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Pyxidinopsis psilata form quadrata
Pyxidinopsis sp. 1 of Rochon et al., 2002.
Holotype: Plate A-I, fig. 15, Mudie et al., 2024b n.fa.
Locality: ˙Imralı Basin, Marmara Sea, core M02–88P, sample 210 cm.
Stratum: Holocene.
Etymology: quadrata = square-shaped (Latin).
Additional Material: Mudie et al. (2017, plate-figs. 10–12), as morphotypes of Pyxidinopsis psilata.
Diagnosis: Pyxidinopsis psilata form quadrata is a morphotype of P. psilata characterised by a quadriform ambitus and coarsely granulate to rugulate wall surface (Plate A-I, 15–20). The ambitus shape is typically evenly 4-lobed as in a 3-dimensional “plus” (+) sign, not crucifix shaped like a Ŧ as in Spiniferites cruciformis. The cyst is sphaeroidal, without the dorsoventral flattening characteristic of S. cruciformis. However, the equatorial lobes are frequently unevenly enlarged or contorted (Plate A-I, 17–20), and multi-lobate ambitus shapes were seen in core M98–4 (Plate A-I, Fig. 12) and referred to as Pyxidinopsis sp. 1 in Rochon et al., 2002).
Comparison: Pyxidinopsis? sp. A of Londeix in Londeix et al. (2009), their pl. III, figs. 3, 4; also Plate A-I, Figs. 9, 10) has a comparable sub-cruciform rhomboidal shape and rugulate periphragm, and the lobe variation observed in specimens of P. psilata f. quadrata from ˙Imralı Basin Propontis Lake and Neoeuxine Lake core Atlantis 1474 probably overlaps that of the deep-water lacustrine-phase Lake populations studied by Londeix et al. (2009). Hence, the taxa were grouped for counts in this study. Mudie et al. (2017, plate-fig. 11) illustrate a modern Caspian Sea specimen with an apical node.
Holotype: Plate A-I, fig. 15, Mudie et al., 2024b n.fa.
Locality: ˙Imralı Basin, Marmara Sea, core M02–88P, sample 210 cm.
Stratum: Holocene.
Etymology: quadrata = square-shaped (Latin).
Additional Material: Mudie et al. (2017, plate-figs. 10–12), as morphotypes of Pyxidinopsis psilata.
Diagnosis: Pyxidinopsis psilata form quadrata is a morphotype of P. psilata characterised by a quadriform ambitus and coarsely granulate to rugulate wall surface (Plate A-I, 15–20). The ambitus shape is typically evenly 4-lobed as in a 3-dimensional “plus” (+) sign, not crucifix shaped like a Ŧ as in Spiniferites cruciformis. The cyst is sphaeroidal, without the dorsoventral flattening characteristic of S. cruciformis. However, the equatorial lobes are frequently unevenly enlarged or contorted (Plate A-I, 17–20), and multi-lobate ambitus shapes were seen in core M98–4 (Plate A-I, Fig. 12) and referred to as Pyxidinopsis sp. 1 in Rochon et al., 2002).
Comparison: Pyxidinopsis? sp. A of Londeix in Londeix et al. (2009), their pl. III, figs. 3, 4; also Plate A-I, Figs. 9, 10) has a comparable sub-cruciform rhomboidal shape and rugulate periphragm, and the lobe variation observed in specimens of P. psilata f. quadrata from ˙Imralı Basin Propontis Lake and Neoeuxine Lake core Atlantis 1474 probably overlaps that of the deep-water lacustrine-phase Lake populations studied by Londeix et al. (2009). Hence, the taxa were grouped for counts in this study. Mudie et al. (2017, plate-fig. 11) illustrate a modern Caspian Sea specimen with an apical node.