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Liesbergia scarburghensis
Liesbergia scarburghensis (Sarjeant, 1964, nom. subst. pro Gonyaulax areolata Sarjeant, 1961 non Gonyaulax areolata Kofoid and Michener, 1911) Berger, 1986
Now Trichodinium scarburghense. Originally Gonyaulax areolata (an illegitimate species name), subsequently Gonyaulacysta scarburghensis, thirdly Acanthaulax scarburghensis, fourthly Liesbergia scarburghensis, fifthly (and now) Trichodinium scarburghense. See also Gonyaulacysta areolata (combination illegitimate) and Acanthaulax areolata (combination illegitimate).
Tax. sr. synonym of Acanthaulax senta Drugg, 1978, according to Berger, 1986, Jan du Chêne et al., 1986, Riding, 1987, Brenner, 1988, and Kunz, 1990.
Kunz, 1990, retained this species in Acanthaulax Sarjeant, 1968.
Holotype: Sarjeant, 1961, pl.13, fig.13, text-fig.5, Jan du Chêne et al., 1986, pl.3, fig.1-2
Locus typicus: Scarborough Castle Cliff, England
Stratum typicum: Late Callovian-Early Oxfordian
Original diagnosis: Sarjeant, 1961, p.95: Gonyaulax areolata
A species of fossil Gonyaulax with an ovoid theca having the tabulation ?", 1a, 6", 6""", ?1p, 1"""" and with a strong, tapering apical horn rounded at its extremity. The whole thecal surface except the longitudinal and transverse furrows is covered by low ridges forming an irregular reticulate patterning; the thecal wall is very thin but consists of two layers, the outer bearing the ridges. The boundaries of plates and the furrow margins bear low alveolate crests. The longitudinal furrow extends from apex to antapex; it is narrow, as the transverse furrow.
Original description: Sarjeant, 1961, p.96: Gonyaulax areolata
Theca yellowish. Tabulation not easily discerned and a composite text-figure therefore given. Apical tabulation obscure. An anterior intercalary plate clearly present, plus six pre-equatorial plates, of which the first (1") is reduced. Transverse furrow extends around theca in a strong laevo-rotatory spiral such that its two ends differ in antero-posterior position by approximately three times the furrow"s width. Six postequatorial plates certainly present; a posterior intercalary plate appears present but could not be definitely confirmed. No posterior ventral plates present, longitudinal furrow extending to polygonal antapical plate. Surface reticulation of ridges dense; fields delimited by these ridges always small, not regularly polygonal but varying considerably in relative size and shape. Reticulation extending on to apical horn but absent from furrows. Crests consist of linked processes (links sometimes broken) arising from sutures, their points of origin corresponding with junctions of ridges with sutures.
Dimensions: Holotype: Overall length 155 µm, length of horn 25 µm, overall breadth 125 µm; transverse furrow c. 10 µm wide, longitudinal furrow c. 5 µm wide. Range: overall length 120 - 170 µm, relative proportions being fairly constant.
Berger, 1986, p. 343: Because of the elements already discussed (notably the structure of the apical horn), the species Gonyaulax scarburghensis is put in the genus Liesbergia. On the other hand it is confirmed that Acanthaulax senta G. scarburghense (holotype reexamined by W. Wille) are synonymous. Consequently, the forms described as A. senta or G. scarburghensis in the literature must be considered now as Liesbergia scarburghensis.
Now Trichodinium scarburghense. Originally Gonyaulax areolata (an illegitimate species name), subsequently Gonyaulacysta scarburghensis, thirdly Acanthaulax scarburghensis, fourthly Liesbergia scarburghensis, fifthly (and now) Trichodinium scarburghense. See also Gonyaulacysta areolata (combination illegitimate) and Acanthaulax areolata (combination illegitimate).
Tax. sr. synonym of Acanthaulax senta Drugg, 1978, according to Berger, 1986, Jan du Chêne et al., 1986, Riding, 1987, Brenner, 1988, and Kunz, 1990.
Kunz, 1990, retained this species in Acanthaulax Sarjeant, 1968.
Holotype: Sarjeant, 1961, pl.13, fig.13, text-fig.5, Jan du Chêne et al., 1986, pl.3, fig.1-2
Locus typicus: Scarborough Castle Cliff, England
Stratum typicum: Late Callovian-Early Oxfordian
Original diagnosis: Sarjeant, 1961, p.95: Gonyaulax areolata
A species of fossil Gonyaulax with an ovoid theca having the tabulation ?", 1a, 6", 6""", ?1p, 1"""" and with a strong, tapering apical horn rounded at its extremity. The whole thecal surface except the longitudinal and transverse furrows is covered by low ridges forming an irregular reticulate patterning; the thecal wall is very thin but consists of two layers, the outer bearing the ridges. The boundaries of plates and the furrow margins bear low alveolate crests. The longitudinal furrow extends from apex to antapex; it is narrow, as the transverse furrow.
Original description: Sarjeant, 1961, p.96: Gonyaulax areolata
Theca yellowish. Tabulation not easily discerned and a composite text-figure therefore given. Apical tabulation obscure. An anterior intercalary plate clearly present, plus six pre-equatorial plates, of which the first (1") is reduced. Transverse furrow extends around theca in a strong laevo-rotatory spiral such that its two ends differ in antero-posterior position by approximately three times the furrow"s width. Six postequatorial plates certainly present; a posterior intercalary plate appears present but could not be definitely confirmed. No posterior ventral plates present, longitudinal furrow extending to polygonal antapical plate. Surface reticulation of ridges dense; fields delimited by these ridges always small, not regularly polygonal but varying considerably in relative size and shape. Reticulation extending on to apical horn but absent from furrows. Crests consist of linked processes (links sometimes broken) arising from sutures, their points of origin corresponding with junctions of ridges with sutures.
Dimensions: Holotype: Overall length 155 µm, length of horn 25 µm, overall breadth 125 µm; transverse furrow c. 10 µm wide, longitudinal furrow c. 5 µm wide. Range: overall length 120 - 170 µm, relative proportions being fairly constant.
Berger, 1986, p. 343: Because of the elements already discussed (notably the structure of the apical horn), the species Gonyaulax scarburghensis is put in the genus Liesbergia. On the other hand it is confirmed that Acanthaulax senta G. scarburghense (holotype reexamined by W. Wille) are synonymous. Consequently, the forms described as A. senta or G. scarburghensis in the literature must be considered now as Liesbergia scarburghensis.