Denticulopsis Simonsen, 1979
Holotype species: Denticulopsis hustedtii (Simonsen ex T.Kanaya) Simonsen
Original publication and holotype designation: Simonsen, R. (1979). The diatom system: ideas on phylogeny. Bacillaria 2: 9-71, 3 figs, 3 appendices.
Request PDFFossil: 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: Frustules rectangular in girdle view. Plastids not described. Forms short chains by contact of neighboring valve surfaces. Valves short linear or linear-elliptic with bluntly-rounded ends, bacillate. Striae consist of transapical rows of puncta. Size and arrangement of puncta variable, ranging from 10 to > 30 in 10 &m. Puncta may occur in several regular rows with quincunx arrangement, or irregular rows or no discernible arrangement, sometimes only on mantle and valve margins. Larger puncta possess rotae. Mantle striae usually more regular, consisting of several rows of puncta in quincunx. Striae separated by costae, which are flat on valve exterior and thickened on interior ("secondary pseudosepta" according to some authors). At intervals of 1-5, costae extend deeper into valve interior as pseudosepta which may be greatly thickened (thickened portions sometimes referred to as "crossbars"). Pseudosepta may be deeper than the valve to produce a marginal crescent-shaped buttress. Raphe marginal, lying at boundary of valve face and mantle. Raphe continuous or interrupted at the center, slightly curved at each apex. Raphe systems of a frustule on opposite margins. Inner raphe system simple or fibulate with fibulae corresponding to costae, in some species one costa will branch at margin to form 2 fibulae. Cingulum consists of one copula and 1-3 pleurae. Copula closed or with a slit, hyaline or with a row of puncta. If thickened pseudosepta present, copula has arches corresponding to the flared ends of the pseudosepta, often partially fused to them, thus giving the impression of septa. Pleurae with a slit, smooth. Marine planktonic, most common in North Pacific but occasionally found in tropical zones of all oceans. One living species (D. seminae) and 12-15 fossil forms, all Neogene marine. Differs from Denticula in having the raphe system marginal and lacking a keel; also the extreme thickenings of the pseudosepta. Differs from Nitzschia in possessing multiseriate striae and pseudosepta, and in lacking a raphe keel. Most similar to Fragilariopsis, from which it differs by possessing pseudosepta. Akiba and Yanagisawa (1986) have proposed division into 3 genera distinguished as follows: Crucidenticula (large puncta with rotae; transapical costae sometimes absent on valve face and present only at margins; raphe interrupted), Denticulopsis (puncta of intermediate size, simple; raphe interrupted), and Neodenticula (very fine puncta; marginal costae only on raphe-bearing margin, formed by branching of transapical costae and creating fibulae; raphe continuous).
Information contributed by: C. Sancetta. The most recent alteration to this page was made on 2022-10-16 by Salvador Valenzuela Miranda.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Most recent taxonomic treatment adopted: Round, F.E., Crawford, R.M. & Mann, D.G. (1990). The diatoms biology and morphology of the genera. pp. [i-ix], 1-747. Cambridge: Cambridge University Press.
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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=45395
Citing AlgaeBase
Cite this record as:
Salvador Valenzuela Miranda in Guiry, M.D. & Guiry, G.M. 16 October 2022. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 25 April 2024
