http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2774700/
BMC Evol Biol. 2009; 9: 259.
Published online 2009 October 27. doi: 10.1186/1471-2148-9-259PMCID:
PMC2774700Estimating the phylogeny and divergence times of primates
using a supermatrix approach
To estimate the structure and tempo of primate evolutionary history,
we employed Bayesian phylogenetic methods to analyze data
supermatrices comprising 7 mitochondrial genes (6,138 nucleotides)
from 219 species across 67 genera and 3 nuclear genes (2,157
nucleotides) from 26 genera
Within Primates, the relationships within and between various families
and genera continue to cause debate, despite the numerous molecular
estimates of the phylogeny that have been presented over the past 10
to 15 years
One of the foremost debates in primate systematics has long concerned
the position of tarsiers. Traditionally viewed as being more closely
associated with lemurs and lorises, tarsiers were placed within a
suborder Prosimii, under the gradistic view of primate taxonomy [8].
Modern taxonomic schemes generally recognize their closer affiliation
with monkeys and apes, grouping them with Haplorrhini [9]. The
majority of molecular evidence supports the latter grouping [4,10-13],
although a large number of molecular studies still provide support for
the Prosimii concept [14-18]. The question is succinctly reviewed by
Yoder [19] and is further examined by Eizirik et al. [18]. There is
now general agreement on the higher-level relationships within the two
suborders [20], with Strepsirrhini comprising Lorisiformes (galagos
and lorises) and the sister-pairing of the monophyletic Lemuriformes
(lemurs) and Chiromyiformes (the aye-aye), and with Haplorrhini
consisting of Platyrrhini (New World monkeys) and Catarrhini (apes and
Old World monkeys). Within these groups, however, there are numerous
disagreements over interfamilial relationships. Molecular evidence has
sometimes favored Cheirogaleidae as sister group to Lemuridae,
although current evidence suggests that the four lemuriform families
(Lemuridae, Cheirogaleidae, Lepilemuridae and Indriidae) represent a
four-way split, which may be real or may simply reflect a lack of
resolution [4,21,22]. Within Haplorrhini, controversial taxonomic
issues remain. The paraphyly of an all-encompassing Cebidae with
respect to the tamarins and marmosets is widely recognized now
[9,23,24], but the branching order of the major lineages is still
questionable. Among the Old World monkeys, particularly within
Colobinae, intergeneric relationships are still unclear.
The timescale of primate evolution has also been the subject of
numerous molecular analyses over the past few decades
[4,11,18,20,21,23-32]. Typically, divergence time estimates made using
molecular phylogenetic approaches have supported a much more
protracted timeframe for primate evolution than that suggested by the
fossil record [27,33]. Inferring the age of the most recent common
ancestor of all primates using molecular data has been of particular
interest, owing to the poor understanding of early primate fossils and
the contested affinity of Plesiadapiformes. The oldest unambiguous
primate fossil is dated at 55 million years [34,35], whereas molecular
estimates often place the common primate ancestor in excess of 80
million years ago (MYA) [4,18].