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 vediensis Shevyrev, 1965 Figs 28–29 ; Table 12 Paratirolites vediensis Shevyrev, 1965: 176 , pl. 23 fig. 1. Paratirolites vediensis – Shevyrev 1968: 92 , pl. 5 fig. 1. — Stepanov et al. 1969 : pl. 13 fig. 5. — Korn in Ghaderi et al. 2014 : text-fig. 7g . — Korn & Ghaderi in Korn et al. 2016: 864 , text-figs 23–24. Diagnosis Species of Paratirolites with conch reaching 250 mm dm. Subadult stage with trapezoidal, weakly depressed whorl profile (ww/wh = 1.20–1.50) and flattened tectiform venter; 10–15 coarse ventrolateral nodes per volution. Adult stage with strongly trapezoidal and weakly depressed whorl profile (ww/ wh= 1.00–1.20), flattened tectiform venter and angular ventrolateral shoulder; weak ventrolateral nodes. Prongs of external lobe usually multiply serrated; altogether 12–20 notches of E, A and L lobes. Type material Holotype ARMENIA • 1 specimen ; Vedi ; Paratirolites Limestone ; illustrated by Shevyrev (1965 : pl. 23 fig.1); PIN 1478/2 . Material examined IRAN • 6 specimens ; Esfahan Province , Baghuk Mountain 1 section ; Hambast Formation ; MB.C.29785 to MB.C.29790 • 1 specimen ; Esfahan Province , Baghuk Mountain A section ; Hambast Formation ; MB.C.29791 • 4 specimens ; Esfahan Province , Baghuk Mountain C section ; Hambast Formation ; MB.C.29792 to MB.C.29795 • 4 specimens ; Esfahan Province , Baghuk Mountain E section ; Hambast Formation ; MB.C.29796 to MB.C.29799 • 6 specimens ; Esfahan Province , Baghuk Mountain G section ; Hambast Formation ; MB.C.29800 to MB.C.29805 • 5 specimens ; Esfahan Province , Baghuk Mountain H section ; Hambast Formation ; MB.C.29806 to MB.C.29810 • 2 specimens ; Esfahan Province , Baghuk Mountain section ; Hambast Formation ; MB.C.29811 to MB.C.29812 . Fig. 28. Paratirolites vediensis Shevyrev, 1965 , lateral and dorsal views. A . Specimen MB.C.29804, section G, -2.75 m. B . Specimen MB.C.29798, section E, float. Scale bar units= 1 mm. Description Specimens MB.C.29811 and MB.C.29794 are the largest specimens with terminal phragmocone diameters of approximately 85 mm . They indicate that the maximum diameter including body chamber has been about 155 mm . Unfortunately, both specimens are poorly preserved. Specimen MB.C.29804 ( 100 mm dm; Fig. 28A ) shows septal crowding at a phragmocone diameter of 65 mm , which means that the maximum conch diameter was approximately 120 mm . It is slightly corroded but shows that the shape of the whorl profile is trapezoidal in the subadult and adult stage. The venter becomes flat with an angular ventrolateral shoulder during formation of the terminal body chamber but is more flattened in the phragmocone stage. The specimen shows a sculpture of the phragmocone that consists of 12 coarse conical nodes on the ventrolateral shoulder and both specimens demonstrate that these nodes become continuously weaker and more numerous (15 on half a volution in) on the body chamber. Specimen MB.C.29798 ( 88 mm dm; Fig. 28B ) closely resembles specimen MB.C.29804 but possesses more longitudinally elongate ventrolateral spines. Fig. 29. Paratirolites vediensis Shevyrev, 1965 . A–B . Lateral and dorsal views. A . Specimen MB.C.29792, section C, -2.75 m. B . Specimen MB.C.29785, section 1, -2.80 m. – C–D . Suture lines. C . Specimen MB.C.29792, at 13.0 mm wh. D . Specimen MB.C.29785, at 12.8 mm wh. – E . Whorl profile proportions. Abbreviations: see Material and methods. Scale bar units= 1 mm. Table 12. Conch dimensions (partly estimated) and ratios of selected specimens of Paratirolites vediensis Shevyrev, 1965 from Baghuk Mountain.

Specimen	dm	ww	wh	uw	ah	ww/dm	ww/wh	uw/dm	WER	IZR
MB.C.29804	99.2	38.8	35.2	40.0	31.5	0.39	1.10	0.40	2.15	0.11
MB.C.29810	94.0	34.0	31.0	39.0	29.0	0.36	1.10	0.41	2.09	0.06
MB.C.29795	79.5	38.0	26.5	33.2	24.2	0.48	1.43	0.42	2.07	0.09
MB.C.29799	73.2	32.0	25.0	31.0	24.0	0.44	1.28	0.42	2.21	0.04
MB.C.29801	71.5	32.0	25.7	29.3	–	0.45	1.25	0.41	–	–
MB.C.29807	70.5	34.2	22.6	31.2	20.3	0.49	1.51	0.44	1.97	0.10
MB.C.29792	49.9	27.9	16.9	22.0	15.5	0.56	1.65	0.44	2.10	0.08
MB.C.29785	48.7	28.7	17.7	20.0	16.2	0.59	1.62	0.41	2.25	0.08
MB.C.29794	121.0	46.0	40.0	52.0	36.0	0.38	1.15	0.43	2.03	0.10
MB.C.29797	106.0	40.0	35.5	46.0	34.0	0.38	1.13	0.43	2.17	0.04
MB.C.29798	89.0	31.5	31.8	34.7	30.5	0.35	0.99	0.39	2.31	0.04

The two smaller specimens MB.C.29792 ( Fig. 29A ) and MB.C.29785 ( Fig. 29B ), both with about 50 mm conch diameter, are rather well preserved phragmocones. Both possess trapezoidal whorl profiles (ww/ wh= 1.65–1.75) with strongly diverging flattened flanks, a subangular or angular ventrolateral shoulder and a slightly flattened, tectiform venter. The sculpture consists of 11 or 12 spiny ventrolateral nodes per volution, which begin as isolated nodes and develop to spiny nodes that show a rib-alike elongation toward the umbilicus. The suture lines of the two specimens resemble each other ( Fig. 29C–D ) and possess a parallel-sided external lobe that is as deep as the adventive lobe. Its prongs are narrow and parallel-sided with three small notches. The ventrolateral saddle is inflated and asymmetric and the lateral saddle reaches only half the height of the ventrolateral saddle. The adventive lobe is asymmetric in both specimens and dorsally inclined; it is serrated with 6 and 8 little notches, respectively. Remarks The material from Baghuk Mountain closely resembles, in conch shape and ornament, the material from the type area near Julfa , but differs in the maximum conch size. While the maximum phragmocone diameter of the Julfa material ranges between 70 and 128 dm (Korn & Ghederi in Korn et al. 2016 ), the Baghuk Mountain material reaches 85 mm only. Paratirolites vediensis differs from P. kittli in the strongly trapezoidal whorl profile with a flattened venter of the subadult stage, which shows a rounded venter in P. kittli . It differs from P. trapezoidalis , which possesses a very similar conch geometry, in the much coarser ribs of the adult stage (which in P. trapezoidalis are much more numerous and delicate), and in the stronger serrated prongs of the external lobes (usually multiply serrated in P. vediensis , but simple or bifid in P. trapezoidalis ). Stratigraphic range Upper part of the Hambast Formation; 3.10 to 2.40 m below the extinction horizon ( Paratirolites kittli Zone ).