Lichida
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Extinct (fossil)
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Lichida is an order of typically spiny trilobite that lived from the Ordovician to the Devonian period.
These trilobites usually have 8-13 thoracic segments. Their exoskeletons often have a grainy texture or have tubercles. Some species are extraordinarily spiny, having spiny thoracic segments that are as long or longer than the entire body, from cephalon (head) to pygidium (tail). The sections of the pygidia are leaf-like in shape and also typically end in spines.
The spiny character of these trilobites could possibly have come about as a defense against the rapidly evolving fishes of the Devonian period.
[edit] References
- Lichida Guide - from the Guide to the 8 Orders of Trilobites by Sam Gon III.
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