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Tubotuberella missilis
Tubotuerella missilis Stover and Helby, 1987
Holotype: Stover and Helby. 1987, fig.25A-G
Locus typicus: Carnarvon Basin, Australia
Stratum typicum: Kimmeridgian
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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.
Tubotuberella missilis Stover and Helby, 1987a, differs from other species of the genus in possessing perforate-fenestrate septa. It is an imposing beast. Size: length 180-270 µm, width 64-90 µm, septa 3-12 µm high.
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Original description: Stover and Helby, 1987, p.124-125
Cysts proximate, bicavate, longitudinally elongate, with a prominent apical horn and a subcylindrical antapical extension, both formed by the periphragm. Antapical extension open posteriorly. Outline of endocyst fusiform and the apical end narrower and slightly shorter than the antapical one. From the ends of the endocyst to those of the pericyst, epipericoel longer and narrower than hypopericoel; where pericoels not developed wall layers virtually indistinguishable. Endophragm smooth. Periphragm faintly ornamented, with scattered granules. Parasutural septa may be perforate or fenestrate. Septa about 1.5µm wide, from 3-12µm high, height of some longitudinal septa increases towards the poles. Perforations circular, elliptical to irregularly rounded and their maximum dimension (usually height) variable from about 1-9µm. most less than 4µm. Paratabulation, as expressed by the perforate-fenestrate parasutural features, X', 5'', 4-6c, 5''', 1p?, 1'''' (Fig.24).
Paracingulum nearer antapex than apex, expressed by 2, subparallel, transverse, generally low septa, offset markedly and subdivided. Only posterior part of parasulcus delimited by parasutural features.
Archeopyle precingular, type P, 3 " only, operculum free.
Specimens 180-270 µm long and 64-90 µm wide; 10 specimens measured of which 7 are more than 240 µm.
Comment: The shape of the slender, prominent apical horn on T. missilis resembles that of Conyaulacysta jurassica (Deflandre) Norris & Sarjeant 1965 (see Stover & Evitt, 1978, p.276). On some specimens of T. missilis a small, more or less circular depression (pore?) occurs ventrally on the right side of the horn (Fig.24A, arrow) and the horn's tip is thickened and evidently open. Indistinct traces of 2 preapical paraplates may be present on the anterior right dorsal surface. Also discernible on the dorsal surface is a longitudinal thickening (Fig.24B, arrow), which we interpret as the 2'/3' boundary. Other thickenings are present on the posterior of the horn, but it is difficult to trace them and to separate those which may be parasutural from those caused by compression. Thus, we were unable to determine the configuration of the apical series. Paratabulation is reduced on the midventral area so that the cysts lack indications of 6'', 1''' and the sulcal paraplates. The right septum of 1'' is consistently incomplete. Parasutural features on the dorsal surface tend to be slightly higher than those on the ventral surface. Moreover, the difference in height at the extremities of individual longitudinal septa may be appreciable, especially for those on the hypocyst. At the antapex, the terminations of the perforate-fenestrate septa may form short, spine-like projections which are directed posteriorly.
Affinities:
Stover and Evitt, 1987, p. 127: Tubotuberella missilis differs from other species of the genus in possessing perforate-fenestrate septa. The parasutural features are low, smooth ridges on T. dangeardii (Sarjeant) Stover & Evitt 1978, T. egemenii (Gitmez) Stover & Evitt 1978, T. rhombiformis Vozzhennikova 1967 and T. whatleyi (Sarjeant) Stover & Evitt 1978. Alternatively, ridges with denticulate to spinose crests occur on T. dentata Raynaud 1978, T. eisenackii (Deflandre) Stover & Evitt 1978, T. sphaerocephalis Vozzhennikova 1967. Ridges are absent from T. apatela (Cookson & Eisenack) Ioannides et al. 1977.
Holotype: Stover and Helby. 1987, fig.25A-G
Locus typicus: Carnarvon Basin, Australia
Stratum typicum: Kimmeridgian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Tubotuberella missilis Stover and Helby, 1987a, differs from other species of the genus in possessing perforate-fenestrate septa. It is an imposing beast. Size: length 180-270 µm, width 64-90 µm, septa 3-12 µm high.
--------------------------------------------------
Original description: Stover and Helby, 1987, p.124-125
Cysts proximate, bicavate, longitudinally elongate, with a prominent apical horn and a subcylindrical antapical extension, both formed by the periphragm. Antapical extension open posteriorly. Outline of endocyst fusiform and the apical end narrower and slightly shorter than the antapical one. From the ends of the endocyst to those of the pericyst, epipericoel longer and narrower than hypopericoel; where pericoels not developed wall layers virtually indistinguishable. Endophragm smooth. Periphragm faintly ornamented, with scattered granules. Parasutural septa may be perforate or fenestrate. Septa about 1.5µm wide, from 3-12µm high, height of some longitudinal septa increases towards the poles. Perforations circular, elliptical to irregularly rounded and their maximum dimension (usually height) variable from about 1-9µm. most less than 4µm. Paratabulation, as expressed by the perforate-fenestrate parasutural features, X', 5'', 4-6c, 5''', 1p?, 1'''' (Fig.24).
Paracingulum nearer antapex than apex, expressed by 2, subparallel, transverse, generally low septa, offset markedly and subdivided. Only posterior part of parasulcus delimited by parasutural features.
Archeopyle precingular, type P, 3 " only, operculum free.
Specimens 180-270 µm long and 64-90 µm wide; 10 specimens measured of which 7 are more than 240 µm.
Comment: The shape of the slender, prominent apical horn on T. missilis resembles that of Conyaulacysta jurassica (Deflandre) Norris & Sarjeant 1965 (see Stover & Evitt, 1978, p.276). On some specimens of T. missilis a small, more or less circular depression (pore?) occurs ventrally on the right side of the horn (Fig.24A, arrow) and the horn's tip is thickened and evidently open. Indistinct traces of 2 preapical paraplates may be present on the anterior right dorsal surface. Also discernible on the dorsal surface is a longitudinal thickening (Fig.24B, arrow), which we interpret as the 2'/3' boundary. Other thickenings are present on the posterior of the horn, but it is difficult to trace them and to separate those which may be parasutural from those caused by compression. Thus, we were unable to determine the configuration of the apical series. Paratabulation is reduced on the midventral area so that the cysts lack indications of 6'', 1''' and the sulcal paraplates. The right septum of 1'' is consistently incomplete. Parasutural features on the dorsal surface tend to be slightly higher than those on the ventral surface. Moreover, the difference in height at the extremities of individual longitudinal septa may be appreciable, especially for those on the hypocyst. At the antapex, the terminations of the perforate-fenestrate septa may form short, spine-like projections which are directed posteriorly.
Affinities:
Stover and Evitt, 1987, p. 127: Tubotuberella missilis differs from other species of the genus in possessing perforate-fenestrate septa. The parasutural features are low, smooth ridges on T. dangeardii (Sarjeant) Stover & Evitt 1978, T. egemenii (Gitmez) Stover & Evitt 1978, T. rhombiformis Vozzhennikova 1967 and T. whatleyi (Sarjeant) Stover & Evitt 1978. Alternatively, ridges with denticulate to spinose crests occur on T. dentata Raynaud 1978, T. eisenackii (Deflandre) Stover & Evitt 1978, T. sphaerocephalis Vozzhennikova 1967. Ridges are absent from T. apatela (Cookson & Eisenack) Ioannides et al. 1977.