Search results for "Systematics"

Reëvaluation of Orthotrichum Rhytiore (Orthotrichaceae)

2008

Examination of the holotype of Orthotrichum rhytiore B. H. Allen reveals gametophytic characters which support the placement of the species in Ulota. The species is peculiar within the genus due to its unusual sporophyte morphology, and the occurrence of these sporophytic characters in Ulota is discussed. Ulota rhytiore (B. H. Allen) F. Lara, Garilleti, Albertos & Mazimpaka comb. nov. is the first known species of the genus in tropical America.

Systematics and population genetics of the coldwater (Etheostoma ditrema) and watercress (Etheostoma nuchale) darters, with comments on the Gulf dart…

2005

Abstract Current taxonomy of the Etheostoma asprigene species group recognizes four species, two of which ( Etheostoma ditrema Ramsey and Suttkus and Etheostoma nuchale Howell and Caldwell) are restricted to isolated springs and spring-fed stream systems above the Fall Line of the Mobile Basin of Alabama, Georgia, and Tennessee. Previous studies of morphological and biochemical variation between disjunct populations of E. ditrema support the presence of multiple independent lineages. Unfortunately, the lack of phylogenetic methodology has made it impossible to distinguish historically differentiated non-sister taxa from currently intergrading sister lineages. The current study examines memb…

A new species of glirid rodent Vasseuromys from the Aragonian (Miocene) of the Ebro Basin (North−Eastern Spain)

2012

We describe a new species of Vasseuromys from the locality of Pico del Fraile 2 (PF2) in the Ebro Basin of northeastern Spain, which has yielded a fauna comprising several rodents and insectivores (Eumyarion cf. weinfurteri, Mega−cricetodon cf. primitivus, Democricetodon aff. hispanicus, Spermophilinus cf. besana, Microdyromys cf. legidensis, Galerix sp., and Lagomorpha indet.) indicative of Aragonian zones C or D. Vasseuromys cristinae sp. nov. differs from other Vasseuromys species in the constant presence of four extra ridges on the lower molars, one of them being connected to the posterolophid in the posterior valley, as well as three extra ridges on the upper molars, with none of them …

Towards a complete phylogeny of African Melastomateae : systematics of Dissotis and allies (Melastomataceae)

2020

Aegopinella bourdieri nov. sp. (Gastropoda: Zonitidae),une espèce nouvelle du Pléistocène normand (France)

1989

St Pierre-les-Elbeuf (Normandy, NE France) is a reference site for the middle and the upper Pleistocene of NW France. In the eastern part of the quarry, the paleosoils Elbeuf III and IV are truncated, white sands and a small tufa lay on Elbeuf IV. Similar deposits have been recognized at Vernon (Seine valley) and at Arrest (northern France). They are probably contemporaneous (Holsteinian) and each of them has yielded an interglacial malacological fauna. The faunal communities are interesting because they are composed by species living up to now in this country, by emigrated species and by fossil species. Among them, A. bourdieri is a new fossil taxa, endemic of Holsteinian tufas of Normandy…

A reassessment of the sections of the genus Cytisus Desf. (Cytiseae, Leguminosae)

2006

Recent morphological and molecular research on Cytisus and allied genera has produced a great deal of new data relevant to systematics, which have not yet been incorporated into a consistent classification system of the genus. We have compared and evaluated recently published cladograms and phenograms based on morphological and molecular (nuclear and plastid DNA) characters. The genus Cytisus sensu lato, including Calicotome, Chamaecytisus, Chronanthus, and Lembotropis, appears to be monophyletic. A subdivision of the genus Cytisus in 13 sections is presented; one species, C. tribracteolatus, remains incertae sedis. A new section (C. sect. Dendrocytisus) and two new combinations for taxa in…

Evolution of the grapevine (Vitis viniferaL.) imprinted by natural and human factorsThis review is one of a selection of papers presented at the symp…

2007

This paper is concerned with vegetative reproduction, which is the only mode of propagation in cultivated grapevines. After a brief summary of the systematics of the Vitaceae the question of the nomenclature of cultivated grapevines is discussed. Intra-varietal variability is discussed using morphological and molecular characteristics. The origins of variation are presented: mutations, foreign nucleic acids, and memory of previous environmental conditions. Grapevines provide characteristic products, leading viticulturalists to make selections among the diversity observed in the vineyard, thus decreasing diversity. Grapevines interact with various environmental agents. One example, the natur…

Phylogenetic analysis of the Antarctic genus Oswaldella Stechow, 1919 (Hydrozoa, Leptomedusae, Kirchenpaueriidae)

1999

A cladistic study was carried out on known species of the characteristically Antarctic genus Oswaldella, adopting as out-groups some other genera included in the family Kirchenpaueriidae. The analysis resulted in a cladogram with low CI in which no relationship between genera can be depicted. However, the hypothesis of monophyly of the genus Oswaldella is corroborated, being supported in our cladogram by five synapomorphies (although all are homoplastic with other taxa or reversed within the species of the genus). The basal relationships of the genus are uncertain, but three species groups are distinguishable within Oswaldella: 1) the O. incognita group, 2) the O. Antarctica group, and 3) a…

A taxonomical study of the subtribe leontodontinae based on the distribution of phenolic compounds

1993

Abstract Evaluation of the phenolic constituents of five species belonging to the subtribe Leontodontinae (family Asteraceae) allowed the identification of ten flavonoid and eight phenolic acids by means of HPLC and other standard methods. The role of these compounds in relation to the morphological characteristics in the systematics of the subtribe is discussed.

Local adaptation, coadaptation, and population boundaries

1986

Coadaptation can occur either because of local adaptation in a geographically widespread population and/or because of intrinsic adaptation to the state of other genes or chomosomes. In either event, hybridization between animals with differently coadapted gene or chromosomal complexes can result in a decrease in fertility, viability, etc. in the initial hybrids and especially in later generations. This is known as an outbreeding depression. Moreover, releasing animals not adapted to the local environment can seriously hamper the effectiveness of a reintroduction program, and hybridization can also destroy the local adaptation. Coadapted gene complexes are best detected through studies on na…