View Full Version : A few ammonites from the dusty old drawers!


Phil
May 24th, 2005, 07:11am
It's been a while since we had a new thread, so here's a few ammonites from the drawers at home. None are particularly spectacular or rare, I'm afraid, but still quite interesting.

If anyone objects to the IDs, please shout! Most were bought so I've just taken it for granted that the identifications are correct.

Desmoceras latidorsatum

Quite a common ammonite, this example hails from Madagascar. It is found all over the world and lived 121-89 million years ago. This particular example is quite nice and retains its original shell material, and faint ribbing can be seen on the shell.

http://www.tonmo.com/forums/attachment.php?attachmentid=828&stc=1

http://www.tonmo.com/forums/attachment.php?attachmentid=829&stc=1

Phil
May 24th, 2005, 07:11am
Quenstedoceras sp.

Found in the Northern Hemisphere only, this particular ammonite hails from Saratov in Russia. It is Jurassic in date and was widespread across Europe from 164-159 million years ago. Males and females vary in shape with the females much more inflated in profile.

http://www.tonmo.com/forums/attachment.php?attachmentid=830&stc=1

http://www.tonmo.com/forums/attachment.php?attachmentid=831&stc=1

Phil
May 24th, 2005, 07:12am
Promicroceras sp.

Promicroceras is a small and heavily ribbed. It is a very common ammonite and is one of the most common types found at Charmouth and Lyme Regis in Dorset, England. Very occasionally examples of Promicroceras are found with anaptychi (jaw apparatus) intact. This little fossil is Lower Jurassic and roughly 200 million years old.

http://www.tonmo.com/forums/attachment.php?attachmentid=833&stc=1

http://www.tonmo.com/forums/attachment.php?attachmentid=832&stc=1

Phil
May 24th, 2005, 07:21am
Aulastephanoceras?

Apologies for the poor quality of this one. Like most ammonites from Kimmeridge in Dorset, England, it has been crushed flat in shale. The date is roughly 155 million, give or take a couple of million.

Due to the poor quality I'm not exactly sure of the ID. I found this one myself when I was about 10 years old on holiday with my parents!

http://www.tonmo.com/forums/attachment.php?attachmentid=835&stc=1

http://www.tonmo.com/forums/attachment.php?attachmentid=834&stc=1

Phil
May 24th, 2005, 12:15pm
Worryingly I seem to have lost the details of this one since my computer crash earlier this year in which I lost many, many files. However, I'm sure I have the details somewhere (hopefully).

This rather splendid ammonite has lappets, lateral extensions either side of the living chamber. They are only found on sexually mature males in some species of ammonite and were probably used for display purposes to attract a mate. They were possibly quite brightly coloured.

http://www.tonmo.com/forums/attachment.php?attachmentid=836&stc=1

Phil
May 24th, 2005, 12:15pm
Otoites sauzei

This little ammonite is extremely globular in shape. When mature it would have also had lappets much as the ammonite above. It is Jurassic in date and this genus lived from 176-169 million years ago. It was found in the Neuquen Basin in Argentina.

Unfortunately it has been slightly broken on one side accounting for the asymmetrical profile.

http://www.tonmo.com/forums/attachment.php?attachmentid=837&stc=1

http://www.tonmo.com/forums/attachment.php?attachmentid=838&stc=1

Phil
May 24th, 2005, 12:16pm
Dichotomosphintes sp. (aka Perisphinctes),

A nice specimen which hails from Madagascar. Dichotomosphintes is a Late Jurassic ammonite which dates to 159-154 million years old.

http://www.tonmo.com/forums/attachment.php?attachmentid=839&stc=1

Phil
May 24th, 2005, 12:16pm
Oh no, I've got a visitor at the front door, this one will have to wait! And just on the last one too.

Here's the pictures anyway for now!

http://www.tonmo.com/forums/attachment.php?attachmentid=840&stc=1

Must make them a cup of tea. Will edit later.

Architeuthoceras
May 25th, 2005, 09:33am
Nice fossils Phil!!!!!

The "Cant remember" specimen looks alot like the Dichotomosphintes sp. (aka Perisphinctes), specimen.

Also, the "cant remember" specimen looks like it had a hard time deciding if it was mature, the two constrictions make it look like it changed its mind a time or two.

8-)

spartacus
May 29th, 2005, 02:09pm
damn nice show Phillipo ! :thumbsup:
Can't remember sure does look a deadringer for a Perisphinctes as ol' Eagle eyes commented, one of my faves as yet absent from my hoard. I'll run you through the Normandy collection on pulling my finger out.

Keef