NEW GENERA OF FRESHWATER CRYPTOMONADS FROM COLORADO

Electron microscopic examinations of numerous isolates from Colorado lakes and reservoirs have revealed several new genera and species. Based on the furrow/gullet variations and the structure of the periplast, four new genera are proposed. These new genera and their characteristics are as follows. The first genus has a furrow without a gullet, and it has oval periplast plates. There are two chloroplasts per cell and two nucleomorphs located anterior to the chloroplasts in the periplastidial compartment. Pyrenoids are lacking. Chloroplasts contain phycoerythrin 566. The second genus is similar in shape and structure to Plagioselmis, but it has small rectangular plates rather than hexagonal plates. There is one dorsal chloroplast per cell, with a single stalked pyrenoid, which is not traversed by thylakoids and associated with two starch plates. The nucleomorph is posterior to the pyrenoid and is located between the nucleus and pyrenoid. Chloroplasts contain phycoerythrin 566. The third genus lacks a gullet and furrow and has an inner periplast sheet. Cells have two chloroplasts without pyrenoids, and the chloroplasts contain phycoerythrin 566. The nucleomorphs are located in the anterior portion of the plastidial compartment. The fourth genus is blue‐green in color, it lacks a furrow/gullet, and the internal and surface periplast components consist of hexagonal plates. Cells have a large pyrenoid that protrudes ventrally into the cytoplasm and is traversed by numerous paired thylakoids. The nucleomorph is situated lateral to the pyrenoid. Chloroplasts contain phycocyanin 645. This cryptomonad was previously identified as Chroomonas pochmanni, and it is mixotrophic.