Morphology-based systematics (MBS) and problems with fossil hominoid and hominid systematics.

Abstract

The generalized/primitive nature of the hominoid dentition and often fragmentary nature of fossils, coupled with enthusiastic optimism for making revolutionary finds, has wreaked havoc with recognition of early human ancestors and reconstruction of fossil hominoid phylogeny. As such, the history of paleoanthropology is one of repeated misidentification of fossil ancestors and of occasional fraud. Although this history has led many workers to lose confidence in morphology based systematics (MBS), past and present misidentifications are actually due to a disregard of systematic methodology. Systematics depends on the continuity of life and gains its objectivity largely from the order alpha taxonomy imposes on morphologic discontinuities in closely related taxa (i.e., species and genera). Transformation of characters fixed in species into character complexes, as manifested in taxa nested at different levels of relationship, form the foundation for higher-level taxonomy and for phylogeny. Because in most cases, hominoid fossils are unable to provide the data needed to resolve alpha taxonomy, classification and phylogeny of fossil taxa must be guided by analogies to living taxa. Hominid and hominoid fossil taxonomy and phylogeny, however, has been based largely on preevolutionary notions and on misinterpretations of the polarity of assumed diagnostic characters. More often than not, fossils lack resolution for the taxonomic level or rank they are assigned to and taxa are erected without appropriate analogies to living forms. As such, phylogenies based on these classifications are unlikely to be correct. More in-depth anatomical studies that are in accordance with systematic methodology are likely to hold the key to correctly classifying fossils and unraveling hominoid and hominid phylogeny.