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 Paratirolites coronatus Korn & Ghaderi in Korn et al. , 2016 Fig. 31 ; Table 14 Paratirolites coronatus Korn & Ghaderi in Korn et al. , 2016: 860 , text-figs 17–18. Diagnosis Species of Paratirolites with conch reaching 125 mm dm. Subadult stage with trapezoidal, moderately depressed whorl profile (ww/wh =1.60–1.90) and flattened tectiform venter; 15 coarse conical ventrolateral nodes per volution. Adult stage with extremely trapezoidal and moderately depressed whorl profile (ww/wh =1.60–1.90), flattened tectiform venter and subangular ventrolateral shoulder; weak ventrolateral nodes. Prongs of external lobe trifid or multiply serrated; altogether 11–24 notches of E, A and L lobes. Material examined Holotype IRAN • West Azerbaijan , Aras Valley section ; Paratirolites Limestone , 2.90 m below the top; illustrated by Korn et al. (2016 : text-fig. 17A); MB.C.25095 . Additional material IRAN • 1 specimen ; Esfahan Province , Baghuk Mountain E section ; Hambast Formation ; MB.C.29842 . Fig. 31. Paratirolites coronatus Korn & Ghaderi, 2015 . A . Lateral and dorsal view, specimen MB.C.29842, section E, float. B . Suture line, specimen MB.C.29842, at 48.7 mm dm, 17.8 mm wh. Abbreviations: see Material and methods. Scale bar units=1 mm. Table 14. Conch dimensions (partly estimated) and ratios of Paratirolites coronatus 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.29842	54.5	34.0	19.4	24.6	18.7	0.62	1.75	0.45	2.32	0.04
MB.C.29842	41.2	24.0	12.7	17.9	–	0.58	1.89	0.43	–	–

Description Specimen MB.C.29842 is a fully chambered specimen with 55 mm conch diameter and allows the study of one and a half whorls ( Fig. 31A ). It has a strongly trapezoidal, depressed whorl profile (ww/wh =1.75), weakly sinuous flanks, an angular ventrolateral shoulder and a flattened tectiform venter. Half a volution earlier, the venter is weakly flattened but still rounded and another half volution back, the venter is broadly rounded. The sculpture changes during the last volution of the phragmocone; strong conical nodes at the beginning of this volution are transformed into smaller, longitudinally elongated nodes, which have a position at the ventrolateral shoulder. The suture line of specimen MB.C.29842 has a V-shaped external lobe with concave flanks and symmetric, narrowly V-shaped simple prongs. The ventrolateral saddle is asymmetric and dorsally inclined and the asymmetric, nearly parallel-sided adventive lobe has nine little notches. The lateral lobe is nearly flat at its base and subdivided in small equally sized notches ( Fig. 31B ). Remarks Paratirolites coronatus is the paratirolitid with the widest conch, resulting from the coronate ventrolateral shoulder. Therefore, it cannot be confused with any other species. Paratirolites coronatus differs from P. vediensis and the other species in the more strongly trapezoidal whorl profile of the adult stage. Stratigraphic range Upper part of the Hambast Formation; precise horizon at Baghuk Mountain not known.