Abichites infirmis Korn & Hairapetian 2021, sp. nov.
Creators: name: Korn, Dieter
name: Hairapetian, Vachik
name: Ghaderi, Abbas
name: Leda, Lucyna
name: Schobben, Martin
name: Akbari, Amir
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Cephalopoda
Ammonoidea
Dzhulfitidae
Abichites
Abichites infirmis

description: Abichites infirmis Korn & Hairapetian sp. nov.
urn:lsid:zoobank.org:act: DF627B6D-3446-4B02-89B2-81ED420C876D
Fig. 60; Table 34
Diagnosis
Species of Abichites with conch reaching 50 mm dm. Subadult stage with oval, weakly compressed whorl profile (ww/wh =0.60–0.80) and rounded venter; very weak, rounded nodes. Adult stage with weakly subtrapezoidal, weakly compressed whorl profile (ww/wh =0.60–0.80) with weakly converging flat flanks, weakly flattened venter and narrowly subangular ventrolateral shoulder. Sculpture with faint plications. Prongs of external lobe simple; altogether 5–6 notches of E, A and L lobes.
Etymology
From the Latin ‘ infirmis ’, meaning ‘barely visible’, because of the weak sculpture.
Material examined
Holotype IRAN • Esfahan Province, Baghuk Mountain G section; Hambast Formation, 0.40 m below the top; illustrated in Fig. 60A; MB.C.30086.
Paratypes IRAN • 1 specimen; Esfahan Province, Baghuk Mountain 1 section; Hambast Formation; MB.C.30083 • 1 specimen; Esfahan Province, Baghuk Mountain C section; Hambast Formation; MB.C.30084 • 1 specimen; Esfahan Province, Baghuk Mountain E section; Hambast Formation; MB.C.30085 • 2 specimens; Esfahan Province, Baghuk Mountain G section; Hambast Formation; MB.C.30087 to MB.C.30088.
Description
Holotype MB.C.30086 is a rather well-preserved specimen with 42 mm conch diameter (Fig. 60A). The whorl profile of the body chamber is subtrapezoidal with a narrowly rounded umbilical margin, flat and weakly converging flanks, a subangular ventrolateral shoulder and a flattened but still broadly rounded venter. Its ww/wh ratio is 0.70 and the whorl embraces the preceding one only weakly. The shell appears to be smooth except for very faint plications.
The suture line of the holotype has a parallel-sided external lobe that has a width/depth ratio of ~ 0.75. It is deeper than the adventive lobe and possesses unsubdivided lanceolate prongs. The ventrolateral saddle is inverted U-shaped and symmetric and the weakly asymmetric, parallel-sided adventive lobe is subdivided into two secondary notches. The narrow lateral saddle is also inverted U-shaped and followed by a parallel-sided lateral lobe with two notches (Fig. 60B).
Remarks
Abichites infirmis differs from most of the species of the genus in the lack of coarse ribs or nodes. Similar species are A. paucinodus (which possesses few coarse nodes on the flanks) and A. terminalis (with an oval whorl profile).
Stratigraphic range
Upper part of the Hambast Formation; 0.40 to 0.05 m below the extinction horizon (Arasella minuta Zone).
description: Published as part of Korn, Dieter, Hairapetian, Vachik, Ghaderi, Abbas, Leda, Lucyna, Schobben, Martin & Akbari, Amir, 2021, The Changhsingian (Late Permian) ammonoids from Baghuk Mountain (Central Iran), pp. 1-106 in European Journal of Taxonomy 776 on pages 96-97, DOI: 10.5852/ejt.2021.776.1559, http://zenodo.org/record/5604715