Trilobites (pronounced "TRY-loh-bee-ts" or "TRIL-uh-bee-ts") are ancient sea creatures that are no longer alive. They belong to the class Trilobita and were among the first arthropods to appear in the fossil record. Trilobites lived in the ocean for nearly 270 million years and more than 22,000 different types have been found as fossils. Their hard shells, made of a mineral called calcite, made them easy to find as fossils. Scientists study trilobite fossils to learn about Earth's history, including how life evolved and how continents moved over time. Trilobites are part of a group called Artiopoda, which includes other creatures with similar body shapes but softer bodies. Scientists are still unsure how Artiopoda is related to other arthropods.
Trilobites filled many different roles in the ocean. Some crawled along the seafloor as predators, scavengers, or filter feeders, while others swam and ate plankton. A few even moved onto land. Most types of life seen in modern sea creatures are also found in trilobites, except for parasitism, which is still debated by scientists. Some trilobites, like those in the Olenidae family, may have lived with bacteria that helped them get food. The largest trilobites were over 70 centimeters (28 inches) long and weighed up to 4.5 kilograms (9.9 pounds).
The first trilobites appeared in the fossil record about 521 million years ago, marking the start of the Atdabanian/Cambrian Stage 3 time period. Soon after, trilobites became widespread and diverse, reaching their peak during the late Cambrian and Ordovician periods. They remained common during the Silurian and early Devonian periods. However, their numbers dropped sharply during the mid- to late Devonian due to several major extinction events, such as the Taghanic extinction, the Late Devonian mass extinction, and the Hangenberg extinction. These events nearly wiped out all trilobites, leaving only one group, the Proetida, to survive. Their numbers slowly increased during the Early Carboniferous period but stayed low during the late Carboniferous and Permian periods. Trilobites disappeared completely during the end-Permian mass extinction, which happened about 251.9 million years ago. By that time, only a few species remained.
Evolution
Trilobites are part of a group called Artiopoda, which includes extinct arthropods that look similar to trilobites. However, only trilobites had hard, mineralized outer coverings. Because of this, other artiopodans are usually found only in rare, well-preserved fossil deposits, mostly from the Cambrian period.
Scientists are still unsure how artiopods are related to other arthropods. Some believe they are closely linked to chelicerates, such as horseshoe crabs and spiders, as part of a group called Arachnomorpha. Others think they are more closely related to Mandibulata, which includes insects, crustaceans, and millipedes, as part of a group called Antennulata.
The earliest trilobites in the fossil record are redlichiids and ptychopariid bigotinids, which lived about 520 million years ago. Some of the oldest known trilobite fossils include species like Profallotaspis jakutensis (Siberia), Fritzaspis (western US), Hupetina antiqua (Morocco), and Serrania gordaensis (Spain). These trilobites appeared at the same time in regions like Laurentia, Siberia, and West Gondwana.
Olenellina trilobites lack facial sutures, which are lines on the head. Scientists think this feature was the original state for trilobites. The earliest trilobite with facial sutures, Lemdadella, appeared around the same time as the earliest Olenellina, suggesting trilobites may have existed before the Atdabanian period, but without leaving fossils. Other groups, like Agnostina and some Phacopina, later lost their facial sutures. Another sign that Olenellina are the earliest trilobites is that no early stages of their development (protaspid stages) have been found, possibly because these stages were not calcified.
In 2024, researchers discovered soft tissues, including the labrum, in trilobite fossils from Morocco that are 478 million years old. These fossils, found in Cambrian Stage 4 deposits, show new details about trilobite anatomy. Scientists believe the excellent preservation was caused by the trilobites dying quickly after an underwater pyroclastic flow event.
Over time, trilobites diversified into many different forms. As a long-lasting group, their history includes several extinction events where some species died out, and others adapted to fill new roles. Trilobites remained diverse during the Cambrian and Ordovician periods but began to decline in the Devonian, ending with their extinction at the end of the Permian period.
Important evolutionary changes from early trilobites, like Eoredlichia, include the development of new eye types, better mechanisms for curling and moving, larger pygidiums (from small to equal in size), and extreme spikiness in some groups. Other changes involved narrower thoraxes and varying numbers of body segments. The head (cephalon) also changed, with differences in the glabella’s size, eye position, and facial sutures. Some features, like eye reduction or small size, appeared independently in different groups.
