Richard Leakey et al. (1973) first described KNM-ER 1470, and attributed it to Homo sp. indet. based on the large endocranial volume (> 800 cc) and difference from known Australopithecus specimens. Also the associated post cranial bones, KNM-ER 1472, 1473 and 1481 did not claerly differ from modern humans. Subsequent analyses of the Homo habilis hypodigm (sensu lato) led Wood (1991) to conclude multiple species were present and in Wood (1992) he deployed the name Homo rudolfensis (Alekseev, 1986).
Alexeev (1986), in his book length treatment of the fossil record, suggested KNM-ER 1470 and KNM-ER 1813 belonged to a new species, Pithecanthropus rudolfensis. Wood (1992) recognized the Alexeev publication as a valid nomencaltural act and considered the nomen 'rudolfensis' as available and valid, though this was contested at the time (Kennedy 1999).
Due to ongoing debates about the validity of H. rudolfensis as a species separate from H. habilis, the former is sometimes referred to as a subspecies of Homo habilis though arguments have been made that it may also be subsumed into Australopithecus, as Australopithecus rudolfensis (Wood and Collard 1999). This discourse comes from the australopithecine features H. rudolfensis retained in contrast with the early Homo characteristics presented in its body plan (McHenry and Coffing, 2000).
Aiello and Collard (2001) invoked the nomen as Kenyanthropus rudolfensis.
The name 'rudolfensis' is widely established and actively used with ca 60 citations in the past 50 years by at least 10 authors, including Lieberman et al. (1996), Karl (2012), Argue et al. (2009), Wood and Baker (2011), Ungar et al (2006), Anton (2007), Prat (2007), Will and Stock (2015), Agusti (2018), Smith and Grine (2008) etc.
