Dorsetensia hebridica Morton, 1972

Sandoval, José, 2022, Sonniniidae Ammonitina, Middle Jurassic from Southern Spain: taxonomic, biostratigraphical and palaeobiogeographical analysis, Geodiversitas 44 (27), pp. 801-851 : 842

Dorsetensia hebridica Morton, 1972 [M] ( Fig. 14 R-S)

Dorsetensia hebridica Morton, 1972: 516 , pl. l05, figs 13, 14, 21, 22, 25-26 (HT). — Dietze et al. 2008: fig. 6d (HT refigured).

Dorsetensia gr. hebridica – Fernández-López 1985: 63, text-fig. 6A, pl. 10, figs 5-7.

Dorsetensia cf. hebridica – Sandoval 1990: 149, pl. 2, fig. 7.

Dorsetensia sp. aff. D. hebridica – Fernández-López & Mouterde 1994: 134, pl. 3, figs 2?, 3.

? Dorsetensia aff. hebridica – Dietze et al. 2011a: 51, pl. 8, fig. 6.

MATERIAL EXAMINED. — JAC3.119.4 , JAC3’.22.4 , JAC3’.22.15 , JAC3’.22.19 and JAC3’.22.44.

MEASUREMENTS. — See Table 26.

DESCRIPTION

Moderately involute to semievolute, whorl section compressed subrectangular with a steep to vertical umbilical wall, a rounded umbilical edge, barely convex flanks, and tabulate but nonbisulcate venter with a high keel. The ribs, which arise near the umbilical edge, are mainly simple, strong, and spaced on the inner and middle whorls, but fade on the outer whorls to become almost smooth in some specimens. The ribs are scarcely flexed on the whorl sides, but ventrally strongly project forward. The specimens available are incomplete but two preserve a half whorl of the BC; all are laterally flattened. The septal suture is not well preserved in the Subbetic specimens. REMARKS

According to Morton (1972), the species most closely related to D. hebridica are D. pinguis , and D. hannoverana , but the former is larger and slightly more involute. Also all specimens of D. hebridica show a decline of the ribbing on the BC, whereas this is sporadic in D. pinguis and in no case occurs in D. hannoverana . Morton (1972: 517) proposed a dimorphic relationship between D. hannoverana [M] and D. hebridica [M] on one hand and D. pinguis [m] on the other, assuming that the macroconchs D. hannoverana and D. hebridica are less variable than the microconch, including the microconchs in D. pinguis . The assumption here is that this is correct and consequently the three species are synonymous with each other. In this case, D. pinguis would be the valid species, but the material analysed here, not very abundant and quite deformed, does not provide conclusive results and therefore, it has been deemed preferable to use the three taxonomic names.

DISTRIBUTION

According to Morton (1972: 517), the HT of D. hebridica comes from the lower part of the Humphriesianum Zone, basal bed of the Upper Sandstones, east of Torvaig, near Portree, Isle of Skye, Scotland. Later, Morton (1975, 1976) introduced a Hebridica Subzone for the upper part of the Sauzei (Propinquans) Zone. The species occurs in this stratigraphic interval in several localities of Western Europe and Morocco. The Subbetic specimens are from the uppermost part of the Propinquans Zone, Hebridica Subzone, of Sierra Alta Coloma (sections JAC3, JAC3’; Jaén Province).

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,