Effacement, the loss of surface details on the head, pygidium, or body segments, is a common trend. This is seen in groups like Agnostida and Asaphida. Scientists think effacement may indicate a burrowing or open-ocean lifestyle. However, this loss of detail makes it harder for scientists to classify trilobites and understand their relationships.
Although some early theories suggested trilobites existed before the Cambrian, this is no longer supported. Instead, trilobites likely appeared just before their fossils were found in the lower Cambrian. Soon after, they diversified into major groups like Redlichiida, Ptychopariida, Agnostida, and Corynexochida. A major crisis in the Middle Cambrian led surviving groups to develop thicker, stronger outer coverings for protection. The Late Cambrian marked the peak of trilobite diversity, but the end-Cambrian mass extinction wiped out many species, including most Redlichiida and Late Cambrian trilobites.
Notable trilobite genera from the Cambrian include:
The Early Ordovician saw the rise of many new marine life groups, such as brachiopods, bryozoans, and bivalves. While trilobite diversity peaked in the Cambrian, they still played a role in the Ordovician radiation, with new groups like Phacopida and Trinucleioidea emerging. These groups likely had Cambrian ancestors, but their rapid evolution made them hard to detect. The Ordovician mass extinction reduced some trilobite groups, like Telephinidae and Agnostida, but many survived into the Silurian. The Ordovician was the last major period of trilobite diversification, with few new body plans appearing afterward.
Some trilobite genera from the Ordovician include:
Most Early Silurian trilobite families were part of the Late Ordovician group. While few Early Ordovician species survived the Ordovician extinction, 74% of Late Ordovician trilobites lived on. Silurian and Devonian trilobites resembled Ordovician ones, with groups like Lichida and Phacopida dominating. Silurian trilobite diversity was high during the Llandovery and Wenlock periods but dropped sharply at the end of the Silurian. Diversity increased again in the Early Devonian, reaching 180 genera during the Emsian stage.
The Middle to Late Devonian was a turning point for trilobites. The Taghanic event during the Givetian stage sharply reduced their diversity, especially in shallow waters.
Fossil distribution
Trilobites were mostly sea creatures, as their fossil remains are always found in rocks that also contain fossils of other saltwater animals, such as brachiopods, crinoids, and corals. Some evidence suggests trilobites may have briefly moved onto land. In the ancient ocean environment, trilobites lived in many different water depths, from very shallow to extremely deep. Like brachiopods, crinoids, and corals, trilobites are found on all modern continents and lived in every ancient ocean where Paleozoic fossils have been discovered. Fossil remains of trilobites can include their entire body, parts of their exoskeleton (which they shed during a process called ecdysis), or the tracks they left on the seafloor, which are preserved as trace fossils.
Three main types of trace fossils are linked to trilobites: Rusophycus, Cruziana, and Diplichnites. These fossils show the activities of trilobites on the seafloor. Rusophycus are marks left when trilobites rested or moved little, possibly for protection or hunting. Cruziana are furrows in sediment, likely made by trilobites as they fed on the seafloor. Diplichnites are tracks left by trilobites walking on the sediment. Scientists must be careful, as similar trace fossils in freshwater or later geological layers may not be from trilobites.
Trilobite fossils are found worldwide, with thousands of known species. Because they appeared quickly in Earth's history and shed their exoskeletons like other arthropods, trilobites are useful as index fossils, helping geologists determine the age of the rocks they are found in. They were among the first fossils studied widely, and new species are still being discovered today.
In the United States, one of the best public trilobite collections is in Hamburg, New York, at a site called Penn Dixie. This quarry stopped mining in the 1960s, and trilobites were discovered there in the 1970s by a rock collector named Dan Cooper. His work sparked interest in the site. The fossils are from the Givetian period (387.2–382.7 million years ago), when the area was near the equator and covered by water. The town of Hamburg purchased the land in partnership with a local natural history society to protect it from development. In 1994, the site became Penn Dixie Fossil Park & Nature Reserve and opened to the public. The two most commonly found trilobites there are Eldredgeops rana and Greenops.
In the United Kingdom, a famous trilobite site is Wren’s Nest in Dudley, West Midlands, where Calymene blumenbachii is found in the Silurian Wenlock Group. This trilobite is on the town’s coat of arms and was once called the Dudley Bug or Dudley Locust by workers in nearby limestone quarries. Another site is Llandrindod Wells in Powys, Wales. The Elrathia kingi trilobite is found in large numbers in the Cambrian Wheeler Shale in Utah, USA.
