Greetings from the first ruler of the seas

Director´s view

Miroslav Bobek  |  25. 03. 2019

Similar to a dragon, it hovered in the Cambrian seas by waving its body. It had large compound eyes, to help it search for trilobites, long appendages, a kind of claw, protruding from the front of the body, a circular, downward-pointing mouth with lamellar plates, for crushing prey, and a series of flaps along the body that, along with its fanned tail, provided it with motion. The most dangerous predator of its time. Anomalocaris.

Illustration: Pavel Procházka Illustration: Pavel Procházka

The name of this “first ruler of the seas”, perhaps related to today's arthropods, although it bears little resemblance to any contemporary animal, comes from the late 19th century and means “anomalous shrimp”. A fossil of its appendage was found in Canada and thought to be a strange, extinct shrimp. Fossils of its mouth, with lamellar “teeth”, were later discovered, and palaeontologists described it as a Cambrian jellyfish and holothurian or “sea cucumber”. It took a long time before it was possible to piece together these seemingly unrelated animals into the bizarre trilobite hunter - anomalocaris.

It was not only the most dangerous, but also the largest animal at the time. Anomalocaris could have measured as much as a metre and, according to some sources, even well over a metre. Hurdia was very similar, although smaller. Its remains have also been found in our country, near Příbram.

So that finally brings me round to the “greeting” from anomalocaris - or maybe hurdia - that you will soon be able to see at Prague Zoo. In 2005, a coprolite (fossilised excrement) that most likely came from one of these creatures was found near Příbram. It contains the remains of trilobites, which anomalocaris and hurdia crushed with the lamellar “teeth” of their circular mouths, leaving typical W-shaped bite-marks on them. This unique, half-billion-year-old fossil will be part of a permanent exhibition of coprolites and droppings, which we will be launching in Prague Zoo at the end of the week. Enjoy!

Miroslav Bobek