Cercopithecini
Cercopithecini is a tribe of Old World monkeys within the subfamily Cercopithecinae of the family Cercopithecidae, primarily consisting of arboreal and semi-terrestrial guenons and related species native to sub-Saharan African forests and woodlands.[1][2] The tribe encompasses six genera—Allenopithecus, Allochrocebus, Cercopithecus, Chlorocebus, Erythrocebus, and Miopithecus—comprising approximately 35 species, many of which are noted for their diverse coat patterns, cheek pouches for food storage, and adaptations for folivory and frugivory.[2][3] These monkeys exhibit bilophodont molars suited for shearing and crushing plant material, reflecting evolutionary shifts toward seed- and fruit-based diets that parallel broader cercopithecoid adaptations.[3][1] Most species are diurnal and social, living in multimale-multifemale groups or harems led by a single adult male, with females forming stable kin-based cores that emphasize cooperative behaviors and vocal communication.[1][4] Physical traits include medium body sizes (typically 0.8–13 kg), ischial callosities, and variable tail lengths, with pronounced sexual dimorphism in some genera like Cercopithecus.[5][4][3] Distributed across diverse habitats from dense rainforests to savannas, Cercopithecini species such as the patas monkey (Erythrocebus patas) occupy open grasslands, while guenons like Cercopithecus mitis (blue monkey) prefer forested canopies; however, many face threats from habitat loss and bushmeat hunting, rendering numerous taxa vulnerable or endangered.[1][4][3] Evolutionarily, the tribe diversified in the Miocene, with dietary innovations driving speciation and ecological niche partitioning among Africa's primate communities.[3]Taxonomy
Etymology and history
The name Cercopithecini derives from the genus Cercopithecus, established by Carl Linnaeus in 1758 as the type genus for the tribe, with the suffix -ini denoting a taxonomic tribe.[6] The term Cercopithecus originates from Ancient Greek kérkos (tail) and píthēkos (ape or monkey), translating to "tailed ape" or "long-tailed monkey," reflecting the prominent tails characteristic of the group's members.[7] British zoologist John Edward Gray formally described the tribe Cercopithecini in 1821 within the subfamily Cercopithecinae, initially encompassing guenons (Cercopithecus spp.) and related forms based on morphological features such as cheek pouches and arboreal adaptations.[8] Early 19th-century classifications grouped Cercopithecini broadly with other Old World monkeys under Cercopithecidae, emphasizing dental and cranial similarities, but lacked clear distinctions from other lineages.[9] Throughout the 19th and early 20th centuries, taxonomic shifts occurred as more specimens became available, with revisions incorporating morphological data to refine boundaries; for instance, guenons were distinguished from baboons and macaques by narrower muzzles and more gracile builds.[9] In the mid-20th century, Eric Delson's 1975 synthesis marked a key milestone, formalizing the separation of Cercopithecini from the sister tribe Papionini (including baboons and macaques) based on integrated morphological, paleontological, and zoogeographic evidence, establishing Cercopithecini as a monophyletic group of primarily African, arboreal guenons.[9] Subsequent 20th-century works further delineated genera within the tribe using comparative anatomy, solidifying its distinction from Papionini on traits like tail length and forest-dwelling habits.[8] The advent of molecular data in the 2000s provided robust confirmation of Cercopithecini's monophyly, with studies using retroposons, Y-chromosome markers, and mitochondrial DNA resolving deep divergences and supporting the tribe's integrity against earlier morphology-based uncertainties.[10] For example, analyses of short interspersed elements (SINEs) in 2007 affirmed the clade's African origins and estimated its divergence from Papionini around 11 million years ago, integrating genetic evidence with historical taxonomy.[10]Phylogenetic position
