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Species Hoploscaphites tenuistriatus Kner 1848 | ||||||
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| Discussion / Comments: | ||||||
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Machalski (2005): TYPE MATERIAL.- The specimen from the lower upper Maastrichtian “Kreidemergel” of Kiselka, north of Lviv, illustrated by Kner (1848: pl. 1: 5) should be designated lectotype if still in existence (Kennedy 1987: 201) MATERIAL.- From Germany: three specimens from Hemmoor (NLfB kma 190–192) and two from Rügen (MGUH 20163, 20166). From the Ukraine: 16 specimens from Lviv (DPN NANU PZ−K−N5606, 9841a–c, 9842a–h, 9290, 9340–9342). From Denmark: four specimens from Ålborg, Jylland (MGUH 20160–20162, 20167). From Poland: a single specimen from Cheùm (ZPAL Am. 12/206). DISCUSSION.- Some confusion surrounds the type horizon and locality of this species. According to Kennedy and Sum− mesberger (1987), Kner’s specimen came from the lower lower Maastrichtian sandy opoka of Nagoryany, the Ukraine (Belemnella lanceolata and/or Bn. obtusa zones, see Chris− tensen 1987). In fact, this specimen is from locality Kiselka (Kner 1848), now being a part of Lviv near Wysoki Zamek (Julia Didenko, personal communication 2005), where the only Maastrichtian strata outcropping are the marls of the “Lvovskaja svita”. The type specimen of Hoploscaphites tenuistriatus is thus much younger than reported by Kennedy and Summesberger (1987), coming from strata correlating with the Spyridoceramus tegulatus–Belemnitella junior Zone as defined at Hemmoor. A sample of 24 adult macroconchs from the “Lvovskaja svita” of Lviv is available for the present study. Most of these are fragmentary or crushed. Thus, reliable measurements of maximum diameter could only be obtained from DPM NANU PZ−K−N9841a (47 mm) and DPM NANU PZ−K− N9340 (51 mm). The most distinctive feature of H. tenuistriatus is the rib− bing of the body chamber, which consists of fine, crowded, flexuous striae or riblets. The ribbing is dense although it var− ies rather widely. For example, the number of ribs on the last centimetre of the body chamber varies between 11 and 20 in a suite of six measurable specimens from Snopków brick− yard at Lviv, the Ukraine (DPM NANU PZ−K−N3182a–f). In contrast, the ribbing of the spire is coarse and does not differ from that seen in H. constrictus. Although some earlier authors (Nowak 1911; Birkelund 1979) mentioned specimens of H. tenuistriatus with tuber− cles, only non−tuberculate individuals (like those in Fig. 13A, C), have conventionally been assigned to this species by sub− sequent authors (Birkelund 1982, 1993; Kennedy 1987). There are three tuberculate specimens in the sample studied from Lviv: DPM NANU PZ−K−N5606, 9842a, and 9342 (the first specimen being the original of Nowak 1911: pl. 33: 14). These specimens are characterised by the presence of a rather narrow sector of diffused ribbing with three or four ventro− lateral tubercles near the base of the body chamber (e.g., Fig. 13B). A similar sector, with a faint trace of at least one tuber− cle visible, is present near the base of the otherwise densely ribbed and non−tuberculate body chamber in ZPAL Am. 12/206 from level II at Cheùm (Fig. 13D). Tuberculate individuals of Hoploscaphites with fine rib− bing on the body chamber were illustrated by Naidin (1974, pl. 58: 9) from the lower Maastrichtian of Crimea and by Nowak (1911: pl. 33: 11, 12, 14, 22) from the lower upper Maas− trichtian of Lviv. The latter material was tentatively assigned by Jeletzky (1962) to the North American Hoploscaphites nicolletii (Morton, 1842) (see Landman andWaage 1993a, for a revision). Jeletzky’s viewwas followed by Naidin (1974) for