Discovering New Trilobites

Inspired by a question from Kathy Moon

“Have any new trilobites been found lately? Are we still finding new ones?”

At least 20,000 species of trilobites have been named, but that number has been used for many years now and is probably much higher.  We are still finding new species of trilobites all the time!  Even new genera (plural of genus) and families of trilobites!  

There are two main ways in which new species of fossil animal or plant are found – in the field and in museums.  

In the Field

Most of the rocks that are exposed at the surface of the Earth in much of the United States have been described and mapped.  This is especially true of the surface rocks in New York State because scientists have been studying them, and describing the fossils they contain, since the 1830s.  In these early studies, surface rocks were divided into units called formations based on the rock type and often also the fossil content.  Sometimes, these geologists were also paleontologists, and they would describe and name new species they discovered (an example is Winifred Goldring, the fourth, and first female, State Paleontologist of New York).  Other times, paleontologists followed behind the geologists and targeted rock units that had been noted to contain fossils.  So, it sounds like everything has already been discovered!  

Well, it turns out that these early studies were not as thorough as they are today.  For example, I studied two rock units in Oklahoma for my PhD research.  In 1977, a paleontologist named Shaw reported finding 12 genera of trilobites in these rocks.  Shaw was studying them in order to better understand the role the rocks played in oil and gas formation.  My project was to describe each layer of rock in detail, use the information I obtained to interpret what the local environment was like when each layer formed, and collect as many trilobites as I could hammer from the rocks over the course of five years so that I could perform statistical analyses.  I spent four summers collecting rocks and fossils.  After this more thorough examination, I was able to report finding 36 genera of trilobites.

Another example comes from a new species of trilobite from the Tully Limestone in New York.  The Tully Limestone was first described and named in 1839 and it has long been known to be fossiliferous.  One trilobite that is found in that rock unit looks very similar to another species, and it was assumed that they were the same species.  Fossils of this trilobite are very rare in the Tully, making them difficult to study.  An avid fossil collector from New York State recovered about 12 well-preserved specimens and observed that the Tully species is different from the already named species.  He donated the specimens to the New York State Museum for study, and one of my research students described and named it.

Basidechenella new species

This specimen is partly enrolled so the tail is tucked under the middle part of the body.

In the Museum 

You would probably be surprised at how often a paleontologist opens a drawer in a museum cabinet and discovers a new species!  This happens because no one scientist is an expert on every fossil animal.  If I collected a new species of brachiopod while searching for trilobites, I might save it and add it to the collection as a good specimen, but I would have no way of knowing that it was new to science.

This happened to my PhD advisor shortly after he started at the museum at the University of Oklahoma.  He opened a drawer and found a complete Probolichas trilobite that was also a new species.

Probolichas kristiae complete specimen that my advisor found in a museum drawer.

Closer to home is the story of the trilobites of the Potsdam Sandstone in New York.  This rock unit was described and named in 1838 and trilobites were first discovered in it and collected from it in 1912.  But no one ever really studied them beyond reports that they exist!  One of my research students and I are working on them now, and we have identified three new species and one that is a new species and genus.

Talbotina new species     Coosina new species          Pemphigaspis new sp.      New Genus and Species

Naming Fossils

One of my favorite steps in conducting research on fossils is creating names for new species, genera and families.  

The first animal I named is a 230-million-year-old fossil lobster that I studied for my master’s degree.  I got to travel to the wilderness of northeastern British Columbia to collect them, too!  This lobster was very unique in that it had physical features that are characteristic of two separate families of lobsters, leading us to hypothesize that it is the common ancestor of both groups.  My co-author and I named the new genus and species Chimaerastacus pacifluvialis.  A chimaera is a mythical creature that is made up of the parts of more than one animal.  For example, a centaur is part human and part horse.  The word “astacus” means lobster in Greek, “pacis” means peace and “fluvialis” means river in Latin.  So, we named it the lobster that is made up of the parts of two different lobsters from the Peace River.  

This is a view from one of the areas where we collected the lobster fossils.

One trilobite I named Anataphrus kermiti because it looks like Kermit the Frog.  

Anataphrus kermiti in life position (left) and enrolled into a ball for protection (right).

Another, Thaleops mobydicki, got its name because studying that group of trilobites was very stressful and made me act like Captain Ahab – pursue the goal, even if it kills you and possibly others.

Top view (left) and side view (right) of Thaleops laurentiana.  This trilobite is from New York.  I’m using images of T. laurentiana because we have complete specimens.  T. mobydicki is only preserved disarticulated, which means that the head, tail, and middle segments are all separated from each other.