Onychopterella (/ˌɒnɪkɒptəˈrɛlə/ ON-ə-kop-tə-REL-ə, from Ancient Greek: ὄνῠξ (ónyx), "claw", and πτερόν (pteron), "wing") is a genus of predatory eurypterid ("sea scorpion"), an extinct group of aquatic arthropods. Fossils of Onychopterella have been discovered in deposits from the Late Ordovician to the Late Silurian. The genus contains three species: O. kokomoensis, the type species, from the Early Pridoli epoch of Indiana; O. pumilus, from the Early Llandovery epoch of Illinois, both from the United States; and O. augusti, from the Late Hirnantian to Early Rhuddanian stages of South Africa.