Regeneration mechanisms in Syllidae Annelida. Syllids have striking ability to regenerate their body anteriorly and posteriorly, which in many species is redeployed during sexual schizogamy and asexual fission reproduction.
This review summarizes the available data on regeneration in syllids, covering descriptions of regenerative mechanisms in different species as well as regeneration in relation to reproductive modes.
Our survey shows that posterior regeneration is widely distributed in syllids, whereas anterior regeneration is limited in most of the species, excepting those reproducing by fission. The latter reproductive mode is well known for a few species belonging to Autolytinae, Eusyllinae, and Syllinae.
Patterns of fission areas have been studied in these animals.
Deviations of the regular regeneration pattern or aberrant forms such as bifurcated animals or individuals with multiple heads have been reported for several species. Identification key to Nephtyidae Annelida of the Sea of Okhotsk. Directory of Open Access Journals Sweden. A new user-friendly identification key is presented with a brief description for each species.
The taxonomic positions of three closely related species, Nephtys brachycephala Moore,N. The distributions of two species, Nephtys discors Ehlers, and N.
Full Text Available Water pollution is the entry or inclusion of substances, energy and other components into the water by human activities, so that water quality decrease to a certain level. This Reproduccion asexual vegetativa bulbospinal tract a timed to monitor the pollution of aquatic environment in the Badung River and Mati River by using Annelida phylum as bioindicator, the study was conducted from February to March The data obtained were analyzed by the structure of the community, and also used ABC Abudance-Biomass Comparison method.
The result of the research showed that the most abundance of Annelida and dominant from all stations of Badung River and Mati River was Lumbriculus variegatus. Is showed that it contamination status was categorized as mild contamination because it was dominant by facultative organism. The structure of the Annelida community in the Badung River and Mati River with the value of the diversity index was categorized as low Reproduccion asexual vegetativa bulbospinal tract H ' Annelida community 0.
The analysis environmental pollution condition of Badung River and Mati River with Annelida as bioindicator by using ABC method showed that were medium contaminated.
Phylogeny and systematics of Protodrilidae Annelida inferred with total evidence analyses. Protodrilidae is a group of small, superficially simple-looking annelids, lacking chaetae and appendages, except for two prostomial palps. Originally considered to be one of the primitive "archiannelid" families, its affinity within Annelida is still highly debated. Protodrilids are found worldwi Diversity and distribution of Tubificidae, Naididae, and Lumbriculidae Annelida: Oligochaeta in the Netherlands: Data from 24 water management districts and the rivers Rhine and Meuse in the Netherlands were used to study geographical distribution, relative occurrence, and environmental requirements of 76 aquatic oligochaetes families Tubificidae, Naididae, and Lumbriculidae AnnelidaClitellata.
The mitochondrial genome of the sipunculid Phascolopsis gouldii supports its association with Annelida rather than Mollusca. We have determined the sequence of about half nts of the mitochondrial genome of the sipunculid Phascolopsis gouldii, the first representative of this phylum to be so studied. All of the 19 identified genes are transcribed from the same DNA strand.
The arrangement of these genes is remarkably similar to that of the oligochaete annelid Lumbricus terrestris. Comparison of both the inferred amino acid sequences and the gene arrangements of a variety of diverse metazoan taxa reveals that the phylum Sipuncula is more closely related to Annelida than to Mollusca. This requires reinterpretation of the homology of several embryological features and of patterns of animal body plan evolution. Full Text Available We present the spatial distribution and abundance of the holoplanktonic family Iospilidae AnnelidaPolychaeta, along part of the eastern Brazilian coast, and its relation to environmental variables in the region.
We analyzed environmental variables: Both species are mainly distributed in the oceanic region stations. The distribution of P. Significant differences between samples and between sectors of the continental shelf and oceanic region were found. Interactions between sediment chemistry and frenulate pogonophores Annelida in the north-east Atlantic.
The small frenulate pogonophores Annelida: Siboglinidae typically inhabit muddy sediments on the continental slope, although a few species occur near hydrothermal vents and cold seeps. The environments inhabited include: All the species studied obtain nutrition from endosymbiotic bacteria.
They take up reduced sulphur species, or in one case, methane, through the posterior parts of their tubes buried in the anoxic sediment. We conclude that most species undertake sulphide 'mining', a mechanism previously Reproduccion asexual vegetativa bulbospinal tract in the bivalves Lucinoma borealis and Thyasira sarsi.
These pogonophores participate in the sulphur cycle and effectively lower the sulphide content of the sediments. Our results show that the abundance of frenulate pogonophores increases with increasing sedimentation and with decreasing abundance of other benthos, particularly bioturbating organisms.
The maximum sustainable carrying capacity of non-seep sediments for frenulate pogonophores is limited by the rate of sulphate reduction. Sphaerodoropsis kitazatoi, a new species and the first record of Sphaerodoridae Annelida: Phyllodocida in SW Atlantic abyssal sediments around a whale carcass. A new polychaete species, Sphaerodoropsis kitazatoi Annelida: This species was found in sediments impacted by a whale carcass.
The new species has four longitudinal rows of macrotubercles Reproduccion asexual vegetativa bulbospinal tract one transversal row per chaetiger and shares several characters with S.
They can be clearly distinguished from S. Sigalionidae en el golfo de Vizcaya. Sigalionidae han sido identificados. Esta es la primera referencia de la especie para el golfo de Vizcaya. Los ejemplares fueron obtenidos en fondos blandos circalitorales de la Reproduccion asexual vegetativa bulbospinal tract continental de Zarautz Costa vasca, SE del golfo de Vizcaya.
Metabolic rates, enzyme activities and chemical compositions of some deep-sea pelagic worms, particularly Nectonemertes mirabilis Nemertea; Hoplonemertinea and Poeobius meseres Annelida ; Polychaeta. Investigations of metabolic rate, enzyme activity and chemical composition were undertaken on two abundant deep-sea pelagic worms: Six other species of worms Pelagonemertes brinkmanni Nemertea and the following polychaetes: Pelagobia species A, Tomopteris nisseni, Tomopteris pacifica, Tomopteris species A, and Traviopsis lobifera were captured in smaller numbers and used for comparison in the physiological and biochemical measurements.
worms had the highest oxygen consumption rates and, along with N. Poeobius meseres had the lowest rates of oxygen consumption and displayed no significant relationship of oxygen consumption rate to wet weight. Reproduccion asexual vegetativa bulbospinal tract significant effect of size on the activities of citrate synthase, lactate dehydrogenase or pyruvate kinase was observed in P.
Lipid content was higher than protein content for all the worms in this study. Carbohydrate was of little significance in these worms and was usually metabolic rates. It appears that polychaete worms as a group have higher metabolic rates than bathypelagic shrimps, copepods and fishes, and may be the animals with the highest metabolic rates in the bathypelagic regions of the world's oceans.