Molecular dating and biogeography of the neritic krill Nyctiphanes
نویسندگان
چکیده
The genus Nyctiphanes (Malacostraca, Euphausiacea) comprises four neritic species that display antitropical geographic distribution in the PaciWc (N. simplex and N. australis) and Atlantic (N. couchii and N. capensis) Oceans. We studied the origin of this distribution applying methods for phylogenetic reconstruction and molecular dating of nodes using a Bayesian MCMC analysis and the DNA sequence information contained in mtDNA 16S rDNA and cytochrome oxidase (COI). We tested hypotheses of vicariance by contrasting the time estimates of cladogenesis with the onset of the major barriers to ocean circulation. It was estimated that Nyctiphanes originated in the PaciWc Ocean during the Miocene, with a lower limit of 18 miilion years ago (Mya). An Atlantic–PaciWc cladogenic event (95% HPD 3.2–9.6) took place after the closure of the Tethyan Sea, suggesting that dispersal occurred from the Indo-PaciWc, most likely via southern Africa. Similarly, the antitropical distribution pattern observed in the eastern Atlantic Ocean likely resulted from recent Pliocene–Pleistocene (95% HPD 1.0–4.97) northward dispersal from the southern hemisphere. Our results imply that dispersal appears to have had a signiWcant role to play in the evolution of this group.
منابع مشابه
Dating divergence of Polystigma and other Sordariomycetes
Studies on the evolutionary history of ascomycetes in terms of time scale will help to understand historical patterns that shape their biodiversity. Until now most of dating studies of ascomycetes have focused on major events in fungal evolution but not on divergence events within smaller groups of fungi e.g. within Sordariomycetes. We used molecular dating to estimate the time of separation of...
متن کاملA Hybrid Data Clustering Algorithm Using Modified Krill Herd Algorithm and K-MEANS
Data clustering is the process of partitioning a set of data objects into meaning clusters or groups. Due to the vast usage of clustering algorithms in many fields, a lot of research is still going on to find the best and efficient clustering algorithm. K-means is simple and easy to implement, but it suffers from initialization of cluster center and hence trapped in local optimum. In this paper...
متن کاملHypothesis testing in biogeography.
Often, biogeography is applied only as a narrative addition to phylogenetic studies and lacks scientific rigour. However, if research questions are framed as hypotheses, biogeographical scenarios become testable. In this review, we explain some problems with narrative biogeography and show how the use of explicit hypotheses is changing understanding of how organisms came to be distributed as th...
متن کاملDetermination of Optimal Capacity and Location of Distributed Generations in Radial Distribution Systems using Krill Herd Algorithm
Abstract Reliability and active power loss are two fundamental parameters in the design and planning of distribution systems that have always attracted the attention of power distribution systems designers and engineers. The improvement of reliability and the reduction of power loss are investigated as the primary objective functions and voltage profile as the secondary objective function. A me...
متن کاملHistorical biogeography of Haloragaceae: an out-of-Australia hypothesis with multiple intercontinental dispersals.
Haloragaceae are a cosmopolitan plant family with its centre of diversity in Australia. Here, we investigate the historical biogeography of the family and the role of vicariance or dispersal in shaping its current distribution. DNA sequences from ITS, matK and the trnK 5' and trnK 3' introns were obtained for 102 species representing all 8 genera of Haloragaceae for use in Bayesian molecular da...
متن کامل