Uncertainty Regarding Species Delimitation, Geographic Distribution, and the Evolutionary History of South-Central Amazonian Titi Monkey Species (Plecturocebus, Pitheciidae)

• Published in: International journal of primatology Vol. 45; no. 1; pp. 12 - 34
• Main Authors: Byrne, Hazel, Costa-Araújo, Rodrigo, Farias, Izeni P., da Silva, Maria N. F., Messias, Mariluce, Hrbek, Tomas, Boubli, Jean P.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-02-2024; Springer Nature B.V
• Subjects: Affinity; Animal Ecology; Animal Genetics and Genomics; Anthropology; Bayesian analysis; Biomedical and Life Sciences; Bleaching; Classification; Evolution; Evolutionary Biology; Geographic distribution; Geographical distribution; Haplotypes; Human Genetics; Hybridization; Life Sciences; Locality; Monkeys; New species; North and South; Pelage; Phylogeny; Pigmentation; Primates; Questions; Taxa; Taxonomy; Uncertainty; Zoology; Introgression; Phylogenetic conflict; Morphological cline
• ISSN: 0164-0291; 1573-8604
• DOI: 10.1007/s10764-021-00249-9

Platyrrhine primate taxonomy is a rapidly evolving area of research. The recent description of the Parecis titi monkey,
Plecturocebus parecis
, has raised substantial questions regarding the taxonomy, distribution, and evolutionary history of titi taxa from south-central Amazonia. There is only a single documented record of
P. parecis
, which is the type locality, with uncertainty regarding species monophyly. Moreover, there are questions surrounding the distribution and pelage patterns of the poorly studied
P. cinerascens
and
P. parecis
, which further highlight the uncertainty regarding the taxonomic validity of this new species. Here, we investigate the taxonomy, distribution, and evolutionary history of these lineages through new field work and assessment of pelage pigmentation patterns from 25 localities, as well as maximum likelihood and Bayesian phylogenetic reconstructions based on two mitochondrial and 11 nuclear loci for 19 and 10 specimens of
Plecturocebus
, respectively. Our mitochondrial results recover a paraphyletic arrangement for the four
P. parecis
type specimens that show three distinct haplotypes, with the holotype showing a close affinity to
P. bernhardi
. Our morphological analysis reveals a north–south clinal bleaching gradient through the Aripuanã-Sucundurí/Juruena interfluve from an all-grayish morphotype associated with
P. cinerascens
, through intermediary morphotypes with increasingly whitish hairs on the beard, hands, feet, and tail, to the most whitish morphotype described as
P. parecis
. Based on these findings, we present hypotheses to explain the taxonomy, distribution, and evolutionary history of
P. cinerascens
and
P. parecis
and discuss the significance of introgression among titi taxa from southern Amazonia given the lack of study systems for natural hybridization in platyrrhine primates.