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Perisseiasphaeridium ingegerdiae
Perisseiasphaeridium ingegerdiae Nohr-Hansen, 1986
Holotype: Nohr-Hansen, 1986, pl.3, fig.11; Stancliffe and Sarjeant, 1990, pl.3, fig.2
Locus typicus: Clay-pit of Blue Circle Portland Cement Company at Westbury, Wiltshire
Stratum typicum: Jurassic
Age: Early Kimmeridgian
Occurrence: Present from the lower part of the Mutabllis Zone to the lower part of the Eudoxus Zone.
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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.
Perisseiasphaeridium ingegerdiae Nøhr-Hansen. Diagnosis from Nøhr-Hansen (1986, p.35-36). Skolochorate cysts with a subspherical central body. The cysts possess two types of processes; 1. Large, thick, hollow, tubiform processes and 2. Slender, massive processes. The processes are intratabular and proximally striate occasionally with “supporting roots”. The processes indicate a gonyaulacoid tabulation. The wall is composed of two layers, endophragm and periphragm. The archeopyle is apical tetratabular. The tubiform processes are open distally, often weakly aculeate. The slender paracingular processes are connected basally two by two. Distally they are capitate to bifid.
Size: overall diameter 82-112 µm, diameter of central body 42-60 µm, length of processes 20-30 µm.
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Original diagnosis: Nohr-Hansen, 1986, p. 35-36
Skolochorate cysts with a subspherical central body. The cysts posses two types of processes; (1) large, thick, hollow, tubiform processes and (2) slender, massive processes. The processes are intratabular and proximally striate occasionally with "supporting roots". The processes indicate a gonyaulacoid type of tabulation pattern. The wall is composed of two layers, endophragm and periphragm. The archeopyle is apical type tA.
Original description: Nohr-Hansen, 1986, p. 35-36
Cyst type: Chorate, as the length of the processes exceeds 30% of the shortest diameter of the central body (cf. Sarjeant 1981). Moreover, the cysts are skolochorate on account of the shape and location of the processes (cf. Sarjeant 1981). Shape. The central body is subspherical.
Wall relationship: The cyst wall is composed of two layers. An inner layer, endophragm? forms the interior demarcation of the central body. An outer layer, periphragm, has a vesiculate structure. It forms the outer demarcation of the central body and the processes with supporting roots. Periphragm does not show any parasutural structures. Periphragm forms two types of processes;
Processes: (1) large hollow, tubiform, intratabular processes which are open distally, often weakly aculeate. These processes are proximally striated, as a result of the attachement of the supporting roots. (2) Slender massive, simple processes, which occur in the parasulcal and paracingular areas. The paracingular processes are connected basally, two by two. Distally they are capitate to bifid.
Paratabulation: Paratabulation is indicated by the position and size of the intratabular processes. The pratabulation's formula: 4', 6". 6c(?), 5"', lp (?), 1"", ?s.
Archeopyle: The archeopyle is apical of type tA. Operculum is simple and attached on some specimens, for example on the holotype (pl. 3, fig. 11), but detached on other specimens (pl. 4, fig. 8).
Paracingulum: The zone of the paracingulum is indicated by six pairs of slender massive processes.
Parasulcus: It has not been possible to count the number of processes.
Dimensions:
The overall diameter of the holotype is 104 µm.
The diameter of the central body is 48 my and the maximum length of the processes is 28 µm.
Parameters of 8 specimens are: overall diameter 82(98)112 µm, diameter of central body 42(49)60 µm, length of processes 20(25)30 µm.
Discussion. Nohr-Hansen, 1986, p. 35-36
This species is placed in the genus Perisseiasphaeridium Davey & Williams 1966, on the basis of the following characteristics: skolochorate cysts with large, subspheroidal central body, distally open, tubiform intratabular processes and simple, slender, paracingular processes. P. ingegerdii sp. nov. differs clearly from P. pannosum Davey & Williams 1966, the processes of which are fenestrate with an irregular distal margin. P. ingegerdii sp.nov. is similar to P. insolitum Davey 1982, but this species deviates in having pr'ocesses which are more slender with more regulary aculeate spines. P. ingegerdii sp.nov. differs from Perisseiasphaeridium sp. A. Ioannides et al. 1976 wich has more slender and often fenestrate processes.
