Dorsetensia regrediens ( Haug, 1893 )

Sandoval, José, 2022, Sonniniidae Ammonitina, Middle Jurassic from Southern Spain: taxonomic, biostratigraphical and palaeobiogeographical analysis, Geodiversitas 44 (27), pp. 801-851 : 843

Dorsetensia regrediens ( Haug, 1893) [m] ( Fig. 14U )

Witchellia regrediens Haug, 1893: 318 , pl. 10, fig. 7.

Dorsetensia edouardiana – Buckman 1892: 304, pl. 52, figs 8-13, 15-17.

Dorsetensia (Nannina) regrediens – Pavia 1983: 67, pl. 6, fig. 8.

Nannina regrediens – Fernández-López 1985: 119, pl. 10, fig. 2.

Dorsetensia regrediens – Dietze et al. 2011a: 215, pl. 1, figs 19-22.

MATERIAL EXAMINED. — JRi3.28.1 .

MEASUREMENTS. — See Table 28.

DESCRIPTION

The only available specimen is small with a discoidal shell, a wide umbilicus, almost vertical umbilical wall, rounded umbilical edge, and gently convex flanks. The ventral region cannot be seen, nor the shape of the aperture, although the specimen looks almost complete. The simple and relatively dense falcoid-sigmoid ribs persist to the end of the spiral.

REMARKS

The most similar species is Dorsetensia edouardiana (d’Orbigny 1845: 392) , but it is larger and more involute and has more sigmoid ribbing. According to Dietze et al. (2011a: 217), a LT of D. regrediens has never been selected. The same authors ( Dietze et al. 2011a: 217) interpreted D. edouardiana (d’Orbigny, 1845) , D. pulchra (Buckman, 1892) , D. regrediens ( Haug, 1893) , and D. lennieri ( Brasil, 1894) as microconchiate “species”, which could be the dimorphic couple of D. tessoniana (d’Orbigny, 1845) [M]. However, several of the specimens figured as D. edouardiana by Huf (1968) and by Dietze et al. (2011a) seem rather to represent macroconchiate forms. If the idea proposed by Dietze et al. (2011a) were true, all four taxa would be synonymous.

DISTRIBUTION

The type of D. regrediens is from the “Oolithe ferrugineuse” of Saint-Vigor, near Bayeux, France ( Haug 1893; Dietze et al. 2011a). In Frogden Quarry (Dorset, England), D. regrediens occurs in the Inferior Oolite Formation, bed 4b, Lower Bajocian, the Humphriesianum Zone, Romani Subzone, Bj-14 horizon ( Callomon & Chandler 1990; Dietze et al. 2011a: 218). In Chaudon, Digne area (SE France), in the Iberian ranges ( Spain), and in the Atlas Mountains ( Morocco) , the species is present in the Romani Subzone, the lower part of the Humphriesianum Zone ( Pavia 1983; Fernández-López 1985; Sadki 1996). The only Subbetic specimen is from the Humphriesianum Zone, Romani (= Cycloides) Subzone of Sierra de Ricote (Murcia Region).

Figures

FIG. 14. — A-E, Witchellia peleka (Buckman, 1923) [m]: A, TT.76.1, Ovale? Zone, Sierra de Alta Coloma;B, JA13.34.2,Ovale Zone, Sierra de Alta Coloma (JAC13 section); C, JAQ1.(-15).1, Ovale Zone, Barranco de Agua Larga (JAQ1 section); D, JSP1, Ovale Zone, Sierra de San Pedro, Jaén province; E, MOD.R.1, Ovale Zone?, Montillana, (MOD section); F-I, Witchellia macer (Buckman, 1889) [m]; F, FAa.4.1, Laeviuscula Zone?, Sierra de Alta Coloma área; G, JVM.42, bed with ammonite of the Laeviuscula and Propinquans zones, La Martinica section; H, JST.93.6, Laeviuscula Zone, Sierra del Trigo, Jaén province; I, JAC22.49.1, Laeviuscula Subzone, Sierra de Alta Coloma (JAC22 section); J, Witchellia minima (Hiltermann, 1939) [m], JAC22.43.26, Laeviuscula Zone, Trigonalis Subzone, Sierra de Alta Coloma (JAC22 section); K-O, Witchellia moisyi (Brasil, 1893) [m]; K, JAC11.6?.7, Laeviuscula Zone?, Sierra de Alta Coloma, (JAC11 section); L, M, JAC6.R.14, JAC6.R.7, Propinquans Zone, Sierra de Alta Coloma área, (JAC6 section); N, O, JAQ1.67.2, JAQ1.67.1, Propinquans Zone, Barranco de Agua Larga (JAQ1 section);P, Q, Dorsetensia liostraca Buckman,1892 [M], JGa8.32.4,JGa8.32.2,Humphriesianum Zone,Romani Subzone,Sierra de Gaena (sections, JGa2);R, S, Dorsetensia hebridica Morton,1972 [M];R, JAC3.118.4,Propinquans Zone,Hebridica Subzone,Sierra de Alta Coloma (JAC3 section);S, JAC3’.22.44,