Viennella incisaeformis ( Csepreghy-Meznerics, 1956 ) Harzhauser & Landau, 2019

Harzhauser, Mathias & Landau, Bernard, 2019, Turritellidae (Gastropoda) of the Miocene Paratethys Sea with considerations about turritellid genera, Zootaxa 4681 (1), pp. 1-136 : 78-79

Viennella incisaeformis ( Csepreghy-Meznerics, 1956) new comb.

Figs 6 Af, 21A, 21B, 21C, 21D 1 –D 2

* Turritella incisaeformis n. sp. — Csepreghy-Meznerics, 1956: 384, pl. 2, fig. 36.

Turritella incisaeformis Csepreghy-Meznerics, 1956 — Strausz, 1966: 102, pl. 3, figs 18–19.

Turritella incisaeformis Cs. Meznerics — Báldi & Kókay, 1970: 278, text-fig. 5

Type material. Holotype (M.61.4303) and paratypes (M.61.4494) stored in the Hungarian Natural History Museum in Budapest ( Hungary); Badenian (middle Miocene ), Sámsonháza Formation , beside road to Ipolydamásd at Szob ( Hungary) ( Pálfy et al. 2008).

Studied material. 1 spec. M.61.4303, holotype, Ipolydamásd ( Hungary) , 2 spec. M.61.4494, paratypes, Ipolydamásd ( Hungary) ; 1 spec. NHMW 2013/0078/0716, 1 spec. NHMW 2018/0223/0004, Baden ( Austria) ; 1 spec. NHMW 2018/0303/0001, 8 spec. NHMW 2018/0303/0002, 3 spec. NHMW 1997z0178/1013, Bad Vöslau ( Austria) .

Illustrated material. Fig. 21A : SL: 24.0 mm, MD: 6.5 mm, M.61.4303, holotype, Ipolydamásd ( Hungary); Fig. 21B : SL: 19.6 mm, MD: 5.6 mm, NHMW 2013/0078/0716, Baden ( Austria); Fig. 21C : SL: 17.9 mm, MD: 5.3 mm, NHMW 2018/0223/0004, Baden ( Austria); Figs 21D 1 –D 2 : SL: 16.5 mm, MD: 5.3 mm, NHMW 2018/0303/0001, Bad Vöslau ( Austria).

Revised description. Shell small, moderately slender, comprising at least 15 teleoconch whorls. Protoconch comprising about 2.5 low, convex whorls of ~250 μm diameter. First teleoconch whorl angulated at mid-whorl, co- inciding with B spiral cord. Primary spiral cords starting with B cord followed by C cord on first teleoconch whorl, followed by delicate A spiral cord on second teleoconch whorl; r, t and u secondary cords intercalated on third whorl, soon rivaling primary cords in strength. Number of spiral cords increasing to seven by intercalation of s spiral cord on fifth teleoconch whorl. Post-neanic whorls bearing seven prominent, raised spiral cords with convex tops. Spiral cord at adapical suture most prominent separated from following cord by broader interspace, resulting in faint concavity in which a delicate tertiary spiral cord may be intercalated. Whorl profile changing from weakly convex to flat sided on neanic whorls and to weakly convex on late teleoconch whorls, with maximum diameter below midwhorl. Suture deeply incised, slightly canaliculate on neanic whorls and early teleoconch. Lateral sinus angle low to moderately steep; wide, with faint inflection points, moderately deep. Basal sinus unknown; aperture missing in all specimens. Up to 10 prominent, discontinuous palatal and basal spiral lirae on inner side of teleoconch whorls.

Shell measurements and ratios. No complete specimens available; based on largest fragment, maximum SL = ~ 23 mm, MD = ~ 5.8 mm. AA: 20–23°, PA: 13–15°. Lateral sinus (n = 5): LS angle = 11.1° (σ = 1.9°), LS p = 0.9 (σ = 0.1), LS d = 5.9 (σ = 0.8).

Discussion. Viennella incisaeformis ( Csepreghy-Meznerics, 1956) is a unique species among the Miocene turritellids, characterized by its small size, nearly flat sided profile and prominent, uniform spiral cords. Until now, however, the species was poorly understood due to the very small illustration and short description of this rare species by Csepreghy-Meznerics (1956). Especially its separation from Turritellinella subuliformis ( Boettger, 1907) and Viennella ignorata new sp. was impossible based only on the original data and all three taxa have been mixed in museum lots. To clarify the status of this species, we re-illustrate the holotype of Viennella incisaeformis ( Fig. 21A ). Turritellinella subuliformis differs obviously in its convex whorls, deeper lateral sinus, and the presence of secondary and tertiary spiral sculpture. The presence of secondary spiral sculpture and the somewhat imbricate whorl profile distinguish Viennella ignorata new sp. from Viennella incisaeformis (see discussion below). “ Turritella ” laevissima Mayer, 1866 , from the Burdigalian of the Torino Hills in Italy, is superficially similar but differs from V. incisaeformis in its much weaker spiral sculpture. Caprotti (1975) discussed a relationship of V. incisaeformis with the Miocene to Pliocene Mediterranean “ Turritella ” aspersa Mayer, 1866. This, however, is rather unlikely in respect to the convex whorls of “ T. ” aspersa and different type of spiral sculpture (9 rugose spiral cords equal in width to their interspaces covered by fine spiral threads) ( Landau et al. 2004).

Paleoenvironment. The species is found in basinal clays suggesting middle to outer neritic environments. Distribution. Central Paratethys. Badenian: Vienna Basin: Baden, Bad Vöslau (herein); Pannonian Basin:

Ipolydamásd at Szob ( Hungary) ( Csepreghy-Meznerics 1956).

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 21. A–D. Viennella incisaeformis (Csepreghy-Meznerics, 1956). A. Holotype, Ipolydamásd (Hungary), M.61.4303. B. Baden (Austria), NHMW 2013/0078/0716. C. Baden (Austria), NHMW 2018/0223/0004. D1–D2. Bad Vöslau (Austria), NHMW 2018/0303/0001. E–I. Viennella ignorata new sp. E. Paratype, Bad Vöslau (Austria), NHMW 2018/0303/0003. F. Holotype, Steinebrunn (Austria), NHMW 1963/0528/0000. G. Paratype, Gainfarn (Austria), NHMW 2018/0272/0005. H. Para- type, Steinebrunn (Austria), NHMW 1963/0551/0000. I. Paratype, Steinebrunn (Austria), NHMW 1871/0010/0379.