific pinching forces based on physiological cross\u2010sectional area and mechanical advantage. Digit IV is the longest digit, and its primary flexor,\n                    <jats:italic>m. flexor perforatus digiti IV<\/jats:italic>\n                    , is the longest and most massive digital flexor. Consistent with this morphology, digit IV generated the greatest pinching force (8.63\u2009\u00b1\u20091.52\u2009N), indicating a dominant role in force production. The remaining digits are shorter and associated with more slender musculature, resulting in lower force outputs (digit II: 4.51\u2009\u00b1\u20090.92\u2009N; digit III: 2.29\u2009\u00b1\u20090.30\u2009N; digit I [hallux]: 1.06\u2009\u00b1\u20090.15\u2009N). The combined force of the posterior digits (I\u2009+\u2009IV; 9.69\u2009\u00b1\u20091.74\u2009N) approximates that of the anterior digits (II\u2009+\u2009III; 6.80\u2009\u00b1\u20091.22\u2009N), indicating a near\u2010balanced anterior\u2013posterior force distribution that likely enhances stability during perching and climbing while facilitating precise manipulative behaviors. Apparently, the total pedal force (16.49\u2009\u00b1\u20093.22\u2009N) scales with body size in Psittaciformes; however, this hypothesis requires testing by using explicit allometric and phylogenetic comparative approaches. Finally, this foot\u2010gripping force is lower than that reported for large raptors (Accipitriformes and Falconiformes), reflecting functional specialization of the macaw pes for controlled arboreal locomotion, inverted postures, and fine motor manipulation rather than maximal force generation.\n                  <\/jats:p>","DOI":"10.1002\/jmor.70152","type":"journal-article","created":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T06:05:53Z","timestamp":1785391553000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Functional Morphology of the Pedal Musculature and Grip Force Estimation in the Red\u2011and\u2011Green Macaw (\n                    <i>Ara chloropterus<\/i>\n                    Gray, 1859)"],"prefix":"10.1002","volume":"287","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7823-9068","authenticated-orcid":false,"given":"S\u00e9rgio Roberto","family":"Posso","sequence":"first","affiliation":[{"name":"LESCAN \u2013 Laboratory of Ecology, Systematics and Conservation of Neotropical Birds Mato Grosso do Sul Federal University Tr\u00eas Lagoas MS Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-8680-9825","authenticated-orcid":false,"given":"Vinicius Camargo","family":"Tavares","sequence":"additional","affiliation":[{"name":"LESCAN \u2013 Laboratory of Ecology, Systematics and Conservation of Neotropical Birds Mato Grosso do Sul Federal University Tr\u00eas Lagoas MS Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-2341-8268","authenticated-orcid":false,"given":"Ana Caroline M.","family":"Barbosa","sequence":"additional","affiliation":[{"name":"LESCAN \u2013 Laboratory of Ecology, Systematics and Conservation of Neotropical Birds Mato Grosso do Sul Federal University Tr\u00eas Lagoas MS Brazil"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,7,29]]},"reference":[{"key":"e_1_2_12_2_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7580.2010.01278.x"},{"key":"e_1_2_12_3_1","doi-asserted-by":"publisher","DOI":"10.1002\/ar.20909"},{"key":"e_1_2_12_4_1","doi-asserted-by":"publisher","DOI":"10.1111\/joa.12614"},{"key":"e_1_2_12_5_1","doi-asserted-by":"publisher","DOI":"10.1098\/rsos.140350"},{"key":"e_1_2_12_6_1","volume-title":"Handbook of Avian Anatomy: Nomina Anatomica Avium","author":"Baumel J. J.","year":"1993"},{"key":"e_1_2_12_7_1","doi-asserted-by":"publisher","DOI":"10.1093\/auk\/101.1.74"},{"key":"e_1_2_12_8_1","doi-asserted-by":"publisher","DOI":"10.2307\/4086020"},{"key":"e_1_2_12_9_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10164-007-0035-2"},{"key":"e_1_2_12_10_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmor.1051140102"},{"key":"e_1_2_12_11_1","first-page":"1","article-title":"The Scansorial Foot of the Woodpeckers, With Comments on the Evolution of Perching and Climbing Feet in Birds","volume":"1931","author":"Bock W. J.","year":"1959","journal-title":"American Museum Novitates"},{"issue":"1","key":"e_1_2_12_12_1","first-page":"222","article-title":"A Staining Method for Gross Dissection of Vertebrate Muscles","volume":"130","author":"Bock W. J.","year":"1972","journal-title":"Anatomischer