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).

DNA barcoding of a large genus, Aspalathus L. (Fabaceae)

Abstract: The DNA barcode potential of three regions (the nuclear ribosomal ITS and the plastid psbA-trnH and trnT-trnL intergenic spacers) was investigated for the plant genus Aspalathus L. (Fabaceac: Crotalarieae). Aspalathus is a large genus (278 species) that revealed low levels of DNA variation in phylogenetic studies. In a 51-species dataset for the psbA-trnH and ITS regions, 45%, and 16% of sequences respectively were identical to the sequence of at least one other species, with two species undiscriminated even when the two regions were combined. In contrast, trnT-trnL, discriminated between all species in this dataset. In a larger ITS and trnT-trnL dataset. including a further 82 species. 7 species in five pairwise comparisons remained Undiscriminated when the two regions were combined. Four of the five pairs of species not discriminated by sequence data were readily distinguished using a combination of qualitative and quantitative morphological data. The difficulty of barcoding in this group is increased by the presence of intraspecific variation in all three regions studied. In the case of psbA-trnH, three intraspecific samples had a sequence identical to at least one other species. Overall, psbA-trnH. currently a candidate for plant barcoding, was the least discriminatory region in our study.

Systematics of the pentadactylus species group of the frog genus Leptodactylus (Amphibia, Leptodactylidae

Abstract: Heyer, W. Ronald. Systematics of the pentadactylus Species Group of the Frog Genus Leptodactylus (Amphibia: Leptodactylidae). Smithsonian Contributions to Zoology, number 301, 43 pages, 23 figures, 12 tables, 1979.—Sixteen mensural and pattern characters are analyzed for the adult members of the Leptodactylus pentadactylus species group. Available data on tadpoles, mating calls, and karyotypes are incorporated in the analyses. Results of the analyses lead to the recognition of 11 species comprising the group. For each species, the following are provided: synonymy, description of adult characteristics, a distribution map and list of localities, and specimens examined. The following are included if known: distinctive adult colors in life, larval characteristics, mating call description, and karyotype. A key is provided for the adult members of the complex. Larval adaptations appear to be most important in interpreting the evolutionary history within this species group. Adult morphology appears to be evolutionarily rather conservative, contrasting with the patterns found in other species groups so far studied within this genus. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The coral Montastrea cavernosa (Linnaeus). Library of Congress Cataloging in Publication Data Heyer, W. Ronald Systematics of the pentadactylus species group of the frog genus Leptodactylus (Amphibia: Leptodactylidae) (Smithsonian contributions to zoology ; no. 301) Bibliography: p. 1. Leptodactylus—Classification 2. Leptodactylus pentadactylus—Classification. 3. Amphibians —Classification. I. Title. II. Series: Smithsonian Institution. Smithsonian contributions to zoology ; no. 301. QLl.SMno. 301 [QL668.E257] 591'.08s [59T.8] 79-12249

Rare Snakes—Five New Species from Eastern Panama: Reviews of Northern Atractus and Southern Geophis (Colubridae: Dipsadinae)

Abstract: The South American genus Atractus barely enters political North America on the eastern half of the Isthmus of Panama, where it is extraordinarily rare. Collected over a period of 39 years, the five Panamanian specimens of Atractus known to the author represent five species! Four new species are described: A. darienensis, A. hostilitractus, A. imperfectus, and A. depressiocellus. The fifth species is A. clarki Dunn and Bailey, for which a second specimen is reported from the Colombia Choco. The noncapitate hemipenis of A. clarki may be primitive in being calyculate and deeply bilobed. The morphologically convergent Geophis is primarily a Middle American genus—Mexico to western Panama, with two or three outlying species in the western Andes of Colombia (G. betaniensis, G. nigroalbus, and probably G. hoffmanni). The genus is unrecorded from eastern Panama, and a few old records for central Panama seem to have been based on erroneous specimen data. Nonetheless, the genus does occur in east-central Pa...

Varying rates of diversification in the genus Melitaea (Lepidoptera: Nymphalidae) during the past 20 million years

Abstract: The influence of Quarternary glacial cycles on the extant diversity of Holarctic species has been intensively studied. It has been hypothesized that palaeoclimatic changes are responsible for divergence events in lineages. A constant improvement in DNA sequencing and modeling methods, as well as palaeoclimatic reconstruction, permit a deeper exploration of general causes of speciation in geological time. In the present study, we sampled, as exhaustively as possible, the butterflies belonging to the genus Melitaea (Lepidoptera: Nymphalidae), which are widely spread in the Palaearctic region. We conducted analyses to assess the phylogeny of the genus and estimated the timing of divergence and the most likely distribution of ancestral populations. The results obtained indicate that the systematics of the genus is in need of revision and that the diversity of the genus has been profoundly shaped by palaeoenvironmental changes during its evolutionary history. The present study also emphasizes that, when employed with caveats, major palaeoenvironmental events could represent very powerful tools for the calibration of the dating of divergences using molecular data.

Notes some fungicolous Hyphomycetes and their relatives

Abstract: Cladobotryum Nees ex Steud. is redefined and two new species are added to this genus. The uredinicolous genus Colletoconis gen. nov. is segregated from Gloeosporium Desm. & Mont, to accommodate G. aecidiophilum Speg. Engyodontium gen. nov. is erected for Rhinotrichum parvisporum Petch and a similar fungus. The monotypic genus Helminthophora Bon. is redescribed. Sympodiophora G. Arnold is combined with the earlier described genus Pseudohansfordia G. Arnold; eight new combinations are proposed. One new species is added to Denticularia Deighton and two to Sporothrix Hektoen & Perkins; in addition, two new combinations are proposed in the latter genus. A list of doubtful and excluded species formerly classified in the treated genera is given.