Endolobus Meek & Worthen, 1865

Korn, Dieter & Klug, Christian, 2023, Early Carboniferous coiled nautiloids from the Anti-Atlas (Morocco), European Journal of Taxonomy 885, pp. 156-194 : 170-171

Genus Endolobus Meek & Worthen, 1865

Type species

Nautilus (Endolobus) peramplus Meek & Worthen, 1865 (= Nautilus spectabilis Meek & Worthen, 1860 ); original designation.

Diagnosis

Genus of the family Trigonoceratidae with usually pachyconic, subinvolute or evolute conch; whorls usually slightly impressed, whorl profile compressed with broadly rounded or slightly flattened venter and rounded umbilical margin. Conch very rapidly increasing in height with a high coiling rate (WER usually higher than 2.50). Sculpture with broad, rounded nodes on the flanks. Septa without inflexions, moderately concave. Suture line nearly straight with very shallow external lobe and usually with an internal lobe; some species with an annular lobe. Siphuncle with subcentral position.

Included Early Carboniferous species

North America( Meek & Worthen 1860, 1865; Miller & Gurley 1897; Miller & Collins 1947; Youngquist 1949; Collinson 1955; Sweet & Brookley 1956): Nautilus spectabilis Meek & Worthen, 1860 , Illinois; Nautilus (Endolobus) peramplus Meek & Worthen, 1865 (synonym of Nautilus spectabilis ); Temnochilus greenense Miller & Gurley, 1897 , Indiana; Endolobus greenbrierensis Miller & Collins, 1947 , Pennsylvania; Solenochilus occidens Youngquist, 1949 , Nevada; Endolobus clorensis Collinson, 1955 ; Kentucky; Endolobus indianensis Sweet & Brookley, 1956 , Indiana.

North Africa (this paper): Endolobus rota sp. nov., Anti-Atlas.

Remarks

Endolobus is a genus in need of revision both in its definition and possible phylogenetic position. For example, according to Gordon (1965), the annular lobe belongs to the diagnosis of the genus, whereas Shimansky (1967) did not consider this a necessary character. The assignment of the material from the Anti-Atlas can therefore only be tentative. Early Carboniferous species are known mainly from North America (for a species list, see Gordon 1965). Most of them are very large specimens, which makes a comparison with considerably smaller specimens difficult. The material from the Anti-Atlas is not very typical for Endolobus and occupies a marginal position within the genus.