Dear colleagues,

While studying ammonites from the boreholes drilled in Western Siberia, I found a strange specimen. Its age is Early Valanginian and it is associated with Nikitinoceras and Neotollia. This specimen has pronounced nodes on the midflanks - a feature unknown in Boreal ammonites of this age. On the other hand, its rib pattern differs from those of the Olcostephanidae or Neocomitidae.

Its ribbing in general is closwe to those of Neotollia - except the nodes