Nanaimo Gp Ammonite

[Wrangellian]

A couple weekends ago I really abused myself getting this one out, finished just before sundown... Residential area so I'm glad no one came out to complain. It was worth the toil.

I don't expect an ID on this one but just in the off-chance some of our Island members are viewing I'd be interested to hear opinions. As far as I know this kind of ammo only comes from that one little site, where I get the noded baculites from though there is a similar pahcydiscid from the Browns Riv up-Island. I'm pretty sure it is Haslam Fm as I have found Epigoniceras (Tetragonites) there and reportedly a Hauericeras came out of there, but otherwise the assemblage is not your typical Haslam...

Max diam. ~13cm

[fossisle]

I would say Hypophylloceras surya

[Wrangellian]

I don't think it's any kind of Phylloceras, it is shaped and sized like a typical pachydiscid though if you have some pics to show me I could change my mind? I have some Hypophylloceras and they always have fine, evenly spaces lines and no nodes though I am not versed in the different species.

BTW are you familiar with that one from the Browns Riv. that looks similar to this? I should try and get some photos for people to compare.

Edited April 2, 2013 by Wrangellian

[Terry Dactyll]

Nice find... good luck with the ID & prep....

[Shamalama]

That is a cool looking Ammo!

[FossilDAWG]

Not sure about the ammonite, but I've got a reference or two to check when I get home. Is this from the same level as the trombone-shaped heteromorphs?

I do have a question about Hypophylloceras, though. I notice that both Wrangellian and fossile use this generic name. I thought the Nanaimo Group phyllocerids were Neophylloceras; that's how they are referred to in Usher's monograph, in Jeletzky's papers, and in various papers by Ward and by Haggart. Has somebody synonymized Hypophylloceras with Neophylloceras? I have a Hypophylloceras from Haida Gwaii, and I admit it isn't obvious to me how it differs from Neophylloceras, but even so I am not aware of the Upper Cretaceous Neophylloceras being formally transferred to Hypophylloceras, which I though was a Lower Cretaceous genus.

Don

[Ludwigia]

Interesting how the shell appears to be crushed at certain points. Is that typical for that site? Nice find, by the way.

Edited April 2, 2013 by Ludwigia

[Wrangellian]

Not sure about the ammonite, but I've got a reference or two to check when I get home. Is this from the same level as the trombone-shaped heteromorphs?

I do have a question about Hypophylloceras, though. I notice that both Wrangellian and fossile use this generic name. I thought the Nanaimo Group phyllocerids were Neophylloceras; that's how they are referred to in Usher's monograph, in Jeletzky's papers, and in various papers by Ward and by Haggart. Has somebody synonymized Hypophylloceras with Neophylloceras? I have a Hypophylloceras from Haida Gwaii, and I admit it isn't obvious to me how it differs from Neophylloceras, but even so I am not aware of the Upper Cretaceous Neophylloceras being formally transferred to Hypophylloceras, which I though was a Lower Cretaceous genus.

Don

I only call it that because that's the name used by the guys in the VicPS who were more knowledgeable than myself - otherwise I can't tell the difference either! There didn't seem to be much certainty around it.

Going by my limited sources, Sepkoski says Neophylloceras is Maastrichtian (though I think that will have to be revised to 'Upper Campanian' if Hornby is the source for those), while everything below that (Santonian etc) was either Phylloceras or (VicPS) Hypophylloceras. If you are right that the Haslam contains Neophylloceras then Sepskoski will have to extend that range even more.

This ammo isn't from Mt Tzuhalem where the trombone heteromorphs that I have posted are from, but I did find a Pseudoxybeloceras just below these beds.

Edited April 2, 2013 by Wrangellian

[Wrangellian]

Interesting how the shell appears to be crushed at certain points. Is that typical for that site? Nice find, by the way.

Thanks, Partial crushing is typical of a lot of the Haslam this part of the Island but the indenting along the outer margin is unusual - usually they're crushed flatways. I would guess they would need to be buried vertically to be crushed that way but this one appeared to be laid down horizontally with the bedding plane! Guess it was just an air pocket before compaction.

[Wrangellian]

Boy, things get buried on the 2nd page fast...