Cercopithecini is a tribe within the subfamily Cercopithecinae of the family Cercopithecidae, which encompasses the Old World monkeys, and is positioned as the sister group to the tribe Papionini, comprising baboons, macaques, and their relatives.[11] This phylogenetic arrangement is supported by extensive molecular data, including analyses of mitochondrial DNA (mtDNA) and nuclear genes, which consistently demonstrate the monophyly of Cercopithecinae and the reciprocal monophyly of its two tribes.[12] The divergence between Cercopithecini and Papionini is estimated to have occurred approximately 11.5 million years ago (Ma), marking a key split within the subfamily during the late Miocene.[11] The tribe's origins trace back to the Miocene epoch (approximately 23–5 Ma) in Africa, where the broader Cercopithecinae subfamily emerged around 17.8 Ma following its divergence from the leaf-eating Colobinae.[11] Molecular clock analyses, calibrated with fossil constraints, indicate that the cercopithecine radiation began in the early to middle Miocene, with Cercopithecini diverging from other cercopithecines around 10–12 Ma.[13] Fossil evidence from this period includes relatives such as Victoriapithecus, an early Miocene cercopithecid dated to about 15–18 Ma from sites in Kenya, which exhibits primitive traits linking it to the basal radiation of Old World monkeys but predates the clear distinction of modern tribes.[14] Within Cercopithecini, phylogenetic reconstructions highlight basal positions for genera like Allenopithecus (swamp monkeys) and Miopithecus (talapoins), which branch off early based on shared derived characters identified through Alu element insertions and Y-chromosome data.[10] These basal lineages likely represent the earliest divergences within the tribe, followed by a major radiation of more derived genera such as Cercopithecus (guenons) and Chlorocebus (vervet monkeys) during the Pliocene (5.3–2.6 Ma), driven by environmental changes in African forests and savannas.[10] This Pliocene diversification is evidenced by molecular phylogenies showing rapid speciation events, with terrestrial adaptations emerging in some lineages around the Miocene-Pliocene boundary.[13]Genera and species
The tribe Cercopithecini encompasses six primary genera, reflecting a diverse radiation of African Old World monkeys primarily adapted to arboreal and semi-terrestrial lifestyles. These include Allenopithecus with a single species, Miopithecus with two species, Erythrocebus with one species, Chlorocebus with six species, Allochrocebus with three species, and the most speciose genus Cercopithecus with approximately 19 species, yielding a total of about 35 extant species across the tribe.[15] This classification follows the taxonomic framework established by Groves in 2001, with subsequent refinements based on molecular and morphological data.[16]- Allenopithecus: Contains one species, Allenopithecus nigroviridis (Allen's swamp monkey), known from swampy habitats in the Congo Basin; no recognized subspecies.[15]
- Miopithecus: Includes two species: Miopithecus talapoin (northern talapoin), distributed in West and Central Africa, and M. ogouensis (southern talapoin), found in the Ogou River region of Gabon; each has limited subspecies variation.[15]
- Erythrocebus: Comprises a single species, Erythrocebus patas (patas monkey), a ground-dwelling form across savannas from West Africa to Sudan; subspecies include E. p. patas, E. p. baumstarki, and E. p. villiersi.[15]
- Chlorocebus: Recognized as six species following its elevation from Cercopithecus in the early 2000s: Chlorocebus pygerythrus (vervet monkey), C. sabaeus (green monkey), C. aethiops (grivet), C. djamdjamensis (Bale Mountains vervet), C. tantalus (Tantalus monkey), and C. cynosuros (malbrouck monkey); several subspecies exist, such as C. p. pygerythrus and C. s. sabaeus, reflecting geographic variation.[15]
- Allochrocebus: Includes three species: Allochrocebus lhoesti (L'Hoest's monkey), A. preussi (Preuss's monkey), and A. solatus (sun-tailed monkey), all terrestrial guenons from Central African forests and mountains.[15]
- Cercopithecus: The largest genus with approximately 19 species, including Cercopithecus ascanius (red-tailed monkey), C. mitis (blue monkey), C. neglectus (De Brazza's monkey), C. cephus (mustached monkey), C. pogonias (crowned monkey), C. mona (mona monkey), C. lowei (Lowe's monkey), C. denti (Dent's mona), C. campbelli (Campbell's mona), C. nictitans (putty-nosed monkey), C. albogularis (Sykes' monkey), C. kandti (golden monkey), C. doggetti (silver monkey), C. diana (Diana monkey), C. roloway (Roloway monkey), C. dryas (Dryas monkey), C. hamlyni (Hamlyn's monkey), C. lomamiensis (lesula), C. wolfi (Wolf's monkey), C. erythrogaster (white-bellied monkey), C. erythrotis (red-eared guenon), and others; many have multiple subspecies, such as C. m. stuhlmanni for the blue monkey complex.[15]