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 Abichites abichi Shevyrev, 1965 Fig. 56 ; Table 30 Abichites abichi Shevyrev, 1965: 181 , pl. 24 fig. 4. Xenodiscus aff. kapila – Stoyanow 1910: 87 , pl. 9 fig. 3. Abichites abichi – Shevyrev 1968: 96 , pl. 4 fig. 4. — Korn & Ghaderi in Korn et al. 2016: 878 , textfig. 35. Diagnosis Species of Abichites with conch reaching 75 mm dm. Subadult stage with subquadrate, weakly depressed to compressed whorl profile (ww/wh =1.20) and slightly flattened venter; with 15 rounded straight ribs on the flanks. Adult stage with quadrate whorl profile (ww/wh =1.00), parallel flanks and flattened venter; with weak rounded ribs on the flanks. Prongs of external lobe usually simple; 7–12 notches of E, A and L lobes. Type material Holotype AZERBAIJAN • Nakhichevan Province , Dorasham 2 section ; Paratirolites Limestone ; illustrated by Shevyrev (1965 : pl. 24 fig. 4); PIN 1252/137 . Material examined IRAN • 4 specimens ; Esfahan Province , Baghuk Mountain 1 section ; Hambast Formation ; MB.C.30019 to MB.C.30022 • 1 specimen ; Esfahan Province , Baghuk Mountain B section ; Hambast Formation ; MB.C.30023 • 5 specimens ; Esfahan Province , Baghuk Mountain C section ; Hambast Formation ; MB.C.30024 to MB.C.30028 • 6 specimens ; Esfahan Province , Baghuk Mountain C section ; Hambast Formation ; MB.C.30029 to MB.C.30034 • 4 specimens ; Esfahan Province , Baghuk Mountain G section ; Hambast Formation ; MB.C.30035 to MB.C.30038 • 2 specimens ; Esfahan Province , Baghuk Mountain H section ; Hambast Formation ; MB.C.30039 to MB.C.30040 . Fig. 56. Abichites abichi Shevyrev, 1965 . A . Lateral and dorsal view, specimen MB.C.30039, section H, -1.30 m. B . Lateral and dorsal view, specimen MB.C.30019, section 1, -0.90 m. C . Suture line, specimen MB.C.30019, at 7.7 mm wh. D . Whorl profile proportions. Abbreviation: see Material and methods. Scale bar units= 1 mm. Table 30. Conch dimensions (partly estimated) and ratios of the holotype of Abichites abichi Shevyrev, 1965 from Baghuk Mountain.

Specimen	dm	ww	wh	uw	ah	ww/dm	ww/wh	uw/dm	WER	IZR
MB.C.30019	39.8	14.4	13.1	16.3	12.7	0.36	1.10	0.41	2.16	0.03
MB.C.30028	47.7	12.2	15.6	20.0	15.0	0.26	0.78	0.42	2.13	0.04
MB.C.30027	47.6	15.7	17.2	19.7	16.5	0.33	0.91	0.41	2.34	0.04
MB.C.30023	46.0	18.9	16.2	20.2	15.2	0.41	1.17	0.44	2.23	0.06
MB.C.30038	45.4	14.6	15.0	18.9	14.0	0.32	0.97	0.42	2.09	0.07
MB.C.30036	37.2	12.3	12.4	15.7	11.6	0.33	0.99	0.42	2.11	0.06

Description Specimen MB.C.30039 has 44 mm diameter and is a fragment of half a volution ( Fig. 56A ). However, it allows the study of the conch shape with a nearly quadrate whorl profile. On half of a volution there are twelve sharp radial ribs, which are coarsest in the outer flank. Specimen MB.C.30019 has 40 mm conch diameter and allows the study of only one volution ( Fig. 56B ). The whorl profile is subtrapezoidal with broadly rounded umbilical margin, weakly converging flanks, a subangular ventrolateral shoulder and a flat venter. The sculpture is weaker than in the first specimen and the ribs are coarsest on the inner flank. The suture line of specimen MB.C.30019 is characterised by a large external lobe, of which the flanks stand parallel in the middle part. Its prongs are narrowly V-shaped and non-serrated. After a ventrolateral saddle that is as wide as the external lobe follow a small, nearly parallel-sided adventive lobe with three notches, a small lateral saddle and a small parallel-sided lateral lobe with three notches ( Fig. 56C ). Remarks Abichites abichi differs from the otherwise similar species A. subtrapezoidalis in the quadrate adult whorl profile (subtrapezoidal in A. subtrapezoidalis ). The body chamber of A. abichi has stronger ribs than A. subtrapezoidalis does. A. alibashiensis has a similar body chamber, but differs from A. abichi in the coarse ventrolateral nodes of the subadult stage. Stratigraphic range Upper part of the Hambast Formation; 1.20 to 0.05 m below the extinction horizon ( Abichites abichi Zone to Arasella minuta Zone ).