Back
Palaeoperidinium amplum
Palaeoperidinium amplum (Harland, 1973) Lentin and Williams, 1976
Originally Lejeunia (an illegitimate name), subsequently Palaeoperidinium; see
also Astrocysta (combination not validly published).
Tax. jr. synonym of Palaeoperidinium cretaceum Pocock, 1962, according to Harker and Sarjeant in Harker et al., 1990.
Holotype: Harland, 1973, pl.84, fig.1
Locus typicus: Southern Alberta, Canada
Stratum typicum: Late Campanian
Original diagnosis: Harland, 1973, p. 673: Lejeunia ampla
Proximate cyst, rhomboidal in shape, probably made up of autophragm only. Test granulate, scabrate and/or reticulate. No tabulation visible. Cingulum usually conspicuous. planar, approximately 5 µm wide, delimited by raised sutures. Single apical horn, distally oblate; two antapical horns one of which generally larger than the other. Archeopyle apical.
Dimensions: Holotype: Length 149.0 µm; breadth 108.0 µm. Range: Length 70.0 (116.3) 154.0 µm; breadth 68.0 (97.0) 108.0 µm. Fifty specimens measured out of a studied population of eighty-nine.
Original description: Harland, 1973, p. 674: Lejeunia ampla
It is possible that a second wall layer, closely adpressed, is present. Only one or two specimens show an apical archeopyle. Norris has observed transapical archeopyles in specimens with the same gross morphology. The Bearpaw specimens appear to have had one or two antapical plates making up the operculum. The antapical horns distally evexate and one was seen to carry small spinules.
Affinities:
Harland, 1973, p. 674: Lejeunia ampla
This species differs from L. tricuspis in lacking the vertical striations, the acuminate antapical horns, and the coarse "ornamentation". Doubt is expressed in the generic assignment because of uncertainties in the nature of the archeopyle in this species and in the genus. The archeopyle as seen in the holotype is perfectly clear and does not appear to be of accidental origin. Evitt (pers. comm.) has commented on the resemblance of the small folds, often observed on the test of these cysts, to growth lines such as those exhibited by Palaeoperidinium pyrophorum (Ehrenberg). Its affinities are unknown.
Originally Lejeunia (an illegitimate name), subsequently Palaeoperidinium; see
also Astrocysta (combination not validly published).
Tax. jr. synonym of Palaeoperidinium cretaceum Pocock, 1962, according to Harker and Sarjeant in Harker et al., 1990.
Holotype: Harland, 1973, pl.84, fig.1
Locus typicus: Southern Alberta, Canada
Stratum typicum: Late Campanian
Original diagnosis: Harland, 1973, p. 673: Lejeunia ampla
Proximate cyst, rhomboidal in shape, probably made up of autophragm only. Test granulate, scabrate and/or reticulate. No tabulation visible. Cingulum usually conspicuous. planar, approximately 5 µm wide, delimited by raised sutures. Single apical horn, distally oblate; two antapical horns one of which generally larger than the other. Archeopyle apical.
Dimensions: Holotype: Length 149.0 µm; breadth 108.0 µm. Range: Length 70.0 (116.3) 154.0 µm; breadth 68.0 (97.0) 108.0 µm. Fifty specimens measured out of a studied population of eighty-nine.
Original description: Harland, 1973, p. 674: Lejeunia ampla
It is possible that a second wall layer, closely adpressed, is present. Only one or two specimens show an apical archeopyle. Norris has observed transapical archeopyles in specimens with the same gross morphology. The Bearpaw specimens appear to have had one or two antapical plates making up the operculum. The antapical horns distally evexate and one was seen to carry small spinules.
Affinities:
Harland, 1973, p. 674: Lejeunia ampla
This species differs from L. tricuspis in lacking the vertical striations, the acuminate antapical horns, and the coarse "ornamentation". Doubt is expressed in the generic assignment because of uncertainties in the nature of the archeopyle in this species and in the genus. The archeopyle as seen in the holotype is perfectly clear and does not appear to be of accidental origin. Evitt (pers. comm.) has commented on the resemblance of the small folds, often observed on the test of these cysts, to growth lines such as those exhibited by Palaeoperidinium pyrophorum (Ehrenberg). Its affinities are unknown.