Back
Cordosphaeridium biarmatum
Cordosphaeridium biarmatum, Morgenroth, 1966
Originally (and now) Cordosphaeridium, subsequently Tityrosphaeridium?.
Sarjeant, 1981, provisionally transferred this species to Tityrosphaeridium Sarjeant, 1981. Lentin and Williams, 1985, retained it in Cordosphaeridium.
Holotype: Morgenroth, 1966, pl.4, figs.6-7
Locus typicus: Katharinehof Fehmarn.
Stratum typicum: Lower Eocene (?2).
Age: Early Eocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description as Cordosphaeridium biarmatum: [Morgenroth 1966a, p. 21]: (Translation: Geological Survey of Canada):
Diagnosis:
A species of the genus Cordosphaeridium with different process types. These are: a) small and simply pointed, b) wide and more or less cylindrical in form. Irregular arrangement of the processes. Capsule ellipsoidal.
Description:
The capsule has a clearly ellipsoidal form.The capsule wall can be clearly differentiated into two layers of which the outer has a fibrous structure and a clear aerolation on the capsule surface.
The processes are formed through the fusing of the fibers of the outer shell. They are colorless, transparent and are of different lengths, forms and widths (compare Fig. 7). So, we can find on the same specimens solid, thin, pointed to broad, cylindrical processes. The latter are distally closed by a membrane (or skin). The pyrite deposits visible in optical section ( oil immersion) seem to indicate that the broad processes are hollow. Furthermore, at the outer end of the broader processes we find tiny branches (see Fig. 7).
Almost all specimens possess a pylome whose form is mostly ellipsoidal, but occasionally circular.
Dimensions:
Capsule length: 53 microns (45/59 microns), capsule breadth: 48 microns (45/50 microns), process length: 26 microns (11/36 microns), pylome diameter approximately: 23 x 29 microns (25 measurements). Number of specimens examined: 41.
Remarks:
Only in Cordosphaeridium biarmatum are the irregularly distributed distally closed processes characteristic of which two types are especially or particularly dominant. 1) Small, solid simply pointed processes, 2) broad cylindrical processes that are distally closed and possess clearly hollow interiors. Despite the similarity to the genus Baltisphaeridium (also with hollow distally closed processes) the new species must be placed in the genus Cordosphaeridium on account of the fine structured characteristics described.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Supplemental description and remarks (Cordosphaeridium cf. biarmatum):
Gocht, 1969, p.44, 45:
Description and Remarks:
The body is spherical to ellipsoidal, and consists of a usually strong inner membrane and a fragile outer membrane with fibrous structure. The shape of the processes is exceptionally variable, with many stages from thin scales to large, saccate or cylindrical appendages. Nevertheless, the process shapes and arrangement conform to rules. The arrangement is based closely on that of C. inodes.
The archeopyle is horseshoe-shaped.
Below it, there is a series of cingular processes which vary in shape and number from one individual to another. Fusions into longer strips occur, sometimes with arcuate recesses along the base and the distal edge. Other specimens have only narrow, long, and unbranched appendages at the cingular level. The processes at the poles, and the dorsally located pre- and postcingulars usually take the form of broad, thickset, hollow membrane structures, viz., process groups B and D and the azygous processes P and E (cf. the description of C. inodes). The apical process AP can again be divided into several partial processes, which sometimes remain connected at the base. In the cingular region, we find a variable number of predominantly narrow, unbranched or singly furcate appendages. As in other Cordosphaeridium species, fibrous strands traverse the entire membrane surface and radiate into bases of the processes. My material deviates in some respects from the original description by Morgenroth, 1966. First, in spite of all the variation, the process arrangement is subject to rules. The central bodies are usually elongate, but also globose forms occur. Finally, the thin processes, at least proximally, were found to be hollow.
There are morphological affinities also with Hystrichokolpoma biformoides (Eisenack, 1954). The assignment of the latter species to the genus Hystrichokolpoma has become somewhat questionable again because of its precingular archeopyle. Unlike the finds described here, H. biformoides has a large antapical process. Also the outer membrane is less distinctly fibrous. And the process arrangement seems to be different. Another morphologically closely related species with hollow, narrow- and wide-lumen appendages on the same body is Hystrichosphaeridium ferox Deflandre, 1937 from the Late and Early Cretaceous.
