Cadomites (Cadomites)

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

Cadomites (Cadomites) sp.

( Figs 4B ; 5T, U )

REMARKS

Very small nuclei of which one is figured here.

Cadomites Munier-Chalmas, 1892 was also documented from the Kambe limestone by Westermann (1975) with a beautiful specimen ( Westermann 1975: pl. 2, fig.8), and probably with his ‘? Torrensia sp. nov. ’ ( Westermann 1975: pl. 2, fig. 10). The latter is a nucleus, a fragment that is difficult to determine correctly, however shows a suture-line ( Westermann 1975: text-fig. 6A) which is close to that observed on small Cadomites , including the one figured here ( Fig. 4B ). Ventral weakening of the ribbing and constrictions are uncommon but do occur on the inner whorls of Cadomites .

Masckeites cf. psilacanthoides ( Sandoval, 1983) ( Fig. 6C )

cf. Cadomites (Polyplectites) psilacanthoides Sandoval, 1983: 295 , pl. 21, figs 3, 5, 7, text-fig. 109.

cf. Polyplectites psilacanthoides – Sandoval 1990: 158, pl. 3, fig. 7.

cf. Masckeites psilacanthoides – Galácz 1994: 168, pl. 3, fig. 2.

REMARKS

A small (33 mm) specimen, showing only the lateral and ventral side of the last whorl.The identification was based on the sculpture that is typically stephanoceratid with short inner ribs ending in rounded tubercles where the radial secondary ribs arise in threes and fours. Closest form is Masckeites psilacanthoides , described originally from the Niortense Zone ( Sandoval 1983: 295). Masckeites Buckman, 1920 was suggested as the microconch pair for macroconchiate Lokuticeras Galácz, 1994 (see Galácz 1994). Remarkable is that a Lokuticeras - type stephanoceratid, the similarly Niortense Zone ‘ Cadomites aff. C. lissajousi’ Roché, 1939 was figured from a nearby locality by Westermann (1975: pl.2,fig.8).

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.

FIG. 6. — A, B, Lytoceras eudesianum eudesianum (d’Orbigny, 1846) MR 1, EMNH.2015.184; C, Masckeites cf. psilacanthoides (Sandoval, 1983) MR 2, EMNH.2015.278; D, Leptosphinctes cf. schmiereri (Bentz, 1924) MR 2, EMNH.2015.224. Scale bar: 10 mm.