Pseudotuba Harzhauser & Landau 2023, nov. gen.
Creators: name: Harzhauser, Mathias
name: Landau, Bernard
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Heterostropha
Mathildidae
Pseudotuba

description: Genus Pseudotuba nov. gen.
Type species. Pseudotuba badensis (Sacco, 1895), Middle Miocene, Central Paratethys Sea.
Diagnosis. Medium-sized, solid, turbiniform shell, with strongly convex whorls and slightly gradate spire; Protoconch hyperstrophic. First teleoconch whorl with six narrow, close-set, convex spiral cords crossed by numerous much weaker axial lamellae. Last whorl globular.
Description. Medium-sized, solid, turbiniform shell, with strongly convex whorls and slightly gradate spire. Protoconch hyperstrophic. Teleoconch of convex whorls with deeply incised suture. Rounded periphery at about one-third whorl height. First teleoconch whorl with six narrow, close-set, convex spiral cords crossed by numerous much weaker, prosocline axial lamellae forming fine, dense cancellate pattern, with small, rounded beads at intersections. Secondary spiral cords intercalated between primary cords on later whorls. Last whorl globular, with numerous spiral cords of subequal strength and spacing; base not or weakly delimited, convex, umbilicus relatively broad to narrow, delimited by periumbilical cord in some species. Aperture subcircular. Columella concave with broad rim. Umbilicus narrow or reduced to chink. No parietal callus. Outer lip thin. Spiral lirae within aperture in some species.
Etymology. Prefix pseudo - (from Greek ψευδής, false).
Included species. Cyclostoma cancellata Grateloup, 1828 (Langhian, France) (Cossmann & Peyrot 1922: 179, pl. 3, figs 35–36, Figs 30F 1 –F 4). Tuba sulcata sensu Sacco, 1895 (Langhian, Colli Torinesi, Italy) (Sacco 1895: pl. 3, fig. 43); Tuba pedemontana Sacco, 1895 (Burdigalian/Langhian, Colli Torinesi, Italy) (Sacco 1895: pl. 3, fig. 45); Turbo bellardii d’Orbigny, 1852 (Tortonian, Po Basin, Italy) (Sacco 1895: pl. 3, fig. 46). Littorina cyclostomoides Deshayes, 1861 (Eocene, Paris Basin, France) (Deshayes 1861: pl. 16 figs 1–4) (own material studied). Tuba elatospira Cossmann, 1907 (Eocene, Paris Basin, France, (Cossmann 1907: pl. 8 fig. 129–3). Turbo sculptus J. de C. Sowerby, 1823 (Eocene, UK) (Sowerby 1823: pl. 395 fig. 2)
Stratigraphic and geographic range. The genus was present already during the Eocene, when it was represented by several species in the Paris Basin. During the Miocene, Pseudotuba was represented in the entire circum-Mediterranean region, including the North Sea Basin. We are not aware of Pliocene occurrences. ‘ Tuba’ seriaformis Schr̂der, 1995, from the Early Cretaceous of Poland, is already quite close to Pseudotuba and develops a hyperstrophic protoconch and six spiral cords on the first teleoconch whorl (see Kaim 2004: fig. 117). However, due to the huge stratigraphic gap we refrain from including this species in Pseudotuba.
Paleoenvironment. The type species was found in middle to outer neritic depositional environments.
Discussion. Species placed herein in the genus Pseudotuba nov. gen. have been placed so far in Tuba I. Lea, 1833 [type species Tuba alternata I. Lea, 1833, by subsequent designation, Cossmann, 1912: 13, Eocene, Western Atlantic (see https://science.mnhn.fr/institution/mnhn/collection/f/item/j05056?listIndex=9&listCount=76 for specimens of the type species)]. Synonyms of Tuba are: Gegania Jeffreys, 1884, type species Gegania pinguis Jeffreys, 1884, by monotypy. Present day, Eastern Atlantic; Kaitangata Finlay & Marwick, 1937, type species Kaitangata hendersoni Finlay & Marwick, 1937, by original designation. Paleocene. New Zealand; Tubena Marwick, 1943, type species Gegania (Tubena) viola Marwick, 1943; original designation by Marwick (1943: 188). Miocene, New Zealand.
