title: Novel morphological traits in the early developmental stages of Temnopleurus toreumaticus.
abstract: We have re-observed in detail the development of the sea urchin species Temnopleurus toreumaticus, which is considered to be a typical indirect-developing species with a feeding larval stage. In this re-observation, we discovered two new morphological traits in the early embryonic stages of T. toreumaticus. The first trait is that, immediately after fertilization, the egg enters a stage in which wrinkles form on its surface as a result of actin polymerization. The second new trait is that the blastulae form wrinkles; in sea urchins, this has previously been known only in direct-developing species that have a nonfeeding larval stage and form wrinkles during the blastula stage, before hatching. These phenomena indicate that after fertilization, the egg of T. toreumaticus undergoes a surface transformation that is unprecedented in echinoderms, and that an indirect-developing sea urchin can form a wrinkled blastula.
authors.affiliation: Biological Institute, Faculty of Education, Yamaguchi University, Yamaguchi 753-8513, Japan. chisak@yamaguchi-u.ac.jp
authors.forename: Chisato
authors.initials: C
authors.lastname: Kitazawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Nishimura
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Michihiro
authors.initials: M
authors.lastname: Nakano
authors.forename: Akira
authors.initials: A
authors.lastname: Yamanaka
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D036703:Blastula / Q000166:cytology*; D008853:Microscopy; D008856:Microscopy, Fluorescence; D012617:Sea Urchins / Q000166:cytology* / Q000254:growth & development*; D015053:Zygote / Q000166:cytology*
chemical_list: D000199:Actins