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Phoberocysta lowryi
Phoberocysta lowryi Backhouse, 1987
Tax. jr. synonym of Muderongia testudinaria Burger, 1980, according to Monteil, 1991.
Holotype: Backhouse, 1987, fig. 12C-D
Locus typicus: Perth Basin, Australia
Stratum typicum: Valanginian-Hauterivian
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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.
Phoberocysta lowryi Backhouse, 1987. Phoberocysta lowryi differs from P.neocomica in having a distinctly rhomboidal outline and two antapical horns. P.burgeri is similar in shape, but shows greater separation between the wall layers on the hypocyst and possesses broader and longer horns. P. burgeri appears to be less spinose and in one variant has the spines restricted to the base of the horns. Phoberocysta lowryi and P. burgeri belong to the same morphocline. P. lowryi appeard first and with an increased cavation and an overall increase in size evolved into P. burgeri. This is a taxonomic junior synonym of Muderongia testudinaria according to Monteil (1991b). Size: length with operculum missing 74-116 µm, , total width 72-106 µm, length of endocyst with operculum missing 47-70 µm, width 52-72 µm
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Original description: Backhouse, 1987, p. 219
Cyst cornucavate, dorsoventrally flattened, rhomboidal in outline with an apical, 2
antapical and 2 lateral horns. Endophragm about 0.5 µm thick, forming a smooth rhomboidal endocyst with a broadly rounded to truncate antapex. Small knob-like protrusions of the endocyst formed on some specimens at the positions of the lateral and apical horns. Periphragm less than 0.5 µm thick, dorsally and ventrally appressed to the endophragm. Cyst cavate apically, antapically and laterally where spinose horns are formed. Paratabulation well-developed near the margins of the cyst; expressed by variably developed parasutural septa 0.5-4 µm high, bearing spines up to 12 µm high. Each parasutural spine arising from a broad base, tapering to a narrow strand and then expanding to a truncated tip. On well-preserved specimens the septa in the precingular and postcingular series dividing to form paired septa along much of their length. The observed paratabulation formula ?4', 6'', Xc, 5''', 1'''', paraplates 1''' to 5''' in the 2''' to 6''' positions. Antapical horns positioned ventral to the mid plane 15-33 µm long; left horn slightly longer than the right and slightly more ventral in position. Ventral parasutural septa extending towards the antapical horns; horns bearing lateral spines similar to those of the septa. Apical horn narrow, up to 40µm long, bearing lateral spines. Lateral horns 10 to 36 µm in length, bent antapically at a notch in the mid section. Lateral horns formed by extensions of the paracingulum and paraplates of the precingular and postcingular series. Each lateral horn bearing 3 well-developed spinose septa, some of which may be paired septa. Paracingulum poorly expressed on the mid-dorsal and mid-ventral areas, expressed ventrally on the lateral horns by low septa bearing relatively short spines. Only 2 paracingular cross septa developed, one near the base of each lateral horn on the dorsal surface (Fig.7B). Archeopyle
apical, type [tA]; operculum detached. Archeopyle suture showing a deep sulcal notch and a broad 6" paraplate.
Dimensions. Length of holotype with operculum missing 88 µm, total width 106 µm; length of endocyst with operculum missing 53 µm, width 56 µm. Range of length with operculum missing (11 specimens) 74(90)116 µm, total width 72(93)106 µm; length of endocyst with operculum missing (13 specimens) 47(60)70 µm, width 52(60)72 µm. Total length including operculum approximately 150 µm.
Affinities:
Backhouse, 1988, p. 219: Phoberocysta lowryi is distinguished from P. neocomica (Gocht) Millioud 1969 by its distinctly rhomboidal outline and 2 antapical horns. Phoberocysta tabulata Raynaud 1978 possesses higher septa, an oval outline and in most cases, only a single, long antapical horn. Phoberocysta burgeri Helby (this memoir) is similar to P. Iowryi in shape, but shows greater separation between the wall layers on the hypocyst and possesses broader and longer horns. Phoberocysta burgeri appears to be less spinose than P. Iowryi and at one morphological extreme spines are restricted to areas at the bases of the horns. Phoberocysta lowryi and P. burgeri belong to the same morphocline. Phoberocysta lowryi appeared first and with an increased cavation and an overall increase in size evolved into P. burgeri. Specific ranges of the two forms overlap only slightly, if at all, in the Perth Basin. Evitt (1961, pl.8, figs 1,2) and Wall & Evitt (1975, p.3, fig.9) illustrated an unnamed form from the Early Cretaceous of Pakistan which may be a specimen of P. Iowryi.
