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Vozzhennikovia elegantula
Vozzhennikovia? elegantula Williams, 1978
Now Selenopemphix. Originally Vozzhennikovia?, subsequently (and now) Selenopemphix.
Williams, 1978, questionably included this species in Vozzhennikovia.
Holotype: Williams, 1978, pl.7, fig.8
Age: Middle Eocene
Original description (Williams, G.L., 1978):
?Vozzhennikovia elegantula sp. nov. (Plate 7, Figures 7, 9)
Diagnosis: The pericyst ambitus is ovoidal to pentagonal, widest in precingular region. Apex occasionally rounded, more commonly produced into a short apical horn which distally may be acuminate or oblate. Antapex flattened or with slight asymmetry, there being a weak left antapical lobe. Epipericyst and hypopericyst more or less equal in size. Lengthibreadth ratio about 1. Compression very slight. An endocyst has not been observed. Periphragm laevigate with parasutural processes which are simple, slender, distally oblate or bulbous. The processes may be isolated or united proximally by a membrane. The paratabulation is presumably peridinioid since there is a hexa 2a intercalary paraplate. Pericingulum helicoidal, heptapentapartite with parasutural processes. Perisulcus indented, largely restricted to the hypocyst and widening antapically. Archeopyle hexa, intercalary, resulting from the partial or complete detachment of the second anterior intercalary paraplate 2a. Operculum often remains attached along parasuture H4.
Dimensions: Pericyst length 50-52 µm, breadth 45-56 µm. Processes, length 2-10 µm. In apical view lateral width 45-50 µm. Number of specimens measured, 6.
Holotype: GSC No. 47910, P8182-O1. 10.2 × 101.7. Pericyst length 51 µm, breadth 56 µm. Process length 2-7 µm. Middle Eocene, Site 370.
Description: ?Vozzhennikovia elegantula has a distinctly peridinioid ambitus, but lacks the prominent antapical horns which characterize several peridinioid genera. The parasutural processes are hollow throughout or for half to two-thirds of their length, terminating in a slender solid tip. The cingular processes tend to be shorter than the others. Delineation of the paratabulation is difficult when the processes are not united proximally. The archeopyle is hexa with the operculum often remaining attached proximally.
Remarks: The genus Vozzhennikovia was erected by Lentin and Williams (1976) to include peridinioid taxa with processes which are nontabular. Six species were included in the genus Vozzhennikovia by these authors. Only two, IV. extensa (Stover) Lentin and Williams and IV. filigrana (Benedek) Lentin and Williams, are known to possess a broad hexa 2a archeopyle, but both have nontabular processes. V. elegantula is questionably placed in Vozzhennikovia because of its parasutural processes. It cannot be included in the genus Wilsonidium Lentin and Williams which has parasutural ornamentation because of the possession by that genus of a quadra 2a archeopyle. The only other comparable genus, Sumatradinium Lentin and Williams, lacks an apical horn. The coordinates given are those for a Zeiss Photomicroscope II. The vertical reading precedes the horizontal. The repository for all type material is the Geological Survey of Canada, Ottawa.
Now Selenopemphix. Originally Vozzhennikovia?, subsequently (and now) Selenopemphix.
Williams, 1978, questionably included this species in Vozzhennikovia.
Holotype: Williams, 1978, pl.7, fig.8
Age: Middle Eocene
Original description (Williams, G.L., 1978):
?Vozzhennikovia elegantula sp. nov. (Plate 7, Figures 7, 9)
Diagnosis: The pericyst ambitus is ovoidal to pentagonal, widest in precingular region. Apex occasionally rounded, more commonly produced into a short apical horn which distally may be acuminate or oblate. Antapex flattened or with slight asymmetry, there being a weak left antapical lobe. Epipericyst and hypopericyst more or less equal in size. Lengthibreadth ratio about 1. Compression very slight. An endocyst has not been observed. Periphragm laevigate with parasutural processes which are simple, slender, distally oblate or bulbous. The processes may be isolated or united proximally by a membrane. The paratabulation is presumably peridinioid since there is a hexa 2a intercalary paraplate. Pericingulum helicoidal, heptapentapartite with parasutural processes. Perisulcus indented, largely restricted to the hypocyst and widening antapically. Archeopyle hexa, intercalary, resulting from the partial or complete detachment of the second anterior intercalary paraplate 2a. Operculum often remains attached along parasuture H4.
Dimensions: Pericyst length 50-52 µm, breadth 45-56 µm. Processes, length 2-10 µm. In apical view lateral width 45-50 µm. Number of specimens measured, 6.
Holotype: GSC No. 47910, P8182-O1. 10.2 × 101.7. Pericyst length 51 µm, breadth 56 µm. Process length 2-7 µm. Middle Eocene, Site 370.
Description: ?Vozzhennikovia elegantula has a distinctly peridinioid ambitus, but lacks the prominent antapical horns which characterize several peridinioid genera. The parasutural processes are hollow throughout or for half to two-thirds of their length, terminating in a slender solid tip. The cingular processes tend to be shorter than the others. Delineation of the paratabulation is difficult when the processes are not united proximally. The archeopyle is hexa with the operculum often remaining attached proximally.
Remarks: The genus Vozzhennikovia was erected by Lentin and Williams (1976) to include peridinioid taxa with processes which are nontabular. Six species were included in the genus Vozzhennikovia by these authors. Only two, IV. extensa (Stover) Lentin and Williams and IV. filigrana (Benedek) Lentin and Williams, are known to possess a broad hexa 2a archeopyle, but both have nontabular processes. V. elegantula is questionably placed in Vozzhennikovia because of its parasutural processes. It cannot be included in the genus Wilsonidium Lentin and Williams which has parasutural ornamentation because of the possession by that genus of a quadra 2a archeopyle. The only other comparable genus, Sumatradinium Lentin and Williams, lacks an apical horn. The coordinates given are those for a Zeiss Photomicroscope II. The vertical reading precedes the horizontal. The repository for all type material is the Geological Survey of Canada, Ottawa.