Madagascar Ammonites

[Wrangellian]

I may have already asked this, if so it's been a while and I dont think I got a clear answer: Does anyone know anything about those Cretaceous? Jurassic? Tulear? Mahajanga? Madagascan nacreous ammonites you see for sale everywhere? I have acquired 3 different specimens so far, all different, and have ID'd one as Cleoniceras besairei, and another as possibly Melchiorites sp. but I have found conflicting info on both their age and their location of origin. Some say Tulear, some say Mahajanga, which are nowhere near each other on the map. I suspect most sellers dont know anything about them, they only repeat the info they find elsewhere, some of which may be incorrect. I see other ammonites like Perisphinctes that are definitely Jurassic, also attributed to one or both sites, so maybe one site is Jurassic/Perisphinctes and the other is Cretaceous/Cleoniceras but they tend to get mixed up.

Anyone who can sort this out for me, speak up! Thanks.

[i'm speaking mainly about the unpolished nacreous ones. The polished ones may be from the same place but I dont care about them!]

Eric

Edited March 23, 2011 by Wrangellian

[siteseer]

I'm not an ammonite guy but have gathered that ammonites come out of at least three layers in Madagascar. The Perisphinctes come out of a Middle Jurassic site at/near Tulear. I have a small nautiloid that I bought simply because it was super-cheap and had great info with it except for the exact site. Maybe the label will help you sort out your stuff a little:

Cleoniceras madagascariense Collignon 1949.

Early Cretaceous

Early Aptian (about 115 million years old)

Douvilleiceras inequinolum Zone (spelling might be wrong on the species - it was a handwritten label I had to interpret)

Mahajunga Province, northwestern Madagascar.

One of my friends went nuts when Madagascan ammonites hit the market. He bought smart, obtaining samples of everything and got some good labels from some of the more knowledgeable dealers/collectors. He has told me he doesn't see the variety that used to come out of there - mostly just the commercial Perisphinctes and polished stuff. I can try to get some info from him on my next visit.

Also, there are articles on Madagascan ammonites - try your local university library.

I may have already asked this, if so it's been a while and I dont think I got a clear answer: Does anyone know anything about those Cretaceous? Jurassic? Tulear? Mahajanga? Madagascan nacreous ammonites you see for sale everywhere? I have acquired 3 different specimens so far, all different, and have ID'd one as Cleoniceras besairei, and another as possibly Melchiorites sp. but I have found conflicting info on both their age and their location of origin. Some say Tulear, some say Mahajanga, which are nowhere near each other on the map. I suspect most sellers dont know anything about them, they only repeat the info they find elsewhere, some of which may be incorrect. I see other ammonites like Perisphinctes that are definitely Jurassic, also attributed to one or both sites, so maybe one site is Jurassic/Perisphinctes and the other is Cretaceous/Cleoniceras but they tend to get mixed up.

Anyone who can sort this out for me, speak up! Thanks.

[i'm speaking mainly about the unpolished nacreous ones. The polished ones may be from the same place but I dont care about them!]

Eric

[Han]

Dear friends,

I am no Ammonite hunter as well, but working on the gastropod superfamily Stromboidea.

Because Stromboidea are found on Madagascar as well I have many publications of for example Collignon.

Some of these are:

Collignon M. (1931) - Faune Senoniennes du nord et du l’ouest de Madagascar

Collignon M. (1931) - Paléontologie de Madagascar. XVI. La faune du Cénomanien à fossiles pyriteux du Nord de Madagascar

Collignon M. (1934) - Fossiles Turoniens d’Antantiloky (province d’Analalava, Madagascar)

Collignon M. (1937) - Paleontologie de Madagascar. Les Ammonites pyriteuses d'Aptien d'Antanatanamirafy

Collignon M. (1949) - Faune Neocomienne des Couches a Crioceres de Belohasifaka (Cercle de Sitampiky)

Collignon M. (1951) - a,b - Upper Cretaceous Publications of Madagascar

Collignon M. (1954) - Essai de Nomenclature Stratigrafique des Terrains Sedimentaires de Madagascar

Collignon M. (1960) - Atlas des fossils caractéristiques de Madagascar. Fasc. 6 - Tithonique

Collignon M. (1962) - Atlas des fossiles caractéristiques de Madagascar. Fasc.8. (Berriassian, Valanginien, Hauterivien, Barremien)

Collignon M. (1962) - Atlas des fossiles caractéristiques de Madagascar. Fasc.9. Ammonites

Collignon M. (1962) - Atlas du fossiles caractéristiques de Madagascar. Fasc.8. (Berriassien, Valanginien, Hauterivien, Barremien).

