Amphorotia D.M.Williams & G.Reid, 2006

Holotype species: Amphorotia clevei (Grunow) D.M.Williams & G.Reid

Original publication and holotype designation: Williams, D.M. & Reid, G. (2005). Amphorotia nov. gen., a new genus in the family Eunotiaceae (Bacillariophyceae), based on Eunotia clevei Grunow in Cleve & Grunow. Diatom Monographs 6: 1-153.

Fossil: This is a genus of fossil species, or a genus with a fossil type species, or a genus the type species of which was originally described as a fossil.

Description: Cells with dorsi-ventral, raphid frustules and bilaterally asymmetrical valves. Frustules arranged in clusters forming colonies; each frustule connected at the same pole, colony appearing in ‘bunches’. Valves arcuate to strongly lunate. Ventral valve margin shallow relative to dorsal margin. Sternum narrow sometimes sharply differentiated, other times diffuse, positioned dorsally, parallel to raphe slit. Striae simple, uniseriate, with small, circular poroids. Raphe slits small, polar, situated mainly on the ventral mantle. Terminal fissures present, extending onto the dorsal margin, terminating in helictoglossa. External valve usually with spines, sometimes small ‘stubs’, other times long, extended spines. Spines situated on the ventral mantle and the dorsal valve margin. Rimportulae present, polar, situated between helictoglossa and polar valve margin. Internal opening usually large and elongate, external opening a simple slit or small hole. Cingulum consisting of 3-5 (in some cases 7?) open, ligulate, copulae, each broad on the dorsal side, narrow on the ventral side. Plastids (probably) single, large, lobed, extending into valve polar areas; centre narrow with interconnecting bridge.

Information contributed by: Original description.. The most recent alteration to this page was made on 2017-11-24 by M.D. Guiry.

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

Most recent taxonomic treatment adopted: Fourtanier, E.J. & Kociolek, J.P. (2009). Catalogue of diatom names: Part II: Abas through Bruniopsis. Occasional Papers of the California Academy of Sciences 156(II): 1-231, 2 figs, 1 table.

Comments: Usually freshwater, occasionally marine or brackish; frustules attached, either epiphytic or episammic. Not known from acid waters (cf. Eunotia Ehrenb., Actinella F. W. Lewis and Semiorbis R.M. Patrick in Patrick & Reimer 1966; Round et al. 1990).

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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=50680

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 24 November 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 04 May 2024