The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran) Author Korn, Dieter 286CA4F3-7EBC-4AEF-A66A-B2508D001367 Museum für Naturkunde, Leibniz Institut for Research on Evolution and Biodiversity, Invalidenstrasse 43, 10115 Berlin, Germany. dieter.korn@mfn.berlin Author Hairapetian, Vachik 1AB10F8F-4576-481B-9270-5DCD25110DBB Department of Geology, Esfahan (Khorasgan) Branch, Islamic Azad University, Esfahan, Iran. vhairap@gmail.com Author Ghaderi, Abbas 925F2B42-7326-4461-B2A6-83CB83ECCC63 Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Azadi Square, 9177948974, Mashhad, Iran. aghaderi@um.ac.ir Author Leda, Lucyna 81481AFA-C8EE-4E90-A954-FD0E7987621E Museum für Naturkunde, Leibniz Institut for Research on Evolution and Biodiversity, Invalidenstrasse 43, 10115 Berlin, Germany. lucyna.skorpion3@wp.pl Author Schobben, Martin 44C2A45A-B16C-434F-8F22-FC9C0FCA2551 Utrecht University, Department of Earth Sciences, Princetonlaan 8 A, 3584 CB Utrecht, The Netherlands. & Department of Geology, Esfahan (Khorasgan) Branch, Islamic Azad University, Esfahan, Iran. schobbenmartin@gmail.com Author Akbari, Amir 3C9DB6F9-2034-418F-876C-49359D07D29F Department of Geology, Esfahan (Khorasgan) Branch, Islamic Azad University, Esfahan, Iran amakbari80@yahoo.com text European Journal of Taxonomy 2021 2021-10-27 776 1 106 journal article 3782 10.5852/ejt.2021.776.1559 453c885c-f427-4a38-ab97-dc14b686e126 2118-9773 5604715 226B6C59-8620-4A29-9BEF-359BE67A1A2C Stoyanowites aspinosus Korn & Ghaderi in Korn et al. , 2016 Fig. 62 ; Table 36 Stoyanowites aspinosus Korn & Ghaderi in Korn et al. , 2016: 885 , text-fig. 43. Diagnosis Species of Stoyanowites with conch reaching 100 mm dm. Subadult stage with oval, weakly compressed whorl profile (ww/wh =0.70) and rounded venter; 15 narrow and rounded ribs on the flanks. Adult stage with oval and weakly compressed whorl profile (ww/wh = 0.60–0.70) and moderately wide to wide umbilicus (uw/dm =0.40–0.50), rounded venter and rounded ventrolateral shoulder; very weak ribs on the flanks, coarsest in ventrolateral area. Prongs of external lobe bifid; 8–9 notches of E, A and L lobes. Material examined Holotype IRAN • West Azerbaijan , Aras Valley section ; Paratirolites Limestone , 0.95 m below the top; illustrated by Korn & Ghaderi in Korn et al. (2016 : text-fig. 43a); MB.C.25458 . Additional material IRAN • 1 specimen ; Esfahan Province , Baghuk Mountain 1 section ; Hambast Formation ; MB.C.300978 • 2 specimens ; Esfahan Province , Baghuk Mountain A section ; Hambast Formation ; MB.C.30098 to MB.C.30099 • 1 specimen ; Esfahan Province , Baghuk Mountain C section ; Hambast Formation ; MB.C.30100 • 1 specimen ; Esfahan Province , Baghuk Mountain E section ; Hambast Formation ; MB.C.30101 . Description Specimen MB.C.30100 is a fragmentary specimen with 72 mm diameter and shows the wide umbilicus (uw/dm =0.50), the nearly parallel-sided whorl profile and the rounded venter. The ornament of the last half volution consists of numerous (about 25) rather sharp ribles, which extend with a shallow sinus across the flanks and turn forward in the ventrolateral area, where they become coarser and for a hooklike rib ( Fig. 62A ). The venter is smooth. Fig. 62. Stoyanowites aspinosus Korn & Ghaderi, 2016 . A . Lateral and dorsal view, specimen MB.C.30100, section C, -1.60 m. B . Whorl profile proportions. Scale bar units =1 mm. Table 36. Conch dimensions (partly estimated) and ratios of selected specimens of Stoyanowites aspinosus Korn & Ghaderi in Korn et al. , 2016 from Baghuk Mountain.

Specimen	dm	ww	wh	uw	ah	ww/dm	ww/wh	uw/dm	WER	IZR
MB.C.30100	71.7	13.8	20.4	37.3	19.8	0.19	0.68	0.52	1.91	0.03
MB.C.30100	56.1	10.8	15.5	27.1	–	0.19	0.70	0.48	–	–
MB.C.30097	56.0	–	16.2	26.7	15.7	–	–	0.48	1.93	0.03
MB.C.30099	53.5	11.6	18.4	24.0	16.7	0.22	0.63	0.45	2.11	0.09
MB.C.30098	58.2	12.7	19.1	25.3	18.1	0.22	0.66	0.43	2.11	0.05

Remarks Stoyanowites aspinosus differs from S. dieneri in the absence of dorsolateral nodes and the presence of densely spaced curved riblets on the body chamber. Stoyanowites parallelus sp. nov. differs in the flat venter. Stratigraphic range Upper part of the Hambast Formation; 1.80 to 1.60 m below the extinction horizon ( Alibashites ferdowsii Zone ).