Evolutionary history of the grey-faced Sengi, Rhynchocyon udzungwensis, from Tanzania: a molecular and species distribution modelling approach
- PMID: 24015252
- PMCID: PMC3754996
- DOI: 10.1371/journal.pone.0072506
Evolutionary history of the grey-faced Sengi, Rhynchocyon udzungwensis, from Tanzania: a molecular and species distribution modelling approach
Abstract
Rhynchocyon udzungwensis is a recently described and poorly understood sengi (giant elephant-shrew) endemic to two small montane forests in Southern Tanzania, and surrounded in lower forests by R. cirnei reichardi. In this study, we investigate the molecular genetic relationship between R. udzungwensis and R. c. reichardi, and the possible role that shifting species distributions in response to climate fluctuations may have played in shaping their evolutionary history. Rhynchocyon udzungwensis and R. c. reichardi individuals were sampled from five localities for genetic analyses. Three mitochondrial and two nuclear loci were used to construct species trees for delimitation and to determine whether introgression was detectable either from ancient or ongoing hybridization. All species-tree results show R. udzungwensis and R. c. reichardi as distinct lineages, though mtDNA shows evidence of introgression in some populations. Nuclear loci of each species were monophyletic, implying introgression is exclusively historical. Because we found evidence of introgression, we used distribution data and species distribution modelling for present, glacial, and interglacial climate cycles to predict how shifting species distributions may have facilitated hybridization in some populations. Though interpretations are affected by the limited range of these species, a likely scenario is that the mtDNA introgression found in eastern mid-elevation populations was facilitated by low numbers of R. udzungwensis that expanded into lowland heavily occupied R. c. reichardi areas during interglacial climate cycles. These results imply that relationships within the genus Rhynchocyon may be confounded by porous species boundaries and introgression, even if species are not currently sympatric.
Conflict of interest statement
Figures





References
-
- Mallet J (2005) Hybridization as an invasion of the genome. Trends Ecol Evol 20: 229–237 doi:10.1016/j.tree.2005.02.010 - DOI - PubMed
-
- Rovero F, Rathbun GB, Perkin A, Jones T, Ribble DO, et al. (2008) A new species of giant sengi or elephant-shrew (genus Rhynchocyon) highlights the exceptional biodiversity of the Udzungwa Mountains of Tanzania. J Zool 274: 126–133 doi:10.1111/j.1469-7998.2007.00363.x - DOI
-
- Rathbun GB (2009) Why is there discordant diversity in sengi (Mammalia: Afrotheria: Macroscelidea) taxonomy and ecology? Afr J Ecol 47: 1–13 doi:10.1111/j.1365-2028.2009.01102.x - DOI
-
- Dumbacher JP, Rathbun GB, Smit HA, Eiseb SJ (2012) Phylogeny and Taxonomy of the Round-Eared Sengis or Elephant-Shrews, Genus Macroscelides (Mammalia, Afrotheria, Macroscelidea). PLoS ONE 7: e32410 doi:10.1371/journal.pone.0032410 - DOI - PMC - PubMed
-
- Springer MS, Cleven GC, Madsen O, de Jong WW, Waddell VG, et al. (1997) Endemic African mammals shake the phylogenetic tree. Nature 388: 61–64 doi:10.1038/40386 - DOI - PubMed
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Other Literature Sources