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Selenopemphix dionaeacysta
Selenopemphix dionaeacysta Head et al., 1989
Taxonomic junior synonym: Selenopemphix harpeza, according to Head (1993, p.36).
Holotype. Head et al. 1989b: Plate 1, Figure 7
Locus typicus: ODP Leg 105, Site 646. Labrador Sea
Stratum typicum: Late Miocene
Age: Late Miocene-early Pliocene
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Selenopemphix dionaeacysta Head et al., 1989b. Diagnosis according to Head et al. (1989b, p.459-460), cysts small, polar compressed, and with a suboval to reniform outline, often with an incised parasulcus. Autophragm pale brown to medium brown and with a smooth wall surface. Paracingular folds bear processes that may have acuminate, blunt or slightly expanded or bifid tips, and some of which may be simply branched. Processes are closed distally, are hollow or partially solid, and are proximally open to the cyst cavity. Archeopyle is a large rounded hexa-intercalary and is strongly offset relative to the dorsoventral midline. Size: overall excluding processes 23-42 µm, process length 4-8 µm.
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Original diagnosis: Head et al. 1989b, p. 459-460
Cysts small, polar compressed, and with a suboval to teniform outline, often with an incised panasulcus. Autophragm pale brown to medium brown and with a smooth wall surface. Paracingular folds bear processes that may have acuminate, blunt or slightly expanded or bifid tips, and some of which may be simply branched. Processes are closed distally, are hollow or partially solid, and are proximally open to the cyst cavity Archeopyle is a large rounded hexa-intercalary and is strongly offset relative to the dorsoventral midline.
Dimensions. Holotype: maximum length of body (excluding processes), 38 µm. Range in maximum diameter (excluding processes), 23(33.8)42 µm. Process length around 4 to 8 µm. Seventeen specimens were measured.
Original description. The paracingular processes show considerable variability in morphology and number, and various types are found on the same cyst. Spines may be loosely clustered on indistinct lobations of the paracingular folds, (reflecting tabulation), although typically spines are fairly regularly distributed along the folds. The archeopyle was rarely observed due to the adherence of the operculum.
Discussion. This species is distinguished from others in the genus by its small size and nature of the paracingular processes. It has previously been recorded from the upper lower to upper Miocene of the Gulf of Mexico (Duffield and Stein, 1986), and from the middle to uppermost Miocene of Northwest Italy (Powell, 1986).
Remarks Head et al., 1989, p.439:
This species has previously been recorded from the upper lower to upper Miocene of the Gulf of Mexico (as Selenopemphix sp. A and sp. B in Duffield and Stein, 1986), from the upper Miocene (Discoaster berggreni nannofossil Zone) of DSDP Site 502, Carribean Sea (as Selenopemphix sp. B of Duffield and Stein, 1986; J.H. Wrenn, pers. comm. to M.J.H., 1986) and from the middle to uppermost Miocene of northwest Italy (as Xandarodinium? sp. cf. X. variabile in Powell, 1986).
Taxonomic junior synonym: Selenopemphix harpeza, according to Head (1993, p.36).
Holotype. Head et al. 1989b: Plate 1, Figure 7
Locus typicus: ODP Leg 105, Site 646. Labrador Sea
Stratum typicum: Late Miocene
Age: Late Miocene-early Pliocene
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP
Selenopemphix dionaeacysta Head et al., 1989b. Diagnosis according to Head et al. (1989b, p.459-460), cysts small, polar compressed, and with a suboval to reniform outline, often with an incised parasulcus. Autophragm pale brown to medium brown and with a smooth wall surface. Paracingular folds bear processes that may have acuminate, blunt or slightly expanded or bifid tips, and some of which may be simply branched. Processes are closed distally, are hollow or partially solid, and are proximally open to the cyst cavity. Archeopyle is a large rounded hexa-intercalary and is strongly offset relative to the dorsoventral midline. Size: overall excluding processes 23-42 µm, process length 4-8 µm.
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Original diagnosis: Head et al. 1989b, p. 459-460
Cysts small, polar compressed, and with a suboval to teniform outline, often with an incised panasulcus. Autophragm pale brown to medium brown and with a smooth wall surface. Paracingular folds bear processes that may have acuminate, blunt or slightly expanded or bifid tips, and some of which may be simply branched. Processes are closed distally, are hollow or partially solid, and are proximally open to the cyst cavity Archeopyle is a large rounded hexa-intercalary and is strongly offset relative to the dorsoventral midline.
Dimensions. Holotype: maximum length of body (excluding processes), 38 µm. Range in maximum diameter (excluding processes), 23(33.8)42 µm. Process length around 4 to 8 µm. Seventeen specimens were measured.
Original description. The paracingular processes show considerable variability in morphology and number, and various types are found on the same cyst. Spines may be loosely clustered on indistinct lobations of the paracingular folds, (reflecting tabulation), although typically spines are fairly regularly distributed along the folds. The archeopyle was rarely observed due to the adherence of the operculum.
Discussion. This species is distinguished from others in the genus by its small size and nature of the paracingular processes. It has previously been recorded from the upper lower to upper Miocene of the Gulf of Mexico (Duffield and Stein, 1986), and from the middle to uppermost Miocene of Northwest Italy (Powell, 1986).
Remarks Head et al., 1989, p.439:
This species has previously been recorded from the upper lower to upper Miocene of the Gulf of Mexico (as Selenopemphix sp. A and sp. B in Duffield and Stein, 1986), from the upper Miocene (Discoaster berggreni nannofossil Zone) of DSDP Site 502, Carribean Sea (as Selenopemphix sp. B of Duffield and Stein, 1986; J.H. Wrenn, pers. comm. to M.J.H., 1986) and from the middle to uppermost Miocene of northwest Italy (as Xandarodinium? sp. cf. X. variabile in Powell, 1986).