Amaea grunerti, Harzhauser & Landau, 2025

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 : 30-33

publication ID	https://doi.org/10.11646/zootaxa.5630.1.1
publication LSID	lsid:zoobank.org:pub:89462472-D932-4255-880F-C6EF15220A31
persistent identifier	https://treatment.plazi.org/id/03D787A4-FFF8-FFC5-FF3F-F993FA329689
treatment provided by	Plazi
scientific name	Amaea grunerti
status	sp. nov.

Treatment

Amaea grunerti sp. nov.

Figs 2L View FIGURE 2 , 11C–F View FIGURE 11

Scalaria amoena Phil.— Hoernes 1875: 362 , pl. 10, figs 8–9 [non Amaea amoena ( Philippi, 1844) ].

Amaea (Acrilla) amoena hoernesi Pant.— Steininger 1973: 407 , pl. 4, fig. 9 [non Scalaria (Cirsotrema) hornesi Pantanelli, 1886 ].

Scalina subreticulata (d’Orbigny, 1852) View in CoL — Harzhauser et al. 2014: 93, pl. 3, figs 2, 3, 4a–b [non Amaea subreticulata (d’Orbigny, 1852) View in CoL ].

Scalina subreticulata (d’Orbigny, 1852) View in CoL — Kovács et al. 2023: 44, fig. 60 [non Amaea subreticulata (d’Orbigny, 1852) View in CoL ].

Type material. Holotype, GBA 1875/01/37, SL: 53.4 mm, MD: 16.3 mm, Ottnang ( Austria), illustrated in Hoernes (1875: 362, pl. 10, fig. 9), Figs 2L View FIGURE 2 , 11D View FIGURE 11 1 –D View FIGURE 1 2 View FIGURE 2 . Paratypes, NHMW 2014 View Materials /0379/00334, SL: 34 mm , MD: 12.5 mm, Allerding ( Austria), illustrated in Harzhauser et al. (2014: pl. 3, fig. 3), Fig 11C View FIGURE 11 . GBA 1875/01/37, SL: 33.6 mm , MD: 14.9 mm, Ottnang ( Austria), illustrated in Hoernes (1875: 362, pl. 10, fig. 8), Figs 11E View FIGURE 11 1 –E View FIGURE 1 2 View FIGURE 2 . NHMW 2014 View Materials /0379/00333, SL: 18.8 mm , MD: 8.5 mm, Allerding ( Austria), illustrated in Harzhauser et al. (2014: pl. 3, fig. 2), Fig 11F View FIGURE 11 .

Type locality. Ottnang ( Austria), North Alpine Foreland Basin .

Type stratum. Ottnang Formation.

Age. Early Miocene, early Ottnangian (mid-Burdigalian).

Etymology. In honor of Patrick Grunert (University Köln, Germany) in recognition of his contributions on the stratigraphy of the North-Alpine Foreland Basin.

Diagnosis. Very large, moderately slender shell with convex whorls, faint shoulder angulation and prominent cancellate to axially elongate rectangular sculpture of thin, low lamellae crossing up to six slightly broader primary cords plus one primary cord on subsutural ramp.

Description. Shell very large, moderately slender (apical angle ~22°). Protoconch unknown. Teleoconch of more than ten relatively low whorls. Whorls strongly convex with steep, straight sided to weakly convex subsutural ramp, faint shoulder angulation and convex periphery placed just above mid-whorl. Suture deeply impressed, linear. Sculpture of delicate, weakly raised, prosocline lamellae, not aligned axially (~16: ~45: ~55). Broader, band-like, flat varices may develop by amalgamation of several lamellae. Spiral sculpture on early whorls of one spiral cord on subsutural ramp and four to five primary spiral cords below. Sixth spiral cord intercalated at or above abapical suture on later whorls. Spiral sculpture equal in strength and elevation to lamellae, forming sharp, regularly cancellate to weakly axially elongate rectangular sculpture. Secondary spiral cords may be intercalated in some specimens. Last whorl attaining about 35% of total height, basal angulation rounded to indistinctly angled delimited by narrow peribasal cord of same strength as primary spirals, base weakly convex with thin lamellae and numerous prominent spiral cords. Fasciole very short, broad with prominent growth lines. Aperture ovate. Columella weakly concave. Outer lip thin. Basal lip slightly excavated. Columellar callus with moderate swelling, forming broad, relatively thick rim, attached to base. No umbilicus.

