title: Allometric growth in the extant coelacanth lung during ontogenetic development.
abstract: Coelacanths are lobe-finned fishes known from the Devonian to Recent that were long considered extinct, until the discovery of two living species in deep marine waters of the Mozambique Channel and Sulawesi. Despite extensive studies, the pulmonary system of extant coelacanths has not been fully investigated. Here we confirm the presence of a lung and discuss its allometric growth in Latimeria chalumnae, based on a unique ontogenetic series. Our results demonstrate the presence of a potentially functional, well-developed lung in the earliest known coelacanth embryo, and its arrested growth at later ontogenetic stages, when the lung is clearly vestigial. The parallel development of a fatty organ for buoyancy control suggests a unique adaptation to deep-water environments. Furthermore, we provide the first evidence for the presence of small, hard, flexible plates around the lung in L. chalumnae, and consider them homologous to the plates of the 'calcified lung' of fossil coelacanths.
authors.affiliation: Departamento de Zoologia, Universidade do Estado do Rio de Janeiro, R. São Francisco Xavier, 524-Maracanã, Rio de Janeiro 20550-900, Brazil.
authors.forename: Camila
authors.initials: C
authors.lastname: Cupello
authors.affiliation: Departamento de Zoologia, Universidade do Estado do Rio de Janeiro, R. São Francisco Xavier, 524-Maracanã, Rio de Janeiro 20550-900, Brazil.
authors.forename: Paulo M
authors.initials: PM
authors.lastname: Brito
authors.affiliation: Département Écologie et Gestion de la Biodiversité, UMR 7179 CNRS-MNHN, Mécanismes adaptatifs des organismes aux communautés, Muséum national d'Histoire naturelle, 57 rue Cuvier, Paris 75231, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Herbin
authors.affiliation: Département des Milieux et Peuplements Aquatiques, UMR 7208 (CNRS-IRD-MNHN-UPMC), Equipe BOREA, Muséum national d'Histoire naturelle, CP026, 43 rue Cuvier, Paris 75231, France.
authors.forename: François J
authors.initials: FJ
authors.lastname: Meunier
authors.affiliation: Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P, UMR 7207), Sorbonne Universités, MNHN, CNRS, UPMC-Paris6, Muséum national d'histoire naturelle, 57 rue Cuvier, CP38, Paris F-75005, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Janvier
authors.affiliation: Laboratory for Evolutionary Morphology, RIKEN, 2-2-3 Minatojima-minami, Chuo-ku, Kobe 650-0047, Japan.
authors.forename: Hugo
authors.initials: H
authors.lastname: Dutel
authors.affiliation: Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P, UMR 7207), Sorbonne Universités, MNHN, CNRS, UPMC-Paris6, Muséum national d'histoire naturelle, 57 rue Cuvier, CP38, Paris F-75005, France.
authors.forename: Gaël
authors.initials: G
authors.lastname: Clément
mesh_terms: D000818:Animals; D002113:Calcification, Physiologic; D004625:Embryo, Nonmammalian / Q000196:embryology; D005399:Fishes / Q000196:embryology* / Q000254:growth & development; D005580:Fossils; D007214:Indonesia; D008168:Lung / Q000000981:diagnostic imaging / Q000196:embryology* / Q000254:growth & development; D009073:Mozambique; D010802:Phylogeny; D014057:Tomography, X-Ray Computed