Volvulina Playfair, 1915: 337
Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Viridaeplantae
Phylum Chlorophyta
Class Chlorophyceae
Order Volvocales
Family Volvocaceae
Holotype species: Volvulina steinii Playfair
Taxonomic status: currently recognized as a distinct genus.
Description: Colonies ovoid or spherical, containing 16 cells embedded in the periphery of a gelatinous matrix, forming a hollow structure. Cells lenticular or hemispherical, each with two equal flagella, a stigma, two contractile vacuoles at the base of flagella or many contractile vacuoles scattered on the cell surface, a massive cup-shaped chloroplast without pyrenoids or with one in the bottom or brim. Stigmata in anterior cells larger than in posterior cells. Asexual reproduction by autocolony formation; each cell of the colony develops into a daughter colony with successive divisions and subsequent inversion. Sexual reproduction by isogametes produced by the escape of each cell of the colony from the gelatinous matrix. Mature aplanozygotes with spiny or smooth cell wall. A single biflagellate gone cell exits the zygote wall upon germination. Volvulina is cosmopolitan but rare; V. steinii collected in freshwater rich in organic matter. Volvulina was initially established with a single species, V. steinii. It was later characterized as having colonies with 16 lenticular cells normally lacking pyrenoids. V. steinii and V. pringsheimii have pyrenoids and can be distinguished by pyrenoid appearance. De novo development of pyrenoids in V. steinii colonies as a function of culture age was studied using light and electron microscopy. V. compacta was recently described from Nepal, and this species was suggested to be related to Pandorina morum. The current concept of Volvulina is based on the presence of hollow colonies with lenticular cells. Vitamin requirements and organic carbon sources were studied in V. steinii and V. pringsheimii; vitamin B12 was required for growth of both species, whereas an organic carbon source was necessary only for V. steinii.
NCBI Nucleotide Sequences
Numbers of names and species: There are 8 species (and infraspecific) names in the database at present, of which 4 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):
Volvulina boldii P
Volvulina compacta H.Nozaki C
Volvulina playferiana Skvortzov P
Volvulina pringsheimii Starr C
Volvulina steinii Playfair C - type
Volvulina steinii var. lenticularis Playfair C
Volvulina steinii var. parvicellula Playfair C
Volvulina steinii var. subreniformis Playfair C
Information contributed by: H. Nozaki. The most recent alteration to this page was made on 17 Oct 2009 by Stephen Cusack.
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.
