mmmh, very interesting, but starting from the external mould may be hard to classify the specimen.
You can try to reconstruct the ammonites starting from this external mould by using a plaster cast or, more easy, by using play dough or modelling clay, or dental plasticine...
the result is very interesting...
a negative imprint makes it hard to determine, looks like the Genus Dactylioceras
If Toarcian (which I do not believe) could be a Dumortieria (by the straight, ventrally projected ribs, though the thickening and spacing of the ribs in the outer whorl might suggest an early Hammatoceratinae.
If Bajocian (which looks much more probable) it looks like an early Leptosphinctinae, not far from a true Leptosphinctes or a close genus of the same subfamily.
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