only in taxon in taxon develops from Chordata Tunicata somite http://upload.wikimedia.org/wikipedia/commons/6/64/Gray19_with_color.png currently classified as an epithelial vesicle, consistent with EHDAA2 and https://github.com/obophenotype/uberon/wiki/The-neural-crest. Consider making 'somitic mesoderm' a separate term and correlate with regionalization processes. Consider moving ZFA term to 'trunk somite' as it is part of the trunk When the somite becomes segmented from the segmental plate, it is composed of an epithelial sac enclosing mesenchymal somitocoel cells. Thereafter the somite differentiates into two parts, the ventro-medial mesenchymal sclerotome and the dorso-lateral epithelial dermomyotome. This change in the epithelial somite depends on surrounding tissue [PMID:15906248] somitic presomitic mesoderm developing anatomical structure epithelial vesicle