Remains of trilobites have been found all over the world. The sheer volume of species and subspecies of trilobites are a rarity for most creatures during this period. Trilobites are considered one of the most fascinating early life forms on the planet for a variety of reasons. And while there are distinct similarities in all trilobite fossils, they are found in many variations of size – and weight.
Trilobites varied in size and in some of their features. Because they survived for approximately 300 million years, it is easy to understand why there would be variations in trilobite sizes found across the globe. Geologists have defined between 20,000 and 50,000 species of trilobites. Some are less than 3 millimeters (.12 inches) in length, while others have been found to exceed 30 centimeters (12 inches) in length. These extremes are generally considered the typical range of trilobite species.
The smallest known trilobite fossil specimens come from the species Acanthopleurella stipulae. These average just 1.5 millimeters in length (.06 inches). The largest trilobite fossil ever discovered is from the Isotelus rex species. It was found in Canada's Hudson Bay in 1998 and is a whopping 72 centimeters (28 inches) in length!
If you don't have room for one of these in your trilobite display case, don't worry. The average size of a trilobite fossil ranges from 3 to 10 centimeters (1.2 to 3.9 inches).
Since trilobite species can vary so much in size, the weights of these fossilized remains differ as well. While their size often determines actual fossil weights, many trilobite fossils are embedded and cannot be separated easily from the rock. The weight variations of these entire inseparable pieces can be extreme, though the total heft isn't reflective of the actual weight of the trilobite fossils themselves, which tend to be much lighter.
Most trilobite fossils, in and of themselvesm are less than 6 inches in length and weigh less than 2 pounds. Many are lighter and many are actually heavier. The largest known trilobite fossils come from a group known as Paradoxides harlani. These trilobites lived during the middle Cambrian period. On average they grew to more than 45 centimeters (18 inches). Their average weight was about 4.5 kilograms, or 10 pounds.
When it comes to fossilized remains of trilobites that are on the market, weights can range from a few ounces to 12 pounds or more. As mentioned, much of the weight depends on whether the creature is embedded in a rock bed. Beyond simply the size, these fossilized remains can be found all over the world and are discovered in many different locations. Water conditions, plus rock types and composition, make trilobite fossil weights vary quite a bit.
In some cases, several dozen fossilized trilobites have been discovered together in rock beds. These have been cut out of the rock and are considered a fossilized group. They are generally marked for museum use and can even include different species.
One fossilized group of 20 Basseiarges trilobites has been discovered with several other complete Austerops trilobites in one rock bed. Discovered in Morocco, this piece was placed on the market – cost, just under $5,000. In cases like these, while the fossils themselves are not weighty, the fossil group and the rock together is substantial in weight. These fossilized remains in rock beds have weighed over a hundred pounds.
When buying (or lifting out of the ground, you lucky archeologist!) trilobite fossils, be prepared to deal with some significant weight. That means paying for the extra shipping costs. It's part of the reality of buying and collecting trilobite fossils, but it's a minor quibble when obtaining fossilized creatures that are so interesting.
https://www.britannica.com/animal/trilobite
https://en.wikipedia.org/wiki/Trilobite
https://www.amnh.org/research/paleontology/collections/fossil-invertebrate-collection/trilobite-website/the-trilobite-files/the-largest-trilobites
Outstanding Utaspis marjumensis Fossil Trilobite Marjum Formation Cambrian Utah
Seller: mnmark
Large Dramatic Olenoides vali Trilobite Rarity Drum Mtns. - Utah!!
Seller: richiesrocks
Teresellus goldfieldensis Trilobite Seabed Plate, Poleta Fm. Goldfield, Nevada
Seller: fossilsinc
KILLER RARE BOTHRIOLEPIS CANADENSIS ARMORED FISH FOSSIL, DEVONIAN - PRIMITIVE!
Seller: extinctions
Unprepared Olenellus chiefensis trilobite, Lower Cambrian, Nevada
Seller: fossilsinc
Fossilized Reedops Deckeri
Seller: chrisoneblue
