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Ellipsoidictyum imperfectum subsp. prolatum
From Fensome et al., 2019:
Ellipsoidictyum imperfectum subsp. prolatum Duxbury, 2001, p.106–107, fig.8, nos.1–3. Holotype: Duxbury, 2001, fig.8, nos.2. Age: late Aptian–early Albian.
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Original description (Duxbury, 2001):
Ellipsoidictyum imperfectum (BRIDEAUX & MCINTYRE, 1975) LENTIN & WILLIAMS, 1977 subsp. prolatum n. subsp.
Holotype: Figure 8.2.
Type Locality: Well 13/24-1 at 4820 ft (ditch cuttings), Early Albian, E.F. S48.4.
Derivation of name: From the Latin prolatus, extended, elongated, releming
to the elongate nature of this sub-species.
Diagnosis: An elongate ellipsoidal dinocyst, which is single-layered and fairly thick-walled. The smooth to very finely punctate cyst wall usually
bears low ornament consisting of individual spines or baculae which may be laterally connected. The surface ornament can outline a vestigial paratabulation, although a complete paratabulation pattern has not been observed. In rare cases, the cyst wall appears to be devoid of ornament. The archeopyle is tetratabular apical; the operculum may be lost, but it is commonly attached.
Dimensions: Holotype (operculum attached): 82 x 58 μm
Overall (operculum attached): 87 (74) 63 x 66 (59) 52 μm
Specimens Measured – 10
Overall (operculum detached): 68 (66) 60 x 57 (56) 52 μm
Specimens Measured - 7
Comments: The overall characteristics of this taxon are very reminiscent of Ellipsoidictyunm imperfectum (BRIDEAUX & McINTYRE, 1975) LENTIN & WILLIAMS, 1977, and common to abundant occurrences of E. imperfectum, as described by BRIDEAUX & McINTYRE (Op. cit.) are often associated with it. However, the elongate nature of E. imperfectum subsp. prolatum and its consistently very reduced surface ornament set it apart from the essentially circular to oval forms of BRIDEAUX & McINTYRE (op.cit.). This subspecies is essentially an Early Albian and Late Aptian form, and a major influx is a key marker within the earliest Albian, Tardefurcata Ammonite Zone in the study area.
Ellipsoidictyum imperfectum subsp. prolatum Duxbury, 2001, p.106–107, fig.8, nos.1–3. Holotype: Duxbury, 2001, fig.8, nos.2. Age: late Aptian–early Albian.
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Original description (Duxbury, 2001):
Ellipsoidictyum imperfectum (BRIDEAUX & MCINTYRE, 1975) LENTIN & WILLIAMS, 1977 subsp. prolatum n. subsp.
Holotype: Figure 8.2.
Type Locality: Well 13/24-1 at 4820 ft (ditch cuttings), Early Albian, E.F. S48.4.
Derivation of name: From the Latin prolatus, extended, elongated, releming
to the elongate nature of this sub-species.
Diagnosis: An elongate ellipsoidal dinocyst, which is single-layered and fairly thick-walled. The smooth to very finely punctate cyst wall usually
bears low ornament consisting of individual spines or baculae which may be laterally connected. The surface ornament can outline a vestigial paratabulation, although a complete paratabulation pattern has not been observed. In rare cases, the cyst wall appears to be devoid of ornament. The archeopyle is tetratabular apical; the operculum may be lost, but it is commonly attached.
Dimensions: Holotype (operculum attached): 82 x 58 μm
Overall (operculum attached): 87 (74) 63 x 66 (59) 52 μm
Specimens Measured – 10
Overall (operculum detached): 68 (66) 60 x 57 (56) 52 μm
Specimens Measured - 7
Comments: The overall characteristics of this taxon are very reminiscent of Ellipsoidictyunm imperfectum (BRIDEAUX & McINTYRE, 1975) LENTIN & WILLIAMS, 1977, and common to abundant occurrences of E. imperfectum, as described by BRIDEAUX & McINTYRE (Op. cit.) are often associated with it. However, the elongate nature of E. imperfectum subsp. prolatum and its consistently very reduced surface ornament set it apart from the essentially circular to oval forms of BRIDEAUX & McINTYRE (op.cit.). This subspecies is essentially an Early Albian and Late Aptian form, and a major influx is a key marker within the earliest Albian, Tardefurcata Ammonite Zone in the study area.