Vaccinites (rudist) confirmation

[Quer]

Hi,

This is a detached piece I found in a mountain torrent. Campanian-maastrichtian strata, SE Pyrenees.

My guess is genus Vaccinites, mainly due to the polygonal-shaped pores on the upper valve (which has big diameter: around 15 cm.)

Lower valve is conical, geniculate and broken before its end, allowing its pillars and ligament ridge to show.

Can anyone confirm the genus and, if possible, identify the species? The most common species in the zone is Vaccinites archiaci.

 

[Ludwigia]

I agree with Vaccinites.

[Tidgy's Dad]

Nice find! 

i think you're right! 

[abyssunder]

I would say it might be a Vaccinites species considering the external morphology, but It's not clear where it came from, so the geological age / rudist horizon is unknown. I suppose it might be from late Santonian - early Maastrichtian, mostly Campanian sediments. The upper valve's pore-canal system might be helpful in the ID, but a thin, polished section of the lower valve at 1-2cm below the commissural plane is necessary.
Your specimens has a large diameter which exceeds the range of V. archiaci and the other species described in E. Vincens. 1992. Intraspecific variability in Hippuritidae in the southern Pyrenees, Spain: taxonomic implications. Geologica Romana 28: 119-161, but is in the range of V. robustus (Toucas).

 

[Quer]

Thanks a lot, Ludwigia, Tidgy’s Dad and abyssunder, for your help.

Definitely, I realize that a species’ ID of Hippuritidae is usually impossible without sectioning the lower valve. As I don’t have the equipment to do so, it is maybe time to search for a marble workshop

 

Edit: I've erased part of this message. I confused the article linked by abyssunder with another and that I said was nonsense. My apologies.

Edited February 25, 2018 by Quer
Confusion