title: Larval development of the oriental lancelet, Branchiostoma belcheri, in laboratory mass culture.
abstract: We are successfully maintaining a laboratory colony of the lancelet Branchiostoma belcheri bred in the laboratory. Based on living individuals in this mass culture, morphological characteristics from the seven-day larval to benthic juvenile stages have been studied. Most striking was that later larval development of B. belcheri showed great individual variation even in a rather stable culture environment. Metamorphosis first occurred on 60 days post fertilization (dpf) and was continuously observed throughout the present study up to 100 dpf. Morphological traits such as the number of primary gill slits and body size at the start of metamorphosis are apparently affected by culture condition. Body size measured in the largest individuals showed nearly linear growth at 0.087 mm/day. The variability found in larval development calls for caution when developmental stages and chronological ages are compared between populations. However, the developmental flexibility of this animal also raises the possibility that growth and sexual maturation could be controlled artificially in captivity.
authors.affiliation: Marine Biological Laboratory, Graduate School of Science, Hiroshima University, 2445 Mukaishima, Onomichi, Hiroshima 722-0073, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Urata
authors.forename: Nobuo
authors.initials: N
authors.lastname: Yamaguchi
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Henmi
authors.forename: Kinya
authors.initials: K
authors.lastname: Yasui
mesh_terms: D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D002816:Chordata, Nonvertebrate / Q000196:embryology / Q000502:physiology*; D005260:Female; D007814:Larva / Q000254:growth & development*; D008297:Male; D008675:Metamorphosis, Biological / Q000502:physiology*; D012098:Reproduction / Q000502:physiology*; D013997:Time Factors