Search results for "vicariance"
showing 10 items of 40 documents
Overlooked cryptic endemism in copepods: Systematics and natural history of the calanoid subgenus Occidodiaptomus Borutzky 1991 (Copepoda, Calanoida,…
2012
Abstract Our comprehension of the phylogeny and diversity of most inland–water crustaceans is currently hampered by their pronounced morphological bradytely, which contributed to the affirmation of the “Cosmopolitanism Paradigm” of freshwater taxa. However, growing evidence of the existence of cryptic diversity and molecular regionalism is available for calanoid copepods, thus stressing the need for careful morphological and molecular studies in order to soundly investigate the systematics, diversity and distribution patterns of the group. Diaptomid copepods were here chosen as model taxa, and the morphological and molecular diversity of the species belonging to the west-Mediterranean diapt…
Nuclear and chloroplast DNA variation in Cephalaria squamiflora (Dipsacaceae), a disjunct Mediterranean species
2009
Cephalaria squamiflora is a chamaephyte restricted to rupicolous habitats in islands of the Western (Balearic Islands, Sardinia) and Eastern Mediterranean (Crete and few Aegean islands). Four narrowly distributed races (subspp. squamiflora, mediterranea, ebusitana, balearica) have been described to encompass the morphological variation within the species. We have used nuclear ribosomal ITS and cpDNA sequences to assess how the patterns of molecular differentiation are related to taxonomic and geographic boundaries. Extensive intragenomic ITS variation was detected in samples from all territories, the average sequence divergence among cloned ribotypes was 1.339%. The parsimony network of clo…
Phylogenetic analysis informed by geological history supports multiple, sequential invasions of the Mediterranean Basin by the angiosperm family Arac…
2008
Despite the remarkable species richness of the Mediterranean flora and its well-known geological history, few studies have investigated its temporal and spatial origins. Most importantly, the relative contribution of geological processes and long-distance dispersal to the composition of contemporary Mediterranean biotas remains largely unknown. We used phylogenetic analyses of sequences from six chloroplast DNA markers, Bayesian dating methods, and ancestral area reconstructions, in combination with paleogeographic, paleoclimatic, and ecological evidence, to elucidate the time frame and biogeographic events associated with the diversification of Araceae in the Mediterranean Basin. We focuse…
Palaeoclimatic changes explain Anatolian mountain frog evolution: a test for alternating vicariance and dispersal events
2002
Holarctic biodiversity has been influenced by climatic fluctuations since the Pliocene. Asia Minor was one of the major corridors for postglacial invasions in the Palearctic. Today this area is characterized by an extraordinarily rich fauna with close affiliation to European, Asian and Indo-African biota. However, exact scenarios of range expansion and contraction are lacking. Using a phylogeographical approach we (i) identify monophyletic lineages among Anatolian mountain frogs and (ii) derive a spatio-temporal hypothesis for the invasion process in Anatolia. We sequenced 540 bp of the mitochondrial 16S rRNA gene from 40 populations of mountain frogs from Anatolia, the Elburz Mountains and…
Multiple overseas dispersal in amphibians
2003
Amphibians are thought to be unable to disperse over ocean barriers because they do not tolerate the osmotic stress of salt water. Their distribution patterns have therefore generally been explained by vicariance biogeography. Here, we present compelling evidence for overseas dispersal of frogs in the Indian Ocean region based on the discovery of two endemic species on Mayotte. This island belongs to the Comoro archipelago, which is entirely volcanic and surrounded by sea depths of more than 3500 m. This constitutes the first observation of endemic amphibians on oceanic islands that did not have any past physical contact to other land masses. The two species of frogs had previously been tho…
A taxonomic revision of the Capparis spinosa group (Capparaceae) from eastern Africa to Oceania
2015
The variability, autecology and distribution of the Capparis spinosa group have been studied in eastern Africa, Madagascar, southern Asia, Australia and Oceania. In these areas the taxonomic treatment of the group, also represented in holoarctic Regions of the Old World, is still critical. The forms widespread in the study area are here referred to four subspecies of C. spinosa . The recognized subspecies mostly show geographical vicariance, except in some contact areas of the Middle East and western Himalaya. Two nomenclatural novelties, i. e. C. spinosa subsp. cordifolia comb. et stat. nov. and C. spinosa subsp. himalayensis stat. nov., are proposed. Among the recognized taxa, C. spinosa …
A Multidisciplinary Approach to the Analysis of Multifactorial Land Mammal Colonization of Islands
2013
A highly debated question that engages paleontologists, zoogeographers, and zoologists is how terrestrial mammals colonize islands. The question’s oversimplification and the subjective and partial responses to it have led to reductionist models. Insular faunas and fossil assemblages result from a complex interaction of geological, biological (in a broad sense), climatic, eustatic, taphonomic, and historical processes. Insular assemblages and their accompanying variables should be investigated on a case-by-case basis. In this article, we discuss not only common misconceptions and their potential origins but also the key issues that should be addressed when dealing with the colonization of is…
Cracking the nut: Geographical adjacency of sister taxa supports vicariance in a polytomic salamander clade in the absence of node support
2008
The urodelan genus Lyciasalamandra, which inhabits a relatively small area along the southern Turkish coast and some Aegean islands, provides an outstanding example of a diverse but phylogenetically unresolved taxon. Molecular trees contain a single basal polytomy that could be either soft or hard. We here use the information of nuclear (allozymes) and mitochondrial (fractions of the 16S rRNA and ATPase genes) datasets in combination with area relationships of lineages to resolve the phylogenetic relationships among Lyciasalamandra species in the absence of sufficient node support. We can show that neither random processes nor introgressive hybridization can be invoked to explain that the m…
Climatic oscillations triggered post-Messinian speciation of Western Palearctic brown frogs (Amphibia, Anura, Ranidae)
2003
Abstract Oscillating glacial cycles over the past 2.4 million years are proposed to have had a major impact on the diversity of contemporary species communities. We used mitochondrial and nuclear DNA sequence data to infer phylogenetic relationships within Western Palearctic brown frogs and to test the influence of Pliocene and Pleistocene climatic changes on their evolution. We sequenced 1976 bp of the mitochondrial genes 16S rRNA and cytochrome b and of the nuclear rhodopsin gene for all current species and subspecies. Based on an established allozyme clock for Western Palearctic water frogs and substitution rate constancy among water frogs and brown frogs, we calibrated a molecular clock…
From Europe to Africa and vice versa: evidence for multiple intercontinental dispersal in ribbed salamanders (Genus Pleurodeles)
2004
Aim The intricate puzzle-like geography of the western Mediterranean is a product of long-term tectonic and orogenic events, supplemented by repeated climatic oscillations since the Pliocene. It offers numerous vicariance events that may be invoked to explain speciation in amphibians. We test for plausibility of two mutually exclusive Iberian–African vicariance hypotheses to explain the basal split within newts of the genus Pleurodeles: (1) the disconnection of the Betic arch c. 14 Ma and (2) the end of the Messinian salinity crisis 5.33 Ma. Location Specimens of P. waltl and P. poireti were sampled from 32 populations in Portugal, Spain, Morocco, Algeria and Tunisia. Methods Parts of th…