Eucampia Ehrenberg, 1839

Holotype species: Eucampia zodiacus Ehrenberg

Original publication and holotype designation: Ehrenberg [C.G.] (1839). Über jetzt wirklich noch zahlreich lebende Thier-Arten der Kreideformation der Erde. Bericht über die zur Bekanntmachung geeigneten Verhandlungen der Königl. Preuß. Akademie der Wissenschaften zu Berlin 1839: 152-159.

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Description: Cells interlocking by two apical elevations to form chains, often curved in spirals due to slightly unequal development of the valves and girdle. Plastids many, discoid. A common marine planktonic genus of only 5 species (VanLandingham, 1969). Valve elliptical to linear. Rows of large areolae radiate from a central annulus within which a rimoportula and some areolae are located. The vela are complex cribra, resembling those in Achnanthes and Isthmia. Apical elevations flattened, with rows of small pores separated by ridges which may or may not cross the central area; this structure is termed an ocellus and certainly functions as such, but its structure is rather unlike that of the ocelli in, for example, the Eupodiscaceae; it does, however, resemble that of Cerataulina. Simple pores occur in the valve framework particularly where new rows are intercalated. Internally the valve is without any special differentiation except that the single central rimoportula protrudes; according to Ross, Sims & Hasle (1977), there is slight development of internal costae. Copulae numerous, areolate, split and ligulate. The areolae are smaller and with more regular pores than on the valves. Resting spores are formed inside vegetative cells and according to Hoban et al. (1980), the first valve has ocelli and coarser valves, while the second has pointed processes but no ocellus. These spores (of E. balaustium) have been described in the literature as separate species of Eucampia. See also Steyaert & Bailleux (1975a, b) who also report that valves at the ends of filaments do not have ocelli - these may therefore be separation valves.

The most recent alteration to this page was made on 2020-01-31 by M.D. Guiry.

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

Most recent taxonomic treatment adopted: Nikolaev, V.A., Kociolek, J.P., Fourtanier, E., Barron, J.A. & Harwood, D.M. (2001). Late Cretaceous diatoms (Bacillariophyceae) from the Marca Shale member of the Moreno Formation, California. Occasional Papers of the California Academy of Sciences 152: 1-119, 39 plates.

Comments: This genus is very close to Climacodium and Hemiaulus but there are no spines at the apices of the elevations as in Hemiaulus and a ridged ocellus is prominent as in Eucampiua but not in Hemiaulus. Ross et al. (1977) discuss the relationships in more detail and report that E. balaustium is congeneric with the type species E. zodiacus. Syvertsen & Hasle (1983) give a detailed account of Eucampia with which the genus Muelleria is synonymous.

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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.

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M.D. Guiry in Guiry, M.D. & Guiry, G.M. 31 January 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 14 June 2024

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