Ingroup relationships of Lagerpetidae (Avemetatarsalia: Dinosauromorpha): a further phylogenetic investigation on the understanding of dinosaur relatives

Zootaxa ◽  
2018 ◽  
Vol 4392 (1) ◽  
pp. 149 ◽  
Author(s):  
RODRIGO TEMP MÜLLER ◽  
MAX CARDOSO LANGER ◽  
SÉRGIO DIAS-DA-SILVA

Despite representing a key-taxon in dinosauromorph phylogeny, Lagerpertidae is one of the most obscure and enigmatic branches from the stem that leads to the dinosaurs. Recent new findings have greatly increased our knowledge about lagerpetids, but no phylogenetic analysis has so far included all known members of this group. Here, we present the most inclusive phylogenetic study so far conducted for Lagerpetidae. Phylogenetic analyses were performed based on three independent data matrixes. In two of them, Lagerpeton chanarensis Romer, 1971 is the sister taxon to all other known Lagerpetidae, whereas Ixalerpeton polesinensis Cabreira et al., 2016 is in a sister group relationship with a clade that includes PVSJ 883 and Dromomeron. Conversely, the other analysis supports an alternative topology, where I. polesinensis is the sister taxon to either L. chanarensis or all other Lagerpetidae. Although coeval and geographically close, I. polesinensis and PVSJ 883 do not form a clade exclusive of other lagerpetids. As previously suggested D. gigas Martínez, Apaldetti, Correa & Abelín, 2016 is the sister taxon of D. romeri Irmis et al., 2007. The phylogenetic analyses also indicate that the earliest lagerpetids are restricted to southwestern Pangea, whereas later forms spread across the entire western portion of the supercontinent. Finally, quantification of the codified characters of our analysis reveals that Lagerpetidae is one of the poorest known among the Triassic dinosauromorph groups in terms of their anatomy, so that new discoveries of more complete specimens are awaited to establish a more robust phylogeny. 

2003 ◽  
Vol 81 (6) ◽  
pp. 962-970 ◽  
Author(s):  
Darla K Zelenitsky ◽  
Sean P Modesto

A reappraisal of the eggshell of ratites clarifies aspects of its microstructure and ultrastructure. The phylogenetic usefulness of the eggshell data, consisting of discrete characters, is assessed using eggshell characters alone and by adding the eggshell characters to a data matrix from the literature based on skeletal characters. The resultant tree from the eggshell data alone yields Apteryx as the most basal ratite, dinornithids as the sister taxon of a clade of large living ratites, with Casuarius and Dromaius in a sister-group relationship. The combined eggshell and skeletal analysis revealed most groupings within Ratitae that were based on previous cladistic analysis of the skeletal characters alone, but also supports two equally parsimonious topologies: one identifies Dinornithidae and Apteryx as a clade at the base of Ratitae, and the other identifies Apteryx as the sister taxon of a clade consisting of all the other ratites. It is determined that the characteristics used to define the improperly named "ratite morphotype" in the current eggshell parataxonomy are not synapomorphies of the eggshell of Ratitae. An expanded cladistic analysis of the eggshells of avian and non-avian theropods is required to determine the phylogenetic usefulness of the characteristics of the ratite morphotype.


2009 ◽  
Vol 34 (1) ◽  
pp. 162-172 ◽  
Author(s):  
Katherine G. Mathews ◽  
Niall Dunne ◽  
Emily York ◽  
Lena Struwe

