Altadema Kues, 2002

Nützel, Alexander & Karapunar, Baran, 2023, On Triassic Murchisonia-like gastropods-surviving the end-Permian extinction to become extinct in the Late Triassic, Acta Palaeontologica Polonica 68 (3), pp. 539-559 : 548-550

publication ID	https://doi.org/ 10.4202/app.01087.2023
persistent identifier	https://treatment.plazi.org/id/03D34B41-913E-F13D-232F-F98AE5DFFDE8
treatment provided by	Felipe
scientific name	Altadema Kues, 2002
status

Treatment

Genus Altadema Kues, 2002 View in CoL

Type species: Altadema convexa Kues, 2002 , Pennsylvanian , USA .

Remarks.—The type species of Altadema has a small, moderately high-spired largely smooth shell with strongly convex whorls; its selenizone is situated high on whorl. So far, four Pennsylvanian species have been assigned to this genus ( Kues 2002; Mazaev 2003). Herein, we place the Early Triassic species Altadema kokeni ( Wittenburg, 1908a) and Altadema hausmannae sp. nov. in Altadema . Altadema hausmannae has a broad slit-band above the periphery in mature whorls whereas Altadema kokeni ( Wittenburg, 1908a) has a sinus or selenizone high on the whorls.

The Triassic species Wannerispira shangganensis Kaim and Nützel in Kaim et al. 2010, closely resembles Altadema but has a more pronounced selenizone situated lower on the whorls.

Stratigraphicandgeographicrange.—UpperCarboniferous, USA and Russia –Lower Triassic, Italy.

Altadema hausmannae sp. nov.

Fig. 7 View Fig .

2005 Pseudomurchisonia kokeni Wittenburg, 1908 ; Nützel and Schulbert 2005: 497, fig. 16.

Zoobank LCID: urn:lsid:zoobank.org:act:CA52C5A2-AF63-458F-BBB6-AD0A705260DD

Etymology: Dedicated to Imelda M. Hausmann for her work on Triassic marine biota.

Type material: Holotype, MUSE-PAL 8176 , specimen of ca. four whorls lacking apex, with attached rock matrix . Paratypes, nine specimens: MUSE-PAL 8177–8185 .

Type locality: 750 m south of Cimirlo , near the road from Cimirlo to Busa del Vent , where road crosses creek in a narrow curve; GPS ( WGS 84 ): 46°03’50.5’’ N, 11°10’58.0’’ E; Trentino, North Italy GoogleMaps .

Type horizon: Werfen Formation, Gastropod Oolite Member, Lower Triassic, probably Dienerian/Smithian transition ( Hofmann et al. 2015).

Material.— Type material; in addition numerous specimens in rock-forming quantities.

Description.—Largest specimen comprises ca. six whorls apex missing), 4.9 mm high, 3.0 mm wide, turbiniform with variable apical angle of ca. 60–80°; whorls markedly convex, separated by distinct sutures; whorls with more or less pronounced subsutural shelf so that spire is gradate in most specimens; shell smooth (but studied specimens covered by a reddish crust of iron oxides or hydroxides that may obscure ornament if ornament was present); ramp demarcated by the adapical edge of broad selenizone; transition from ramp to lateral whorl face may be angular; selenizone situated high on the whorls; base convex with an umbilical chink; transition from whorl face to base evenly rounded.

Remarks.— Altadema hausmannae sp. nov. occurs in rock-forming quantities at its type locality ( Nützel and Schulbert 2005). Nützel and Schulbert (2005) identified this species as Pseudomurchisonia kokeni Wittenburg, 1908a (also from the Lower Triassic Werfen Formation) but a closer examination of the holotype of P. kokeni reveals that they are not conspecific (see below). Altadema kokeni has only a slight sinus, not a selenizone. Otherwise both species resemble each other closely. Altadema hausmannae differs widely from the type species Pseudomurchisonia insueta in whorl morphology and position of selenizone. The other species of Altadema ( A. convexa Kues, 2002 , A. cryptocarina Mazaev, 2003 , A. altadema Mazaev, 2003 , A. cryptocarina Mazaev, 2003 , and A. lira Mazaev, 2003 , all Pennsylvanian) are more slender and the spire is less gradate (having a larger angle between sutural shelf and outer whorl face).

Stratigraphic and geographic range.—Known from the type locality only, see above.

Kingdom	Animalia
Phylum	Mollusca
Class	Gastropoda
Family	Orthonematidae