Fast Facts about Cryptolithus Trilobites
Name:
Cryptolithus is pronounced "crypto-LITH-us." The name means "hidden stone", from roots meaning hidden and stone.
Common name:
Lace collar trilobite. The small holes, or fenestrae, around the edge of the cephalon look like a delicate lace collar.
Taxonomy:
Arthropoda - Trilobita - Asaphida - Trinucleioidea - Trinucleidae - Cryptolithus.
Species:
Commonly referenced species include Cryptolithus bellulus and Cryptolithus tessellatus.
Age:
Ordovician Period.
Distribution:
North America, especially Upper Ordovician deposits such as the Martinsburg Formation and Kope Formation.
Body size:
Small. Most Cryptolithus trilobites are less than one inch long, or about 25 mm.
Diet:
Filter feeder. The perforated fringe around the cephalon likely helped filter food particles from disturbed sediment or water near the sea floor.
Physical appearance:
Cryptolithus has a wide cephalon with many small openings and very long genal spines. In complete specimens, the spines can be longer than the body of the trilobite.
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Cryptolithus Trilobite Facts and Information
Cryptolithus trilobites are a genus of small, blind Ordovician trilobites. They are often called "lace collar" trilobites because of the small openings, or fenestrae, around the edge of the cephalon. These openings are the most distinctive feature of the genus and are easy to see in well-preserved specimens.
The lace-like fringe was not just decorative. It likely functioned as part of a feeding system. The trilobite probably disturbed sediment on the sea floor and used the perforated cephalic fringe to filter small food particles. This made Cryptolithus a specialized filter feeder living close to the bottom of Ordovician seas.
In addition to the wide perforated cephalon, lace collar trilobites are known for their extremely long genal spines. These spines can extend beyond the length of the body from cephalon to pygidium, giving complete specimens a delicate and dramatic appearance.
Although Cryptolithus is a small trilobite, it can be one of the most beautiful Ordovician fossils when complete. Unfortunately, complete specimens are uncommon. Most finds are fragments, especially pieces of the cephalon or isolated parts of the perforated fringe.
Where to Find Cryptolithus Trilobite Fossils
Cryptolithus fossils occur in Upper Ordovician rocks of North America. Two of the most important fossil sources are the Martinsburg Formation in Pennsylvania and the Kope Formation in the Cincinnati region.
The world-famous specimens of Cryptolithus bellulus come from the Martinsburg Formation. One famous collecting locality was Swatara Gap in Lebanon County, Pennsylvania. Here, the fossils are often preserved as casts coated with a fine rusty iron-oxide powder. This limonite coating gives the trilobites their distinctive color and makes complete specimens especially attractive.
Cryptolithus tessellatus is common in the Kope Formation, an extensive Upper Ordovician formation exposed in parts of Ohio, Kentucky, and Indiana. Complete specimens are uncommon in the Kope Formation, but fragments can be abundant in fossil hash plates composed of crinoid fragments, brachiopods, bryozoans, and trilobite pieces.
The image above and the image below show hash plate sections from the Kope Formation. The matrix is composed mostly of crinoid fragments, along with brachiopods, bryozoans, and pieces of Cryptolithus trilobites.
Recommended Trilobite and Fossil Hunting Books:
The Trilobite Collector's Guide
Andy Secher, 2024
This book by Andy Secher, a leading trilobite collector, offers a captivating journey into the world of these ancient arthropods. With over 400 stunning photos, entertaining top-ten lists, invaluable collecting tips, and ways to spot a fake trilobite, it's a must-have for fossil enthusiasts!
Trilobites: Common Trilobites of North America (A NatureGuide Book)
Jasper Burns, 2000
An excellent guide for identifying North American trilobites, featuring meticulous line drawings and concise information on classification, geologic range, and distribution. Ideal for enthusiasts seeking detailed insights and accurate identification of these ancient arthropods.
101 American Fossil Sites You've Gotta See
Albert B Dickas, 2018
This is a great updated fossil sites book with at least one fossil site in each state. Each site is broken into 2 pages. One has detailed information, such as directions, GPS coordinates, formation information, etc...
The other is dedicated to images of the site and the fossils found there. It also gives information on fossil 'viewing' sites such as dinosaur trackways, museums, and active excavations.
Plus, my fossil photos are peppered throughout this book!