Collignon M. (1962) - Atlas du fossiles caractéristiques de Madagascar. Fasc.9. Aptien

and more.

If you are interested in these publications, let me know. Send your email address and I will send you the publications by "you send it".

best regards,

Han

http://www.stromboidea.de/

Edited March 24, 2011 by Han

[Wrangellian]

Thanks both,

If C. madagascariense is from the same beds as my C. besairei, I'll make my label based on that.

Early Aptian? According to the latest numbers, fyi, that would be no younger than 120my. But the stratig. info I have seen says Early-Mid Albian (112-105my). Hmmmm...

Anyway, If any of those papers are useful regarding these nacreous Madagascan ammonites, I could use it, though I might have some trouble if they're in French (I may be Canadian, but I'm not French Cdn!)

[Wrangellian]

Followup:

According to Sepkoski, Cleoniceras is L-M Albian (that would be 112-~105m.y.) so I got that much right.

If I could just find out if there is a specific location where these all come from, that would satisfy me! Sounds like it is Mahajanga province..

[Diplotomodon]

Those black and white ones? The one I have wasn't labeled, but from sightings in other rock shops they (some of them at least) seem to be of Albian age.

[Wrangellian]

Those black and white ones? The one I have wasn't labeled, but from sightings in other rock shops they (some of them at least) seem to be of Albian age.

I'm not sure about the black and white, I'm talking about the small nacreous (pearly), unpolished ones. They do seem to be Albian age (lower-mid).

So I gather, these are from Mahajanga province in the NW, while the other sandy-colored Jurassic ones are from Tulear (Toliara) in the SW.

[Diplotomodon]

I'm not sure about the black and white, I'm talking about the small nacreous (pearly), unpolished ones. They do seem to be Albian age (lower-mid).

So I gather, these are from Mahajanga province in the NW, while the other sandy-colored Jurassic ones are from Tulear (Toliara) in the SW.

If there are two types of Mahajangan Albian ammonites that nobody can tell which species they are, this is gonna get really confusing

I can't really speak for unpolished nacreous ammonites from Madagascar. Just those other ones (opposite in every way---a bit larger, polished, etc....)

I di some Googling and found only this seller's page that copies-and-pastes info from their previous items rather than even from anywhere else. The only info they give beyond "Cretaceous," "Madagascar," and "GREAT COLOR! EXCEPTIONAL SPECIMEN!" is the "Alpian Formation." I'm assuming that's a total wreck and mispell of Albian which is a geological age not a formation. Google "Alpian formation" and you get only the same page followed by a few other collectors pages who copied it and redirects to Alpine Formation. I can see what you mean.

However, there's a glimmer of hope: This Cleoniceras is listed as coming from the Mahajanga Province, which sort of confirms that.

(Hey, that seller's located in High Bridge NJ! Maybe I can pay him a visit...

[Wrangellian]

That's the trouble I have with the Internet - I do a search for Cleoniceras + Madagascar and I get a million sites -mainly dealers- with all the same shaky info. You'd think there would be at least one educational site out there with a decent guide to the ammonites of Madagascar, but I guess these sites don't make money.

Anyway, the fact that they are both called Cleoniceras (the small unpolished and large polished ones) leads me to think they are both from the same area, depending on the reliability of those IDs. In any case, Sepkoski restricts the genus Cleoniceras to the lower to mid- Albian, so I guess the next step is to figure out where in Madagascar there are Albian fossils..

[desert rat]

Check in at http://www.manzanitalab.com/LabLog for a start at answering your Madgascar ammonite questions.

There is comprehensive identification data on the Cleoniceras clan there.

I'm currently engaged in translating Collignon and posting the translations on the blog.

Then I'll be glad to help out any way I can.

I'll be out tomorrow but available most any time after.

Phil Dunton

Tucson

[Wrangellian]

Thanks, it looks like a good start, but I couldnt find any pictures of them on the site, are you planning to put some up eventually or are they there and I just missed them?

Sounds like I might have to wait yet for info on the Albian ammonites... I have 4 examples now, 2 of which are Cleoniceras, and I still don't know where and what formation they are from! Will bookmark the site. Cheers.

Edited April 21, 2011 by Wrangellian

[desert rat]

Thanks, it looks like a good start, but I couldnt find any pictures of them on the site, are you planning to put some up eventually or are they there and I just missed them?

Sounds like I might have to wait yet for info on the Albian ammonites... I have 4 examples now, 2 of which are Cleoniceras, and I still don't know where and what formation they are from! Will bookmark the site. Cheers.

Sorry for the long delay, I'm not used to checking around as I should.

