Lutites plicatus Korn & Hairapetian, 2021

Korn, Dieter, Hairapetian, Vachik, Ghaderi, Abbas, Leda, Lucyna, Schobben, Martin & Akbari, Amir, 2021, The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran), European Journal of Taxonomy 776, pp. 1-106 : 85-87

Lutites plicatus Korn & Hairapetian gen. et sp. nov.

urn:lsid:zoobank.org:act:1713B70A-3C3C-4FCD-9827-BBBA6F989797

Fig. 55 ; Table 29

Diagnosis

Species of Lutites gen. nov. with conch reaching 120 mm dm. Subadult stage with oval, compressed whorl profile (ww/wh=0.75) and rounded venter; about 12 radial plications per volution. Adult stage with subtrapezoidal, compressed whorl profile (ww/wh =0.72), weakly concave flanks, flattened venter and subangular ventrolateral shoulder; numerous weak and densely arranged plications and small ventrolateral nodes. Prongs of external lobe multiply serrated; altogether 20 notches of E, A and L lobes.

Etymology

From the Latin ‘ plicatus ’, meaning ‘corrugated’, referring to the dense ribbing.

Material examined

Holotype IRAN • Esfahan Province, Baghuk Mountain E section ; Hambast Formation; illustrated in Fig. 55A ; MB.C.30018 .

Description

Holotype MB.C.30018 is a specimen with 84 mm diameter, of which the last 120 degrees belong to the body chamber ( Fig. 55A ). Nearly one volution of the phragmocone can be studied; at this stage the whorl profile is oval and compressed with a rounded venter. The ornament consists of nearly 20 faint radial plications, which are coarsest near the umbilicus and in the ventrolateral area, where they form weak nodes. The ornament is weaker on the body chamber, where the plications are more numerous. The whorl profile is subtrapezoidal and compressed (ww/wh=0.72) in the adult stage with a rounded umbilical margin, weakly concave flanks and a flattened venter.

The suture line of the holotype has a narrow external lobe with asymmetric, multiply serrated prongs (four and six small notches), an asymmetric and inflated ventrolateral saddle and multiply serrated adventive and lateral lobes ( Fig. 55B ). Both lobes show notches of various size.

Remarks

Lutites plicatus gen. et sp. nov. differs in the shape of the flattened, but convex venter from most of the other species of the genus ( L. lyriformis gen. et sp. nov., L. profundus gen. et sp. nov., L. alius gen. et sp. nov.), which possess a completely flat or even concave venter.

Stratigraphic range

Upper part of the Hambast Formation; horizon unknown.

Figures

Fig. 55. Lutites plicatus Korn & Hairapetian gen. et sp. nov. A. Lateral and dorsal view, holotype MB.C.30018, section E, float. B. Suture line, holotype MB.C.30018, 13.7 mm ww, 18.6 mm wh. Abbreviations: see Material and methods. Scale bar units=1 mm.