Fossils of Australiaest. 2013
Otarion Trilobite
FA-0306 · tap to enlarge

aulacopleurid trilobite

Otarion sp.

Silurian427.4–419.2 Ma
Catalogue
FA-0306
Phylum
Arthropoda
Class
Trilobita
Order
Proetida
Family
Aulacopleuridae
Locality
Yass district, New South Wales
Unit
not recorded
Age
Late Silurian (Ludlow–Přídolí)
427.4–419.2 Ma
Reference
Wikipedia

A small trilobite with a strongly inflated glabella — the raised central lobe of the head — and a short, few-ribbed tail. Most specimens are only a centimetre or two long.

Aulacopleurids favoured quiet, muddy sea floors and are often found enrolled, curled up like a woodlouse in the defensive posture the animal adopted when disturbed.