Mnemiopsis leidyi

 

Among the Metazoa, the ctenophores are one of the earliest diverging lineages.  The lobate ctenophore, Mnemiopsis leidyi, is becoming an emerging model system for understanding ctenophore development.  An improved understanding of development in this lobate ctenophore is of fundamental importance to exploring and understanding the biological basis of novelties associated with the Ctenophora, as well as identifying important developmental events associated with the early evolution of metazoans.

Embryonic and Larval Development of Mnemiopsis leidyi

Early embryonic development of Mnemiopsis leidyi.  The early cleavage planes are unipolar - initiating at one end of the cell.  The first two cleavage events mark the primary axes; the plane of first cleavage defines the oral-aboral axis, the second cleavage plane defines the ‘tentacular’ axis.

Members of the phylum Ctenophora [comb bearing] are distinguished by a signature synapomorphy, the modified giant cilia organized in repeating rows of ‘ctene plates’ that provide them with their principal means of locomotion.

Metachronal beating of a single row of  ciliary comb plates.

Metachronal beating of a single row of  ciliary comb plates viewed laterally.

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The lobate ctenophore, Mnemiopsis leidyi.