It has only been a couple of weeks since worldwide excitement erupted over the discovery of a new human ancestor, but already South Africa has churned out yet another fascinating fossil find. A new genus and species of coelacanth has been unearthed from the Eastern Cape, representing the earliest specimens to have been found on the continent so far.
If you’re wondering what the heck a coelacanth is and why this is important, allow me to enlighten you. Coelacanths are among the oldest types of fish in the world, considered by some to be “living fossils.” These ancient, primitive fish, which dwell at depths of up to 700 meters (2,300 feet), were believed to have been wiped off the face of the Earth alongside the dinosaurs, some 65 million years ago. But rather unexpectedly, to say the least, a live coelacanth was caught by a fisherman back in 1938, followed by another in 1952.
These prehistoric fish have now been spotted many times, but it’s not just this remarkable disappearing act that has attracted so much scientific interest, and controversy. Among their bizarre concoction of features is a pair of curiously limb-like, or “lobed,” fins that protrude out of the body like legs. Unlike other fish, these move in an alternating pattern and even contain bones that resemble toes. It’s therefore believed by many that animals like these marked a critical point in the transition from sea to land, representing an important link between fish and land-living vertebrates.
It’s thought that coelacanths appeared around 420 million years ago, with several different species from this period (the Devonian) described from incomplete specimens found in various parts of the world, including Europe and Australia, but interestingly not Africa. This new discovery, dating back about 360 million years, is therefore important for our understanding of the early evolution of these bizarre creatures.
Named Serenicthys kowiensis, more than 30 complete specimens of this new species were discovered at Waterloo Farm, a Late Devonian fossil estuary near Grahamstown. Alongside being remarkably well-preserved, all of the specimens are thought to represent juveniles. According to the authors, this suggests that Serenichthys was using the sheltered estuarine environment as a nursery, much like many modern-day fish species. Prior to this find, the earliest example of such a coelacanth nursery came from 300 million-year-old specimens found in America. You can read more about the find in the Zoological Journal of the Linnean Society.
“This glimpse into the early life history of ancient coelacanths raises further questions about the life history of the modern coelacanth, Latimeria, which is known to bear live young, but whether they, too, are clustered in nurseries remains unknown,” lead researcher Professor Michael Coates from the University of Chicago said in a statement from the University of the Witwatersrand.
Interestingly, S. kowiensis was found just 100 kilometers (62 miles) from the area that the first live coelacanth was caught back in 1938. And from the researchers’ analyses, they believe that, of those Devonian coelacanths discovered so far, this particular species displays the most similarities to those found today.