Baghuknautilus aplomorphus, Korn & Hairapetian, 2025

Korn, Dieter & Hairapetian, Vachik, 2025, Late Permian nautiloids from Baghuk Mountain (Central Iran), European Journal of Taxonomy 1019, pp. 1-76 : 64-66

publication ID

https://doi.org/10.5852/ejt.2025.1019.3071

publication LSID

lsid:zoobank.org:pub:E24EBF4A-9FE2-47E4-A656-E1698F88BB41

DOI

https://doi.org/10.5281/zenodo.17227819

persistent identifier

https://treatment.plazi.org/id/03E487D4-FFE4-4941-FDCF-5B758769FE3B

treatment provided by

Plazi

scientific name

Baghuknautilus aplomorphus
status

gen. et sp. nov.

Baghuknautilus aplomorphus gen. et sp. nov.

urn:lsid:zoobank.org:act:

Fig. 29 View Fig ; Table 22 View Table 22

Diagnosis

Species of Baghuknautilus gen. nov. with thinly discoidal, involute conch (ww/dm ~0.40; uw/dm ~0.10), weakly compressed whorl profile (ww/wh ~ 0.65) and extremely high coiling rate (WER ~2.55) at a conch diameter of 60 mm. Whorl profile with convex venter, convex and convergent flanks, narrowly rounded umbilical margin, a steep umbilical wall and moderately wide imprint zone ( IZR ~ 0.30). Suture line with a very shallow external lobe and an asymmetric, broadly rounded lateral lobe.

Etymology

From the Greek ‘ἁπλόος’=‘simple’ and ‘μορφή’= ‘form’; because of the rather simple conch morphology.

Type material

Holotype

IRAN – Esfahan Province • Baghuk Mountain; Hambast Formation , Vedioceras beds ( late Wuchiapingian); 2011; Korn et al. leg.; illustrated in Fig. 29A–C View Fig ; MB.C.32146 .

Paratype

IRAN – Esfahan Province • 1 specimen; Baghuk Mountain ; Hambast Formation, Vedioceras beds ( late Wuchiapingian); 2011; Korn et al. leg.; illustrated in Fig. 29D–E View Fig ; MB.C.32147 .

Description

Holotype MB.C.32146 is an incomplete, but on the left side rather well-preserved fully chambered specimen with a conch diameter of 83 mm ( Fig. 29A View Fig ). Some conch parameters can only be reconstructed. The conch is thinly discoidal and involute (ww/dm ~0.40; uw/dm=0.10). The whorl profile is weakly compressed (ww/wh ~0.64) with a convex venter and convex, convergent flanks. The umbilical margin is narrowly rounded and the umbilical wall is steep and convex ( Fig. 29B View Fig ). The last volution possesses about 22 phragmocone chambers (CLI=16.5) with an indication of crowding at the end. The siphuncle has a dorsocentral position. The suture line shows a small and very shallow lobe on venter, a broadly rounded asymmetric lateral lobe with steeper dorsal flanks and a shallow umbilical lobe ( Fig. 29C View Fig ).

Paratype MB.C.32147 is a bilaterally corroded, fully chambered specimen with a conch diameter of 60 mm ( Fig. 29E View Fig ). Some conch parameters on the last half volution can only be reconstructed. The conch is thinly discoidal and involute (ww/dm=0.42; uw/dm =0.12) with an extremely high coiling rate (WER=2.54) and a deep whorl overlap ( IZR = 0.32). The whorl profile is moderately compressed (ww/wh =0.76) with a convex venter and convex convergent flanks ( Fig. 29D View Fig ). The suture line shows a shallow, rounded lobe on venter and a broadly rounded slightly asymmetric lateral lobe with steeper dorsal flanks.

Remarks

Baghuknautilus aplomorphus gen. et sp. nov. differs from Shahrezanautilus ghaderii gen. et sp. nov. by the considerably slenderer conch; the ww/dm ratio is about 0.40 in B. aplomorphus but about 0.60 in S. ghaderii . The coiling rate is much lower in B. aplomorphus (WER higher about 2.50 in comparison with more than 3.00 in S. ghaderii ).

Kingdom

Animalia

Phylum

Mollusca

Class

Cephalopoda

SubClass

Nautiloidea

Order

Nautilida

SubOrder

Liroceratina

SuperFamily

Liroceratoidea

Family

Permonautilidae

Genus

Baghuknautilus

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