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Daveya boresphaera
Daveya boresphaera Monteil 1996
Holotype: Monteil 1996, Pl. 1, fig. 1-9; Pl. 2, fig. 1-9
Paratypes: Monteil 1996, Pl. 7, fig. 7-10 (Forma A), Pl. 5, fig. 1-9 (Forma B)
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Monteil 1996, p. 41-42
Daveya boresphaera sp. nov. (Pl. 1, fig. 1-9; Pl. 2, fig. 1-9; Pl. 3, fig. 1-9; Pl. 4, fig. 1-9; Pl. 5, fig. 1-9; Pl. 6, fig. 1-12; Pl. 7, fig. 1-10; Pl. 8, fig. 1-7; Fig. 2, 3, 4)
1979. Gonyaulacysta sp. A.- DAVEY, P. 61; pl. 4, fig. 6; text-fig. 5.
1982. Gonyaulacysta sp. A.- DAVEY, P. 29; pl. 10, fig. 3; fig. 3.
1982. Gonyaulacysta sp. B.- DAVEY, P. 29; fig. 3.
1988. Gonyaulacysta sp. A.- DAVEY, fig. 6.
1992. Gonyaulacysta sp. A.- COSTA & DAVEY, pl. 3.1, fig. 8; fig. 3.3.
Holotype: Pl. 1, fig. 1-9; Pl. 2, fig. 1-9. Slide 17.02 m /01, England Finder coordinates N32 (forma A/B).
Paratype 1: Pl. 5, fig. 1-9. Slide 17.02 m /01 England Finder coordinates F21 (forma B).
Paratype 2: Pl. 7, fig. 7-10. Slide 17.02 m /01, England Finder coordinates M 25/4 (forma A).
Type-locality: IKU core 82-7B (65¦ 05" 57.80" N; 10o 17" 34.10" E), Offshore Mid-Norway, Trondelag Platform, north-eastern Froan Basin.
Type-strata: Depth 17.02 m, Upper Ryazanian (Stenomphalus Ammonite Zone).
Diagnosis: (same as for the genus):
Shape. Typically spherical, with a very short apical horn, formed by linking of intratabular ornamentation and preapical/apical parasutures (Pl. 5, fig. 8, 9; Pl. 7, fig. 7-9; Pl. 8, fig. 7).
Wall relationships. Undifferentiated autophragm, thick and spongious; two appressed wall layers, pedium and luxuria, detectable using SEM (Pl. 8, fig. 6).
Wall features. Low parasutural septa (Pl. 7, fig. 7-10), rows of tubercles, bacula or pila (Pl. 3, fig. 1-9), or high parasutural septa proximally perforated and surmounted by long spines (Pl. 6, fig. 10-12; Pl. 8, fig. 2; Fig. 4); intratabular ornamentation tuberculate, baculate, pilate or echinate, with relief elements isolated (Pl. 6, fig. 4, 5) or distally linked (Pl. 3, fig. 2-5; Pl. 5, fig. 2).
Archeopyle. Precingular type P3..; operculum typically adherent.
Paratabulation. Clearly expressed by parasutural features; gonyaulacacean, formula: 2pr, Oa, 4", 6"", 6c, 6""", 1p, 1""""; ?ras, 2 fpi (Fig. 2, 3). Peculiarities: 4"/1" apical parasuture very clearIy marked (Pl. 1, fig. 1, 2; Pl. 2, fig. 1, 2; Pl. 4, fig. 1-7; Pl. 5, fig. 7-9; Pl. 7, fig. 9, 10); paraplate apical 4" in contact with the anterior extremity (as border) of parasulcus (A/ai-arrangement of HELENES, 1986; Pl. 7, fig. 2); paraplates 1""" very long, narrow, and completely delineated by parasutures, 2""" large, 1p small and very posteriorly situated (Pl. 1, fig. 1, 2; Pl. 2, fig. 1, 2; Pl. 5, fig. 5-6; Pl. 6, fig. 1-3, 10-11; Pl. 8, fig. 5); paraplate 4""" asymmetrical (Pl. 8, fig. 1).
Paracingulum. Indicated by six rectangular transversely elongate paraplates; laevorotatory.
Parasulcus. Indicated by bordering parasutural features and central depression, slightly sigmoidal; subdivision not discernible, except for the questionable ras (Pl. 8, fig. 5); flagellar pore imprint marked by two deeper depressions (Pl. 1, fig. 4; Pl. 2, fig. 4; Pl. 8, fig. 5), interpreted as the anterior and posterior pore imprints (afpi and pfpi); S-type ventral organisation (EVITT, 1985) with A/ai-arrangement.
