Ernst Haeckel's mysterious species, Part II: African Chirodropida (Cnidaria, Cubomedusae)

Ernst Haeckel described four new chirodropid species in 1880. Chirodropus gorilla was seen only on a few occasions along the Western coasts of Africa, while Chirodropus palmatus (from St. Helena Island) was never recorded again. Type specimens of both species are lost, leading some scientists to doubt the validity of C. palmatus. New specimens assignable to C. gorilla from European and South African Museum collections shed light on the identification of both species. Among the C. gorilla samples, small mature individuals with more pedalial branches than in the larger specimens were discovered. Further observations on living specimens of the smaller chirodropid from Cameroon suggested that they must be C. palmatus because there were only two chirodropid species described from West African waters; comparison with Haeckel's descriptions and drawings confirmed the identification. Additionally, our data showed that Chirodropus palmatus must be classified into the family Chiropsalmidae and accommodated in its own genus, Chimaerus gen. nov. We also revised definitions of the families Chirodropidae and Chiropsalmidae and re-described both species.