Haedropleura sp.

Scarponi, Daniele, Bella, Giano Della, Dell’Angelo, Bruno, Huntley, John Warren & Sosso, Maurizio, 2016, Middle Miocene conoidean gastropods from western Ukraine (Paratethys): Integrative taxonomy, palaeoclimatogical and palaeobiogeographical implications, Acta Palaeontologica Polonica 61 (2), pp. 327-344 : 341

Haedropleura sp. aff. H. septangularis ( Montagu, 1803)

Figs. 7F , 8I, J ; SOM 1: fig. 3K, SOM 2.

Material.— Eleven specimens from Varovtsi, Pidhirtsi Beds, early Serravallian; MGGC-23525 /1–11, of which only three are in fair/good conditions (SOM 2) .

Remarks. — Our specimens show affinity with Haedropleura septangularis , a Recent Mediterranean and East Atlantic species also cited in the “Helvetian” of the Loire Basin ( Glibert 1954; this material needs further investigation), Pliocene of England ( Harmer 1915) and Plio–Pleistocene of the Mediterranean ( Scarponi et al. 2011b). The two taxa present comparable juvenile development and similar teleoconch morphology (see Scarponi et al. 2011b; SOM 1: fig. 4L, M, SOM 2). However, Ukranian specimens relative to H. septangularis show a smaller teleoconch (and shorter last whorl and aperture; Fig. 2 , SOM 2). Also statistical tests do not support equality of the targeted teleoconch parameters between the two taxa ( Table 1, SOM 3). However, the extremely small sample size for all protoconch and sculpture features of Haedropleura sp. (i.e., only 2−4 observations; Table 1, SOM 3), suggest caution and additional, well preserved, material is needed to reach more reliable conclusions. Also, Haedropleura pseudoseptangularis Gürs, 2001 , seems to be another related (but distinct) species. Unfortunately, H. pseudoseptangularis is rarely found ( Tucker 2004), and its intra-specific variability, at the moment, cannot be assessed. Indeed, only one specimen has been described from the upper Miocene (~14.5 Ma) of the North Sea Basin. We refer to Gürs (2001) for illustration and description of the only known specimen. In conclusion, our morphotype presents certain protoconch and teleoconch features akin to H. septangularis whereas the teleoconch sculpture (especially rib morphology), and final whorl resemble H. pseudoseptangularis ( Gürs 2001) . Unfortunately the small number of well-preserved specimens from Varovtsi (SOM 2) is considered insufficient to assess the variability of this taxon; therefore its taxonomic position is left open.

Figures

Fig. 7. SEM images of protoconch features of conoidean gastropods from early Serravallian of western Ukraine, Varovtsi (A, C–F) and Horodok (B). A. Bela? robusta sp. nov., MGGC-24519/8. B. Pyrgocythara turrispiralata sp. nov., MGGC-24515/11. C. Raphitoma cf. R. ringicula (Boettger, 1902), MGGC-24522/5. D. Andonia sp. aff. A. transsylvanica (Hoernes and Auinger, 1890), MGGC 24523/2. E. Teretia cf. T. turritelloides Bellardi, 1847), MGGC-24524/5. F. Haedropleura sp. aff. H. septangularis (Montagu, 1803), MGGC-24520/6. Views: A1, B1, C–F, lateral; A2, B2, apical. Scale bars 0.1 mm.

Fig. 8. SEM images of shell features of conoidean gastropods from early Serravallian of western Ukraine, Horodok (A, B) and Varovtsi (C–J). A, B. Pyrgocythara turrispiralata sp. nov. A. MGGC-24515/11. B. MGGC-24515/9. C, D. Raphitoma cf. R. ringicula (Boettger, 1902). C. MGGC-24522/1. D. MGGC-24522/3. E, F. Andonia sp. aff. A. transsilvanica (Hoernes and Auinger, 1890). E. MGGC-24523/1. F. MGGC-24523/3. G, H. Teretia cf. T. turritelloides (Bellardi, 1847).G. MGGC-24524/3. H. MGGC-24524/5. I, J. Haedropleura sp. aff. H. septangularis (Montagu, 1803). I. MGGC-24520/6. J. MGGC-24520/11. Views: A1, C1, E1, G1, I1, apertural; B, D, E2, H, I2, dorsal; A2, C2, F, G2, J, lateral. Scale bars 1 mm.

Fig. 2. Comparison of 10 assessed variables between allied taxa: sample mean, horizontal line; 95% confidence intervals (CI), shaded boxes; ranges, open boxes (specimen measurements in SOM 2). The mean sample is a point estimate of the population mean (μ), and the corresponding CI is a range of plausible values for μ. If two parameters have non-overlapping CI, they are considered to be significantly different. The 95% confidence interval is based on the standard error for the estimate of the mean and the t distribution. For extremely small samples (n <5; SOM 2) only ranges are reported (see Beninger et al. 2012). Abbreviations: M., Mangelia; B., Bela; P., Pyrgocythara; H., Haedropleura.