A phylogenetic study and taxonomic revision of the four currently accepted species of Bartonia (Gentianaceae, subtribe Swertiinae) were conducted in order to test species boundaries and interspecific relationships. Species boundaries were examined based on measurements of key quantitative and qualitative morphological characters as given in the original descriptions. Phylogenetic analyses were performed using molecular data from the nuclear internal transcribed spacer region and chloroplast DNA (trnL intron through the trnL-F spacer), separately and combined using parsimony and Bayesian methodologies, incorporating outgroups from subtribes Swertiinae and Gentianinae. The morphological study revealed that characters of one species, B. texana, represent a subset of the morphological variation found within B. paniculata, but that B. paniculata, B. verna, and B. virginica could all be separated from one another. The molecular phylogenetic analyses all found B. texana to nest in a clade with the two recognized subspecies of B. paniculata (subsp. paniculata and subsp. iodandra), making the latter paraphyletic. Bartonia texana is here reduced to subspecific rank, as Bartonia paniculata subsp. texana. Also, the phylogenetic analyses showed strong support for a sister group relationship between B. verna and B. virginica, as opposed to between B. paniculata and B. virginica as has been previously suggested.


2012 ◽  
Vol 279 (1737) ◽  
pp. 2396-2401 ◽  
Author(s):  
Rachunliu G. Kamei ◽  
Diego San Mauro ◽  
David J. Gower ◽  
Ines Van Bocxlaer ◽  
Emma Sherratt ◽  
...  

The limbless, primarily soil-dwelling and tropical caecilian amphibians (Gymnophiona) comprise the least known order of tetrapods. On the basis of unprecedented extensive fieldwork, we report the discovery of a previously overlooked, ancient lineage and radiation of caecilians from threatened habitats in the underexplored states of northeast India. Molecular phylogenetic analyses of mitogenomic and nuclear DNA sequences, and comparative cranial anatomy indicate an unexpected sister-group relationship with the exclusively African family Herpelidae. Relaxed molecular clock analyses indicate that these lineages diverged in the Early Cretaceous, about 140 Ma. The discovery adds a major branch to the amphibian tree of life and sheds light on both the evolution and biogeography of caecilians and the biotic history of northeast India—an area generally interpreted as a gateway between biodiversity hotspots rather than a distinct biogeographic unit with its own ancient endemics. Because of its distinctive morphology, inferred age and phylogenetic relationships, we recognize the newly discovered caecilian radiation as a new family of modern amphibians.


1992 ◽  
Vol 335 (1274) ◽  
pp. 207-219 ◽  

Sphenodon has traditionally been regarded as a little changed survivor of the Permo-Triassic thecodont or eosuchian ‘stem reptiles’ but has alternatively been placed in the Lepidosauria as the plesiomorphic or even apomorphic sister-taxon of the squamates. A cladistic analysis of 16 characters from spermatozoal ultrastructure of Sphenodon and other amniotes unequivocally confirms its exceedingly primitive status. The analysis suggests that monotremes are the sister-group of birds; squamates form the sister-group of a bird + monotreme clade while the three sister-groups successively below the bird + monotreme + squa- mate assemblage are the caiman, the tuatara and the outgroup (turtles). The monotreme + bird couplet, supports the concept of the Haemothermia, but can only be regarded heuristically. The usual concept of mammals as a synapsid-derived outgroup of all other extant amniotes is not substantiated spermatologically. All cladistic analyses made, and a separate consideration of apomorphies, indicate that Sphenodon is spermatologically the most primitive amniote, excepting the Chelonia. It is advanced (apomorphic) for the amniotes in only two of the 16 spermatozoal characters considered. A close, sister-group relationship of Sphenodon with squamates is not endorsed.


2017 ◽  
Vol 83 (6) ◽  
Author(s):  
Abdelhakim Msaddak ◽  
David Durán ◽  
Mokhtar Rejili ◽  
Mohamed Mars ◽  
Tomás Ruiz-Argüeso ◽  
...  

