Pustulosia, Harzhauser & Guzhov & Landau, 2023

Harzhauser, Mathias, Guzhov, Aleksandr & Landau, Bernard, 2023, A revision and nomenclator of the Cainozoic mudwhelks (Mollusca: Caenogastropoda: Batillariidae, Potamididae) of the Paratethys Sea (Europe, Asia), Zootaxa 5272 (1), pp. 1-241 : 153-154

Pustulosia nov. gen.

Type species. Cerithium submitrale Eichwald, 1851 ; Middle Miocene , Badenian (Serravallian), Ukraine, Central Paratethys Sea .

Etymology. Referring to the pustulose beads.

Diagnosis. Medium sized, slender to moderately slender with subcylindrical teleoconch whorls. Early teleoconch whorls with two weak spiral cords and slight angulation above abapical suture. Later teleoconch whorls with markedly bipartite sculpture of two spiral rows of large, rounded beads, typically axially arranged. Granulae or lamellae occasionally present on inner surface of aperture. Differing from similar genera, such as Granulolabium , in its bipartite sculpture of the early teleoconch.

Description. Medium sized, slender to moderately slender of about eleven teleoconch whorls. Protoconch unknown. Early teleoconch whorls conical with mid-whorl spiral cord and second spiral cord just above abapical suture, coinciding with weakly angulated periphery.Abapically, sculpture of two spiral rows of large, rounded beads; a third cord may appear at abapical suture, highly variable in strength. Beads usually aligned axially, moderately wide-spaced, not crowded. Secondary spiral cords frequently developed, rarely attaining strength of primary cords. Whorl profile subcylindrical with narrowly incised, undulating suture. Last whorl weakly convex with moderately constricted base. Base convex with prominent spiral cords. Aperture ovate to subcircular; outer lip not thickened, often weakly expanded abapically, with shallowly opisthocyrt growth lines, granulae or short lirae occasionally present within; anal canal moderately incised; siphonal canal short, moderately wide, slightly deflected to the left. Columella strongly excavated in adapical half, convex and slightly twisted below. Columellar callus forming broad rim. No characteristic color pattern preserved.

Stratigraphic and geographic range. The genus appeared during the Eggenburgian (early Burdigalian) in the Central Paratethys and persisted there until the late Badenian (Serravallian). During the Chokrakian (Langhian) it was also present in the Eastern Paratethys. Proto-Mediterranean records derive from the Langhian of Spain ( Aguilà & García García 1997) and the Serravallian of Turkey ( Landau et al. 2013). We are not aware of records from the northeastern Atlantic.

Included species. Cerithium hornense Schaffer, 1912 (Eggenburgian) , Cerithium submitrale Eichwald, 1851 (Badenian) .

Ecology. Both species placed in Pustulosia are found in mud-flat deposits, often associated with Terebralia , e.g. Pustulosia hornensis at Mold ( Austria) and P. submitralis at Ritzing ( Austria) and St. Veit ( Austria) (own data).

Discussion. Pustulosia is reminiscent of Burdigalian morphs of Granulolabium plicatum from the northeastern Atlantic with bipartite sculpture (see Fig. 25F) and the rare presence of granulae or lirae inside the aperture might suggest a close relation at first sight. The granulae inside the aperture, however, are a problematic character for phylogenetic conclusions because only very few specimens of Pustulosia show this feature. Thus, we consider this similarity to represent a case of convergence. Similarly, even morphs of Granulolabium plicatum with bipartite sculpture on late teleoconch whorls develop a tripartite sculpture on early teleoconch whorls with three spiral cords of equal strength and beads, which develop on top of these cords ( Fig. 26J). In Pustulosia , in contrast, early teleoconch whorls have a strictly bipartite sculpture and beads form without underlying spiral cords (Figs 33G– H). The sculpture of early teleoconch whorls also allows a separation from Tiaracerithium Sacco, 1895 , which has striate sculpture on earliest whorls and a dominant adapical spiral cord on subsequent whorls ( Figs. 30M–N). Tiarapirenella Sacco, 1895 differs in its pyriform outline, higher last whorl, and intense color pattern.

Species-level taxa placed in Pustulosia reported from the Paratethys aspera . Pirenella . Švagrovský, 1982 → Pustulosia submitralis ( Eichwald, 1851) bicostata. Cerithium . Eichwald, 1851 → Pustulosia submitralis ( Eichwald, 1851) borsodensis . Potamides Schréter, 1929 → Pustulosia submitralis ( Eichwald, 1851) costulata. Cerithium . Handmann, 1883a → Pustulosia submitralis ( Eichwald, 1851) eichwaldi . Cerithium . Hilber, 1882 → Pustulosia submitralis ( Eichwald, 1851) haeutlingense. Granulolabium . Pfister & Weg., 2007 → Pustulosia hornensis ( Schaffer, 1912) hornense . Cerithium . Schaffer, 1912 → Pustulosia hornensis ( Schaffer, 1912) melanopsiformis . Potamides . Friedberg, 1914 → Pustulosia submitralis ( Eichwald, 1851) nodosoplicatum . Cerithium . Ĥrnes, 1855 [pars] → Pustulosia submitralis ( Eichwald, 1851) petersi . Potamides . Friedberg, 1914 → Pustulosia submitralis ( Eichwald, 1851) schaueri . Cerithium . Hilber, 1882 → Pustulosia submitralis ( Eichwald, 1851) submitrale . Cerithium . Eichwald 1851 → Pustulosia submitralis ( Eichwald, 1851) vitense . Cerithium . Handmann, 1883a → Pustulosia submitralis ( Eichwald, 1851)