Dimensions:
Maximal extension: 91-121 µm. Main body diameter 57-72 µm.
Originally (and now) Cordosphaeridium, subsequently Tityrosphaeridium?.
Sarjeant, 1981, provisionally transferred this species to Tityrosphaeridium Sarjeant, 1981. Lentin and Williams, 1985, retained it in Cordosphaeridium.
Holotype: Morgenroth, 1966, pl.4, figs.6-7
Locus typicus: Katharinehof Fehmarn.
Stratum typicum: Lower Eocene (?2).
Age: Early Eocene
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description as Cordosphaeridium biarmatum: [Morgenroth 1966a, p. 21]: (Translation: Geological Survey of Canada):
Diagnosis:
A species of the genus Cordosphaeridium with different process types. These are: a) small and simply pointed, b) wide and more or less cylindrical in form. Irregular arrangement of the processes. Capsule ellipsoidal.
Description:
The capsule has a clearly ellipsoidal form.The capsule wall can be clearly differentiated into two layers of which the outer has a fibrous structure and a clear aerolation on the capsule surface.
The processes are formed through the fusing of the fibers of the outer shell. They are colorless, transparent and are of different lengths, forms and widths (compare Fig. 7). So, we can find on the same specimens solid, thin, pointed to broad, cylindrical processes. The latter are distally closed by a membrane (or skin). The pyrite deposits visible in optical section ( oil immersion) seem to indicate that the broad processes are hollow. Furthermore, at the outer end of the broader processes we find tiny branches (see Fig. 7).
Almost all specimens possess a pylome whose form is mostly ellipsoidal, but occasionally circular.
Dimensions:
Capsule length: 53 microns (45/59 microns), capsule breadth: 48 microns (45/50 microns), process length: 26 microns (11/36 microns), pylome diameter approximately: 23 x 29 microns (25 measurements). Number of specimens examined: 41.
Remarks:
Only in Cordosphaeridium biarmatum are the irregularly distributed distally closed processes characteristic of which two types are especially or particularly dominant. 1) Small, solid simply pointed processes, 2) broad cylindrical processes that are distally closed and possess clearly hollow interiors. Despite the similarity to the genus Baltisphaeridium (also with hollow distally closed processes) the new species must be placed in the genus Cordosphaeridium on account of the fine structured characteristics described.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Supplemental description and remarks (Cordosphaeridium cf. biarmatum):
Gocht, 1969, p.44, 45:
Description and Remarks:
The body is spherical to ellipsoidal, and consists of a usually strong inner membrane and a fragile outer membrane with fibrous structure. The shape of the processes is exceptionally variable, with many stages from thin scales to large, saccate or cylindrical appendages. Nevertheless, the process shapes and arrangement conform to rules. The arrangement is based closely on that of C. inodes.
The archeopyle is horseshoe-shaped.
Below it, there is a series of cingular processes which vary in shape and number from one individual to another. Fusions into longer strips occur, sometimes with arcuate recesses along the base and the distal edge. Other specimens have only narrow, long, and unbranched appendages at the cingular level. The processes at the poles, and the dorsally located pre- and postcingulars usually take the form of broad, thickset, hollow membrane structures, viz., process groups B and D and the azygous processes P and E (cf. the description of C. inodes). The apical process AP can again be divided into several partial processes, which sometimes remain connected at the base. In the cingular region, we find a variable number of predominantly narrow, unbranched or singly furcate appendages. As in other Cordosphaeridium species, fibrous strands traverse the entire membrane surface and radiate into bases of the processes. My material deviates in some respects from the original description by Morgenroth, 1966. First, in spite of all the variation, the process arrangement is subject to rules. The central bodies are usually elongate, but also globose forms occur. Finally, the thin processes, at least proximally, were found to be hollow.
There are morphological affinities also with Hystrichokolpoma biformoides (Eisenack, 1954). The assignment of the latter species to the genus Hystrichokolpoma has become somewhat questionable again because of its precingular archeopyle. Unlike the finds described here, H. biformoides has a large antapical process. Also the outer membrane is less distinctly fibrous. And the process arrangement seems to be different. Another morphologically closely related species with hollow, narrow- and wide-lumen appendages on the same body is Hystrichosphaeridium ferox Deflandre, 1937 from the Late and Early Cretaceous.
Dimensions:
Maximal extension: 91-121 µm. Main body diameter 57-72 µm.