Ephippioceras Hyatt, 1884

Korn, Dieter & Klug, Christian, 2023, Early Carboniferous coiled nautiloids from the Anti-Atlas (Morocco), European Journal of Taxonomy 885, pp. 156-194 : 181-182

Genus Ephippioceras Hyatt, 1884

Type species

Nautilus ferratus Cox, 1858 ; original designation.

Diagnosis

Genus of the family Ephippioceratidae with pachyconic to globular, involute conch. The first whorl is about 10 mm in diameter; the conch is rapidly increasing in height with a high coiling rate (WER usually higher than 2.50). Whorls weakly embracing, with reniform profile. Shell surface smooth, sometimes with fine spiral lines. Septa bipartite by a median inflexion and two strongly concave lateral sides. Suture line with subtriangular external saddle, shallow lobes on flanks and umbilical wall and rounded internal saddle. The siphuncle has a position between the centre of the aperture and the venter (after Gordon 1965; Shimansky 1967).

Included Early Carboniferous species

North America ( Cox 1858): Nautilus ferratus Cox, 1858 , Kentucky.

British Isles ( Sowerby 1821; Ramsbottom & Moore 1961): Nautilus bilobatus Sowerby, 1821 , Scotland; Ephippioceras spirale Ramsbottom & Moore, 1961 , Ireland.

North Africa (this paper): Ephippioceras pygops sp. nov.; Anti-Atlas.

West Russia and Urals ( Hyatt 1891; Fredericks 1915; Shimansky 1967): Ephippioceras Verneuili Hyatt, 1891 , South Urals; Ephippioceras mosquense Fredericks, 1915 , Moscow Basin; Ephippioceras sphaericum Shimansky, 1967 , South Urals.

Remarks

Ephippioceras is a genus of which several of the species are known from only a few specimens; furthermore, the very different sizes of the described specimens make a comparison difficult. Another problem is the often fragmentary preservation of the material.