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Morphological Data Set (morphological + data_set)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

On bivalve phylogeny: a high-level analysis of the Bivalvia (Mollusca) based on combined morphology and DNA sequence data

INVERTEBRATE BIOLOGY, Issue 4 2002
Gonzalo Giribet
Abstract. Bivalve classification has suffered in the past from the crossed-purpose discussions among paleontologists and neontologists, and many have based their proposals on single character systems. More recently, molecular biologists have investigated bivalve relationships by using only gene sequence data, ignoring paleontological and neontological data. In the present study we have compiled morphological and anatomical data with mostly new molecular evidence to provide a more stable and robust phylogenetic estimate for bivalve molluscs. The data here compiled consist of a morphological data set of 183 characters, and a molecular data set from 3 loci: 2 nuclear ribosomal genes (18S rRNA and 28S rRNA), and 1 mitochondrial coding gene (cytochrome c oxidase subunit I), totaling ,3 Kb of sequence data for 76 molluscs (62 bivalves and 14 outgroup taxa). The data have been analyzed separately and in combination by using the direct optimization method of Wheeler (1996), and they have been evaluated under 12 analytical schemes. The combined analysis supports the monophyly of bivalves, paraphyly of protobranchiate bivalves, and monophyly of Autolamellibranchiata, Pteriomorphia, Heteroconchia, Palaeoheterodonta, and Heterodonta s.l., which includes the monophyletic taxon Anomalodesmata. These analyses strongly support the conclusion that Anomalodesmata should not receive a class status, and that the heterodont orders Myoida and Veneroida are not monophyletic. Among the most stable results of the analysis are the monophyly of Palaeoheterodonta, grouping the extant trigoniids with the freshwater unionids, and the sister-group relationship of the heterodont families Astartidae and Carditidae, which together constitute the sister taxon to the remaining heterodont bivalves. Internal relationships of the main bivalve groups are discussed on the basis of node support and clade stability. [source]

Phylogeny and the modalities of acoustic diversification in extant Eneopterinae (Insecta, Orthoptera, Grylloidea, Eneopteridae)

CLADISTICS, Issue 3 2004
Tony Robillard
Calling with a tegminal stridulatory apparatus is widespread in crickets. However, the evolution of cricket stridulums has been poorly studied and then only on the basis of prephylogenetic models, which are unable to account for the huge diversity recently documented for acoustic features in crickets. The present paper focuses on the evolution of acoustic devices in the subfamily Eneopterinae. This is the first attempt to reconstruct the phylogeny of a large and diverse cricket clade in order to analyze the evolution of emitting structures using precise homology statements. In the first step, we reconstruct the phylogeny of this clade using a morphological data set of 193 characters and 45 taxa. The resultant phylogeny supports the monophyly of the subfamily and that of the 13 genera represented by at least two species in our taxonomic sample. Phylogenetic relationships within the subfamily also support the definition of five tribes: Eurepini, Eneopterini, Nisitrini, Xenogryllini and Lebinthini. In the second step, the evolution of acoustic devices is studied by optimization of venation characters defined on precise homology statements. As hypothesized by previous authors, losses of acoustic communication occur independently in the course of eneopterine evolution; however, they happen abruptly with no intermediate state. Our results also document for the first time the modalities of forewing evolution: the diversification of male forewing venation originates from two processes, a continuous and regular modification process, responsible for slight venation change; and an irregular, more intense punctuated process, allowing the emergence of different venations. This diversification process with sudden changes could be related to the occurrence of acoustic novelties in advertisement calls. [source]

Morphology versus molecules: resolution of the positions of Nymphalis, Polygonia, and related genera (Lepidoptera: Nymphalidae)

CLADISTICS, Issue 3 2003
Niklas Wahlberg
The debate on whether to combine different data sets for simultaneous analysis has continued to the present day unabated. We have studied the effects of combining one morphological data set with four molecular data sets (two mitochondrial gene sequences and two nuclear gene sequences) for a group of butterflies belonging to the tribe Nymphalini using partitioned Bremer support. We particularly focus our attention on a group of species belonging to the genera Aglais, Inachis, Roddia, Nymphalis, Kaniska, and Polygonia. We find that, despite significant incongruence between most data partitions, all data partitions contribute positively to the support of most nodes in the most parsimonious trees found for the combined data set. We also find that the morphological data set resolves one particular node (Kaniska basal to Polygonia) with good support, while the molecular data sets are ambiguous about the existence of this node. We suggest that partitioned Bremer support allows one to critically appraise the robustness of each node in a given tree and thereby identify nodes that may change with the addition of new data and nodes that are likely to remain unchanged with new data. We also suggest that morphological data are still crucial to our being able to understand the relationships of extant organisms, despite published views to the contrary. Based on our results we suggest that Inachis should be synonymized with Aglais, Roddia with Nymphalis, and Kaniska with Polygonia. [source]

Bahiaxenidae, a "living fossil" and a new family of Strepsiptera (Hexapoda) discovered in Brazil

CLADISTICS, Issue 6 2009
Freddy Bravo
An adult male of a newly discovered strepsipteran species from Brazil,Bahiaxenos relictus,is described. A new family Bahiaxenidae is suggested based on cladistic analyses of comprehensive morphological data sets with a broad taxon sampling including the stem group. It is unambiguously placed as the sister group of all other extant families of Strepsiptera. Bahiaxenos relictus is the only species of basal, i.e. non-stylopidian, Strepsiptera occurring in the New World. It appears to be a relict taxon that has survived in the fossil sand dunes of the São Francisco River (Bahia State). The loss of the 8th antennomere and the greatly reduced labrum are autapomorphies of Strepsiptera s.s. excluding Bahiaxenidae. The sister group relationship between,Protoxenidae and the remaining Strepsiptera, and between ,Cretostylops and a clade comprising ,Mengea and Strepsiptera s.s., is confirmed, as is the monophyly of Stylopidia and Stylopiformia. [source]