The outer epithelium of free-swimming larvae of marine invertebrates iscomposed of several cell types and performs a variety of vital functions. In bryozoan larvae,early anatomical studies revealed a rather complex organization of this epithelium. Thepresent contribution re-examines the available morphological descriptions, as well asinvestigates anatomically and ultrastructurally the epispheral (aboral) part of the outerpallial epithelium in contrasting larval types of six marine bryozoans from three orders —Cheilostomatida, Ctenostomatida, and Cyclostomatida. A total of 11 cell types wereidentified — three of them are typical for most of the studied larvae, the rest are unique tospecific larval types. Based on the data obtained, we conducted a comparative analysis andassigned potential functions to particular types of cells during larval life. We proposed thehypothesis that immersion/invagination of the larval pallial epithelium (which was accom-panied by cell enlargement in ciliary locomotory corona) occurred independently indifferent bryozoan lineages and was associated with acquisition of incubation. We alsoconsider the presence of the cuticle above the episphere and the absence of cilia in mostprincipal pallial epithelial cells as plesiomorphic traits of bryozoan larvae.
Original languageEnglish
Pages (from-to)369-403
JournalInvertebrate Zoology
Volume19
Issue number4
StatePublished - 2022

    Research areas

  • larval epithelium, ultrastructure, Embryonic incubation, marine inverte-brates, evolution

    Scopus subject areas

  • Animal Science and Zoology

ID: 100966205