Elassoma, the Pygmy Sunfishes, has long proven difficult to classify among the more than 15,000 species of percomorph fishes. Hypotheses dating to the 19th Century include Elassoma in Centrarchidae or in the monogeneric Elassomatidae, and more recent phylogenetic hypotheses have classified Elassoma in Smegmamorpha that also contained Synbranchiformes, Mugiliformes, Gasterosteiformes, and Atheri...

Complete mitochondrial 16S rRNA gene sequences from 35 caenogastropods were obtained to evaluate the phylogenetic relationship of the family Buccinidae at the intra-supra familial level. With respect to intergeneric relationships within the family, the molecular phylogeny supported three clades with statistical significance: Buccinum + Neptunea, Engina + Pisania + Pollia and Penion + Kelletia. ...

Cnidaria, the sister group to Bilateria, is a highly diverse group of animals in terms of morphology, lifecycles, ecology, and development. How this diversity originated and evolved is not well understood because phylogenetic relationships among major cnidarian lineages are unclear, and recent studies present contrasting phylogenetic hypotheses. Here, we use transcriptome data from 15 newly-seq...

Gene sequence data from the small-subunit ribosomal RNA coding region were used to explore evolutionary relationships among the colonial spumellarian radiolaria (Polycystinea). Representatives from the two spumellarian families known to form colonies were considered including the following taxa: Sphaerozoidae: Collozoum pelagicum; Collozoum serpentinum; Rhaphidozoum acuferum; Sphaerozoum puncta...

The type species of the monotypic beetle genus Rioneta Johnson, 1975, previously known from three specimens, is rediscovered in the Uluguru Mountains, Tanzania. A second sympatric species, R. inexpectata sp.n., is described. The relatively rare event of apparently obligate aptery in Ptiliidae is reported. The genus Rioneta, as well as Leptinla Johnson, 1985, are removed from the non-monophyleti...

An analysis of public DNA barcoding data confirms that the extraction of Arboricaria Bosmans, 2000 from the genus Micaria Westring, 1851 would require the division of Micaria into at least five (and probably more) individual genera, to restore the monophyly of Micaria sensu stricto. Such an excessive splitting of a homogenous and well-defined genus would be neither desirable nor practical, and ...

A “covarion” model for nucleotide substitution which allows sites to turn “on” and “off” with time was proposed 27 years ago by Fitch and Markowitz. It has been argued recently that evidence supports such models over later, alternative models which postulate a static distribution of rates across sites. However, in contrast to these latter well-studied models, little is known about the analytic ...

A reexamination of the scierai ossicles of sceloporine iguanids was undertaken after conflicting data sets were discovered in the literature. The scierai ossicles of certain other iguanids were also studied for comparative purposes. Sceloporines exhibit much greater variation in ossicle configuration than has previously been reported. This variation is often too great within genera and species ...

Lophotrochozoa has been consistently recovered in molecular phylogenetic analyses using different markers. Current knowledge of lophotrochozoan relationships is reviewed and the place that parasites occupy in this phylogeny is discussed. Two major taxa are identified within Lophotrochozoa: Platyzoa and Trochozoa. Monophyly of both taxa is still under debate. Relationships within Trochozoa remai...