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Deflandrea cornumammillata
From Fensome et al., 2019:
Deflandrea cornumammillata Jan du Chêne and Châteauneuf, 1975, p.31–32, pl.2, figs.1–13. Holotype: Jan du Chêne and
Châteauneuf, 1975, pl.2, figs.7–8. Age: Early Eocene (early Ilerdian).
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Original description (Jan du Chêne and Chateauneuf, 1975) Translation PKB2025:
Holotype : Echantillon RJ C 1306, carriere de Boos, Gres des Voirons, Haute-Savoie, France (Jan du Chene, Gorin and van Stuijvenberg 1975), (fig.1 a, point A). (Pl. 2, fig. 7 et 8).
Origin of the name: with nipple-like (antapical) horns.
Diagnosis: Cavate cyst with an elongated periphragm, bilaterally symmetrical, and convex lateral margins. The apical horn is short, low, and rounded at the tip. The periphragm forms a sac in the antapical area. Both horns are reduced to small nipples at the lower angles of this sac. The periphragm is finely and regularly punctuated over its entire surface. The tabulation is not visible. The equatorial groove is poorly marked. The intercalary archaeopyle is trapezoidal with convex ribs. The endophragm is subcircular to ovoid, closely related to the periphragm in the cingulate area.
Dimensions (in μ): Holotype:
Periphragm:
Height: 90 μ.
Width: 66 μm.
Apical horn: 14 μm.
Height of the antapical sac: 10 μm.
Length of the antapical horns: 4 μm.
Capsule:
Height: 72 μm.
Dimensional variations (Number of specimens: 36):
Periphragm:
Height: 80 (94) 110 μm.
Width: 56 (70) 82 μm.
Apical horn: 8 (15) 24 μm.
Height of antapical sac: 6 (11) 20 μm.
Length of antapical horns: 4 to 6 μm.
1 specimen shows a 25 μm antapical horn (Pl. 2, Fig. 10).
Capsule:
Height: 50 (69) 82 μm.
The antapical horns are short and vary between 4 and 6 μ in length. One specimen shows a pointed antapical horn that reaches 25 μ (Pl. 2, fig. 10). By its general morphology, its sac-like periphragm and the position of the antapical horn at the lower angle of the periphragm, this specimen can however be related to Deflandrea cornumammillata. Observation by scanning electron microscopy allows to specify the description of this species: The periphragm is regularly punctuated over its entire surface. The endophragm is composed of two layers: the outer layer shows dense granulation over its entire surface (Pl. 2, figs. 11 to 13) ' the inner layer is regularly perforated. The equatorial furrow is sometimes distinguished. The tab is not visible.
Comparisons: The characteristic morphological elements of this species are the sac-like shape of the periphragm in the antapical zone and the reduced nipple-like shape of the antapical horns. By its general ovoid outline, Deflandrea cornumammillata n. sp. recalls D. eocenica BALTES 1969. This author also describes (1969, p. 34) D. hialina whose "antapical horns are joined and very vaguely delimited". Baltes (1969, pl. 1, fig. 3) shows a D. hialina with nipple-like antapical horns and resembling D. cornumammillata in this way. The dimensions of D. hialina, whose height varies from 55 to 60 μ, are however clearly inferior to those of D. cornumammillata, whose height reaches 80 to 110 μ. D. dakotaensis STANLEY 1965 differs from D. cornumammillata by its more pointed apical horn. ('terminated with a small solid papilla', Stanley 1965, p. 217) and its antapical horns which do not present the characteristic nipples of our species. D. pellucida DEFLANDRE and COOKSON 1955 has a pointed apical horn, a punctate periphragm, an archaeopyle higher and less wide than that of D. cornumammillata. D. micropoda COOKSON and EISENACK 1974 shows a smooth periphragm and endophragm and an archaeopyle in a very high position in the apical zone. This species has two small antapical cometas and in this character resembles D. cornumammillata.
Stratigraphic extension:
Holotype: Lower Ilerdian: Base of the Discoaster multiradiatus zone (Martini 1971). Bons quarry, Voirons sandstone, Haute-Savoie, France (Jan du Chene, Gorin, and van Stuijvenberg 1975).
Other specimens: The occurrence of Deflandrea cornumammillata corresponds to the base of the Wetzeliella homomorpha association defined in the Voirons sandstone (Jan du Chene, Gorin, and van Stuijvenberg 1975). D. cornumammillata is common in the Discoaster multiradiatus zone; it is rarer in the Marthasterites contortus zone.
