Abstract
The concept of climate variability facilitating adaptive radiation supported by the “Court Jester” hypothesis is disputed by the “Red Queen” one, but the prevalence of one or the other might be scale-dependent. We report on a detailed, comprehensive phylo-geographic study on the ∼4 kb mtDNA sequence in underground blind mole rats of the family Spalacidae (or subfamily Spalacinae) from the East Mediterranean steppes. Our study aimed at testing the presence of periodicities in branching patterns on a constructed phylogenetic tree and at searching for congruence between branching events, tectonic history and paleoclimates. In contrast to the strong support for the majority of the branching events on the tree, the absence of support in a few instances indicates that network-like evolution could exist in spalacids. In our tree, robust support was given, in concordance with paleontological data, for the separation of spalacids from muroid rodents during the first half of the Miocene when open, grass-dominated habitats were established. Marine barriers formed between Anatolia and the Balkans could have facilitated the separation of the lineage “Spalax” from the lineage “Nannospalax” and of the clade “leucodon” from the clade “xanthodon”. The separation of the clade “ehrenbergi” occurred during the late stages of the tectonically induced uplift of the Anatolian high plateaus and mountains, whereas the separation of the clade “vasvarii” took place when the rapidly uplifting Taurus mountain range prevented the Mediterranean rainfalls from reaching the Central Anatolian Plateau. The separation of Spalax antiquus and S. graecus occurred when the southeastern Carpathians were uplifted. Despite the role played by tectonic events, branching events that show periodicity corresponding to 400-kyr and 100-kyr eccentricity bands illuminate the important role of orbital fluctuations on adaptive radiation in spalacids. At the given scale, our results supports the “Court Jester” hypothesis over the “Red Queen” one.
Highlights
It has been suggested that the ‘‘Court Jester’’ model [1] which, recognizes the important role of climate change on speciation, and the ‘‘Red Queen’’ model which, promotes biotic over abiotic interactions [2], describe evolution at different time scales [3]
The paleobiological studies indicate that short time scale evolution concerns biotic interactions in ecosystems such as competition, predation, and cooperation, but that large-time scale patterns of biodiversity are driven by the physical environment, including geological and tectonic events, landscape, food supply, or climate [3]
We expect to find that the landscape fluctuations, and the palaeoclimate periodicities and shifts leading to the origin of steppes and/or steppe isolates correspond to branching events in the molecular phylogenetic tree (Figures 1, 2) constructed from samples covering a large part of the blind mole rats distribution (Figure 3)
Summary
It has been suggested that the ‘‘Court Jester’’ model [1] which, recognizes the important role of climate change on speciation, and the ‘‘Red Queen’’ model which, promotes biotic over abiotic interactions [2], describe evolution at different time scales [3]. As all subterranean mammals, display convergent molecular and organismal adaptations to life underground [7] They have been traditionally poor in number of taxa [8]. We expect to find that the landscape fluctuations, and the palaeoclimate periodicities and shifts leading to the origin of steppes and/or steppe isolates correspond to branching events in the molecular phylogenetic tree (Figures 1, 2) constructed from samples covering a large part of the blind mole rats distribution (Figure 3). In spite of the inadequacy of our current methods to capture the complex nature of mtDNA evolution over large time scales, the inferred age estimates support the paleontological data, tectonic and geological events, and the frequency of periodic palaeoclimate changes. At the given scale of resolution, this work supports therfore, the ‘‘Court Jester’’ model [1] over the ‘‘Red Queen’’ one [2]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
