Following the Cretaceous Mass Extinction, ancient penguin relatives rapidly diversified
Mark P. Witton/Science Photo Library
Four newly discovered fossil species in New Zealand demonstrate the significant diversity of early penguins, characterized by their long, dagger-like beaks for catching prey.
The latest findings provide “an unexpected insight into the early evolution of penguins,” states Gerald Mayle at the Senckenberg Research Institute in Germany.
The fossils were unearthed from the Waipara Greensand Formation in Canterbury, New Zealand, a region recognized for flourishing after the mass extinction that eradicated non-avian dinosaurs, preserving some of the early avian species that diversified.
“A notable aspect of ancient New Zealand is the lack of terrestrial predators, which enabled early penguins to lose their ability to fly,” explains Mayle. This absence of predators might also clarify why certain early penguins reached sizes as large as humans, he remarks.
In total, Mayr and colleagues detailed four new species, showcasing a remarkable variety of shapes and sizes. Many fossils reveal previously unknown skeletal characteristics; one specimen boasted an exceptionally long back toe, along with an incredibly intact skull and beak.
“Fossils with beaks that provide insight into avian diets are exceedingly rare among penguins from earlier epochs [23 million years ago],” says Tatsuro Ando, who was not part of the study at the Japanese Paleontology Museum.
Present-day penguins feature varied beak shapes tailored to their specific prey, which can include krill and small fish, as well as invertebrates like squid, Ando explains. While these beaks can be short, thick, or curved, they do not compare to those seen in early penguins.
“It appears that ancient penguins utilized their long beaks to grasp their prey,” says Mayle. After impaling the fish, they likely surfaced to toss it into the air and catch it, he adds.
Over a span of approximately 20 million years, penguins evolved to lose their elongated, slender beaks. This change was likely an adaptation to prolonged underwater periods. As they transitioned to a more aquatic lifestyle, their feeding strategies and beak structures also evolved.
The newfound fossils underscore the significance of New Zealand as a “cradle of penguin evolution,” remarked Mayle, indicating that the earliest penguins diversified and spread globally to regions including New Zealand, Antarctica, South Africa, and South America.
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Source: www.newscientist.com
