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Acanthaulax miocenica
Acanthaulax miocenica, Zevenboom and Santarelli in Zevenboom, 1995, p. 149, pl. 1, figs. 1-6.
Name not validly published: considered a manuscript name by the authors.
Holotype: Zevenboom, 1995, pl.1, figs.1-3; Manuscript holotype: Sample Gia 54a, EF (Q17/4). Plate I, 1-3; Manuscript paratype: Sample Gia, 54a EF (T34/3). Plate I, 4-6
Type locality: Monte Gibliscemi, Sicily, Italy.
Type stratum: Terrajecchia Formation.
Age: Tortonian-Messinian.
Occurrence: Italy (this study), The Netherlands (this study), Germany (Daniels et al., 1990), Norwegian Sea (Manum et al., 1989)
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Original description: [Zevenboom, 1995]:
Diagnosis:
A relatively large species of Acanthaulax characterized by a distinctly rugulate wall.
Description:
A species of Acanthaulax characterized by a distinctly rugulate periphragm. The endophragm is smooth. The periphragm gives rise to numerous short, simple spines, which are usually capitate and to low parasutural ridges, also covered with spines. On most specimens, the parasutural ridges are better developed on the dorsal side. The spines are generally proximally connected, resulting in the rugulate structure of the periphragm. On some specimens distinctive rows of more massive processes or coni around the archaeopyle margin have been observed.
The archaeopyle is precingular and formed by the loss of paraplate 3". Operculum free.
The parasutural ridges delineate a gonyaulacacean tabulation characteristic for the genus.
Dimensions:
Height: 55 (58) 60 µm; Width: 61 (70) 75 µm; Wall thickness: 1.5 - 2 µm; Spine: 2(4)7 µm. N=11.
Discussion:
Representatives of Acanthaulax are particularly known from Mesozoic deposits. Occurrences of representatives of the genus in younger deposits may hence be suspected to be due to reworking. However, specimens of Acanthaulax miocenica Zevenboom and Santarelli, have been found to dominate several studied intervals in sections in the Upper Miocene of Italy. Their abundance in these intervals is difficult to reconcile with reworking. The new species differs from all other Acanthaulax species by the usually proximally connected spines and by lacing an apical horn or protrusion.
Name not validly published: considered a manuscript name by the authors.
Holotype: Zevenboom, 1995, pl.1, figs.1-3; Manuscript holotype: Sample Gia 54a, EF (Q17/4). Plate I, 1-3; Manuscript paratype: Sample Gia, 54a EF (T34/3). Plate I, 4-6
Type locality: Monte Gibliscemi, Sicily, Italy.
Type stratum: Terrajecchia Formation.
Age: Tortonian-Messinian.
Occurrence: Italy (this study), The Netherlands (this study), Germany (Daniels et al., 1990), Norwegian Sea (Manum et al., 1989)
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Zevenboom, 1995]:
Diagnosis:
A relatively large species of Acanthaulax characterized by a distinctly rugulate wall.
Description:
A species of Acanthaulax characterized by a distinctly rugulate periphragm. The endophragm is smooth. The periphragm gives rise to numerous short, simple spines, which are usually capitate and to low parasutural ridges, also covered with spines. On most specimens, the parasutural ridges are better developed on the dorsal side. The spines are generally proximally connected, resulting in the rugulate structure of the periphragm. On some specimens distinctive rows of more massive processes or coni around the archaeopyle margin have been observed.
The archaeopyle is precingular and formed by the loss of paraplate 3". Operculum free.
The parasutural ridges delineate a gonyaulacacean tabulation characteristic for the genus.
Dimensions:
Height: 55 (58) 60 µm; Width: 61 (70) 75 µm; Wall thickness: 1.5 - 2 µm; Spine: 2(4)7 µm. N=11.
Discussion:
Representatives of Acanthaulax are particularly known from Mesozoic deposits. Occurrences of representatives of the genus in younger deposits may hence be suspected to be due to reworking. However, specimens of Acanthaulax miocenica Zevenboom and Santarelli, have been found to dominate several studied intervals in sections in the Upper Miocene of Italy. Their abundance in these intervals is difficult to reconcile with reworking. The new species differs from all other Acanthaulax species by the usually proximally connected spines and by lacing an apical horn or protrusion.