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Wrevittia diutina ssp. patula
Plate 21, Figures 6, 7, 10-14, 17-19
Holotype: Plate 21, Figure 13, 14.
Paratype: Plate 21, Figures 10-12.
Type Locality: Speeton Clay Formation, early Hauterivian, amblygonium ammonite Zone. Holotype: Slide D2B(1), E.F. O63.3. Paratype: Slide D2A(3), E.F. J36.4.
Derivation of Name: From the Latin patulus, spread out, broad, wide - in reference to the pterocavation demonstrated by this subspecies.
Diagnosis: A fairly thick-walled subspecies of intermediate size, smooth and with prominent intratabular baculae and/or coni. A short apical horn is invariably present, displaying moderate cornucavation. Tabulation of the formula 4', 6'', ?c, 6''', 1p, 1p.v., 1'''' is marked by denticulate crests. Ventral displacement of a prominent cingulum exceeds one cingulum-width. Pterocavation is variously developed, producing a rounded ovoidal to subcircular outline in lateral aspect. The archeopyle is single-plate precingular (3").
Dimensions: Holotype: Length - 56 μm. Width - 51 μm.
Paratype: Length - 51 μm. Width - 53 μm.
Overall: 63 (56) 51 μm × 63 (52) 46 μm.
Specimens Measured: 5.
Remarks: This subspecies is typical of Wrevittia diutina, but is distinguished from other subspecies by its pterocavation. Occurrences of W. diutina subsp. patula were restricted in the present study to the oldest early Hauterivian, Speeton Beds D2D to D1, amblygoniun to noricum ammonite Zones.
Holotype: Plate 21, Figure 13, 14.
Paratype: Plate 21, Figures 10-12.
Type Locality: Speeton Clay Formation, early Hauterivian, amblygonium ammonite Zone. Holotype: Slide D2B(1), E.F. O63.3. Paratype: Slide D2A(3), E.F. J36.4.
Derivation of Name: From the Latin patulus, spread out, broad, wide - in reference to the pterocavation demonstrated by this subspecies.
Diagnosis: A fairly thick-walled subspecies of intermediate size, smooth and with prominent intratabular baculae and/or coni. A short apical horn is invariably present, displaying moderate cornucavation. Tabulation of the formula 4', 6'', ?c, 6''', 1p, 1p.v., 1'''' is marked by denticulate crests. Ventral displacement of a prominent cingulum exceeds one cingulum-width. Pterocavation is variously developed, producing a rounded ovoidal to subcircular outline in lateral aspect. The archeopyle is single-plate precingular (3").
Dimensions: Holotype: Length - 56 μm. Width - 51 μm.
Paratype: Length - 51 μm. Width - 53 μm.
Overall: 63 (56) 51 μm × 63 (52) 46 μm.
Specimens Measured: 5.
Remarks: This subspecies is typical of Wrevittia diutina, but is distinguished from other subspecies by its pterocavation. Occurrences of W. diutina subsp. patula were restricted in the present study to the oldest early Hauterivian, Speeton Beds D2D to D1, amblygoniun to noricum ammonite Zones.