Brachyopterella
Brachyopterella is a genus of prehistoric eurypterid classified as part of the Rhenopteridae family. Two species, both from the Silurian period, are known; "B. pentagonalis" from Norway and "B. ritchei" from Scotland. Description. "Brachyopterella" was a small stylonurine eurypterid with a pentagonal carapace with little to no marginal rim and a concave base. The eyes were oblique, very long, banana-shaped, close-set and placed anteriorly on the carapace. Axes converged and crossed a short distance in front of the eyes. The ocelli were placed well forward between the eyes and the epistoma was well developed. The legs increased  in size gradually, with the first three having short opposable spines at the end of each joint and the last two walking legs being longer but lacking spines. The carapace was smooth and the legs were covered in granulations. The metasoma is unknown. Classification. "B. pentagonalis" was originally named as a species of the closely related "Brachyopterus", differences in the shape of the carapace and the eyes allowed them to be separated into different genera. Species. "Brachyopterella" contains two valid species, with one other species turning out to have been a pseudofossil. Invalid or reassigned species are listed below: Brachyopterella