In his revised diagnosis of Tuba, Bieler (1995: 627) stated: “ Teleoconch […] periphery and base rounded (juveniles with double keel) […] 1 or 2 of the main spiral ribs markedly more prominent than the others; […] upper point of attachment of the following whorl at a spiral rib less prominent than at least one of the exposed ribs above; this attachment rib, with an additional rib next to it, forming a distinct double edge at outer shell base.” The two more prominent primary spiral cords correspond to S2 and S 3 in Mathildidae and give the early whorls a somewhat angulated profile. In contrast, Pseudotuba develops six primary cords that are present from the teleoconch/protoconch boundary and are not, or hardly, differentiated. Thus, the early whorls are not angulated. In addition, the base of Pseudotuba is rounded and lacks a “ double edge ”. Lastly, Pseudotuba has a hyperstrophic rather than heterostrophic protoconch. In our opinion, the consistent difference in the protoconch and different number and development of the primary cords on the early whorls calls into question a close relation between Pseudotuba and Tuba and Mathilda.
Fossil species of Tuba. Currently, MolluscaBase eds. (2023) lists 16 fossil and extant species in Tuba. Along with the type species of Gegania, Tuba pinguis (Jeffreys, 1884), the Recent Tuba valkyrie (Powell, 1971), T. fuscocincta Bieler, 1995, T. jeffreysi (Dall, 1889) and T. kiiensis (T. Nakayama, 2000), represent species with differentiated spiral cords on early teleoconch whorls. Of the fossil species, along with the type species T. alternata I. Lea, 1833 (Eocene, USA), we retain T. hendersoni (Finlay & Marwick, 1937) (Paleocene, New Zealand), T. olsoni (P. A. Maxwell, 1969) (Eocene, New Zealand) and T. viola (Marwick, 1943) (Miocene, New Zealand) in Tuba. In addition, T. striata I. Lea, 1833 and T. antiquata (Conrad, 1833), both from the Eocene of the USA, and Tuba peruviana Olsson, 1930 (Eocene, Peru) are placed in Tuba herein. Tuba antarctodema (Stilwell & Zinsmeister, 1992) and T. austroconvexa (Stilwell & Zinsmeister, 1992), might be two additional Tuba species, documented from the Eocene of Antarctica, but we have not seen specimens. Oligocene and Miocene Tuba species from the Proto-Mediterraean Sea are: Tuba alternicincta Sacco, 1895 (Rupelian, Colli Torinesi, Italy) (Sacco 1895: pl. 3, fig. 44); Tuba miocaenica (Sacco, 1895) (Langhian, Colli Torinesi, Italy) (Sacco 1895: pl. 3, figs 48–50; Ferrero Mortara et al. 1984; pl. 41, figs 7, 9); Tuba percingulata (Sacco, 1895) (Burdigalian, Colli Torinesi, Italy) (Sacco 1895: pl. 3, fig. 51). A further undescribed species of Pseudotuba from the Upper Miocene Tortonian of Cacela Velha, southern Portugal, is present in the NHMW coll. (ex. BL coll.) that closes the geographic gap between the Miocene French Atlantic and Proto-Mediterranean occurrences.
‘Gegania’ kuteiana (Beets, 1942), from the Miocene of Borneo, should be excluded from Mathildidae and might rather represent a Cerithioderma (Capulidae) (see Beets 1942; pl. 16, figs 21–23). Similarly, Tuba acutissima W.H. Dall, 1892, from the Miocene of Florida, should be excluded from Mathildidae, due to its non-heterostrophic protoconch (see Dall 1892: pl. 18, fig. 4a).
Tuba might have appeared already during the Late Cretaceous and is documented by numerous species; e.g., Gegania vibrayeana d’Orbigny 1843 (France), Tuba bella Conrad, 1860 (USA), Tuba parabella Wade, 1926 (USA), Tuba manzaneti Stephenson, 1941 (USA), Gegania mississippiensis Dockery, 1993. The placement of these species in Tuba, however, will need verification because they represent large and solid shells with conical spires, partly with nearly turreted early teleoconch whorls (e.g., Kollmann 2005: pl. 17 figs 11a–b, https://science.mnhn.fr/institution/ mnhn/collection/f/item/s07143?listIndex=8&listCount=19). The depositional setting of most of these species seems to have been shallow marine.
description: Published as part of Harzhauser, Mathias & Landau, Bernard, 2023, The Architectonicidae and Mathildidae (Gastropoda, Heterobranchia) of the Miocene Paratethys Sea-victims of the Miocene Climatic Transition, pp. 1-74 in Zootaxa 5370 (1) on pages 57-58, DOI: 10.11646/zootaxa.5370.1.1, http://zenodo.org/record/10147814