Witchellia connata (Buckman, 1927)

Sandoval, José, 2022, Sonniniidae Ammonitina, Middle Jurassic from Southern Spain: taxonomic, biostratigraphical and palaeobiogeographical analysis, Geodiversitas 44 (27), pp. 801-851 : 826

Witchellia connata (Buckman, 1927) [M] ( Fig. 10 B-E)

Zugella connata Buckman, 1927 : T.A. 7, pl. 750, figs 1-3 (HT).

Witchellia connata – Imlay 1973: 69, pl. 20, fig. 4, pl. 21, figs 1-7, 10, 11. — Fernández-López 1985: 82, pl. 6, fig. 2. — Sadki 1996: 173, pl. 4, fig. 7. — Seyed-Emami et al. 2000: 258, figs 3/2-3. — Ohmert 2004: 49, text-figs 8, 9, pl. 12, figs 1-9.

Witchellia aff. connata [M] – Dietze et al. 2003: 9, pl. 1, fig. 2.

Witchellia connata [M] – Dietze et al. 2007: 6, figs 3a-d. — Dietze et al. 2019: 58, figs 4(4, 6).

MATERIAL EXAMINED. — JAC3.19.3 , JAC3.20.10 , JAC3.33.1 , JAC3.33.2 , JAC11.5.6 , JAC11.5.32 , JAC11. R.19 , JAC11. R.26 , JAC22.40.1 , JAC22.40.2 , JVM.26 , JVM.31 , JVM.32 , JVM.33 and JVM.34 .

MEASUREMENTS. — See Table 12.

DESCRIPTION

Medium-sized discoidal shells, compressed with moderately evolute coiling. The whorl section is subrectangular, with a flat and sloping umbilical wall, rounded umbilical edge, weakly convex flanks converging towards the ventral region, which is rounded to tabulate with a keel, but without ventral sulci, at least on the outer whorls. The innermost whorls appear to be smooth, but later ribs emerge, barely sinuous, proverse or subradial, irregular in relief, and prominent, especially towards the outer region of the flank. Ribs are usually grouped two by two near the umbilical edge, or can be simple whereas a few others may bifurcate into the lower third of the flank and all project forward in the ventral region. Some specimens present occasional thickenings near the umbilical edge coinciding with grouping of the ribs, but without a tuberculate stage. The septal suture is relatively simple, with L being wide and short. REMARKS

W. connata is distinguished from most of the congeneric species for having more prominent ribs grouped in pairs next to the umbilical edge. The most similar species is Witchellia zugophora Buckman, 1923 (Buckman 1923: T.A. 4, pl. 341) which has comparable coiling and ribbing, but is much larger and has prominent sulci bordering the keel. Other Witchellia strongly ribbed are: W. glauca Buckman, 1926 (Buckman 1926: T.A. 6, pl. 688); W. falcata Buckman, 1925 (Buckman 1925: T.A. 6, pl. 594) and W. actinophora Buckman, 1926 (Buckman 1926: T.A. 6, pl. 689). The three forms, possibly synonymous with each other, are more involute and have markedly sigmoid ribbing.

DISTRIBUTION

The HT of W. connata comes from Sherborne ( England) and was referred, with doubts, to the “Hemera Fissilobata” by Buckman (1927). In southern England, W. connata constitutes a typical horizon in the Trigonalis Subzone of the Laeviuscula Zone, but it is cited also from the Ovale and Laeviuscula zones ( Chandler & Dietze 2004; Dietze et al. 2007). In Germany, this species is recorded in the Laeviuscula Zone, Trigonalis Subzone ( Dietze et al. 2003, 2005, 2010a, 2019). In the Iberian range ( Spain), this species occurs in the Ovale and lower part of the Laeviuscula zones (Fernández-López 1985). In the Atlas Mountains ( Morocco) , it has been cited in the upper part of the Laeviuscula Zone ( Sadki 1996). Subbetic specimens are from the Laeviuscula Zone (Trigonalis Subzone) of Sierra de Alta Coloma area (sections JAC3, JAC11 and JAC22) and from a condensate bed of La Morenica (section JVM), with ammonites of the Laeviuscula Zone and the base of the Propinquans Zone, Valdepeñas de Jaén, both in Jaén Province.

Figures

FIG. 10. — A, Witchellia cf. W. nodatipinguis (Buckman, 1923) [M], JAC11.3.3, Ovale Zone,Sierra de Alta Coloma (JAC11 section);B-E, Witchellia connata (Buckman, 1927) [M]: B, C, JAC3.33.1, JAC3.33.2, Laeviuscula Zone, Trigonalis Subzone, Sierra de Alta Coloma (JAC3 section); D, E, JAC11.5.32, JAC11.R.19, Laeviuscula Zone, Trigonalis Subzone, Sierra de Alta Coloma (JAC11 section); F-K, Witchellia romanoides (Douvillé, 1885) [M]: F, J, JAC22.5.22, JAC22.5.8, Ovale Zone,Sierra de Alta Coloma (JAC22 section);G, JAC3.21.2, Laeviuscula Zone,Trigonalis Subzone, Sierra de Alta Coloma (JAC3 section);H, JFB.R.1, Laeviuscula Zone,Río Fardes area (JFB section);I, K, JAC11.R.20, JAC11.4.14,Laeviuscula Zone,Trigonalis Subzone,Sierra de Alta Coloma (JAC11 section).Scale bar:1 cm.