Tribia partschi (Hörnes, 1854)

Harzhauser, Mathias & Landau, Bernard, 2012, A revision of the Neogene Cancellariid Gastropods of the Paratethys Sea 3472, Zootaxa 3472, pp. 1-71 : 54

Tribia partschi (Hörnes, 1854)

Figs 3X, 10E 1–E 3

Cancellaria Partschi Hörnes, 1854: 307 , pl. 34, figs 3a–b.

Cancellaria (r. Trigonostoma ) Partschi M. Hoern.— Hoernes & Auinger 1890: 278.

Cancellaria (Tribia) partschi Hörnes — Sieber 1936: 92.

Narona (Tribia) partschi (Hörnes, 1856) [sic]— Harzhauser 2002: 110, pl. 9, fig. 10.

Type material. NHM Vienna ( Austria); see below for details .

Studies and illustrated material. Figs 3X, 9E 1–E 3: specimen illustrated in Hörnes (1854, pl. 34, figs 3a–b), Gainfarn ( Austria), height: 27.5 mm, width: 14.1 mm NHMW 2009 z0098/0006 (old number: 1843/0032/0150), holotype by monotypy .

Discussion. An extremely rare species, which is superficially similar to Tribia mediangulata Sacco, 1894 . Both have comparable protoconch morphology (note that the transition from protoconch to teleoconch and the surface of the early teleoconch are abraded in the illustrated specimen). Differences are the more slender outline in T. partschi , the convex early teleoconch whorls, which lack a pronounced angulation, and the spiral sculpture, which consist of evenly spaced, regular spiral cords overrunning the axial ribs. The shoulder of T. partschi appears only on the last two teleoconch whorls and is less strongly angulated. Tribia partschi develops a weak but distinct anterior columellar fold, which is not present in T. mediangulata . A special feature of T. partschi is a slightly more prominent spiral rib on the last whorl delimiting the base. It is formed by the amalgamation of two spiral cords and is absent in T. mediangulata .

Distribution. Only known from the Paratethys, where it appears already during the latest Early Miocene and persist up to the middle Badenian.

Paratethys —Karpatian: Korneuburg Basin ( Austria: Kleinebersdorf); Badenian: Vienna Basin (Gainfarn).