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Dapsilidinium warrenii
Dapsilidinium warrenii (Habib, 1976) Lentin and Williams, 1981
Holotype: Habib 1976, Pl. 2, fig. 6a-b
Locus typicus: DSDP site 105, western North Atlantic.
Stratum typicum: Druggidinium apicopaucicum Zone (Berriasian to Valanginian?)
Originally Polysphaeridium, subsequently (and now) Dapsilidinium.
Age: Berriasian-Aptian
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G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Dapsilidinium warrenii (Habib, 1976) Lentin and Williams, 1981, has a subcircular to elliptical outline. Numerous thin, hollow, distally open cylindrical processes extend outward perpendicularly from the periphragm, leaving a circular ring at the base. The processes number 60 to 68 and are nontabular. Periphragm microgranulate to minutely spinate. This species differs from D. laminaspinosum in having many more processes and in the processes being more slender. It differs from D. multispinosum in having open processes distally. In D. multispinosum the processes are distally closed, slightly recurved and with a spinate margin. Size: central body 23-25 µm, length of processes 9-15 µm.
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Description: Habib 1976, p. 383: Polysphaeridium warrenii
Chorate dinoflagellate cysts with subcircular to elliptical outline. Periblast composed of two layers, with periphragm and endophragm in contact. Numerous thin, hollow, distally open cylindrical processes extend outward perpendicularly from the periphragm, leaving a circular ring at the base. The processes number from 60 to 68 and have a nontabular arrangement. Cyst tabulation not expressed, except at the outline of the archeopyle, which suggests six precingular plates. Archeopyle apical, with simple free operculum (type A). Periphragm texture microgranulate to minutely spinate.
Maximum dimension of twenty-two measured specimens, exclusive of processes, ranges from 23 to 35
microns; length of processes from 9 to 15 microns.
Remarks: Habib 1976, p. 383
The numerous thin, parallel-sided processes of Polysphaeridium warrenii distinguish it from other species in that genus. It is similar to P. Iaminaspmosum Davey and Williams, but possesses many more processes. Also, the processes of P. Iaminaspinosum do not appear to be as thin.
P. warrenii is very similar to P. multlspinosum Davey, from the Barremian Speeton Clay of England (Davey, 1974). However, the processes in the latter species terminate distally with a closed, slightly recurved spinate margin (R. J. Davey, personal communication), whereas in P. warrenii the processes are open distally in most cases and do not recurve. The two species would otherwise be considered conspecific.
P. warrenii resembles Tanyosphaeridium Isocalamus (Deflandre and Cookson) in the nature and arrangement of the processes, and in the possession of an apical archeopyle. The two species appear to differ only in their overall shape, and, since there are examples of P. warrenii which are elongate lengthwise, they may be morphogenetically related.
The species is named after John S. Warren, dinoflagellate paleontologist, who first reported it from the Lower Cretaceous of California (Warren, 1967).
In the western North Atlantic, P. warrenii ranges from the upper half of the Biorbifera johnewingii Zone through the Oilgosphaeridium complex Zone, which corresponds in age with Berriasian or Valanginian to Barremian (or Aptian ?).
Holotype: Habib 1976, Pl. 2, fig. 6a-b
Locus typicus: DSDP site 105, western North Atlantic.
Stratum typicum: Druggidinium apicopaucicum Zone (Berriasian to Valanginian?)
Originally Polysphaeridium, subsequently (and now) Dapsilidinium.
Age: Berriasian-Aptian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Dapsilidinium warrenii (Habib, 1976) Lentin and Williams, 1981, has a subcircular to elliptical outline. Numerous thin, hollow, distally open cylindrical processes extend outward perpendicularly from the periphragm, leaving a circular ring at the base. The processes number 60 to 68 and are nontabular. Periphragm microgranulate to minutely spinate. This species differs from D. laminaspinosum in having many more processes and in the processes being more slender. It differs from D. multispinosum in having open processes distally. In D. multispinosum the processes are distally closed, slightly recurved and with a spinate margin. Size: central body 23-25 µm, length of processes 9-15 µm.
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Description: Habib 1976, p. 383: Polysphaeridium warrenii
Chorate dinoflagellate cysts with subcircular to elliptical outline. Periblast composed of two layers, with periphragm and endophragm in contact. Numerous thin, hollow, distally open cylindrical processes extend outward perpendicularly from the periphragm, leaving a circular ring at the base. The processes number from 60 to 68 and have a nontabular arrangement. Cyst tabulation not expressed, except at the outline of the archeopyle, which suggests six precingular plates. Archeopyle apical, with simple free operculum (type A). Periphragm texture microgranulate to minutely spinate.
Maximum dimension of twenty-two measured specimens, exclusive of processes, ranges from 23 to 35
microns; length of processes from 9 to 15 microns.
Remarks: Habib 1976, p. 383
The numerous thin, parallel-sided processes of Polysphaeridium warrenii distinguish it from other species in that genus. It is similar to P. Iaminaspmosum Davey and Williams, but possesses many more processes. Also, the processes of P. Iaminaspinosum do not appear to be as thin.
P. warrenii is very similar to P. multlspinosum Davey, from the Barremian Speeton Clay of England (Davey, 1974). However, the processes in the latter species terminate distally with a closed, slightly recurved spinate margin (R. J. Davey, personal communication), whereas in P. warrenii the processes are open distally in most cases and do not recurve. The two species would otherwise be considered conspecific.
P. warrenii resembles Tanyosphaeridium Isocalamus (Deflandre and Cookson) in the nature and arrangement of the processes, and in the possession of an apical archeopyle. The two species appear to differ only in their overall shape, and, since there are examples of P. warrenii which are elongate lengthwise, they may be morphogenetically related.
The species is named after John S. Warren, dinoflagellate paleontologist, who first reported it from the Lower Cretaceous of California (Warren, 1967).
In the western North Atlantic, P. warrenii ranges from the upper half of the Biorbifera johnewingii Zone through the Oilgosphaeridium complex Zone, which corresponds in age with Berriasian or Valanginian to Barremian (or Aptian ?).