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Xenascus wetzelii
From Fensome et al., 2019:
Xenascus wetzelii Slimani, 1996, p.380–381, pl.3, figs.F–G; pl.4, figs.A–B; text-figs.7A–B ex Slimani, 2001b, p.9, pl.2, figs.3–4,7–8.
Holotype: Slimani, 1996, pl.4, figs.A–B; Slimani, 2001b, pl.2, figs.3–4.
Taxonomic junior synonym: Odontochitina wetzelii (name not validly published), according to Slimani (2001a, p.194; 2001b, p.9). This name was not validly published in Slimani (1996) since no English or Latin description or diagnosis was provided.
Age: Campanian–early Maastrichtian (Campanian–?Maastrichtian according to Slimani, 1996, p.381).
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Original description Slimani 1996: Translation: PKB 2024
Xenascus wetzelii sp. nov.
(Fig. 7; Pl. 3, Fig. F,G; Pl. 4, Fig. A,B)
Derivation of the name. In honor of O. Wetzel who had worked on dinocysts from the Upper Cretaceous. from Germany.
Holotype. Beutenaken ech. 2, preparation 1, coordinate. E.F. E30/1; Pl. 4, Fig. A,B.
Paratype. Hallembaye ex. 12, preparation 1, coord. E.F. 046/3; Pl. 3, Fig. F.G.
Typical locality. Beutenaken ech. 2.
Typical horizon. Campanian.
Occurrence. Beutenaken: ex. 2 to 11 (late Campanian); Hallembaye: ex. 1 to 33 (Lower Campanian - Upper Campanian); Turnhout: -966.50 to -932 lm (upper Campanian).
1971 Odontochitina sp. Wilson: Pl. 2, Fig. 1, 2. ?1973 Odontochitina costata Alberti, 1961;
197 4 Odontochitina wetzelii sp. nov. in Wilson: p. 187, Pl. 7, Fig. 4-10, text-fig. 31.
1977 Odontochitina wetzelii Wilson, 1974 unpublished; Schumacker-Lambry in Streel et al. : Pl. 3, Fig. 8.
1985 Odontochitina wetzelii in Wilson, 1974; Foucher in Robaszynski et al. :Fig. 21, 22, Pl. 10, Fig. 9, 10, 11, 12.
? 1991 Odontochitina sp. A Kirsch: p. 46, Pl. 24, Fig. 7, 8.
1991 Odontochitina wetzelii in Wilson, 197 4; in Louwye: p. 206-207, Pl. 3, Fig. 14-15.
Description. Cornucavate to circumcavate cyst formed of an apical horn, an antapical horn and a straight postcingulate horn slightly longer than the antapical. The last two horns can communicate with each other. The wall consists of an endophragm and a periphragm closely attached to the central body which separate to form the horns. The microreticulated endophragm is much thicker (3 to 4 µm) than the periphragm. The thin, smooth and transparent periphragm develops low parasutural ridges on which more or less developed gonal processes are inserted. These processes of variable length (4 to 16 µm), solid or hollow, are pointed, bifurcated to trifurcated distally. There are sometimes small thorns distributed incidentally on the horns. The horns gradually become thinner towards their distal ends which are deteriorated and often bifurcated. The postcingulate horn often bears laterally at its base, a pointed or bifurcated gonal process on the anterior parasuture of the paracingulum. Paratabulation, sometimes incomplete, is indicated by parasutural ridges and gonal processes; the reconstructed paratabulation follows the corniform gonyaulacoid model; it consists of 4 apical paraplates, 6 precingulate
(2-1 i), X cingulates, 5 postcingulates (li-VI), X sulcals and apparently an antapical Y which forms with a posterior intercalary paraplate X the antapical horn. The well-defined postcingulate paraplate 1 i is subpentagonal. An apparently unsegmented paracingulum is marked by two low parasutural ridges which alternately bear gonal processes on either side. A parasulcus is very narrow and undifferentiated. The archaeopyle is apical with a free operculum.
