Baghuknautilus aplomorphus, Korn & Hairapetian, 2025
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 ).
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Kingdom |
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Phylum |
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Class |
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SubClass |
Nautiloidea |
Order |
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SubOrder |
Liroceratina |
SuperFamily |
Liroceratoidea |
Family |
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Genus |