Geminigera D.R.A.Hill, 1991: 181
Holotype species: Geminigera cryophila (D.L.Taylor & C.C.Lee) D.R.A.Hill
Original publication and holotype designation:Hill, D.R.A. (1991). A revised circumscription of Cryptomonas (Cryptophyceae) based on examination of Australian strains. Phycologia 30: 170-188, 40 figs, 2 tables.
Taxonomic status: currently recognized as a distinct genus.
Description: Free-swimming, ovoid, biflagellate monads; a longitudinal furrow extends posteriorly from the vestibulum and transforms into a sack-like gullet lined with many rows of ejectisomes; a single chloroplast with two pyrenoids and a single nucleomorph, the chloroplast containing the phycobiliprotein Cr-phycoerythrin 545 and varying in color from dull pink to red-brown; with a laminate periplast. Reproduction by simple cell division; sexual reproduction unknown; cyst production unknown, but cells becoming palmelloid in very old cultures. Ultrastructure slightly unusual in that there are two pyrenoids associated with the single chloroplast. The pyrenoids, borne on stalks, are kidney-shaped with two hemispherical starch granules each; they are not traversed by thylakoids. The nucleomorph is not associated with the pyrenoids, but is located in close proximity to the nucleus. The inner periplast component sheet is porous with ejectisome vesicles occupying the pores and providing contact with the plasma membrane. The superficial component comprises an imbricate layer of rosulate scales with interspersed fibrils. The genus is only known from the Antarctic and low temperatures appear to be necessary for its survival. It is, however, extremely halotolerant, being found in both hypersaline lakes and in seawater below the pack-ice.
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):
Throndsen, J. (1996). The planktonic marine flagellates. In: Identifying marine phytoplankton. (Tomas, C.R. Eds), pp. 591-730. San Diego: Academic Press.
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.
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=45542
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 08 December 2013.
Algaebase taxon LSID: urn:lsid:algaebase.org:taxname:5948