Scientists in Egypt have made the discovery of a four-legged whale, an ancestral species and a transitional form between land-dwelling mammals and modern, purely aquatic whales.
The newly discovered ancestral whale, called Phiomicetus anubis, is named partly after Anubis, the canine-headed Egyptian god associated with death and the afterlife. Found in the Fayum depression, it is in line with similar ancestral semi-aquatic fossils found in other continents.
Whale evolution is amply documented with a strong evidentiary basis in the fossil record. Evolving from aquatic artiodactyls, palaeontologists have been examining the ancestral species of modern whales – and the related cetaceans – for decades. Protocetids are semiaquatic whales that inhabited a niche midway between their semi-terrestrial predecessors and the ocean-going whales.
Possessing a raptor-like feeding style, they were fearsome predators. Phiomicetus anubis weighed an estimated 600 kilograms, and was three metres in length. The Phiomicetus is not the only ancestral quadrupedal whale fossil that has been found.
Back in 2019, scientists in Peru discovered the fossil of an ancient four-legged whale with hooves – adapted for a semi-aquatic lifestyle. Located in marine sediments off the coast of Peru, that finding, of a 42.6 million years old creature, shed light on the transition from land to sea by the ancestors of today’s largest mammals.
Fossils which are morphologically transitional from land mammals to modern, purely aquatic, whales are not without precedent. In 2010, National Geographic magazine reported that whales are descended from aquatic, hoofed ancestors. Indohyus, an amphibious ancestor of modern whales, had hooves with slender legs, and would take to water in the course of feeding and avoiding danger.
Indohyus, now extinct, lived 50 million years ago in what is now Southern Asia. It is an early member of the cetacean stem, related to whales and dolphins. While Indohyus had legs resembling a small deer, it also possessed the dentition of early modern whales. It lived life in both terrestrial and aquatic milieus, it possessed an involucrum, an ancient cetacean trait – a thickened piece of bone which helps whales to hear underwater.
Do palaeontologists and evolutionary biologists expect to find a transitional form of half-salamander and half-giraffe? Of course not. Creationist commentators make ridiculous claims, imputing them to evolution. They have no understanding of phyla and existing morphological similarities.
Back in 1985, when I was learning high school biology and geology, creationist Michael Denton made the following statement about a purported difficulty in evolutionary biology – a hyperbolic claim repeated in different forms over the years:
to postulate a large number of entirely extinct hypothetical species starting from a small, relatively unspecialized land mammal and leading successively through an otter-like state, seal-like stage, sirenian-like stage and finally to a putative organism which could serve as the ancestor of the modern whales. Even from the hypothetical whale ancestor stage we need to postulate many hypothetical primitive whales to bridge the not inconsiderable gaps which separate the modern filter feeders (baleen whales) and the toothed whales.Denton (1985) Evolution: A Theory in Crisis Adler & Adler Publishers:Chevy Chase, MD. p. 174
Be careful what you wish for – because the quadrupedal and semi-aquatic ancestral whale is precisely the finding that renders Denton’s observation completely irrelevant. Back in 2007, former child actor now creationist preacher Kirk Cameron, mocked evolution by presenting a fictional hybrid animal consisting of half duck-like features, and half-crocodile – a crocoduck.
Once again – be careful what you wish for; Kirk should make the acquaintance of Anatosuchus, a species among numerous examples of what can be reasonably described as a ‘crocoduck.’ The purpose of the current article is not an exercise in egotistical chest-thumping. Learning about evolutionary biology and geology in high school – a Catholic school – was a rewarding and enriching experience. The curriculum was set by the Australian Academy of Science.
Science education, and the public understanding of science, are crucial areas which impact public policy. In this age of the Covid-19 pandemic, it has become painfully obvious why more people should engage with scientists and achieve scientific literacy. Of course, no single individual can become a subject matter expert on every branch of science. However, we cannot afford to be indifferent to the developments of science – and not just because of the impact of technology.
Understanding new technology is important, but it is only one part of the full interplay between science and society. Science denialism is a serious hindrance to the public acceptance of policies based on scientific issues. Climate change denialism, while relatively new, is actually based on earlier denial of evolutionary biology, and anti-vaccination hostility for that matter. We have trained ourselves to be deniers – it is time to retrain our minds to accept evidence.