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Evolution underground: shedding light on the diversification of subterranean insects.

Juan C, Emerson BC - J. Biol. (2010)

Bottom Line: A recent study in BMC Evolutionary Biology has reconstructed the molecular phylogeny of a large Mediterranean cave-dwelling beetle clade, revealing an ancient origin and strong geographic structuring.It seems likely that diversification of this clade in the Oligocene was seeded by an ancestor already adapted to subterranean life.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department de Biologia, Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain. cjuan@uib.es

ABSTRACT
A recent study in BMC Evolutionary Biology has reconstructed the molecular phylogeny of a large Mediterranean cave-dwelling beetle clade, revealing an ancient origin and strong geographic structuring. It seems likely that diversification of this clade in the Oligocene was seeded by an ancestor already adapted to subterranean life.

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Cave-beetles and phylogenies. (a) Photograph of the cave-beetle species Cytodromus dapsoides (Leptoridini, Leiodidae) from the Vercors National Park in Southeast France. The tribe Leptodirini includes about 235 genera and around 900 species, most of them exclusively subterranean. The highest diversity is found in the north and east of the Iberian Peninsula, Corsica and Sardinia, the southern Alps, Balkan Peninsula, Romania and southern Russia, the Caucasus, Middle East and Iran. (b) Simplified phylogenetic tree obtained by Ribera et al. [5] using combined mitochondrial and nuclear sequences. The tree was linearized (fitted to constancy of molecular substitution rate) using Bayesian methods. Red circles indicate tree nodes used for calibration of the molecular clock using the mitochondrial gene cox1 only (considering 33 million years ago for the age of initial separation of Sardinian species from their sister lineage), and including all mitochondrial sequence information but excluding species from Sardinia (from which only cox1 sequences were available). In the latter case an estimated age of 37.8 million years ago was used for the separation of Bathysciola zariquieyi from its sister. The width of each clade is proportional to the number of species included in the study. The basal Speonomidius lineage includes the muscicolus genus Notidocharis. A geological timeline with the relevant epochs is provided below the tree. Figure 1a courtesy of Christian Vanderbergh.
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Figure 1: Cave-beetles and phylogenies. (a) Photograph of the cave-beetle species Cytodromus dapsoides (Leptoridini, Leiodidae) from the Vercors National Park in Southeast France. The tribe Leptodirini includes about 235 genera and around 900 species, most of them exclusively subterranean. The highest diversity is found in the north and east of the Iberian Peninsula, Corsica and Sardinia, the southern Alps, Balkan Peninsula, Romania and southern Russia, the Caucasus, Middle East and Iran. (b) Simplified phylogenetic tree obtained by Ribera et al. [5] using combined mitochondrial and nuclear sequences. The tree was linearized (fitted to constancy of molecular substitution rate) using Bayesian methods. Red circles indicate tree nodes used for calibration of the molecular clock using the mitochondrial gene cox1 only (considering 33 million years ago for the age of initial separation of Sardinian species from their sister lineage), and including all mitochondrial sequence information but excluding species from Sardinia (from which only cox1 sequences were available). In the latter case an estimated age of 37.8 million years ago was used for the separation of Bathysciola zariquieyi from its sister. The width of each clade is proportional to the number of species included in the study. The basal Speonomidius lineage includes the muscicolus genus Notidocharis. A geological timeline with the relevant epochs is provided below the tree. Figure 1a courtesy of Christian Vanderbergh.

Mentions: Testing hypotheses of origin and adaptation among subterranean taxa has been hindered by the inherent difficulties of sampling the rare and more elusive cave taxa and extensive morphological convergence caused by strong selection pressures imposed by the subterranean environment [4]. In recent years molecular phylogenies have been obtained for numerous taxonomic groups containing subterranean lineages, permitting rigorous comparisons of competing evolutionary hypotheses. In a study published in BMC Evolutionary Biology, Ribera et al. [5] have investigated the origin and evolution of a diverse lineage of subterranean beetles of the tribe Leptodirini (family Leiodidae) (Figure 1a), focusing on the distribution of this group in the western Mediterranean. This study is one of the first in which the evolutionary history of a presumably monophyletic group composed of mostly subterranean species is examined using molecular data. Samples of a large number of species from genera occurring in the Iberian Peninsula plus representatives from Sardinia and the Carpathians are included in the study. DNA sequences totalling 4 kilobases from five mitochondrial and two nuclear DNA fragments were used to construct robust phylogenies using different methods and to quantify diversification patterns and times from molecular clock calibrations.


