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 ovalis Korn & Hairapetian sp. nov. urn:lsid:zoobank.org:act: 983F405A-033F-49EB-8D75-E5F917F23D86 Fig. 58 ; Table 32 Diagnosis Species of Abichites with conch reaching 85 mm dm. Subadult stage with subcircular, weakly compressed whorl profile (ww/wh =0.80–1.00) and rounded venter; about 12 shallow and rounded radial ribs. Adult stage with parallel sided or weakly trapezoidal, weakly compressed whorl profile (ww/wh =0.80–1.00), rounded venter and narrowly rounded ventrolateral shoulder; shallow wide ribs on the flank. Prongs of external lobe simple; altogether 7–11 notches of E, A and L lobes. Etymology From the Latin ‘ ovalis ’, meaning ‘oval’, because of the oval whorl profile in the subadult stage. Material examined Holotype IRAN • Esfahan Province , Baghuk Mountain B section ; Hambast Formation; illustrated in Fig. 58A ; MB.C.30059 . Paratypes IRAN • 1 specimen ; Esfahan Province , Baghuk Mountain B section ; Hambast Formation ; MB.C.30060 • 3 specimens ; Esfahan Province , Baghuk Mountain C section ; Hambast Formation ; MB.C.30061 to MB.C.30063 • 6 specimens ; Esfahan Province , Baghuk Mountain E section ; Hambast Formation ; MB.C.30064 to MB.C.30069 • 2 specimens ; Esfahan Province , Baghuk Mountain G section ; Hambast Formation ; MB.C.30070 to MB.C.30071 • 1 specimen ; Esfahan Province , Baghuk Mountain H section ; Hambast Formation ; MB.C.30072 . Description Holotype MB.C.30059 is a rather well-preserved specimen with 62 mm conch diameter; the phragmocone diameter is 44 mm and 190 degrees of the body chamber are preserved ( Fig. 58A ). The adult whorl profile is weakly trapezoidal with gently diverging, slightly concave flanks, a rounded ventrolateral shoulder and a slightly flattened but broadly rounded venter. One volution earlier, the whorl profile is subcircular and weakly compressed (ww/wh = 0.90). The sculpture on the phragmocone consists of 12 shallow and rounded radial ribs per volution. They become weaker on the body chamber but develop to elongate, rather sharp nodes on the outer flank. The suture line of holotype MB.C.30059 shows an external lobe with flanks standing parallel in the lower part and diverging in the upper part. The prongs are very narrow, lanceolate and not secondarily serrated. On the outer flank lies the symmetric adventive lobe with semicircular, strongly serrated base; it is followed by a rather high lateral saddle and a parallel-sided lateral lobe with five small notches ( Fig. 58C ). Paratype MB.C.30071 has 60 mm conch diameter and is, with its weakly trapezoidal whorl profile and the general conch shape very similar to the previous one but has a more slender conch (ww/wh =0.85). It shows, in the inner whorls, weak ventrolateral nodes connected to the shallow radial ribs ( Fig. 58B ). Remarks Abichites ovalis sp. nov. closely resembles A. paucinodum , but differs in the whorl profile (diverging flanks in A. ovalis sp. nov. but converging in A. paucinodum ), the wider umbilicus in A. ovalis sp. nov. and in the rounded venter in A. ovalis sp. nov. (flat in A. paucinodum ). Table 32. Conch dimensions (partly estimated) and ratios of selected specimens of Abichites ovalis Korn & Hairapetian sp. nov. from Baghuk Mountain.

Specimen	dm	ww	wh	uw	ah	ww/dm	ww/wh	uw/dm	WER	IZR
MB.C.30059	61.8	18.1	20.4	26.0	19.5	0.29	0.89	0.42	2.13	0.04
MB.C.30071	59.5	16.3	19.7	25.5	18.7	0.27	0.83	0.43	2.13	0.05
MB.C.30061	42.8	14.1	14.7	16.5	14.1	0.33	0.95	0.39	2.22	0.04
MB.C.30060	48.8	14.5	18.1	19.4	17.0	0.30	0.80	0.40	2.35	0.06
MB.C.30065	42.7	10.7	15.0	17.0	14.0	0.25	0.71	0.40	2.21	0.07
MB.C.30064	42.4	13.4	15.4	17.0	14.5	0.32	0.87	0.40	2.31	0.06
MB.C.30070	39.3	12.7	13.8	14.6	13.0	0.32	0.92	0.37	2.23	0.06

Stratigraphic range Upper part of the Hambast Formation; 0.75 to 0.40 m below the extinction horizon ( Abichites stoyanowi Zone to lowest part of the Arasella minuta Zone ).