in taxon subdivision of digestive tract holothurian cloaca 2026-10-13T20:58:56Z https://github.com/obophenotype/uberon/issues/3775 cloaca Distinct from 'cloaca' (UBERON:0000162), which is restricted to vertebrates and is defined as a common chamber receiving both the intestine and the excretory system; the holothurian structure is called a cloaca for its terminal position in the gut, and no homology with the vertebrate cloaca is asserted. After evisceration, the respiratory trees regenerate from cells of the coelomic and luminal epithelia of the cloaca (PMID:19238446). A subdivision of the digestive tract that is the posterior-most region of the gut of a sea cucumber, and from the dorsal wall of whose anterior part the respiratory trees arise. The germ layer of origin is unresolved. The holothurian cloaca is traditionally held to be ectodermal and lined by a cuticular epithelium, but its anterior part has been reported to be lined by enterocytes and to lack a cuticle, suggesting an endodermal origin for that part. No developmental relationships are asserted for this reason. UBERON:1200386