Evolution underground: shedding light on the diversification of subterranean insects.

Juan C, Emerson BC - J. Biol. (2010)

Cave-beetles and phylogenies. (a) Photograph of the cave-beetle species Cytodromus dapsoides (Leptoridini, Leiodidae) from the Vercors National Park in Southeast France. The tribe Leptodirini includes about 235 genera and around 900 species, most of them exclusively subterranean. The highest diversity is found in the north and east of the Iberian Peninsula, Corsica and Sardinia, the southern Alps, Balkan Peninsula, Romania and southern Russia, the Caucasus, Middle East and Iran. (b) Simplified phylogenetic tree obtained by Ribera et al. [5] using combined mitochondrial and nuclear sequences. The tree was linearized (fitted to constancy of molecular substitution rate) using Bayesian methods. Red circles indicate tree nodes used for calibration of the molecular clock using the mitochondrial gene cox1 only (considering 33 million years ago for the age of initial separation of Sardinian species from their sister lineage), and including all mitochondrial sequence information but excluding species from Sardinia (from which only cox1 sequences were available). In the latter case an estimated age of 37.8 million years ago was used for the separation of Bathysciola zariquieyi from its sister. The width of each clade is proportional to the number of species included in the study. The basal Speonomidius lineage includes the muscicolus genus Notidocharis. A geological timeline with the relevant epochs is provided below the tree. Figure 1a courtesy of Christian Vanderbergh.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2871511&req=5

Figure 1: Cave-beetles and phylogenies. (a) Photograph of the cave-beetle species Cytodromus dapsoides (Leptoridini, Leiodidae) from the Vercors National Park in Southeast France. The tribe Leptodirini includes about 235 genera and around 900 species, most of them exclusively subterranean. The highest diversity is found in the north and east of the Iberian Peninsula, Corsica and Sardinia, the southern Alps, Balkan Peninsula, Romania and southern Russia, the Caucasus, Middle East and Iran. (b) Simplified phylogenetic tree obtained by Ribera et al. [5] using combined mitochondrial and nuclear sequences. The tree was linearized (fitted to constancy of molecular substitution rate) using Bayesian methods. Red circles indicate tree nodes used for calibration of the molecular clock using the mitochondrial gene cox1 only (considering 33 million years ago for the age of initial separation of Sardinian species from their sister lineage), and including all mitochondrial sequence information but excluding species from Sardinia (from which only cox1 sequences were available). In the latter case an estimated age of 37.8 million years ago was used for the separation of Bathysciola zariquieyi from its sister. The width of each clade is proportional to the number of species included in the study. The basal Speonomidius lineage includes the muscicolus genus Notidocharis. A geological timeline with the relevant epochs is provided below the tree. Figure 1a courtesy of Christian Vanderbergh.
Mentions: Testing hypotheses of origin and adaptation among subterranean taxa has been hindered by the inherent difficulties of sampling the rare and more elusive cave taxa and extensive morphological convergence caused by strong selection pressures imposed by the subterranean environment [4]. In recent years molecular phylogenies have been obtained for numerous taxonomic groups containing subterranean lineages, permitting rigorous comparisons of competing evolutionary hypotheses. In a study published in BMC Evolutionary Biology, Ribera et al. [5] have investigated the origin and evolution of a diverse lineage of subterranean beetles of the tribe Leptodirini (family Leiodidae) (Figure 1a), focusing on the distribution of this group in the western Mediterranean. This study is one of the first in which the evolutionary history of a presumably monophyletic group composed of mostly subterranean species is examined using molecular data. Samples of a large number of species from genera occurring in the Iberian Peninsula plus representatives from Sardinia and the Carpathians are included in the study. DNA sequences totalling 4 kilobases from five mitochondrial and two nuclear DNA fragments were used to construct robust phylogenies using different methods and to quantify diversification patterns and times from molecular clock calibrations.

Bottom Line: A recent study in BMC Evolutionary Biology has reconstructed the molecular phylogeny of a large Mediterranean cave-dwelling beetle clade, revealing an ancient origin and strong geographic structuring.It seems likely that diversification of this clade in the Oligocene was seeded by an ancestor already adapted to subterranean life.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department de Biologia, Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain. cjuan@uib.es

ABSTRACT
A recent study in BMC Evolutionary Biology has reconstructed the molecular phylogeny of a large Mediterranean cave-dwelling beetle clade, revealing an ancient origin and strong geographic structuring. It seems likely that diversification of this clade in the Oligocene was seeded by an ancestor already adapted to subterranean life.

Show MeSH
Related in: MedlinePlus