Monostiolum hungaricum ( Csepreghy-Meznerics, 1954 )

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 : 49-51

publication ID	https://doi.org/ 10.11646/zootaxa.5427.1.1
publication LSID	lsid:zoobank.org:pub:923206B0-E8C5-4FD5-B882-55009ABB0282
persistent identifier	https://treatment.plazi.org/id/03CE9F1C-FFAA-0C75-FF65-F94FE8EEFD4A
treatment provided by	Plazi
scientific name	Monostiolum hungaricum ( Csepreghy-Meznerics, 1954 )
status

Treatment

Monostiolum hungaricum ( Csepreghy-Meznerics, 1954)

Figs 15H View FIGURE 15 , 25A–D View FIGURE 25

Triton varians Michti. View in CoL —Hörnes 1856: 670, pl. 51, figs 3a–b [non Monostiolum varians ( Michelotti, 1847) ].

Pollia varians Michti. —Hoernes & Auinger 1890: 240 [non Monostiolum varians ( Michelotti, 1847) ].

* Philbertia hungarica n. sp. — Csepreghy-Meznerics 1954: 54, 142, pl. 7, figs 16–17, 21–22.

C [antharus]. (P [ollia]). varians (Micht.) — Sieber 1958: 151 [non Monostiolum varians ( Michelotti, 1847) ].

“ Philbertia ”(?) hungarica Csepreghy-Meznerics — Strausz, 1966a: 444, pl. 79, fig. 4.

Philbertia hungarica Csepreghy-Meznerics —Pálfy et al. 2009: 108.

Aplus varians ( Michelotti, 1847) View in CoL — Vicián et al. 2017: 270, pl. 3, figs 1–3 [non Monostiolum varians ( Michelotti, 1847) ].

Aplus varians ( Michelotti, 1847) View in CoL — Kovács & Vicián 2023: 252, figs 12H–I [non Monostiolum varians ( Michelotti, 1847) ]. Type material. Holotype: M. 52/1441, Hungarian Natural History Museum, Budapest, SL: 10.9 mm, MD: 4.3 mm, Sámsonháza ( Hungary), Badenian (Middle Miocene), illustrated in Csepreghy-Meznerics 1954 (pl. 7, figs 16–17, 21–22).

Illustrated material. NHMW 2023/0348/0003, SL: 15.1 mm, MD: 5.7 mm, Steinebrunn ( Austria), Figs 25A View FIGURE 25 1 – A View FIGURE 1 2 View FIGURE 2 . NHMW 1869/0001/0348, SL: 14.3 mm, MD: 5.5 mm, Steinebrunn ( Austria); illustrated in Hörnes (1856: pl. 51, fig. 3), Figs 25B View FIGURE 25 1 –B View FIGURE 1 2 View FIGURE 2 . NHMW 1865/0001/0561, SL: 14.9 mm, MD: 5.7 mm, Steinebrunn ( Austria), Fig. 25C View FIGURE 25 . NHMW 1868/0001/0094, SL: 16.5 mm, MD: 5.9 mm, Steinebrunn ( Austria), Figs 15H View FIGURE 15 , 25D View FIGURE 25 .

Additional material. 53 spec., NHMW 1871 View Materials /0010/0338, Steinebrunn ( Austria) ; 1 spec., NHMW 2023 View Materials /0348/0004, Steinebrunn ( Austria) ; 2 spec., NHMW 1863 View Materials /0015/0658, Niederleis ( Austria) ; 2 spec., NHMW 1862 View Materials /0033/0023, Pöls ( Austria) ; 21 spec., NHMW 1870 View Materials /0033/0075, Lăpugiu de Sus ( Romania) ; 8 spec., NHMW 1855 View Materials /0043/0012, Lăpugiu de Sus ( Romania) .

