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

description: Witchellia macer (Buckman, 1889) [m] (Fig. 14 F-I)
Poecilomorphus macer S. Buckman, 1889: 116, pl. 22, only figs 23- 28. (HT).
Maceratites aurifer Buckman, 1928: T.A. 7, p. 11, pl. 766, figs 1-3. — Fernández-López 1985: 95, pl. 11, figs 11, 12, 14. — Ohmert 2004: 62, pl. 16, figs 1, 2. — Metodiev 2019: 17, fig. 6.
Maceratites costulatus Buckman, 1928: T.A. 7, p. 11.
Pelekodites macer – Morton 1975: 65, pl.10, figs 5, 6, 11, 12, 17- 22, 25-30. — Ohmert 2004: 64, pl. 16, figs 3, 4. — Dietze et al. 2019: 58, figs 4(3), 8(2a-10b).
non Maceratites macer – Fernández-López 1985: 97, text-fig. 9, pl. 11, figs 17, 18.
Maceratites costulatus – Fernández-López 1985: 98, pl. 11, fig. 13.
Pelekodites cf. aurifer – Dietze et al. 2007: 16, figs 4h-k.
Pelekodites cf. macer – Dietze et al. 2019: 58, figs 8(11a, b).
? Pelekodites boweri – Dietze et al. 2019: 60, figs 8(1a, b).
MATERIAL EXAMINED. — JST.93.6, FAa.4.1, JAC3. R.1, JAC3’.2.5, JAC4.39.58, JAC11.4.3, JAC11.5.8, JAC11.5.16, JAC22.39.3, JAC22.42.9, JAC22.42.10, JAC22.42.11, JAC22.42.12, JAC22.42.13, JAC22.43.20, JAC22.43.21, JAC22.43.22, JAC22.43.23, JAC22.43.24, JAC22.43.25, JAC22.44.9, JAC22.45.12, JAC22.45.13, JAC22. 49.1, JAC22. R.7. JVM.36, JVM.37, JVM.38, JVM.41, JVM.42 and JVM.43.
MEASUREMENTS. — See Table 22.
DESCRIPTION
Small and evolute shells (O/D varying from 0.35 to 0.40) with ovate-subrectangular compressed whorl section, convex umbilical wall, rounded umbilical edge, slightly convex flanks, venter with fine and well-marked keel, but not high and at times bordered by small sulci. The aperture is complex with lateral lappets and a small ventral rostrum. The inner whorls are smooth or almost smooth, without apparent ribs or tubercles, and later develop sigmoid ribs, well-differentiated at least up to the first half of the adult BC. These ribs, usually simple and sometimes grouped in pairs just at the umbilical border, are decidedly proverse in the inner third of the flanks, where they are weak; then they become prominent and sharp extending to the outer region, strongly projecting forward as they again become thinner and weaker. The septal suture is not visible in the Subbetic specimens.
REMARKS
The types of “ Maceratites ” macer and “ M. ” aurifer are strikingly similar and have equivalent stratigraphic positions in the type localities. The only observable differences are less strongly falcate and slightly stronger ribbing in “ M. ” aurifer and the presence of small grooves (sulci) limiting the keel in “ M. ” macer, which are absent in “ M. ” aurifer. The two Buckman species are considered synonymous here, with “ M. ” macer having nomenclatorial priority. Also, “ Maceratites ” costulatus (Buckman, 1928: 11; HT, Poecilomorphus macer Buckman in S. Buckman 1889, pl. 22, only figs 25, 26) may be synonymous with “ M. ” macer. This morphotype was originally distinguished from “ M.” macer by having more regular, prominent, and dense ribbing in the adult stage. It shows intermediate characters between typical “ M.” macer and the primitive Witchellia moisyi (Brasil, 1893).
DISTRIBUTION
The LT of “ Witchellia macer comes from the marl with green grains of Frogden Quarry, Dorset, England (Buckman 1928: 12), Lower Bajocian (Laeviuscula Zone and Subzone). The species has also been cited from the Laeviuscula Zone in England (Parsons 1974, 1979) and Scotland (Morton 1975). According to Dietze et al. (2009, 2010a, 2011 b, 2019), W. macer marks a typical horizon in the Trigonalis Subzone of the Upper Rhine Valley (SW Germany). In the Iberian Range (Spain), it is abundant in the upper part of the Ovale Zone and in the lower part of the Laeviuscula Zone (Fernández-López 1985: 97, fig. 113), but the specimens figured there diverge markedly from of the LT, with ornamentation reduced to striae, and it is not clear that they belong to this species. The HT of “ Maceratites aurifer ” (Buckman, 1928) comes from Bj-10a (Laeviuscula Zone and Subzone) from Dundry (Dorset, England) (Chandler et al. 2006: 348, fig. 2). In the Iberian range, the specimens classified as “ Maceratites aurifer ” are from the Ovale, Laeviuscula, and the base of the Propinquans zones (Fernández-López 1985: fig. 13). The Subbetic specimens are from the Laeviuscula Zone of JVM section (Cerro de la Martinica), Valdepeñas de Jaén, JST (Sierra del Trigo), JAC3, JAC3’, JAC4, JAC11 and JAC22 (Sierra de Alta Coloma area) sections (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 836-837, DOI: 10.5252/geodiversitas2022v44a27, http://zenodo.org/record/7150329