Belemnella (Neobelemnella) skolozdrownae ( Kongiel, 1962 )

Keutgen, Norbert, Remin, Zbigniew & Jagt, John W. M., 2017, The late Maastrichtian Belemnella kazimiroviensis group (Cephalopoda, Coleoidea) in the Middle Vistula valley (Poland) and the Maastricht area (the Netherlands, Belgium) - taxonomy and palaeobiological implications, Palaeontologia Electronica 6 (3), pp. 1-29 : 21-23

Belemnella (Neobelemnella) skolozdrownae ( Kongiel, 1962)

Figure 19

1951 Belemnella casimirovensis (Skolozdrówna) var. skolozdrównae ; Jeletzky (pars), p. 119, pl. 7, figure 1 (non pl. 6 figure 4, pl. 7, figure 4).

1957 Belemnella casimirovensis casimirovensis ( Skolozdrówna, 1932) , 1951; Birkelund, p. 50, pl. 6, figure 4a-c.

1962 Belemnitella kazimiroviensis Skołozdrówna, 1932 ; Kongiel (pars), p. 35, pl. 5, figures 4-6 (non pl. 3, figures 7-9, pl. 4, figures 4-12, pl. 5, figures 1- 3, 7-12, pl. 6, figures 1-6).

1962 Belemnitella skolozdrównae ( Jeletzky, 1951) ; Kongiel, p. 36, pl. 6, figures 7-9 (non pl. 6, figures 10-12, pl. 7, figures 1-9).

Material. Two specimens (Mcd43/2, Mcd50/7)

from level "x" sensu Pożaryski (1938) of the Kazimierz Opoka from Bochotnica and Nasiłów,

respectively, in the Middle Vistula valley in Poland.

13 recently collected specimens from the Nasiłów quarry ( MWGUW ZI /69/01, 03, 65, 67, 69-70, 74,

79, 81-84, and 86) from the glauconitic sandstone below the "phosphatic layer" and six specimens

( MWGUW ZI /69/15, 18, 57, 60-61, 63) from the

"phosphatic layer". One specimen (Ma21= NHMM

JJ 8759) from subunit IVf-4 or IVf-5 of the Meerssen Member at the ENCI-HeidelbergCement

Group quarry, one specimen (Ma4 = NHMM MK

2815) from the uppermost Meerssen Member of and are not included in the calculation of the means.

locality 61F-19 at the Albert Canal, and one ( NHMM 2015 NK001-18) from immediately above the Vroenhoven Horizon at the Albert Canal near Vroenhoven.

Description. Specimens here referred to Bln. skolozdrownae are characterised by large fissure angles (FA> 70°), a slightly (occasionally distinctly) lanceolate shape in ventral (AV usually> 20%), and (usually) subcylindrical shape in lateral view (AL> -4%), in addition to a relatively slender guard (Lsn usually> 55 mm). Schatzky distances and alveolar angles are not different from representatives of Bln. kazimiroviensis ( Tables 4 and 5). Vascular markings and dorsolateral double furrows are well developed in well-preserved specimens. Longitudinal striae may be present and can result, in combination with the vascular markings, in a kind of pseudogranulation, especially in the anterior part of the guards. The apical end is frequently relatively acute, but may also be rounded with a less distinct mucro. The ontogenetic growth quotient of individual guards (WQs) could be calculated in a single specimen (MWGUW ZI/69/63) and accounted for 5.64.

Due to the limited number of specimens available of Bln. skolozdrownae , both guards illustrated by Jeletzky (1951) and Birkelund (1957) were added for the study of the relationship BI vs. Dp ( Figure 20 ). From the regression equation the "alternative WQs" for the interval between Dp1 = 5 mm and Dp2 = 14 mm was calculated. The corresponding value accounted for 4.47, i.e., distinctly larger than that of Bln. kazimiroviensis (3.33). The Lsn values of Bln. skolozdrownae can be calculated as follows:

Lsn = Dpn x BIn = 9.9 x (6.30 + (BI – (-1.997ln(Dp) + 10.879))) (in mm)

Discussion. Jeletzky (1951) recorded that the holotype of Bln. skolozdrownae was found c. 20 m below the K–Pg boundary at Stevns Klint. Thus, it is from the upper Sigerslev Member and stems from the zone with H. constrictus crassus . In consequence, the holotype of Bln. skolozdrownae is older than the material from Maastricht and stratigraphically related to specimens from the Kazimierz Opoka in the central Vistula River valley.

Distribution. Belemnella skolozdrownae is recorded from the upper upper Maastrichtian Sigerslev Member in Denmark (upper part of the zone with H. constrictus crassus ) and from about the same level in Poland (Kazimierz Opoka). In the Maastricht area it ranges into the upper Meerssen Member up to the end of the Maastrichtian Stage (IVf-4 to IVf-6), including the zone with H. constrictus johnjagti .

Figures

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).

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).