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Tanyosphaeridium xanthiopyxides

Tanyosphaeridium xanthiopyxides (Wetzel, 1933b, p.44–45, pl.4, fig.25 ex Deflandre, 1937b, p.77) Stover and Evitt, 1978, p.85. Emendations: Morgenroth, 1968, p.556, as Hystrichosphaeridium? xanthiopyxides; Sarjeant, 1985b, p.142–144, as Tanyosphaeridium xanthiopyxides.

Originally Hystrichosphaera (name not validly published), subsequently Hystrichosphaeridium, thirdly Hystrichosphaeridium?, fourthly Baltisphaeridium (acritarch), fifthly Prolixosphaeridium?, sixthly (and now) Tanyosphaeridium.
Taxonomic junior synonym: Hystrichosphaeridium (as Tanyosphaeridium) magdalium, according to Stover and Evitt (1978, p.85).
The name Hystrichosphaera xanthiopyxides was not validly published in Wetzel (1933b), since the generic name Hystrichosphaera was not validly published until 1937.

Holotype: Wetzel, 1933b, pl.4, fig.25, Morgenroth, 1968, pl.48, fig.5; Sarjeant, 1985b, pl.3, figs.2–3; Dietz et al., 1999, fig.10, no.8.
Locus typicus: Quaternary drift, southern Baltic region
Stratum typicum: . Erratic flint block of Late Cretaceous (probably Maastrichtian) age
Age: Late Cretaceous (?Maastrichtian, according to Sarjeant, 1985b, p.143).
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Original Diagnosis: WETZL 1933, p. 44 (transl.: Sarjeant 1985): Hystrichosphaera xanthiopyxides
"Shell small, cylindrical or oval. 20-30 processes, longer than half the longest shell diameter, almost all stiffly upright, at bases somewhat broadened, at free ends button-shaped or quite briefly branched. - Colour brownish."
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Emended diagnosis: Morgenroth 1968, p. 556 (transl.: Sarjeant 1985): ?Hystrichosphaeridium xanthiopyxides: "Theca elongate-ellipsoidal, thinwalled, with feebly granulate surface. The theca is regularly set with numerous slender, hollow processes, which - distally open - widen into trumpet shapes, whose edges are weakly denticulate or (more commonly) smooth".
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Emended Diagnosis: Sarjeant 1985 p. 142-144
Skolochorate, cryptotabulate cysts having an ellipsoidal to elongate-ellipsoidal ambitus. Processes widely spaced and moderately numerous (ca. 50-60), slender and buccinate, their length exceeding one-third of the longest diameter of complete cysts. Phragma relatively thin but two-layered, the endophragm closing the process bases, which are formed of periphragm only: surface of phragma granular. Archaeopyle apical, type (tA); operculum, or opercular pieces, normally free.

Dimensions. Holotype: length of central body 28 µm, breadth 12 µm, length of processes 13 µm. Range of dimensions of type material (6 specimens); length of central body 28-30 µm, breadth 10-12 µm, length of processes ca. 12-16 µm.

Remarks. Morgenroth"s diagnosis is here further emended, to include mention of process length and number and of archaeopyle style.

This frequently-reallocated species has been recognized much less widely. It is known from the Late Maastrichtian to Danian of north Germany and Denmark (HANSEN, 1977, p. 25, fig. 196), the Maastrichtian of the Grand Banks, offshore eastern Canada (JENKINS et a/., 1974 p.10), the Campanian to Maastrichtian of New Jersey (MAY, 1980), California (DRUGG, 1967) and Texas (ZAITZEFF and CROSS, 1971) and the Maastrichtian of Mexico (HELENES, 1984). This consistency of records indicates that the type material is almost certainly of Maastrichtian date. A record by MERCIER (1938, p. 95) from earlier strata in the Late Cretaceous of the Paris basin is unaccompanied by an illustration and must be viewed with doubt. However, a somewhat similar form, but with a more broadly ellipsoidal central body, has been reported from the Albian of the Paris basin by DAVEY and VERDIER (1971, p. 35, pl. 7, fig. 9 [only]; as T. cf. variecalamum DAVEY and WILLIAMS): this may correspond with MERClER"s form and might well be ancestral to T. xanthiopyxides.
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