Back
Hystrichosphaera crassimurata
Hystrichosphaera crassimurata Davey and Williams, 1966
Originally Hystrichosphaera, subsequently Spiniferites, thirdly Pterodinium.
Taxonomic senior synonym: Cymatiosphaera (as Spiniferites?, now Pterodinium) pterota, according to Kjellström (1973, p.44) and Pavlishina (1990, p.95).
Taxonomic junior synonym (at specific rank): Hystrichosphaera cingulata var. polygonalis, according to Clarke et al. (1968, p.181) — however, Paul et al. (1994, p.722) retained Hystrichosphaera cingulata var. polygonalis (as Pterodinium cingulatum subsp. polygonale).
Holotype: Davey and Williams, 1966, pl.1, fig.11
Locus typicus: Fetchum Mill, Surrey, England
Stratum typicum: Cenomanian
Original diagnosis: Davey and Williams, 1966, p. 39-40
A species of Hystrichosphaera with well developed crests. Gonal processes reduced to supports for crests. Periphragm of each reflected plate area smooth and extremely thickened. Reflected tabulation typical for genus.
Dimensions: holotype: diameter of central body 44 by 46 µm, height of crests up to 14 µm. Range: diameter of holotype 36-46 µm, height of crests up to 14 µm.
Original description: Davey and Williams, 1966, p. 40
Only gonal processes are present and these do not extend beyond the limits of the crests. The processes are usually simple but may terminate in a small bifurcation. The periphragm of the crests is typically slightly granular whereas that of the central body is always smooth. The thickened periphragm on the central body may be up to 3.5 µm thick.
Affinities:
Davey and Williams, 1966, p. 40: High crests enclosing the processes are present in two other species of Hystrichosphaera: H. cingulata (Wetzel) and H. pterota (= Cymatiosphaera pterota Cookson & Eisenack). However H. crassimllrata sp. nov. is readily distinguishable from these two species by the thickened areas of the periphragm on the central body.
Originally Hystrichosphaera, subsequently Spiniferites, thirdly Pterodinium.
Taxonomic senior synonym: Cymatiosphaera (as Spiniferites?, now Pterodinium) pterota, according to Kjellström (1973, p.44) and Pavlishina (1990, p.95).
Taxonomic junior synonym (at specific rank): Hystrichosphaera cingulata var. polygonalis, according to Clarke et al. (1968, p.181) — however, Paul et al. (1994, p.722) retained Hystrichosphaera cingulata var. polygonalis (as Pterodinium cingulatum subsp. polygonale).
Holotype: Davey and Williams, 1966, pl.1, fig.11
Locus typicus: Fetchum Mill, Surrey, England
Stratum typicum: Cenomanian
Original diagnosis: Davey and Williams, 1966, p. 39-40
A species of Hystrichosphaera with well developed crests. Gonal processes reduced to supports for crests. Periphragm of each reflected plate area smooth and extremely thickened. Reflected tabulation typical for genus.
Dimensions: holotype: diameter of central body 44 by 46 µm, height of crests up to 14 µm. Range: diameter of holotype 36-46 µm, height of crests up to 14 µm.
Original description: Davey and Williams, 1966, p. 40
Only gonal processes are present and these do not extend beyond the limits of the crests. The processes are usually simple but may terminate in a small bifurcation. The periphragm of the crests is typically slightly granular whereas that of the central body is always smooth. The thickened periphragm on the central body may be up to 3.5 µm thick.
Affinities:
Davey and Williams, 1966, p. 40: High crests enclosing the processes are present in two other species of Hystrichosphaera: H. cingulata (Wetzel) and H. pterota (= Cymatiosphaera pterota Cookson & Eisenack). However H. crassimllrata sp. nov. is readily distinguishable from these two species by the thickened areas of the periphragm on the central body.