There are links in the posts to the pictures supplied by Collignon for each species described.

I'm working full-time on translating Collignon's species descriptions for use here. When I complete one I think would be of use to others, I post it in the Manzanita Lab blog.

[desert rat]

That's the trouble I have with the Internet - I do a search for Cleoniceras + Madagascar and I get a million sites -mainly dealers- with all the same shaky info. You'd think there would be at least one educational site out there with a decent guide to the ammonites of Madagascar, but I guess these sites don't make money.

Anyway, the fact that they are both called Cleoniceras (the small unpolished and large polished ones) leads me to think they are both from the same area, depending on the reliability of those IDs. In any case, Sepkoski restricts the genus Cleoniceras to the lower to mid- Albian, so I guess the next step is to figure out where in Madagascar there are Albian fossils..

I am looking at Collignon's "les faunes Albiennes de Madagascar" as I write this. This is the paper in which he originally named Cleoniceras madagascariense and Cleoniceras Besairiei.

Both types came from Ambarimaninga. He presumed at the time, and I don't know any different, that the sedimentary level was Lower Albian.

I DO know that most of the nicely preserved Albian ammonites come from the Mahajunga basin, and that is where Ambarimaninga is.

[Wrangellian]

OK thanks Phil... (Sorry for my delay as well) I see some figures on your page but they aren't clear enough for me to be confident about my IDs and I'm not sure the taxa of all 4 of my specimens are represented there (yet)...

Can you tell what I have by the following pics? You can see a pencil for scale. I believe the one in upper right to be C. besairei but not sure if the upper left is the same species or not (more prominent ribbing)... and the other two, no idea. The lower left has no ribbing at all, just fine growth lines; I saw something similar somewhere online called Melchiorites..? but don't know if I should trust that source.

Edited June 12, 2011 by Wrangellian

[desert rat]

I doubt these are Cleoniceras. Cleoniceras is characterized by a sharper venter than I see in your specimens.

(Read that: "they look too fat.")

If you will take proportional measurements, I might be able to get a closer ID.

Briefly, measure the diameter. Do all measurements at the same cross section point you measured the diameter.

Divide the height of the last whorl by the diameter and give that as Height. As in: ".45".

Then measure the width at the same point and divide THAT by the diameter and give as Width.

Then measure the umbilical opening, if it is a funnel, take two measurements top and bottom, and give each as the Umbilicus. IE. ".20".

I do have this explained with pictures up on the Manzanita Lab Blog.

Post those proportional measurements and perhaps a good close-up of the ornamentation (ribbing) of the large specimen.

We want to know if the ribs curve and if so, which way. Do they cross the venter?

Is there a groove on the ventral surface? Are there larger ribs with tiny lirae in between?

If so, how many between each rib?

I'm thinking Lemuroceras. These are another fairly common family member of the Cleoniceratidae.

In some deposits, they predominate.

[desert rat]

I should probably add that I think I see at least three different genera

in your photos.

The lower right is going to be interesting.

[Wrangellian]

OK thanks, I will try that, but it might have to wait til after the weekend, if I can find a good caliper, but the ribbing does seem to go across the venter, weakly in the upper right specimen but prominently in the others. I dont see any tiny lirae between the larger ribs except on the smallest specimen, crossing the venter but not continuing into the umbilicus. Not sure what you mean about the direction of curve - toward or away from the aperture?

[desert rat]

AHHHHhhhhhh.....

Sorry, I've been off line mostly recently and not checking in.

Han Stoutjesdijk has graciously provided a veritable plethora of info on Madagascar ammonites

and I've been totally engaged in translating the manuscripts sent by Han and updating

my "Descriptions of Species" volume.

Curved: Convex or concave towards the aperture.

Sometimes the ribs/constrictions are biconcave.

Do the "decorations" rise radially from the umbilicus and then abruptly bend forward?

If so, perhaps they straighten back out and cross the venter without drawing a sinus?

Or maybe they "draw" a sharp angled sinus.

Other things to look for:

Do the ribs split (bifurcate) somewhere on the side? Where? In the middle, below the middle ETC.

Cleoniceras (Cleoniceras) species often have small tubercles on the sides.

This is likely to be where a rib bifurcates. So, a compressed ammonite with small tubercles at a bifurcation point might well be a C. (Cleoniceras). It will never be a Cleoniceras (Grycia) which by definition has no tubercles.

These are the type of observations needed to get down to the nitty-gritty of ammonite ID.

A set of proportional measurements and a description of the "ornamentation" as described above

would likely allow ID at least to the genus taxa.

