Topic
Genus
About: Genus is a research topic. Over the lifetime, 68921 publications have been published within this topic receiving 590966 citations. The topic is also known as: monospecies genus & genus (zoology).
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TL;DR: The present study employed allozymic and morphological analyses to ascertain the taxonomic status of six species in the genus Bosmina from North America.
Abstract: Prior morphological studies have led to the recognition of six species in the genus Bosmina from North America. The present study employed allozymic and morphological analyses to ascertain the taxo...
120 citations
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TL;DR: The chromosome banding patterns of all seven extant species of the horse family, Equidae, are presented.
Abstract: The chromosome banding patterns of all seven extant species of the horse family, Equidae, are presented. This mammalian family is composed of a single genus, Equus, notable for its rapid karyotypic ev
120 citations
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TL;DR: The phylogenetic analysis of new mitochondrial DNA sequences of 58 species of Macrobrachium distributed mainly in America support the hypothesis of monophyly of this genus, and conclude that the independent evolution of different types of life cycle must have occurred more than once in the history of the group.
Abstract: The genus Macrobrachium Bate, 1868 is one of the best examples of widespread crustacean genera distributed globally throughout tropical and subtropical waters. Previous investigators have noted the systematic complexity of the group, and have suggested rearrangements within the family Palaemonidae. Our phylogenetic analysis of new mitochondrial DNA sequences of 58 species of Macrobrachium distributed mainly in America support the hypothesis of monophyly of this genus, if Cryphiops Dana, 1852 is accepted as a generic synonym. We concluded that the independent evolution of different types of life cycle (abbreviated larval development – ALD and extended larval development – ELD) must have occurred more than once in the history of the group. Similarly, we also concluded that the current type species of the genus, Macrobrachium americanum Bate, 1868, should not be considered valid, as previously proposed. The synonymy of two members of the ‘olfersi’ species complex (M. birai Lobao, Melo & Fernandes, 1986 and M. holthuisi Genofre & Lobao, 1978) with M. olfersi (Wiegmann, 1836) was confirmed. Similar results were found in comparing M. petronioi Melo, Lobao & Fernandes, 1986 and M. potiuna (Muller, 1880), in which the genetic divergence placed M. petronioi within the level of intraspecific variation of M. potiuna. The taxonomic status of the genus Cryphiops, as well as theories on the origin of Macrobrachium, is also called into question.
119 citations
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TL;DR: The results definitely support the monophyly of the genus Artemisia in its broadest sense and suggest that some infrageneric groups must be redefined, especially the subgenus Artemisia.
Abstract: Sequences of the internal transcribed spacers (ITS1 and ITS2) of nuclear ribosomal DNA were analysed for 44 Artemisia species (46 populations) representing all the five classical subgenera and the geographical range of the genus, 11 species from 10 genera closely related to Artemisia, and six outgroup species from five other genera of the Anthemideae. The results definitely support the monophyly of the genus Artemisia in its broadest sense (including some taxa segregated as independent genera, like Oligosporus and Seriphidium). Eight main clades are established in this molecular phylogeny within Artemisia; they agree in part with the classical subdivision of the genus, but they also suggest that some infrageneric groups must be redefined, especially the subgenus Artemisia. The subgenera Tridentatae and Seriphidium are independent from each other. Some of the satellite genera are clearly placed within Artemisia (Artemisiastrum, Filifolium, Mausolea, Picrothamnus, Sphaeromeria, Turaniphytum), whereas some others fall outside the large clade formed by this genus (Brachanthemum, Elachanthemum, Hippolytia, Kaschgaria). Our results, correlated to other data such as pollen morphology, allow us to conclude that the subtribe Artemisiinae as currently defined is a very heterogeneous group. Affinities of the largest genus of the subtribe and tribe, Artemisia, and of other genera of the subtribe to some genera from other subtribes of the Anthemideae strongly suggest that subtribe Artemisiinae needs a deep revision and redefinition. Phylogenetic utility of region trnL-F of the plastid DNA in the genus Artemisia and allies was also evaluated: sequences of the trnL-F region in Artemisia do not provide phylogenetic information.
119 citations
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TL;DR: The genus Cercaria was established by O. F. Mueller on the basis of eight species and Bory de Saint-Vincent named and characterized six genera, which he grouped into the new family Cercari6es.
Abstract: The genus Cercaria was established by O. F. Mueller (1773, p. 64) on the basis of eight species, namely, C. gyrinus, C. catellus, C. podura, C. lupus, C. lemna, C. cyclidium, C. tenax, and C. pleuronectes. Mueller later (1776, 1786) added fourteen species, including C. discus, C. tripos, C. turbo, and C. viridis. The first attempt to divide the species of Cercaria among several smaller genera was made by Nitzsch. In a footnote on page 4 of his paper, "Beitrag zur Infusorienkunde oder Naturbeschreibung der Zerkarien und Bazillarien," published in Neue Schriften der naturforschenden Gesellschaft zu Halle, Dritter Band, Heft I, 1817 **), Nitzsch proposed the recognition of twelve genera, mentioning included species but failing to give names or diagnoses for new genera. In 1823 Bory de Saint-Vincent (pp. 355, 356) named and characterized six genera, which he grouped into the new family Cercari6es. These genera were treated individually and assigned species in various articles in the Dictionnaire Classi-
119 citations