Proacirsa Cossmann, 1912

Gründel, Joachim & Nützel, Alexander, 2013, Evolution and classification of Mesozoic mathildoid gastropods, Acta Palaeontologica Polonica 58 (4), pp. 803-826 : 814

Genus Proacirsa Cossmann, 1912

Fig. 7B, C .

Type species.— Turritella inornata Terquem and Jourdy, 1871 , original designation; Bathonian ; France .

Included species: Cerithium laevigatum Eudes−Deslongchamps, 1843 , Bajocian; Cerithium januale Trautschold, 1860 , Pliensbachian (?); Chemnitzia dilatata Laube, 1867 , Callovian (?); Turritella similis Moore, 1867 , Pliensbachian; Turritella inornata Terquem and Jourdy, 1871 , Bathonian; Chemnitzia struvii Lahusen, 1883 , Callovian–Oxfordian; Cerithium semiornatum Greppin, 1888 , Bathonian; Zygopleura (Anoptychia) bigoti Cossmann, 1913 , Pliensbachian; Hudlestoniella lahuseni Gerasimov, 1962 , Tithonian–Berriasian; Turrithilda zlotniki Kaim, 2004 , Valanginian; Proacirsa sp. , cf. struvii ( Lahusen, 1883) sensu Gründel 2005a , Callovian.

Emended diagnosis.—The protoconch consists of about 1.5 whorls, is heterostrophic and almost coaxial. The early teleoconch has two or three spiral ribs; the adapical rib is distinctly weaker than the abapical spiral ribs. The spiral ribs are intersected by numerous axial ribs; the intersections are more or less nodular. After a few teleoconch whorls, the ornament fades. Only in some cases, remains of a spiral ornament are present on the last whorls. The base is moderately convex and is ornamented with broad spiral ribs.

Remarks.—The protoconch of a species belonging to Proacirsa was described by Gründel (2005b).

Stratigraphic and geographic range.—Pliensbachian to Valanginian, Early Cretaceous; Germany, England, France, Luxembourg, Switzerland, Poland, Russia.

Figures

Fig. 7. Type species and examples for Triassic and Jurassic genera of the family Gordenellidae. A. Camponella pianozensis (Zardini, 1985), Cassian Formation, S Tyrol, Italy, Late Triassic; from Bandel (1995: pl. 8: 7). B. Proacirsa sp., cf. struvii (Lahusen, 1883), Dubki near Saratov, Russia, late Callovian; from Gründel (2005: pl. 5: 12, 16). Whole specimen (B1), protoconch (B2). C. Proacirsa laevigata (Eudes−Deslongchamps, 1843), erratic boulder from Bauer−Wehrland, Germany, Callovian; from Gründel (2000: pl. 1: 15). D. Schafbergia crenata (Stoliczka, 1861), Schafberg near St. Wolfgang, Austria, late Pliensbachian; from Szabó (2008: fig. 87B).