Turritella gradata Menke in Hörnes, 1855

Harzhauser, Mathias & Landau, Bernard, 2019, Turritellidae (Gastropoda) of the Miocene Paratethys Sea with considerations about turritellid genera, Zootaxa 4681 (1), pp. 1-136 : 21-24

Turritella gradata Menke in Hörnes, 1855

Figs 6C , 8E, 8F 1–2 , 9B

[ Turritella ] terebralis— Naumann, 1853: pl. 69, fig. 17.

* Turritella gradata Menke — Menke in Hörnes, 1855: 420, pl. 43, fig. 3.

Turritella gradata Menke — Menke, 1855: 557.

Turr [itella]. (Hemitr [opis].) gradata Menk. — Handmann, 1882: 212.

[ Turritella terebralis Lamarck ] var. gradata Menke in Hoernes — Dollfus, Cotter & Gomes, 1903: 4, pl. 30, figs 2–3.

Turritella terebralis Lam. var. gradata Menke — Schaffer, 1912: 160, pl. 52, fig. 18.

T. [urritella] terebralis Lam. var. gradata Menke — Guillaume, 1925: 310, pl. 10, figs 5–7.

Turritella gradata Menke in Hörnes — Stchépinsky, 1939: 31, pl. 10, figs 1–11.

Turritella gradata Menke in Hörnes — Stchépinsky, 1946: 66, pl. 33, figs 3–5.

Turritella (Turritella) terebralis Lam. var. gradata Men. — Sieber, 1949: 108.

Turritella ( Turritella ?) gradata gradata Menke — Sieber, 1960: 250, pl. 3, fig. 8/15.

Turritella gradata Menke in Hörnes, 1855 — Glibert, 1962: 102.

Turritella (T.) gradata Menke, 1854 — Steininger et al., 1973: 400, pl. 3, fig. 16.

Turritella (Turritella) gradata Menke — Stürmer, 1989: 102, pl. 2, figs 3, 5, pl. 10, fig. 1 [non fig. 4 = Zaria aquitanica Tournouër, 1874 ].

Turritella ( Turritella ?) gradata gradata Menke — Schultz, 1998: 56, pl. 21, fig. 9.

Turritella gradata Menke in Hörnes, 1856 — Harzhauser, 2002: 76, pl. 2, figs 11–13.

Turritella gradata Hörnes, 1856 — Harzhauser, 2003: 194, pl. 1, fig. 5.

Turritella gradata— Harzhauser et al., 2009b: 23, unnumbered text-fig.

non Turritella terebralis Lam. var. gradata Menke — Schaffer, 1912: 160, pl. 52, figs 17, 19 [= Turritella terebralis inaequicingulata Hölzl, 1958 ].

non [ Turritella ( Turritella ?) gradata ] forma fortissima— Sieber, 1960: 251, pl. 1, fig. 25 [= Zaria aquitanica Tournouër, 1874 ].

Type material. NHMW 1846/0037/0397 (illustrated in Hörnes, 1855, pl. 43, fig. 3), Weinsteig, Austria; early Miocene, Karpatian, designated herein as lectotype.

Studied material. 1 spec. NHMW 1846/0037/0397 (illustrated in Hörnes 1855, pl. 43, fig. 3) , 7 spec. NHMW 1846/0037/0399, 5spec. NHMW 1846/0037/0395, 5spec. NHMW2018/0168/0001, 2spec. NHMW 2000z0001/0050 (illustrated in Harzhauser 2002, pl. 2, figs 11–12), Weinsteig ( Austria) ; 1 spec. NHMW 2000z0064/0004 (illustrated in Harzhauser 2002, pl. 2, fig. 13), Gebmannsberg ( Austria) ; 1 spec. NHMW 2018/0169/0001, 4 spec. NHMW 2018/0169/0002, Stetten-Teiritzberg ( Austria) ; 1 spec. NHMW 1864/0001/0510, 5 spec. NHMW 1861/0050/0110, 3 spec. NHMW 1869/0042/0018, Niederkreuzstetten ( Austria) ; 3 spec. NHMW 1860/0050/0066, Neuruppersdorf ( Austria) ; 8 spec. NHMW 1859/0045/0015, Kleinebersdorf ; 4 spec. NHMW 1861/0050/0018, Rückersdorf ( Austria) ; 4 spec. NHMW 1861/0050/0054, Karnabrunn ( Austria) ; 4 spec. NHMW 1859/0045/0045, Grossrussbach ( Austria) ; 4 spec. NHMW 1860/0050/0110, Laa ( Austria) ; 7 spec. NHMW 1855/0045/0768, Grund ( Austria) ; 1 spec. NHMW 1863/0040/0756, Niederleis ( Austria) ; 2 spec. NHMW 1860/0047/0067, Fonte Santa ( Portugal) .

Illustrated material. Fig 8E : Weinsteig ( Austria): SL: 118.2 mm, MD: 31.7 mm, NHMW 1846/0037/0397; Figs 8F 1–2 : Stetten-Teiritzberg ( Austria): SL: 148.9 mm, MD: 41.3 mm, NHMW 2018/0169/0001; Fig. 9B : Weinsteig ( Austria): several specimens on sediment, NHMW 2018/0165/0002.

