Platydorina Kofoid, 1899: 435
Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Viridaeplantae
Phylum Chlorophyta
Class Chlorophyceae
Order Volvocales
Family Volvocaceae
Holotype species: Platydorina caudata Kofoid
Original publication and holotype designation: Kofoid, C.A. (1899). Plankton studies. III. On Platydorina, a new genus of the family Volvocidae, from the plankton of the Illinois River. Bulletin of the Illinois State Laboratory of Natural History 5(9): 419-440, pi. 38.
Taxonomic status: currently recognized as a distinct genus.
Description: Colonies flattened, slightly twisted and horseshoe-shaped with three to five posterior projections, each colony containing 16 or 32 cells arranged in one layer and oriented in different directions in a gelatinous matrix. Cells spherical or pear-shaped, each with two equal flagella, a stigma, two contractile vacuoles at the base of flagella and a massive cup-shaped chloroplast with a single basal pyrenoid. Asexual reproduction by autocolony formation, each cell of the colony dividing successively to form a plakea, which becomes a daughter colony after inversion and subsequent intercalation. Sexual reproduction anisogamous with sperm packets (bundles of male gametes). Platydorina is a freshwater genus only found in USA. Effects of various vitamins, nitrogen and carbon sources and pH on growth were investigated; only vitamin B12 stimulated growth, and a carbon source was required for anaerobic growth. A sulfated polysaccharide present in gelatinous matrix. Ultrastructure of flagellar apparatus suggested that Platydorina evolved from a Chlamydomonas-like ancestor.
NCBI Nucleotide Sequences
Numbers of names and species: There is only one species or infraspecific name in the database at present, which has been flagged as currently accepted taxonomically.
Names: ('C' indicates a name that is currently accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):
Platydorina caudata Kofoid C - type
Information contributed by: H. Nozaki. The most recent alteration to this page was made on 14 May 2010 by M.D. Guiry.
Contributors
Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera,
organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA)
and intended to be published in CD format.
These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above.
The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.
Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.
