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.

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Bayesian spatiotemporal diffusion of Tropidurus semitaeniatus complex at 6 time slices. Reconstructions are based on the maximum clade credibility tree estimated with a time-heterogeneous Relaxed Random Walk (RRW) Bayesian phylogeography approach. Shading represents 80%-HPD uncertainty in the location of ancestral branches with lighter and darker shades representing older and younger diffusion events, respectively.
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Fig5: Bayesian spatiotemporal diffusion of Tropidurus semitaeniatus complex at 6 time slices. Reconstructions are based on the maximum clade credibility tree estimated with a time-heterogeneous Relaxed Random Walk (RRW) Bayesian phylogeography approach. Shading represents 80%-HPD uncertainty in the location of ancestral branches with lighter and darker shades representing older and younger diffusion events, respectively.

Mentions: The RRW diffusion model inferred the geographic origin of the T. semitaeniatus species complex at approximately 180 km north of the current course of the SFR, in the limits between Ceará and Paraíba states (latitude: -7.18, longitude: -38.76; Figure 5). The spatiotemporal reconstruction indicates that the T. semitaeniatus species complex diverged at 1.94 Ma (95% HPD: 2.42–1.50) and experienced four main colonization phases: (1) an initial northwestward dispersal with establishment of the ancestors of the northern Ceará and T. jaguaribanus microendemic lineages by 1.15 Ma; (2) two long-distance dispersals towards the south at around 960 ka, with the Uruçui-Una and Serra das Confusões microendemics in one front of colonization into the Parnaíba valley region and the more broadly distributed T. semitaeniatus lineage within close proximity to the SFR in the other front, when the first lineage appeared very close to the current right bank of the river; (3) after traversing the river, T. semitaeniatus split into a lineage alongside the lower course of the present-day SFR and another that underwent a long-distance dispersal towards southern Bahia state; (4) within the last 600 ka, microendemics reached their current distributions and the Northwest T. semitaeniatus lineage dispersed further south bounded by the left border of the SFR, while the southern counterpart spread northwardly until reaching the right margin, expect in Sergipe state where it crossed to the left riverbank (but see Discussion).Figure 5


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)

Bayesian spatiotemporal diffusion of Tropidurus semitaeniatus complex at 6 time slices. Reconstructions are based on the maximum clade credibility tree estimated with a time-heterogeneous Relaxed Random Walk (RRW) Bayesian phylogeography approach. Shading represents 80%-HPD uncertainty in the location of ancestral branches with lighter and darker shades representing older and younger diffusion events, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig5: Bayesian spatiotemporal diffusion of Tropidurus semitaeniatus complex at 6 time slices. Reconstructions are based on the maximum clade credibility tree estimated with a time-heterogeneous Relaxed Random Walk (RRW) Bayesian phylogeography approach. Shading represents 80%-HPD uncertainty in the location of ancestral branches with lighter and darker shades representing older and younger diffusion events, respectively.
Mentions: The RRW diffusion model inferred the geographic origin of the T. semitaeniatus species complex at approximately 180 km north of the current course of the SFR, in the limits between Ceará and Paraíba states (latitude: -7.18, longitude: -38.76; Figure 5). The spatiotemporal reconstruction indicates that the T. semitaeniatus species complex diverged at 1.94 Ma (95% HPD: 2.42–1.50) and experienced four main colonization phases: (1) an initial northwestward dispersal with establishment of the ancestors of the northern Ceará and T. jaguaribanus microendemic lineages by 1.15 Ma; (2) two long-distance dispersals towards the south at around 960 ka, with the Uruçui-Una and Serra das Confusões microendemics in one front of colonization into the Parnaíba valley region and the more broadly distributed T. semitaeniatus lineage within close proximity to the SFR in the other front, when the first lineage appeared very close to the current right bank of the river; (3) after traversing the river, T. semitaeniatus split into a lineage alongside the lower course of the present-day SFR and another that underwent a long-distance dispersal towards southern Bahia state; (4) within the last 600 ka, microendemics reached their current distributions and the Northwest T. semitaeniatus lineage dispersed further south bounded by the left border of the SFR, while the southern counterpart spread northwardly until reaching the right margin, expect in Sergipe state where it crossed to the left riverbank (but see Discussion).Figure 5

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