and this is an Anetoceras, 44 mm across, from the Early Devonian of Bundenbach.

Another early ammonoid in pyrite from the German Devonian (17 mm across). Does anybody recognise this? Could it be Erbenoceras?

Beautiful fossils Hajar, can you see the lobes on the "Erbenoceras", it sure looks like a nautiloid.

(I guess its just about as close as an ammonoid can get to a nautiloid )

Thanks Kevin. Yes, this one has the ventral lobe, very much like the Bactrites. Otherwise the suture is very simple. I'll take another photo tomorrow.

Close-ups as promised.

I just came across this description of a current research project on the early ammonoids; http://www.researchportal.ch/unizh/p7824.htm

Dr. Christian Klug identifies the specimen above as Gyroceratites and the Anetoceras is now renamed to Ivoites hunsrueckianum or perhaps Bovites. Thanks!

The phylogram below is from DE BAETS, K., KLUG, C. & KORN, D. (2009): Anetoceratinae (Ammonoidea, Early Devonian) from
the Eifel and Harz Mountains (Germany), with a revision of their genera. – N. Jb. Geol. Paläont. Abh., 252: 361–376.

Here's a fine image to illustrate the "Devonian Nekton Revolution" in which the early ammonoids play a major role. It's from a new paper by Klug et al. (2009) and has the caption "Macroecological steps in the evolution of Palaeozoic marine food webs".

Klug, C., Kroger, B., Kiessling, W., Mullins, G.L., Servais, T., Fryda, J., Korn, D. & Turner, S. 2009: The Devonian nekton revolution. Lethaia, 10.

Thanks for posting that illustration Hajar, it's great. Do they consider the early nautiloids as macro-plankton until they developed tightly coiled shells, then they became nectonic? Any idea which one of the authors is the artist?

Hi Kevin,

This is what they say about early nautiloids:
“Among the nautiloids, all nautiloids originating during the Cambrian, the Actinocerida, Ascocerida, Discosorida, Ellesmerocerida, Endocerida, Lituitida and Oncocerida are here considered demersal; this inference is based on the facies they occur in and morphological features such as coiling and position of hyponomic sinuses (Chen & Teichert 1983; Stridsberg 1985; Westermann 1999; Kroger & Mutvei 2005).”

On orthocerids: “Most orthocerids were probably capable of minor horizontal movements but they were ineffective swimmers and migrated predominantly vertically and/or drifted passively (Hewitt & Watkins 1980; Westermann 1999; Mutvei 2002; Kroger 2003, 2005; Kroger & Mutvei 2005; Mutvei et al. 2007). This is suggested by their poorly differentiated muscle-attachment structures, the absence of significant endosiphonal or endocameral deposits and, in some cases, also shell morphology.”

“The coiled Tarphycerida and Nautilida are interpreted as nektobenthic or nektoplanktonic based on actualistic comparision of the shell form, muscle attachment structures and position of the hyponome (Westermann 1999; Kroger & Mutvei 2005).”

Here below is how they assigned the different animal groups to "ecological megaguilds".

Don't know who the artist is, but I've asked.

Christian Klug is the artist. I'm very impressed.

Thanks again Hajar

It seems to mostly match what I find around here, except that I find Tarphycerids alongside Endocerids in a few locations.

Yes! a very good artist

Maybe he will do one for Dieter and Alan on their Chainman Goniatites Zone paper

I like this Early Devonian Borivites from the abstract book for the Dijon meeting linked to by Kevin.