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Hystrichodinium voigtii

From Fensome et al., 2019:
Hystrichodinium voigtii (Alberti, 1961, p.33, pl.8, figs.1–5) Davey, 1974, p.54. Emendation: Sarjeant, 1966b, p.142, as Heliodinium voigtii. Holotype: Alberti, 1961, pl.8, fig.2. Originally Heliodinium, subsequently (and now) Hystrichodinium. Backhouse (1988, p.92) considered Hystrichodinium oligacanthum to be the possible taxonomic senior synonym of this species. Age: Barremian–early Aptian.

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Locus typicus: Haverlahwiese, Germany
Stratum typicum: Barremian-Early Aptian
Translation Alberti, 1961: LPP

Original diagnosis: Alberti, 1961, p.33: Heliodinium voigtii
(same as for genus) Shell polyedrical, partly rounded, sometimes ovoidal. Dorsoventral flattened. Epitheka slightly larger than Hypocyst or both of equal size. Tranverse furrow laevorotatory, slightly indented. Shell tabulate. Pre- and postcingular plates trapezoidal. Probably 6 preequatorial plates. Longitudinal furrow system present. On plate boundaries crests from which dagger-like processes arise.

Original description: Alberti, 1961, p.33
Sutures from which +/- long, basal widened processes arise are characteristic for H. voigtii. Six cingular plates are presumed, number of pre- and postcingular plates unknown. Postcingular plates trapezoidal. Longitudinal furrow relatively narrow. Membrane delicate and hyaline. Pylome trapezoidal.
Dimensions: Length of holotype: 48 µm, breadth 38 µm, length of processes 16-22 µm. Range: length 49-60 µm, breadth 40-56 µm, length of processes 19-36 µm.

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Supplemental description: Davey, 1974, p.175
The shell is ovoidal to subpolygonal. The periphragm is smooth or slightly granular, and forms sutural crests and ribbon-like processes. The former are variably developed, may occasionally be absent, but when present give rise to long, flexuous processes along their length. When the crests are absent the processes arise directly from the shell surface. The processes are not confined to the plate boundaries and may be distributed at random over the shell surface. The processes are thin-walled, typically simple and occasionally terminate with bifurcate or trifurcate extremities. The cingulum (4-5 µm wide) is always delimited by low crests and is strongly helicoid. A precingular archaeopyle, formed by the loss of plate 3", is typically present. One detached operculum has been located and bears five processes.
Dimensions: Range of observed specimens: shell length 40 (49.6) 62 µm, width 40 (48.4) 58 µm, length of processes 27 (35.6) 48 µm. Number of specimens measured, 11.

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Emended description Sarjeant, 1966b:

Heliodinium voigti Alberti
Pl. 16, fig. 2; Text-fig. 36
1961. Heliodinium voigti Alberti: 33, pl. 8, figs. 1-5.

EMENDED DIAGNOSIS. A Heliodinium having a subpolygonal shell, epitract almost conical and hypotract in form of truncated cone. Tabulation
?3’, ?oa, 6'’, ?oc, 6”’, ?op, 1"" ; sutures generally marked only by low ridges, but cingulum and antapex bordered by low crests. Processes dagger-like, frequently highly folded, length less than half shell length ; distal ends of processes typically simple, rarely bifurcate or trifurcate. Shell surface smooth or only minutely granular.

DIMENSIONS.
Holotype: shell length 48u, breadth 38u, length of processes 16-22u. Range of German specimens: shell length 48-60u, breadth 38—56u, length of processes 16-36u. Specimen here figured : overall length c.125y, breadth c.105u : shell length 62u, breadth 45u.

DESCRIPTION. This species occurs in low numbers in the assemblages from the Chalk at 840 and 810 feet depth (basal Cenomanian) in the Fetcham Mill bore. Although a number of specimens were available for study, the majority proved unsuitable as a result of distortion or unfortunate orientation : the figured specimen was the only one capable of full study. It was thus not possible to confirm details of the apical structure.
Plate 1’ is elongate and corresponds to the apical prolongation of the sulcus. At least two other apical plates appear to be present : no anterior intercalary plate could be distinguished. Six precingular and six postcingular plates are present ; no posterior intercalary plate was distinguished. The antapex is occupied by a single plate.
The cingulum forms a strong laevorotatory spiral whose two ends differ in anteroposterior position by three times its width. There appears to be no separation into cingular plates. The sulcus is narrow and extends to the antapex.
The shell surface appears devoid of ornamentation. The processes are flattened and very flexible, generally simple—one process in the figured specimen is bifurcate, one trifurcate.
Plate 3” is generally lost in pylome formation.

REMARKS. The diagnosis of this species is emended to incorporate new observations. Alberti (1961 : 33) noted the presence of an archaeopyle in one specimen, but did not refer to this in the diagnosis.
The stratigraphic range of the German specimens is Lower Barremian to ?Lower Aptian : the English occurrence thus represents a vertical extension of this range.

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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.

Hystrichodinium voigtii (Alberti, 1961) Davey, 1974, emend. Sarjeant, 1966b. According to Sarjeant (1966b), this species has dagger-like processes, frequently highly folded, length less than half body diameter. Sutures generally marked by low ridges, but cingulum and antapex bordered by low crests. Distal ends of processes typically simple. Size: central body length 48-60 µm, width 38-56 µm, process length 16-36 µm.
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