Sonninia (Sonninia) corrugata (J. de C. Sowerby, 1824 )

Sandoval, José, 2022, Sonniniidae Ammonitina, Middle Jurassic from Southern Spain: taxonomic, biostratigraphical and palaeobiogeographical analysis, Geodiversitas 44 (27), pp. 801-851 : 813-814

Sonninia (Sonninia) corrugata (J. de C. Sowerby, 1824) [M] ( Fig. 7 H-K)

Ammonites corrugatus J. de C. Sowerby, 1824: 74 , pl. 451, fig. 3 (HT). — Buckman & Woodward 1908: pl. 6, figs 4a, b (HT refigured).

Sonninia corrugata – Buckman 1923: T.A. 4, pl. 412. — Hiltermann 1939: 163, pl. 11, fig. 7. — Morton 1975: 70, pl. 11, figs 4-9. — Fernández-López 1985:45, text-figs 4C, 5, pl. 8, figs 4-8. — Chandler et al. 2006: 369, fig. 4.6. — De Baets et al. 2008: 570, fig. 6a. — Metodiev 2019: 18, figs 7A-D. — Dietze et al. 2020: 66, pl. 6, figs 7, 9, pl. 12, fig. 6.

Sonninites felix – Buckman 1923: T.A. 5, pl. 428B.

Witchellia corrugata – Dorn 1935: 107, pl. 5, fig. 4. — Gillet 1937: 34, fig. 24.

MATERIAL EXAMINED. — JAC3.35.1 , JAC3.59.1 , JAC3.68.4 , JAC3.69.1 , JAC3.69.2. JAC3.70.1 , JAC3.70.4 , JAC3.70.5 , JAC3.71.5 , JAC3.71.6 , JAC3’.0.7 , JAC3’.4.4 , JAC3’.4.6 , JAC3’.4.9 , JAC3’.4.15 , JAC3’.4.20 , JAC3’.4.24 , JAC3’.4.36 , JAC3’.5.6 , JAC3’.5.7 , JAC3’.5.10 , JAC3’.5.11 , JAC3’.5.12 , JAC3’.6.13 , JAC3’.6.14 , JAC3’.6.16 , JAC3’.6.18 , JAC3’.6.19 , JAC3’.6.21 , JAC3’.6.23 , JAC3’.7.4 , JAC4.64.2 , JAC11.5.2 , JAC11.5.24 , JAC11.5.25 , JAC11.5.27 , JAC11. R.10 , JAC11. R.64 , JAC20.6.2 , JAC20.6.11 , JAC21.11.2 , JAC21.12.5 , JAC21.12.17 , JAC22.58.2 , JAC22.62.9 , JAC22.69.3 , JAC22.71.1 and JTT.F.A.

MEASUREMENTS. — See Table 4.

DESCRIPTION

Discoidal, small to medium-sized shells with moderately involute coiling. The whorl section varies throughout ontogeny. The inner whorls are subcircular to subquadrangular and slightly depressed with a broad ventral region, which has a small keel bordered by faint furrows. In the intermediate and outer whorls, the section becomes progressively ogival and compressed whereas the flanks become subparallel in the lower half, and convex and converging towards the ventral area in the outer half. The maximum whorl width is reached near the umbilical edge, which is rounded, and the umbilical wall is vertical. From the intermediate whorls, the external region and the ventrolateral edges are no longer differentiated and the keel is high and narrow, with no lateral grooves. The innermost whorls are smooth, and small tubercles can be differentiated only in the end part of the second whorl of some specimens. The intermediate whorls, from 10 to 15 mm in diameter, have ribs, which emerge from the coiling suture. These are flexuous, subradial or only slightly proverse, with irregular relief, and fasciculate in 2 or 3 from a small thickening located near the umbilical edge, and they curve forward in the external region. In the outer whorls, the ribbing progressively fades and the end of the BC of adult specimens can be completely smooth. The septal suture, only partially preserved in Subbetic specimens, is complex with long and highly branched L and slightly retracted umbilical lobe.

REMARKS

As indicated by Fernández-López (1985: 49), the interpretation of S. (S.) corrugata sharply contrasts among various authors. Regarding the uncertainty surrounding the nature of the HT, such as it degree of maturity, of whether it is a macro- or microconch, Chandler et al. (2006: 369) proposed that it might be best to set the species aside as a taxon dubium within the framework of precision of current ammonite taxonomy. However, the species is accepted here for small specimens that have a high and narrow keel, well-marked ribs on inner and middle whorls, and a notably reduced tuberculate stage. The specimen figured as Sonninites felix Buckman, 1923 (Buckman 1923: T.A. 5, pl. 428B) is so similar to HT of S. (S.) corrugata for both coiling, whorl section, and ornamentation that it is included here in this species.

DISTRIBUTION

According to Chandler et al. (2006: 369), the type of S. (S.) corrugata was confidently assigned to the undivided ‘Brown Ironshot’ by Buckman ( Buckman & Wilson 1896; Buckman 1923: T.A. 4, pl. 412 only, ‘topotype’; Parsons 1979). However, re-examination by Chandler of the specimen in the Natural History Museum (London) suggests that it may have come from somewhat lower down, from a part of the White Ironshot, Trigonalis Subzone. The species has been frequently cited from the Laeviuscula and Propinquans (Sauzei) zones of many Tethyan localities ( Dorn 1935; Gillet 1937; Hiltermann 1939; Oechsle 1958; Morton 1975; Fernández-López 1985; Seyed-Emami 1988; Sadki 1996; Chandler et al. 2006; De Baets et al. 2008; Metodiev 2019, etc.). The Subbetic specimens extend from Laeviuscula Zone (Trigonalis Subzone) to lower part of the Propinquans Zone, being abundant mainly in Sierra de Alta Coloma area, (sections JAC3, JAC3’, JAC4, JAC11, JAC20, JAC21 & JAC22), Campillo de Arenas, and Noalejo (Jaén Province).

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,