title: The pectoral fin muscles of the coelacanth Latimeria chalumnae: Functional and evolutionary implications for the fin-to-limb transition and subsequent evolution of tetrapods.
abstract: To investigate the morphology and evolutionary origin of muscles in vertebrate limbs, we conducted anatomical dissections, computed tomography and kinematic analyses on the pectoral fin of the African coelacanth, Latimeria chalumnae. We discovered nine antagonistic pairs of pronators and supinators that are anatomically and functionally distinct from the abductor and adductor superficiales and profundi. In particular, the first pronator and supinator pair represents mono- and biarticular muscles; a portion of the muscle fibers is attached to ridges on the humerus and is separated into two monoarticular muscles, whereas, as a biarticular muscle, the main body is inserted into the radius by crossing two joints from the shoulder girdle. This pair, consisting of a pronator and supinator, constitutes a muscle arrangement equivalent to two human antagonistic pairs of monoarticular muscles and one antagonistic pair of biarticular muscles in the stylopod between the shoulder and elbow joints. Our recent kinesiological and biomechanical engineering studies on human limbs have demonstrated that two antagonistic pairs of monoarticular muscles and one antagonistic pair of biarticular muscles in the stylopod (1) coordinately control output force and force direction at the wrist and ankle and (2) achieve a contact task to carry out weight-bearing motion and maintain stable posture. Therefore, along with dissections of the pectoral fins in two lungfish species, Neoceratodus forsteri and Protopterus aethiopicus, we discuss the functional and evolutionary implications for the fin-to-limb transition and subsequent evolution of tetrapods. Anat Rec, 299:1203-1223, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: The Graduate School of Science and Technology, Keio University, Tokyo, Japan.|Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Miyake
authors.affiliation: Kyoto University, Kyoto, Japan.
authors.forename: Minayori
authors.initials: M
authors.lastname: Kumamoto
authors.affiliation: Aquamarine Fukushima, Marine Science Museum, Iwaki, Japan.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Iwata
authors.affiliation: Institute of Biomechanical Control Systems, Kanazawa Institute of Technology, Hakusan, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Sato
authors.affiliation: Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Okabe
authors.affiliation: Department of Veterinary Medicine, Nihon University, Fujisawa, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Koie
authors.affiliation: Research Center of Computational Mechanics (RCCM), Inc, Tokyo, Japan.
authors.forename: Nori
authors.initials: N
authors.lastname: Kumai
authors.affiliation: Aquamarine Fukushima, Marine Science Museum, Iwaki, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Fujii
authors.affiliation: Aquamarine Fukushima, Marine Science Museum, Iwaki, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Matsuzaki
authors.affiliation: Aquamarine Fukushima, Marine Science Museum, Iwaki, Japan.
authors.forename: Chiho
authors.initials: C
authors.lastname: Nakamura
authors.affiliation: Aquamarine Fukushima, Marine Science Museum, Iwaki, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Yamauchi
authors.affiliation: Aquamarine Fukushima, Marine Science Museum, Iwaki, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Aquamarine Fukushima, Marine Science Museum, Iwaki, Japan.
authors.forename: Kohtaroh
authors.initials: K
authors.lastname: Yoshimura
authors.affiliation: Aquamarine Fukushima, Marine Science Museum, Iwaki, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Komoda
authors.affiliation: National Museum of Nature and Science, Tokyo, Japan.
authors.forename: Teruya
authors.initials: T
authors.lastname: Uyeno
authors.affiliation: Aquamarine Fukushima, Marine Science Museum, Iwaki, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Abe
mesh_terms: D058500:Animal Fins / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology; D000818:Animals; D005075:Biological Evolution; D001696:Biomechanical Phenomena / Q000502:physiology; D005399:Fishes / Q000033:anatomy & histology* / Q000502:physiology; D005580:Fossils; D010369:Pectoralis Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology; D010802:Phylogeny; D014057:Tomography, X-Ray Computed
keywords: Latimeria chalumnae; fin-to-limb transition; mono- and biarticular muscles; pectoral fin musculature; weight-bearing motion