Caenogastropoda Cox, 1960

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 : 540-543

Subclass Caenogastropoda Cox in Knight et al., 1960

Family Goniasmatidae Nützel and Bandel, 2000 Included genera: Laschmaspira Mazaev, 2003 , and Altadema Kues, 2002 ; these genera have been placed in Orthonematidae . However, they clearly possess a selenizone and hence they are placed in Goniasmatidae . Pseudomurchisonia Koken, 1896 , has only a weak sinus in the upper whorl portion; it is possible that it would develop into a selenizone. Therefore, it is tentatively placed in Goniasmatidae . Murchisonietta Nützel, Kaim, and Grădinaru, 2018 , a subjective younger synonym of Wortheniopsis Böhm, 1895 , has also been placed tentatively in Goniasmatidae ( Nützel et al. 2018) .

Genus Laschmaspira Mazaev, 2003

Type species: Laschmaspira rara Mazaev, 2003 , Pennsylvanian , Russia .

Remarks.—To date, Laschmaspira has been known only from a few Pennsylvanian and Permian species ( Mazaev 2003). Here we place two Late Triassic species in this genus: Laschmaspira euglypha Koken, 1896 comb. nov. (previously Murchisonia euglypha Koken, 1896 ), and Laschmaspira lirata sp. nov., both from the Feuerkogel, Austria. Laschmaspira lirata sp. nov. and the type species of Laschmaspira have a spiral ornament on the teleoconch whorls. However, Laschmaspira euglypha Koken, 1896 , seems to lack spiral ornament.

Stratigraphic and geographic range.—Permian (Asselian) of Southern Fergana ( Uzbekistan), middle Carboniferous of Central Russia – Carnian (Upper Triassic).

Laschmaspira lirata sp. nov.

Figs. 1 , 2 .

Zoobank LCID: urn:lsid:zoobank.org:act:361FE73E-A4F1-4E81-A9A2-042103EE645F

Etymology: From Latin lirata , ridged; for the spiral lirae on the teleoconch,

Type material: Holotype, NHMW 2023 /0080/0001, well preserved shell with protoconch . Paratypes, NHMW 2023 /0080/0002–0007, well preserved shells.All from the typical Hallstatt Limestone facies, calcite pseudomorphoses covered by a reddish stain of ferruginous material .

Type locality: Feuerkogel , south slope, near Röthelstein und Tellschen, near Kainisch, Steiermark, Austria .

Type horizon: Hallstatt Limestone , Carnian (Upper Triassic) .

Material.— Type material only.

Description.—Shell high-spired; holotype consists of about 9 whorls, 15.4 mm high, 7.9 mm wide; first four whorls smooth, convex, dome-shaped with an apical angle of 70–80°; initial whorl 0.33–0.36 mm wide; clear ontogenetic boundaries (embryonic/larval/teleoconch) not visible due to preservation or possibly gradual; later teleoconch with an apical angle of ca. 30°; teleoconch whorls markedly convex, angulated at borders of selenizone, with a broad ramp; selenizone forming from third whorl onwards as an increasingly deepening sinus of growth lines; selenizone on mature whorls broad, concave with lunulae of dense, distinct growth lines; late teleoconch whorls with numerous, distinct spiral lirae above and below selenizone; suture deep; base convex, anomphalous, demarcated from whorl face by an angulation, with numerous spiral threads.

Remarks.—The most similar Triassic species is Laschmaspira euglypha ( Koken, 1896) , from the same locality (Feuerkogel). However, this species lacks spiral ornament, its whorls are more angulated, and the selenizone starts after the first whorl according to Koken (1896, 1897). Laschmaspira lirata sp. nov. exhibits a marked ontogenetic change regarding apical angle and ornament from broad, smooth, slitless initial whorls to ornamented much more slender and slit-bearing later whorls. However, a clear indication of a larval shell of the planktotrophic type could not be found. The size of the initial whorl (>0.3 mm) is rather large and suggests non-planktotrophic larval development (see Nützel 2014). Laschmaspira lirata sp. nov. can be regarded as a descendant of Paleozoic Goniasmatidae . The Permian Goniasma gerasimovi Mazaev, 2019 , resembles Laschmaspira lirata sp. nov. in having an ornament of numerous spiral lirae which is otherwise unusual for Goniasma . However, G. gerasimovi differs in having a submedian angulation as is typical for Goniasma .

