Gyrosigma acuminatum (Kützing) Rabenhorst 1853

Publication Details
Gyrosigma acuminatum (Kützing) Rabenhorst 1853: 47, pl. 5: fig. 5a

Published in: Rabenhorst, L. (1853). Die Süsswasser-Diatomaceen (Bacillarien.): für Freunde der Mikroskopie. pp. [1]-xii, [1]-72, 10 plates [I–X]. Leipzig: Eduard Kummer.

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Type Species
The type species (holotype) of the genus Gyrosigma is Gyrosigma hippocampus Hassall.

Status of Name
This name is of an entity that is currently accepted taxonomically.

Basionym
Frustulia acuminata Kützing

Type Information
Type locality: süssen Wassern [sweet waters, presumably Germany]; (Kützing 1834: 555) Notes: G.C. 14188a, ANSP and BM 78084 (syntype) [Sterrenburg pers.comm.]

Origin of Species Name
Participle A (Latin), acuminate, i.e. tapering gradually or abruptly from inwardly curved sides into a narrow point (Stearn 1983).

General Environment
This is a freshwater species.

Description
Valve moderately sigmoid, slender to somewhat more broadly lanceolate with fairly obtuse or subacute ends, 70-180 µm long, 12-24 µm wide. Raphe sternum with minimal double curvature, almost straight for half its length, practically median except slightly eccentric near the ends, raphe angle +3 to +8 degrees. Central raphe fissures crook-shaped, oppositely deflected to either the convexity or concavity of their raphe sternum (dimorphic deflection type). Central area oval, not rotated. Terminal areas unilaterally dilated funnels in semilateral position. A crescent of minute apical microforamina runs around the apex in the hyaline terminal area, at the limit of visibility in the LM. Longitudinal striae 19-24 in 10 µm, markedly closer together at the margin of the valve (SEM), transverse almost equally fine or very slightly coarser.

Habitat
Very common in fresh to very slightly brackish waters, probably cosmopolitan and personally (Sterrenburg) observed in samples from Europe, the USA, New Zealand and South Africa.

Created: 11 April 2002 by M.D. Guiry.

Last updated: 12 April 2024

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Linking to this page: https://www.algaebase.org/search/species/detail/?species_id=32031

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 12 April 2024. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 24 November 2024

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