Strioterebrum subatorquata, (Boettger, 1906)

Harzhauser, Mathias & Landau, Bernard M., 2023, The auger snails (Gastropoda, Conoidea, Terebridae) of the Miocene Paratethys Sea, Zootaxa 5385 (1), pp. 1-70 : 36-38

Strioterebra subatorquata ( Boettger, 1906)

Figs 16H 1 –H 2

* Terebra (Myurella) subatorquata n. sp. — Boettger 1906: 22.

Terebra (Myurella) subatorquata Boettger —Zilch 1934: 276, pl. 22, fig. 10.

Terebra atorquata Sacco — Moisescu 1955b: 274, pl. 1, fig. 6 [non Strioterebrum atorquatum Sacco, 1891a ]. Type material. Holotype: SMF 373199 (Old number XII 2227 a), Senckenberg Museum, Frankfurt/Main, Germany, SL: 39.1 mm, MD: 5.8 mm, CoŞteiu de Sus ( Romania); Figs 16D 1 –D 2 .

Revised description. Large, very slender conical shell, of up to 17 teleoconch whorls; apical angle 14°. Protoconch unknown.Teleoconch whorls subcylindrical. Subsutural band not delimited by subsutural groove. Suture deeply incised. Sculpture of early teleoconch whorls with weakly opisthocyrt axial ribs, separated by interspaces of about equal width. Later whorls with narrow, strongly sigmoidal axial ribs. Interspaces between axial ribs widening slightly on later whorls, filled with delicate, dense spiral threads. Last whorl low, ~22% of total height, weakly convex, with 18 axial ribs. Base convex, moderately constricted. Fasciole prominent, convex, broad, adapically delimited by weak carina. Aperture narrow, pyriform, not excavated. Columella weakly excavated in adapical half. Columellar callus forming broad, thin rim, sharply delimited from base. No columellar fold. Outer lip not preserved. Siphonal canal moderately long, twisted, narrow, slightly deflected to the left, moderately deeply notched at tip. Siphonal canal moderately short, narrow, slightly deflected to the left.

Discussion. Strioterebrum subatorquata is based on a single specimen, which had survived several severe traumata, reflected in repeated shell repair on spire whorls and on the last whorl. Strioterebrum subatorquata differs from Strioterebrum exbistriatum by its very slender shell, absence of a subsutural band, narrow, sigmoidal axial ribs and weak spiral sculpture. These features are already seen on early spire whorls predating the shell repair marks. Another specimen from Lăpugiu de Sus ( Romania), identified as Terebra atorquata Sacco by Moisescu (1955b), might belong to the same species as well. It is broader, being closer to ‘normal’ Strioterebrum species and has more prominent spiral threads. More material will be needed to clarify the status of this species.

Strioterebrum atorquatum Sacco, 1891a , from the Pliocene of Italy, differs in its more close-set axial ribs and has a faintly delimited subsutural band (see Sacco 1891: pl. 2, fig. 35; Ferrero Mortara 1984: pl. 8, fig. 5).

Paleoenvironment. Unknown.

Distribution in Central Paratethys. Badenian (Middle Miocene): Făget Basin: CoŞteiu de Sus, Lăpugiu de Sus ( Romania) ( Boettger 1906; Moisescu 1955b).

Figures

FIGURE 1. Measurements for shell morphology, spire profiles and types of siphonal canals; AA: apical angle, MD: maxium diameter.

FIGURE 2. Fusoterebra terebrina (Bellardi & Michelotti, 1840). A1–A2. NHMW 1997z/0178/1787, Walbersdorf (Austria). B1–B2. NHMW 1997z/0178/1787, Walbersdorf (Austria). C1–C2. NHMW 1997z/0178/1787, Walbersdorf (Austria). D1–D2. NHMW 1846/0037/0121, Baden (Austria), lectotype of Terebra fusiformis Hörnes 1852.F. NHMW 1866/0001/1055, Forchtenau (Austria), holotype of Terebra bigranulata Hoernes & Auinger, 1880. E1–E2. NHMW 2023/0292/0001, Baden Sooss (Austria).

FIGURE 16 A–G. Strioterebrum exbistriatum Sacco 1891. A1–A2. NHMW 1854/0035/0116, Lăpugiu de Sus (Romania). B1–B2. NHMW 2010/0004/1093, Bad Vöslau (Austria). C1–C2. NHMW 1868/0001/0416, Lăpugiu de Sus (Romania). D1–D2. NHMW 1868/0001/0416, Lăpugiu de Sus (Romania). E1–E2. Holotype, NHMW 1846/0037/0120, Baden (Austria). F. NHMW 2010/0004/1090, Bad Vöslau (Austria). G. NHMW 2010/0004/1090, Bad Vöslau (Austria). H1–H2. Strioterebra subatorquata (Boettger, 1906), SMF 373199, CoŞteiu de Sus (Romania).