specimenDPMNANUPZ−K−N5606, which bears a strong re− semblance to H. nicolletii as seen in the photograph presented by Nowak (1911: pl. 33: 14; refigured by Naidin 1974: pl. 58: 13). Contrary to Jeletzky (1962) and Naidin (1974), Landman and Waage (1993a: 100) did not accept the occurrence of H. nicolletii in the Old World, arguing that the smaller umbilicus and the lack of a strong adapertural projection of the ribs and growth lines on the venter in the European specimens pre− cluded their conspecificity with H. nicolletii. This view is sup− ported here as a re−examination of the surviving fragment of specimen DPM NANU PZ−K−N5606 (Nowak 1911: pl. 33: 14) reveals that its ribbing, if corrected for post−mortem defor− mation, does not differ from that of other individuals of H. tenuistriatus from Lviv. In conclusion, the tuberculate specimens with dense, tenui− striatus−like ribbing on the body chamber are best interpreted as indigenous European scaphitids, morphologically interme− diate between H. constrictus and H. tenuistriatus. The latter species is best regarded as a short−ranging offshoot of the H. constrictus lineage. This is contra Birkelund (1967) and Coo− per (1994), who proposed a transition from H. greenlandicus Donovan, 1953 through H. tenuistriatus to H. constrictus. It is tempting to interpret “transitional” specimens as mem− bers of truly transitional populations between H. constrictus and H. tenuistriatus. However, the specimens from Lviv are late Maastrichtian in age and thus significantly postdate the first populations of H. tenuistriatus from Hemmoor (see Birkelund 1982: fig. 1), Denmark and the Isle of Rügen (Birkelund 1993) which are of early Maastrichtian age.More− over, tuberculate specimens with dense ribbing on the body chamber are separated by a distinct morphological gap from co−occurring H. constrictus lvivensis subsp. nov., at Lviv as well as at Cheùm. Accordingly, tuberculate specimens from these locations are interpreted as atypical end−members of H. tenuistriatus populations. The tuberculation preserved in these specimens is thought to be an atavistic feature, attesting to their evolutionary origin. The populations of Hoploscaphites constrictus truly ancestral to H. tenuistriatus should be sought in the upper lower Maastrichtian. The presence of a very finely ribbed, small individual of H. constrictus in the Belemnella sumensis Zone of Neuberg, Austria (Kennedy and Summes− berger 1986: pl. 16: 13) is worth mentioning in this respect. According to Radwañski (1996: 125), Hoploscaphites tenuistriatus “is very similar, if not identical” to H. melloi Landman and Waage, 1993a from the lower upper Maas− trichtian of the Western Interior, North America (see Kennedy et al. 1998: fig. 1 for a correlation of Western Interior ammo− nite zones with the standard subdivision of theMaastrichtian). Both taxa are indeed similar in ornament. However, H. tenui− striatus is characterised by a smaller umbilicus and taller body chamber than H. melloi. Moreover, it lacks the strong ad− apertural projection of the ventral ribs and growth lines, which is regarded to be a distinctive feature of the Western Interior Hoploscaphites lineage (Landman and Waage 1993a). Only macroconchs are present in the material studied and in most collections illustrated by other authors. A small indi− vidual from Hemmoor (NLfB kma 187) figured by Birkelund (1982: pl. 2: 5), interpreted by her as a microconch of Hoplo− scaphites constrictus or H. tenuistriatus, reveals numerous minute tubercles on the ventrolateral shoulder and is here as− signed to H. constrictus. The only possiblemicroconchs of the present species are the “Zwergexemplare” (dwarf specimens) of Hoploscaphites from the “Lvovskaja svita” at Lviv, illus− trated by Nowak (1911: pl. 33: 17, 18, 20, 21). As far as it can be discerned from the photographs in Nowak (1911), these specimens are non−tuberculate and finely ribbed on the near− apertural portions of their body chambers. STRATIGRAPHIC AND GEOGRAPHIC RANGE.