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Subspecies Pachydiscus (Pachydiscus) neubergicus neubergicus Hauer 1858 | ||||||
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| Diagnosis / Definition: | ||||||
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Ward & Kennedy (1993): Description. - Biscay specimens up to 160 mm diameter. Coiling relatively involute with approximately two-thirds of previous whorl covered, whorls expanding at moderate rate. Umbilicus comprises around 30 percent of diameter, with low, rounded wall. All specimens crushed, and whorl section cannot be determined, although it seems to have been compressed, with rounded inner flanks, convergent outer flanks and rounded venter. Middle growth stages have 14-16 primary ribs per whorl. These arise at umbilical seam, sweep back, strengthen, and are concave on umbilical wall and develop into distant umbilical bullae. These are straight and prorsiradiate at smallest diameter seen, but become distinctly concave as size increases. Bullae extend across inner third of flanks, weakening, and passing into one or two ribs, which increase by branching and intercalation and sweep slightly forwards to cross venter in shallow convexity. There are from 20 to 27 ventral ribs per half whorl at this stage. As size increases, bullae weaken, and long primary ribs become more numerous, separated by single secondaries or not, ribbing weakening markedly over venter. |
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| Discussion / Comments: | ||||||
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Ward & Kennedy (1993): Type.- Lectotype is No. 1858.1.6 in the collections of the Austrian Geological Survey, the original of Hauer, 1858, p. 12, Pl. 2, figs. 1, 2, from Neuberg, Steiermark, Austria, designated by de Grossouvre, 1894, p. 209. Discussion.- Kennedy and Summesberger (1986) described and illustrated the lectotype (Figure 28.1-28.3) and a series of topotypes of Pachydiscus (P.) neubergicus neubergicus, and the Biscay material differs in no significant respects from their material. Henderson and McNamara (1985, p. 72, Pl. 7, figs. 7, 9, Pl. 10, figs. 3-6, text-figs. 1 1, 12c, 13c) described, as subspecies dissitus, a distinctive form from the upper Maastrichtian of western Australia. This has inner whorls like those of the nominate subspecies but the outer whorl, rather than having mainly primary ribs, has many more ventral than umbilical ribs, in this respect resembling P. (P.) gollevillensis (d'Orbigny, 1850) (p. 212; see Kennedy, 1986c, p. 28, Pls. 1-3, Pl. 4, figs. 4-6, Pl. 5, figs. 12-14,20-24, Pl. 11, figs. 1-5, text-figs. 2,3p, r, 4c). Indeed, Spath (1941, p. 45, Pl. 2, fig. 1) identified a fragment of P. (P.) neubergicus dissitus as Pachydiscus aff. gollevillensis. Differences between P. (P.) neubergicus neubergicus and other species are reviewed at length by Kennedy and Summesberger (1986) and are not discussed further here. When compared to other species in the Biscay fauna, P. (P.) gollevillensis (Figure 32) has 9-11 umbilical bullae and approximately 80 ribs per whorl, fewer bullae but more ribs than P. (P.) neubergicus neubergicus. Pachydiscus (P.) armenicus Atabekian and Akopian, 1969 (p. 8, Pl. 1, fig. 2, Pl. 3, figs. 1, 2; see Figure 34.1-34.6) in contrast has more (16-20) umbilical and ventral ribs (6 2-7 3). Pachydiscus (P.) jacquoti (Seunes, 1890b) (p. 5, Pl. 3(2), figs. 1-3) as revised by Kennedy (1986c, p. 34, Pl. 5, figs. 3-1 1, 15-19, Pl. 6, textfigs. 2d, e, 30, s, 4b) is easily separated. The whorls are lower, slowly expanding and subcircular when uncrushed, the shell having a wider umbilicus, with U in excess of 30 percent, few, distant primary ribs, and coarser, very distant ventral ornament. Pachydiscus (P.) epiplectus (Redtenbacher, 1873) (p. 12 1, Pl. 28, fig. 1) (Figure 28.4,28.5) and P. (P.) terminus sp. nov., described below, are both much more massive shells with dense ribbing. Occurrence. - In the Biscay sections this taxon ranges from low in Member I (lower Maastrichtian) to low in Member IV (upper Maastrichtian). Elsewhere, the nominate subspecies ranges from low in the lower Maastrichtian to low in the upper Maastrichtian, with records from Tercis, Landes, France, north Germany, Denmark, Austria, Poland, the Ukrainian SSR, Armenian SSR, European Russia, Nigeria, Zululand (South Africa), Madagascar, and south India. Subspecies dissitus is restricted to the upper Maastrichtian of western Australia. |
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| Systematics: | ||||||
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38 Ordo Ammonoidea Subordo Ammonitina Superfamilia Desmocerataceae Familia Pachydiscidae Genus Pachydiscus Subgenus Pachydiscus Subspecies Pachydiscus (Pachydiscus) neubergicus neubergicus 40 Ordo Ammonoidea Subordo Ammonitina Superfamilia Desmocerataceae Familia Pachydiscidae Genus Pachydiscus Subgenus Pachydiscus Subspecies Pachydiscus (Pachydiscus) neubergicus neubergicus |
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| Synonym list: | ||||||
| Ward & Kennedy (1993): p 1858 Ammonites Neubergicus Hauer. - Hauer : 12 pl. 2; fig. 1-3 [non pl. 3; fig. 1, 2]
1986 Pachydiscus (Pachydiscus) neubergicus Hauer. - Kennedy & Summesberger : p.189 pl. 2, fig. 1, 2;
pl. 3, fig. 1-3;
pl. 4, fig. 1-5;
pl. 5, fig. 1, 4, 5;
pl. 6, fig. 1, 2, 5;
pl. 15, fig. 7, 8;
text-fig. 5a, b (with full synonymy)
1986 Pachydiscus (Pachydiscus) neubergicus Hauer. - Kennedy : p.34 pl. 4; fig. 3
? 1988 Pachydiscus (Pachydiscus) cf. neubergicus Hauer. - Vasicek : p.76 pl. 1; fig. 3
1993 Pachydiscus (Pachydiscus) neubergicus neubergicus Hauer. - Ward & Kennedy : p. 27, 32, 33, 36 fig. 25.9, 25.10, 25.11, 25.12, 25.14, 25.16-25.18, 27.3-27.5, 27.7, 28.1-28.3, 30.4, 30.6
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| Was used in synonym list of: | ||||||
| Stratigraphy - relative ages: | ||||||
| upper Maastrichtian - lower Maastrichtian: Ward & Kennedy (1993) |
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| Specimen: | ||||||
| Collection of the Austrian Geological Survey, Inventory number: No. 1858.1.6 |
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| References: | ||||||
Hauer,F.. (1858): Kennedy,W.J.. (1986): Kennedy,W.J.. and Summesberger,H.. (1986): Vasicek,Z.. (1988): Ward,P.D.. and Kennedy,W.J.. (1993): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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