Well-preserved trilobite fossils, including soft body parts like legs, gills, and antennae, have been found in several locations. These include the Cambrian Burgess Shale and similar sites in British Columbia, Canada; the Ordovician Walcott–Rust quarry and Beecher’s Trilobite Bed in New York, USA; the Lower Cambrian Maotianshan Shales in China; the Devonian Hunsrück Slates in Germany; and, less commonly, in Utah, Ontario, and Manuels River, Newfoundland and Labrador.
In Morocco, trilobites are also well-preserved, often buried alive in mudslides. This has led to an industry focused on recovering and restoring these fossils, which has raised concerns about restoration practices. These fossils show a wide variety of eye shapes and body structures, similar to how bodies were preserved in Pompeii.
The French paleontologist Joachim Barrande (1799–1883) conducted a major study of trilobites in the Cambrian, Ordovician, and Silurian periods in Bohemia. He published the first volume of Système silurien du centre de la Bohême in 1852.
Importance
Niles Eldredge's research on Paleozoic trilobites near the Welsh-English borders was important for helping scientists develop and test the idea of punctuated equilibrium, a theory about how evolution happens.
Finding differences between 'Atlantic' and 'Pacific' trilobite groups in North America and Europe showed that the Iapetus Ocean had closed, forming the Iapetus suture. This discovery supported the theory that continents move over time.
Trilobites are helpful for scientists studying how quickly new species appeared during the Cambrian explosion. They are the most varied group of animals found in early Cambrian fossils.
Trilobites are useful for identifying rock layers from the Cambrian period. For example, trilobites with certain body parts, like an alimentary prosopon and a micropygium, are signs of Early Cambrian rock layers. Much of what scientists know about Cambrian rock layers comes from studying trilobite fossils.
Trilobites are the official fossils of Ohio (Isotelus), Wisconsin (Calymene celebra), and Pennsylvania (Phacops rana).
Taxonomy
The 10 most commonly recognized trilobite orders are Agnostida, Redlichiida, Corynexochida, Lichida, Odontopleurida, Phacopida, Proetida, Asaphida, Harpetida, and Ptychopariida. In 2020, an 11th order, Trinucleida, was proposed to be moved from the asaphid superfamily Trinucleioidea. Sometimes the Nektaspida are considered trilobites, but these lack a hard outer shell and eyes. Some scholars suggest that the order Agnostida may have multiple origins, with the suborder Agnostina representing non-trilobite arthropods unrelated to the suborder Eodiscina. Under this idea, Eodiscina would be classified as a new order, Eodiscida.
Over 22,000 trilobite species have been described.
Although trilobites have a large fossil record with thousands of known genera found worldwide, their classification and evolutionary relationships remain uncertain. Except for the orders Phacopida and Lichida (which first appear in the early Ordovician), nine of the 11 trilobite orders existed before the end of the Cambrian period. Most scientists believe the order Redlichiida, specifically its suborder Redlichiina, contains the ancestor of all other trilobite orders, except possibly Agnostina. Many studies suggest that Redlichiina gave rise to the orders Corynexochida and Ptychopariida during the Lower Cambrian, while Lichida may have evolved from Redlichiida or Corynexochida in the Middle Cambrian. The order Ptychopariida is the most difficult to classify. In the 1959 Treatise on Invertebrate Paleontology, what are now members of Ptychopariida, Asaphida, Proetida, and Harpetida were grouped as Ptychopariida. In 1990, a subclass called Librostoma was created to include these orders, based on their shared feature of a natant (unattached) hypostome. The most recently recognized trilobite order, Harpetida, was established in 2002. The origin of the Phacopida order is still unclear.
Morphology
When trilobites are found in the fossil record, only their hard outer covering, called the exoskeleton, is usually preserved. In most cases, the exoskeleton is incomplete. However, in a few special locations (called Lagerstätten), soft body parts like legs, gills, muscles, and the digestive system are also preserved. These sites may also show details of other structures, such as the fine parts of the eyes. Of the 20,000 known trilobite species, only 38 have fossils that show preserved appendages.
Trilobites ranged in size from very small, less than 1 millimeter (0.039 inches) long, to very large, over 70 centimeters (28 inches) long. The average size was between 3–10 centimeters (1.2–3.9 inches). The smallest known species, Acanthopleurella stipulae, was about 1.5 millimeters (0.059 inches) long. The largest known trilobite, Isotelus rex, was 72 centimeters (28 inches) long. It was discovered in 1998 by scientists in Canada in rocks from the Ordovician period near Hudson Bay. Another trilobite, Hungioides bohemicus, found in Portugal in 2009, was estimated to have been 86.5 centimeters (34.1 inches) long when complete.
