Limits...
Biogeographic history and cryptic diversity of saxicolous Tropiduridae lizards endemic to the semiarid Caatinga.

Werneck FP, Leite RN, Geurgas SR, Rodrigues MT - BMC Evol. Biol. (2015)

Bottom Line: The phylogenetic and population structures are intrinsically associated with stable rock surfaces and landscape rearrangements, such as the establishment of drainage basins located to the northern and southern distribution ranges.The T. semitaeniatus complex preserved high genetic diversity during range expansion, possibly as a result of frequent long-distance dispersal events.Our results indicate that both the current course of the São Francisco River and its paleo-courses had an important role in promoting diversification of the Caatinga endemic T. semitaeniatus species group.

View Article: PubMed Central - PubMed

Affiliation: Programa de Coleções Científicas Biológicas, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo 2936, 69060-000, Manaus, AM, Brazil. fewerneck@gmail.com.

ABSTRACT

Background: Phylogeographic research has advanced in South America, with increasing efforts on taxa from the dry diagonal biomes. However, the diversification of endemic fauna from the semiarid Caatinga biome in northeastern Brazil is still poorly known. Here we targeted saxicolous lizards of the Tropidurus semitaeniatus species group to better understand the evolutionary history of these endemic taxa and the Caatinga. We estimated a time-calibrated phylogeny for the species group based on two mitochondrial and two nuclear genes and jointly estimated the species limits and species tree within the group. We also devoted a denser phylogeographic sampling of the T. semitaeniatus complex to explore migration patterns, and the spatiotemporal diffusion history to verify a possible role of the São Francisco River as a promoter of differentiation in this saxicolous group of lizards.

Results: Phylogenetic analysis detected high cryptic genetic diversity, occurrence of unique microendemic lineages associated with older highlands, and a speciation history that took place during the Pliocene-Pleistocene transition. Species delimitation detected five evolutionary entities within the T. semitaeniatus species group, albeit with low support. Thus, additional data are needed for a more accurate definition of species limits and interspecific relationships within this group. Spatiotemporal analyses reconstructed the geographic origin of the T. semitaeniatus species complex to be located north of the present-day course of the São Francisco River, followed by dispersal that expanded its distribution towards the northwest and south. Gene flow estimates showed higher migration rates into the lineages located north of the São Francisco River.

Conclusions: The phylogenetic and population structures are intrinsically associated with stable rock surfaces and landscape rearrangements, such as the establishment of drainage basins located to the northern and southern distribution ranges. The T. semitaeniatus complex preserved high genetic diversity during range expansion, possibly as a result of frequent long-distance dispersal events. Our results indicate that both the current course of the São Francisco River and its paleo-courses had an important role in promoting diversification of the Caatinga endemic T. semitaeniatus species group.

Show MeSH
Species tree and divergence times for the Tropidurus semitaeniatus species group and outgroups based on the more inclusive species assignments from GMYC. The maximum clade credibility tree was inferred under a coalescent model based on all three independent loci with *BEAST. Posterior probability (pp) values are indicated by colored circles in the node colors; nodes with no indicative of support have pp < 0.75.
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Fig4: Species tree and divergence times for the Tropidurus semitaeniatus species group and outgroups based on the more inclusive species assignments from GMYC. The maximum clade credibility tree was inferred under a coalescent model based on all three independent loci with *BEAST. Posterior probability (pp) values are indicated by colored circles in the node colors; nodes with no indicative of support have pp < 0.75.

Mentions: The species tree estimation using the assignment of mtDNA haploclades recovered interspecific relationships that are similar to those on the mtDNA gene tree, except for the placement of Seridó microendemics as sister to the three broadly distributed lineages comprising Clade C, albeit with low nodal support (Additional file 1: Figure S3). Alternatively, the species tree based on the assignment of genetic lineages detected by the GMYC species delimitation had higher support for all nodes and was favored by a Bayes factor (logBayes = 37.79) indicating strong support for the latter hypothesis. In this species tree, Tropidurus pinima is sister to a clade containing all other taxa in the species group, including T. helenae nested within the T. semitaeniatus species complex (Figure 4). However, the position of T. helenae was weakly supported. This suggests that although the species tree may recover the main relationships, some degree of topological uncertainty still remains, specially with respect to T. helenae, and additional markers would be required to solve this matter.Figure 4


Biogeographic history and cryptic diversity of saxicolous Tropiduridae lizards endemic to the semiarid Caatinga.

