Calymene

Calymene is a well-known genus of extinct marine arthropods called trilobites, which flourished in ancient oceans from the Ordovician to the Devonian periods (around 485 to 360 million years ago).

Core Facts about Calymene

• Scientific Name: Calymene (derived from Greek for "beautiful crescent").
• Classification: Family Calymenidae, Order Phacopida.
• Average Size: Small creatures, typically 2 to 5 cm in length.
• Anatomy: They had a tough calcite exoskeleton divided into three main sections: the head (cephalon), a thorax with 13 segments, and a tail (pygidium).
• Diet & Behavior: They were slow-moving bottom-dwellers (benthic scavengers or filter-feeders) that crawled along the shallow ocean floor.
• Defense Mechanism: When threatened, Calymene could roll up into a tight ball (like a modern pill bug or woodlouse) to protect its soft underside.

Why They Are Famous

• Dudley Bug: nThe species Calymene blumenbachii was found so frequently in limestone quarries in Dudley, England, that 18th-century workers nicknamed it the "Dudley Bug" or "Dudley Locust". It even became a symbol on the town's coat of arms.
• State Fossil: The species Calymene celebra is the official state fossil of Wisconsin, USA.
• Index Fossils: Because they were geographically widespread and abundant, scientists use them to date rock layers.