Liroceras Teichert, 1940

Korn, Dieter & Ghaderi, Abbas, 2025, Late Permian nautiloids from Julfa (NW Iran), European Journal of Taxonomy 1018, pp. 1-113 : 82-84

Genus Liroceras Teichert, 1940

Type species

Coloceras liratum Girty, 1911 ; original designation.

Diagnosis

Genus of the family Liroceratidae with pachyconic to globular, involute or subinvolute conch; umbilicus closed by a plug in some species. The first whorl is 10–20 mm in diameter with a very small umbilical foramen; the conch is rapidly increasing in height with a high coiling rate (WER usually higher than 2.50). Whorls weakly embracing, their profile ranges from reniform to nearly circular. Juvenile conch with longitudinal ridges or lines; adult ornament with growth lines with a fairly deep ventral sinus and spiral lines in some species. Septa without inflexions, slightly concave. Suture line simple, nearly straight with a shallow, broadly rounded internal lobe. The siphuncle has a position between the centre of the septum and the venter (after Gordon 1965; Shimansky 1967).

Included Carboniferous species

North America ( Shumard & Swallow 1858; Miller & Gurley 1897; Girty 1911; Miller et al. 1933; Newell 1936; Unklesbay 1962; Gordon 1965): Nautilus Missouriensis Swallow, 1858 , Bashkirian, Missouri; Solenochilus henryvillense Miller & Gurley, 1897 , Viséan, Indiana; Coloceras liratum Girty, 1911 , Moscovian, Oklahoma; Coloceras liratum var. obsoletum Girty, 1911 , Moscovian, Oklahoma; Coloceras greenei Miller, Dunbar & Condra, 1933 , Kasimovian, Oklahoma; Coloceras milleri Newell, 1936 , Kasimovian, Kansas; Coloceras reticulatum Miller & Owen, 1937 , Kasimovian, Oklahoma; Liroceras patulum Unklesbay, 1962 , Bashkirian, Arkansas; Liroceras bicostatum Gordon, 1965 , Serpukhovian, Arkansas.

British Isles ( Foord 1891; Hind 1910; Turner 1954; Ramsbottom & Moore 1961): Coelonautilus Derbiensis Foord, 1891 , Viséan, Derbyshire; Coelonautilus Derbiensis var. globulare Foord, 1891 , Viséan, Isle of Man; Solenocheilus globosus Hind, 1910 , Bashkirian, Lancashire; Liroceras lunense Turner, 1954 , Serpukhovian, Yorkshire; Liroceras leitrimense Ramsbottom & Moore, 1961 , Viséan, Ireland.

Central Europe ( Trenkner 1868; Hyatt 1894; Miller et al. 1933; Schmidt 1951): Nautilus grundensis Trenkner, 1868 , Viséan, Harz Mountains; Coloceras globatum Hyatt, 1894 , Viséan, Belgium; Coloceras hyatti Miller, Dunbar & Condra, 1933 , Viséan, Belgium; Liroceras occlusor Schmidt, 1951 , Viséan, Harz Mountains; Liroceras schaelkense Schmidt, 1951 , Viséan, Rhenish Mountains.

North Africa ( Korn & Klug 2023): Liroceras karaouii Korn & Klug, 2023 , Viséan, Anti-Atlas; Liroceras vermis Korn & Klug, 2023 , Serpukhovian, Anti-Atlas.

Western Russia ( Eichwald 1857; Shimansky 1967): Nautilus excentricus Eichwald, 1857 , Serpukhovian, Western Russia; Liroceras fornicatum Shimansky, 1967 , Serpukhovian, Western Russia; Liroceras devjatovense Shimansky, 1967 , Moscovian, Moscow Basin.

Urals ( Shimansky 1967): Liroceras praelunense Shimansky, 1967 , Viséan, North Urals; Liroceras ruzhencevi Shimansky, 1967 , Serpukhovian, South Urals.

North China ( Ruan & Zhou 1987): Liroceras reniforme Ruan & Zhou, 1987 , Bashkirian, Ningxia.

Included Permian species

North America ( Hyatt 1893): Coloceras globulare Hyatt, 1893 , Artinskian, Texas.

Central and Southern Europe ( Gemmellaro 1889; Prinoth & Posenato 2007): Endolobus salomonensis Gemmellaro, 1889 , Wordian, Sicily; Liroceras gardenense Prinoth & Posenato, 2007 , Changhsingian, Dolomites.

Western Russia, Urals ( Yakovlev 1899; Kruglov 1928; Barskov et al. 2014; Leonova & Shchedukhin 2020): Asymptoceras korulkense Yakovlev, 1899 , Sakmarian, South Urals; Coloceras (?) sarvaensis Kruglov, 1928 , Sakmarian (?), South Urals; Coloceras abichi var. tastubense Kruglov, 1928 , Sakmarian (?), South Urals; Liroceras volgense Barskov & Shilovsky, 2014 , Roadian, Western Russia; Liroceras shakhtauense Leonova & Shchedukhin, 2020 , Asselian or Sakmarian, South Urals.

NW Iran (this paper): Liroceras choopani sp. nov., Wuchiapingian.

Central Iran (Korn & Hairapetian in press): new species P to be described by Korn & Hairapetian (in press), Wuchiapingian.

Pakistan ( Reed 1944): Liroceras bakhense Reed, 1944 , Wuchiapingian, Salt Range.

South China ( Chao 1940, 1954; Xu 1977; Zhao et al. 1978; Liang 1984; Wu & Kuang 1992): Coloceras sinense Chao, 1940 , Kungurian, Hunan; Peripetoceras hsueyuechiani Chao, 1954 , Kungurian, Hunan; Liroceras orientale Chao, 1954 , Kungurian, Hunan; Ephippioceras hunanense Chao, 1954 , Kungurian, Hunan; Liroceras didmyoaurise Xu, 1977 , Kungurian, Hunan; Liroceras meishanense Zhao, Liang & Zheng, 1978 , Changhsingian, Zhejiang; Liroceras chenxianense Liang, 1984 , Changhsingian, Hunan; Liroceras lichuanense Wu & Kuang, 1992, Changhsingian, Hubei.

Indopacific ( Haniel 1915): Nautilus Molengraaffi Haniel, 1915 , Wuchiapingian, Timor.

Madagascar ( Vaillant-Couturier Treat 1933): Nautilus waterloti Vaillant-Couturier Treat, 1933 , Wuchiapingian.

Remarks

The genus Liroceras was introduced by Teichert (1940) for those Carboniferous and Permian nautiloids that were previously mostly included in the genus Coloceras Hyatt, 1893 . The name Coloceras had already been used by Taschenberg (1882) as a subgenus for recent Mallophaga.

Liroceras has a stratigraphic range from the Viséan to the Changhsingian and is represented by species at almost all stages of this long interval. At the same time, Liroceras is geographically widespread, both in the Carboniferous and in the Permian. Liroceras is also known from different facies areas; Early Carboniferous species are known from shallower and deeper areas of the shelf. In the Late Permian, the genus was more common in the shallower areas of the sea, as suggested by the occurrences at Julfa, where it co-occurs with the morphologically similar and closely related genus Permonautilus .