WAegirocassis is an extinct genus of anomalocarid arthropod belonging to the family Hurdiidae that lived 480 million years ago during the early Ordovician. It is known by a single species, Aegirocassis benmoulai. Van Roy initiated scientific study of the fossil, the earliest known of a "giant" filter-feeder discovered to date. Aegirocassis is considered to have evolved from early predatory anomalocarids.
WAmpyx is an Ordovician-Silurian genus of Asaphid trilobites of the family Raphiophoridae. Species of Ampyx are characterized by three extended spines on the head-shield, one spine derived from each free cheek, and one spine emanating from the glabellum. Species include Ampyx linleyensis.
WColpocoryphe is a genus of trilobites in the family Calymenidae.
WFurca is an extinct genus of Marrellomorph arthropod known from the Sandbian stage of the Czech Republic. At least three distinct species have been described although they may all be synonyms of the type species, Furca bohemica. A tentative additional species, "Furca mauretanica": was proposed for specimens discovered in Morocco, but this species remains a nomen nudum until formally published.
WGeragnostus is a genus of very small agnostid trilobites whose fossils are found Ordovician-aged marine strata from Eurasia, North America and Argentina.
WMegistaspis is a genus of trilobites in the order Asaphida and family Asaphidae.
WOgyginus is an extinct genus of asaphid trilobites that lived during the Ordovician period. Commonly found in Wales. The type specimen was first described by Murchison in 1839 as Asaphus corndensis, though the species was later reassigned.
WPlacoparia is a genus of trilobites of average size that lived during the late Lower to the early Upper Ordovician on the paleocontinents Gondwana, Avalonia and Laurentia, now the Czech Republic, France, Germany, Morocco, Portugal, Spain and Wales. Its headshield is semi-circular to rectangular with rounded frontal corners. It lacks eyes, but eye ridges are present. The fact that the facial sutures are opisthoparian is an exception in the otherwise proparian Cheirurina. The thorax has 11 or 12 segments, with the axis slightly wider than the ribs to its sides. The tips of the pleurae are free, which resembles an old-fashion central heating radiator. The axis in the small tailshield consists of four rings and a minute endpiece. The four pleurae end in spatulate spines that fit to corresponding indentations in the cephalon.
WSelenopeltis is an extinct genus of odontopleurid trilobites in the family Odontopleuridae.