Deflandrea cornumammillata Jan du Chêne and Châteauneuf, 1975, p.31–32, pl.2, figs.1–13. Holotype: Jan du Chêne and
Châteauneuf, 1975, pl.2, figs.7–8. Age: Early Eocene (early Ilerdian).
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Original description (Jan du Chêne and Chateauneuf, 1975) Translation PKB2025:
Holotype : Echantillon RJ C 1306, carriere de Boos, Gres des Voirons, Haute-Savoie, France (Jan du Chene, Gorin and van Stuijvenberg 1975), (fig.1 a, point A). (Pl. 2, fig. 7 et 8).
Origin of the name: with nipple-like (antapical) horns.
Diagnosis: Cavate cyst with an elongated periphragm, bilaterally symmetrical, and convex lateral margins. The apical horn is short, low, and rounded at the tip. The periphragm forms a sac in the antapical area. Both horns are reduced to small nipples at the lower angles of this sac. The periphragm is finely and regularly punctuated over its entire surface. The tabulation is not visible. The equatorial groove is poorly marked. The intercalary archaeopyle is trapezoidal with convex ribs. The endophragm is subcircular to ovoid, closely related to the periphragm in the cingulate area.
Dimensions (in μ): Holotype:
Periphragm:
Height: 90 μ.
Width: 66 μm.
Apical horn: 14 μm.
Height of the antapical sac: 10 μm.
Length of the antapical horns: 4 μm.
Capsule:
Height: 72 μm.
Dimensional variations (Number of specimens: 36):
Periphragm:
Height: 80 (94) 110 μm.
Width: 56 (70) 82 μm.
Apical horn: 8 (15) 24 μm.
Height of antapical sac: 6 (11) 20 μm.
Length of antapical horns: 4 to 6 μm.
1 specimen shows a 25 μm antapical horn (Pl. 2, Fig. 10).
Capsule:
Height: 50 (69) 82 μm.
The antapical horns are short and vary between 4 and 6 μ in length. One specimen shows a pointed antapical horn that reaches 25 μ (Pl. 2, fig. 10). By its general morphology, its sac-like periphragm and the position of the antapical horn at the lower angle of the periphragm, this specimen can however be related to Deflandrea cornumammillata. Observation by scanning electron microscopy allows to specify the description of this species: The periphragm is regularly punctuated over its entire surface. The endophragm is composed of two layers: the outer layer shows dense granulation over its entire surface (Pl. 2, figs. 11 to 13) ' the inner layer is regularly perforated. The equatorial furrow is sometimes distinguished. The tab is not visible.
Comparisons: The characteristic morphological elements of this species are the sac-like shape of the periphragm in the antapical zone and the reduced nipple-like shape of the antapical horns. By its general ovoid outline, Deflandrea cornumammillata n. sp. recalls D. eocenica BALTES 1969. This author also describes (1969, p. 34) D. hialina whose "antapical horns are joined and very vaguely delimited". Baltes (1969, pl. 1, fig. 3) shows a D. hialina with nipple-like antapical horns and resembling D. cornumammillata in this way. The dimensions of D. hialina, whose height varies from 55 to 60 μ, are however clearly inferior to those of D. cornumammillata, whose height reaches 80 to 110 μ. D. dakotaensis STANLEY 1965 differs from D. cornumammillata by its more pointed apical horn. ('terminated with a small solid papilla', Stanley 1965, p. 217) and its antapical horns which do not present the characteristic nipples of our species. D. pellucida DEFLANDRE and COOKSON 1955 has a pointed apical horn, a punctate periphragm, an archaeopyle higher and less wide than that of D. cornumammillata. D. micropoda COOKSON and EISENACK 1974 shows a smooth periphragm and endophragm and an archaeopyle in a very high position in the apical zone. This species has two small antapical cometas and in this character resembles D. cornumammillata.
Stratigraphic extension:
Holotype: Lower Ilerdian: Base of the Discoaster multiradiatus zone (Martini 1971). Bons quarry, Voirons sandstone, Haute-Savoie, France (Jan du Chene, Gorin, and van Stuijvenberg 1975).
Other specimens: The occurrence of Deflandrea cornumammillata corresponds to the base of the Wetzeliella homomorpha association defined in the Voirons sandstone (Jan du Chene, Gorin, and van Stuijvenberg 1975). D. cornumammillata is common in the Discoaster multiradiatus zone; it is rarer in the Marthasterites contortus zone.