Dorsetensia hannoverana
Creators: name: Sandoval, José
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Cephalopoda
Ammonoidea
Sonniniidae
Dorsetensia
Dorsetensia hannoverana

description: Dorsetensia hannoverana (Hiltermann, 1939) [M] & [m] (Fig. 14Y, Z)
Sonninia pinguis hannoverana Hiltermann, 1939:167, text-figs 42- 45, pl. 11, figs 8 (LT), 9. — Wendt 2017: fig. 6C.
Sonninia pinguis westfalica Hiltermann, 1939: 168, pl. 11, fig. 10, text-figs 46-49.
Sonninia (Poecilomorphus) pinguis hannoverana – Huf 1968: 64, pl. 6, figs 5 (LT refigured) to fig. 12, pl. 7, figs 1-3, pl. 10, fig. 1.
Sonninia (Poecilomorphus) pinguis westfalica – Huf 1968: 69, pl. 7, figs 4, 5.
Dorsetensia hannoverana – Morton 1972: 513, pl. 105, figs 15, 16, 23, 24. — Pavia 1983: pl. 6, figs 9, 10. — Fernández-López 1985: 121, pl. 10, fig. 9. — Schlegelmilch 1985: 64, pl. 19, fig. 9 (LT refigured).
Nannina hannoverana – Fernández-López & Mouterde 1994: p. 131, pl. 3, fig. 4.
Dorsetensia pinguis hannoverana – Ohmert et al. 1995: 54, pl. 1, figs 4, 5.
? Nannina sp. [corresponds to Dorsetensia hannoverana auct.] – Dietze et al. 2008: 148, fig. 4C.
MATERIAL EXAMINED — JAC3’.22.3, JAC3’.22.25, JAC3’.22.32 and JAQ 1.67.3.
MEASUREMENTS. — See Table 30.
DESCRIPTION
The LT is small, evolute with a whorl section almost as wide as high (subquadrangular), broad ventral area with keel limited by small sulci. The ribs are mostly bifurcated from a small thickening on the umbilical edge. The Subbetic specimens, possibly macroconchs, are small sized, relatively evolute, although crushed (flattened and deformed by lateral pressure). The whorl section appears to be subrectangular with almost a vertical umbilical wall and rounded umbilical edge. The flanks are slightly convex and the ventral area is wide with a very high keel. None of the specimens analysed here preserve the peristome. The ribs, relatively strong on inner and intermediate whorls, are simple or grouped in pairs from a small thickening near the umbilical edge, and radial or only barely flexuous. Towards the outer whorls, the ribbing weakens, the simple ribs become more abundant and the ribs reach maximum relief near the middle of the flanks. The septal suture is not well preserved in the Subbetic specimens.
REMARKS
Morton (1972: 517) suggested that D. hannoverana represents macroconch forms. Later, Pavia (1983, pl. 6, figs 9, 10a) figured two macroconch forms that he attributed to this species. Fernández-López (1985: 121) showed that the specimens from the Iberian Cordillera are microconchiate forms. Subbetic specimens do not preserve the peristome, but their size, ribbing, and coiling are more similar to those of the microconchs than to the macroconchs.
DISTRIBUTION
The LT of D. hannoverana is from Hildesheim (Germany) and was placed in the “Pinguis Zone” by Huf (1968: 69). Representatives of this species from the uppermost part of Sauzei Zone have been reported in Skye, Scotland (Morton, 1976) and in the Iberian Cordillera (Fernández-López 1985). However, Pavia (1983) mentioned the species at the top of the Sauzei Zone and at the base of the Humphriesianum Zone (Subzone Romani) of Chaudon, near Digne (SE France). In Tendron (Cher, central France), the species is present in the Gervillii horizon of the Humphriesianum Zone (Fernández-López & Mouterde 1994). The Subbetic specimens are from the Propinquans Zone (Hebridica Subzone) of Sierra de Alta Coloma area (section JAC3’) and Barranco de Agua Larga (section JAQ1), both from Jaén Province.
description: Published as part of Sandoval, José, 2022, Sonniniidae Ammonitina, Middle Jurassic from Southern Spain: taxonomic, biostratigraphical and palaeobiogeographical analysis, pp. 801-851 in Geodiversitas 44 (27) on pages 844-845, DOI: 10.5252/geodiversitas2022v44a27, http://zenodo.org/record/7150329