Pseudogomphonema Medlin, 1986

Holotype species: Pseudogomphonema kamtschaticum (Grunow) Medlin

Original publication and holotype designation: Medlin, L.K. & Round, F.E. (1986). Taxonomic studies of marine gomphonemoid diatoms. Diatom Research 1(2): 205-225, 100 figs, 1 table.

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Description: Cells solitary, attached by a short stalk or pad, heteropolar and usually lying in girdle view. Valves linear to linear-lanceolate with broadly rounded or slightly rostrate head poles and more acutely rounded foot poles. Valve face flat in centre or curving uniformly into relatively deep mantles in some species. Striae uniseriate containing apically elongate slit-like pores, occluded by hymenes and opening internally into grooves between strongly developed transapical ribs. Pseudoseptum usually present at the foot pole as a bridge across the valve, which is fused to the helictoglossa leaving an apical chamber that opens to the outside by a row of a number of unoccluded slits; there may also be a chamber at the head pole. Raphe-sternum central, more strongly developed internally on the primary side (i.e. that side of the raphe system that is laid down first, Mann 1984a). Thus, the raphe opens laterally along its length but becomes vertical at the apices and valve centre. Raphe system associated with the head pole only slightly shorter than that at the foot pole. External central raphe endings e*anded, pore-like; internal endings straight, simple, closer together than the external endings. Terminal fissures usually absent at the head pole, hooked to one side at the foot pole. Cingulum containing four open, nonporous bands, the first and third of which are long bands extending nearly the whole length of the valve; the second and fourth are reduced to small segments (ligulae) lying at the foot pole. The partes interiores of bands 2 and 4 are slightly septate to clasp the pseudoseptum at the foot pole.

Origin of description: this description is from the original publication; it may have been modified slightly. The most recent alteration to this page was made on 2019-09-23 by M.D. Guiry.

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.

Comments: Round, Crawford & Mann (1990: 128) record this family as being a member of the Suborder Naviculineae.

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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. 23 September 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 17 August 2022

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