Tosapusia Habe, 1964

Harzhauser, Mathias & Landau, Bernard, 2021, An overlooked diversity-the Costellariidae (Gastropoda: Neogastropoda) of the Miocene Paratethys Sea, Zootaxa 4982 (1), pp. 1-70 : 57

Genus Tosapusia Habe, 1964

Type species. Mitropifex isaoi Kuroda & Sakurai in Kuroda, 1959, by monotypy, Present-day, Indo-West Pacific.

Description. “ Shell elongate fusiform, sometimes widely fusiform or turriform, typically with high spire and long to very long siphonal canal. Suture typically canaliculated or impressed, often resulting in telescopic appearance of spire. Whorls outline varying from subcylindric to flattened or evenly convex. Axial sculpture of straight ribs strong and widely set to fine and closely set. Spiral sculpture varying from fine grooves, restricted to siphonal canal or pronounced in interspaces between axials only, to strong cords overriding axial ribs to form beads or strong gemmae at intersections. Aperture elongate, its outer lip smooth or bearing fine lirae on its inner surface. Inner lip with between three and five columellar folds, with the upmost fold being the strongest ” ( Fedosov et al., 2017: 564).

Discussion. The large and slender fusiform Mitra neudorfensis Schaffer, 1898 and Vexillum pseudocupressinum Bałuk, 1997 have been placed so far in Vexillum by Biskupič (2020) and Bałuk (1997). Alternatively, we propose a placement in Tosapusia Habe, 1964 . The genus Tosapusia differs from Vexillum especially in its longer siphonal canal, which lacks a deep notch. In addition, axial ribs in Tosapusia are typically straight, but tend to be arcuate and undulating in Vexillum ( Fedosov et al. 2017) . Tosapusia pseudocupressina is strikingly similar to the extant Indo-West Pacific Tosapusia evelynae ( Guillot de Suduiraut, 2007) in outline and both species display a comparable variability in sculpture. Tosapusia isaoi Kuroda & Sakurai in Kuroda, 1959 is a modern analogue of T. neudorfensis , but lacks a subsutural groove. Moreover, the preference for offshore settings of the two discussed Miocene species is consistent with the deep water habitat of extant Tosapusia species.

A further species from the European Neogene, which should be placed in Tosapusia , is T. cupressina ( Brocchi, 1814) from the middle Miocene to Pliocene of the proto-Mediterranean Sea ( Landau et al. 2013).

Extant Tosapusia species have an Indo-West Pacific distribution (Fedosov et al. 2007) but reached to the protoMediterranean Sea and the Central Paratethys during the Miocene. The genus persisted in the proto-Mediterranean Sea until the Pliocene, clearly postdating the Tethys closure during the early Miocene (Harzhauser et al. 2007). Therefore, our data document a restriction of the former distribution area of Tosapusia and should not be misinterpreted as immigration from the IWP region.

Key to Paratethyan Tosapusia species :

- Sculpture very fine, almost straight-sided whorls............................................. T. pseudocupressina - Prominent subsutural furrow................................................................. T. neudorfensis