Prolyelliceras ulrichi (Knechtel, 1947) a fast-moving nektonic carnivore ammonite from Cretaceous lithified, black, carbonaceous limestone outcrops in Peru.
This specimen shows a pathology, a slight deviation to the side of the siphonal of the ammonite. We see Prolyelliceras from the Albian to Middle Albian from five localities in Peru.
Reference: M. M. Knechtel. 1947. Cephalopoda. In: Mesozoic fossils of the Peruvian Andes, Johns Hopkins University Studies in Geology 15:81-139
W. J. Kennedy and H. C. Klinger. 2008. Cretaceous faunas from Zululand and Natal, South Africa. The ammonite subfamily Lyelliceratinae Spath, 1921. African Natural History 4:57-111. The beauty you see here is in the collection of José Juárez Ruiz