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Cannosphaeropsis franciscana
Cannosphaeropsis franciscana, Damassa, 1979
Holotype: Damassa, 1979, pl.5, figs.1-2,6
Locus typicus: Coastal Belt, Franciscan complex, California
Stratum typicum: ?Danian
Age: Early Paleocene
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Original description as Cannosphaeropsis franciscana: [Damassa 1979, p. 204, 205]:
Diagnosis:
Cyst composed of autophragm and ectophragm which are connected by regular gonal processes, regular intergonal processes absent. Ectophragm consists of trabeculae which connect apical, lateral and ventral processes near their distal ends. Tips of processes trifurcate and secondarily bifurcate. Processes on dorsal surface not connected by trabeculae.
Archeopyle formed by loss of third precingular paraplate.
Description:
Cyst composed of autophragm and ectophragm, which are connected by regular gonal processes. Cyst without regular intergonal processes. Autophragm ellipsoidal, without horns, ranging in size from 57-73 x 40-59 µm (mean = 63 x 50 µm, of 11 specimens). Thickness of autophragm about 1 µm. Ectophragm consists of trabeculae which connect the apical, lateral, and ventral processes near their distal ends, and indicate a partial paratabulation. Ectophragm perimeter 135-175 x 89-140 µm (mean = 153 x 109 µm, of 11 specimens).
Processes of paraplates 2",4",3c and 4c, 3" "-5" ", and the dorsal margin of 1 " " are not connected by trabeculae. Tips of processes trifurcate and secondarily bifurcate (Pl. 5, fig. 6). Trabeculae and processes 1-4 µm in diameter, cylindrical to flattened, thickness increases toward the base of the processes and intersections of trabeculae. Small bifurcate processes borne on the trabeculae may possibly be interpreted as intergonal processes, but these have no connections to the autophragm (Pl. 5, fig. 3). Apex bears a single long projection which arises from trabeculae connecting the gonal processes located at the apical-precingular paraplate contacts. The projection extends beyond the trabecular perimeter for a distance up to 30 µm. 5, figs. 7, 10). This apical projection, which has minute tendrils along its margin, commonly is folded or crumpled back toward the remainder of the ectophragm. Apical projection as well as trabecular intersections may be perforated.
Archeopyle Type P, formed by loss of the third precingular paraplate. Archeopyle margin rectangular to pentagonal; operculum free.
Surfaces of autophragm, ectophragm and processes appear smooth at magnifications up to 2000x.
Paratabulation: ?4 ", ?6", ?6c, s, ?lp, ?5 " ", 1 " ". Inferred thecal tabulation: 4", 6", 6c, 5s, lp, 6", 1""
Remarks:
Cannosphaeropsis franciscana has previously been reported by Drugg (1967, p. 25, Pl. 4, fig. 16) from the Dos Palos Member of the Moreno Formation as Cannosphaeropsis filifera (Cookson and Eisenack) Cookson and Eisenack 1960. Comparison of Drugg's specimens (Pl. 5, figs. 8, 9) with those from the Coastal Belt indicates that Drugg's specimens should not be assigned to C. filifera (Cookson and Eisenack) Cookson and Eisenack 1960, but that they are actually conspecific with Cannosphaeropsis franciscana. (Note: Cannosphaeropsis filifera was transferred to the genus Adnatosphaeridium as A. filiferum by Williams and Downie in Davey, et al., 1969.) C. franciscana may be distinguished from C. utinensis, the type species, by the incomplete development of paratabulation as indicated by the trabeculae, and by the presence of the apical projection. The lack of dorsal trabeculae was observed in all well-preserved specimens, and is a characteristic feature of the species. The detailed pattern of trabeculae-process connections is variable, but the overall structure is consistent. The most regular features are: (1) the two unconnected processes at the dorsal corners of the antapical paraplate (Pl. 5, figs. 2, 11); (2) the pyramidal outline of the trabecular network in the apical region (Pl. 5, figs. 10, 11); (3) the circular perimeter of the ectophragm around the paracingulum (Pl. 4, fig. 7); (4) the lack of trabeculae on the dorsal surface (Pl. 4, fig. 7; Pl. 5, fig. 11); (5) the presence of a trabecular "ring" in a position which roughly corresponds to the location of paraplates lc, 1 " ", 2" ", and lp (Pl. 5, figs. 3, 4). In some individuals it is possible to infer paraplate shapes by inspection of the trabeculae, but in general the trabeculae-process network is too incomplete or distorted to allow a definite determination of paraplate configuration. A Spiniferites-like paratabulation is inferred by analogy with other taxa in this group (i.e. Spiniferites, Achomosphaera, and Nematosphaeropsis).
