title: Trunk exoskeleton in teleosts is mesodermal in origin.
abstract: The vertebrate mineralized skeleton is known to have first emerged as an exoskeleton that extensively covered the fossil jawless fish. The evolutionary origin of this exoskeleton has long been attributed to the emergence of the neural crest, but experimental evaluation for this is still poor. Here we determine the embryonic origin of scales and fin rays of medaka (teleost trunk exoskeletons) by applying long-term cell labelling methods, and demonstrate that both tissues are mesodermal in origin. Neural crest cells, however, fail to contribute to these tissues. This result suggests that the trunk neural crest has no skeletogenic capability in fish, instead highlighting the dominant role of the mesoderm in the evolution of the trunk skeleton. This further implies that the role of the neural crest in skeletogenesis has been predominant in the cephalic region from the early stage of vertebrate evolution.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Shimada
authors.forename: Toru
authors.initials: T
authors.lastname: Kawanishi
authors.forename: Takuya
authors.initials: T
authors.lastname: Kaneko
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yoshihara
authors.forename: Tohru
authors.initials: T
authors.lastname: Yano
authors.forename: Keiji
authors.initials: K
authors.lastname: Inohaya
authors.forename: Masato
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kamei
authors.forename: Koji
authors.initials: K
authors.lastname: Tamura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takeda
mesh_terms: D000818:Animals; D008648:Mesoderm / Q000033:anatomy & histology*; D009990:Oryzias / Q000033:anatomy & histology*; D012863:Skeleton
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