Fididomatoceras, Korn & Ghaderi, 2025

Korn, Dieter & Ghaderi, Abbas, 2025, Late Permian nautiloids from Julfa (NW Iran), European Journal of Taxonomy 1018, pp. 1-113 : 21-22

Genus Fididomatoceras gen. nov.

urn:lsid:zoobank.org:act:

New genus A – Korn 2025: 39.

Type species

Fididomatoceras intracostatum gen. et sp. nov.

Diagnosis

Genus of the family Domatoceratidae with a small to moderately large, subinvolute conch; whorl profile lyriform, venter flat or concave and bordered by raised keels, umbilical margin narrowly rounded. Sculpture missing or with blunt ribs on the flanks in the juvenile stage. Suture line with narrow, rounded external lobe and broadly rounded lateral lobe.

Etymology

Combination of the Latin ‘ fidis ’ (noun, f.) =‘lyre’ and Domatoceras ; because of the lyriform whorl profile.

Included species

Transcaucasia ( Shimansky 1965b; this paper): Fididomatoceras gracile (Shimansky, 1965) gen. et comb. nov., Wuchiapingian, Azerbaijan; Fididomatoceras intracostatum gen. et sp. nov., Wuchiapingian, NW Iran.

Remarks

The new genus differs from most other genera in the family Domatoceratidae by its narrow umbilicus (uw/dm=0.25–0.30), which in the other genera is usually much wider (uw/dm = 0.35–0.40). The most important distinguishing feature, however, is the shape of the ventrolateral shoulder, which in the other genera is tightly rounded or simply subangular or angular, but in Fididomatoceras gen. nov. is accentuated by a shallow inflexion of the outer flank. The lyriform whorl profile in Fididomatoceras is also the main difference to the otherwise similar Late Carboniferous genus Stenodomatoceras .