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Hystrichosphaeridium tubiferum ssp. ovale
From Fensome et al., 2019:
Hystrichosphaeridium tubiferum ssp. ovale Marheinecke, 1992, p.59–60, pl.10, figs.11,13–14. Holotype: Marheinecke, 1986, pl.6, figs.2– 3, as Hystrichosphaeridium tubiferum; Marheinecke, 1992, pl.10, figs.13–14; Fauconnier and Masure, 2004, pl.47, figs.8–10. Contrary to the opinion of Lentin and Williams (1993, p.337), Williams et al.
(1998, p.318) considered this name to be validly published. Age: early Maastrichtian.
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Original description: [Marheinecke, 1992] (translated from German):
Derivatio nominis: According to the ovaloidal shape of the central capsule.
Holotype: The specimen from preparation K885.2 shown in MARHEINECKE 1986 Plate 6, Figs. 2-3 and here Plate 10, Figs. 13+14 at 15.0/158.7.
Locus typicus: Former chalk pit Hemmoor (Lower Saxony).
Stratum typicum: Upper Lower Maastrichtian (Cimbric Zone), chalk.
Description: Cyst chorate, ovaloidal Wall composed of pedium and luxuria. The luxuria forms hollow tubiform intraareate processes, distally open with an aculeate, rounded margin. Accedation formula: NRpr/1pr, 4', 6", 6c, 5-6'", 1p, 1"", 4-5s. Archeopyle: apical, pr+1'+2'+3'+4', operculum secat, foederate (pr+1'+2'+3'+4'). The luxuria is usually alveolar and forms a foveolate tegillum between the processes. Forms with a compactly fused pedium/luxuria form a smooth surface. The apical, precingular, postcingular, antapic, and sulcal processes form round attachment scars. The cingular processes form oval scars. The terminal edge of the processes can range from aculeate to strongly frayed. While the cingulate processes are only slightly slender, the sulcal processes are considerably slender. A similarly slender pr-process was usually found on the opercula found in situ.
Additional note: In Hystrichosphaeridium tubiferum ssp. ovale, too, the forms with an alveolate tegillum predominate in the present material, which can also easily be interpreted as granulation in the LM.
Comparison: Hystrichosphaeridium tubiferum ssp. ovale differs from Hystrichosphaeridium tubiferum tubiferum in the shape of the central capsule, which is clearly ovaloid and not spheroidal. The processes are overall somewhat slimmer, which is particularly noticeable in the cingulate processes. Otherwise, the morphological similarity is great. However, since the distinguishing characters are consistently observed, differentiation at the ssp. level is feasible.
Specimens: >150
Statistics of the holotype: Length of central capsule: 50, width of central capsule: 37, length of processes: 35-38, diameter of processes at the narrowest point: approx. 2.5, at the cingulate processes: approx. 1.5, at the sulcal processes: approx. 1, archeopyle diameter: 27.
Statistics: Length of central capsule: 40(48)52, width of central capsule: 31(36)38, length of processes: 28-38, archeopyle diameter: 22-28.
Measured specimens: 12.
Known range: Maastrichtian
Hystrichosphaeridium tubiferum ssp. ovale Marheinecke, 1992, p.59–60, pl.10, figs.11,13–14. Holotype: Marheinecke, 1986, pl.6, figs.2– 3, as Hystrichosphaeridium tubiferum; Marheinecke, 1992, pl.10, figs.13–14; Fauconnier and Masure, 2004, pl.47, figs.8–10. Contrary to the opinion of Lentin and Williams (1993, p.337), Williams et al.
(1998, p.318) considered this name to be validly published. Age: early Maastrichtian.
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Original description: [Marheinecke, 1992] (translated from German):
Derivatio nominis: According to the ovaloidal shape of the central capsule.
Holotype: The specimen from preparation K885.2 shown in MARHEINECKE 1986 Plate 6, Figs. 2-3 and here Plate 10, Figs. 13+14 at 15.0/158.7.
Locus typicus: Former chalk pit Hemmoor (Lower Saxony).
Stratum typicum: Upper Lower Maastrichtian (Cimbric Zone), chalk.
Description: Cyst chorate, ovaloidal Wall composed of pedium and luxuria. The luxuria forms hollow tubiform intraareate processes, distally open with an aculeate, rounded margin. Accedation formula: NRpr/1pr, 4', 6", 6c, 5-6'", 1p, 1"", 4-5s. Archeopyle: apical, pr+1'+2'+3'+4', operculum secat, foederate (pr+1'+2'+3'+4'). The luxuria is usually alveolar and forms a foveolate tegillum between the processes. Forms with a compactly fused pedium/luxuria form a smooth surface. The apical, precingular, postcingular, antapic, and sulcal processes form round attachment scars. The cingular processes form oval scars. The terminal edge of the processes can range from aculeate to strongly frayed. While the cingulate processes are only slightly slender, the sulcal processes are considerably slender. A similarly slender pr-process was usually found on the opercula found in situ.
Additional note: In Hystrichosphaeridium tubiferum ssp. ovale, too, the forms with an alveolate tegillum predominate in the present material, which can also easily be interpreted as granulation in the LM.
Comparison: Hystrichosphaeridium tubiferum ssp. ovale differs from Hystrichosphaeridium tubiferum tubiferum in the shape of the central capsule, which is clearly ovaloid and not spheroidal. The processes are overall somewhat slimmer, which is particularly noticeable in the cingulate processes. Otherwise, the morphological similarity is great. However, since the distinguishing characters are consistently observed, differentiation at the ssp. level is feasible.
Specimens: >150
Statistics of the holotype: Length of central capsule: 50, width of central capsule: 37, length of processes: 35-38, diameter of processes at the narrowest point: approx. 2.5, at the cingulate processes: approx. 1.5, at the sulcal processes: approx. 1, archeopyle diameter: 27.
Statistics: Length of central capsule: 40(48)52, width of central capsule: 31(36)38, length of processes: 28-38, archeopyle diameter: 22-28.
Measured specimens: 12.
Known range: Maastrichtian