Actinolepis spinosa n. sp. (Arthrodira) from the Early Devonian of Latvia

Actinolepis spinosa n. sp. from the Early Devonian (Siegenian) of western Latvia, USSR, is rather close to the Middle Devonian type species A. tuberculata Agassiz. In its fused preorbitals Actinolepis is similar to Bollandaspis from the early Emsian of Belgium. Gnathalia are known only in few actinolepids. In A. spinosa anterior and posterior superognathalia and the inferognathal are described. The roughly triangular posterior superognathal resembles that of Dicksonosteus arcticus Goujet, and the long and slender inferognathal is close to the equivalent plate in an undetermined actinolepid from Utah figured by Denison (1958).