Article: Silurian dalmanitacean trilobites from North America and the origins of the Dalmanitinae and Synphoriinae

The dalmanitacean trilobite genera Daytonia, Ommokris, Glyptambon, and Lygdozoon are described from the Silurian of North America. Daytonia and Ommokris are assigned to the Dalmanitinae; Glyptambon belongs to the Dalmanitidae but cannot be referred to an established subfamily; and Lygdozoon is assigned to the Synphoriinae, together with the genus Delops Rickards, 1965. Synphoriinids have previously been reported only from strata of Early and Middle Devonian age. The predominantly Ordovician subfamily Mucronaspidinae is erected for some of the genera formerly included in the Dalmanitininae, and it is proposed that the Dalmanitinae and the genus Glyptambon arose from different members of the Mucronaspidinae, whereas the Synphoriinae had its origins in the Dalmanitininae.