Anyone found a good fossil?

Steve O'Shea said:
Oooops, Phil has just corrected me - 'spike' = lappet. I should stick to squid and octopus.

Looking at this again actually I think that this form of spike on the aperture is called a spine. How original! :oops:

Lappets were lobes that projected from either side of the aperture, so I was completely wrong. I should stick to watching TV from the seventies!

Still not having much luck in identifying the specimen, hopefully when I get this CD-Rom on fossil Mollusca soon it may be on there.
 
Quoting most of this out of the treatise: A ventral extension of the peristome (apertural margin) may form a ventral lappet; or the ventral extension may be developed as a long, tapering rostrum.
More common are the paired lateral lappets.
As for an identification, Mortoniceras of the Early Cretaceous has the same kind of mature modification, but it has strong ribs covering it's shell. Pectinatites from the Late Jurassic also has a rostrum like that but it has ribs also. The fossil looks alot like Oxytropidoceras from the Cretaceous, but I don't know what the mature aperture looks like. Need more input for better I.D., any sutures visible?
The other fossils are great, do you have I.D.'s and locality info. on them?
 
Steve O said:
Upper left: Phylloceras sp. Albian (Cretaceous), Madagascar.

Lower left: Lamberticeras sp. Upper Calvian (Jurassic), Russia.

Lower right: Hoploscaphites nicolletii. Fox Hills formation, South Dakota (Late Cretaceous)

Upper right: Desmoceras cf. mahabobokensis, Albian (Cretaceous), Madagascar.

Architeuthoceras said:
do you have I.D.'s and locality info. on them?



Duh!!!!! :oops:
 
Architeuthoceras said:
As for an identification, Mortoniceras of the Early Cretaceous has the same kind of mature modification, but it has strong ribs covering it's shell. Pectinatites from the Late Jurassic also has a rostrum like that but it has ribs also. The fossil looks alot like Oxytropidoceras from the Cretaceous, but I don't know what the mature aperture looks like. Need more input for better I.D., any sutures visible?

Kevin, Phil, Clem, I'll get back to you on this one, but it will be a couple of days away (full swing on something else right now). The shell has many apparent low-profile/gently undulating ribs, but no sutures are apparent. Ta for the input. It's great having a fossil forum!!
Cheers, O
 
Here are some pictures of an excavation I did a few years back. You can see a map of the excavation at this link "map"
The old guy in the picture is me. These are ceratitic ammonoids from the Early Triassic, approx. 240mya, the first picture shows a closeup of one of the sutures.

Enjoy :ammonite:
 
The concentration of fossils is quite incredible, and all a decent size too!

Having worked as an archaeologist it is quite interesting to see that the method of recording distribution of finds is practically the same. We used to lay out a large grid frame on top of a section of a trench and used a plumb-bob to record depth of the objects one would record. This was, of course, in order to plot features and finds so that they could be tied into the overall site plan. I suppose the only real difference with palaeontological plotting is that it is primarily finds orientated whereas with archaeology everything has to recorded from soil horizons to cuts, pits, features, structures and, of course, finds.

I used to love doing that; it really brought out the old artistic skills!

That ceriatite clearly demonstrates how simple the sutures were in these early ammonoids. The later ammonites had much more complex sutures; this 'fingerprint' is unique to each individual ammonite species. I wonder if ceriatites demonstrate a similar diversity? (They must be harder to identify on a species level as the suture is so simple, methinks).

Do you publish your excavation reports, Kevin? (By the way, your web-site is great!)
 
Thanks Phil,

It seems computers have made publishers out of everyone, but I have only co-authored a small article about some fossil sponges I found in the same formation as the ceratites.

Species ID on the triassic ammonoids depends on how specific you want, or need, to be. Most triassic ammonoid sutures are almost identical, shell shape and ornamentation are usually different enough for generic IDs. Being a lumper at the moment let's me group all those ammonoids into two species of two genera, those with ribs, and those without.

I am working on a vertical section thru the beds, will post pictures when I have them, in a few months?

:ammonite:
 
Kevin,

Apologies about the delay in replying.

I was curious to know if you have found any other organisms apart from sponges, ceratites and occasional nautiloids in these deposits, and if you could draw any inferences as to the marine habitat these creatures existed in. I'm really thinking of details such as depth, and whether or not this was a coastal deposit, or one on the continental shelf at the time?

The deposits seem to be very rich indeed. Is this an artifact of a specific event or series of events? For example, is the apparant mass mortality due to a mud slide that gathered up these creatures and deposited them together? Or are these depositions at a natural background mortality rate?

Very interesting stuff!

Phil

P.S. Mind the rattlers!
 
Here are pictures of two specimens of an undescribed ammonoid I found while on vacation in the desert last week. I think they are a form of Kazakhoceras. I took the picture of the sutures with the fossil under water so they would show up better. They are from the Late Mississippian age (Late Early Carboniferous) or about 330my old.

:ammonite:
 

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I wonder how rare this particular ammonoid is?

I'm afraid that I have failed to find out any information on Kazakhoceras, none of my resources mention the thing at all, I'm afraid.

However, have you seen this? I discovered it whilst attempting a search on goniatites. It is a downloadable database called 'Goniat' by Prof. Jurgen Kullman and is an extremely detailed resource on these creatures. Despite downloading all the files I could not get the thing to work, but you may have more luck than me!

Goniat: Palaeozoic Ammonoid Database System
 

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