Dimensions
Length of central body without cover: holotype, 50 µm; paratype, 56 µm; other specimens, 53-60 µm. Central body width: holotype, 54 µm; paratype, 54 µm; other specimens, 60-90 µm.
Lateral horn length: holotype, 54 µm; paratype, 60 µm; length of antapical horn: holotype, 66 µm; paratype, 84 µm; Antapical horn length: length of both horns in other specimens, 60-90 µm.
Process length: 4-16 µm.
Number of specimens measured: 8.
Remarks. The species corresponds well to Odontochitina wetzeliide Wilson (1974) unpublished and closely resembles other forms listed under the name Odontochitina wetzelii in Wilson (1974) by other authors cited above. Xenascus esbeckianus Yun (1981) has an endophragm that is more granular than reticulated and larger horns, one of which is an antapical and a postcingulate which communicate more clearly with each other. The new species is also distinguished from X. esbeckianus especially by its characteristic horns, most often bifurcated at their distal ends. We assigned the present species to the genus Xenascus and not to Odontochitina by referring to the emendation of Xanascus by Stover and Helby (1987: 128). Like other species of the genus Xenascus, our species has a periphragm which bears numerous processes, often hollow, divided or not distally and more prominent on gonal positions. In addition, it has a large cavation.
Stratigraphic and geographical distribution. Germany [Kirsch (1991): Lower Campanian. - Middle Campanian]; Belgium and the Netherlands [Wilson (1971, 1974): upper Campanian (B. mucronata zone), Foucher in Robaszynski et al., (1985): upper Campanian (B. mucronata zone) - lowerMaastrichtian (B. lanceolata zone)]; Belgium [Schumacker-Lambry in Streel et al. (1977) upper Campanian in Louwye (1991): Campanian]; Italy [Corradini (1973): Senonian]. The presence of this species in the lower Maastrichtian by Foucher in Robaszynski et al. (1985) is questionable.
Xenascus wetzelii Slimani, 1996, p.380–381, pl.3, figs.F–G; pl.4, figs.A–B; text-figs.7A–B ex Slimani, 2001b, p.9, pl.2, figs.3–4,7–8.
Holotype: Slimani, 1996, pl.4, figs.A–B; Slimani, 2001b, pl.2, figs.3–4.
Taxonomic junior synonym: Odontochitina wetzelii (name not validly published), according to Slimani (2001a, p.194; 2001b, p.9). This name was not validly published in Slimani (1996) since no English or Latin description or diagnosis was provided.
Age: Campanian–early Maastrichtian (Campanian–?Maastrichtian according to Slimani, 1996, p.381).
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Original description Slimani 1996: Translation: PKB 2024
Xenascus wetzelii sp. nov.
(Fig. 7; Pl. 3, Fig. F,G; Pl. 4, Fig. A,B)
Derivation of the name. In honor of O. Wetzel who had worked on dinocysts from the Upper Cretaceous. from Germany.
Holotype. Beutenaken ech. 2, preparation 1, coordinate. E.F. E30/1; Pl. 4, Fig. A,B.
Paratype. Hallembaye ex. 12, preparation 1, coord. E.F. 046/3; Pl. 3, Fig. F.G.
Typical locality. Beutenaken ech. 2.
Typical horizon. Campanian.
Occurrence. Beutenaken: ex. 2 to 11 (late Campanian); Hallembaye: ex. 1 to 33 (Lower Campanian - Upper Campanian); Turnhout: -966.50 to -932 lm (upper Campanian).
1971 Odontochitina sp. Wilson: Pl. 2, Fig. 1, 2. ?1973 Odontochitina costata Alberti, 1961;
197 4 Odontochitina wetzelii sp. nov. in Wilson: p. 187, Pl. 7, Fig. 4-10, text-fig. 31.
