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Downiesphaeridium chems
Original description (Below, 1982c) Translation PKB 2025
Diagnosis: Two-layered, scolochorate cyst. Central body spheroidal. Surface smooth, covered by 100-150 appendages. These are evenly distributed over the body. The appendages are hollow, closed proximally and distally. They taper continuously from their base to a point, or sometimes end oblately or bifidly. An archaeopyle of type A is rarely formed.
Comparison: This species differs from Polysphaeridium flexuosum (Davey, Downie, Sarjeant & Williams 1966) comb. nov. in its smooth surface.
Dimensions: Holotype: Diameter of the central body 28 µ, length of the appendages 11 µ, diameter of the appendages 2 µ; other specimens: diameter of the central body 36-41 µ, length of the appendages 9-13 µ, diameter of the appendages 2 µ.
Material: 16 specimens.
Occurrence: Profile EB (19): Hauterivian
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Polysphaeridium chems BELOW 1982c, p. 27–28, pl. 2, figs. 8a–b; textfig. 6b.
Holotype: Below 1982c, pl. 2, figs. 8a–b. – FAUCONNIER and MASURE 2004, pl. 19, figs. 12, 13.
Dapsilidinium chems (Below 1982c). – LENTIN and WILLIAMS 1985, p. 91.
Remarks: As described by Below (1982c, p. 27), this is a smooth, spheroidal species bearing numerous, distally-closed, hollow processes which taper and may be bifid. It was recorded in the present study between Vergol Bed V68M (early Valanginian, neocomiensiformis Zone, neocomiensiformis Sub-zone) and the top of the studied La Charce section. It was particularly common in Vergol Bed 88 (Barrande layer B4), again within the early Valanginian. The Valanginian occurrences recorded here extend the range of this species below the Hauterivian as quoted by Below (op. cit., p. 28 and fig. 14).
In overall morphology, Downiesphaeridium chems resembles D. flexuosum but in the present study it tends to be smaller (see pl. 13, figs. 16, 17). As highlighted by Below (1982c, p. 28), the cyst wall is smooth, as opposed to the microgranular to microspinose ("chagrinat" in Below op. cit., p. 29) main body ornament observed in D. flexuosum.
Diagnosis: Two-layered, scolochorate cyst. Central body spheroidal. Surface smooth, covered by 100-150 appendages. These are evenly distributed over the body. The appendages are hollow, closed proximally and distally. They taper continuously from their base to a point, or sometimes end oblately or bifidly. An archaeopyle of type A is rarely formed.
Comparison: This species differs from Polysphaeridium flexuosum (Davey, Downie, Sarjeant & Williams 1966) comb. nov. in its smooth surface.
Dimensions: Holotype: Diameter of the central body 28 µ, length of the appendages 11 µ, diameter of the appendages 2 µ; other specimens: diameter of the central body 36-41 µ, length of the appendages 9-13 µ, diameter of the appendages 2 µ.
Material: 16 specimens.
Occurrence: Profile EB (19): Hauterivian
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Polysphaeridium chems BELOW 1982c, p. 27–28, pl. 2, figs. 8a–b; textfig. 6b.
Holotype: Below 1982c, pl. 2, figs. 8a–b. – FAUCONNIER and MASURE 2004, pl. 19, figs. 12, 13.
Dapsilidinium chems (Below 1982c). – LENTIN and WILLIAMS 1985, p. 91.
Remarks: As described by Below (1982c, p. 27), this is a smooth, spheroidal species bearing numerous, distally-closed, hollow processes which taper and may be bifid. It was recorded in the present study between Vergol Bed V68M (early Valanginian, neocomiensiformis Zone, neocomiensiformis Sub-zone) and the top of the studied La Charce section. It was particularly common in Vergol Bed 88 (Barrande layer B4), again within the early Valanginian. The Valanginian occurrences recorded here extend the range of this species below the Hauterivian as quoted by Below (op. cit., p. 28 and fig. 14).
In overall morphology, Downiesphaeridium chems resembles D. flexuosum but in the present study it tends to be smaller (see pl. 13, figs. 16, 17). As highlighted by Below (1982c, p. 28), the cyst wall is smooth, as opposed to the microgranular to microspinose ("chagrinat" in Below op. cit., p. 29) main body ornament observed in D. flexuosum.