Pleodorina W.R.Shaw, 1894: 282
Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Viridaeplantae
Phylum Chlorophyta
Class Chlorophyceae
Order Volvocales
Family Volvocaceae
Holotype species: Pleodorina californica W.R.Shaw
Original publication and holotype designation: Shaw, W.R (1894). Pleodorina, a new genus of the Volvocineae. Bot. Gaz. 19: 279-283. pi. 27. Botanical Gazette 19: 279-283, pl. XXVII.
Taxonomic status: currently recognized as a distinct genus.
Description: Colonies spherical, ovoid or ellipsoidal, containing 32, 64 or 128 cells arranged radially at periphery of a gelatinous matrix. Colonies with small, obligately somatic cells mainly at anterior pole, and large reproductive cells (gonidia) in remaining portion. The matrix with or without individual sheaths; this is species dependent. Cells spherical or ovoid, each with two equal flagella, a stigma, more than several contractile vacuoles on the surface, and a massive cup-shaped chloroplast. Chloroplasts of somatic cells with a single basal pyrenoid whereas reproductive cells have multiple ones. Stigmata of anterior cells are larger than in posterior cells. Asexual reproduction by autocolony formation; each reproductive cells of the colony divides successively to become a plakea, which inverts to develop a daughter colony. Sexual reproduction anisogamous, forming walled aplanozygotes. Reproductive cells divide successively to become sperm packets (bundles of male gametes) or develop into female gametes without cell division. The germinating zygote gives rise to a single biflagellate gone cell. Pleodorina is cosmopolitan in freshwater.
Comments: Pleodorina was originally described with a single species, P. californica, and distinguished from Eudorina by the specialization of reproductive cells in part of the colony. Later, various concepts for Pleodorina and Eudorina were proposed, including the synonymy of Pleodorina in Eudorina, but the two genera were eventually distinguished based on the presence or absence of obligately somatic cells, respectively. Abundant bacteria-like endosymbionts were observed in the cytoplasm of P. japonica using DAPI and electron microscopy.
NCBI Nucleotide Sequences
Numbers of names and species: There are 7 species (and infraspecific) names in the database at present, of which 5 have 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):
Pleodorina californica W.R.Shaw C - type
Pleodorina illinoisensis Kofoid C
Pleodorina indica R.C.Starr & J.Zeikus S
Pleodorina indica (Iyengar) H.Nozaki C
Pleodorina japonica H.Nozaki U
Pleodorina starrii H.Nozaki, F.D.Ott & A.W.Coleman C
Pleodorina thompsonii F.D.Ott, H.Nozaki & A.W.Coleman C
Information contributed by: H. Nozaki. The most recent alteration to this page was made on 8 Jun 2009 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.