Here are some of the ammos from the Browns River for comparison:

diam. ~11cm

smaller one diam ~10cm

profile of 2nd one in pic above - classic Canadoceras profile, like #1

The one in upper left (2 views - diam.3.5cm) I think is different than the others, it is fatter and I think more ribbing

I think this one is a Eupachydiscus haradai or similar -diam ~12.5cm

They're all a little different but similar enough I can't distinguish them by name!

Edited April 5, 2013 by Wrangellian

[Ludwigia]

They're all a little different but similar enough I can't distinguish them by name!

You're talking about the woes of a typical ammonite collector. I sympathize with you and try to comfort you in suggesting that they're perhaps all variations of one developing species or related forms thereof in the end. We however have to deal with the fact that many of the earlier palaeontologists who gave them their names originally were bent on creating a new species based on only slight deviations from similar forms. Fortunately, nowadays an increasing number of experts are remerging similar species back together into one and calling the variations "forma" or "morpha", which is an initiative which I happily greet.

PS. I'm off for the weekend now, so don't get upset if I don't react immediately.

Edited April 5, 2013 by Ludwigia

[Wrangellian]

That makes sense... Still I don't mind putting any of the accepted names on these and if they end up being merged the label can be rewritten. I should reword what I said earlier: I can see enough differences between say the Browns Riv. ammo with the broadly-spaced ribs with finer growth lines in between, and the one from near me that I started this thread with, which has fine growth lines all the way around but nodes near the inner edge of whorls. I could imagine these being different species.. The trouble is I can't see any pictures that match either of them quite well enough for me to be confident of that ID. The pics can be more similar to each other not because the ammos are different forms of the same species but because of the pic quality (or the figured specimen's quality).

That was a bit wordy but that's what happens when I don't know what to think.

[Ludwigia]

Another difficulty is of course that there are often transitional forms between 2 similar looking species and you're not sure in which direction to place them. So, now I'm really on my way now. Off to Bielefeld and Osnabruck to go collecting with Soenke and some other friends.

[fossisle]

Boy, things get buried on the 2nd page fast...

Here are some of the ammos from the Browns River for comparison:

BR Pachydiscid1.jpg diam. ~11cm

BR ammos.jpg smaller one diam ~10cm

BR ammos2.jpg profile of 2nd one in pic above - classic Canadoceras profile, like #1

BR ammos3.jpg The one in upper left (2 views - diam.3.5cm) I think is different than the others, it is fatter and I think more ribbing

BR Eupachy.jpg I think this one is a Eupachydiscus haradai or similar -diam ~12.5cm

They're all a little different but similar enough I can't distinguish them by name!

I think the "fatter" one I would call Menuites.

The rest Eupachydiscus.

Edited April 5, 2013 by fossisle

[Wrangellian]

The small fatter one is Menuites? I have never seen that name!

What species of Eupachy would these be, then? It's not haradai.

[fossisle]

The small fatter one is Menuites? I have never seen that name!

What species of Eupachy would these be, then? It's not haradai.

I would say perplicatus but there are others depending on the ribbing. E. elkhornensis, E. buckhami

Edited April 5, 2013 by fossisle

[Wrangellian]

What papers/guides are you referring to for these? I see these names in Usher 1952 and but none of them seem to match to my satisfaction. The small fat one looks like the (Eu)pachydiscus perplicatus from Usher (plate XIII) but the other small ones seem thinner (squashed?) Actually the pic that the little fat one seems to fit best is the P. ootacodensis in plate XVII but I don't think it's from Hornby, it looks more like the Browns material.

The larger ones are quite different in their ribbing. I'm going to label the small ones perplicatus for now and leave the larger ones blank.

[fossisle]

Not sure about the ammonite, but I've got a reference or two to check when I get home. Is this from the same level as the trombone-shaped heteromorphs?

I do have a question about Hypophylloceras, though. I notice that both Wrangellian and fossile use this generic name. I thought the Nanaimo Group phyllocerids were Neophylloceras; that's how they are referred to in Usher's monograph, in Jeletzky's papers, and in various papers by Ward and by Haggart. Has somebody synonymized Hypophylloceras with Neophylloceras? I have a Hypophylloceras from Haida Gwaii, and I admit it isn't obvious to me how it differs from Neophylloceras, but even so I am not aware of the Upper Cretaceous Neophylloceras being formally transferred to Hypophylloceras, which I though was a Lower Cretaceous genus.

Don

Yes Jim Haggart in his 1989 New and Revised Ammonites from British Columbia and Washington.