Eocene belemnites

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Greetings cephalopodologists,

I join this forum with a question about Eocene coleoids.

I found the attached calcitic belemnite in rocks which have always been considered as Eocene. They occur above the basal conglomerates which rest on the Oman ophiolite in Muscat. The belemnite is 40 mm long, 10 mm high and 7 mm wide. There is a symmetrically arranged pair of grooves, one deep, one shallow. The shell around the alveolus (which is empty of phragmocone) is crushed. The preservation of this anterior end of the fossil indicates that it has not been reworked. Accompanying fauna is dominated by a diverse and abundant suite of gastropods and fewer bivalves. Sparse isolated colonial corals (upside down the ones I saw) occur in the interval this one came out of.

So,
1) Does anyone recognize this individual to genus or better? (I can make drawings to clarify the pattern of grooves if this helps)
2) What's current status on the survival of belemnites into the Paleogene?

Thanks for your help!
 

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Architeuthoceras

Architeuthis
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:welcome: to TONMO Hajar

Belemnites senso stricto became extinct at the K/T boundary. Here is an old thread about this subject. Your fossil could possibly be Bayanoteuthis, Here (pdf) it is mentioned from the Eocene (under Belemnitida but taxonomic position uncertain). Another pdf (here) by Neale Monks on Belemnites from Deposits Magazine, says Bayanoteuthis may be a Sea Pen (Coelenterate).

Do you have any photos showing the anterior end any better, a view showing where the phragmocone would have been would be useful.

Hope this helps
 
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Thanks very much Kevin,

Do you have a photo or drawing of Bayanoteuthis? I was browsing yesterday, but couldn't find one.

This individual is solid calcite apart from the anterior where the empty alveolus has collapsed during compaction.

Sea pen seems a wild and bizarre idea - on what evidence? Perhaps I'm about to learn something very new about sea pens!

Attached is a view of the anterior end. You can see the uncrushed guard behind the collapsed section.

Cheers,

Ru
 

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Architeuthoceras

Architeuthis
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It certainly looks like a Belemnite. Are there any Cretaceous or Jurassic formations in the area you found it? Are there any fossils like yours in these formations? Belemnoid guards are very resistant and it is possible that even with the anterior end still intact, or at least as intact as it is, it was reworked from older rocks.
 
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The nearest documented marine Cretaceous lies beneath a thick slab of obducted ocean crust! There is some terrestrial Late Cretaceous above the ophiolite (with dinosaur bones) and then onlapping Paleogene deltaic to shelfal marine deposits.

The fossil is unworn (with delicate grooves preserved), unbored and retains the very thin shell of the anterior part of the guard. Very difficult to envisage this as reworked from older deposits.

Intriguing hey?

Do you have an image of Bayanoteuthis? Neale Monks' posted photo from the NHM didn't seem to be there any more.
 

Architeuthoceras

Architeuthis
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That is a great collection of Coleoids. I find Hematites around here, the others are all new to me. I especially like the pyrite Coleoid from France. Thanks for posting that link.
 

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