Size. Small to intermediate, about 45 Ám to 50 Ám in diameter.
Remarks. This species is subdivided in two formae. The forma A (formerly "Gonyaulacysta sp. A" of DAVEY 1979; e. g. Pl. 3, fig. 1-9) includes specimens which are proximate, poorly ornamented, with low parasutural septa. The forma B (formerly "Gonyaulacysta sp. B" of DAVEY 1982; e. g. Pl. 5, fig. 1-9) accommodates specimens which are proximochorate, strongly ornamented, with high parasutural septa.
Dimensions
About 45 Ám to 50 Ám in diameter (20 specimens).
Remarks. The size range of Daveya boresphaera sp. nov. is remarkably consistent from one specimen to another, from one sample to another and from one well to another. Most of the measured specimens exhibit exactly the identical diameter of 50 Ám.
Stratigraphical and geographical distribution:
Until now, this species has mainly been reported from the European boreal province. DAVEY (1979, 1982) and COSTA & DAVEY (1992), reported Daveya boresphaera sp. nov. forma A (as "Gonyaulacysta sp. A") from the Late Ryazanian (Stenomphalus Ammonite Zone) of the British Isles and from the ?Early to Late Ryazanian of the Danish Haldager borehole No. 1. DAVEY (1982) reported Daveya boresphaera sp. nov. forma B (as "Gonyaulacysta sp. B") from the Late Ryazanian to Early Valanginian of Haldager borehole No 1. However, from our observations, and zonation/age discussion and modified ranges published in DAVEY (1982) and COSTA & DAVEY (1992) respectively, it appears that the total range of Daveya boresphaera sp. nov. is more likely restricted to the Late Ryazanian, and possibly to the Stenomphalus Ammonite Zone. DAVEY (1982) noted that this species is extremely rarely encountered in the North Sea Basin and occurs relatively infrequently in the Haldager No. 1 borehole. Offshore Mid-Norway, it is a relatively rare to common species, but always showing a consistent and significant range. Both formae occur together in samples dated as time equivalent to the Stenomphalus Ammonite Zone. This new taxa has never been reported from the Tethyan realm, but seems to occur in the Austral Province; DAVEY (1988) reported the presence of Daveya boresphaera forma A (as "Gonyaulacysta sp. A") in the Late Berriasian of Papua New Guinea.
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Holotype: Monteil 1996, Pl. 1, fig. 1-9; Pl. 2, fig. 1-9
Paratypes: Monteil 1996, Pl. 7, fig. 7-10 (Forma A), Pl. 5, fig. 1-9 (Forma B)
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Monteil 1996, p. 41-42
Daveya boresphaera sp. nov. (Pl. 1, fig. 1-9; Pl. 2, fig. 1-9; Pl. 3, fig. 1-9; Pl. 4, fig. 1-9; Pl. 5, fig. 1-9; Pl. 6, fig. 1-12; Pl. 7, fig. 1-10; Pl. 8, fig. 1-7; Fig. 2, 3, 4)
1979. Gonyaulacysta sp. A.- DAVEY, P. 61; pl. 4, fig. 6; text-fig. 5.
1982. Gonyaulacysta sp. A.- DAVEY, P. 29; pl. 10, fig. 3; fig. 3.
1982. Gonyaulacysta sp. B.- DAVEY, P. 29; fig. 3.
1988. Gonyaulacysta sp. A.- DAVEY, fig. 6.
1992. Gonyaulacysta sp. A.- COSTA & DAVEY, pl. 3.1, fig. 8; fig. 3.3.
Holotype: Pl. 1, fig. 1-9; Pl. 2, fig. 1-9. Slide 17.02 m /01, England Finder coordinates N32 (forma A/B).
Paratype 1: Pl. 5, fig. 1-9. Slide 17.02 m /01 England Finder coordinates F21 (forma B).
Paratype 2: Pl. 7, fig. 7-10. Slide 17.02 m /01, England Finder coordinates M 25/4 (forma A).
Type-locality: IKU core 82-7B (65¦ 05" 57.80" N; 10o 17" 34.10" E), Offshore Mid-Norway, Trondelag Platform, north-eastern Froan Basin.
Type-strata: Depth 17.02 m, Upper Ryazanian (Stenomphalus Ammonite Zone).
Diagnosis: (same as for the genus):
Shape. Typically spherical, with a very short apical horn, formed by linking of intratabular ornamentation and preapical/apical parasutures (Pl. 5, fig. 8, 9; Pl. 7, fig. 7-9; Pl. 8, fig. 7).
