Zilchovaspis rugosa trilobite 46mm, an amazing little arthropod (formerly Odontochile) re-named trilobite. The arthropod has been worked out of a bedrock block, this matrix is the original fossil bedrock, the age of which is around 400 million years ago. The trilobite expired in the silts of that time which have hardened into solid limestone.Here the articulation is very interesting, showing the constituent parts of the carapace (exoskeleton), of the once living invertebrate.
A Zilchovaspis rugosa trilobite prepared in the fossil preparation laboratory using pneumatic tools and finished with an air abrasive micro sand-blaster. This Trilobite is a Devonian Arthropod, a sea bottom dweller. This genus is known for its large eyes, genal thoracic spines and terminal pygidium (tail) spine. The Trilobite has been prepared to expose the exoskeleton (fossilised carapace), while retaining prostrate stance on the original matrix (fossil limestone bed rock).
A brief trilobite history; The order or group of trilobites evolved during the Pre-Cambrian period approximately 550 million years ago, One of the most complex forms of early life, the trilobites reign lasted over 270 million years coming to an end around 250 million years ago in the time of the Permian period. Trilobite genus-types were diverse and globally extensive. The Trilobite was a member of the Proetida Order, Family of the Proetidae. Trilobites were complex animals, having the first compound eyes and segmented bodies which enabled them to enrolled, possibly for a defense posture. The name trilobite refers to the three part body shape, this is longitudinally referenced to the tri-lobed effect of the whole arthropod and not, as often is the case, mistaken for the three main and distinctive constituent parts of the carapace, the cephalon (head), the thorax (body) and the pygidium (tail).
Condition report: The trilobite has been prepared, cleaned and treated with air abrasion to a high standard. The carapace is exceptionally fine displaying lumps and bumps, all the pustules that make these arthropods so intriguing.The glabella (head), thoracic segments and pygidium (tail) are in very good order. A few stress lines can be seen at the pygidium spine and on each genal spine. Looking in plan at the specimen the left genal spine has suffered some minor damage and has been filled with a proprietary clear fixative, this treated to be of minimal detraction aesthetically, when a strong light is shone through the spine it becomes clear it has been treated in this way. Often if not always areas like this are very skilfully coloured or toned to disguise any work or repair. It is acceptable with fossil specimens that if 25% of the fossil has this type of work it is considered a fair specimen. As 99.99% of fossils are damaged by erosion in the beds, on extraction, or when prepared or cleaned, the amount of wear here to this little arthropod is a 'very good' on the scale of preservation.
We felt it advisable on this occasion and with this particular specimen to not affect the wear and in fact highlight it to give a very honest appearance to the otherwise beautifully well preserved trilobite. Allowing the next owner to carry out a colour treatment if they so wished.