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 Lutites profundus Korn & Hairapetian gen. et sp. nov. urn:lsid:zoobank.org:act: BB88C301-E69F-4E4B-8B25-F086D3BC6EEC Fig. 53 ; Table 27 Diagnosis Species of Lutites gen. nov. with conch reaching 125 mm dm. Subadult stage with subcircular, compressed whorl profile (ww/wh =0.70–0.80) and rounded venter; about 13 coarse ventrolateral nodes per volution. Adult stage with subtrapezoidal, compressed whorl profile (ww/wh =0.70–0.75), flat or concave venter and angular ventrolateral shoulder; weak dorsolateral ribs and elongated ventrolateral nodes. Prongs of external lobe trifid; altogether about 19 notches of E,A and L lobes. Etymology From the Latin ‘ profundus ’, meaning ‘deep’, because of the deep external lobe. Material examined Holotype IRAN • Esfahan Province , Baghuk Mountain E section ; Hambast Formation; illustrated in Fig. 53 ; MB.C.30003 . Paratypes IRAN • 1 specimen ; Esfahan Province , Baghuk Mountain C section ; Hambast Formation ; MB.C.30002 • 1 specimen ; Esfahan Province , Baghuk Mountain E section ; Hambast Formation ; MB.C.30004 • 1 specimen ; Esfahan Province , Baghuk Mountain G section ; Hambast Formation ; MB.C.30005 • 3 specimens ; Esfahan Province , Baghuk Mountain H section ; Hambast Formation ; MB.C.30006 to MB.C.30008 . Description Holotype MB.C.30003 is a rather well-preserved specimen with 86 mm conch diameter, in which two whorls can be studied ( Fig. 53A ). One third of the last volution belongs to the body chamber and the last four septa of the phragmocone are crowded. In the adult stage, the compressed whorl profile (ww/ wh= 0.75) shows a broadly rounded umbilical margin with an oblique umbilical wall. The whorl profile is widest on the inner flank, from where the concave flanks converge towards the angular ventrolateral shoulder. The venter is concave in this growth stage. Half a volution back the venter is flat and another half whorl back, a rounded venter can be seen belonging to a subcircular, compressed whorl section (ww/wh =0.80). The sculpture experiences a change in strength during the last volution. The penultimate volution has ten coarse ventrolateral nodes, which are connected with weak and rounded radial ribs. These nodes become weaker and more numerous at the end of the phragmocone, but they are still present on the body chamber (12 on a distance of 120 degrees). Here, they are elongate and alternate, in their positions, with low umbilical ribs. Fig. 53. Lutites profundus Korn & Hairapetian gen. et sp. nov. A . Lateral and dorsal view, holotype MB.C.30003, section E, float. B . Suture line, holotype MB.C.30003, at 60.0 mm dm, 19.6 mm wh. C . Whorl profile proportions. Abbreviations: see Material and methods. Scale bar units =1 mm. Table 27. Conch dimensions (partly estimated) and ratios of selected specimens of Lutites profundus Korn & Hairapetian gen. et sp. nov. from Baghuk Mountain.

Specimen	dm	ww	wh	uw	ah	ww/dm	ww/wh	uw/dm	WER	IZR
MB.C.30005	95.0	–	32.0	40.4	30.5	–	–	0.43	2.17	0.05
MB.C.30005	65.0	16.5	22.5	27.3	–	0.25	0.73	0.42	–	–
MB.C.30003	86.2	21.2	28.2	37.8	27.7	0.25	0.75	0.44	2.17	0.02
MB.C.30003	60.2	16.2	20.5	24.8	–	0.27	0.79	0.41	–	–
MB.C.30002	78.0	18.0	28.0	33.0	–	0.23	0.64	0.42	–	–

The suture line of the holotype has a narrow and deep external lobe (deeper than the adventive lobe) with parallel flanks in the lower part. Its prongs are parallel-sided with asymmetric base and possesses three small notches. The ventrolateral saddle is narrow and asymmetric; it borders the adventive lobe that is widest near its base. It shows two groups of five very narrow notches. The nearly symmetric and inverted U-shaped lateral saddle is higher than the ventrolateral saddle. The asymmetric lateral lobe with less steep dorsal flank has also two groups of narrow notches, a ventral group with two and a dorsal group with three notches ( Fig. 53B ). Remarks Lutites profundus gen. et sp. nov. is similar to L. lyriformis gen. et sp. nov. but differs in the much coarser sculpture of the terminal body chamber, which shows only very weak ribs in the latter species but ventrolateral nodes in L. profundus gen. et sp. nov. All the other species of Lutites gen. nov. with a slender conch also show a much weaker sculpture. Stratigraphic range Upper part of the Hambast Formation; 1.60 to 1.20 m below the extinction horizon ( Lutites profundus Zone ).