Solenochilus Meek & Worthen, 1870

Korn, Dieter & Klug, Christian, 2023, Early Carboniferous coiled nautiloids from the Anti-Atlas (Morocco), European Journal of Taxonomy 885, pp. 156-194 : 184

Genus Solenochilus Meek & Worthen, 1870

Type species

Nautilus (Cryptoceras) Springeri White & St. John, 1868 ; original designation.

Diagnosis

Genus of the family Solenochilidae with pachyconic to globular, involute or subinvolute conch. The conch is very rapidly increasing in height with an extremely high coiling rate (WER usually higher than 4.00). Adult body chamber with long lateral outgrowths. Whorls weakly without contact or embracing, their profile ranges from reniform to nearly circular. Suture line simple, nearly straight with a small annular lobe. The siphuncle has a position adjacent to the venter (after Gordon 1965; Shimansky 1967).

Included Early Carboniferous species

Gordon (1965: 152) gave an overview of the previously described species of Solenochilus . He listed 24 species (some with question marks), most of which are known from Late Carboniferous strata of North America.

So far, only a few Early Carboniferous species are known from two regions:

British Isles( Phillips 1836; Foord 1891, 1901): Nautilus dorsalis Phillips, 1836 ,Yorkshire; Solenocheilus Hibernicus Foord, 1891 , Ireland; Solenocheilus clausus Foord, 1901 , Ireland.

North Africa (this paper): Solenochilus lucynae sp. nov., Anti-Atlas; Solenochilus pohlei sp. nov., Anti-Atlas.

Remarks

Solenochilus is a genus whose species are mainly known from late Carboniferous strata of North America. Gordon (1965) published an identification key for these species, in which the species described from Europe can also be included. However, it is clear that this key does not represent a phylogenetic scheme and that it contains species with different ontogenetic stages.

Most occurrences of specimens of the genus are in sediments of the shallow shelf; therefore, Solenochilus is usually only rarely found together with ammonoids. For example, the genus is apparently absent from the assemblages of the Dalle à Merocanites of Timimoun (Korn et al. 2022) and Gara el Itima N; both are occurrences characterised by a high number of ammonoid specimens. The comparatively frequent occurrence of the genus in layers with many ammonoids at Rissani is therefore an exception.