Pseudogygites is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of the class Trilobita

Trilobite

Trilobites are a well-known fossil group of extinct marine arthropods that form the class Trilobita. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period , and they flourished throughout the lower Paleozoic era before...

 from the Middle and Upper Ordovician

Ordovician

The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...

.

Dimensions

Pseudogygites can reach 25 centimetres (10 in) in length and 10 cm (4 in) in width.

Description

The pygidium

Pygidium

The pygidium is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. It contains the anus and, in females, the ovipositor...

 and the cephalon are about equal in size and shape. The glabella is expanded forward, reaching to the anterior margin. Pseudogygites has short genal spines and small compound eyes located in the center of the cephalon with the glabella in between. The pygidium contains faint pleural furrows and no axial rings.

Distribution

Pseudogygites is found in late Ordovician oil shale

Oil shale

Oil shale, an organic-rich fine-grained sedimentary rock, contains significant amounts of kerogen from which liquid hydrocarbons called shale oil can be produced...

s in New York

New York

New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

, Ontario

Ontario

Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

, and Southampton Island

Southampton Island

Southampton Island is a large island at the entrance to Hudson Bay at Foxe Basin. One of the larger members of the Canadian Arctic Archipelago, Southampton Island is part of the Kivalliq Region in Nunavut, Canada. The area of the island is stated as by Statistics Canada . It is the 34th largest...

 in the Canadian Arctic.

Species

Four species have been described:

• Pseudogygites latimarginata (Hall, 1847)
• Pseudogygites hudsoni
• Pseudogygites akpatokensis
• Pseudogygites arcticus