ABSTRACT The genetic diversity of bacterial populations nodulating Lupinus micranthus in five geographical sites from northern Tunisia was examined. Phylogenetic analyses of 50 isolates based on partial sequences of recA and gyrB grouped strains into seven clusters, five of which belong to the genus Bradyrhizobium (28 isolates), one to Phyllobacterium (2 isolates), and one, remarkably, to Microvirga (20 isolates). The largest Bradyrhizobium cluster (17 isolates) grouped with the B. lupini species, and the other five clusters were close to different recently defined Bradyrhizobium species. Isolates close to Microvirga were obtained from nodules of plants from four of the five sites sampled. We carried out an in-depth phylogenetic study with representatives of the seven clusters using sequences from housekeeping genes (rrs, recA, glnII, gyrB, and dnaK) and obtained consistent results. A phylogeny based on the sequence of the symbiotic gene nodC identified four groups, three formed by Bradyrhizobium isolates and one by the Microvirga and Phyllobacterium isolates. Symbiotic behaviors of the representative strains were tested, and some congruence between symbiovars and symbiotic performance was observed. These data indicate a remarkable diversity of L. micranthus root nodule symbionts in northern Tunisia, including strains from the Bradyrhizobiaceae, Methylobacteriaceae, and Phyllobacteriaceae families, in contrast with those of the rhizobial populations nodulating lupines in the Old World, including L. micranthus from other Mediterranean areas, which are nodulated mostly by Bradyrhizobium strains. IMPORTANCE Lupinus micranthus is a legume broadly distributed in the Mediterranean region and plays an important role in soil fertility and vegetation coverage by fixing nitrogen and solubilizing phosphate in semiarid areas. Direct sowing to extend the distribution of this indigenous legume can contribute to the prevention of soil erosion in pre-Saharan lands of Tunisia. However, rhizobial populations associated with L. micranthus are poorly understood. In this context, the diversity of endosymbionts of this legume was investigated. Most Lupinus species are nodulated by Bradyrhizobium strains. This work showed that about half of the isolates from northern Tunisian soils were in fact Bradyrhizobium symbionts, but the other half were found unexpectedly to be bacteria within the genera Microvirga and Phyllobacterium. These unusual endosymbionts may have a great ecological relevance. Inoculation with the appropriate selected symbiotic bacterial partners will increase L. micranthus survival with consequent advantages for the environment in semiarid areas of Tunisia.


2007 ◽  
Vol 21 (3) ◽  
pp. 263 ◽  
Author(s):  
Guilherme Schnell e Schuehli ◽  
Claudio José Barros de Carvalho ◽  
Brian M. Wiegmann

Hypotheses about the evolution of Muscidae have long been the subject of continuous re-evaluation and reinterpretation. Current understandings of the relationships among these flies are based mainly on a single set of characters and are therefore questionable. Our understanding of muscid phylogeny thus needs greater support and further corroboration from additional suites of characters. In the current study, we analysed phylogenetic relationships among 24 species of muscid flies (18 genera and six subfamilies) using 2989 characters derived from sequences of mitochondrial (COI and COII) and nuclear genes (CAD and EF-1α). Data from each gene partition were analysed both in combined and separate phylogenetic analyses using maximum parsimony, maximum likelihood, and Bayesian inference. Support was found for the monophyly of the Muscidae in all analyses and for a sister-group relationship between Coenosiini and Phaoniinae. The latter group was placed in a clade with sampled species of Reinwardtiini and Cyrtoneurininae. The genera Ophyra and Hydrotaea were placed in the Muscinae and a sister-group relationship for Musca and Stomoxys was supported. Sampled species of Polietina form a monophyletic lineage, while Morellia was found to be paraphyletic. Combined analysis of gene partitions improved support and resolution for resulting topologies despite significant incongruence between data partitions found through application of the Incongruence Length Difference test.


