Ammonites of the Paleocene

The Ammonites were once a large group of Cephalopods (the same group as octopus, squid and cuttlefish) that ruled the Mesozoic waters. This was untill, the fateful Asteroid hit. However, Ammonites actually managed to survive the asteroid and went on to survive another million or so years into the Cenozoic before dying out completely. Here however, they were similarly diminished, down to just 2 families. Here however, they actually managed to recover and begin to diversify in the Paleocene. Finding the oceans empty, the 2 surviving families, Baculitidae (a family with very straight shells) and Scaphitidae (the more "traditional" ammonites) began to diversify. The most common genus of Scaphitid in the Paleocene is Paleoscaphus (left) . This genus has at the very least 15 species at this time, ranging from no larger than a few centimeters to the massive Paleoscaphus giganteus (pictured here), with shell widths reaching upwards of half a meter, an impressive feat considering how soon after the asteroid impact it arose. One of the few species found outside of Paleoscaphus is inside of the monotypic genus Toxicoscaphus (right). Toxicoscaphus typically inhabits shallower waters, but is interesting in not where it lives, but for its coloration. With it only being a few centimeters across, it is midly toxic and has bright coloration, adapting a similar strategy to the modern Blue Ringed Octopus. The bright colors serve as warning to any potential predators that this would be a yucky meal. All Ammonites of the Paleocene are most typically preyed apon by small sharks, large fish, and plesiosaurs. 

(Submission by Mistercdp)