Lauderia Cleve, 1873
Holotype species: Lauderia annulata Cleve
Original publication and holotype designation: Cleve, P.T. (1873). Examination of diatoms found on the surface of the Sea of Java. Bihang till Kongliga Svenska Vetenskaps-Akademiens Handlingar 1(11): 1-13, 3 pls.
Description: Cells shortly cylindrical, joined to form straight filaments. In girdle view the well-rounded valves give a beaded appearance to the filament. Plastids numerous, discoid, lobed. Common and widespread in the phytoplankton of the oceans. A small genus of two (possibly five) recorded species but all reduced to a single taxon by Hasle (1974). Valves very delicate, with fine costae radiating from a central annulus; fine pores penetrate the basal layer between the costae. Around the circumference only, anastomosing costae are present externally, producing a weakly loculate structure. The central area of the valve may be plain or indistinctly porose. Around the circumference there are numerous fultoportulae in several ranks; a few fultoportulae also occur scattered on the valve face. The fultoportulae have well-developed external tubes, whose rims are slightly serrate and whose bases merge into the framework in the marginal region. Internally the fultoportulae are small and have only feebly developed buttresses. A ring of longer, thinner processes is also present at the boundary between the loculate and costate regions but these do not arise from fultoportulae and are probably occluded. These are the sines referred to by Gran (1900) which in TEM can be seen to be solid structures. A single fairly large rimoportula is located near the edge of the valve, but just within the costate area. Copulae loculate as in the marginal region of the valve, although they are unusual in that the loculae are much larger than on the valve; split.The most recent alteration to this page was made on 2011-10-19 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Most recent taxonomic treatment adopted: Stoermer, E.F. & Julius, M.L. (2003). Centric Diatoms. In: Freshwater Algae of North America. (Wehr, J.D. & Sheath, R.G. Eds), pp. 559-594. San Diego: Academic Press.
Comments: Scott & Thomas (2005: 84) record this genus as a member of the Family Thalassiosiraceae. This is a very characteristic genus which cannot be closely allied to other genera in the Thalassiosirales; hence our proposal to place it within its own family.
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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.
Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=44416
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 19 October 2011. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 30 September 2022