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Lichida is an order of typically spiny trilobite that lived from the Ordovician to the Devonian period. Terataspis grandis (which may be translated as "great monster shield" was a huge (relative to other trilobites 60 Centimetre long Lichid The conservation status of a Species is an indicator of the likelihood of that species remaining extant either in the present day or the near future Arthropods are Animals belonging to the Phylum Arthropoda (from Greek ἄρθρον arthron, " Joint " Trilobites ("three-lobes" are extinct Arthropods that form the class Trilobita. Trilobites ("three-lobes" are extinct Arthropods that form the class Trilobita. The Ordovician is a geologic period and system, the second of six of the Paleozoic era, and covers the time between 488 The Devonian is a geologic period and system of the Paleozoic era spanning from to million years ago.
These trilobites usually have 8-13 thoracic segments. The thorax is a division of an Animal 's body that lies between the head and the Abdomen. 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). Cephalon Inc ( is a US biopharmaceutical company co-founded in 1987 by Dr The pygidium is the posterior body part or shield of Crustaceans and some Arthropods such as Insects and the extinct Trilobites It contains the The sections of the pygidia are leaf-like in shape and also typically end in spines.
It is often said and quoted that the spiny character of these trilobites could possibly have come about as a defense against the rapidly evolving jawed fishes of the Silurian and Devonian periods. Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two However, this fails to explain why the the lichid trilobites, especially those of the family Odontopleuridae, first began evolving large spines (and in some cases, spiny spines) during the start of the Ordovician period, long before the advent of jawed vertebrates. In Biological classification, family ( Latin
References
- Lichida Guide - from the Guide to the 8 Orders of Trilobites by Sam Gon III.
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