Geminigera D.R.A.Hill, 1991

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.

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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.

Information contributed by: D.R.A. Hill. The most recent alteration to this page was made on 2017-05-26 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Most recent taxonomic treatment adopted: Kawai, H. & Nakayama, T. (2015). Introduction (Heterokontobionta p.p.), Cryptophyta, Dinophyta, Haptophyta, Heterokontophyta (except Coscinodiscophyceae, Mediophyceae, Fragilariophyceae, Bacillariophyceae, Phaeophyceae, Eustigmatophyceae), Chlorarachniophyta, Euglenophyta. In: Syllabus of plant families. Adolf Engler's Syllabus der Pflanzenfamilien. Ed. 13. Phototrophic eukaryotic Algae. Glaucocystophyta, Cryptophyta, Dinophyta/Dinozoa, Haptophyta, Heterokontophyta/Ochrophyta, Chlorarachnniophyta/Cercozoa, Chlorophyta, Streptophyta p.p. (Frey, W. Eds), pp. 11-64, 103-139. Stuttgart: Borntraeger Science Publishers.

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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.

Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=45542

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 26 May 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024