Microanatomy of the trophosome region of Paracatenula cf. polyhymnia (Catenulida, Platyhelminthes) and its intracellular symbionts.

ABSTRACT: Marine catenulid platyhelminths of the genus Paracatenula lack mouth, pharynx and gut. They live in a symbiosis with intracellular bacteria which are restricted to the body region posterior to the brain. The symbiont-housing cells (bacteriocytes) collectively form the trophosome tissue, which functionally replaces the digestive tract. It constitutes the largest part of the body and is the most important synapomorphy of this group. While some other features of the Paracatenula anatomy have already been analyzed, an in-depth analysis of the trophosome region was missing. Here, we identify and characterize the composition of the trophosome and its surrounding tissue by analyzing series of ultra-thin cross-sections of the species Paracatenula cf. polyhymnia. For the first time, a protonephridi

SUBMITTER: Leisch N 

PROVIDER: S-EPMC3213344 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature