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Artemisiocysta cladodichotoma
Artemisiocysta cladodichotoma, Benedek, 1972
Holotype: Benedek, 1972, pl.12, fig.8a-b
Locus typicus: Toenisberg, Lower Rhine Area, Germany
Stratum typicum: Middle-Late Oligocene
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Original description: [Benedek, 1972, p.49]: (Translation: LPP)
Diagnosis:
An elongate-polygonal capsule. Arising from the untabulated suface and extending from the interior are hollow, broadly based, distally dichotomously ended processes that influence the shape of the capsule. Processes end in short spines. A pylome is unknown.
Description:
Irregular, nontabular capsule, with 20 hollow, stoudy, distally multifurcate processes. Process bases widened. Process distribution irregular, not indicating a tabulation. Smaller processes (2-3 µm), situated near the bases of larger processes, may be reduced to small hooks.
Dimensions:
capsule c. 50-55 µm, process length 10-12 µm (5 specimens measured).
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Remarks:
Heilmann-Clausen in Heilmann-Clausen and Costa, 1989, p. 464; pl.8,figs.5,7-9:
The specimens recovered are all brown-pigmented. The archaeopyle which has never been described, was not identified. Nevertheless, Artemisiocysta is almost certainly a protoperidiniacean genus with affinity to Gerlachidinium Benedek and Sarjeant, 1981.
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Poulsen et al., 1996, p. 282:
As with earlier records, we have not observed an archeopyle. Lacking proven dinoflagellate characters, Fensome et al. (1993) classified this cyst as an acritarch. However, many characters strongly suggest that it is a protoperidinoid cyst. The process type and the pentagonal outline of many specimens are reminiscent of the genus Trinovantedinium, and the grayish brown color of the phragm is also protoperidinoid.
Distribution:
The species occurs consistently below the unconformity at Site 908. Above the unconformity, Artemisiocysta sp. is recorded as abundant in a single sample, but this is a different species having more and delicate processes. Benedek and Muller (1974) showed A. cladodichotoma to be restricted to the Chattian when they established the nannoplankton control for the Tonisberg borehole, the type locality of the species. However, Benedek (1972) had in his original paper recorded the species also from Rupelian sediments, and the interval with its oldest record was actually retained in the Rupelian by Benedek and Muller (1974), who apparently missed it from the Rupelian in their range chart. Therefore, our Rupelian assignment of the section at Site 908 containing A. cladodichotoma is not in conflict with Benedek"s (1972) record of it. No reliable last occurrence datum for the species is yet recorded
Holotype: Benedek, 1972, pl.12, fig.8a-b
Locus typicus: Toenisberg, Lower Rhine Area, Germany
Stratum typicum: Middle-Late Oligocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Benedek, 1972, p.49]: (Translation: LPP)
Diagnosis:
An elongate-polygonal capsule. Arising from the untabulated suface and extending from the interior are hollow, broadly based, distally dichotomously ended processes that influence the shape of the capsule. Processes end in short spines. A pylome is unknown.
Description:
Irregular, nontabular capsule, with 20 hollow, stoudy, distally multifurcate processes. Process bases widened. Process distribution irregular, not indicating a tabulation. Smaller processes (2-3 µm), situated near the bases of larger processes, may be reduced to small hooks.
Dimensions:
capsule c. 50-55 µm, process length 10-12 µm (5 specimens measured).
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Remarks:
Heilmann-Clausen in Heilmann-Clausen and Costa, 1989, p. 464; pl.8,figs.5,7-9:
The specimens recovered are all brown-pigmented. The archaeopyle which has never been described, was not identified. Nevertheless, Artemisiocysta is almost certainly a protoperidiniacean genus with affinity to Gerlachidinium Benedek and Sarjeant, 1981.
----------------------------------------
Poulsen et al., 1996, p. 282:
As with earlier records, we have not observed an archeopyle. Lacking proven dinoflagellate characters, Fensome et al. (1993) classified this cyst as an acritarch. However, many characters strongly suggest that it is a protoperidinoid cyst. The process type and the pentagonal outline of many specimens are reminiscent of the genus Trinovantedinium, and the grayish brown color of the phragm is also protoperidinoid.
Distribution:
The species occurs consistently below the unconformity at Site 908. Above the unconformity, Artemisiocysta sp. is recorded as abundant in a single sample, but this is a different species having more and delicate processes. Benedek and Muller (1974) showed A. cladodichotoma to be restricted to the Chattian when they established the nannoplankton control for the Tonisberg borehole, the type locality of the species. However, Benedek (1972) had in his original paper recorded the species also from Rupelian sediments, and the interval with its oldest record was actually retained in the Rupelian by Benedek and Muller (1974), who apparently missed it from the Rupelian in their range chart. Therefore, our Rupelian assignment of the section at Site 908 containing A. cladodichotoma is not in conflict with Benedek"s (1972) record of it. No reliable last occurrence datum for the species is yet recorded