Wall relationships. Undifferentiated autophragm, thick and spongious; two appressed wall layers, pedium and luxuria, detectable using SEM (Pl. 8, fig. 6).
Wall features. Low parasutural septa (Pl. 7, fig. 7-10), rows of tubercles, bacula or pila (Pl. 3, fig. 1-9), or high parasutural septa proximally perforated and surmounted by long spines (Pl. 6, fig. 10-12; Pl. 8, fig. 2; Fig. 4); intratabular ornamentation tuberculate, baculate, pilate or echinate, with relief elements isolated (Pl. 6, fig. 4, 5) or distally linked (Pl. 3, fig. 2-5; Pl. 5, fig. 2).
Archeopyle. Precingular type P3..; operculum typically adherent.
Paratabulation. Clearly expressed by parasutural features; gonyaulacacean, formula: 2pr, Oa, 4", 6"", 6c, 6""", 1p, 1""""; ?ras, 2 fpi (Fig. 2, 3). Peculiarities: 4"/1" apical parasuture very clearIy marked (Pl. 1, fig. 1, 2; Pl. 2, fig. 1, 2; Pl. 4, fig. 1-7; Pl. 5, fig. 7-9; Pl. 7, fig. 9, 10); paraplate apical 4" in contact with the anterior extremity (as border) of parasulcus (A/ai-arrangement of HELENES, 1986; Pl. 7, fig. 2); paraplates 1""" very long, narrow, and completely delineated by parasutures, 2""" large, 1p small and very posteriorly situated (Pl. 1, fig. 1, 2; Pl. 2, fig. 1, 2; Pl. 5, fig. 5-6; Pl. 6, fig. 1-3, 10-11; Pl. 8, fig. 5); paraplate 4""" asymmetrical (Pl. 8, fig. 1).
Paracingulum. Indicated by six rectangular transversely elongate paraplates; laevorotatory.
Parasulcus. Indicated by bordering parasutural features and central depression, slightly sigmoidal; subdivision not discernible, except for the questionable ras (Pl. 8, fig. 5); flagellar pore imprint marked by two deeper depressions (Pl. 1, fig. 4; Pl. 2, fig. 4; Pl. 8, fig. 5), interpreted as the anterior and posterior pore imprints (afpi and pfpi); S-type ventral organisation (EVITT, 1985) with A/ai-arrangement.
Size. Small to intermediate, about 45 Ám to 50 Ám in diameter.
Remarks. This species is subdivided in two formae. The forma A (formerly "Gonyaulacysta sp. A" of DAVEY 1979; e. g. Pl. 3, fig. 1-9) includes specimens which are proximate, poorly ornamented, with low parasutural septa. The forma B (formerly "Gonyaulacysta sp. B" of DAVEY 1982; e. g. Pl. 5, fig. 1-9) accommodates specimens which are proximochorate, strongly ornamented, with high parasutural septa.
Dimensions
About 45 Ám to 50 Ám in diameter (20 specimens).
Remarks. The size range of Daveya boresphaera sp. nov. is remarkably consistent from one specimen to another, from one sample to another and from one well to another. Most of the measured specimens exhibit exactly the identical diameter of 50 Ám.
Stratigraphical and geographical distribution:
Until now, this species has mainly been reported from the European boreal province. DAVEY (1979, 1982) and COSTA & DAVEY (1992), reported Daveya boresphaera sp. nov. forma A (as "Gonyaulacysta sp. A") from the Late Ryazanian (Stenomphalus Ammonite Zone) of the British Isles and from the ?Early to Late Ryazanian of the Danish Haldager borehole No. 1. DAVEY (1982) reported Daveya boresphaera sp. nov. forma B (as "Gonyaulacysta sp. B") from the Late Ryazanian to Early Valanginian of Haldager borehole No 1. However, from our observations, and zonation/age discussion and modified ranges published in DAVEY (1982) and COSTA & DAVEY (1992) respectively, it appears that the total range of Daveya boresphaera sp. nov. is more likely restricted to the Late Ryazanian, and possibly to the Stenomphalus Ammonite Zone. DAVEY (1982) noted that this species is extremely rarely encountered in the North Sea Basin and occurs relatively infrequently in the Haldager No. 1 borehole. Offshore Mid-Norway, it is a relatively rare to common species, but always showing a consistent and significant range. Both formae occur together in samples dated as time equivalent to the Stenomphalus Ammonite Zone. This new taxa has never been reported from the Tethyan realm, but seems to occur in the Austral Province; DAVEY (1988) reported the presence of Daveya boresphaera forma A (as "Gonyaulacysta sp. A") in the Late Berriasian of Papua New Guinea.
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