Only the top part of the trilobite’s exoskeleton, called the dorsal part, is made of minerals like calcite and calcium phosphate. This part is covered in a framework of chitin and curls around the bottom edge to form a small fringe called the "doublure." The appendages and soft underside were not made of minerals. The body was divided into three main sections: the cephalon (head), thorax (body), and pygidium (tail).
Trilobites are a large group with about 5,000 genera, so their body shapes and features can be complex. Despite this, they have some unique traits that set them apart from other arthropods. These include a generally oval-shaped, chitinous exoskeleton divided into three distinct lobes (which gives the group its name), a large head shield (cephalon) that connects to the thorax, and a tail shield (pygidium) formed from the fused segments at the end of the thorax. Differences between trilobite species are often described based on the size, shape, and features of the head.
During molting, the exoskeleton usually splits between the head and body, which is why many trilobite fossils are missing either the head or the body. On the head, lines called facial sutures helped the trilobite shed its old exoskeleton. Like lobsters and crabs, trilobites likely grew between the time they shed their old exoskeleton and when the new one hardened.
The head section (cephalon) of a trilobite is highly variable in shape. A dome-like structure called the glabella sat beneath the head and held the "crop" or "stomach." The exoskeleton usually has few features on the underside, but the head often shows marks where muscles were attached. A small, rigid plate called the hypostome, similar to the ventral plate in other arthropods, was sometimes present. The mouth and stomach were located on the hypostome, with the mouth facing backward.
The shape and position of the hypostome can vary. It may be supported by a soft membrane, fused to the front edge of the doublure with a shape similar to the glabella, or fused with a shape different from the glabella. Differences in the size of the glabella, the edges of the head, and the hypostome are linked to different lifestyles, diets, and ecological roles.
In some trilobites, the front and sides of the head are greatly expanded. In others, a bulge near the front of the head suggests a brood pouch. Complex compound eyes are also a notable feature of the head.
Facial sutures are the natural lines on the head that helped trilobites shed their old exoskeleton during molting. All species in the suborder Olenellina, which went extinct at the end of the Early Cambrian period (like Fallotaspis, Nevadia, Judomia, and Olenellus), lacked facial sutures. These trilobites are thought to be the earliest ancestors of later trilobites because they predated the evolution of facial sutures.
Some trilobites that evolved later also lost facial sutures. The type of sutures found in different species is used to classify and understand their evolutionary relationships.
The top surface of the head (cephalon) can be divided into two parts: the cranidium and the librigena ("free cheeks"). The cranidium includes the glabella (the central lobe of the head) and the fixigena ("fixed cheeks"). The facial sutures are located at the front edge, where the cranidium meets the librigena.
On the top of the head, facial sutures can be divided into five main types based on where they end in relation to the genal angle (the point where the sides and
Soft body parts
Only about 21 species have been found with preserved soft body parts, so some features, such as the posterior antenniform cerci found only in Olenoides serratus, remain hard to understand in the broader context.
Trilobites had one pair of preoral antennae and limbs that were not clearly divided into different types (four pairs on the head, one pair per thoracic segment, and some on the pygidium). Each walking leg had six or seven segments, similar to those of other early arthropods. These legs were attached to the coxa, which also had a feather-like exopodite, or gill branch, used for breathing and, in some species, swimming. A 2021 study found that the upper limb branch of trilobites functioned as a "well-developed gill" that provided oxygen to the blood, similar to the book gill in modern horseshoe crabs (Limulus). In Olenoides, the connection between the leg and body was distinct from the exopods of Chelicerata or Crustacea. The inside of the coxa (or gnathobase) had spines, likely used to handle prey. The last part of the exopodite often had claws or spines. Many hairs on the legs suggest adaptations for feeding (like the gnathobases) or for sensing movement while walking.
The mouth of trilobites was toothless and located on the back edge of the hypostome (facing backward), in front of the legs attached to the head. The mouth connected to the stomach through a small esophagus, which was located below the glabella and in front of the mouth. The "intestine" extended backward from the stomach to the pygidium. Limbs on the head were thought to help move food into the mouth, possibly cutting food on the hypostome and/or gnathobases first. Recent 3D imaging using propagation phase-contrast synchrotron microtomography (PPC-SRμCT) of a Bohemolichas incola specimen showed many undigestible pieces of Conchoprimitia osekensis (a small, extinct ostracod) in its digestive tract.
