scientific name for ammonite and parasite

[Dave J]

I'm currently trying to put some scientific names to the specimens in my fossil collection. This may be the first of several posts. I understand that this ammonite has a parasite attached to its shell. Could anyone help me out with the name of the ammonite and the parasite? Could you also give me a rough age? I found this in Lyme Regis, U.K. Thank you in advance 😊

[TqB]

The ammonite is a species of Promicroceras (possibly P. pyritosum though reliable species ID is tricky)  and it has a serpulid worm tube growing along with its coil. Well known from there and an interesting find.

It's from the Black Ven Mudstone Formation, Lower Jurassic, Sinemurian Stage, roughly 195 million years give or take a couple of million. (The age can be pinned down better by the exact species which someone more knowledgeable about ammonites might be able to do.)

See this page and linked ones with it:
https://www.lymeregismuseum.co.uk/related-article/epifaunal-worm-tubes-on-lower-lias-ammonites-results/

Edited June 11 by TqB

[Dave J]

55 minutes ago, TqB said:

The ammonite is a species of Promicroceras (possibly P. pyritosum though reliable species ID is tricky)  and it has a serpulid worm tube growing along with its coil. Well known from there and an interesting find.

It's from the Black Ven Mudstone Formation, Lower Jurassic, Sinemurian Stage, roughly 195 million years give or take a couple of million. (The age can be pinned down better by the exact species which someone more knowledgeable about ammonites might be able to do.)

See this page and linked ones with it:
https://www.lymeregismuseum.co.uk/related-article/epifaunal-worm-tubes-on-lower-lias-ammonites-results/

That's amazing. Thank you very much for the information. I have quite a few pyrite ammonites I found down there which I believe to all be the same species, though I will likely make a post regardless 😄. Thank you again.

[Carl]

If I recall, it is thought that the serpulid is a commensal rather than a parasite.

[Mahnmut]

Thats cool, now I want one (Ammonite with serpulid I mean, not a commensal, though rather than a parasite.)