Werneck FP, Leite RN, Geurgas SR, Rodrigues MT - BMC Evol. Biol. (2015)

Species tree and divergence times for the Tropidurus semitaeniatus species group and outgroups based on the more inclusive species assignments from GMYC. The maximum clade credibility tree was inferred under a coalescent model based on all three independent loci with *BEAST. Posterior probability (pp) values are indicated by colored circles in the node colors; nodes with no indicative of support have pp < 0.75.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4494643&req=5

Fig4: Species tree and divergence times for the Tropidurus semitaeniatus species group and outgroups based on the more inclusive species assignments from GMYC. The maximum clade credibility tree was inferred under a coalescent model based on all three independent loci with *BEAST. Posterior probability (pp) values are indicated by colored circles in the node colors; nodes with no indicative of support have pp < 0.75.
Mentions: The species tree estimation using the assignment of mtDNA haploclades recovered interspecific relationships that are similar to those on the mtDNA gene tree, except for the placement of Seridó microendemics as sister to the three broadly distributed lineages comprising Clade C, albeit with low nodal support (Additional file 1: Figure S3). Alternatively, the species tree based on the assignment of genetic lineages detected by the GMYC species delimitation had higher support for all nodes and was favored by a Bayes factor (logBayes = 37.79) indicating strong support for the latter hypothesis. In this species tree, Tropidurus pinima is sister to a clade containing all other taxa in the species group, including T. helenae nested within the T. semitaeniatus species complex (Figure 4). However, the position of T. helenae was weakly supported. This suggests that although the species tree may recover the main relationships, some degree of topological uncertainty still remains, specially with respect to T. helenae, and additional markers would be required to solve this matter.Figure 4

Bottom Line: The phylogenetic and population structures are intrinsically associated with stable rock surfaces and landscape rearrangements, such as the establishment of drainage basins located to the northern and southern distribution ranges.The T. semitaeniatus complex preserved high genetic diversity during range expansion, possibly as a result of frequent long-distance dispersal events.Our results indicate that both the current course of the São Francisco River and its paleo-courses had an important role in promoting diversification of the Caatinga endemic T. semitaeniatus species group.

View Article: PubMed Central - PubMed

Affiliation: Programa de Coleções Científicas Biológicas, Instituto Nacional de Pesquisas da Amazônia, Av. André Araújo 2936, 69060-000, Manaus, AM, Brazil. fewerneck@gmail.com.

ABSTRACT

Background: Phylogeographic research has advanced in South America, with increasing efforts on taxa from the dry diagonal biomes. However, the diversification of endemic fauna from the semiarid Caatinga biome in northeastern Brazil is still poorly known. Here we targeted saxicolous lizards of the Tropidurus semitaeniatus species group to better understand the evolutionary history of these endemic taxa and the Caatinga. We estimated a time-calibrated phylogeny for the species group based on two mitochondrial and two nuclear genes and jointly estimated the species limits and species tree within the group. We also devoted a denser phylogeographic sampling of the T. semitaeniatus complex to explore migration patterns, and the spatiotemporal diffusion history to verify a possible role of the São Francisco River as a promoter of differentiation in this saxicolous group of lizards.

Results: Phylogenetic analysis detected high cryptic genetic diversity, occurrence of unique microendemic lineages associated with older highlands, and a speciation history that took place during the Pliocene-Pleistocene transition. Species delimitation detected five evolutionary entities within the T. semitaeniatus species group, albeit with low support. Thus, additional data are needed for a more accurate definition of species limits and interspecific relationships within this group. Spatiotemporal analyses reconstructed the geographic origin of the T. semitaeniatus species complex to be located north of the present-day course of the São Francisco River, followed by dispersal that expanded its distribution towards the northwest and south. Gene flow estimates showed higher migration rates into the lineages located north of the São Francisco River.

Conclusions: The phylogenetic and population structures are intrinsically associated with stable rock surfaces and landscape rearrangements, such as the establishment of drainage basins located to the northern and southern distribution ranges. The T. semitaeniatus complex preserved high genetic diversity during range expansion, possibly as a result of frequent long-distance dispersal events. Our results indicate that both the current course of the São Francisco River and its paleo-courses had an important role in promoting diversification of the Caatinga endemic T. semitaeniatus species group.

Show MeSH