[Wrangellian]

OK, sounds like I could use an intensive course on ammonite morphology before I can get an ID on mine! Maybe with these occasional reminders I'll manage to find a caliper and get the measurements eventually..

[desert rat]

There is a REALLY GOOD introduction to cephalopod morphology (and everything else cephalopod) in the "Treatise On Invertebrate Paleontology (K)Mollusca 3" available from the University of Kansas. Just Google for them or for the "Treatise On Invertebrate Paleontology".

This volume has the needed introduction but does not cover most of what is coming from Madagascar. It covers the nautilus through bactritoidea.

To get the Cretaceous ammonites you need "Treatise on Invertebrate Paleontology L(Mollusca 4 Revised)". I have no financial interest in the university press and can very highly recommend the books.

There is supposed to be a revised volume on the Triassic/Jurassic ammonites "coming out real soon now".

I am completing a compilation of the hundreds of pages of manuscripts Han has sent me. You can't work with manuscripts that were written over a period of 40 years. You always wind up with 5-6 books on the desk, so I have been translating and correcting names/lineages/ETC. to today's standard and pulling it all together in a single working volume. Covers, I think, between 80 and 90% of the species I see coming from Madagascar.

If you like I will mail you a copy in a few weeks as I have only Gaudryceras to complete.

I am afraid a pdf will be humungous to the extreme.

I work with fossils and could use some technical expertise when it comes to putting large documents on the 'net.

So, I am open to suggestions.

[Wrangellian]

OK well I could do any number of things if I had the money, but for now I'm relying on free sources (as limited as these are, I know)... I will get those measurements up soon, maybe tonight now that I'm thinking of it and have gotten other stuff out of the way - I wouldnt mind a copy of your compilation if it doesnt cost me much.

I dont have much expertise in things Internet but hopefully someone else who does will see your message above.

[Wrangellian]

I tried to find your instructions on your website for taking measurements but couldn't... maybe you could add links at the bottom of your various pages that say "See also...", that might make it easier for slow people like me to find things? Just an idea..

Anyway, if I understand the instructions you posted earlier (ie. that the diam. of the umbilicus is divided by the total diameter, as with the width and height of the outer whorl?)... then the measurements I have come up with are:

Upper Left ammonite (Cleoniceras?): Height .416 Width .33 Umbilicus .27

Upper right (biggest): H .46 W .31 U .17

Lower Left (smooth one): H .48 W .397 (=.4?) U .17

Lower right one: H .3 W .24 U .4

Hope I did these right. I'll see if I can get better pics of the ornamentation if you need it. Thanks again.

Edited July 22, 2011 by Wrangellian

[desert rat]

I have the new Manzanita Lab "Description of Species, Nautilidea/Ammonoidea (Madagascar)" available in the downloads section of the www.manzanitalab.com webstore. You will need to set up an account (sorry, the software requires it, do a bogus account if it bothers you, it only checks for a well-formed email addy). All is free.

The file is huge, weighing in at 227 MB it is 274 pages long and contains descriptions, more or less complete, of 250 Malagache ammonoid species. Also includes a few pages on making the measurements.

This is now the desk reference used at our two facilities when working with Madagascar ammonites and nautiloids.

I can have OfficeMax print and spiral bind a copy for $75 post-paid to the lower 48.

The ammonite measurement data is available in the Manzanita Lab Weblog in the "Ammonite Systematics" section.

Go to www.manzanitalab.com/LabLog/ and select the menu selection from the bar below the header pic.

More later.

[desert rat]

Lower left specimen (the smooth one),

appears to be Desmoceras (Desmoceras) latidorsatum MICHELIN var. media WIEDMANN & DIENI, 1968.

It falls well within the parameters for the species.

Maurice Collignon studied more than 300 samples of Desmoceras from Madagascar and found that they seemed to make a fairly continuous spectrum of proportions.

The proportion he settled on was Height/Width.

If H/W <= .80 = latidorsatum obesa REYNES

If H/W .81 - .90 = latidorsatum var. inflata BREISTROFFER

If H/W .91 - 1.10 = latidorsatum sensu stricto MICHELIN

If H/W 1.11 - 1.20 = latidorsatum var. media JACOB (now WIEDMANN & DIENI, 1968.)

If H/w >= 1.21 = latidorsatum var. complanata JACOB

[Wrangellian]

(Hmmmm, thought I already replied but I guess not)..

OK thanks Phil, If I do get your guide it'll have to be the free one.. but the size might be too big for my overstuffed computer and therefore a lot of effort just for my 4 little $2 specimens, but looks like a good thing to have for future reference. Will bookmark your page anyway for when I do get back on this. Cheers.