Discussion. Already Pantanelli (1886) recognized that the Miocene shells described by Hoernes (1875) were not conspecific with Amaea amoena ( Philippi, 1844) and discussed the specimens illustrated by Hoernes (1875) from Ottnang in his description of Scalaria (Cirsotrema) hörnesi from the Langhian of Pantano of Reggio Emilia in Italy. He tentatively suggested that both records were conspecific but emphasized, that this conclusion was based solely on the illustration in Hoernes (1875) and not direct comparison. In our opinion the two records are not conspecific and therefore, the name Amaea hoernesi ( Pantanelli, 1886) refers to the species occurring in the Middle Miocene (Langhian) of Italy and cannot be used for the Ottnangian species, as done by Sieber (1956) and Steininger (1973). Sacco (1891: 53) proposed Scalaria (Cirsotrema) mioeuropaeum as name for Scalaria (Cirsotrema) hoernesi Pantanelli, 1886 because he considered it to be a homonym of Scalaria pumicea hornesi De Gregorio, 1889 . Both names, however, are available because Article 57.6 of the ICZN (1999) states: “ a one-letter difference between species-group names combined with the same generic name is sufficient to prevent homonymy ”. According to article 32.5 of the ICZN special characters like ä, ö and ü used in species names before 1985 must be corrected to ae, oe and ue. Therefore, Scalaria hornesi De Gregorio, 1889 and S calaria (Cirsotrema) hoernesi Pantanelli, 1886 ) are both available.

Amaea grunerti sp. nov. differs from the Middle Miocene A. hoernesi in its larger size, its less angled basal angulation and its convex base. Amaea hoernesi has three primary spiral cords with secondary cords intercalated, whereas Amaea grunerti has five to six primary spiral cords and usually lacks prominent secondary cords. In addition, A. hoernesi has evenly convex whorls and lamellae, which are raised above the spiral cords, whereas A. grunerti has a faint shoulder angulation and spiral and axial sculpture are almost equal in strength. A specimen from the Ottnangian of Hungary, illustrated by Kovács et al. (2023) as Scalina subreticulata (d’Orbigny, 1852) differs slightly from the Austrian specimens in its broader, convex primary spiral cords and the presence of prominent secondary spiral cords but otherwise agrees in the pattern of primary cords. Therefore, we treat both occurrences tentatively as conspecific.

Amaea grunerti sp. nov. was misidentified as Scalina subreticulata (d’Orbigny, 1852) View in CoL by Harzhauser et al. (2014) and Kovács et al. (2023), which was originally described by Michelotti (1847: 161, pl. 6, fig. 13) as Scalaria reticulata , from “ L colline de Turin et Tortone ” The name was preoccupied (e.g., Sowerby 1829; Philippi 1844) and therefore, d’Orbigny (1852; 31) introduced Scalaria subreticulata View in CoL as new name for the Italian species. Later, Sacco (1891: 62, pl. 2, fig. 51) revised and illustrated that species, which differs from A. grunerti quite distinctly in its deeply incised suture, marked basal angulation with prominent peribasal spiral cord and the close-set sculpture of prominent primary and secondary spiral cords, which predominate over the much weaker axial lamellae. Scalaria (Acrilla) amoena scabberimoides Sacco, 1891 and Scalaria (Acrilla) amoena taurocancellata Sacco, 1891 , both from the Burdigalian or Langhian of the Colli Torinesi , are probably subjective junior synonyms of Amaea subreticulata (d’Orbigny, 1852) View in CoL (see Sacco 1891: pl. 2, figs 52–53).

Amaea grunerti was confused by Hoernes (1875) with Amaea amoena , from the Oligocene of the North Sea, which differs in its less incised suture and less convex whorls. It has broad spiral cords that are separated by narrow interspaces ( Janssen 1978: pl. 13, fig. 65).

Acrilla phoenix De Boury, 1913 , from the Early Miocene of France (de Boury 1913 a), differs in its more prominent basal angulation, wider spaced lamellae and distinct secondary spiral cords (see Cossmann & Peyrot 1922: 157, pl. 4, figs 91–92; https://science.mnhn.fr/institution/mnhn/collection/f/item/j05876?listIndex=83&listC ount=106). Amaea subreticulata View in CoL of Glibert (1952: pl. 7, fig. 1), from the Early Miocene of the North Sea, has only three primary spiral cords along the periphery and a weaker shoulder angulation, and represents a further Amaea sp.

Paleoenvironment. Tide- and storm-influenced outer–middle neritic depositional settings ( Grunert et al. 2012).

Distribution in Central Paratethys. Ottnangian (Early Miocene): North Alpine Foreland Basin: Allerding, Ottnang ( Austria) ( Hoernes 1875; Harzhauser et al. 2014); Early Miocene North Hungarian Basin: Parádfürdö ( Hungary) ( Kovács et al. 2023).

