Forest monkeys and Pleistocene refugia: a phylogeographic window onto the disjunct distribution of theChlorocebus lhoestispecies group

Abstract

The reconstruction of evolutionary relationships among a group of closely-related taxa provides a valuable window onto their biogeographic history. This is the first such molecular phylogenetic study to survey all three taxa of the Chlorocebus lhoesti species group, a group of Old World monkeys that includes C. lhoesti, Chlorocebus preussi, and Chlorocebus solatus. Representatives of each species were surveyed for two Y-chromosomal genes, TSPY (~2240 bp) and SRY (~780 bp), and one X-chromosomal intergenic region (~9300 bp) homologous to a portion of human Xq13.3. Maximum likelihood topologies inferred from these sequences confirm that the lhoesti group is monophyletic within the tribe Cercopithecini, as suggested by earlier karyotype studies. Within this group, C. lhoesti (Albertine region) and C. preussi (Cameroon, Nigeria, Bioko) cluster to the exclusion of C. solatus (Gabon). This phylogeographic pattern, evaluated in the context of Pleistocene glacial cycles and lhoesti group ecology, suggests: (1) the common ancestor of the group probably arose in west central Africa, (2) dispersal to the Albertine region is likely to have occurred during a glacial maximum, rather than an interglacial pluvial, and (3) this dispersal probably occurred via a path north of the Congo Basin. Divergence date calculations suggest C. solatus separated from the ancestral stock at~2.1 Ma, whereas C. preussi and C. lhoesti bifurcated later, at~0.5 Ma. Taken together, these evolutionary analyses draw attention to one period in the Pleistocene (~0.5 MYA) when a dispersal corridor suitable to montane taxa is likely to have connected the highlands of east central and west central Africa.

Mitochondrial and Nuclear Genes-Based Phylogeography of Arvicanthis niloticus (Murinae) and Sub-Saharan Open Habitats Pleistocene History

“…Interestingly, the picture drawn from studies on rodents often resembles those obtained on other mammals that we are aware of: refuges and allopatry during successive climatic cycles in the past were advocated to explain the differentiation of genetic lineages in cercopithecine monkeys (e.g., [94], [95]), baboons [96], hyenas [97], wild dog [98], common warthog [99], giraffe [100], buffalo [101] and many large antelopes like topi, hartebeest [102], [103], impala, kudu [104], waterbuck [105], kob [106], African bushbuck [107], common eland [108] and roan [109]. Similar conclusions were also reached in plants (e.g., shea tree: [110]; giant lobelia: [111]; coffee tree: [112]), insects (e.g., maize stalk borer: [113]), reptiles (e.g., puff adder: [114]; Southern rock agama: [115]) and birds (e.g., starred robin: [116]; ostrich: [117]).…”

Strong influence of palaeoclimate on the structure of modern African mammal communities

“…Molecular evidence suggests that shifts in forest vegetation during glacial and interglacial climate change strongly influenced African primates, including vicariance and dispersal in guenons [38,70] and gorillas [36], and demographic patterns in chimpanzees [80] and mandrills [81]. In addition, bioclimatic envelope models of African mammals and birds provide evidence for three major forest refugia in Central and West Africa [40], which would have represented the only viable habitats for most of Africa's primates during glacial periods.…”

“…Africa is also home to a great diversity of species in 17 of the world's 20 orders of terrestrial mammals [19][20][21], and is virtually the only continent relatively unscathed by the late Quaternary extinction events [22,23]. Nevertheless, late Quaternary palaeoclimate change has been noted as a particularly important time period in the evolution and biogeography of African mammals [24][25][26][27][28][29][30][31][32][33][34][35], especially recurrent expansions and contractions of major vegetation biomes as climates changed [29,[36][37][38][39][40].…”

Pan-African Voyagers: The Phylogeography of Baboons

“…The mid-Pliocene vegetation shifted from closed canopy forest to open savannah vegetation in large parts of Africa, and arid-adapted flora and fauna expanded as glaciation in the north proceeded (deMenocal 1995). The last 2.5 million years saw about 20 glacial cycles with major forest expansions and retreats in Africa (Hamilton 1982, Hamilton & Taylor 1991 as evidenced by pollen core data and the current distribution of forest organisms (Sowunmi 1981, Hamilton 1981, 1988 Hamilton & Taylor 1991, Grubb 1982, Tosi 2008. Glacial period environments were characterised by dry, tropical scrub and grassland with limited gallery forest along drainages.…”