Anzeiger"},{"key":"e_1_2_12_13_1","doi-asserted-by":"publisher","DOI":"10.1098\/rspb.2014.0765"},{"key":"e_1_2_12_14_1","doi-asserted-by":"publisher","DOI":"10.1093\/beheco\/arr114"},{"key":"e_1_2_12_15_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7998.1974.tb03156.x"},{"key":"e_1_2_12_16_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1474-919X.1978.tb06773.x"},{"key":"e_1_2_12_17_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.zool.2020.125877"},{"key":"e_1_2_12_18_1","doi-asserted-by":"publisher","DOI":"10.1111\/joa.12330"},{"key":"e_1_2_12_19_1","doi-asserted-by":"publisher","DOI":"10.1038\/s41467-024-54297-9"},{"key":"e_1_2_12_20_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmor.20253"},{"key":"e_1_2_12_21_1","doi-asserted-by":"publisher","DOI":"10.2307\/4511942"},{"key":"e_1_2_12_22_1","first-page":"280","volume-title":"Handbook of the Birds of the World","author":"Collar N. J.","year":"1997"},{"key":"e_1_2_12_23_1","doi-asserted-by":"publisher","DOI":"10.1111\/jzo.13014"},{"key":"e_1_2_12_24_1","first-page":"1","article-title":"A Morphological Study of the Cranial Muscles Associated With the Feeding Habit of Psittacula krameri Scopoli","volume":"3","author":"Dubale M. S.","year":"1965","journal-title":"Pavo"},{"key":"e_1_2_12_25_1","doi-asserted-by":"publisher","DOI":"10.1002\/ar.25667"},{"key":"e_1_2_12_26_1","volume-title":"The Origin and Evolution of Birds","author":"Feduccia A.","year":"1999"},{"key":"e_1_2_12_27_1","doi-asserted-by":"publisher","DOI":"10.2307\/2421553"},{"key":"e_1_2_12_28_1","volume-title":"Parrots of the World","author":"Forshaw J. M.","year":"1989"},{"key":"e_1_2_12_29_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0028964"},{"key":"e_1_2_12_30_1","volume-title":"Avian Myology","author":"George J. C.","year":"1966"},{"key":"e_1_2_12_31_1","first-page":"45","volume-title":"Araras da cidade \u2013 M\u00fasicas do Mato","author":"Guedes N. M. R.","year":"2012"},{"key":"e_1_2_12_32_1","doi-asserted-by":"publisher","DOI":"10.1126\/science.1157704"},{"key":"e_1_2_12_33_1","doi-asserted-by":"publisher","DOI":"10.1111\/joa.14144"},{"key":"e_1_2_12_34_1","volume-title":"Analysis of Vertebrate Structure","author":"Hildebrand M.","year":"2001"},{"key":"e_1_2_12_35_1","first-page":"427","article-title":"Zur Morphologie Der Kiefermuskulatur Der V\u00f6gel","volume":"70","author":"Hofer H.","year":"1950","journal-title":"Zoologische Jahrb\u00fccher. Abteilung f\u00fcr Anatomie und Ontogenie der Tiere"},{"key":"e_1_2_12_36_1","first-page":"225","article-title":"Die Kiefermuskulatur Der Papageien Des Evolutions Problem","volume":"72","author":"Hofer H.","year":"1953","journal-title":"Biologisches Zentralblatt"},{"key":"e_1_2_12_37_1","first-page":"207","article-title":"A Numerical Study of the Wing and Leg of Tinamous (Tinamidae)","volume":"46","author":"Hudson G. E.","year":"1972","journal-title":"Northwest Science"},{"key":"e_1_2_12_38_1","unstructured":"IUCN.2026. The IUCN Red List of Threatened Species (Version 2025\u20102).https:\/\/www.iucnredlist.org."},{"key":"e_1_2_12_39_1","doi-asserted-by":"publisher","DOI":"10.1126\/science.1253451"},{"key":"e_1_2_12_40_1","volume-title":"The Inner Bird: Anatomy and Evolution","author":"Kaiser G. W.","year":"2007"},{"key":"e_1_2_12_41_1","volume-title":"Vertebrates: Comparative Anatomy, Function, Evolution","author":"Kardong K. V.","year":"2011"},{"key":"e_1_2_12_42_1","doi-asserted-by":"publisher","DOI":"10.3390\/d11070109"},{"key":"e_1_2_12_43_1","volume-title":"Studien \u00fcber die trigeminus\u2010versorgte Kaumuskulatur der Sauropsiden","author":"Lakjer T.","year":"1926"},{"key":"e_1_2_12_44_1","doi-asserted-by":"publisher","DOI":"10.1111\/btp.12099"},{"key":"e_1_2_12_45_1","doi-asserted-by":"publisher","DOI":"10.1163\/156854201X00260"},{"key":"e_1_2_12_46_1","first-page":"584","article-title":"Untersuchungen \u00dcber Die Visceralmuskulatur Der Sauropsiden","volume":"72","author":"Lubosch W.","year":"1933","journal-title":"Gegenbaurs Morphologisches Jahrbuch"},{"key":"e_1_2_12_47_1","volume-title":"The Grasping Hand: Advances in Psychology","author":"Mackenzie C. L.","year":"1994"},{"key":"e_1_2_12_48_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7580.2008.00929.x"},{"key":"e_1_2_12_49_1","doi-asserted-by":"publisher","DOI":"10.1676\/07-038.1"},{"key":"e_1_2_12_50_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2409658122"},{"key":"e_1_2_12_51_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmor.1058"},{"key":"e_1_2_12_52_1","first-page":"305","article-title":"Biologisch\u2010Anatomische