These fragments suggest B. incola crushed shells to eat them (durophagous predation). Since the shells were not identified by species but by their strength and size, B. incola likely ate whatever was available, similar to scavengers. The presence of shell fragments also shows how B. incola removed little nutrition from these shells, leaving behind remains. These findings support the idea that early trilobites may have had glands that produced enzymes to aid digestion.
While there is clear evidence for the mouth, stomach, and digestive tract (as described above), the heart, brain, and liver are only suggested (even though many reconstructions show them) with little direct proof.
Although rarely preserved, long muscles ran from the head to the middle of the pygidium, attaching to the axial rings to allow enrollment. Separate muscles on the legs pulled them aside during enrollment.
Sensory organs
Many trilobites had complex eyes and a pair of antennae. Some trilobites were blind, likely because they lived too deep in the ocean for light to reach them. This led to secondary blindness in this group of trilobites. Other trilobites, such as Phacops rana and Erbenochile erbeni, had large eyes that helped them see in bright, predator-filled waters.
The antennae of most trilobites were flexible, allowing them to be pulled back when the trilobite curled into a ball for protection. One species, Olenoides serratus, had antenna-like structures called cerci that extended from the back of its body.
Even the earliest trilobites had complex, compound eyes made of calcite, a type of mineral found in all trilobite eyes. This suggests that eyes in arthropods and possibly other animals may have evolved before the Cambrian period. Improved eyesight in both predators and prey during the Cambrian period is thought to have driven the rapid development of new life forms, known as the Cambrian explosion.
Trilobite eyes were usually compound, with each lens shaped like an elongated prism. The number of lenses varied: some trilobites had only one lens, while others had thousands in a single eye. In compound eyes, lenses were often arranged in a hexagonal pattern. The fossil record of trilobite eyes is well-preserved, allowing scientists to study their evolution over time, even though soft internal parts rarely survive.
The lenses of trilobite eyes were made of calcite (calcium carbonate, CaCO₃). Some trilobites used clear calcite crystals to form each lens. However, rigid calcite lenses could not change focus like the soft lenses in human eyes. In some trilobites, calcite formed a special double-layered structure, which improved depth perception and reduced optical flaws, as discovered by scientists René Descartes and Christiaan Huygens in the 17th century. A modern animal with similar lenses is the brittle star Ophiocoma wendtii.
In other trilobites, the Huygens interface was missing, and instead, a gradient-index lens was used, where the lens’s refractive power changed toward the center.
Some phacopid trilobites had sensory structures beneath their lenses, which included groups of sensory cells around a rhadomeric structure. These resemble similar structures in the eyes of modern arthropods, such as horseshoe crabs (Limulus).
Secondary blindness was common in long-lived trilobite groups, such as the Agnostida and Trinucleioidea. In groups like the Proetida and Phacopina from western Europe and the Tropidocoryphinae from France, studies show a trend of eye size reduction over time, eventually leading to blindness.
Other trilobite features, such as "macula" — thin areas on the underside of the hypostome — are thought to have acted as simple "ventral eyes" to detect light or help with navigation when swimming upside down.
Some types of prosopon, or structures on the trilobite’s head, may have acted as sensory tools to detect chemical or vibrational signals. For example, large pitted fringes on the cephalon of Harpetida and Trinucleoidea may have functioned as a "compound ear," especially since these species often had small or no eyes.
Development
Trilobites grew through a series of growth stages called instars. During the anamorphic phase of development, existing body parts grew larger, and new segments formed in a special area near the end of the body. This was followed by the epimorphic phase, where the trilobite continued to grow and shed its exoskeleton, but no new segments were added to the body. The combination of these two growth phases is called the hemianamorphic mode, which is common in many living arthropods.
Trilobites had a unique way of forming connections between body segments. These changes in how segments connected led to the three main stages of their life cycle, which are not easily compared to the life cycles of other arthropods. Growth and changes in shape occurred when trilobites were soft-bodied, right after shedding their old exoskeleton and before the new one hardened.
Trilobite larvae are known from the Cambrian period to the Carboniferous period and are found in all sub-orders. Larvae from closely related species look more similar to each other than those from distant relatives, making them useful for studying how trilobites are related to one another.
