A new Amaltheus species for the collection

Amaltheus gloriosus HYATT, 38 mm diameter

Amaltheus gloriosus HYATT, 38 mm diameter

I found a species new to my collection today – in the drawer !
After almost 25 years collecting on the Yorkshire coast, finding a species that I do not have yet in my collection does not happen very often.
I was labeling some finds that I had prepped recently and was sorting them into the appropriate drawer, when I looked again at an ammonite that
I had found at Hawsker in the summer last year. I remember the circumstances of that find very well, there was a piece of dark shale that had fallen from somewhere higher in the cliff, and the piece looked like it came from the upper lias. There was a small greyish nodule embedded in that piece of shale and something that looked like a separate, non-nodularized whorl of a flat ammonite beside it. The nodule looked like it was rebedded, it had what looks like cracks on the outside that had been filled again with shale material. I got curious and split the nodule – and was surpized to find a small Amaltheus inside. The separate piece of ammonite whorl looked very worn and I could not really identify what it was.

Back at home I prepped the little ammonite, put a label of “Amaltheus subnodosus” on it and forgot all about it.

So when I saw it again this morning, I took it out of the drawer and decided to take a second look…it looked different.
Counting the ribs I found it had 12 ribs at around 20 mm, and 17 ribs at around 35 mm, compared to an A. subnodosus with 16 ribs at 20 mm and 21 ribs at 34 mm.

On the inner whorls the tubercles are very strong and almost elongated, the tubercles almost are the ribs, on an A. subnodosus they are a lot less strong.

Direct comparison between Amaltheus gloriosus (left) and similarliy sized Amaltheus subnodosus (right)

Direct comparison between Amaltheus gloriosus (left) and similarliy sized Amaltheus subnodosus (right)

My conclusion is that this ammonite is an Amaltheus gloriosus HYATT, 1867.

Rib density matches well with what HOWARTH documented for another Hawsker specimen, as does the given description and a figure mentioned from QUENSTEDT´s
“Der Jura” (table 20, fig. 9-12). A very good match was also found in A.E. Richter´s Book “Südfrankreich und seine Fossilien”, page 69 fig 49.

And that´s one more ammonite off the “wants list”- the Yorkshire coast never ceases to surprise me !

AndyS

Literature

M.K. HOWARTH 1957, The Ammonites of the Family Amaltheidae in Britain, Palaeontographical Society

F.A. QUENSTEDT 1858, Der Jura, Reprint Goldschneck Verlag 1987
A.E. RICHTER, Südfrankreich und seine Fossilien, Kosmos Frankh 1979
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3 Comments

  1. Great story, thanks for sharing Andy. I wonder how many surprising specimens we all have in our collections.

    Reply
  2. malcolm sharp.

     /  June 19, 2014

    hi great and very interesting, got the name for the ammonite of gb fossils, new to fossling 4 years,i have three which i have found, one 1000mm, i love it, and two very small ones, great to see the photos, thanks mal.

    Reply

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