Browsing Earth sciences by Types
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The molecularization of centipede systematicsThe injection of molecular data over the past 20 years has impacted on all facets of centipede systematics. Multi-locus and transcriptomic datasets are the source of a novel hypothesis for how the five living orders of centipedes interrelate but force homoplasy in some widely-accepted phenotypic and behavioural characters. Molecular dating is increasingly used to test biogeographic hypotheses, including examples of ancient vicariance. The longstanding challenge of morphological delimitation of centipede species is complemented by integrative taxonomy using molecular tools, including DNA barcoding and coalescent approaches to quantitative species delimitation. Molecular phylogenetics has revealed numerous instances of cryptic species. “Reduced genomic approaches” have the potential to incorporate historic collections, including type specimens, into centipede molecular systematics.
“Perspectives in Animal Phylogeny and Evolution”: A decade laterRefinements in phylogenomic methods and novel data have clarified several controversies in animal phylogeny that were intractable with traditional PCR-based approaches or early Next Gen analyses. An alliance between Placozoa and Cnidaria has recently found support. Data from newly discovered species of Xenoturbella contribute to Xenacoelomorpha being placed as sister group of Nephrozoa rather than within the deuterostomes. Molecular data reinforce the monophyly of Gnathifera and ally the longenigmatic chaetognaths with them. Platyzoa was an artefactual grouping, and deep relationships within Spiralia now depict Rouphozoa (= Gastrotricha + Platyhelminthes) as sister group to Lophotrochozoa, and Gnathifera (plus Chaetognatha) their immediate sister group. A “divide and conquer” strategy of subsampling clades to optimize gene selection may be needed to simultaneously resolve the many disparate clades of the animal tree of life