Sonniniidae Ammonitina, Middle Jurassic from Southern Spain: taxonomic, biostratigraphical and palaeobiogeographical analysis Author Sandoval, José text Geodiversitas 2022 2022-09-15 44 27 801 851 journal article 158824 10.5252/geodiversitas2022v44a27 835cc227-e5c4-4453-a956-07a154f8fa5f 1638-9395 7150329 urn:lsid:zoobank.org:pub:E4896081-9312-4EA6-AE33-AAC44201748E 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).