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Palaeohystrichophora infusorioides
Palaeohystrichophora infusoroides Deflandre, 1935, p.230-231
Taxonomic junior synonym: Palaeohystrichophora paucisetosa, according to Aurisano (1989, p.170).
This species was not validly published in Deflandre (1934, caption to fig.8 — p.967) since no description was provided. A full description was given in Deflandre (1936b, p.186–187).
Holotype: Deflandre, 1935, pl.8, fig.4; Deflandre, 1936, pl.9, fig.7
Locus typicus: Paris, France
Stratum typicum: ?Senonian
Translation Deflandre, 1936: LPP, after the annotated description of Deflandre's 1936 lengthly description, by Eisenack, 1964, p. 581-582
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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.
Palaeohystrichophora infusorioides Deflandre, 1935. Harker (1979) stated that this species had a long pointed left and shorter right antapical horn. There are small apical and antapical pericoels. Endocyst smooth to finely granular, pericyst with nontabular, fine, needle-like, frequently curved, solid spines. Cingulum slightly laevorotatory. Davey (1970) thought that this species has a precingular archeopyle. Harker believes it is a 3I3Pa/3I3Pa archeopyle.
Size of Harker’s specimens: overall length 37-95 µm, overall width 24-46 µm. Size of Deflandre’s type material, length 30-48 µm.
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Original description: Deflandre 1935, p. 230-231
Annotated diagnosis: Deflandre, 1936, p. 186
Nearly all specimens give the impression of being encysted, or at least getting encysted. This impression is given by the presence of a double system of membranes, one internal, globular and compressed, in which a poorly expressed furrow is imprinted, the other external, largely fusiform, extremely thin and transparent, on which the characteristical hairs are fixed. These hairs are always more neatly preserved at one of the poles, (apex), so that an epitheca, a little longer than the epitheca, can be distinguished. The hairs seem to be irregularly distributed, except on the edges of the transverse furrow, where they are perfectly aligned, but without being regularly equidistant.
The hairs, which are more robust on the entire central part, and particularly around the furrow, are very flexible, recurved in all directions, and sometimes even curled.
Cookson and Eisenack, 1958, p. 37
The Australian examples of this species agree closely with the French types from Villers-sur-Mer (Cenomanian Flints) and the Paris Basin (?Senonian Flints) described by Deflandre. As far as can be judged from the magnification of Deflandre's figures (no measurements are recorded in the text), the Australian specimens are somewhat larger than their French counterparts having an overall range in length of 47-71 µm and breadth of 33-37 µm.
Harker 1979, p. 374
Description: Specimens of P.infusorioides possess a pericyst with a distinctly peridinioid subpentagonal to fusiform ambitus bearing a single tapering apical horn, a long pointed left and a shorter rounded right antapical horn. In 204 measured specimens from North American Santonian and Campanian material the overall length varies from 37-95 µm, mean 58 µm and the overall breadth varies from 24-46 µm, mean 35 µm (Harker 1978). The endocyst has an ovoidal ambitus, protruding more into the epicyst than the hypocyst; it is frequently closely adpressed laterally to the pericyst, leaving only a small apical and antapical pericoel (fig.2, 1,2). Both pericyst and endocyst are very thin walled(phragma less than one µm thick) and do not accept stain readily. The endocyst is smooth walled to finely granular, whereas the pericyst bears an ornament of non-tabular, fine, needle-like, frequently curved, solid spines. The only easily recognisable feature of paratabulation is the slightly laevorotatory paracingulum, represented by low parasutures and an alignment of spines on the pericyst. Specimens from the Santonian and Campanian of Saskatchewan, Manitoba, North Dakota and Texas, compare favorably with Deflandre's type material from Upper Cretaceous flints of France. Like the holotype, most of the observed specimens show little, if any, indication of archeopyle formation. However, a large mid-dorsal area on the epicyst is sometimes outlined by minor folds and partially opened linear fractures (fig.1a, fig.2). Observation of similar features may have led Davey (1970: 345-6) to consider that P.infusorioides possesses a precingular archeopyle. A detailed study of several well preserved specimens from Austin Chalk and Taylor Clay of Texas has shown that the mode of archeopyle formation is not a simple precingular type but is a combination type involving three anterior intercalary and three precingular paraplates in both pericyst and endocyst (3I3Pa, 3I3 Pa; 1a-3a/3-5'', 1a-3a/3-5''). The simple operculum consists of both perioperculum and endooperculum, since the periphragm and endophragm are closely adpressed in the region of the archeopyle. The operculum usually remains intact, in place and is attached posteriorly, apparently acting as a flap during encystment. Accessory archeopyle sutures indicate that the operculum is composed of three intercalary (1a-3a) and three precingular (3''-5'') paraplates (fig.1b,c; fig.2). Very few specimens were observed to possess accessory archeopyle sutures and their development is probably enhanced by post-excystment mechanical damage.
