Acadagnostus facts for kids

Acadagnostus is a type of ancient sea creature called a trilobite. It lived during the Middle Cambrian period, which was about 505 to 497 million years ago. Scientists have found seven different kinds, or species, of Acadagnostus.

The most common species, A. acadicus, has been found all over the world. Its fossils have appeared in North America, Greenland, England, Europe, Central Asia, China, and Australia. This wide spread shows that Acadagnostus was a very successful creature in its time.

What Does the Name Acadagnostus Mean?

The names of the different Acadagnostus species often describe something about them. These names come from Latin or Ancient Greek words.

• ancisa: This Latin word means 'cut round'. It describes the rounded shape of the tail shield of this species.
• australis: This Latin word means 'southern'. This species was likely found in southern regions.
• certus: This Latin word means 'definite' or 'sure'.
• syrma: This Ancient Greek word means 'robe with a train'. It refers to the wide border on the tail shield, which looked like a long train.

What Did Acadagnostus Look Like?

Acadagnostus was a small trilobite. Like all trilobites in its group (Agnostida), its head shield (called a cephalon) and tail shield (called a pygidium) were about the same size and shape. This is known as being isopygous.

Acadagnostus had only two body segments in its middle section (called the thorax). Its head shield was round and did not have any spines. The edge of the head shield was narrow, but the groove next to it was wide.

The tail shield of Acadagnostus was somewhat square-shaped. It had a flat border that was sometimes wider at the back. There were also two small spines at the outer back corners. A large bump, called a median node, was present in the middle of the tail shield.

How is Acadagnostus Related to Other Trilobites?

Schematic showing the relationship between Acadagnostus (light green), other Peronopsid genera (darker green) and other families (other colors).

Scientists believe that Acadagnostus likely came from an ancestor similar to another trilobite called Peronopsis normata.

It is also thought that Acadagnostus later led to the development of Pseudoperonopsis. This makes Pseudoperonopsis one of the earliest members of the Diplagnostidae family of trilobites.