Temnocheilus M‘Coy, 1844

Korn, Dieter & Klug, Christian, 2023, Early Carboniferous coiled nautiloids from the Anti-Atlas (Morocco), European Journal of Taxonomy 885, pp. 156-194 : 163

Genus Temnocheilus M‘Coy, 1844

Type species

Nautilus (Temnocheilus) coronatus M‘Coy, 1844 ; subsequent designation by Hyatt (1883 –1884).

Diagnosis

Genus of the family Trigonoceratidae with discoidal to pachyconic, usually subevolute conch. The first whorl is about 30 mm in diameter with an umbilical foramen about 12 mm wide; the conch is rapidly increasing in height with a high coiling rate (WER usually higher than 2.00). Whorls weakly embracing, their profile triangular with more or less angular umbilical margin. Sculpture with longitudinal tubercles along the ventral margin. Septa usually without inflexions, rather deeply concave. Suture line with shallow ventral and deeper lateral, rounded internal lobe. The siphuncle has a position between the centre of the aperture and the venter (after Shimansky 1967).

Included Early Carboniferous species

Most of the species of Temnocheilus are known from Late Carboniferous and Permian strata ( Shimansky 1967: 98). Early Carboniferous species are known from three regions:

British Isles ( Sowerby 1821; M‘Coy 1844; Hind 1914; Platt 1938): Nautilus tuberculatus Sowerby, 1821 , Scotland; Nautilus (Temnocheilus) coronatus M‘Coy, 1844 , Ireland; Temnocheilus derbiensis Hind, 1914 , England; Temnocheilus ventro-concavus Platt, 1938 , Scotland.

South Urals ( Shimansky 1967): Temnocheilus coronatiformae Shimansky, 1967 ; South Urals.

North Africa (this paper): Temnocheilus imazighenorum sp. nov., Anti-Atlas; Temnocheilus aubrechtovae sp. nov., Anti-Atlas.

Remarks

For a discussion of the composition and limits of the genus, see Korn & Bockwinkel (2022).