10 Trilobite Facts for The Fossil Lover in All of Us

Trilobite of Wheeler Shale

Across the vastness of our ocean floors, Trilobites, recognized by their distinctive 3-lobed, 3-segmented form, roamed for nearly 300 million years.

These ancient marine animals made their debut on earth around the beginning of the Cambrian Period (some 542 million years ago). During that time they dominated the seas, surviving and thriving beneath the waves. In the succeeding geologic periods we would see their numbers decline, although some were able to persist well into the Permian Period (ending around 251 million years ago).

Today, these now-extinct marine animals are highly sought out by collectors, as fossilized creatures from the deep.

Trilobite Facts

1. More than 20,000 Unique Species of Trilobites Have Been Discovered

Found on every continent, to date we have discovered no less than 20,000 species of this marine animal, ranging in size from 28 inches long (Isotelus rex) to those less than a millimeter in length. Notable features include rounded shells (some smooth some with defensive spines), with many deep-sea species being blind.

2. Making Their Debut: 540 million years ago

Our best estimations from carbon dating place the Trilobite appearing at the start of the Cambrian Period. Noted for explosive diversity and the emergence of new creatures, this period included a wide range of arthropods, mollusks, and some species that are hard to classify. Taking full advantage of conditions at that time, Trilobites quickly expanded to become one of the most common and diverse animals at the time.

3. Unique Defensive Mechanism

At the first sign of danger, these creatures would ball up similar to modern-day pill bugs. Flexing their posterior end under their head, this defensive position effectively utilized their hard outer shell/exoskeleton to provide superior protection against predators.

4. Confusion Amongst the Scientific Community

These little sea creatures gave the scientific community a bit of a head-scratcher at first. Naturalist and linguist Edward lhuyd (1679) first misidentified it as “the skeleton of some Flat-fish”. Later, in 1750, Bishop Charles Lyttleton wrote to London’s Royal Society describing what he believed to be a “petrified Insect”.

5. Not Actually a Fossil in the Traditional Sense

The majority of Trilobite fossils are the remnants of molted exoskeletons. Similar to a hermit crab, these creatures would periodically outgrow their own shells. When this happened, a molting process would ensue and the discarded ‘husks’ would often become preserved. In fact, most ‘fossils’ of trilobites are not the creature itself (which are comparatively rare), but rather the discarded shell.

6. Not One, but THREE States in the USA Have Made the Trilobite It’s Official Fossil

In 1985, Ohio marked the first state to adopt the entire Isotelus genus as its state fossil, with Wisconsin opting to choose Calymene celebra as theirs. Three short years later, in 1988, Pennsylvania adopted Phacops rana as its official state fossil, in large part thanks to the lobbying of an elementary school class.

7. Diverse Food Sources

It is thought that early trilobites were hunters, seeking out aquatic worms that were eaten live. However, some theorize that other species may have evolved to survive on algae and plankton, utilizing a filter-feeding system for nourishment. Many researchers believe that there were trilobite species that occupied every possible feeding niche, hunters, plant eaters, scavengers, and filter feeders.

8. A Victim of Mass Extinction

Over 250 million years ago, a mass extinction event occurred. Sometimes referred to as the “Great Dying”, this catastrophic event resulted in some 90% of all species on earth perishing.

Possible causes range from exploding supernovas, to increased volcanic activity. Regardless of the catalyst, the event, known by the scientific community as the “Permian Extinction” resulted in trilobites meeting their ultimate demise.

9. An Unlikely Use: Native American Amulets

A lesser-known tribe from what is now defined as the state of Utah once collected these Cambrian trilobites for an unlikely use. The Pahyant Ute people believed that the fossils had supernatural powers, leading them to make amulets and protective charms from the fossils. Interestingly, the tribe called them “Timpe-Konitza-Pachuee”, roughly translated to “little water bug living in a house of stone”.

10. A Connection to the Star Wars Trilogy!!!

Samuel Turvey, a paleontologist, discovered several unique species of trilobites during his explorations in China. One such species he opted to name “Han”. Conveniently enough, “Han” also represents China’s largest ethnic group. Given the opportunity, Turvey couldn’t resist naming one particular species “Han solo”.

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