The nautiloids from the Early Carboniferous Dalle à Merocanites of Timimoun, western Algeria Author Korn, Dieter 286CA4F3-7EBC-4AEF-A66A-B2508D001367 Museum für Naturkunde, Leibniz Institut for Research on Evolution and Biodiversity, Invalidenstrasse 43, 10115 Berlin, Germany. State Key Laboratory of Biogeology & Environmental Geology, School of Earth Sciences, China University of Geosciences, 388 Lumo Road, Wuhan, China. Dechant-Fein-Strasse 22, 51375 Leverkusen, Germany. dieter.korn@mfn.berlin Author Miao, Luyi 2171F5FC-45B5-452B-A134-CD1308B3A085 miaoluyi@cug.edu.cn Author Bockwinkel, Jürgen F7FE7EEA-B678-4FEE-879C-8C429F66BF3A jbockwinkel@t-online.de text European Journal of Taxonomy 2022 2022-01-28 789 104 129 http://dx.doi.org/10.5852/ejt.2022.789.1635 journal article 20812 10.5852/ejt.2022.789.1635 338a1525-2dbe-4c49-99b9-737a0b17334d 2118-9773 5965355 A475F919-D925-457E-B007-3FE2B55659A3 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). Included species Nautilus ( Trematodiscus ) altidorsalis Winchell, 1862 , Michigan; Nautilus biangulatus Sowerby, 1825 , Southwest England ; Nautilus cariniferus Sowerby, 1825 , Ireland ; Vestinautilus concinnus sp. nov. Algeria ; Triboloceras formosum Foord, 1900 , Ireland ; Nautilus Koninckii d’Orbigny, 1850 , Belgium ; Nautilus multicarinatus Sowerby, 1825 , Ireland ; Vestinautilus padus sp. nov. , Algeria ; Coelonautilus paucicarinatus Foord, 1891 , Ireland ; Nautilus pinguis de Koninck, 1844 , Belgium ; Vestinautilus semiglaber Foord, 1900 , Ireland ; Vestinautilus semiplicatus Foord, 1900 , Ireland . Remarks When Turner (1954) revised the genus Vestinautilus , he explicitly restricted the genus “to forms resembling the type species in possessing a venter concave or channelled at some stage of growth, a broad, depressed whorl profile, and a conch ornamented with spiral ribs, lirae and sulci.” At the same time, he introduced the new genus Subvestinautilus , which he placed in the family Temnocheilidae Mojsisovics, 1902 . He stated that “the genus much resembles Vestinautilus … in shape but lacks a concave or channelled venter at any stage of development.” However, since he regarded Vestinautilus as belonging to the family Triboloceratidae Hyatt, 1884 , he indirectly regarded the close morphological similarity as a result of convergent evolution. This opinion was followed (albeit with other family names) by Shimansky (1967) and Histon (1999) , but rejected by Dzik (1984) , who treated Subvestinautilus as a synonym of Vestinautilus . Here, we accept the separation of the two genera, but not the restrictive practice of Turner (1954) , who considered the ventral shape (concave or convex) as the distinguishing character. The rather variable shape of the venter, which often changes throughout ontogeny in some of the species, can hardly be regarded as a criterion for distinguishing between the two families. We therefore assign those species with coarse spiral ridges and a broad trapezoidal whorl profile, whether they possess a concave or convex venter, to Vestinautilus . Stratigraphic range Late Tournaisian to Viséan.