FIGURE 1. Map of Europe and Central Asia, illustrating the general distribution of representatives of the Belemnella kazimiroviensis group as a whole, without differentiation into particular species of the group. The origin of holotype specimens of representatives of this group recorded in the literature are as follows: Belemnella kazimiroviensis - Vistula section; Belemnella skolozdrownae - Stevns Klint; Belemnella pensaensis - Saratov/Penza; Belemnella arkhangelskii - Turgay Plateau.

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FIGURE 2. 1, location of the Middle Vistula River valley section in the Europe; 2, location in Poland together with the schematic extension of the Cretaceous and pre-Cretaceous deposits in Poland (without the Cenozoic cover); 3, position of Nasiłów along the Vistula River between the villages of Solec nad Wisłą and Kazimierz.

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FIGURE 3. 1, Generalised K-Pg section at Nasiłów; 2, Details of the boundary interval and the position of the K-Pg boundary placed at the top of the Kazimierz Opoka; according to Machalski (1998).

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FIGURE 4. 1, Schematic map of southern Limburg (the Netherlands) showing the formerly available outcrops of the Meerssen Member (red stars) (after Jagt et al., 1996) that yielded representatives of the Belemnella kazimiroviensis group; black dots are smaller towns in the area; 2, Position of the Netherlands within Europe (red star).

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FIGURE 5. Age, lithostratigraphy, general lithology and subdivision into lithostratigraphical horizons and units (IVe-1 to Va-4) of the section formerly exposed at the Curfs-Ankerpoort quarry (Geulhem), with indication (arrow) of the K-Pg boundary, equating with the Berg en Terblijt Horizon at the top of subunit IVf-6 (modified after Jagt and Jagt-Yazykova, 2012). The range of belemnite species shown is that for the entire Maastricht area. R = remanié specimens.

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FIGURE 6. Diagram illustrating morphological features of the belemnite guard (lateral view of a longitudinally split guard on the left, ventral view on the right). AA = alveolar angle; FA = fissure angle; SD = Schatzky distance; Ls = length from apex to protoconch; Ds, Dp, Dc = dorso-ventral diameters at different part of the rostrum; Bs, Bp, Bc = lateral diameters at different part of the rostrum (after Keutgen, 1997; Keutgen et al., 2012).

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FIGURE 7. Relative distribution of size groups of Bln. gr. kazimiroviensis from the glauconitic sandstone and basal Siwak at Nasiłów (Poland).

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FIGURE 8. Relative distribution of size groups of Bln. gr. kazimiroviensis from the Maastricht area - Geulhemmerberg underground section above the Berg en Terblijt Horizon (the Netherlands) and Albert Canal sections above the Vroenhoven Horizon (Belgium).

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FIGURE 9. Relationship of BI (Birkelund Index) vs Dp (dorso-ventral diameter at the protoconch) (BI = Ls/Dp; compare with Figure 6) of all guards of the kazimiroviensis group from the Middle Vistula River valley, the Maastricht area, Denmark, central and southern Russia and Central Asia, inclusive of data of early ontogenetic stages measured on longitudinally split specimens. The growth relationship is best described by a logarithmic curve, indicating that small (young) specimens are relatively more slender than larger (adult) ones.

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FIGURE 10. Two-dimensional plot Lsn (standardised length form apex to the protoconch) vs. AV (ventral aspect) of guards of Bln. kazimiroviensis and Bln. skolozdrownae from the Kazimierz Opoka (Kongiel Collection) from different localities (Kazimierz, Bochotnica and Nasilów), all except one from levels x and y sensu Pożaryski (1938).

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FIGURE 11. Two-dimensional plot for PC 1 and PC 2 derived from the PCA of belemnites of the kazimiroviensis group of the Kazimierz Opoka (Opoka) and the glauconitic sandstone (Greensand) of the Middle Vistula valley, as well as of those from the Maastricht area (the Netherlands, Belgium) (Meerssen).

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FIGURE 12. Two-dimensional plot Lsn (standardised length form apex to the protoconch) vs. AV (ventral aspect) of guards of Bln. kazimiroviensis and Bln. skolozdrownae from the glauconitic sandstone at Nasilów quarry. The dashed line indicates the variability of both species in the stratigraphically older Kazimierz Opoka.

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FIGURE 13. Two-dimensional plot Lsn (standardised length form apex to the protoconch) vs. AV (ventral aspect) of guards of Bln. kazimiroviensis from the basal Siwak at Nasilów quarry. The dashed lines indicate the variability of Bln. kazimiroviensis and Bln. skolozdrownae from the stratigraphically older glauconitic sandstone.

