Aplus hofae, Harzhauser & Landau, 2024

Harzhauser, Mathias & Landau, Bernard M., 2024, The Colubrariidae, Eosiphonidae, Melongenidae, Pisaniidae, Prodotiidae and Tudiclidae (Gastropoda, Buccinoidea) of the Miocene Paratethys Sea, Zootaxa 5427 (1), pp. 1-110 : 32

Aplus hofae nov. sp.

Figs 13C

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Pollia d‘Orbignyi Payr. —Hoernes & Auinger 1890: 241, pl. 28, figs 9a–b [non Aplus dorbignyi ( Payraudeau, 1826) ].

Aplus sp. — Brunetti & Della Bella 2014: 7, figs 3E–F.

Type material. Holotype: NHMW 1857 /0024/0016, SL: 18.7 mm, MD: 9.1 mm, Lăpugiu de Sus ( Romania), illustrated in Hoernes & Auinger (1890: pl. 28, fig. 9).

Type locality. Lăpugiu de Sus ( Romania), Făget Basin .

Type stratum. Silt and clay of the Dej Formation.

Age. Middle Miocene, early/middle Badenian (Langhian).

Etymology. In honor of Sigrid Hof (Senckenberg Forschungsinstitut und Naturmuseum, Frankfurt/Main, Germany), who has helped us many times with pictures and information of type material.

Diagnosis. Small, moderately broad fusiform shell characterized by primary spiral cords splitting into triplets of secondary cords, swollen over axial ribs. Aperture with prominent, pointed parietal denticle, large anal denticle and eight denticles in outer lip.

Description. Small, moderately broad fusiform shell of about six teleoconch whorls; apical angle ~50°. Protoconch unknown. Early teleoconch whorls shouldered with steep subsutural ramp and incised suture. Sculpture of broad, prominent, close-set axial ribs, weakening over subsutural ramp, overrun by prominent subsutural cord and two prominent spiral cords along periphery; two weak secondary spiral cords on subsutural ramp. Shoulder becoming more rounded on penultimate and last whorl. Abapically, axial ribs weaken, and spiral cords increase in number by splitting of primary cords into triplets and intercalation of secondary cords; on last two whorls cords swollen over subobsolete ribs and secondary and tertiary cords intercalated in interspaces. Last whorl attaining 65% of total height, moderately convex at periphery and constricted at base, fasciole weak with few spiral cords. Aperture moderately narrow, ovate. Columella moderately excavated in upper half, with three blurred denticles on abapical half. Columellar callus forming thick, broad rim, sharply delimited from base. Anal canal U-shaped, distinctly incised, accentuated by prominent, pointed parietal denticle and large anal denticle. Outer lip thickened by terminal varix, with crenulated margin and eight prominent denticles close behind peristome. Siphonal canal moderately short, wide, only slightly defected to the left.

Discussion. This species was confused by Hoernes & Auinger (1890) with the extant Aplus dorbignyi ( Payraudeau, 1826) from the Mediterranean Sea. Brunetti & Della Bella (2014), who re-illustrated the Paratethyan specimen described by Hoernes & Auinger (1890), discussed differences in sculpture between the two species and stated that the shell of the Paratethyan species is more robust. Brunetti & Della Bella (2014: 7, figs 3E–F) left the Paratethyan species in open nomenclature and emphasized the necessity of a revision of the Miocene species. Apart from the ‘robustness’ highlighted by those authors (which is not obvious, as the Paratethyan specimen illustrated is not more robust that their figure of a Recent specimen of A. dorbignyi ; 2014, figs 10A–B), it is difficult to pinpoint differences between the two: the ribs are possibly stronger over the last whorl in the extant species and the siphonal canal slightly shorter. However, based on molecular data, Aissaoui et al. (2016) documented a great diversity of the genus Aplus in the Mediterranean Sea. Specimens previously identified as Aplus dorbignyi ( Payraudeau, 1826) turned out to represent three geographically separated species, comprising A. dorbignyi , A. gaillardoti ( Puton, 1856) and Aplus nodulosus (Bivona e Bernardi, 1832) . Of these only Aplus dorbignyi is known to have a fossil record, which dates back only to the Late Pleistocene ( Brunetti & Della Bella 2014). All three species are extraordinarily similar to Aplus hofae nov. sp. in their apertural features but differ in their slightly weaker spiral cords.

Therefore, despite their similarity in shell characters, it is highly unlikely that this Middle Miocene species is conspecific with any of the extant Mediterranean congeners, and we propose the name Aplus hofae nov. sp. for this Paratethyan form. Due to the overall similarity, we assume that the extant species group might be rooted in Miocene species such as Aplus hofae . For illustrations of shells of extant species (see Brunetti & Della Bella 2014: figs 10A–C; Aissaoui et al. 2016: fig. 3).

Paleoenvironment. Unknown.

Distribution in Central Paratethys. Badenian (Middle Miocene): Făget Basin: Lăpugiu de Sus ( Romania) (Hoernes & Auinger 1890).

Figures

FIGURE 1. Measurements for shell morphology; AA: apical angle, SL: shell length, MD: maximum diameter, LWH: last whorl height, AH: aperture height, AL: aperture length, AW: aperture width.

FIGURE 2. Colubraria subobscura (Hoernes & Auinger, 1884). A1–A3. NHMW 1854/0035/0170, paralectotype, Lăpugiu de Sus (Romania). B1–B2. NHMW 1859/0037/0018a, paralectotype, Lăpugiu de Sus (Romania). C1–C3. NHMW 1865/0001/0183, paralectotype, Lăpugiu de Sus (Romania). D1–D2. NHMW 1859/0037/0018b, paralectotype, Lăpugiu de Sus (Romania). E1–E3. NHMW 1874/0025/0021, lectotype, Lăpugiu de Sus (Romania). F1–F2. NHMW 2023/0338/0001, paralectotype, Lăpugiu de Sus (Romania).

FIGURE 13. A1–A2. Aplus lapugyensis (Hoernes & Auinger, 1890), NHMW 1867/0019/0082, lectotype, CoŞteiu de Sus (Romania). B. Aplus minutulus (Bałuk, 1995), holotype, Z.PAL.U.W., No. BkK–G66S, Korytnica (Poland). C1–C2. Aplus hofae nov. sp., holotype, NHMW 1857/0024/0016, Lăpugiu de Sus (Romania).