NAME Palaeoamphisphaerella tankensis
AGE Eocene.   AGE span: 55.8...33.9 mya
K&J CLASSIFICATION (2000) Fungi Imperfecti, Amerosporae.
FIGURE(S)
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Pl.3fig.54.jpg
FIGURE REFERENCE Norris G. 1986. Systematic and stratigraphic palynology of Eocene to Pliocene strata in the Imperial Nuktak C-22 well, Mackenzie Delta Region, District of Mackenzie, N.W.T.; Geological Survey of Canada Bulletin, Bulletin 340, 89 p.
SPECIES, AUTHORITY P. tankensis (Norris) Kalgutkar & Jansonius 2000
LOCATION Imperial Nuktak C-22 Well, Mackenzie Delta Region, District of Mackenzie, N.W.T., Canada.
ORIG DESCRIPTION* A species of Imprimospora with an equatorial zone of parallel fissures enclosed between two shadow bands. One or two sub-apical furrows present. Unicellate, ovoidal fungal spores. Central part of cell with 7 or 8 parallel fissures up to 0.5 µm wide, extending longitudinally between two transverse, 1-2 µm wide shadow bands. Spore wall levigate, approximately 0.25-0.5 µm thick, except where thickened up to 1 µm under shadow bands. Sub-apically one or both ends of spore are ruptured irregularly or along arcuate furrows. Spore length 24-36 µm; spore width 11-17 µm.
COMMENTS* Some specimens do not show shadow bands (pl. 2, fig. 22) and may be an ontogenetic stage or a separate species.
PUBLICATION REFERENCE Norris G. 1986. Systematic and stratigraphic palynology of Eocene to Pliocene strata in the Imperial Nuktak C-22 well, Mackenzie Delta Region, District of Mackenzie, N.W.T.; Geological Survey of Canada Bulletin, Bulletin 340, 89 p.
K&J REMARKS Palaeoamphisphaerella pirozynskii, the type species of the genus described by Ramanujam & Srisailam (1980), appears to be similar in general and diagnostic morphology to Imprimospora tankensis, as described by Norris (1986), the type of Imprimospora. The characteristic central part of the spore is described by Ramanujam & Srisailam as multiporate with 8-10 equatorial, equidistant pores with prominently thickened margin, whereas Norris describes it as having 7 or 8 parallel fissures, extending longitudinally between two transverse, wide 'shadow bands.' Both species are regarded as unicellular and aseptate. Kalgutkar and Jansonius (2000) therefore treat Imprimospora as a junior synonym of Palaeoamphisphaerella, and here transfer its type species to the latter genus.
TYPE
ALL NAMES (Including synonyms) Imprimospora tankensis Norris 1986, p. 22, pl. 2, figs. 20-21.; Palaeoamphisphaerella tankensis
SERIAL NUMBER 1181
PUBLIC COMMENTS
 *For source, see Publication Reference.