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Mendicodinium woodhamensis
Mendicodinium woodhamensis Drugg, 1978
Taxonomic senior synonym: Thuledinium (as Mendicodinium) groenlandicum, according to Riley and Fenton (1982, p.200).
Holotype: Drugg, 1978, pl.6, fig.1
Isotypes: Drugg, 1978, pl.5, figs.10,11, pl.6, fig.2
Locus typicus: Woodham Brick Pit near Aylesbury, England
Stratum typicum: Late Callovian
Original description: Drugg, 1978, p. 70
Subspherical cysts slightly flattened at the poles. The autophragm is thin (ca. 0.5 Ám) and is smooth to very faintly shagreen. The cyst breaks equatorially into equal parts with the epicyst and hypocyst tending to remain attached together by means of a helicoidal strap. When completely detached the epicyst exhibits a parasulcal tongue and the hypocyst has a parasulcal notch. The diameter ranges from 65 to 80 Ám with most specimens measuring about 75 Ám.
Affinities:
Drugg, 1978, p. 70: The type species M. reticulatum differs primarily in being reticulate rather than smooth. It also exhibits a clearly visible parasulcal depression and a vaguely expressed paracingular depression. The new species M. woodhamensis does not show any sign of either parasulcal or paracingular depressions. The lack of such features does not seem at present sufficient justification to erect a new genus. This new species bears a resemblance to Thuledinium groenlandicum Pocock and Sarjeant, 1972. The morphological interpretation given by Pocock and Sarjeant, however, is completely different so the seeming resemblance is apparently illusory.
Taxonomic senior synonym: Thuledinium (as Mendicodinium) groenlandicum, according to Riley and Fenton (1982, p.200).
Holotype: Drugg, 1978, pl.6, fig.1
Isotypes: Drugg, 1978, pl.5, figs.10,11, pl.6, fig.2
Locus typicus: Woodham Brick Pit near Aylesbury, England
Stratum typicum: Late Callovian
Original description: Drugg, 1978, p. 70
Subspherical cysts slightly flattened at the poles. The autophragm is thin (ca. 0.5 Ám) and is smooth to very faintly shagreen. The cyst breaks equatorially into equal parts with the epicyst and hypocyst tending to remain attached together by means of a helicoidal strap. When completely detached the epicyst exhibits a parasulcal tongue and the hypocyst has a parasulcal notch. The diameter ranges from 65 to 80 Ám with most specimens measuring about 75 Ám.
Affinities:
Drugg, 1978, p. 70: The type species M. reticulatum differs primarily in being reticulate rather than smooth. It also exhibits a clearly visible parasulcal depression and a vaguely expressed paracingular depression. The new species M. woodhamensis does not show any sign of either parasulcal or paracingular depressions. The lack of such features does not seem at present sufficient justification to erect a new genus. This new species bears a resemblance to Thuledinium groenlandicum Pocock and Sarjeant, 1972. The morphological interpretation given by Pocock and Sarjeant, however, is completely different so the seeming resemblance is apparently illusory.