N.B.: The syllable -pagopus was formed from ancient Greek, means "frost foot" or "ice foot" and is masculine in gender (Tobias Joho, Institute of Classical Philology, University of Bern, Switzerland). Considered a senior synonym of Melognathus Chamberlin, 1917 by Raven, 1985a: 156, and of Haplopelma Simon, 1892 by Smith & Jacobi, 2015: 28 [urn:lsid:nmbe.ch:spidergen:00229] (type Selenocosmia doriae Thorell, 1890). Melognathus revalidated by Gabriel & Sherwood, 2019c: 145. Haplopelma considered a senior synonym of Melopoeus Pocock, 1895 by Raven, 1985a: 116 (but see also Schmidt, 2010b, who considered the type species a member of Ornithoctonus Pocock, 1892 and therefore considered Melopoeus the earliest available name for the remaining species, and Schmidt, 2015b, who removed Melopoeus from the synonymy with Haplopelma. Haplopelma, Cyriopagopus, Melopoeus and other "ornithoctonine" genera are in urgent need of revision (e.g. Hauke, 2017: 48). Genus transfers and synonymies without thorough analysis and without including the type species will not be taken over.