Dactylioceras (Orthodactylites) semicelatum (Simpson 1843)

Hi Roger,

I was just researching Dactylioceras on Google whereupon I stumbled across this gallery image. I don't know if D. annulatum exists; but if it's from the tenuicostatum zone is certainly can't be a D. annulatum as there's only four 'grey shales Dacs' [D. crosbeyi, D. clevelandicum, D. semicelatum, and D. tenuicostatum]. I think your ammonite is actually a D. semicelatum.

Hi Joe,

I got this ammonite from Byron Blessed from Fossils UK at the Petrefakta here in Germany where he had a stand and just took over the information on the ammonite from him. I figured he knew what he was talking about, but you obviously seem to have your doubts. Is annulatum maybe a synonym?

Roger,

This ammonite is definitely a D. semicelatum - there's no other 'valid' species it can be. I should have made myself clearer earlier, but yes, I am pretty sure it's a synonym for D. semicelatum (or potentially, can't find the paper that confirms which yet, D. tenuicostatum). As far as I am aware D. annulatum is no longer considered valid.

PS. I just found an old post of Byron's in a thread I started here a few years ago where he shows D.annulatum and says that it occurs together with D.semicelatum.

Ooops. Forgot to put in the link:

http://www.google.de/imgres?client=firefox-a&hs=Wlf&sa=X&rls=org.mozilla%3Ade%3Aofficial&channel=sb&biw=1600&bih=753&tbm=isch&tbnid=bECSul7KKjWLBM%3A&imgrefurl=http%3A%2F%2Fwww.thefossilforum.com%2Findex.php%3F%2Ftopic%2F13825-the-area-around-whitby-yorkshire-uk%2Fpage-3&docid=tMIdN8OojLXn6M&itg=1&imgurl=http%3A%2F%2Fi701.photobucket.com%2Falbums%2Fww16%2FTrancepostmortem%2FFossil%252520Perverts%252520Images%2FPort%252520Mulgrave%2FSDC11668.jpg&w=434&h=431&ei=NgwJU8OOB4rZtQbFmIGwBw&zoom=1&iact=rc&dur=4153&page=1&start=0&ndsp=33&ved=0CIoBEK0DMBE

It's on Page 2

Thanks for the link, Roger. I'm following Howarth's 1973, 'The Stratigraphy And Ammonite Fauna Of The Upper Liassic Grey Shales Of The Yorkshire Coast' - there's no mention of D. annulatum; just the aforementioned other four species.

Personally I would consider D. annulatum a synonym of D. semicelatum. I do not believe they occur together as different species, instead, there is just one valid genus.

I don't have that publication myself (Do you have a pdf of it perhaps that you could send me?), but I do know that Byron refers to it. Maybe you should send him a message asking if he knows anything new about that species. Perhaps he could aid you in your research....or you could teach him something new...

PM sent.

I just recieved an answer from Byron and he has corrected the ID and now it's clear that Ammojoe was right in his assumption.