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).

Seagrass taxonomy and identification key

Abstract: This chapter describes how the seagrass species can be identified. Seagrasses are defined as flowering plants growing in shallow marine environment. They form an ecological group and not a taxonomical one. . They are represented by twelve genera, which have been classified in diverse taxonomic groups. These are the entire families: Zosteraceae (three genera), Posidoniaceae (one genus), Cymodoceaceae (five genera), and three of the seventeen genera in the family Hydrocharitaceae. Seagrasses are aquatic plants, which have fewer morphological and anatomical features for species identification than terrestrial flowering plants. Some species have a vast geographic distribution and occupy different niches; this may result in considerable morphological variation, and some of these variations, when studied more closely, may turn out to be separate taxa. All chromosomal studies on seagrasses indicate that chromosome numbers may be different between genera and families, but that the basic numbers are similar among the different species within the same genus. Classification of the various seagrasses in the taxonomic system, and even more their phylogeny, will continue to be debated for many years to come. The definition of seagrasses at the species level is far from satisfactory in certain genera, and can cause difficulties in arriving at a correct identification. Thus, researchers should be careful in citing and interpreting the published literature, which may contain incorrect species names.

Coleofasciculus gen. nov. (cyanobacteria): morphological and molecular criteria for revision of the genus microcoleus gomont(1).

Abstract: Species currently classified within the cyanobacterial genus Microcoleus were determined to fall into two distinct clades in a 16S rDNA phylogeny, one containing taxa within the Oscillatoriaceae, the other containing taxa within the Phormidiaceae. The two lineages were confirmed in an analysis of the 16S-23S internal transcribed spacer (ITS) region sequences and secondary structures. The type species for Microcoleus is M. vaginatus Gomont, and this taxon belongs in the Oscillatoriaceae. Consequently, Microcoleus taxa in the Phormidiaceae must be placed in separate genera, and we propose the new genus Coleofasciculus to contain marine taxa currently placed in Microcoleus. The type species for Coleofasciculus is the well-studied and widespread marine mat-forming species Microcoleus chthonoplastes (Mert.) Zanardini ex Gomont. Other characters separating the two families include type of cell division and thylakoid structure.