Tax. jr. synonym of Muderongia testudinaria Burger, 1980, according to Monteil, 1991.
Holotype: Backhouse, 1987, fig. 12C-D
Locus typicus: Perth Basin, Australia
Stratum typicum: Valanginian-Hauterivian
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Phoberocysta lowryi Backhouse, 1987. Phoberocysta lowryi differs from P.neocomica in having a distinctly rhomboidal outline and two antapical horns. P.burgeri is similar in shape, but shows greater separation between the wall layers on the hypocyst and possesses broader and longer horns. P. burgeri appears to be less spinose and in one variant has the spines restricted to the base of the horns. Phoberocysta lowryi and P. burgeri belong to the same morphocline. P. lowryi appeard first and with an increased cavation and an overall increase in size evolved into P. burgeri. This is a taxonomic junior synonym of Muderongia testudinaria according to Monteil (1991b). Size: length with operculum missing 74-116 µm, , total width 72-106 µm, length of endocyst with operculum missing 47-70 µm, width 52-72 µm
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Original description: Backhouse, 1987, p. 219
Cyst cornucavate, dorsoventrally flattened, rhomboidal in outline with an apical, 2
antapical and 2 lateral horns. Endophragm about 0.5 µm thick, forming a smooth rhomboidal endocyst with a broadly rounded to truncate antapex. Small knob-like protrusions of the endocyst formed on some specimens at the positions of the lateral and apical horns. Periphragm less than 0.5 µm thick, dorsally and ventrally appressed to the endophragm. Cyst cavate apically, antapically and laterally where spinose horns are formed. Paratabulation well-developed near the margins of the cyst; expressed by variably developed parasutural septa 0.5-4 µm high, bearing spines up to 12 µm high. Each parasutural spine arising from a broad base, tapering to a narrow strand and then expanding to a truncated tip. On well-preserved specimens the septa in the precingular and postcingular series dividing to form paired septa along much of their length. The observed paratabulation formula ?4', 6'', Xc, 5''', 1'''', paraplates 1''' to 5''' in the 2''' to 6''' positions. Antapical horns positioned ventral to the mid plane 15-33 µm long; left horn slightly longer than the right and slightly more ventral in position. Ventral parasutural septa extending towards the antapical horns; horns bearing lateral spines similar to those of the septa. Apical horn narrow, up to 40µm long, bearing lateral spines. Lateral horns 10 to 36 µm in length, bent antapically at a notch in the mid section. Lateral horns formed by extensions of the paracingulum and paraplates of the precingular and postcingular series. Each lateral horn bearing 3 well-developed spinose septa, some of which may be paired septa. Paracingulum poorly expressed on the mid-dorsal and mid-ventral areas, expressed ventrally on the lateral horns by low septa bearing relatively short spines. Only 2 paracingular cross septa developed, one near the base of each lateral horn on the dorsal surface (Fig.7B). Archeopyle
apical, type [tA]; operculum detached. Archeopyle suture showing a deep sulcal notch and a broad 6" paraplate.
Dimensions. Length of holotype with operculum missing 88 µm, total width 106 µm; length of endocyst with operculum missing 53 µm, width 56 µm. Range of length with operculum missing (11 specimens) 74(90)116 µm, total width 72(93)106 µm; length of endocyst with operculum missing (13 specimens) 47(60)70 µm, width 52(60)72 µm. Total length including operculum approximately 150 µm.
Affinities:
Backhouse, 1988, p. 219: Phoberocysta lowryi is distinguished from P. neocomica (Gocht) Millioud 1969 by its distinctly rhomboidal outline and 2 antapical horns. Phoberocysta tabulata Raynaud 1978 possesses higher septa, an oval outline and in most cases, only a single, long antapical horn. Phoberocysta burgeri Helby (this memoir) is similar to P. Iowryi in shape, but shows greater separation between the wall layers on the hypocyst and possesses broader and longer horns. Phoberocysta burgeri appears to be less spinose than P. Iowryi and at one morphological extreme spines are restricted to areas at the bases of the horns. Phoberocysta lowryi and P. burgeri belong to the same morphocline. Phoberocysta lowryi appeared first and with an increased cavation and an overall increase in size evolved into P. burgeri. Specific ranges of the two forms overlap only slightly, if at all, in the Perth Basin. Evitt (1961, pl.8, figs 1,2) and Wall & Evitt (1975, p.3, fig.9) illustrated an unnamed form from the Early Cretaceous of Pakistan which may be a specimen of P. Iowryi.