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Species Hoploscaphites schmidi Birkelund 1982 | ||||||
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| Discussion / Comments: | ||||||
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Machalski (2005): TYPE MATERIAL.- Holotype is NLfB kma 181, a microconch from the lower upper Maastrichtian at Hemmoor, northern Germany (Birkelund 1982: 17, pl. 1: 7–9, refigured here as Fig. 16A1, A2). MATERIAL.- From Germany: 13 specimens from Hemmoor (NLfB kma 180–186, 204, 206, NLfB Ma 13570, 13571, plus two unregistered specimens). From Poland: five speci− mens from Che³m (ZPAL Am. 12/703, 704, 707, 717, 718). From Denmark: a single specimen, in four parts, from Hil− lerslev (MGUH 27744). DISCUSSION.- Prior to the present study, Hoploscaphites schmidi was known exclusively from the Hemmoor section. According to Birkelund (1982), the holotype, an adult micro− conch 46 mm in maximum diameter (Birkelund 1982: pl. 1: 7–9; Fig. 16A1, A2), was collected at 28.4 metres above the lower/upper Maastrichtian boundary clay bed M900 (T100). This level fallswithin the Belemnitella junior Zone (Birkelund 1982) and the lower part of the Tenuipteria argentea–Belem−nitella junior Zone (Schulz and Schmid 1983). The holotype was described in detail by Birkelund (1982). Only the pres− ence of two rows of tubercles on the whole of the exposed por− tion of the phragmocone (Figs. 16A1, A2, 17C) needs to be stressed herein, the ventrolaterals being much stronger than the laterals. Specimen NLfB kma 206 (Birkelund 1982: pl. 3: 12) is reinterpreted as another microconch of the species, because this fragment is indistinguishable from the corresponding part in the holotype (Jagt et al. 1999). This specimen comes from an unknown level above M900 (Birkelund 1982). The remainder of topotypical material represents macro− conchs (Birkelund 1982). This material shares the feeble ventral ribbing on the later part of the body chamber with the microconch holotype and is regarded to be conspecific be− yond doubt (Fig. 17C, D). The largest preserved macroconch fragment, NLfB kma 186 (Birkelund 1982: pl. 2: 4; Fig. 14A), suggests an individual c. 100 mm in maximum diame− ter. The presence of distinct ventral (siphonal) swellings on the early part of the shaft and their absence from the later part should be stressed; see Figs. 14A, 17D). The macroconch material from Hemmoor comes from the upper Spyridoceramus tegulatus–Belemnitella junior to lower Tenuipteria argentea–Belemnitella junior zones of Schulz and Schmid (1993). Amongst four unregistered NLfB specimens studied (e.g., Fig. 14E, F), a single specimen is from the base of the T. argentea–Bt. junior Zone, while the remaining individuals are either from below or above the lower/upper Maastrichtian boundary and lack additional provenance data. In summary, the material of H. schmidi from Hemmoor is averaged from an interval of 30–40 metres in minimum thickness. In spite of this, all specimens studied show a rather uniform style of ornament. Specimen NLfB kma 180, a spire with the initial part of the body chamber preserved, from the lower part of the T. argentea–Bt. junior Zone (Birkelund 1982: pl. 1: 6; Fig. 15A1, A2), is not Acanthoscaphites varians as claimed by Birkelund (1982). Its ornament is almost identical to that of a spire from Che³m (Fig. 15B1, B2) (specimen ZPAL Am. 12/707; see also Fig. 14G) with a morphology typical of H. schmidi as defined on Hemmoor material (compare Fig. 15A1, A2 and B1, B2). New material of Hoploscaphites schmidi, consisting of adult macroconchs, demonstrates the wider geographic range of this species. Five specimens are from the Spyridoceramus tegulatus–Belemnitella junior Zone at Che³m (levels III and IV) and a single specimen is from Hillerslev, Jylland (exact horizon unknown but the Hillerslev section spans the Rugia tenuicostata–Meonia semiglobularis to Meonia semiglobu− laris–Ruegenella humboldtii zones, see Surlyk 1984: fig. 3). The most complete specimen from Che³m is ZPAL Am. 12/707 from level III. This is an incomplete spire with a por− tion of the body chamber preserved (Figs. 14G, 15B1, B2). The ornament of the spire consists of rather coarse ribs which cross the venter and of two rows of tubercles. The ventrolaterals are much stronger than the bullate outer ventral tubercles. The flanks of the preserved portion of the body chamber are essen− tially smooth with traces of faint ribbing. The tuberculation of the body chamber consists of umbilicolateral and ventrolateral tubercles of similar strength. A less distinct row of ventral tu− bercles is also visible on the preserved part of the body cham− ber (Fig. 14G). This thus matches well the corresponding re− gion in specimen NLfB kma 186 (Birkelund 1982: pl. 2: 4; Fig. 