Plagiotropis Pfitzer, 1871, nom. illeg.

Holotype species: Plagiotropis baltica Pfitzer

Original publication and holotype designation: Pfitzer, E. (1871). Untersuchungen über Bau und Entwicklung der Bacillariaceen (Diatomaceen). In: Botanische Abhandlungen aus dem Gebiet der Morphologie und Physiologie Bd 2. pp. [i]-vi, [1]-189, plus 6 pls. Bonn: bei Adolph Marcus.

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Description: Frustules rather hyaline; girdle view mostly bilobate (slightly to distinctly), often exhibiting a distinct central nodule and two terminal thickenings at each extremity (valvar pseudosepta). Valves elongate, lanceolate to elliptical-lanceolate, tapering to narrow extremities; some species with very narrow, pointed ends. Central or eccentric keel present with simple raphe system along the keel apex; keel straight, often considerably elevated above the valve surface into two distinct wings. Valve body may be further contoured with one to several longitudinal folds or ridges. Central area small, orbicular to large and somewhat asymmetrical, or transversely narrow-lanceolate. Striae mostly transversely oriented, sometimes appearing radiate toward the valve extremities; composed of individual puncta which can be arranged in longitudinal rows, decussating rows, or may show no pattern of arrangement.

Information kindly contributed by Patrick & Reimer (1975: 7). but may now be outdated.

Taxonomic status: The taxonomic or nomenclatural status (or both) of this entity is in some way unresolved and requires further investigation.

Gender: This genus name is currently treated as feminine.

Most recent taxonomic treatment adopted: Paddock, T.B.B. (1988). Plagiotropis Pfitzer and Tropidoneis Cleve, a summary account. Bibliotheca Diatomologica 16: 1-152, 38 pls.

Comments: Round, Crawford & Mann (1990: 163) record this family as belonging to the suborder Naviculineae. Scott & Thomas (2005: 158) record this genus as being a member of the Family Naviculaceae. These authors also use the alternate spelling of Plagiotropus.

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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=43741

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 07 August 2024. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024