Stratigraphic and geographic range.— Type horizon and locality only.

Genus Pseudomurchisonia Koken, 1896

Type species: Pseudomurchisonia insueta Koken, 1896 , Austria, Norian (Upper Triassic); subsequent designation by Cossmann (1897).

Remarks.— Pseudomurchisonia was tentatively placed in Purpurinidae (Caenogastropoda) by Wenz (1939: 526) who erroneously considered P. woehrmanni Koken, 1896 , to be the type species. Thus, the genus was not included in the Treatise ( Knight et al. 1960) which covered only few caenogastropods. Both originally included species, Pseudomurchisonia insueta Koken, 1896 , and P. woehrmanni Koken, 1896 , come from the Carnian (Upper Triassic) of the Feuerkogel in Austria. Both are moderately high-spired and have a broad selenizone that appears late during ontogeny. Apart from the two originally included species, two Early Triassic species were placed in Pseudomurchisonia : P. extracta ( Berger, 1860) and P.? sundaica Krumbeck, 1924, but none from the Paleozoic and the post-Triassic.

The type species Pseudomurchisonia insueta (see below) differs from Goniasma in lacking an angulation, but resembles this genus in having a selenizone low on the whorls and lacking strong ornament. We therefore place this genus tentatively in Goniasmatidae . More knowledge about the early ontogeny of Pseudomurchisonia insueta is needed for a better substantiated systematic placement of this genus.

Pseudomurchisonia extracta ( Berger, 1860) (originally placed in Natica ) is based on an obviously poorly preserved specimen (probably a steinkern) from the Schaumkalk, a lithological unit of the Muschelkalk in the German Basin. The type is therefore of Anisian age. It shows a markedly gradate spire with a ramp bordered by an edge high on the whorls. This species has been placed in Pseudomurchisonia by Wittenburg (1908a: 284, pl. 5: 7) who illustrated a specimen with evenly rounded whorls and a median selenizone from the Werfen Formation of the Valsugana, Italy. Wittenburg’s (1908a) specimen is certainly not conspecific with Bergers’s (1860) type specimen. The Early Triassic specimen reported by Wittenburg (1908a) could either be a member of Pleurotomariida or Goniasmatidae . Baumgarte and Schulz (1986) and Kramm (2004) placed Pseudomurchisoni extracta in Angularia ; their illustration of specimens from Hessen indicates that this assignment is more correct. Pseudomurchisonia extracta is probably a nomen dubium but its type specimens must be studied.

Pleurotomaria triadica Benecke, 1868 , and Pleurotomaria euomphala Benecke, 1868 , from the Lower Triassic of Mount Zacon at Borgo Valsugana ( Italy) were placed in Pseudomurchisonia by Wittenburg (1908b), but need re-study of the types for confirmation.

Pseudomurchisonia schmidti Wittenburg, 1908b , is a nomen nudum.

Pseudomurchisonia ? sundaica Krumbeck, 1924, from the Lower Triassic is actually close to the type species Pseudomurchisonia insueta Koken, 1896 , and could be congeneric.

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

Figures

Fig. 1. Goniasmatid caenogastropod Laschmaspira lirata sp. nov., Carnian, Feuerkogel, Austria. A. NHMW 2023/0080/0001, holotype, in lateral view (A1), detail of last whorls in lateral view (A2), detail adapical whorl face with spiral lirae in lateral view (A3), detail selenizone (slit-band) in lateral view (A4), detail of whorl face and base of last whorl with spiral lirae in lateral view (A5), early whorls in lateral view (A6, A7), early whorls in oblique lateral view (A8, A 9), detail of early whorls in oblique lateral view showing beginning of selenizone as a sinus (A10), early whorls in apical view (A11).

Fig. 2. Goniasmatid caenogastropod Laschmaspira lirata sp. nov., Carnian, Feuerkogel, Austria. A. NHMW 2023/0080/0002, paratype, in lateral view A1), early whorls in lateral (A2), oblique lateral (A3), and apical (A4,A5) views.B. NHMW 2023/0080/0003, paratype, in lateral view (B1), detail of whorl face with selenizone (slit-band) and ornamentation of spiral lirae in oblique lateral (B2) and lateral (B3) views.