Studien Am Sch\u00e4del Von Ara Macao","volume":"70","author":"Moller W.","year":"1950","journal-title":"Morphologisches Jahrbuch"},{"key":"e_1_2_12_53_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmor.20172"},{"key":"e_1_2_12_54_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10531-015-1036-z"},{"key":"e_1_2_12_55_1","doi-asserted-by":"publisher","DOI":"10.1186\/s40657-019-0177-2"},{"key":"e_1_2_12_56_1","doi-asserted-by":"publisher","DOI":"10.1016\/0021-9290(95)00137-9"},{"key":"e_1_2_12_57_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1439-0264.2010.01017.x"},{"key":"e_1_2_12_58_1","volume-title":"Anatomia comparada do esqueleto da cabe\u00e7a e da musculatura da mastiga\u00e7\u00e3o de araras (Aves: Psittaciformes: Arinae) [Comparative anatomy of the skull and masticatory muscles of macaws (Aves: Psittaciformes: Arinae)] [Doctoral dissertation, Universidade Federal Rural do Rio de Janeiro]","author":"Porto M.","year":"2004"},{"key":"e_1_2_12_59_1","doi-asserted-by":"publisher","DOI":"10.1002\/ar.70188"},{"key":"e_1_2_12_60_1","doi-asserted-by":"publisher","DOI":"10.1590\/1519-6984.20113"},{"key":"e_1_2_12_61_1","volume-title":"Manual of Ornithology: Avian Structure & Function","author":"Proctor N. S.","year":"1993"},{"key":"e_1_2_12_62_1","doi-asserted-by":"publisher","DOI":"10.1038\/nature15697"},{"key":"e_1_2_12_63_1","doi-asserted-by":"publisher","DOI":"10.58843\/ornneo.vi.755"},{"key":"e_1_2_12_64_1","doi-asserted-by":"publisher","DOI":"10.1590\/1519-6984.280711"},{"key":"e_1_2_12_65_1","doi-asserted-by":"publisher","DOI":"10.7554\/eLife.46415"},{"key":"e_1_2_12_66_1","first-page":"37","article-title":"Registros E Documenta\u00e7\u00e3o Fotogr\u00e1fica Da Alimenta\u00e7\u00e3o Da Arara\u2010Vermelha\u2010Grande (Ara Chloropterus) Na Regi\u00e3o Noroeste Do Paran\u00e1 (Psittaciformes: Psittacidae)","volume":"159","author":"Scherer\u2010Neto P.","year":"2011","journal-title":"Atualidades Ornitol\u00f3gicas On\u2010line"},{"key":"e_1_2_12_67_1","doi-asserted-by":"publisher","DOI":"10.1038\/nmeth.2089"},{"key":"e_1_2_12_68_1","volume-title":"Ornitologia Brasileira","author":"Sick H.","year":"2001"},{"key":"e_1_2_12_69_1","doi-asserted-by":"publisher","DOI":"10.1038\/ncomms1448"},{"key":"e_1_2_12_70_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmor.10577"},{"key":"e_1_2_12_71_1","doi-asserted-by":"publisher","DOI":"10.1111\/brv.12010"},{"key":"e_1_2_12_72_1","doi-asserted-by":"publisher","DOI":"10.2108\/zsj.20.749"},{"key":"e_1_2_12_73_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmor.10172"},{"key":"e_1_2_12_74_1","doi-asserted-by":"publisher","DOI":"10.1002\/jmor.10408"},{"key":"e_1_2_12_75_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1558-5646.2012.01752.x"},{"key":"e_1_2_12_76_1","first-page":"189","volume-title":"Myologia. \u2014 Handbook of Avian Anatomy: Nomina Anatomica Avium","author":"Vanden Berge J. C.","year":"1993"},{"key":"e_1_2_12_77_1","first-page":"1","article-title":"The Hindlimb Musculature of the True Owls (Strigidae: Strigiformes): Morphological Peculiarities and General Adaptations","volume":"31","author":"Volkov S. V.","year":"2004","journal-title":"Ornitologia"},{"key":"e_1_2_12_78_1","doi-asserted-by":"publisher","DOI":"10.1093\/auk\/119.4.1052"},{"key":"e_1_2_12_79_1","first-page":"391","volume-title":"The Skull: Volume 2. Patterns of Structural and Systematic Diversity","author":"Zusi R. L.","year":"1993"}],"container-title":["Journal of Morphology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/jmor.70152","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1002\/jmor.70152","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/jmor.70152","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,25]],"date-time":"2026-08-25T12:59:59Z","timestamp":1787662799000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/jmor.70152"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,29]]},"references-count":78,"journal-issue":{"issue":"8","published-print":{"date-parts":[[2026,8]]}},"alternative-id":["10.1002\/jmor.70152"],"URL":"https:\/\/doi.org\/10.1002\/jmor.70152","archive":["Portico"],"relation":{},"ISSN":["0362-2525","1097-4687"],"issn-type":[{"value":"0362-2525","type":"print"},{"value":"1097-4687","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,29]]},"assertion":[{"value":"2026-04-16","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":"2026-07-29","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e70152"}}