Fraudiziba, Harzhauser & Landau, 2021

Harzhauser, Mathias & Landau, Bernard, 2021, The Mitridae (Gastropoda: Neogastropoda) of the Miocene Paratethys Sea, Zootaxa 4983 (3), pp. 1-72 : 33-34

Genus Fraudiziba nov. gen.

Type species. Ziba paratethyca nov. nom., original designation herein. Middle Miocene, Paratethys Sea.

Etymology. A combination of the Latin fraus (= fraud) and Ziba .

Diagnosis. Medium-sized, moderately slender to moderately broad fusiform shell with paucispiral protoconch and smooth early teleoconch whorls. Teleoconch whorls subcylindrical with rounded or angulated shoulder. Spiral sculpture of flat spiral cords separated by narrow, partly punctate spiral grooves. Characterized by colour pattern of large subquadrate dots on shoulder and spiral rows of dots and/or dashes on last whorl.

Description. Shell medium-sized, moderately slender to moderately broad fusiform. Protoconch unknown in Paratethyan species but paucispiral of 1.25 smooth whorls in Fraudiziba ottomanica nov. sp. Teleoconch of nine whorls. Early teleoconch whorls smooth, subcylindrical with incised to faintly canaliculate suture. Rounded or angulated shoulder develops between fourth to sixth teleoconch whorls. Last whorl moderately high, subcylindrical, slowly contracting. Sculpture of flat spiral cords typically on and close below shoulder, separated by delicate or distinct, partly punctate spiral grooves, partly to fully reduced in some species. Base and fasciole covered by flat, often bifid spiral cords. Aperture moderately narrow, posteriorly angulated with indistinct anal canal. Columellar callus narrow, restricted to area between adapical columellar fold to tip of siphonal canal. Columella with four columellar folds, abapically decreasing in width; fifth abapical fold weakly developed in some specimens. Siphonal canal moderately long, straight to slightly bent to the left, with moderately deep siphonal notch. Colour pattern consisting of large subquadrate dots on shoulder in most species and spiral rows of small or large dots and/or dashes below shoulder.

Stratigraphic and geographic range. The oldest records of this genus are Fraudiziba protensa (Bellardi, 1887) , from the Burdigalian of the Proto-Mediterranean Sea ( Bellardi 1887b), and F. paratethyca nov. nom. from the Karpatian (= late Burdigalian) of the Central Paratethys Sea ( Harzhauser 2002). An early Miocene occurrence from the north-eastern Atlantic is cited by Peyrot (1928). The genus is widespread during the middle Miocene, documented by several species from the north-eastern Atlantic, the Proto-Mediterranean Sea and the Central Paratethys ( Peyrot 1928; Landau et al. 2013). Fraudiziba has its last optimum during the Tortonian in the Proto-Mediterranean Sea. Its last occurrence is in the Pliocene, represented by a single species, F. concava (Bellardi, 1997) ( Malatesta 1974; Chirli 2002).

Included species. Fraudiziba paratethyca nov. nom., Fraudiziba ottomanica nov. nom., Mitra concava Bellardi, 1887 , Mitra goniophora Bellardi, 1850 , Mitra goniophora sensu Peyrot, 1928 , Mitra goniophora perangulata Peyrot, 1928 , Mitra protensa Bellardi, 1887 , Mitra protracta Bellardi, 1887 , Mitra scalarata Bellardi, 1850 , Mitra scalarata posticoangulosa Sacco, 1904 , Mitra scalarata subiriensis Sacco, 1904 , Mitra subcarinata Bellardi, 1887 , Mitraria (Mitraria) mathiasi Bałuk, 1997 , Mitraria (Mitraria) rudolfi Bałuk, 1997 . All other Neogene European taxa listed by Cernohorsky (1991) as ‘ Ziba ’ are excluded from Fraudiziba .

Palaeoenvironment. Inner to middle neritic settings, ranging from silty-sandy environments with sea grass to pelitic bottoms in up to 250 m water depth.

Discussion. Fraudiziba is superficially similar to the extant West African Ziba H. Adams & A. Adams, 1853 (type species Mitra carinata Swainson, 1824 , by subsequent designation by Wenz (1943: 1292). Therefore, Glibert (1960) and Cernohorsky (1991) listed the Miocene European species of Fraudiziba as Ziba [note that based on molecular data, Cernohorsky’s concept of Ziba is not supported, as most extant species listed by Cernohorsky (1991) as Ziba were placed in Imbricaria and Subcancilla by Fedosov et al. (2018)]. Fraudiziba differs from Ziba in several aspects. The protoconch of Ziba comprises two to three moderately convex whorls ( Simone & Turner 2010; Fedosov et al. 2018), whereas the protoconch of Fraudiziba is paucispiral, of about 1.25, nearly straight-sided whorls [based on Ziba ottomanica nov. sp.]. Early teleoconch whorls of all extant Ziba species have cancellate sculpture, but are completely smooth in Fraudiziba . The columellar callus of Fraudiziba is restricted to the area between the adapical columellar fold to the tip of the siphonal canal, whereas it extends to the parietal region in Ziba . Moreover, the last whorl of Ziba is higher and more slender. Finally, the colour pattern of Fraudiziba consist of broad subquadrate dots on the shoulder and spiral row of large or small dots and/or dashes, whereas all extant Ziba species are monochrome.

The colour pattern of Fraudiziba is reminiscent of that of the extant Indo-West Pacific Imbricaria astyagis ( Dohrn, 1860) and Imbricaria fulgetrum ( Reeve, 1844) . A placement in Imbricaria Schumacher, 1817 , however, is unlikely based on the obconical shell base, the prominent spiral cords on early teleoconch whorls and delicate axial riblets between the spiral cords of Imbricaria species (see Fedosov et al. 2018). Subcancilla Olsson & Harbison, 1953 may be similar in profile, but differs in its prominent sharp-crested spiral cords.

Key to Fraudiziba nov. gen. species in the Paratethys

1. Spiral sculpture restricted to base and siphonal fasciole.................................... F. paratethyca nov. nom. Spiral sculpture present above base........................................................................2

2. Shell relatively broad, shoulder indistinct............................................................ F. rudolfi Shell narrower fusiform, shoulder angled or roundly angled.....................................................3

3. Shoulder roundly angled, spiral sculpture weak and close-set.......................................... .. F. mathiasi Shoulder sharp, distinct spiral grooves obsolete mid-whorl.......................................... F. subcarinata