Revised description. Medium-sized, slender shell of up to six teleoconch whorls with weakly cyrtoconoid spire; apical angle ~50°. Protoconch moderately high conical of three weakly convex whorls; diameter: 680 μm, height: 620 μm. Second protoconch whorl weakly carinate below mid-whorl. Early teleoconch whorls weakly convex, periphery close above deeply incised suture. Sculpture of broad, prominent axial ribs, separated by slightly narrower interspaces, overrun by three broad spiral cords weakly swollen over ribs. On second teleoconch whorl adapical spiral cord splits into two primary cords. Later whorls strongly increasing in height, becoming increasingly convex. Single secondary cord becomes intercalated in each spiral interspace, rapidly increasing in strength and becoming equal to primaries in some specimens ( Figs 25A, B, D View FIGURE 25 ), or remaining slightly weaker in others ( Fig. 25C View FIGURE 25 ). Last whorl attaining ~40% of total height, moderately convex, with moderately constricted base, bearing about 18–20 subequal spiral cords, swollen to weakly nodulose over ribs, with occasional tertiary thread intercalated in some interspaces; fasciole broad, indistinct with prominent spiral cords. Aperture narrow, ovate, Columella weakly excavated, distinctly angled at transition to siphonal canal, accentuated by prominent denticle, smooth above. Columellar callus forming broad, prominent rim, sharply delimited from base. Anal canal moderately incised Ushaped, adjoined by low parietal denticle. Outer lip thickened by terminal varix, with about 10–12 prominent, elongate denticles slightly behind peristome, lowermost denticle at transition to siphonal canal slightly stronger, oriented in axial direction. Siphonal canal moderately short, wide, shallowly notched, slightly deflected to the left.

Discussion. Kovács & Vicián (2023) studied the holotype of Philbertia hungarica Csepreghy-Meznerics, 1954 and recognized that it was conspecific with the species described by Hörnes (1856) and (Hoernes &Auinger 1890) as Triton varians and Pollia varians respectively. Monostiolum hungaricum was identified as Triton varians Michelotti, 1847 by Hörnes (1856) and subsequent authors. The Italian species was illustrated in Michelotti (1847: 250, pl. 16, fig. 10). In addition, we consider Pollia angusta Bellardi, 1873 to be conspecific with Monostiolum varians (see Bellardi 1873: 181, pl. 12, fig. 20). Based on these two illustrations, Monostiolum hungaricum differs from M. varians in its higher spire, more convex whorls and more deeply incised suture. In his Latin description, Bellardi (1873: 181) emphasized the prominent axial ribs and weak spiral sculpture of M. varians , whereas the Paratethyan species has weak axial ribs and prominent spiral sculpture. Nevertheless, better illustrations and descriptions of M. varians will be needed to clarify its relation to M. hungaricum . The specimen illustrated by Kovács & Vicián (2023) has an extra varix at 180 degrees from the terminal varix and is not fully grown. Its terminal varix is not fully formed and labial denticles are absent.

The specimen illustrated by Bellardi (1873: 180, pl. 12, fig. 19) as Pollia varians has a short spire and an inflated last whorl and is placed herein in Dianthiphos . Tritonidea productocostata Sacco, 1904 , established as subspecies of Tritonidea varians by Sacco (1904: 59, pl. 14, figs 69–70) differs from M. varians and M. hungaricum in its fewer and wider spaced spiral cords. This species is also placed in Dianthiphos by us.

Paleoenvironment. Shallow marine, inner neritic.

Distribution in Central Paratethys. Badenian (Middle Miocene): Vienna Basin: Steinebrunn, Niederleis ( Austria) (Hoernes & Auinger 1890); Styrian Basin: Pöls ( Austria) (Hoernes & Auinger 1890); Pannonian Basin: Bánd, Letkés, Márkháza ( Hungary) ( Vicián et al. 2017); Bükk Mountains: Borsodbóta ( Hungary) ( Vicián et al. 2017); Făget Basin: CoŞteiu de Sus, Lăpugiu de Sus ( Romania) (Hoernes & Auinger 1890).