Revised description. Shell large, robust, moderately slender, of about 16 teleoconch whorls. Protoconch and earliest teleoconch whorls unknown. Early teleoconch whorls campanulate, with prominent C spiral cord and rapidly weakening B spiral cord; angulation coinciding with C spiral cord. Flat to weakly convex sutural ramp with 4 – 5 broad spiral cords with rounded tops (including weak B spiral cord); two secondary spiral cords (u, d) follow below angulation. Whorl profile of spire frustate to campanulate with periphery in abapical third of whorl; periphery strongly angulated, accentuated by prominent C spiral cord passing into rounded angulation on latest teleoconch whorls. Primary and secondary spiral cords fade out at various stages of ontogeny. Last teleoconch whorls nearly smooth except for prominent growth lines; usually markedly concave above angulation and flat to weakly convex below. Lateral sinus very steep, wide, deeply concave; LS p distinctly abapical, with faint inflection point close below adapical suture. Basal sinus weakly prosocyrt. Aperture probably subcircular (peristome lacking in all available specimens); inner lip narrowly reflected passing into thin glossy, sheet-like parietal callus. No inner lirae present.

Shell measurements and ratios. Complete specimens are rare; largest nearly complete specimen: SL = 148.9 mm, MD = 41.3 mm. Most near complete specimens range around ~ 90–100 mm. n = 8 adult specimens: AA: μ = 20.6° (σ = 1.30°), PA: μ = 16.3° (σ = 1.9°). Lateral sinus (n = 8): LS angle = 33.3° (σ = 5.7°), LS p = 1.4 (σ = 0.29), LS d = 3.5 (σ = 0.53).

Discussion. Turritella gradata is highly reminiscent of the stratigraphically older Turritella inaequicingulata ; although its largest specimens are distinctly larger than T. inaequicingulata , most specimens range within the same size class and both taxa agree also in spire angles. A separation of both species is based on the prominent C spiral cord of T. gradata and the frustate-campanulate profile of the spire whorls, and especially on the lateral sinus. This is simple concave in T. terebralis and T. inaequicingulata but develops an inflection point in the adapical half of the whorl in T. gradata .

Paleoenvironment. Turritella gradata may form “turritelline-dominated assemblages” sensu Allmon & Knight (1993) in shallow sublittoral settings. In the Austrian Korneuburg Basin, these coquinas are frequently preserved as tempestites ( Fig. 9 ) but populations in life-position were reported by Kern et al. (2011) as well. These animals dwelled in subtidal settings of a soft-bottom lagoonal environment. Stable isotope analyses by Latal et al. (2006) support this environmental interpretation because Turritella gradata values are clearly separated from the intertidal mudflat taxa.

Distribution. Central Paratethys. Karpatian (early Miocene): Korneuburg Basin: Kleinebersdorf, Stetten-Teiritzberg, Weinsteig, Rückersdorf, Grossrussbach, Karnabrunn ( Austria) ( Harzhauser 2002; herein); North Alpine Foreland Basin: Laa an der Thaya ( Austria) ( Harzhauser 2002); Pannonian Basin: Várpalota ( Hungary) ( Kókay 1971). Proto-Mediterranean Sea and northeastern Atlantic. Burdigalian: Fonte Santa ( Portugal) ( Dollfus et al. 1903; herein); Mut Basin: Burunköy (upper part) ( Turkey) (herein), Sivas Basin ( Turkey) ( Stchépinsky 1939, 1946; herein).

Turritella gradata was also mentioned from the Burdigalian of the Hadrukh Formation in eastern Saudi Arabia by Powers et al. (1966). This would be surprising in terms of paleobiogeography, because Turritella gradata seems to be restricted to the late Burdigalian of the Proto-Mediterranean and northeastern Atlantic up to Portugal and the coeval Karpatian of the Central Paratethys Sea. Reports of this species from middle Miocene Badenian localities in the North-Alpine Foreland Basin ( Sieber 1949) and the Caransebeş-Mehadia Basins ( Hinculov 1968) are based on strongly abraded and poorly preserved specimens, which are most probably reworked from older strata. Records from the Badenian of the Styrian and Klagenfurt basins ( Austria) represent misidentified Zaria aquitanica ( Tournouër, 1874) .

Figures

FIGURE 1. Paleogeography of the Paratethys during the early Miocene (Burdigalian, Eggenburgian, Sakaraulian) and the middle Miocene (Langhian, Badenian, Tarkhanian) (modified after Popov et al. 2004 and Neubauer et al. 2015).

FIGURE 2. Miocene chronostratigraphy after Gradstein et al. (2012) with regional Paratethys stages after Popov et al. (2004) and Piller et al. (2007).

FIGURE 6. Growth line traces of Turritellidae species based on own data; bold: type species of genera; black: Paratethyan species; asterisk: non-Paratethyan species (unknown basal sinuses are left blank).

FIGURE 8. A–C. Turritella inaequicingulata Hölzl, 1958, Nondorf (Austria); A1–A2. NHMW 1912/0001/0013. B1–B2. NHMW 1912/0001/0012. C1–C2. NHMW 1860/0050/0268. D1–D2. Turritella terebralis Lamarck, 1822, Léognan (France), NHMW 1850/0018/0100). E–F. Turritella gradata Menke in Hörnes, 1855. E. lectotype, Weinsteig (Austria), NHMW 1846/0037/0397. F1–2. Stetten-Teiritzberg (Austria), NHMW 2018/0169/0001.

FIGURE 9. A. Turritella inaequicingulata Hölzl 1958, NHMW 2018/0165/0001, Mörtersdorf (Austria) with a specimen of Peyrotia desmarestina (de Basterot, 1825), indicated by an arrow. B. Turritella gradata Menke in Hörnes, 1855, Weinsteig (Austria), NHMW 2018/0165/0002.