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Achomosphaera quadrata
From Fensome et al., 2019:
Achomosphaera quadrata, Antolinez-Delgado and Oboh-Ikuenobe, 2007, p.54–55, pl.1, fig.6.
Holotype: Antolinez-Delgado and Oboh-Ikuenobe, 2007, pl.1, fig.6.
Age: Paleocene–?earliest Eocene.
Stratigraphic range: Achomosphaera quadrata sp. nov. was observed in the Alo-1 well from 73 m to 548.6 m
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Original description: [Antolinez-Delgado and Oboh-Ikuenobe, 2007]:
Diagnosis:
A species of Achomosphaera with tubiform gonal processes having trifurcate to quadrifurcate terminations and commonly square distal outlines.
Description:
Proximochorate dinoflagellate cysts, spherical to subspherical body, slightly fibrous periphragm closely appressed to the endophragm except at the bases of processes; areas between processes smooth. Processes are gonal, tubiform, hollow, expanded distally into buccinate structures with trifurcate or more commonly quadrifurcate terminations. On some processes the distal terminations have entire margins and square outlines, whereas on others the distal terminations are irregular. Occasional adjacent processes are connected along their bases by thin lines of periphragm.
Archeopyle is precingular, type P3'', operculum free.
Dimensions:
Length 45–70 µm; width 38–60 µm; height of processes 10–15 µm (6 specimens measured).
Holotype: length 60 µm; width 58 µm; height of processes 15 µm.
Affinities/Comparison:
Achomosphaera quadrata sp. nov. is distinguished from other species because of its distinctive quadrifurcate gonal processes with commonly square distal outlines. Achomosphaera alcicornu (Eisenack 1954) Davey & Williams 1966 differs in having trifurcate processes with typically bifid distal terminations. Achomosphaera andalousiensis Jan du Chêne 1977 has gonal processes that are typically trifurcate, but which can also be bifurcate or quadrifurcate. However, each final furcation in Achomosphaera andalousiensis is connected to the nearest ones by narrow trabeculae forming a closed polygonal reticulum with a spine at each angle. Processes in Achomosphaera crassipellis (Deflandre & Cookson 1955) Stover & Evitt 1978 are gonal with typically trifurcate rather than quadrifurcate distal ends.
Achomosphaera quadrata, Antolinez-Delgado and Oboh-Ikuenobe, 2007, p.54–55, pl.1, fig.6.
Holotype: Antolinez-Delgado and Oboh-Ikuenobe, 2007, pl.1, fig.6.
Age: Paleocene–?earliest Eocene.
Stratigraphic range: Achomosphaera quadrata sp. nov. was observed in the Alo-1 well from 73 m to 548.6 m
---------------------------------------------------------------------------------------------------
Original description: [Antolinez-Delgado and Oboh-Ikuenobe, 2007]:
Diagnosis:
A species of Achomosphaera with tubiform gonal processes having trifurcate to quadrifurcate terminations and commonly square distal outlines.
Description:
Proximochorate dinoflagellate cysts, spherical to subspherical body, slightly fibrous periphragm closely appressed to the endophragm except at the bases of processes; areas between processes smooth. Processes are gonal, tubiform, hollow, expanded distally into buccinate structures with trifurcate or more commonly quadrifurcate terminations. On some processes the distal terminations have entire margins and square outlines, whereas on others the distal terminations are irregular. Occasional adjacent processes are connected along their bases by thin lines of periphragm.
Archeopyle is precingular, type P3'', operculum free.
Dimensions:
Length 45–70 µm; width 38–60 µm; height of processes 10–15 µm (6 specimens measured).
Holotype: length 60 µm; width 58 µm; height of processes 15 µm.
Affinities/Comparison:
Achomosphaera quadrata sp. nov. is distinguished from other species because of its distinctive quadrifurcate gonal processes with commonly square distal outlines. Achomosphaera alcicornu (Eisenack 1954) Davey & Williams 1966 differs in having trifurcate processes with typically bifid distal terminations. Achomosphaera andalousiensis Jan du Chêne 1977 has gonal processes that are typically trifurcate, but which can also be bifurcate or quadrifurcate. However, each final furcation in Achomosphaera andalousiensis is connected to the nearest ones by narrow trabeculae forming a closed polygonal reticulum with a spine at each angle. Processes in Achomosphaera crassipellis (Deflandre & Cookson 1955) Stover & Evitt 1978 are gonal with typically trifurcate rather than quadrifurcate distal ends.