The land contact between North and South America has lengthy been a fountain of analysis. The Isthmus of Panama — the slender strip of land between the 2 continents — absolutely emerged about 3.5 million years in the past. It allowed contact between terrestrial North and South American mammals, and resulted in wide-scale invasions of placental mammals into South America and the final word extinction of most southern marsupials.
Within the late Jurassic, 150 million years in the past, Earth was rising from a comparatively cool interval, the supercontinent Pangea was breaking apart, and a spike in extinction depth rippled throughout the ecosystems. Throughout the next interval, generally known as the Early Cretaceous, the planet was warming, world sea ranges and atmospheric oxygen had been rising and the continents continued to fragment.
In consequence, two totally remoted oceans, the Japanese Pacific and the Western Tethys, which might later turn out to be the Atlantic Ocean, got here collectively throughout the Hispanic Hall. This union of oceans throughout a time of comparatively excessive temperatures created an ideal storm for ecosystem evolution and drivers for novel biodiversity within the Neotropics — an occasion that might rework the course of marine ecosystems for the subsequent 60 million years.
(Local weather Archive), Creator offered
Our analysis workforce, consisting of scientists from Colombia, Canada and Germany, explored the Neotropics by utilizing the fossil report from the Paja Formation, a poorly studied shallow marine deposit in central Colombia that was laid down simply after the formation of the Hispanic Hall. Our primary objective is to grasp the origin and evolution of this marine ecosystem, and if it served as a possible historic biodiversity hotspot — an epicentre for brand new species to originate and flourish.
We found a brand new species of ichthyosaur, the large fish-like marine reptile. Whereas inspecting a fantastically preserved cranium specimen of the species we named Kyhytysuka sachicarum, we acknowledged this to be the primary Cretaceous hypercarnivore ichthyosaur.
(Cortés, Maxwell, Larsson), Creator offered
The brand new species advanced from Jurassic ichthyosaurs within the Tethys, however differed in that it had distinctive tooth for an ichthyosaur: there have been a number of totally different tooth shapes that served totally different functions, starting from piercing to saw-tooth slicing to crushing.
This massive ichthyosaur represents a revival of hypercarnivory (consuming giant prey). Though some early evolving ichthyosaurs did this, they moved to small fishes and invertebrates for the subsequent 70 million years. Kyhytysuka in some way re-evolved the capability for hypercarnivory throughout this time and place of intense ecological upheaval.
Giant marine animals
Kyhytysuka was additionally one of many final surviving ichthyosaurs. Most ichthyosaurs went extinct by the top of the Jurassic — just a few made it into the Cretaceous however none survived previous 100 million years in the past. The fossil report within the Paja Formation preserves hints of the altering marine ecosystem.
These rocks protect a few of the largest marine animals ever found, together with a number of ichthyosaurs, monumental whale-sized pliosaurs, the primary long-necked elasmosaurs and a 10-metre-long crocodile that was the final survivor of a protracted lineage of Jurassic marine crocodiles.
The fossil report additionally incorporates the oldest recognized marine turtles within the lineage of right now’s sea turtles in addition to the origins of a number of crustaceans that survive right now .
The knowledge within the fossil report helps us reconstruct historic meals internet interactions primarily based on what was current within the Japanese Pacific and the Western Tethys previous to their contact and what was current throughout their contact within the Paja Formation. Adjustments to those historic meals webs promise to make clear the environmental and ecological components concerned within the long-term sustainability of ecosystems.
(Hace Tiempo/C. Jaramillo and Guillermo Torres Carreño), Creator offered
Cautious inspection of fossils from this distinctive time and place affords a brand new window into what occurs when ecosystems collide. Up to now, we’re discovering this facilitates the evolution of monumental prime predators and several other evolutionary origins of recent lineages that might persist for thousands and thousands of years.
These outcomes present related knowledge for higher understanding of the implications of the Jurassic-Cretaceous extinction on marine animals and, in the end, of the arrival of right now’s marine ecosystems.