Triarthrus

== Translingual == === Etymology === tri- (“three”) +‎ Ancient Greek ᾰ̓́ρθρον (ắrthron, “joint”) +‎ -us m. === Proper noun === Triarthrus m A taxonomic genus within the family Olenidae – certain extinct ptychopariid trilobites. === See also === Triarthrus on Wikipedia.Wikipedia Triarthrus on Wikispecies.Wikispecies Category:Triarthrus on Wikimedia Commons.Wikimedia Commons