From wreck to study ammonite or An Inbetweener

On days when I do not find very much, I tend to also take fossils with me that normally
would not be taking,  this wreck of an Amaltheus is such a case,  found in early April this year :

A wreck of an Amaltheus as found - hope for a salvagable inner whorl ?

A wreck of an Amaltheus as found – hope for a salvagable inner whorl ?

I was hoping for a good inner whorl to salvage and may be something subconsciously
registered as  interesting with this ammonite.I prepped the ammonite this weekend
and noticed (apart from it being a rather nice inner whorl) that it does have
rather strong ribbing :

A 7.4 cm Amaltheus stokesi/bifurcus "inbetweener"

A 7.4 cm Amaltheus stokesi/bifurcus “inbetweener”

So a candidate for Amaltheus bifurcus ?

The “Schlegelmilch” lists the variation for ribs/whorl for Amaltheus bifurcus as from
17 to 26,  and this ammonite fits right in there with 25 ribs at 7.5 cm
(Amaltheus stokesi, the other option, has a lot finer ribbing with 31-44 ribs/whorl)

So case closed – or is it ?

The “Schlegelmilch” also list the umbilical width of the ammonites, with
Amaltheus bifurcus at 34-45 %  and Amaltheus stokesi with 25 – 28 % –
and this ammonite has exactly 28 % !

So it looks like this ammonite is something of an in-betweener, a late A. bifurcus or an
early A. stokesi or even a hybrid, since these ammonite species did occur together.

Whatever it is, I´ve had so much fun prepping and wondering about it, that it´s been
really worth taking the chance with the wreck that it was. It´s so much better not
expecting a lot from a fossil and finding a little jewel hiding in there than expecting
a lot and finding it´s a wreck…

AndyS

 

Leave a comment

3 Comments

  1. adrian

     /  May 10, 2015

    nice and crisp for something that was a wreck

    Reply
  2. adrian

     /  May 12, 2015

    only a bit Andy,i have been doing some redcar stuff Dave gave me,but its all rubbish,no centres or just not complete,only the aritities i posted is any good

    Reply

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