Large rivers do not always act as species barriers for Lepilemur sp.

Abstract

Sportive lemurs constitute a highly diverse endemic lemur family (24 species) for which many biogeographic boundaries are not yet clarified. Based on recent phylogeographic models, this study aims to determine the importance of two large rivers (the Antainambalana and Rantanabe) in northeastern Madagascar as species barriers for Lepilemur seali. The Antainambalana River was previously assumed to act as the southern border of its distribution. A total of 1,038 bp of the mtDNA of four individuals stemming from two adjacent inter-river systems south of the Antainambalana River was sequenced and compared to sequences of 22 described Lepilemur species. The phylogenetic reconstruction did not find support for either of the two rivers as species barrier for Lepilemur, as all captured individuals clustered closely with and therefore belonged to L. seali. However, a previously published sequence of an individual from a site south of our study sites belongs to a separate species. The southern boundary of L. seali must therefore be one of two large rivers further south of our study sites. The results suggest that L. seali may possess a relatively large altitudinal range that enabled this species to migrate around the headwaters of the Antainambalana and Rantanabe Rivers. Previous phylogeographic models need to be refined in order to incorporate these findings, and more species-specific altitudinal range data are urgently needed in order to fully understand the biogeographic patterns of lemurs on Madagascar.

Exceptional diversity of mouse lemurs (Microcebus spp.) in the Makira region with the description of one new species

“…Although we cannot be sure whether the two new species occur north of this river, M. mittermeieri is now confirmed to occur south of it. Similar findings were recently described for the genus Lepilemur [Craul et al, 2008]. L. seali has also been confirmed to occur on both sides of the river.…”

“…L. seali has also been confirmed to occur on both sides of the river. The presence of L. seali on both sides was suggested to be the result of a broad altitudinal range of this species, enabling animals to circumnavigate the headwaters of this large river and to maintain gene flow at least until recent times [Craul et al, 2008; see also Goodman & Ganzhorn, 2004]. The same could in principle apply to Microcebus sp.…”

“…1) where Microcebus mittermeieri occurs [Louis et al, 2006b]. Several large rivers flowing from the eastern mountains into the sea divide the landscape south of this reserve into different Inter-River-Systems (IRSs) [Craul et al, 2008] and could potentially act as species barriers. According to the data available until now, the neighboring species of M. mittermeieri to the south is M. simmonsi, whose northernmost locality (Tampolo) lies more than 250 km south of the Anjanaharibe-South Special Reserve.…”

The genetic population structure of wild western lowland gorillas (Gorilla gorilla gorilla) living in continuous rain forest

“…Studies of great apes found that in chimpanzees ( Pan troglodytes ) [Gonder et al, ] and Bornean orangutans ( Pongo pygmaeus ) [Arora et al, ; Jalil et al, ], rivers apparently act as barriers to individual movement and thereby increase genetic differentiation between subpopulations on either side of the river. No barrier effect of rivers was detected in other smaller‐bodied, more arboreal primates like spider monkeys ( Ateles ) [Collins & Dubach, ], long‐tailed macaques ( Macaca fascicularis ) [Ruiter & Geffen, ] and a number of lemur species (Lemuriformes) [Craul et al, ].…”

Patterns of Water Use in Primates

“…However, the role of river barriers in primate speciation events is controversial. Lemurs in particular have been studied for the effect of rivers on gene flow and speciation, and some studies have claimed that rivers have a large effect [Wilme et al, 2006] while others have found little to no effect [Craul et al, 2008]. More concrete evidence for rivers as cultural barriers does exist, however.…”