Holotype: Damassa, 1979, pl.5, figs.1-2,6
Locus typicus: Coastal Belt, Franciscan complex, California
Stratum typicum: ?Danian
Age: Early Paleocene
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Original description as Cannosphaeropsis franciscana: [Damassa 1979, p. 204, 205]:
Diagnosis:
Cyst composed of autophragm and ectophragm which are connected by regular gonal processes, regular intergonal processes absent. Ectophragm consists of trabeculae which connect apical, lateral and ventral processes near their distal ends. Tips of processes trifurcate and secondarily bifurcate. Processes on dorsal surface not connected by trabeculae.
Archeopyle formed by loss of third precingular paraplate.
Description:
Cyst composed of autophragm and ectophragm, which are connected by regular gonal processes. Cyst without regular intergonal processes. Autophragm ellipsoidal, without horns, ranging in size from 57-73 x 40-59 µm (mean = 63 x 50 µm, of 11 specimens). Thickness of autophragm about 1 µm. Ectophragm consists of trabeculae which connect the apical, lateral, and ventral processes near their distal ends, and indicate a partial paratabulation. Ectophragm perimeter 135-175 x 89-140 µm (mean = 153 x 109 µm, of 11 specimens).
Processes of paraplates 2",4",3c and 4c, 3" "-5" ", and the dorsal margin of 1 " " are not connected by trabeculae. Tips of processes trifurcate and secondarily bifurcate (Pl. 5, fig. 6). Trabeculae and processes 1-4 µm in diameter, cylindrical to flattened, thickness increases toward the base of the processes and intersections of trabeculae. Small bifurcate processes borne on the trabeculae may possibly be interpreted as intergonal processes, but these have no connections to the autophragm (Pl. 5, fig. 3). Apex bears a single long projection which arises from trabeculae connecting the gonal processes located at the apical-precingular paraplate contacts. The projection extends beyond the trabecular perimeter for a distance up to 30 µm. 5, figs. 7, 10). This apical projection, which has minute tendrils along its margin, commonly is folded or crumpled back toward the remainder of the ectophragm. Apical projection as well as trabecular intersections may be perforated.
Archeopyle Type P, formed by loss of the third precingular paraplate. Archeopyle margin rectangular to pentagonal; operculum free.
Surfaces of autophragm, ectophragm and processes appear smooth at magnifications up to 2000x.
Paratabulation: ?4 ", ?6", ?6c, s, ?lp, ?5 " ", 1 " ". Inferred thecal tabulation: 4", 6", 6c, 5s, lp, 6", 1""
Remarks:
Cannosphaeropsis franciscana has previously been reported by Drugg (1967, p. 25, Pl. 4, fig. 16) from the Dos Palos Member of the Moreno Formation as Cannosphaeropsis filifera (Cookson and Eisenack) Cookson and Eisenack 1960. Comparison of Drugg's specimens (Pl. 5, figs. 8, 9) with those from the Coastal Belt indicates that Drugg's specimens should not be assigned to C. filifera (Cookson and Eisenack) Cookson and Eisenack 1960, but that they are actually conspecific with Cannosphaeropsis franciscana. (Note: Cannosphaeropsis filifera was transferred to the genus Adnatosphaeridium as A. filiferum by Williams and Downie in Davey, et al., 1969.) C. franciscana may be distinguished from C. utinensis, the type species, by the incomplete development of paratabulation as indicated by the trabeculae, and by the presence of the apical projection. The lack of dorsal trabeculae was observed in all well-preserved specimens, and is a characteristic feature of the species. The detailed pattern of trabeculae-process connections is variable, but the overall structure is consistent. The most regular features are: (1) the two unconnected processes at the dorsal corners of the antapical paraplate (Pl. 5, figs. 2, 11); (2) the pyramidal outline of the trabecular network in the apical region (Pl. 5, figs. 10, 11); (3) the circular perimeter of the ectophragm around the paracingulum (Pl. 4, fig. 7); (4) the lack of trabeculae on the dorsal surface (Pl. 4, fig. 7; Pl. 5, fig. 11); (5) the presence of a trabecular "ring" in a position which roughly corresponds to the location of paraplates lc, 1 " ", 2" ", and lp (Pl. 5, figs. 3, 4). In some individuals it is possible to infer paraplate shapes by inspection of the trabeculae, but in general the trabeculae-process network is too incomplete or distorted to allow a definite determination of paraplate configuration. A Spiniferites-like paratabulation is inferred by analogy with other taxa in this group (i.e. Spiniferites, Achomosphaera, and Nematosphaeropsis).