Taxonomic junior synonym: Palaeohystrichophora paucisetosa, according to Aurisano (1989, p.170).
This species was not validly published in Deflandre (1934, caption to fig.8 — p.967) since no description was provided. A full description was given in Deflandre (1936b, p.186–187).
Holotype: Deflandre, 1935, pl.8, fig.4; Deflandre, 1936, pl.9, fig.7
Locus typicus: Paris, France
Stratum typicum: ?Senonian
Translation Deflandre, 1936: LPP, after the annotated description of Deflandre's 1936 lengthly description, by Eisenack, 1964, p. 581-582
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Palaeohystrichophora infusorioides Deflandre, 1935. Harker (1979) stated that this species had a long pointed left and shorter right antapical horn. There are small apical and antapical pericoels. Endocyst smooth to finely granular, pericyst with nontabular, fine, needle-like, frequently curved, solid spines. Cingulum slightly laevorotatory. Davey (1970) thought that this species has a precingular archeopyle. Harker believes it is a 3I3Pa/3I3Pa archeopyle.
Size of Harker’s specimens: overall length 37-95 µm, overall width 24-46 µm. Size of Deflandre’s type material, length 30-48 µm.
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Original description: Deflandre 1935, p. 230-231
Annotated diagnosis: Deflandre, 1936, p. 186
Nearly all specimens give the impression of being encysted, or at least getting encysted. This impression is given by the presence of a double system of membranes, one internal, globular and compressed, in which a poorly expressed furrow is imprinted, the other external, largely fusiform, extremely thin and transparent, on which the characteristical hairs are fixed. These hairs are always more neatly preserved at one of the poles, (apex), so that an epitheca, a little longer than the epitheca, can be distinguished. The hairs seem to be irregularly distributed, except on the edges of the transverse furrow, where they are perfectly aligned, but without being regularly equidistant.
The hairs, which are more robust on the entire central part, and particularly around the furrow, are very flexible, recurved in all directions, and sometimes even curled.
Cookson and Eisenack, 1958, p. 37
The Australian examples of this species agree closely with the French types from Villers-sur-Mer (Cenomanian Flints) and the Paris Basin (?Senonian Flints) described by Deflandre. As far as can be judged from the magnification of Deflandre's figures (no measurements are recorded in the text), the Australian specimens are somewhat larger than their French counterparts having an overall range in length of 47-71 µm and breadth of 33-37 µm.
Harker 1979, p. 374
Description: Specimens of P.infusorioides possess a pericyst with a distinctly peridinioid subpentagonal to fusiform ambitus bearing a single tapering apical horn, a long pointed left and a shorter rounded right antapical horn. In 204 measured specimens from North American Santonian and Campanian material the overall length varies from 37-95 µm, mean 58 µm and the overall breadth varies from 24-46 µm, mean 35 µm (Harker 1978). The endocyst has an ovoidal ambitus, protruding more into the epicyst than the hypocyst; it is frequently closely adpressed laterally to the pericyst, leaving only a small apical and antapical pericoel (fig.2, 1,2). Both pericyst and endocyst are very thin walled(phragma less than one µm thick) and do not accept stain readily. The endocyst is smooth walled to finely granular, whereas the pericyst bears an ornament of non-tabular, fine, needle-like, frequently curved, solid spines. The only easily recognisable feature of paratabulation is the slightly laevorotatory paracingulum, represented by low parasutures and an alignment of spines on the pericyst. Specimens from the Santonian and Campanian of Saskatchewan, Manitoba, North Dakota and Texas, compare favorably with Deflandre's type material from Upper Cretaceous flints of France. Like the holotype, most of the observed specimens show little, if any, indication of archeopyle formation. However, a large mid-dorsal area on the epicyst is sometimes outlined by minor folds and partially opened linear fractures (fig.1a, fig.2). Observation of similar features may have led Davey (1970: 345-6) to consider that P.infusorioides possesses a precingular archeopyle. A detailed study of several well preserved specimens from Austin Chalk and Taylor Clay of Texas has shown that the mode of archeopyle formation is not a simple precingular type but is a combination type involving three anterior intercalary and three precingular paraplates in both pericyst and endocyst (3I3Pa, 3I3 Pa; 1a-3a/3-5'', 1a-3a/3-5''). The simple operculum consists of both perioperculum and endooperculum, since the periphragm and endophragm are closely adpressed in the region of the archeopyle. The operculum usually remains intact, in place and is attached posteriorly, apparently acting as a flap during encystment. Accessory archeopyle sutures indicate that the operculum is composed of three intercalary (1a-3a) and three precingular (3''-5'') paraplates (fig.1b,c; fig.2). Very few specimens were observed to possess accessory archeopyle sutures and their development is probably enhanced by post-excystment mechanical damage.