Vestinautilus Ryckholt 1852

Genus Vestinautilus Ryckholt, 1852 Type species Nautilus Koninckii d’Orbigny, 1850; subsequent designation by Hyatt (1883 –1884). Diagnosis Genus of the family Trigonoceratidae with evolute conch; whorls slightly impressed; whorl profile rounded-triangular or trapezoidal with flattened or weakly concave venter and pronounced ventrolateral shoulder. Ornament with fine lines and very coarse spiral ridges around the ventrolateral shoulder, sometimes also on the venter. Suture line slightly sinuous. Siphuncle small with subcentral position (after Kummel 1964; emended by Korn et al. 2022). Included species Nautilus (Trematodiscus) altidorsalis Winchell, 1862, Michigan; Nautilus biangulatus Sowerby, 1825, Southwest England; Nautilus cariniferus Sowerby, 1825, Ireland; Vestinautilus concinnus Korn, Miao & Bockwinkel, 2022, Algeria; Triboloceras formosum Foord, 1900, Ireland; Nautilus Koninckii d’Orbigny, 1850, Belgium; Nautilus multicarinatus Sowerby, 1825, Ireland; Vestinautilus padus Korn, Miao & Bockwinkel, 2022, Algeria; Coelonautilus paucicarinatus Foord, 1891, Ireland; Nautilus pinguis de Koninck, 1844, Belgium; Vestinautilus semiglaber Foord, 1900, Ireland; Vestinautilus semiplicatus Foord, 1900, Ireland; Vestinautilus angulatus sp. nov., Algeria; Vestinautilus papilio sp. nov., Algeria; Vestinautilus inflexus sp. nov., Algeria; Vestinautilus bicristatus sp. nov., Algeria. Remarks In the description of the nautiloids from the Dalle à Merocanites, Korn et al. (2022) discussed the relationships between the genera Vestinautilus and Subvestinautilus; they considered the latter as a junior synonym. Vestinautilus differs from the other genera of the family Trigonoceratidae by the rather weakly ornamented shell in combination with a rounded-triangular or trapezoidal whorl profile. However, it should be noted that some of these genera, such as Rineceras, Vestinautilus and Stroboceras, show quite similar conch and ornamentat morphology at the beginning of their occurrence in the Tournaisian.Published as part of Korn, Dieter & Bockwinkel, Jürgen, 2022, Early Carboniferous nautiloids from the Central Sahara, southern Algeria, pp. 67-108 in European Journal of Taxonomy 831 on pages 85-86, DOI: 10.5852/ejt.2022.831.1871, http://zenodo.org/record/688519