- Upper lower Maas− trichtian and/or lower upper Maastrichtian of the Netherlands and Belgium (“Inoceramus” morgani Zone, Ireneusz Walasz− czyk and John W.M. Jagt, unpublished data), Germany (Belemnella sumensis to Spyridoceramus tegulatus–Belemni− tella junior zones), Denmark (Rugia tenuicostata–Meonia semiglobularis to Meonia semiglobularis–Ruegenella hum− boldtii zones), Poland (Spyridoceramus tegulatus–Belemni− tella junior Zone) and the Ukraine (Spyridoceramus tegu− latus–Belemnitella junior Zone). Less well−constrained re− cords are from the lower Maastrichtian of Isle of Rügen, the Czech Republic and southern Russia. |
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| Systematics: | ||||||
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51 Familia Scaphitidae Genus Hoploscaphites Species Hoploscaphites schmidi Species Hoploscaphites tenuistriatus |
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| Synonym list: | ||||||
| Machalski (2005): 1848 Scaphites n sp. tenuistriatus Kner. - Kner : p.10 pl. 1; fig. 5
1869 Scaphites tenuistriatus Kner. - Favre : p.21 pl. 5; fig. 6, 7
1911 Hoploscaphites constrictus-tenuistriatus Kner. - Nowak : p.585 pl. 33; fig. 13, 14
p 1911 Hoploscaphites constrictus vulgaris Nowak. - Nowak : p.586 pl. 33; fig. 11, 12 [non pl. 33; fig. 8-10 =
Hoploscaphites constrictus crassus] [nov. var.]
p 1911 Hoploscaphites constrictus vulgaris Nowak. - Nowak : p.586 pl. 33; fig. 17, 18, 20 [non fig. 15, 16 = Hoploscaphites constrictus;
non fig. 19 = Hoploscaphites sp. juv.] [nov. var.]
p 1911 Hoploscaphites constrictus-tenuistriatus Kner. - Nowak : p.586 pl. 33; fig. 21 [non fig. 22 = H. constrictus]
p 1932 Hoploscaphites constrictus Sowerby. - Wolansky : p.10 pl. 1; fig. 6 [Hoploscaphites constrictus var. tenuistriata in
figure caption] [non fig. 10 = Holposcaphites sp.
ex gr. pungens-schmidi; non fig. 11 =
Hoploscaphites constrictus]
1974 Hoploscaphites constrictus-tenuistriatus Kner. - Naidin : p.173 pl. 58, fig. 12;
pl. 60, fig. 5, 6
p 1974 Hoploscaphites constrictus constrictus Sowerby. - Naidin : p.173 pl. 58; fig. 9 [non fig. 7, 8 = Hoploscaphites constrictus]
1974 Hoploscaphites constrictus nicolletii Meek. - Naidin : p.174 pl. 58; fig. 13
1982 Hoploscaphites tenuistriatus Kner. - BIRKELUND : p.21 pl. 2; fig. 8-10
p 1987 Hoploscaphites tenuistriatus Kner. - Kennedy : p.201 pl. 31; fig. 2-3, 7 [non fig. 4-6 = Hoploscaphites sp. indet.]
1987 Hoploscaphites tenuistriatus Kner. - Kennedy & Summesberger : p.35 pl. 11; fig. 3
1987 Hoploscaphites constrictus-tenuistriatus Kner. - Tuuk : p.72 fig. 19
p 1993 Hoploscaphites tenuistriatus Kner. - BIRKELUND : p.59 pl. 14; fig. 8-11, 15, 16 [non fig. 13 = Hoploscaphites sp and non fig. 14
= Hoploscaphites felderi Kennedy, 1987]
2005 Hoploscaphites tenuistriatus Kner. - Machalski : p.672 fig. 13
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| Was used in synonym list of: | ||||||
| Stratigraphy - relative ages: | ||||||
| lower Maastrichtian - upper Maastrichtian: Machalski (2005) |
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| References: | ||||||
Kner,R.. (1848): Favre,E.. (1869): Nowak,K.. (1911): Wolansky,D.. (1932): Naidin,D.P.. (1974): BIRKELUND,T.. (1982): Kennedy,W.J.. (1987): Tuuk,V.V.L.. (1987): Kennedy,W.J.. and Summesberger,H.. (1987): BIRKELUND,T.. (1993): Machalski,M.. (2005): |
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| Anonymous: Unedited TaxonConcept data | ||||||
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