A formidable, 2-3-meter-long predator with a jaw twice as long as the skull and sharp teeth preyed on cephalopods or fish in the deep Devonian seas. We owe our knowledge about it to two Polish researchers, as well as a team of scientists from France, Switzerland, and Germany conducting parallel research.
The results of the joint study have just been published in the journal Royal Society Open Science.
It all started in 1957 when the outstanding Polish paleontologist Julian Kulczycki, the first researcher of vertebrates at the Department of Palaeozoology at the Polish Academy of Sciences, found strange, long bones in the Świętokrzyskie Mountains near Chęciny. He thought they were fish fin spines. He named the species of armored fish
“Alienacanthus malkowskii.” Kulczycki chose the second part of the Latin name of the animal to honor
Professor Stanisław Małkowski, an employee of the Polish Geological Institute and the
first director of the Earth Museum of the Polish Academy of Sciences.
Researchers from the Polish and foreign teams found out about their respective discoveries accidentally during one of the scientific conferences. From then on, they worked together on further research and description of Alienacanthus. They determined that this armored fish (Latin: Placodermi) was
2.5 to 3-meters-long,
had large eyes, and
a massive, about 80-cm-long and narrow head. Its lower jaw had two long spines with sharp, conical, backward-curved teeth. Scientists agreed that this Devonian armored fish would be named according to Julian Kulczycki’s wishes.
Modern-day equivalent of Alienacanthus
A modern-day fish similar to Alienacanthus is
halfbeak, a small herbivorous fish from the Indian Ocean that also has a very elongated lower jaw. However,
it belongs to a completely different group - it is a bony, ray-finned fish.
Researchers are not entirely sure what the fish used such elongated jaws for. They speculate that Alienacanthus could have used them to dig through the seabed in search of food. The sharp teeth on the edges indicate that
the long bones were used to scatter or wound victims. According to scientists, the bones could also have been a defensive weapon to deter other predators.
Several million years after the appearance of the species Alienacanthus malkowskii,
armored fish became extinct during one of the great extinctions.
“It seemed that we knew all there was to know about placoderms. We know about their viviparity, the structure of internal organs, and various life strategies. But
the fish we have discovered turns out to be unlike anything else known from the Devonian. Similar skeletal modifications appeared many years later and remain rare even in modern fauna,” Professor Szrek said.
The authors of the study emphasize that studying fossils helps to understand not only how the spine, teeth, fins, or limbs of the earliest vertebrates developed but also how they evolved and diversified over time.
