Gravicalymene coppinsensis belongs to one of the most popular fossil groups to have appeared in the fossil record, trilobites! Trilobites are an extinct group of marine arthropods (same group as spiders, scorpions, crabs and horseshoe crabs) that first appeared in the Cambrian period (540 Million of years ago) and went extinct at the end of the Permian period (250 Million years ago). Trilobites form one of the earliest-known groups of arthropods. Arthropods are invertebrates with jointed legs and include spiders, scorpions, crabs and insects. The name trilobite comes from their three lobed exoskeleton.
There are over 20,000 species of described trilobites recorded, with more every year. They make an excellent addition to any amateur or professional collection. Since trilobites are found all over the world, limited to a particular geological time frame, are easily recognisable and preserve very well for a fossil, they are extremely useful for relatively dating the age of a rock and provide a rough idea on what geological time period scientists are looking at when they first discover the rock.
Gravicalymene coppinsensis was discovered at Coppins Crossing in the ACT and was named accordingly. Normally, these guys are found as fragments because they moult their skin and have articulated joints like spiders or scorpions do, however this particular specimen is a near complete sample, which is very rare to find. Gravicalymene is larger and more robust than Batocara, however they both lived a similar lifestyle. Unfortunately, the site where Gravicalymene was first discovered is no longer accessible because it has since been covered by the Lower Molonglo wastewater treatment infrastructure.
Interestingly, this species of trilobite has recently undergone taxonomic revision by scientists. When it first described in 1980, it was named Apocalymene coppinsensis, however later in that year, it was allocated into a different genus called, Sthenocalymene coppinsensis. It has remained in that particular genus until 2020, where a scientist from the Australian Museum assigned to a different genus and has been named as Gravicalymene coppinsensis.