Genus Anguloacrilla nov. gen.

Type species. Scalaria (Acrilla) kimakowiczi Boettger, 1896 . Middle Miocene , Central Paratethys Sea ( Romania) .

Etymology. Coinage of angulus (Latin for angle) and Acrilla , referring to the angled shoulder.

Diagnosis. Medium-sized, moderately slender, finely coronate shells with deeply impressed suture, relatively low, convex whorls with narrow, shallow subsutural ramp, numerous close-set lamellae, often forming low spines at shoulder, with numerous spiral threads in interspaces, spirals override the lamellae giving them irregular or granular appearance, marked basal angulation with flat basal disc and prominent peribasal cord; abapical part of the outer lip ends in short spout.

Description. Medium-sized, moderately slender, finely coronate shells. Protoconch unknown from type species. Teleoconch whorls relatively low, moderately convex with narrow, shallow subsutural ramp, more or less prominent shoulder angulation, typically reinforced by weakly protruding spines. Periphery placed mid-whorl. Suture deeply impressed. Sculpture of numerous weakly prosocline lamellae and more or less prominent spiral threads in interspaces. Spirals override axials causing delicate granulation on laminar crests. Last whorl attaining about 35% of total height with very prominent basal angulation, coinciding with prominent peribasal cord. Basal disc flattened with weak laminae and spiral threads. Aperture semicircular, thin. Peristome unknown. Abapical part of the outer lip ends in short spout. Columellar callus forming broad rim, adherent but well delimited from base. No umbilicus.

Discussion. Since Boettger (1896), the species placed herein in Anguloacrilla nov. gen. were treated as Acrilla or Amaea (Acrilla) (e.g., Kojumdgieva in Kojumdgieva & Strachimirov 1960; Landau et al. 2013). The type species of Acrilla is the Recent Scalaria acuminata G.B. Sowerby II, 1844 from the Indo-West Pacific, which is a tall shell with numerous, evenly convex whorls lacking any shoulder angulation and with close-set, narrow, convex, sigmoidal axial ribs instead of lamellae (see Adams 1860: pl. 35, fig. 130; https://www.gbif.org/occurrence/gallery?taxon_ key=6126747). According to MolluscaBase eds (2024c), Acrilla acuminata is the only living species of this genus. Acrilla differs distinctly from Anguloacrilla , which has comparatively low whorls with narrow subsutural ramp, thin lamellae and distinct spiral sculpture.

Some Amaea species (type species Scalaria magnifica G. B. Sowerby II, 1844 ) may also develop rather low, convex whorls, but Amaea lacks shoulder angulation. Among the extant Amaea species, Amaea sericogazea (Masahito, Kuroda & Habe in Kuroda, Habe & Oyama, 1971) is most reminiscent of Anguloacrilla but lacks shoulder angulation and has no protruding lamellae close to the adapical suture (see Garcia 2003: fig. 18).

The extant ‘Gyroscala’ mikeleei García, 2003, from Indonesia, is reminiscent of Anguloacrilla in its slightly coronate shoulder and thin lamellae but lacks a basal angulation and does not develop a peribasal cord (see García 2003: figs 51–52) [this species was placed in Gyroscala de Boury, 1887 by García (2003) but differs strongly from the type species Gyroscala commutata ( Monterosato, 1877) , which is characterized by few, very prominent varices aligned axially].

Adiscoacrilla Sacco, 1890 [type species Acrilla coppii de Boury, 1890 , Pliocene, Italy] has a comparable sculpture of prominent, thin lamellae and distinct spiral cords but lacks a shoulder angulation and is not coronate.

Included species. Scalaria (Acrilla) kimakowiczi Boettger , Anguloacrilla schwarzhansi sp. nov., Anguloacrilla lima sp. nov., 1896 (all Middle Miocene, Central Paratethys Sea); Anguloacrilla karamanensis sp. nov. (Middle Miocene, Proto-Mediterranean Sea); an unnamed species described by Janssen (1967: pl. 14, fig. 4) (Middle Miocene, North Sea). The genus might be rooted in an Eocene group, such as Scalaria reticulata Solander in Brander, 1766 ( Great Britain), Scalaria semicostata J. Sowerby, 1814 View in CoL ( France) and Scalaria grignonensis Cossmann, 1888 ) ( France), which agree largely with Miocene Anguloacrilla species but have only a faint shoulder angulation (e.g., Savazzi & Sasaki 2004: fig. 11D; https://science.mnhn.fr/institution/mnhn/collection/f/item/j02108?listIndex=78& listCount=106; https://science.mnhn.fr/institution/mnhn/collection/f/item/j02109?listIndex=105&listCount=106).