The Ordovician trilobite Oenonella and the new family Oenonellidae, with new species from western Newfoundland, Canada

Abstract

AbstractThe tiny Ordovician trilobite Oenonella Fortey, 1980 has previously been known only from cranidia and pygidia of its Middle Ordovician type species. Two new species, Oenonella wasisnamei and O. otherfellersorum, from the Darriwilian Table Cove Formation, western Newfoundland, Canada, are known from silicified material that provides new information on the librigena, ventral morphology, and intraspecific variation within the group. The stratigraphic range of the genus is extended downward by an occurrence in the Floian of the Shallow Bay Formation, western Newfoundland. New knowledge of Oenonella confirms its likely phylogenetic relationship with Proscharyia Peng, 1990, known from the Tremadocian of South China. In addition, the overlooked Amechilus Ross, 1951, seems to belong to the same group. Both Oenonella and Proscharyia have in the past been assigned to the aulacopleuride family Scharyiidae Osmólska, 1957. New silicified material effectively rules out this possibility. The broader affinity of the group remains obscure, but together the three genera are assigned to the new family Oenonellidae.UUID:http://zoobank.org/ee3ce7ed-3d9b-4730-a5cb-cf680df418ec