Megaclavatula nemethi ( Kovács & Vicián, 2021 ) Harzhauser & Landau & Janssen, 2022

Harzhauser, Mathias, Landau, Bernard & Janssen, Ronald, 2022, The Clavatulidae (Gastropoda, Conoidea) of the Miocene Paratethys Sea with considerations on fossil and extant Clavatulidae genera, Zootaxa 5123 (1), pp. 1-172 : 70-71

Megaclavatula nemethi ( Kovács & Vicián, 2021) nov. comb.

Figs 22C 1 –C 2 , D, 5 , 6

Clavatula taurinensis Mayer (in Bellardi)— Strausz 1966: 403, pl. 14, figs 20–23 [non Neoperrona taurinensis ( Bellardi, 1877) ].

* Perrona nemethi n. sp. — Kovács & Vicián 2021: 147, pl. 3, figs 30–32, pl. 4, figs 1–3.

Type material. Holotype: HNHM, PAL 2021.21 .1, SL: 36.0 mm, MD: 12.4 mm, Letkés ( Hungary), illustrated in Kovács & Vicián (2021, pl. 3, figs 30–31), figs 22C 1 –C 2 . Paratypes: NHMW, 2021/0002/0003, SL: 25.0 mm , MD: 10.0 mm, Letkés ( Hungary), illustrated in Kovács & Vicián (2021, pl. 4, figs 1–2), figs 22D, 4 Ac ; NHMW, 2021/0002/0004, SL: 41.0 mm, MD: 15.4 mm, Letkés ( Hungary), illustrated in Kovács & Vicián (2021, pl. 4, fig. 3) .

Revised description. Shell medium-sized, moderately broad fusiform with conical spire, apical angle ~35°. Protoconch not preserved. Teleoconch of at least ten whorls. Early teleoconch whorls straight-sided with tripartite sculpture, subsutural and mid-cord finely beaded, suprasutural cord with larger beads made bifid by intercalation of a spiral groove. On sixth whorl subsutural cord becomes very weak collar, smooth to subobsoletely beaded; midrow of beads fades leaving smooth, very weakly concave mid-portion. Suprasutural beads become opisthocline, axially elongated, subdivided by further narrow spiral cords. Entire surface covered by even finer subobsolete threads. Suture narrowly impressed, linear. Last whorl 65% of total height. Subsutural cord weak, subsutural ramp of mid-width, weakly concave. Shoulder broad, delimited by row of weak tubercles, somewhat inflated at midwhorl. Base weakly delimited, strongly constricted. Siphonal fasciole poorly developed. Sculpture of spiral threads on entire whorl and weak, subobsolete cords below shoulder. Aperture moderately wide, pyriform. Outer lip not thickened, smooth within. Anal sinus moderately wide, moderately deep, asymmetrically U-shaped, with apex at mid-ramp. Siphonal canal moderately long, moderately wide, straight, shallowly notched at tip. Columella strongly excavated in upper third, weakly twisted at fasciole, smooth. Columellar and parietal callus thin, adherent, forming indistinct callus rim.

Discussion. Within Megaclavatula this species has the most reduced sculpture. Its tripartite sculpture of early teleoconch whorls excludes a placement in Perrona as suggested by Kovács & Vicián (2021). Megaclavatula nemethi resembles Tomellana dulaii nov. sp. in general shape but has a slightly higher spire and a deeper and narrower anal sinus. Moreover, T. dulaii lacks the beads at the abapical suture and lacks a tripartite sculpture of early teleoconch whorls. Tomellana semimarginata ( Lamarck, 1822) is also slightly reminiscent of M. nemethi , but lacks a beaded spiral cord at the abapical suture, is much larger, has a much higher spire and axial riblets on the early teleoconch whorls. For further discussions see Kovács & Vicián (2021).

Megaclavatula nemethi was already recorded from Letkés by Strausz (1966), who confused the specimens with Neoperrona taurinensis ( Bellardi, 1877) , described from the Langhian of Italy. Neoperrona taurinensis is slightly reminiscent of M. nemethi in its beads along the abapical suture of early teleoconch whorls, but is much more slender and has a much higher spire (see Bellardi 1877: 187, pl. 6, fig. 10). The species compared above illustrate the importance of the early teleoconch whorl sculpture in generic placement. All the above species have similar late teleoconch whorl features, but differ markedly in their neanic whorls.

Paleoenvironment. The occurrence at Letkés ( Hungary) suggests a preference for inner neritic environments in the vicinity of corals ( Kovács & Vicián 2013).

Distribution in Central Paratethys. Badenian (middle Miocene): Pannonian Basin: Letkés ( Hungary) ( Kovács & Vicián 2021).

Figures

FIGURE 1. A. Map of central and south–eastern Europe, representing the area that was partly covered by the Central Paratethys Sea. The white insert corresponds to the area that is restored in the palaeogeographic map below. B. Paleogeography of the Middle Miocene Paratethys Sea showing the most important sedimentary basins (NAFB: North Alpine Foreland Basin, E.-Sopr B: Eisenstadt–Sopron Basin).

FIGURE 2. Descriptive terms used in descriptions and measurements to shell morphology, whorl profiles and anal sinus. SL: shell length, MD: maximum diameter, AA: apical angle, LWH: last whorl height, AH: aperture height.AL: aperture length.AW: aperture width.

FIGURE 5. Anal sinus morphology of Paratethyan Clavatulidae.

FIGURE 6. Apertures of Paratethyan Clavatulidae (C. = Clavatula, ‘C.’ = ‘Clavatula’, G. = Granulatocincta, M. = Megaclavaltula, O. = Olegia).

FIGURE 22 A1–A3. Megaclavatula laevigata (Eichwald, 1830), NHMW 1846/0037/0308, Baden (Austria). B1–B3. Megaclavatula subsculpta (Schaffer, 1912), lectotype, KM Inv. No. F/1125, Maria Dreieichen (Austria). C1–C2. Megaclavatula nemethi (Kovács & Vicián, 2021), holotype, HNHM, PAL 2021.21.1, Letkés (Hungary). D. Megaclavatula nemethi (Kovács & Vicián, 2021), paratype, NHMW 2021/0002/0003, Letkés (Hungary). E1–E2. Megaclavatula? szontaghyi (Strausz, 1926), holotype, M.116, Bán, Baranya County (Hungary). F. Megaclavatula neudorfensis (Schaffer, 1898), holotype, NHMW 2021/0137/0001, Devínska Nová Ves (Slovakia). G1–G3. Megaclavatula pilleri nov. sp., holotype, NHMW 1949/0005/0051a, Baden-Sooss (Austria). H1–H3. Megaclavatula pilleri nov. sp., paratype, NHMW 1949/0005/0051b, Baden-Sooss (Austria).