Holotype: Nohr-Hansen, 1986, pl.3, fig.11; Stancliffe and Sarjeant, 1990, pl.3, fig.2
Locus typicus: Clay-pit of Blue Circle Portland Cement Company at Westbury, Wiltshire
Stratum typicum: Jurassic
Age: Early Kimmeridgian
Occurrence: Present from the lower part of the Mutabllis Zone to the lower part of the Eudoxus Zone.
--------------------------------------------------
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Perisseiasphaeridium ingegerdiae Nøhr-Hansen. Diagnosis from Nøhr-Hansen (1986, p.35-36). Skolochorate cysts with a subspherical central body. The cysts possess two types of processes; 1. Large, thick, hollow, tubiform processes and 2. Slender, massive processes. The processes are intratabular and proximally striate occasionally with “supporting roots”. The processes indicate a gonyaulacoid tabulation. The wall is composed of two layers, endophragm and periphragm. The archeopyle is apical tetratabular. The tubiform processes are open distally, often weakly aculeate. The slender paracingular processes are connected basally two by two. Distally they are capitate to bifid.
Size: overall diameter 82-112 µm, diameter of central body 42-60 µm, length of processes 20-30 µm.
--------------------------------------------------
Original diagnosis: Nohr-Hansen, 1986, p. 35-36
Skolochorate cysts with a subspherical central body. The cysts posses two types of processes; (1) large, thick, hollow, tubiform processes and (2) slender, massive processes. The processes are intratabular and proximally striate occasionally with "supporting roots". The processes indicate a gonyaulacoid type of tabulation pattern. The wall is composed of two layers, endophragm and periphragm. The archeopyle is apical type tA.
Original description: Nohr-Hansen, 1986, p. 35-36
Cyst type: Chorate, as the length of the processes exceeds 30% of the shortest diameter of the central body (cf. Sarjeant 1981). Moreover, the cysts are skolochorate on account of the shape and location of the processes (cf. Sarjeant 1981). Shape. The central body is subspherical.
Wall relationship: The cyst wall is composed of two layers. An inner layer, endophragm? forms the interior demarcation of the central body. An outer layer, periphragm, has a vesiculate structure. It forms the outer demarcation of the central body and the processes with supporting roots. Periphragm does not show any parasutural structures. Periphragm forms two types of processes;
Processes: (1) large hollow, tubiform, intratabular processes which are open distally, often weakly aculeate. These processes are proximally striated, as a result of the attachement of the supporting roots. (2) Slender massive, simple processes, which occur in the parasulcal and paracingular areas. The paracingular processes are connected basally, two by two. Distally they are capitate to bifid.
Paratabulation: Paratabulation is indicated by the position and size of the intratabular processes. The pratabulation's formula: 4', 6". 6c(?), 5"', lp (?), 1"", ?s.
Archeopyle: The archeopyle is apical of type tA. Operculum is simple and attached on some specimens, for example on the holotype (pl. 3, fig. 11), but detached on other specimens (pl. 4, fig. 8).
Paracingulum: The zone of the paracingulum is indicated by six pairs of slender massive processes.
Parasulcus: It has not been possible to count the number of processes.
Dimensions:
The overall diameter of the holotype is 104 µm.
The diameter of the central body is 48 my and the maximum length of the processes is 28 µm.
Parameters of 8 specimens are: overall diameter 82(98)112 µm, diameter of central body 42(49)60 µm, length of processes 20(25)30 µm.
Discussion. Nohr-Hansen, 1986, p. 35-36
This species is placed in the genus Perisseiasphaeridium Davey & Williams 1966, on the basis of the following characteristics: skolochorate cysts with large, subspheroidal central body, distally open, tubiform intratabular processes and simple, slender, paracingular processes. P. ingegerdii sp. nov. differs clearly from P. pannosum Davey & Williams 1966, the processes of which are fenestrate with an irregular distal margin. P. ingegerdii sp.nov. is similar to P. insolitum Davey 1982, but this species deviates in having pr'ocesses which are more slender with more regulary aculeate spines. P. ingegerdii sp.nov. differs from Perisseiasphaeridium sp. A. Ioannides et al. 1976 wich has more slender and often fenestrate processes.