Sonninites Buckman, 1923

Sandoval, José, 2022, Sonniniidae Ammonitina, Middle Jurassic from Southern Spain: taxonomic, biostratigraphical and palaeobiogeographical analysis, Geodiversitas 44 (27), pp. 801-851 : 820

Genus Sonninites Buckman, 1923 [M] & [m]?

Sonninites Buckman, 1923 : pl. 428A.

Sonnites – Buckman 1925: T.A. 5, pl. 528A, nom. null. (misspelling).

TYPE SPECIES. — Sonninites felix Buckman, 1923 (Buckman 1923: T.A. 5, pl. 428A [OD]).

DESCRIPTION

Inner whorls planulate, then involute and again uncoiling in the last half whorl. In the middle and outer whorls, the whorl section is oxycone compressed with steep, sharp-edged umbilical walls, flat or slightly convex sides, and rounded to fastigiate and keeled ventral region. Subdued ribbing on the inner whorls show single or divided ribs that are hardly if ever tuberculate and become completely smooth quite early while retaining a characteristic radial striation. The suture is complex and highly indented. Specimens, which clearly represent Sonninites microconchs, have not been described, although according toChandler et al. (2006: 369), the paratype of Sonninites felix Buckman, 1923 (Buckman 1923: T.A. 5, pl. 423B) is almost certainly the microconch of this species, nevertheless this form is more probably S. (Sonninia) corrugata ( Sowerby, 1824) . In the Subbetic domain, in beds containing abundant Sonninites [M], microconchiate forms (“ Pelekodites ” sulcatus ) appear showing attenuated ribs in the middle part of the flanks on the adult BC, which is keeled and occasionally bisulcate well-developed lateral lappets; they, represent their dimorphic partner of Sonninites .

REMARKS

Sonninites macroconchs can be similar to certain involute species of Witchellia , but are smoother, have a more complex suture, and lack the subquadratic whorl section and the tabulate or bisulcate ventral area of that genus. S. ( Sonninia ) is more evolute and has more marked and persistent ribbing and tubercles. The presumable microconchiate Sonninites (“ Pelekodites ” sulcatus group) are practically indistinguishable from the microconchs of Witchellia .

DISTRIBUTION

The HT of the type species, So. felix (Buckman, 1923) comes from the Sauzei (Propinquans) Zone, Bj-11a horizon, ( Chandler et al. 2006: 369). The genus spans the Laeviuscula? – Propinquans zones: England (Buckman 1892, 1923, 1926; Chandler et al. 2006), Scotland ( Morton 1975), France ( Gillet 1937, Roché 1943, Pavia 1983, De Baets et al. 2008), Germany ( Dorn 1935, Dietze et al. 2009, 2011a, b, 2020), Morocco ( Sadki 1996), and the Iberian Cordillera and Majorca in Spain (Fernández-López 1985; Sandoval 1983, 1994). In the Subbetic domain, the subgenus is common in the Propinquans Zone of Sierra de Alta Coloma area (Jaén Province).