Discovery of an extinct marine reptile shaped like a swordfish

A team of international researchers from Canada, Colombia and Germany have discovered a new marine reptile. The specimen, a surprisingly preserved meter-long skull, is one of the last surviving ichthyosaurs – ancient animals that eerily resemble a living swordfish.

“This animal developed a unique dentition that allowed it to eat large prey,” explains Hans Larsson, director of the Redpath Museum at McGill University. “While other ichthyosaurs had small, equal-sized teeth to feed on small prey, this new species altered the size and spacing of its teeth to build an arsenal of teeth for sending large prey, such as large fish and other marine reptiles. “

“We decided to name him Kyhytysuka which translates to “one who cuts with something sharp” in a language indigenous to the region of central Colombia where the fossil was found, to honor the ancient Muisca culture that had existed there for millennia, ” explains Dirley Cortés, a graduate student supervising Hans Larsson and Carlos Jaramillo of the Smithsonian Tropical Research Institute.

Reconstructions of the life of Kyhytysuka sachicarum from the Lower Cretaceous of Colombia. Credit: Dirley Cortés

The big picture of ichthyosaur evolution is clarified with this new species, the researchers say. “We compared this animal to other ichthyosaurs from the Jurassic and Cretaceous and were able to define a new type of ichthyosaur,” explains Erin Maxwell of the National Museum of Natural History in Stuttgart (former graduate student of Hans Larsson’s laboratory at McGill). “It turns the ichthyosaurs evolutionary tree upside down and allows us to test new ideas about how they evolved.”

Dirley Cortés working with Kyhytysuka’s skull. Credit: Dirley Cortés

According to the researchers, this species arose from an important transition period during the Lower Cretaceous. At this time, Earth was emerging from a relatively cold period, sea level was rising, and the Pangea supercontinent was dividing into northern and southern landmasses. There was also a global extinction event at the end of the Jurassic which altered marine and terrestrial ecosystems. “Many classic Jurassic marine ecosystems of deep-water-feeding ichthyosaurs, short-necked plesiosaurs, and sea-adapted crocodiles have been replaced by new lineages of long-necked plesiosaurs, sea turtles, large lizards. sailors called mosasaurs, and now this ichthyosaur monster, ”says Dirley Cortés.

Kyhytysuka skeleton compared to a human for the scale. Known bones are white. Credit: Dirley Cortés

“We are discovering many new species in the rocks from which this new ichthyosaur originated. We are testing the idea that this region and time in Colombia was a former biodiversity hotspot and are using fossils to better understand the evolution of marine ecosystems during this period of transition, ”she adds. As next steps, researchers continue to explore the wealth of new fossils preserved in the Centro de Investigaciones Paleontológicas of Villa de Leyva in Colombia. “This is where I grew up,” Cortés says, “and it’s so rewarding to be able to do research here too.”

Kyhytysuka dinosaur animation video

3D animation of Kyhytysuka. Credit: Dirley Cortés

About McGill University

Founded in Montreal, Quebec, in 1821, McGill University is the best medical doctoral university in Canada. McGill is consistently ranked among the top universities, both nationally and internationally. It is a world-renowned higher education institution with research activities spanning three campuses, 11 faculties, 13 vocational schools, 300 study programs and over 40,000 students, including over 10,200 graduate students. McGill attracts students from over 150 countries around the world, with its 12,800 international students representing 31% of the student body. More than half of McGill students report having a mother tongue other than English, including around 19% of our students who say French is their mother tongue.

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