Adiscoacrilla? orientalis ( Friedberg, 1928 )

Harzhauser, Mathias & Landau, Bernard M., 2025, The Epitoniidae (Gastropoda, Epitonioidea) of the Miocene Central Paratethys Sea-an overwhelming diversity, Zootaxa 5630 (1), pp. 1-142 : 28-29

Adiscoacrilla? orientalis ( Friedberg, 1928)

Fig. 10A

* Scala orientalis Friedb.— Friedberg 1928: 606 , pl. 38, figs 24 [not fig. 23 = unidentifiable Epitoniidae ].

Scala orientalis Friedb.— Friedberg 1938: 84 .

Scala orientalis Friedberg, 1938 — Zelinskaya et al. 1968: 173.

non Scala cf. orientalis Friedberg— Atanacković 1969: 200 , pl. 9, figs 13–13a [= Nodiscala macilenta (De Boury in Cossmann, 1912)].

non Acrilla (Acrilla) orientalis (Friedberg) —Bałuk: 1975, 176, pl. 21, figs 1–2 [= Adiscoacrilla walaszczyki sp. nov.].

non Scala cfr. orientalis Friedberg, 1928 — Švagrovský 1982: 28: pl. 9, fig. 7 [= unidentifiable Epitoniidae ].

Type material. Lectotype (designated herein), specimen illustrated in Friedberg (1928: pl. 38, fig. 24), SL: 6 mm [fide Friedberg 1928: 606; this differs from the scale on plate 38, which suggests a size of about 3 mm], Szuszkowce ( Ukraine), Fig. 10A (re-illustrated from Friedberg 1928). We are not aware of the whereabouts of the material. Friedberg (1928) illustrated two specimens, which are almost certainly not conspecific. The fragmentary specimen illustrated on pl. 38, fig. 23 differs from the lectotype in its slenderer shape, prosocline lamellae and represents another Epitoniidae species.

Revised description. Small, moderately broad conical (apical angle 27°). Protoconch and early teleoconch whorls unknown. Teleoconch whorls evenly convex with periphery placed mid-whorl. Suture moderately impressed. Sculpture of prominent, moderately raised, slightly prosocline lamellae, not aligned axially, separated by wider interspaces (?: ~16: ~16). At least one varix per whorl. Interspaces with delicate spiral threads. Last whorl attaining about 40% of total height with weakly angled base delimited by weak peribasal cord. Lamellae weakening over base. Fasciole short, broad, with prominent growth lines. Aperture subcircular, columella nearly straight. Columellar callus forming narrow rim. Parietal callus weak, peristome thickened, duplex, inner layer continuous, narrow. No umbilicus.

Discussion. This species is only known from a single, fragmentary specimen. Its placement in Adiscoacrilla is tentative. The weakly angled base excludes placement in the otherwise comparable Sodaliscala de Boury, 1909 [type species Sodaliscala multistriata ( Say, 1826) ; present-day, western Atlantic]. The shell seems to be composed of an outer and inner layer; the inner one whitish. The two layers are most obvious at the labial varix, where they form a ‘double rim’. We are not sure what the implication of this is, but it is also seen in other epitoniids, but not in other members of the genus Adiscoacrilla .

Paleoenvironment. Probably shallow marine.

Distribution in Central Paratethys. Badenian (Middle Miocene): Polish-Ukrainian Fore-Carpathian Basin: Shushkivtsi (= Szuszkowce) ( Ukraine) ( Friedberg 1938).

Genus Amaea H. Adams & A. Adams, 1853

Type species. Scalaria magnifica G.B. Sowerby II, 1844 ; subsequent designation by de Boury (1909a: 258). Present-day, Japan.

Diagnosis. “ Thin shell, quite large, turriculate, with convex and cancellated whorls; the base of the last whorl is convex and bears a rudimentary disc; but the main characteristic of this acrilliform genus is its oval opening, holostome in front, narrowed behind, and particularly the columellar bulge that is not seen in any other Scalidae ; the peristome is weak, except when it coincides with one of the varices. ” (translated from Cossmann 1912: 25).

Discussion. Some of the discussed species have been placed previously in Scalina Conrad, 1865 by us ( Harzhauser et al. 2014). However, Scalina Conrad, 1865 (type species Scala staminea Conrad, 1860 , Eocene, Alabama, USA) is currently treated as subjective junior synonym of Amaea by MolluscaBase eds. (2014d), which is followed herein. DeVries (2007: 231) distinguished Scalina from Amaea based on “ their contrasting basal and lateral sculpture ”. DeVries (2007) described several Scalina species from the Early Miocene to Pliocene of the western Atlantic and eastern Pacific that are morphologically clearly closely related to the Proto-Mediterranean- Paratethyan species discussed herein. Nevertheless, several extant Amaea species, such as Amaea gazeoides Kuroda & Habe in Habe 1961 and Amaea splendida (de Boury, 1913 a) display nearly identical sculpture and support the synonymization of both genera.

Figures

FIGURE 10.A. Adiscoacrilla? orientalis (Friedberg, 1928), lectotype, Szuszkowce (Ukraine). B1–B2. Adiscoacrilla laticostata (Bałuk, 1975), holotype, Z.PAL.U.W., BkK-G 35, Korytnica (Poland).