Some trilobite species lived in deeper-water environments that are not well preserved in the fossil record. There are also intervals of time that are not well represented in some areas. This is the case for the earliest part of the Ordovician in Morocco. Because of this, any well-preserved trilobite specimens from these rocks are important for understanding how they relate to other parts of the world. They are also important for our understanding of migration and evolution of trilobites during this time. Here we present the first well-preserved trilobites of the family Olenidae from Morocco. Species from this family were often restricted to deeper or low-oxygen environments. This is the first discovery of olenid trilobites from Africa that are well preserved enough to be able to identify the species.

Here we describe the first articulated olenid trilobite specimens recovered from the lowermost Fezouata Shale Formation (lower Tremadocian, Ordovician) of Morocco. Prior to the discovery of this sample, only two partial olenid trilobite specimens had been found from this part of the rock record. The specimens are well preserved enough to confidently identify as Leptoplastides salteri (Callaway, 1877), extending the species geographic range from Avalonia into Gondwana. We argue that the Moroccan occurrences formerly referred to as “Beltella sp.” in the literature are likely to be those of L. salteri. This species is the only olenid trilobite known from African Gondwana.