A proper study for mankind: Analogies from the Papionin monkeys and their implications for human evolution

Abstract

This paper's theme is that analogies drawn from the cercopithecine tribe Papionini, especially the African subtribe Papionina (baboons, mangabeys, and mandrills), can be a valuable source of insights about the evolution of the human tribe, Hominini, to complement homologies found in extant humans and/or African apes. Analogies, involving a "likeness of relations" of the form "A is to B, as X is to Y," can be usefully derived from nonhomologous (homoplastic) resemblances in morphology, behavior, ecology, or population structure. Pragmatically, the papionins are a fruitful source of analogies for hominins because they are phylogenetically close enough to share many basic attributes by homology, yet far enough that homoplastic modifications of these features are easily recognized as such. In "The Seedeaters," an analogy between Theropithecus among baboons and Australopithecus africanus among hominines was the source of a widely discussed (and often misrepresented) dietbased scenario of hominin origins that explained previously unassociated hominin apomorphies, interpreted basal hominins as nonhuman rather than prehuman primates, and accommodated a basal hominin adaptive radiation of at least two lines.Current usage recognizes an even more extensive evolutionary radiation among the basal hominins, originating no earlier than about 7 ma, with multiple lineages documented or inferred by 2.5 ma. Although multilineage clades (especially the Paranthropus clade) within this complex are widely recognized, and emerge from sophisticated, parsimony-based analyses, it is suspected that in many cases, developmental or functional homoplasies are overwhelming the phylogenetic signal in the data. The papionin analogy (specifically the splitting of the traditional, morphology-based genera Cercocebus and Papio mandated by molecular evidence) illustrates the power of these factors to produce erroneous cladograms. Moreover, the rapid deployment of basal hominins across varied African habitats was an ideal scenario for producing morphologically undetectable homoplasy. There seems to be no foolproof way to distinguish, a priori, homologous from homoplastic resemblances in morphology, but one pragmatic strategy is to severely censor the datset, retaining only resemblances or differences (often apparently trivial ones) that cannot be reasonably explained on the basis of functional resemblance or difference, respectively. This strategy may eliminate most morpological data, and leave many fossil taxa incertae sedis, but this is preferable to unwarranted phylogenetic confidence.

Fission‐Fusion Dynamics

“…Such a situation is especially obvious in hamadryas baboons (Kummer 1995), though similar patterns may be seen in all Papio baboons. The fact that baboons live in as large a variety of habitats as our earliest ancestors did (from rainforests to open savannah areas), including more open and drier habitats than those where modern chimpanzees occur, seems relevant, given that Papio and our earliest ancestors first emerged at about the same time (Jolly 2001;Moore 1996). We envisage an evolutionary path in which a chimpanzee-like hominid ancestor, with a low degree of spatial cohesiveness but highly structured social relationships, started to exploit not just forests but also more open savannah/woodland environments.…”

Three Sykes's MonkeyCercopithecus mitis× Vervet MonkeyChlorocebus pygerythrusHybrids in Kenya

“…With the discovery of the Cercopithecus mitis × Chlorocebus pygerythrus hybrids in Kenya, three of the seven spe cies pair combinations for sympatric hybridization among A number of cases of sympatric hybridization are known for the edges of the range of one or both of the parental species of the species (Jolly et al 1997;Jolly 2001;Detwiler 2002;Detwiler et al 2005). In these cases, hybridization is seen as are scarce or absent.…”

“…How do anthropogenic environments affect rates of hybridization? What are the implications of 'anthropogenic hybridization' for the conser vation of primate diversity (Allendorf et al 2001;Jolly 2001;Detwiler et al 2005)? The presence of these three apparent intergeneric hybrids also leads to questions related to cerco above questions would be shed by comparative research on these three hybrids and their parental species.…”

“…Natural hybridization is increasingly recognized as potentially playing an important function in the evolution Jolly et al 1997;Allendorf et al 2001;Barton 2001;Jolly 2001;Detwiler et al 2005;Arnold and Meyer 2006). Among Afri ca's primates, natural hybridization appears to occur most often along the edges of the geographic ranges of parapatric subspecies of the same species, or of parapatric species of the same 'species group' (i.e., 'superspecies').…”

Superoxide dismutase 1 is positively selected to minimize protein aggregation in great apes

“…Non-human primates such as macaques are commonly used to study neurological diseases and identify the relevant differences between primate proteomes [5]. Primate evolution is complex and marked by diversifications due to emergence of generalist strategies relating to changes in habitats and foraging behavior and social innovations [10]. Thus, primate evolution is notable for its variable evolutionary rates caused by geographic diversification, effective population size bottlenecks, and long generation times [11].…”