Ivö Klack was a small island during the Campanian.
Teeth from large lamniform sharks, such as Cretoxyrhina mantelli and Cretalamna appendiculata, are significantly more common at Ivö Klack than they are in other sites, such as Ignaberga.
The prominence of large sharks in the area probably derives from large sharks requiring large prey, and large marine reptiles being common at Ivö Klack as well.
There are plesiosaur fossils from Ivö Klack with shark bite marks.
Modern great white sharks are known to patrol around small islands inhabited by seals, possibly a behavior also present in the similar Cretoxyrhina.
Ivö Klack is the only site where fossils of hesperornithiforms, a group of aquatic birds, are present.

Fossil remains of large marine reptiles are also especially common at Ivö Klack.
The high diversity of sharks and mosasaurs recovered at Ivö Klack shows that large predators frequented the rocky coastline.
There must have been a productive ecosystem, with a diverse invertebrate fauna attracting small nektonic predators (such as cephalopods and fish), which then in turn attracted larger predators.
It is probable that the richness of the environment also made Ivö Klack a nursery and feeding ground for migratory species, similar to rocky shores today.
The discovery of the basin's only crocodylomorph at Ivö Klack might indicate that Aigialosuchus preferred to live in coastal waters, where it could lay its egg on adjacent land, rest and heat up, similar to modern crocodilians.
Ivö Klack was a small island during the Campanian. Teeth from large lamniform sharks, such as Cretoxyrhina mantelli and Cretalamna appendiculata, are significantly more common at Ivö Klack than they are in other sites, such as Ignaberga. The prominence of large sharks in the area probably derives from large sharks requiring large prey, and large marine reptiles being common at Ivö Klack as well. There are plesiosaur fossils from Ivö Klack with shark bite marks. Modern great white sharks are known to patrol around small islands inhabited by seals, possibly a behavior also present in the similar Cretoxyrhina. Ivö Klack is the only site where fossils of hesperornithiforms, a group of aquatic birds, are present.
Fossil remains of large marine reptiles are also especially common at Ivö Klack. The high diversity of sharks and mosasaurs recovered at Ivö Klack shows that large predators frequented the rocky coastline. There must have been a productive ecosystem, with a diverse invertebrate fauna attracting small nektonic predators (such as cephalopods and fish), which then in turn attracted larger predators. It is probable that the richness of the environment also made Ivö Klack a nursery and feeding ground for migratory species, similar to rocky shores today. The discovery of the basin's only crocodylomorph at Ivö Klack might indicate that Aigialosuchus preferred to live in coastal waters, where it could lay its egg on adjacent land, rest and heat up, similar to modern crocodilians.
Kristianstad Basin