Search results for "Paraphyly"
showing 5 items of 35 documents
New articulated protospongiid sponges from the early Cambrian Chengjiang biota
2015
Sponges are among the earliest diverging crown-group animals and widely regarded as the earliest biomineralizing animals. Indeed, unambiguous hexactine sponge spicules first occur in the lowermost Cambrian strata of the Fortunian Stage. Articulated sponge skeletons interpreted as hexactinellids and demosponges have been reported from Cambrian Stage 2–3 strata at multiple localities. Articulated sponge skeletons in the Chengjiang biota (Cambrian Stage 3), however, are dominated by forms interpreted as demosponges, despite the exceptional preservation in this biota. Here, we report new articulated sponge skeletons from the Chengjiang biota, including Paradiagoniella magna n. gen. n. sp. and P…
Support for the monophyletic origin of Gnathifera from phylogenomics
2009
The monophyletic origin of Spiralia within the metazoan tree of life is supported by many large-scale phylogenomic data. While there is now substantial molecular evidence for Lophotrochozoa being a monophyletic taxon within Spiralia, the phylogenetic affiliations of many other spiralian phyla remain unclear. Here we focus on the question of a monophyletic taxon Gnathifera, which was originally characterized by jaw morphology as comprising the taxa Rotifera, Acanthocephala and Gnathostomulida. Based on a large-scale molecular sequence dataset of 11,146 amino acid residues, we reconstructed phylogenetic trees of spiralian phyla using maximum-likelihood and Bayesian approaches. We obtain the f…
Data from: Megaphylogenetic specimen-level approaches to the Carex (Cyperaceae) phylogeny using ITS, ETS, and matK sequences: implications for classi…
2017
We present the first large-scale phylogenetic hypothesis for the genus Carex based on 996 of the 1983 accepted species (50.23%). We used a supermatrix approach using three DNA regions: ETS, ITS and matK. Every concatenated sequence was derived from a single specimen. The topology of our phylogenetic reconstruction largely agreed with previous studies. We also gained new insights into the early divergence structure of the two largest clades, core Carex and Vignea clades, challenging some previous evolutionary hypotheses about inflorescence structure. Most sections were recovered as non-monophyletic. Homoplasy of characters traditionally selected as relevant for classification, historical mis…
Phylogeny and origin of Jurassic irregular echinoids (Echinodermata: Echinoidea).
2006
27 pages; International audience; A phylogenetic analysis of Jurassic irregular echinoids is realized to explore the origin and early evolution of this important subset of echinoids. The phylogeny is based on 39 characters and considers data from apical system architecture, the corona including tuberculation and spines, Aristotle's lantern, and general test shape. Results corroborate the monophyly of Irregularia, and clarify the phylogenetic interrelationships existing between the main groups of irregular echinoids. Specializations of the Aristotle's lantern, spines, tubercles and phyllodes constitute the apomorphies for different taxa, as for the whole of Irregularia. The phylogenetic sign…
Taxonomic pitfalls in tits - comments on the Paridae chapter of the Handbook of the Birds of the World
2008
In the last two decades, parid systematics and taxonomy have greatly benefited from the consistent application of detailed morphological, bioacoustic and molecular genetic methods. Continuously enlarged character sets, particularly in the latter field, helped to resolve a considerable number of taxonomic controversies, and in some cases a clear grouping of molecular markers (mitochondrial DNA) and vocalizations has enabled unambiguous assignment to taxonomic category. However, in our opinion some of these assignments were inadequately reflected in the species accounts of Handbook of the Birds of the World , vol. 12 (Gosler & Clement 2007). Here we point out what we consider to be major flaw…