Diplesioceras sp.

Galácz, András, 2017, Bajocian (Middle Jurassic) ammonites of stratigraphical and palaeobiogeographical importance from Mombasa, Kenya, East Africa, Geodiversitas 39 (4), pp. 717-727 : 723

? Diplesioceras sp.

( Figs 4C ; 5S )

REMARKS

This is a half-whorl phragmocone fragment of an ammonite with flattish flanks, relatively wide venter with low, blunt keel on it and weak, rounded, biplicate ribs.

The only similar specimen is the Diplesioceras sp. nov. 1 in Fernández-López (1985:204,pl.17,fig.8),a small specimen from the Garantiana Zone of the Iberian Cordilleras.The Mombasa am - monite has comparable size proportions and shows the same style of ribbing. Its suture-line is very similar to that of the Diplesioceras diplesium Buckman, 1920 figured by Dietl (1974: text-fig. 7).

Diplesioceras is a strange genus regarded incertae sedis by Donovan et al. (1981: 118) and grouped together with the haploceratid Poecilomorphus by Fernández-López (1985: 204). Recently Howarth (2013: 121) ranged the genus into the Hildoceratoidea, as incertae sedis.

Figures

FIG. 4. — Suture lines of some important species: A, Oecotraustes sp. MR 1, EMNH.2015.249; B, Cadomites (Cadomites) sp. MR 1, EMNH.2015.232; C,?Diplesioceras sp. MR 1, EMNH.2015.180; D, Spiroceras annulatum (Deshayes, 1831) MR 2, EMNH.2015.287; E, Leptosphinctes cf. schmiereri (Bentz, 1924) MR 2, EMNH.2015.224; F, Nannolytoceras polyhelictum (BÖckh, 1881) MR 2, EMNH.2015.257; G, Trimarginia sp. MR 2, EMNH.2015.279. Scale bar: 5 mm.

FIG. 5. — A, B, Phylloceras trifoliatum Neumayr, 1871 MR 1, EMNH.2015.286; C, D, Phylloceras trifoliatum Neumayr, 1871 MR 2, EMNH.2015.285; E, F, Ptychophylloceras lardyi (Ooster,1860) MR 1, EMNH.2015.303; G, H, Calliphylloceras disputabile (Zittel,1868) MR 1, EMNH.2015.304; I, J, Holcophylloceras zignodianum (d’Orbigny, 1848) MR 1, EMNH.2015.259; K, L, Nannolytoceras polyhelictum (BÖckh,1881) MR 2, EMNH.2015.257;M, N, Trimarginia sp. MR 2, EMNH.2015.279; O, P, Lissoceras oolithicum (d’Orbigny,1845) MR 2, EMNH.2015.268;Q, R, Oecotraustes sp. MR 1, EMNH.2015.249;S,?Diplesioceras sp.MR 1, EMNH.2015.180; T, U, Cadomites (Cadomites) sp. MR 1, EMNH.2015.232; V, W, Normannites egyptiacus Arkell, 1952 MR 2, EMNH.2015.288; X, Y, Spiroceras annulatum (Deshayes, 1831) MR 2, EMNH.2015.287. Scale bar: 10 mm.