Although no fossils show direct evidence, trilobites are believed to have reproduced sexually and laid eggs. Some species may have carried eggs or larvae in a special pouch near the front of the body, especially in difficult environments. The size and shape of the first hardened stage vary between trilobite groups, suggesting some species developed more inside the egg than others. Early stages before the exoskeleton hardened may have existed, but this is not certain.
The earliest known post-embryonic stage of trilobites is called the "protaspid" stage, which occurs during the anamorphic phase. This stage starts with a head and tail that are not yet distinguishable and ends with a line separating the head and tail. New segments form at the back of the tail, but all segments remain joined together.
The "meraspid" stage, also part of the anamorphic phase, is marked by the formation of a joint between the head and the fused body segments. Before this stage, the trilobite had a head and a fused body plate. During the meraspid stage, new segments form near the back of the tail, and joints develop at the front of the tail, allowing segments to move freely in the body. Segments usually grow one at a time during each moult, though some species added two segments at once or one every other moult. Growth during this stage was significant, increasing the trilobite’s size by up to 30%–40%.
The "holaspid" stage, part of the epimorphic phase, begins when the trilobite reaches a stable number of body segments. Moulting continued during this stage, but the number of body segments remained the same. Some trilobites may have kept growing and moulting their entire lives, though at a slower rate once they matured.
Some trilobites underwent a major change in body shape at a specific growth stage, called "trilobite metamorphosis." This change involved losing or gaining features that reflected a shift in how the trilobite lived. Changes in lifestyle during development affected how trilobites survived and spread. For example, trilobites that spent their entire early life in the ocean (planktonic) and later lived on the seafloor (benthic) did not survive the Ordovician extinctions, while those that only lived in the ocean briefly before becoming benthic did survive.
There is no evidence that trilobites reabsorbed their old exoskeletons during moulting. Some scientists believe this inability to reabsorb their hardened shells made trilobites slower to rebuild their new exoskeletons, leaving them more vulnerable to predators compared to modern arthropods that can reabsorb their old shells.
History of usage and research
In 1698, Rev. Edward Lhwyd published a letter titled "Concerning Several Regularly Figured Stones Lately Found by Him" in The Philosophical Transactions of the Royal Society, the oldest scientific journal in the English language. His letter included a page with etchings of fossils. One etching showed a trilobite he discovered near Llandeilo, likely on the grounds of Lord Dynefor's castle. He described the trilobite as "the skeleton of some flat fish."
In 1749, Charles Lyttleton discovered a fossil later named Calymene blumenbachii (the Dudley locust), which is considered the start of trilobite research. In 1750, he sent a letter to the Royal Society of London about a "petrified insect" he found in "limestone pits at Dudley." In 1754, Manuel Mendez da Costa claimed the Dudley locust was not an insect but belonged to "the crustaceous tribe of animals." He named it Pediculus marinus major trilobos (large trilobed marine louse), a name used until the 19th century. Johann Walch, a German naturalist, conducted the first full study of this group and suggested the name "trilobite." He believed the name fit because of the three-lobed shape of the central axis and the two pleural zones on either side.
Descriptions of trilobites may date back to the third century BC, but definite records begin in the fourth century AD. Spanish geologists Eladio Liñán and Rodolfo Gozalo suggest that some fossils described in ancient Greek and Latin texts as "scorpion stone," "beetle stone," and "ant stone" refer to trilobites. More clear references to trilobites appear in Chinese sources. Fossils from the Kushan formation in northeastern China were used as inkstones and decorative items.
In the 1860s, American fossil hunters found many Elrathia kingi fossils in western Utah. Until the early 1900s, the Ute Native Americans of Utah wore these trilobites, calling them pachavee (little water bug), as amulets. A hole was drilled in the fossil’s head, and it was worn on a string. The Ute believed these necklaces protected against bullets and diseases like diphtheria. In 1931, Frank Beckwith found evidence of this practice. He photographed petroglyphs that likely showed trilobites and examined a burial site with a drilled trilobite fossil in the chest cavity of the deceased. Since then, trilobite amulets have been found in the Great Basin, British Columbia, and Australia.
In the 1880s, archaeologists found a drilled trilobite fossil in the Grotte du Trilobite (Caves of Arcy-sur-Cure, Yonne, France). The fossil, which was handled frequently, was dated to about 15,000 years old. Because the trilobite species could not be identified and is not found near Yonne, it may have been traded from another region, indicating its high value.