TY - JOUR

T1 - Aboral (pallial) epithelium in bryozoan larvae: a comparative morpho-functional analysis

AU - Kotenko, Olga N.

AU - Bagrov, Serge

AU - Ostrovsky, Andrew N.

PY - 2022

Y1 - 2022

N2 - 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.

AB - 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.

KW - larval epithelium

KW - ultrastructure

KW - Embryonic incubation

KW - marine inverte-brates

KW - evolution

UR - https://www.researchgate.net/publication/366124544_Aboral_pallial_epithelium_in_bryozoan_larvae_a_comparative_morpho-functional_analysis_Aboralnyj_pallialnyj_epitelij_licinok_msanok_sravnitelnyj_morfo-funkcionalnyj_analiz

M3 - Article

VL - 19

SP - 369

EP - 403

JO - Invertebrate Zoology

JF - Invertebrate Zoology

SN - 1812-9250

IS - 4

ER -