1977 Odontochitina wetzelii Wilson, 1974 unpublished; Schumacker-Lambry in Streel et al. : Pl. 3, Fig. 8.
1985 Odontochitina wetzelii in Wilson, 1974; Foucher in Robaszynski et al. :Fig. 21, 22, Pl. 10, Fig. 9, 10, 11, 12.
? 1991 Odontochitina sp. A Kirsch: p. 46, Pl. 24, Fig. 7, 8.
1991 Odontochitina wetzelii in Wilson, 197 4; in Louwye: p. 206-207, Pl. 3, Fig. 14-15.
Description. Cornucavate to circumcavate cyst formed of an apical horn, an antapical horn and a straight postcingulate horn slightly longer than the antapical. The last two horns can communicate with each other. The wall consists of an endophragm and a periphragm closely attached to the central body which separate to form the horns. The microreticulated endophragm is much thicker (3 to 4 µm) than the periphragm. The thin, smooth and transparent periphragm develops low parasutural ridges on which more or less developed gonal processes are inserted. These processes of variable length (4 to 16 µm), solid or hollow, are pointed, bifurcated to trifurcated distally. There are sometimes small thorns distributed incidentally on the horns. The horns gradually become thinner towards their distal ends which are deteriorated and often bifurcated. The postcingulate horn often bears laterally at its base, a pointed or bifurcated gonal process on the anterior parasuture of the paracingulum. Paratabulation, sometimes incomplete, is indicated by parasutural ridges and gonal processes; the reconstructed paratabulation follows the corniform gonyaulacoid model; it consists of 4 apical paraplates, 6 precingulate
(2-1 i), X cingulates, 5 postcingulates (li-VI), X sulcals and apparently an antapical Y which forms with a posterior intercalary paraplate X the antapical horn. The well-defined postcingulate paraplate 1 i is subpentagonal. An apparently unsegmented paracingulum is marked by two low parasutural ridges which alternately bear gonal processes on either side. A parasulcus is very narrow and undifferentiated. The archaeopyle is apical with a free operculum.
Dimensions
Length of central body without cover: holotype, 50 µm; paratype, 56 µm; other specimens, 53-60 µm. Central body width: holotype, 54 µm; paratype, 54 µm; other specimens, 60-90 µm.
Lateral horn length: holotype, 54 µm; paratype, 60 µm; length of antapical horn: holotype, 66 µm; paratype, 84 µm; Antapical horn length: length of both horns in other specimens, 60-90 µm.
Process length: 4-16 µm.
Number of specimens measured: 8.
Remarks. The species corresponds well to Odontochitina wetzeliide Wilson (1974) unpublished and closely resembles other forms listed under the name Odontochitina wetzelii in Wilson (1974) by other authors cited above. Xenascus esbeckianus Yun (1981) has an endophragm that is more granular than reticulated and larger horns, one of which is an antapical and a postcingulate which communicate more clearly with each other. The new species is also distinguished from X. esbeckianus especially by its characteristic horns, most often bifurcated at their distal ends. We assigned the present species to the genus Xenascus and not to Odontochitina by referring to the emendation of Xanascus by Stover and Helby (1987: 128). Like other species of the genus Xenascus, our species has a periphragm which bears numerous processes, often hollow, divided or not distally and more prominent on gonal positions. In addition, it has a large cavation.
Stratigraphic and geographical distribution. Germany [Kirsch (1991): Lower Campanian. - Middle Campanian]; Belgium and the Netherlands [Wilson (1971, 1974): upper Campanian (B. mucronata zone), Foucher in Robaszynski et al., (1985): upper Campanian (B. mucronata zone) - lowerMaastrichtian (B. lanceolata zone)]; Belgium [Schumacker-Lambry in Streel et al. (1977) upper Campanian in Louwye (1991): Campanian]; Italy [Corradini (1973): Senonian]. The presence of this species in the lower Maastrichtian by Foucher in Robaszynski et al. (1985) is questionable.