نتایج جستجو برای: polychaetes
تعداد نتایج: 819 فیلتر نتایج به سال:
Macrobenthic polychaetes play a significant role in marine benthic food chain. A study was carried out to observe the abundance and diversity of soft bottom macrobenthic polychaetes along the South Indian coast, along with observations on sediment characteristics. The present study indicated an increase in the polychaete diversity as compared to earlier reports. Sixty-three different forms of p...
Vestimentiferan tubeworms are marine invertebrates that inhabit chemosynthetic environments, and although recent molecular phylogenetic analyses have suggested that vestimentiferan tubeworms are derived from polychaete annelids, they show some morphological features that are different from other polychaetes. For example, vestimentiferans lack a digestive tract and have less body segments and co...
A body wall musculature comprising an outer layer of circular fibers and an inner layer of longitudinal fibers is generally seen as the basic plan in Annelida. Additional muscles may be present such as oblique, parapodial, chaetal, and dorsoventral muscles. The longitudinal muscle fibers do not form a continuous layer but are arranged in distinct bands in polychaetes. Mostly there are four to s...
The Marine Ecoregions of the World system separates oceans into 232 ecoregions based on coastal and shelfwater species distributions. We tested separation those delineated subecoregions within Western Australian waters using intertidal macroalgal epiphytic polychaete Environmental predictors assemblages were also determined. collected macroalgae polychaetes 38 rocky shores four marine from 18°S...
Progenesis is defined as the retention of ancestral juvenile characters by adult stages of descendants due to an acceleration of the sexual maturation and thus is often regarded as a fast evolutionary process. Several small, meiofaunal polychaetes, such as Dinophilidae, some "Dorvilleidae" (for example, Parapodrilus), and Protodrilida, exhibit morphological simplicity in that they lack features...
Polychaetes are usually the most abundant taxon in benthic communities and have been most often utilized as indicator species of environmental conditions. This review finds that, while the use of indicator species for a particular pollutant is not simple, polychaetes can provide a useful means of assessing the effects of poor environmental conditions. Polychaetes may be used as sensitive monito...
As a result of their plastic body plan, the relationships of the annelid worms and even the taxonomic makeup of the phylum have long been contentious. Morphological cladistic analyses have typically recovered a monophyletic Polychaeta, with the simple-bodied forms assigned to an early-diverging clade or grade. This is in stark contrast to molecular trees, in which polychaetes are paraphyletic a...
Parasitism is increasingly recognized as an important determinant of population dynamics, productivity and community structure in intertidal ecosystems, and yet there is very little known about the effect of parasites on polychaetes, which represent a major component of the benthic fauna. We surveyed 11 polychaete species from a mudflat in Otago Harbour, New Zealand, and found that seven of the...
sequences in molecular phylogenetic trees is consistent with early observations that polychaetes tend to have relatively short branches in such trees, and hence are useful taxa with which to reconstruct gene family evolution. Also it is clear that the traditional molecular model systems for protostomes (e.g. Drosophila melanogaster and Caenorhabditis elegans), which are restricted to the Ecdyso...
The marine environment is becoming increasingly contaminated by environmental pollutants with the potential to damage DNA, with marine sediments acting as a sink for many of these contaminants. Understanding genotoxic responses in sediment-dwelling marine organisms, such as polychaetes, is therefore of increasing importance. This study is an exploration of species-specific and cell-specific dif...
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