Chrompodellid

Chrompodellids are a phylum of unicellular protists containing two functionally different groups: the photosynthetic "chromerids" and the predatory phagotrophic "colpodellids". Like other Alveolata, they present tubular mitochondrial cristae and highly flattened cortical alveoli They feed on bacteria and other protozoa, such as bodonids, chrysomonads, bicosoecids, percolomonads and ciliates. Vitrella autospores, by contrast, start measuring 3 μm and grow up to 40 μm before transforming into sporangia that generate dozens of autospores or zoospores. There are two types of Vitrella zoospores: one is generated by budding from the mother cell and exhibits flagella outside the cytoplasm, the other develops axonemes and flagella within their cytoplasm and are ejected from the mother cell after maturing, though both types lack a pseudo-conoid. Some zoospores fuse, possibly representing a sexual stage in the life cycle. In addition, Vitrella produces vaucheriaxanthin. == Evolution ==

Chrompodellids are the closest living relatives of the apicomplexan parasites, which evolved from a photosynthetic myzozoan ancestor, making chromerids the last remaining photosynthetic members of an otherwise parasitic clade within Alveolata. }}}} == Systematics ==

Taxonomic history In 1993, protozoologist Thomas Cavalier-Smith described the order Colpodellida (under the ICZN, later regularized as Colpodellales in accordance to the ICN) They showed morphological resemblance to colpodellids and other myzozoans. Between 2004 and 2017, Cavalier-Smith retained the classification scheme of Apicomonadea, from which he excluded Perkinsida, leaving only colpodellids and chromerids across multiple orders. In addition, several genera of flagellates were added on the basis of morphological data: Algovora, Microvorax and Dinomonas. (sister group to Vitrella but not formalized as a member of Vitrellaceae) == References ==