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Table 1 Fate of some larval structures during metamorphosis in studied phoronid species

From: Metamorphic remodeling of morphology and the body cavity in Phoronopsis harmeri (Lophotrochozoa, Phoronida): the evolution of the phoronid body plan and life cycle

Name of studied species and author of study Fate of larval organs
Preoral lobe Tentacles Telotroch Protocoel
“Actinotrocha A” (probably larva of Phoronopsis harmeri) [22] transforms into small unpaired remnant that gives rise to the adult epistome completely turns into definitive tentacle retained for at least 4 days and then degenerates ? “…the existence of a coelomic epithelium in the juvenile epistome is impossible confirm or deny…”
Phoronopsis harmeri [15, 26, 27, herein] is partly retained as two lateral remnants, which contribute to the future formation of the epistome undergo partial reduction: the postroral ciliated band degenerates. Larval tentacles change neither in length nor number retained for 9 days and then disappears retained, but greatly reduces in size
Phoronis muelleri [23, 35] retained as fold of the larval episphaere near the mouth and then turns into epistome completely destroyed; adult tentacles arise from anlagen of definitive tentacles, which are located under the larval is drawn into the digestive tract and becomes hindgut cells, which form the lining of the preoral lobe are completely retained and give rise to the definitive protocoel
Phoronis muelleri [39] ? completely destroyed; adult tentacles arise from anlagen of definitive tentacles, which are located under the larval is drawn into the digestive tract and becomes hindgut protocoel is present neither in larva nor adult
Phoronis psammophilla [24] retained as fold of the larval episphaere near the mouth and then turns into epistome completely destroyed; adult tentacles arise from anlagen of definitive tentacles, which are located under the larval retained for several days and then disappears ?
Phoronis pallida [25] completely destroyed undergo great cellular death. Accordingly to figures, the length and number of larval tentacle greatly reduce. Definitive tentacles apparently arise from proximal portions of larval tentacles. ? can not be observed by SEM in juvenile just after the completion of metamorphosis. Apparently, the telotroch is drawn into the digestive tract ?
“Actinotrocha C” [38] completely destroyed thickened proximal portions are retained through metamorphosis and give rise to definitive tentacles is drawn into the digestive tract ?
  1. ?” – the fate of larval organs unknown or not described in detail