Pseudomurchisonia insueta Koken, 1896

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 : 543-544

Pseudomurchisonia insueta Koken, 1896

Fig. 3 .

1896 Pseudomurchisonia insueta Koken ; Koken 1896: 86, fig. 12. 1897 Pseudomurchisonia insueta Koken ; Koken 1897: 106, fig. 31. 2021 Pseudomurchisonia insinueta [sic!] Koken; Karapunar and Nützel 2021: 52.

Material.—Teleoconch fragment, NHMW 1926/0002/0461, Carnian (Upper Triassic), Feuerkogel, Austria.

Remarks.—We illustrate a single specimen (teleoconch fragment) from the Carnian of the Feuerkogel, Austria, representing the type species Pseudomurchisonia insueta , housed at the NHMW. The spire whorls are convex with an edge low on the whorls that is reduced later on. The earliest preserved whorl has neither a sinus nor a selenizone but straight, slightly opisthocyrt growth lines. Then a sinus and eventually a selenizone develops distinctly below mid-whorl. The selenizone is flush with the whorl face and smooth with sinuous growth lines. The whorls are smooth except of comarginal furrows in some whorls. The base is strongly convex and anomphalous. The transition from whorl face to base is evenly rounded.

The present specimen agrees well with the description and illustrations of Pseudomurchisonia insueta as given by Koken (1896, 1897). The apical whorls including the protoconch and the shell microstructure are unknown. Hence the higher classification of Pseudomurchisonia is doubtful. As already noted by Karapunar and Nützel (2021) and as discussed below, Acutitomaria woehrmanni (the other species originally included in Pseudomurchisonia by Koken 1896) clearly does not represent the Pseudomurchisonia .

Stratigraphic and geographic range.—Carnian (Upper Triassic), Feuerkogel, Austria.

Figures

Fig. 3. Goniasmatid caenogastropod Pseudomurchisonia insueta Koken, 1896, Carnian, Feuerkogel, Austria. A. NHMW 1926/0002/0461, in lateral view A1), detail of spire whorls in lateral view showing lack of selenizone in adapical whorl, and beginning of selenizone in abapical whorl (A2), detail of last part of last preserved whorl with fully developed selenizone (slit-band) in lateral (A3) and apertural lateral (A4) views, detail of last preserved whorl in lateral view (A5).