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Subspecies Acanthoscaphites (Euroscaphites) sp. verneuilianus d'Orbigny 1841 | ||||||
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| Discussion / Comments: | ||||||
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Machalski (2005): MATERIAL.- From Denmark: Three specimens from Rørdal (MGUH 20127, 20130, 27749) and a single specimen from Gudumholm (MGUH 27748). DISCUSSION.- A spire from Cotentin referred to as Acantho− scaphites sp. by Kennedy (1986: pl. 16: 7–10) closely resem− bles the holotype of A. (E.?) verneuilianus in ribbing up to di− ameter of 27 mm, but its later growth stages differ in that the primaries are separated by a single secondary rib only. As vir− tually nothing can be said on the range of variation of the “type population” of A. (E.?) verneuilianus, Kennedy’s (1986) spec− imen is best regarded as belonging to a separate taxon, allied to A. (E.?) verneuilianus. Amongst the specimens studied from Denmark, MGUH 20127 (Fig. 25B, also Birkelund 1993: pl. 8: 5; Jagt et al. 1999: pl. 8: 5),MGUH20130 (Birkelund 1993: pl. 10: 2; Jagt et al. 1999: pl. 8: 1), and MGUH 27749 (Fig. 25D) are from Rørdal, Jylland, from the upper lower Maastrichtian Rugia tenuicostata–Meonia semiglobularis Zone and/or lower up− per Maastrichtian Meonia semiglobularis–Ruegenella hum− boldtii Zone (Surlyk 1984: fig. 3). The fourth specimen, MGUH 27748 (Fig. 25A1, A2), is from Gudumholm, from the Meonia semiglobularis–Ruegenella humboldtii Zone (Surlyk 1984: fig. 3). All these specimens are spires that share the presence of narrow primary ribs, concave at the umbilical shoulder and straight or feebly flexuous, but al− ways prorsiradiate on the flanks. Up to four secondaries are intercalated between the primaries in MGUH 20127 (Fig. 25B) and in MGUH 27748 (Fig. 25A1, A2), and up to two in MGUH 27749 (Fig. 25D); the secondaries cannot be counted in MGUH 20130 (Birkelund 1993: pl. 10: 2; Jagt et al. 1999: pl. 8: 1) due to poor preservation of the specimen. Distinct siphonal tubercles are visible in MGUH 27748 (Fig. 25A1); they are barely visible in MGUH 20127. The well−developed ventrolateral tuberculation is present in three specimens il− lustrated (Fig. 25A, B, D) but cannot be seen in MGUH 20130 due to the incompleteness of the specimen. In addi− tion, outer ventrolaterals are visible in MGUH 20127 (Fig. 25B). Specimens MGUH 20127 and 20130 were interpreted by Jagt et al. (1999) as microconchs of Acanthoscaphites (E.) varians blaszkiewiczi. However, they differ significantly in style of ornament and number of tubercles from spires of com− parable size attributed to A. varians blaszkiewiczi (Fig. 25C, E) and are better interpreted as a separate taxon. In general, the ornament of the Danish material discussed above, although variably developed, recalls that of the holotype of A. (E.?) verneuilianus. However, the differences are such that the ma− terial studied is referred to as Acanthoscaphites (E.?) sp. aff. verneuilianus. Better−preserved specimens from Cotentin and Denmark are needed to clarify its taxonomic position. Mikhailov’s (1951) specimen from the “Maastrichtian” of Emba River and the specimen from the lower Maastrich− tian of Rügen figured by Reich and Frenzel (2002) seem to belong here as well, but poor preservation of the Emba speci− men and poor quality of the photograph of the Rügen speci− men, preclude any firm conlusions. Acanthoscaphites sp. of Kennedy and Christensen (1997: 124, fig. 40) from the upperMaastrichtian of southern Sweden seems to be unrelated, having a different ribbing which recalls that of Discoscaphites rossi Landman andWaage, 1993a from the upper Maastrichtian of the U.S. Western Interior (Land− man and Waage 1993a: 231, figs. 181–189). Here too, preser− vation is inadequate to allow firm conclusions. STRATIGRAPHIC AND GEOGRAPHIC RANGE.- Upper lower and/or lower upper Maastrichtian of Denmark (Rugia tenuicostata– Meonia semiglobularis Zone and/or Meonia semiglobularis– Ruegenella humboldtii Zone) and, possibly, of Germany and Russia. |
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| Systematics: | ||||||
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51 Species Acanthoscaphites (Euroscaphites) Subspecies Acanthoscaphites (Euroscaphites) sp. verneuilianus |
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| Synonym list: | ||||||
| Machalski (2005): ? 1951 Acanthoscaphites tridens var. varians Lopuski. - Mikhailov : p.104 pl. 16; fig. 72, 73
1986 Acanthoscaphites sp. . - Kennedy : p.74 pl. 16; fig. 7-10
p 1993 Acanthoscaphites varians Lopuski. - BIRKELUND : p.56 pl. 9, fig. 5;
pl. 10, fig. 2 [non pl. 9, fig. 3, 4, 6, 7;
pl. 10, fig. 3 = Acanthoscaphites (Euroscaphites)
varians blaszkiewiczi]
p 1999 Acanthoscaphites n spp. (Euroscaphites) varians blaszkiewiczi Jagt et al.. - Jagt et al. : p.139 pl. 8; fig. 1, 5 [only]
? 2002 Acanthoscaphites varians Lopuski. - Reich & Frenzel : pl. 23; fig. 1a, b
2005 Acanthoscaphites aff. ? (Euroscaphites) sp. verneuilianus d'Orbigny. - Machalski : p.687 fig. 25A, B, D
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| Stratigraphy - relative ages: | ||||||
| lower Maastrichtian - upper Maastrichtian: Machalski (2005) |
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| References: | ||||||
Mikhailov,N.P.. (1951): Kennedy,W.J.. (1986): BIRKELUND,T.. (1993): Jagt,W.J.M..; Kennedy,W.J.. and Machalski,M.. (1999): Reich,M.. and Frenzel,P.. (2002): Machalski,M.. (2005): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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Taxon relations
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