2003 ◽  
Vol 17 (1) ◽  
pp. 143 ◽  
Author(s):  
Rienk de Jong

A sister-group relationship of endemic taxa in at least two Gondwanan fragments is considered an indication of a possible Gondwanan ancestry. Without a test of the age of the relationship, such an ancestry remains hypothetical. The relationships of all genera and higher taxa endemic to the Australian region with endemic taxa in other fragments of Gondwana are tested. Out of a total of 207 butterfly genera, 96 genera are endemic. Such a relationship is supported by morphological and molecular characters in a number of analyses in only one case(Cressida with Euryades, in South America). Application of a molecular clock, however, shows the relationship to be not older than c. 30 million years, too young to be the result of the break-up of Gondwana. The other endemic genera generally point to a relationship with the Oriental region, but the relationships of a few genera are still obscure. Consequently, claims of a Gondwanan ancestry in butterflies of the Australian region are ill founded. If such an ancestry exists, it has been obscured by later dispersals and extinctions.


Zootaxa ◽  
2017 ◽  
Vol 4264 (1) ◽  
pp. 1 ◽  
Author(s):  
EDSON H. L. PEREIRA ◽  
ROBERTO E. REIS

A phylogenetic study of the Loricariidae with emphasis on the Neoplecostominae is presented based on a maximum parsimony analysis of 268 phenotypic characters encompassing osteology, arthrology, and external morphology. Results support previous hypotheses of the monophyly of the Neoplecostominae and each of the included genera: Hirtella, Isbrueckerichthys, Kronichthys, Neoplecostomus, Pareiorhaphis, and Pareiorhina. In addition, previously undiscovered diversity was revealed within the subfamily as an additional genus-level taxon, herein described as Euryochus. Relationships among neoplecostomine genera are: (Kronichthys (Euryochus ((Hirtella + Pareiorhaphis) (Pareiorhina (Isbrueckerichthys + Neoplecostomus))))). Additional undescribed diversity was also detected among most neoplecostomine genera and the Hypoptopomatinae. In addition, recently discovered genera Nannoplecostomus and Microplecostomus were included in the analysis, and were identified as sequential sister-taxa to Neoplecostominae + Hypoptopomatinae, which are currently not included in any subfamily and regarded as incertae sedis in Loricariidae. The three species of Lithogenes were included in an encompassing phylogenetic analysis for the first time, and were identified as a monophyletic unit and sister group to all remaining loricariids. The other loricariid subfamilies were also corroborated as monophyletic, and presented the following interrelationships (Lithogeninae (Delturinae (Loricariinae (Hypostominae (Nannoplecostomus (Microplecostomus (Hypoptopomatinae + Neoplecostominae). The Neoplecostominae and its genera are phylogenetically diagnosed, and hypothesized relationships are compared to those of previous morphological and molecular phylogenetic studies.


Author(s):  
Christopher J. Glasby ◽  
Patricia A. Hutchings ◽  
Kathryn Hall

A phylogenetic analysis of the polychaete clade Terebelliformia (Terebellida) was undertaken in order to test monophyly of families and subfamilies and to determine their affinities. Parsimony analyses of 41 terebelliform species with outgroup Owenia fusiformis and 46 morphological characters yielded 106–144 most parsimonious trees with length 250, consistency index=0·432, retention index=0·659 and rescaled consistency index=0·285. Monophyly was indicated for Alvinellidae, Ampharetidae, Terebellidae and Trichobranchidae and the terebellid subfamily Polycirrinae. Monophyly of Terebellidae is supported by the presence of a ridge-like tentacular membrane. Monophyly of Polycirrinae is supported by the loss of branchiae, trilobed upper lip, pinnate secondary notochaetae and ventro-lateral pads. Recognition of Polycirrinae renders taxa in the other terebellid subfamilies—Terebellinae and Thelepodinae—paraphyletic. Our results do not support previous classifications that placed Trichobranchidae as a subfamily of Terebellidae; rather it should be considered equal in rank with Alvinellidae, Ampharetidae, Terebellidae and Pectinariidae. The following relationships were obtained: (Trichobranchidae ((Alvinellidae, Ampharetidae) (Pectinariidae, Terebellidae))). This is the first time a Pectinariidae–Terebellidae sister group relationship has been found; it is supported by the synapomorphic presence of ventral glandular shields.


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