Werfenella rectecostata ( Hauer, 1851 )

Nützel, Alexander, 2005, A new Early Triassic gastropod genus and the recovery of gastropods from the Permian / Triassic extinction, Acta Palaeontologica Polonica 50 (1), pp. 19-24 : 21-22

Werfenella rectecostata ( Hauer, 1851)

Figs. 1A–F , 2–4 .

Turbo rectecostatus sp. nov; Hauer 1851: 117, pl. 20: 10.

Turbo rectecostatus Hauer ; Wittenburg 1908: 284, pl. 5: 15.

Turbo gronensis sp. nov; Wittenburg 1908: 285, pl. 5: 17.

Turbo rectecostatus Hauer ; Frech 1912: 42, pl. 7: 6, 7.

Turbo rectecostatus Hauer ; Ogilvie−Gordon 1927: 31, pl. 3: 37a–c.

Turbo rectecostatus Hauer ; Leonardi 1935: 84, pl. 5: 16.

Turbo rectecostatus Hauer ; Haas 1953: 87.

Turbo rectecostatus Hauer ; Zapfe 1958: 156, 159.

Turbo rectecostatus Hauer ; Broglio Loriga, Masetti, D. and Neri 1983: 540, 545, pl. 49.

“ Turbo” rectecostatus Hauer ; Neri and Prosenato 1985: 91, table 1, pl. 3: 7, 8.

“ Turbo” rectecostatus Hauer ; Broglio Loriga, Neri and Posenato 1988: 127, 128, pl. 9: 19.

Turbo rectecostatus Hauer ; Boeckelmann 1988: 80, table 8.

See Diener (1926) and Kutassy (1940) for more synonymy.

Description.—Shell turbiniform, middle sized, up to 35 mm high; slightly higher than wide (a specimen of 26 mm height is 20 mm wide); whorls rapidly increasing, with two pronounced carinations; whorls between upper and lower carination concave to almost straight, parallel to whorl axis; whorls with broad subsutural slope ending at upper carination; third spiral rib on base in mature whorls; slope gentle to almost perpendicular to shell axis; whorls ornamented with numerous (up to 30 per whorl) straight axial ribs; nodules at intersection of ribs and carinae; inner lip concave, reflexed, forming moderate pseudoumbilicus; aperture wide, oblique subrectangular to oval, possibly with anterior outlet.

Discussion.— Werfenella rectecostata is one of the most abundant gastropods of the Early Triassic Werfen Formation (Alps) where it seems to be restricted to its upper members (Val Badia and Cenenighe Members). Its occurrence is almost identical with the outcrop area of the upper Werfen Formation ( Zapfe 1958). It has been reported from the Bükk and Bakony Mountains ( Hungary), East Alps ( Austria), South Alps ( Italy), North Alps ( Austria, Germany), and Western Serbia (e.g., Diener 1926; Kutassy 1940). Werfenella rectecostata forms a characteristic gastropod assemblage with the neritaemorph Natiria costata ( Münster, 1841) . Both species are relatively large when compared to other Early Triassic gastropods ( Nützel and Erwin 2002; Fraiser and Bottjer 2004). Generally, the gastropods from the Werfen Formation are badly preserved. Werfenella rectecostata is normally present as deformed steinkerns ( Fig. 1C–F ). Despite this poor preservation, Werfenella rectecostata is relatively easy to recognize because of its size, characteristic shape, and its angulate whorl profile. Commonly even steinkerns show remains of the costae. Frech (1912) illustrated unusually well−preserved specimens from the Werfen Formation of Hungary (here reproduced in Fig. 1A ). This material is not or only slightly deformed and shows the axial and nodular ornament in detail. Here, we illustrate specimens on the bedding planes of two limestone slabs (MHI 1819, 1820) from the Werfen Formation (Cencenighe Member) from Bad Radein/Redagno (Dolomites, Weisshorn) ( Figs. 2 , 3 ). This material also shows details of the strong nodular ornamentation that is not visible or only indistinct in the normal steinkern−preservation of this species ( Fig. 1C–F ). Undeformed steinkerns not only show remains of the teleoconch costae and the elongated shape of the aperture but also the purpurinid shape as can be seen in the specimen illustrated by Neri and Posenato (1985) and Broglio−Loriga et al. (1988), which is also redrawn here ( Fig. 4 ).

Figures

Fig. 1. A–F. Werfenella rectecostata from the Early Triassic (Olenekian) Werfen Formation. A. Reproduction of Frech's (1912: pl. 7: 7a–c) illustrations of exceptionally well−preserved specimens of Werfenella rectecostata from the Tirolites−Marls near Csopak (Iszkahegy, Hungary). B. Reproduction of Hauer's (1851: pl. 20: 10) original illustrations of “Turbo” rectecostatus. C–F. Werfenella rectecostata in typical preservation as more or less deformed steinkerns. Despite poor preservation species identity is strongly suggested by the characteristic shape and traces of the axial ornament. C. NHMW 1865 IX 22, Heilig Kreuz near St. Cassian, Südtirol. D. NHMW 1858 IX 3A, Heilig Kreuz near St. Cassian, Südtirol. E. NHMW 1884 D 475, Pitzberg, Südtirol. F. BMNH G 9059314A, Fachiade Monzoni. G. Chartronella? pagina Batten and Stokes, 1986, from Batten and Stokes (1986: fig. 10); this species from the Olenekian of Utah resembles Werfenella rectecostata. H. Chartronella unicostata Batten and Stokes, 1986, from Batten and Stokes (1986: fig. 8). I. Chartronella diagonata Cossmann, 1902, topotype material of the type species of Chartronella from the lowermost Jurassic (Hettangian) of France (from Gründel 1997: pl. 2: 1, 2).

Fig. 2. Limestone slab with several specimens of Werfenella rectecostata; Werfen Formation, Cencenighe Member, Bad Radein/Redgano, Italian Dolomites, Weisshorn (MHI 1819). The specimens show unusually wellpreserved shells with a pronounced nodular ornament at the carinations which cannot be seen in the steinkern−preservation which is usual for gastropods from the Werfen Formation.

Fig. 3. Limestone slab with specimens of Werfenella rectecostata and Natiria costata forming a characteristic gastropod assemblage in the Werfen Formation; Werfen Formation, Cencenighe Member, Bad Radein/Redgano, Italian Dolomite, Weisshorn (MHI 1820).

Fig. 4. Werfenella rectecostata redrawn from Neri and Posenato (1985: pl. 3: 7, 8). This relatively large and undeformed steinkern (composite mould from Val Sorda, western Dolomites, Italy) shows the purpurinid shape of Werfenella and its obliquely elongated, subrectangular aperture. The axial ornament is visible while the nodular ornament at the carinations is obscured.