14A). The remainder of the body chamber in ZPAL Am. 12/707 is broken off, except for the periumbilical area with well−developed umbilicolateral tubercles and weak ribs. This part of the Che³m specimen corresponds well to the corre− sponding portion in specimen NLfB kma 184 from Hemmoor (Birkelund 1982: pl. 2: 2). Other specimens from Che³mare shaft and hook fragments with preserved fine ventrolateral tubercules (but no ventral swellings) and relatively fine ribs crossing the venter (e.g., ZPAL Am. 12/703 in Fig. 14H). Size and style of ornament of these specimens is very similar to corresponding fragments from Hemmoor (Birkelund 1982: pl. 1: 10; pl. 2: 1, 3). Specimen MGUH 27744 from Hillerslev (Fig. 14C) is an external cast, in four parts, of the body chamber of a macro− conch, 90mmin maximum diameter. An early, smooth part of the body chamber with massive ventrolateral tuberculation is well visible and is similar to those in Polish and German speci− mens. Most of the flank area in the more adapertural part of the shaft is obliterated. Only the outer flank and venter are better seen. Fine and rather dense ventrolateral tubeculation on this part of the Hillerslev specimen matches well the German and Polish counterparts. However, the ribbing seems to be coarser and more regular (Fig. 14C). Most probably this reflects intrapopulation variation of the species. Wolansky’s specimen (1932: pl. 1: 11) is from an un− known level within the lower Maastrichtian of Rügen, and represents the basal portion of the body chamber of a fairly large specimen with two rows of massive tubercles and is reminiscent of corresponding parts in more complete speci− mens from Hemmoor and Che³m. A well−preserved specimen, ZPAL Am. 12/97, from Al− brychtówka (a hill between Podgórz and the town quarry near Kazimierz Dolny, Middle Vistula River section) is an adult microconch, 42 mm in maximum diameter (Fig. 16B). Al− though crushed, it resembles the holotype of Hoploscaphites schmidi in style of ornament and even shows incipient ventro− lateral tubercles in the early exposed part of the spire. Accord− ingly, ZPAL Am. 12/97 is referred to as Hoploscaphites schmidi?. An alternative interpretation is, however, that this specimen is an atypical end member of the population of Hoploscaphites constrictus crassus (£opuski, 1911). The specimen is from a significantly higher level than the material firmly assigned to H. schmidi, having been collected from the lower part of the Bn. kazimiroviensis Zone. According to Kennedy (1987) and Cooper (1994), H. schmidi and H. pungens are short−lived offshoots of the H. constrictus lineage. In this context it should be noted that the presence of ventrolateral tuberculation on the entire exposed spire of the holotype of H. schmidi recalls an analogous situ− ation in H. constrictus lvivensis subsp. nov. which occurs in coeval strata at Che³m. Thus, this member of the H. con− strictus lineage may have been ancestral to H. schmidi. STRATIGRAPHIC AND GEOGRAPHIC RANGE.- Upper lower and/or lower upper Maastrichtian of Germany (Spyridoceramus tegulatus–Belemnitella junior and Tenuipteria argentea– Belemnitella junior zones), Denmark (Rugia tenuicostata– Meonia semiglobularis Zone or Meonia semiglobularis– Ruegenella humboldtii Zone) and Poland (Spyridoceramus tegulatus–Belemnitella junior Zone). |
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| Systematics: | ||||||
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51 Familia Scaphitidae Genus Hoploscaphites Species Hoploscaphites constrictus Species Hoploscaphites schmidi |
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| Synonym list: | ||||||
| Machalski (2005): p 1932 Acanthoscaphites cf. tridens var. trinodosus Nowak. - Wolansky : p.10 pl. 1; fig. 11 [non pl. 2; fig. 4 =
Acanthoscaphites es gr. tridens]
? 1982 Acanthoscaphites schmidi Birkelund. - BIRKELUND : p.18 pl. 1, fig. 10;
pl. 2, fig. 1-4
sic! p 1982 Hoploscaphites constrictus Sowerby. - BIRKELUND : p.19 pl. 3; fig. 12 [non pl. 3; fig. 1-11, 13, 14 = Hoploscaphites
constrictus] [Sowerby, 1918 sic!]
p 1982 Acanthoscaphites varians Lopuski. - BIRKELUND : p.16 pl. 1; fig. 6 [non pl. 1, fig. 4 = Hoploscaphites sp. ex gr.
pungens-schmidi; non pl. 1, fig. 5 =
Acanthoscaphites (Euroscaphites) varians
blaszkiewiczi]
2005 Hoploscaphites schmidi Birkelund. - Machalski : p. 675, 676, 677, 67 fig. 14A, C, E-H, 15, 16A, 17C, D
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| Stratigraphy - relative ages: | ||||||
| upper Maastrichtian - lower Maastrichtian: Machalski (2005) |
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| References: | ||||||
Wolansky,D.. (1932): BIRKELUND,T.. (1982): Machalski,M.. (2005): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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