Sonninia (Sonninia) falcata (Quenstedt, 1886), Haug, 1893

Sandoval, José, 2022, Sonniniidae Ammonitina, Middle Jurassic from Southern Spain: taxonomic, biostratigraphical and palaeobiogeographical analysis, Geodiversitas 44 (27), pp. 801-851 : 813

Sonninia (Sonninia) falcata (Quenstedt, 1886) [M?], ( Fig. 7F, G )

Ammonites tessonianus var. falcatus Quenstedt, 1886: 507 , pl. 63, fig. 10,?11, non fig. 9.

Ammonites tessonianus – Quenstedt 1858: 394, pl. 53, fig. 9.

Harpoceras alsaticum Haug, 1885: 677 (for above).

Sonninia falcata – Haug 1893: 288 (LT designated by Dietze et al. 2020: 68).

Sonnites alsaticus – Buckman 1924: T.A. 6, pl. 528A.

Sonninia (Sonninia?) alsatica – Westermann & Riccardi 1972: 49, text-figs 9-11 ([LT refigured], incorrectly nominated as HT for S. alsatica Haug, 1885 ), pl. 10, figs 1-7.

MATERIAL EXAMINED. — JCH.2.2 and JAC21.17.5 .

MEASUREMENTS. — See Table 3.

DESCRIPTION

Small planulate macroconchs, with moderately evolute whorls, which vary in section from rounded subquadrate to moderately subrectangular compressed with almost vertical umbilical walls, slightly rounded umbilical edges and gently convex flanks. The broad venter bears a highly prominent floored keel. On the inner whorls, observable in the specimen JCH.2.2, the keel is limited by shallow sulci. The ornament consists of prominent rectiradiate to weakly rursiradiate, slightly concave ribs, which project onto the shoulders and are most prominent at mid-flank. The ribs vary from rather dense and mostly single, to more separate, extremely prominent, often fasciculating in pairs. The inner or intermediate whorls may bear irregular lateral tubercles. The septal suture is not preserved in the Subbetic specimens.

REMARKS

Haug (1885: 677) described Harpoceras Alsaticum for Ammonites Tessonianus non d’Orbigny, 1845 (Quenstedt [1858: 294, pl. 53, fig. 9]). Later, Haug (1893: 288) indicated that this figure is incorrect, judging from the new figure of the same specimen (Quenstedt 1886: pl. 63, fig. 10). Then, the same author ( Haug 1893: 288) designated as the type (LT) of S. (S.) alsatica the specimen that he figured on pl. 10, fig. 1. Westermann & Riccardi (1972: 49, text-fig. 9), erroneously stating that the HT of S. alsatica ( Haug 1885: 677) is the specimen figured by Quenstedt (1858: pl. 53, fig. 9) and Quenstedt 1886: pl. 63, fig. 10). However, as indicated by Dietze et al. (2020: 68), this specimen is the type (LT) of S. (S.) falcata Haug, 1893 . This specimen (type of S. falcata ) is not the same as the one figured byHaug (1893: pl. 10, fig. 1) because Haug’s specimen has less dense and more radial ribbing, and a somewhat more rectangular whorl section. S. (S.) propinquans , which occurs in the same stratigraphic levels, is quite similar to S. (S.) falcata , but is larger, is usually slightly more evolute, has a more ovate-compressed whorl section, and has less prominent ribbing.

DISTRIBUTION

The type of S. (S.) falcata reportedly comes from the “Brauner Jura (Sowerbyi or Sauzei zones) of Spaichingen, Württemberg ( Westermann & Riccardi 1972; Dietze et al. 2020). In the Inferior Oolite at South Main Road Quarry, Dundry, Avon ( England) S. (S.) alsatica (maybe S. falcata ) occurs in a bed which corresponds closely to the lower or middle part of the Propinquans (Sauzei) Zone (horizons Bj-10b, B-11a and Bj-11b) ( Dietze et al. 2009). In SW Germany S. (S.) falcata occurs in the upper part of the Pinguis Subzone = Hebridica Subzone ( Dietze et al. 2008, 2011b). In Argentina, it occurs in the Sauzei Zone of Neuquén ( Westermann & Riccardi 1972). In Spain, specimens are from the Subbetic Propinquans Zone (Patella Subzone?) of Charilla (JCH) and Sierra de Alta Coloma (JAC21) sections.

Figures

FIG. 7. — A-D, Sonninia (Sonninia) propinquans (Bayle, 1878) [M]: A, JAC13.R.1, Propinquans Zone, Sierra de Alta Coloma (JAC13 section); B, D, JAC11.8.8, JAC11.8.9, Propinquans Zone, Patella Subzone, Sierra de Alta Coloma (JAC11 section); C, JAC21.16.4, Propinquans Zone, Patella Subzone, Sierra de Alta Coloma (JAC21 section); E, Sonninia (Sonninia) patella (Waagen, 1867) [M], JAC20.(7-6).5, Propinquans Zone, Patella Subzone, Caminno de Casa Blanca section; F, G, Sonninia (Sonninia) falcata Haug, 1893 [M?], non Quenstedt, 1886: F, JAC21.17.5, Propinquans Zone, Patella Subzone, Sierra de Alta Coloma (JAC21 section); G, JCH.2.2, Propinquans Zone, Charilla, Jaén province (JCH section); H-K, Sonninia (Sonninia) corrugata (J. de C. Sowerby, 1824) [M]: H, I, JAC21.12.5,