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 paucis
Korn & Hairapetian
gen. et sp. nov.
urn:lsid:zoobank.org:act:
9C85D567-DA54-463F-8CE3-BFDBABD83928
Fig. 50
;
Table 25
Diagnosis
Species of
Lutites
gen. nov.
with conch reaching
70 mm
dm. Subadult stage with circular, slightly compressed whorl profile (ww/wh =0.90–1.00) and broadly rounded venter; very coarse conical ventrolateral nodes. Adult stage with subtrapezoidal, slightly compressed whorl profile (ww/wh =0.80), flattened venter and subangular ventrolateral shoulder; without ribs or nodes. Prongs of external lobe simple; altogether 11 notches of E, A and L lobes.
Etymology
From the Latin ‘
paucis
’, meaning ‘fewer’, because of the low number of lobes and nodes.
Material examined
Holotype
IRAN
•
Esfahan Province
,
Baghuk Mountain C section
; Hambast Formation,
2.45 m
below the top; illustrated in
Fig. 50A
;
MB.C.29991
.
Paratypes
IRAN
•
2 specimens
;
Esfahan Province
,
Baghuk Mountain C section
;
Hambast Formation
;
MB.C.29992
to
MB.C.29993
.
Description
Holotype
MB.C.29991 is a partly corroded specimen with
64 mm
conch diameter with two thirds of the last volution belonging to the body chamber (
Fig. 50A
). At the end of the body chamber, the whorl profile is subtrapezoidal with a broadly rounded umbilical margin, converging flanks, a narrowly rounded ventrolateral shoulder and a flattened venter. By contrast, the whorl profile is trapezoidal at the beginning of the body chamber and subcircular in the last portion of the phragmocone. The sculpture of the phragmocone consists of very coarse conical ventrolateral nodes (eight per volution). The body chamber appears to be smooth.
Fig. 50.
Lutites paucis
Korn & Hairapetian
gen. et sp. nov.
A
. Lateral and dorsal view, holotype MB.C.29991, section C, -2.45 m.
B
. Suture line, holotype MB.C.29991, at 13.7 mm wh. Abbreviation: see Material and methods. Scale bar units =1 mm.
Table 25.
Conch dimensions (partly estimated) and ratios of the holotype of
Lutites paucis
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.29991 |
64.3 |
18.8 |
23.5 |
24.1 |
22.8 |
0.29 |
0.80 |
0.37 |
2.40 |
0.03 |
| MB.C.29991 |
44.3 |
15.9 |
16.7 |
16.9 |
– |
0.36 |
0.95 |
0.38 |
– |
– |
The suture line of the
holotype
has a large external lobe with weakly diverging flanks and simple, narrow and lanceolate prongs. The ventrolateral saddle is narrowly rounded and the lateral saddle is weakly inflated. Both the adventive lobe and the lateral lobe are parallel-sided and both characterised by five notches that are very dissimilar in size (
Fig. 50B
).
Remarks
Lutites paucis
gen. et sp. nov.
differs from the other species of the genus in the stouter conch, the only weakly flattened venter and the lower number of conical nodes. The new species may represent an intermediate form between
Alibashites
and
Lutites
gen. nov.
Stratigraphic range
Upper part of the Hambast Formation;
2.45 m
to
1.20 m
below the extinction horizon (uppermost part of the
Paratirolites kittli
Zone
to the
Lutites profundus
Zone
).