The history of the discovery of early fossils attributed to the genus Homo has been contentious, with scholars disagreeing over the generic assignment of fossils proposed as members of our genus. In this manuscript I review the history of discovery and debate over early Homo and evaluate the various taxonomic hypotheses for the genus. To get a sense of how hominin taxonomy compares to taxonomic practice outside paleoanthropology, I compare the diversity of Homo to genera in other vertebrate clades. Finally, I propose a taxonomic model that hews closely to current models for hominin phylogeny and is consistent with taxonomic practice across evolutionary biology.
K E Y W O R D Searly Homo, genus, taxonomy
| I N TR ODU C TI ONThe recent discovery of hominin fossils proposed as candidates for early members of the genus Homo (Berger et al., 2010;Leakey et al., 2012;Villmoare et al., 2015) has renewed debate on the taxonomy of our genus (Anton, Potts, & Aiello, 2014;Berger et al., 2012;Collard & Wood, 2015; Hawks et al., 2015;Kimbel & Villmoare, 2016;Schwartz & Tattersall, 2015). Here I review the history of discovery and debate for early members of our genus, and follow with a discussion of how the taxonomic rank of genus has been, and might be, applied to the human lineage. have now, as it appears to me, satisfactorily shown that not only in its general, but equally so in its particular characters, has the fossil under consideration the closest affinity to the apes" (King, 1864, pp. 96-97).In his 1863 lecture he proposed the taxonomic assignment "Homo Neanderthalensis" (sic), out of a sense of conservatism (largely based on the absence of preserved facial anatomy), but in 1864, in his published analysis of the vault, he reconsidered: "In that paper I called the fossil by the name Homo Neanderthalensis; but I now feel strongly inclined to believe that it is not only specifically but generically distinct from Man" (King, 1864, p. 96).However, the practice of applying the generic name Homo for newly discovered hominin fossils from Europe was largely retained (Wood, 2000) so that by 1907, when a hominin jaw was discovered in sand mines outside the village of Mauer, Germany, the species was designated H. heidelbergensis (Schoetensack, 1908) without controversy. The generic assignment was based largely on the human-like characteristics of the dentition, even though the lack of a chin and overall robusticity clearly placed the jaw outside the limits of known human variation (Harvati, 2007;MacCurdy, 1909;Smith Woodward, 1925). Subsequent attempts to transfer the specimen to the genus Paleoanthropus (Bonarelli, 1909;McKown & Keith, 1939) were not adopted by the scientific community. Discoverers felt relatively free to assign specific distinction to new discoveries, leading to the proliferation of fossil species in Homo in the late 19th and early 20th centuries -for example, H. mousteriensis, H. primigenius, H. antiquus, H. spelaeus, H. rhodesiensis, H. soloensis, and so forth. (Harvati, 2007;MacCurdy, 1908MacCurdy, ,...