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FIGURE 14. Two-dimensional plot Lsn (standardised length form apex to the protoconch) vs. AV (ventral aspect) of guards of Bln. kazimiroviensis and Bln. skolozdrownae from deposits in the Maastricht area (the Netherlands, Belgium). The dashed lines indicate the variability of Bln. kazimiroviensis and Bln. skolozdrownae from the Middle Vistula valley region (Poland).

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FIGURE 15. Two-dimensional plot Lsn (standardised length form apex to the protoconch) vs. AV (ventral aspect) of guards of Bln. kazimiroviensis from central and southern Russia and Central Asia, as illustrated by Naidin (1975). The dashed lines indicate the variability of Bln. kazimiroviensis and Bln. skolozdrownae from the Maastricht and the Middle Vistula valley regions.

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FIGURE 16. Two-dimensional plot Lsn (standardised length form apex to the protoconch) vs. AV (ventral aspect) of guards of Bln. kazimiroviensis and Bln. skolozdrownae from Denmark mentioned in the scientific literature. The holotypes of Bln. kazimiroviensis, proposed by Jeletzky (1951) and Kongiel (1962), are also indicated (blank squares), in addition to the holotype of Bln. skolozdrownae from Denmark. The dashed lines indicate the variability of Bln. kazimiroviensis

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FIGURE 17. Belemnella (Neobelemnella) kazimiroviensis (Skołozdrówna, 1932). 1-4, NHMM JJ 4048/1, former Curfs-Ankerpoort quarry; basal Geulhem Member, Vroenhoven Horizon, + 0.00-0.05 m; 5-8, NHMM JJ 8339, former Blom quarry, Meerssen Member IVf-4; 9-12, NHMM MK 2516, Geulhemmerberg subterranean galleries near Geulhem, top of Meerssen Member (IVf-6); 13-16, MWGUW ZI/69/44, 17-20, ZI/69/47 and 21-24, ZI/69/51, respectively, from the "phosphatic layer" at Nasiłów quarry. All specimens are in natural size in following views: dorsal (1, 5, 9, 13, 17, 21), lateral (2, 6, 10, 14, 18, 22), longitudinally split specimen showing internal features (3, 7, 11, 15, 19, 23), and close-up of alveolar part [x2] with the course of the bottom of ventral fissure - dashed line (4, 8, 12, 16, 20, 24).

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FIGURE 18. Relationship of BI (Birkelund Index) vs Dp (dorso ventral diameter at the protoconch) (BI = Ls/Dp; compare with Figure 6) of guards of Bln. kazimiroviensis from the Middle Vistula valley and the Maastricht area. The growth relationship is best described by a logarithmic curve.

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FIGURE 19. Belemnella (Neobelemnella) skolozdrownae (Kongiel 1962). 1-4, NHMM MK 2815, Albert Canal near Vroenhoven (61F-19), uppermost Meerssen Member; 5-8, NHMM JJ 8759, ENCI-HeidelbergCement Group quarry, Maastricht, Meerssen Member, IVf-4 or IVf-5; 9-12, MWGUW ZI/69/70, and 13-16, ZI/69/86 - from the glauconitic sandstone below the "phosphatic layer" at Nasiłów; 17-20, MWGUW ZI/69/60 and 21-24, ZI/69/61 - from the "phosphatic layer" at Nasiłów quarry. All specimens are in natural size in following views: dorsal (1, 5, 9, 13, 17, 21), lateral (2, 6, 10, 14, 18, 22), longitudinally split specimen showing internal features (3, 7, 11, 15, 19, 23), and close-up of alveolar part [x2] with the course of the bottom of ventral fissure - dashed line (4, 8, 12, 16, 20, 24).

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FIGURE 20. Relationship of BI (Birkelund Index) vs Dp (dorso ventral diameter at the protoconch) (BI = Ls/Dp; compare with Figure 6) of guards of Bln. skolozdrownae from the Middle Vistula valley in Poland and the Maastricht area in the Dutch-Belgian border region, in addition to two specimens from Denmark (blank triangles) as illustrated in the scientific literature (Jeletzky, 1951, pl. 7, figure 1; Birkelund, 1957, pl. 6, figure 4).

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FIGURE 21. An excellently preserved specimen of Bln. kazimiroviensis (left) retaining part of the proostracum, together with a normally preserved guard (right) in the glauconitic sandstone at Nasiłów (field photograph; specimen with proostracum could not be collected completely).

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FIGURE 22. Estimation of percentage of belemnites of the kazimiroviensis group remaining in the habitat, calculated from size-group distribution at Nasiłów (Poland) and the Maastricht area (the Netherlands, Belgium).

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