The morphology of Protoopalina pomacantha, n. sp., symbiont in the rectum of the angelfishes, Pomacanthus zonipectus and Holacanthus passer. A light,scanning electron and transmission electron microscopic study

Protoopalina pomacantha n. sp, were discovered with fecal debris from the l arge hind gut chamber (rectum) of the Angelfishes, Pomacanthus zonipectus, and Holacanthus passer, collected from the Sea of Cortez near La Gaviota Is land, Mexico. To describe this species, specimens from each host were studi ed with both light and electron microscopy, It is generally similar to othe r fish inhabiting protoopalines. The body is curved, contains a small anter ior fair, and a pointed posterior end-barren of flagella. It has desmose fi brils interconnecting kinetosomes and electron dense substance within kinet osomes. The form of it's somatic kinetosomal desmose is similar to at least one species of the genus, Protoopalina, but differs from several. The fair kinetosomal and desmose ultrastructure is similar to several opalinids, Th is is judged to be a new species based on its host, components within the k inetosomal lumen, and desmose structures. Bacterial ectosymbionts are often found attached, in shallow pits, within a kinety and between flagella.