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Description
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Table 2. Comparison of Pseudostaurosira heteropolaris sp. nov and P. oblonga sp. nov. with morphologically similar, congeneric species. Features in bold italic font are defining for each taxon. Feature/speciesP. alvareziae Cejudo-Figueiras, E. Morales & EctorP. americana E. MoralesP. bardii Beauger, C.E. Wetzel & EctorP. heteropolaris sp. nov.P. oblonga sp. nov.Valve dimensions (µm)L: 10-18 W: 3.6-5.0L: 6.0-38.0 W: 4.5-5.0L: 4.0-6.5 W: 3.0-5.5L: 3.0-4.3 W: 2.6-3.3L: 6.9-13.5 W: 3.8-4.8Stria density (in 10 µm)13-1516-1812-1613-1613-14Valve outline; axial area; virgaeElliptic with faintly subrostrate to broadly rounded apices, isopolar; narrowly lanceolate, faintly depressed in external view with respect to virgae, at the same level as virgae in internal view; much wider than striaeLanceolate with cuneate apices, isopolar; linear, at same level as virgae in external and internal view; wider than striaeElliptic to round with broadly rounded ends, isopolar; lanceolate to elliptic, depressed with respect to virgae in external view, at the same level as virgae in internal view; wider than striaeOvoid (sometimes elliptic in small specimens), heteropolar; elliptic, externally slightly depressed with respect to virgae, internally at the same level as the latter; much wider than striaeOblong with widely rounded apices, isopolar; lanceolate, depressed in external and internal view with respect to virgae; wider than striaeAreolae; volae; striaeWide, round to elliptic; well-developed and forming a tight mesh-like structure seen in external and internal view; composed of up to 6 areolae decreasing in size away from valve face/mantle junction, larger areolae contiguous to spines on valve face and mantleWide, round to elliptic; well-developed and forming a tight mesh-like structure visible externally and internally; composed of up to 7 areolae with little size variation away from valve face/mantle junction on valve face, valve mantle with larger areolae varying from elliptic to trapezoidWide, round to elliptic; developed and directed toward valve interior; composed of up to 5 areolae decreasing in size away from valve face/mantle transition, first areola on mantle trapezoid and as large as first areola on valve faceNarrow, elliptic to round or hemispherical at the axial area; well-developed and directed toward valve interior, base of volae wide giving areolae a C-shape; composed by up to 7 areolae decreasing in size away from valve face/mantle transition, first areola on mantle as large as first areola on valve faceNarrow, round to elliptic; well-developed forming a tight mesh-like structure visible externally and internally; composed by up to 6 areolae decreasing in size away from valve face/mantle transition, first areola on mantle trapezoid and largerSpines; stipules; flapsSolid, elliptic base, as wide as basal vimen, flattened body and widely spatulate tips with broad lateral projections; small, conical; incipient on valve face, developed on valve mantleSolid, elliptic base, as wide as basal vimen, cylindrical body with a V-shaped middle opening and openly concave sides, widely spatulate tips with serrate borders; well-developed, almost covering entire first areola on mantle; well-developed, more common on valve mantleSolid, elliptic base, wider than basal vimen, flattened body, triangular in side view, spatulate tips with serrate borders; developed; developed but more frequent on mantle areolaeSolid, elliptic to rectangular base, wider than basal vimen, cylindrical body with concave sides, spatulate tips with pinnatifid bifurcations; absent; absentSolid, elliptic base, as wide as basal vimen, quasi-cylindrical body with concave sides, trapezium-shaped in side view, spatulate tips with wide lateral projections; incipient or absent; little developed on valve face, larger on valve mantleApical pore fields; mantle abvalvar blistersWell-developed, externally with wide round poroids and covered by contorted flaps; small, absent from apicesWell-developed, of cavernous appearance externally, poroids lie at bottom of troughs, internally round poroids open into a shallow depression; well-developed, present at apicesVery reduced almost completely externally covered by flaps, only a pair of poroids can be seen, of cavernous appearance, internally only 3 narrow, round poroids can be seen, which open into a shallow depression; developed and present at apicesVery reduced, externally up to 3 cavernous poroids; small present at apicesReduced, covered by small external flaps, internally opening through few, narrow, unsunk poroids; small absent from apicesReferencesCejudo-Figueiras et al. (2011)Cejudo-Figueiras et al. (2011), Morales et al. (2013b)Beauger et al. (2019)This studyThis study (2021-12-13)
***This entry has been automatically imported via OpenAlex by LIST harvest scripts. Please refer to https://doi.org/10.5281/zenodo.18063690 for the original and latest version of the publication*** (2026-07-01)
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