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Cauca maculosa
From Fensome et al., 2019:
Cauca maculosa Duxbury, 2018, p.179, pl.6, figs.9–10,13,16,19. Holotype: Duxbury, 2018, pl.6, fig.16. Age: early
Hauterivian.
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Original description Duxbury, 2018:
Type Locality: Well 20/01-10Z at 8943.10ft (conventional core chip), lower Hauterivian. Holotype: E.F. U37.4. Paratype: E.F. N25.1
Derivation of Name: From the Latin maculosus, dappled, spotted – in reference to the endophragm ornament of this species.
Diagnosis: A small, delicate species, ellipsoidal with the epicyst significantly shorter than the hypocyst. The epicyst is rounded triangular in outline and extends into a low apical prominence, terminating in an apical pore, and the hypocyst is semicircular.
The endophragm is entirely covered with regularly-spaced granules which are of variable size between specimens but of equal size per individual. The epicyst bears sutural crests suggesting a gonyaulacoid arrangement. Crests are low and bear flat, flexuous, bladelike projections of variable height between specimens. The archeopyle is epicystal, with the operculum usually attached.
Dimensions: Holotype (operculum attached): Central body – 41 × 35 µm. Overall: 51 × 51 µm.
Complete specimens: Central body – 46 (40) 33 µm × 38 (34) 30 µm. Overall: 76 (62) 51 µm × 71 (61) 48 µm. Specimens Measured: 20.
Remarks: This is a distinctive though delicate species, characterised by the presence of regularly-spaced granules covering the endocyst. It is closest to Cauca parva (Alberti 1961) Davey and Verdier 1971, a species also possessing an apical prominence, but without the endocystal ornament characteristic of C. maculosa n. sp. The endocystal granulation possibly reflects pore distribution in the motile stage.
In the present study, Cauca parva was observed as old as the early Valanginian, paratollia Zone, Bed D4A at Speeton, and it has been recorded throughout the Lower Cretaceous. In contrast, C. maculosa n. sp. appears to have a much more restricted range, largely within the basal Hauterivian, Subzone LKP10.3, and it is common in the upper part of its range.
Cauca maculosa Duxbury, 2018, p.179, pl.6, figs.9–10,13,16,19. Holotype: Duxbury, 2018, pl.6, fig.16. Age: early
Hauterivian.
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Original description Duxbury, 2018:
Type Locality: Well 20/01-10Z at 8943.10ft (conventional core chip), lower Hauterivian. Holotype: E.F. U37.4. Paratype: E.F. N25.1
Derivation of Name: From the Latin maculosus, dappled, spotted – in reference to the endophragm ornament of this species.
Diagnosis: A small, delicate species, ellipsoidal with the epicyst significantly shorter than the hypocyst. The epicyst is rounded triangular in outline and extends into a low apical prominence, terminating in an apical pore, and the hypocyst is semicircular.
The endophragm is entirely covered with regularly-spaced granules which are of variable size between specimens but of equal size per individual. The epicyst bears sutural crests suggesting a gonyaulacoid arrangement. Crests are low and bear flat, flexuous, bladelike projections of variable height between specimens. The archeopyle is epicystal, with the operculum usually attached.
Dimensions: Holotype (operculum attached): Central body – 41 × 35 µm. Overall: 51 × 51 µm.
Complete specimens: Central body – 46 (40) 33 µm × 38 (34) 30 µm. Overall: 76 (62) 51 µm × 71 (61) 48 µm. Specimens Measured: 20.
Remarks: This is a distinctive though delicate species, characterised by the presence of regularly-spaced granules covering the endocyst. It is closest to Cauca parva (Alberti 1961) Davey and Verdier 1971, a species also possessing an apical prominence, but without the endocystal ornament characteristic of C. maculosa n. sp. The endocystal granulation possibly reflects pore distribution in the motile stage.
In the present study, Cauca parva was observed as old as the early Valanginian, paratollia Zone, Bed D4A at Speeton, and it has been recorded throughout the Lower Cretaceous. In contrast, C. maculosa n. sp. appears to have a much more restricted range, largely within the basal Hauterivian, Subzone LKP10.3, and it is common in the upper part of its range.