Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Polychaeta”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed2006

Marine invertebrate cytochrome P450: emerging insights from vertebrate and insects analogies.

Cytochrome P450 enzymes (P450s) are responsible for the oxidative metabolism of a plethora of endogenous and exogenous substrates. P450s and associated activities have been demonstrated in numerous marine invertebrates belonging to the phyla Cnidaria, Annelida (Polychaeta), Mollusca, Arthropoda (Crustacea) and Echinodermata. P450s of marine invertebrates and vertebrates show considerable sequence divergence and the few orthologs reveal the selective constraint on physiologically significant enzymes. P450s are present in virtually all tissues of marine invertebrates, although high levels usually are found in hepatic-like organs and steroidogenic tissues. High-throughput technologies result in the rapid acquisition of new marine invertebrate P450 sequences; however, the understanding of their function is poor. Based on analogy to vertebrates and insects, it is likely that P450s play a pivotal role in the physiology of marine invertebrates by catalyzing the biosynthesis of signal molecules including steroids such as 20-hydroxyecdysone (the molting hormone of crustaceans). The metabolism of many exogenous compounds including benzo(a)pyrene (BaP), pyrene, ethoxyresorufin, ethoxycoumarin and aniline is mediated by P450 enzymes in tissues of marine invertebrates. P450 gene expression, protein levels and P450 mediated metabolism of xenobiotics are induced by PAHs in some marine invertebrate species. Thus, regulation of P450 enzyme activity may play a central role in the adaptation of animals to environmental pollutants. Emphasis should be put on the elucidation of the function and regulation of the ever-increasing number of marine invertebrate P450s.

Animals↗
PubMed2005

Components of the cytochrome P450-dependent monooxygenase system and 'NADPH-independent benzo[a]pyrene hydroxylase' activity in a wide range of marine invertebrate species.

Levels of components of the cytochrome P450 (CYP)-dependent monooxygenase system were characterised in microsomes of major biotransformation tissues, or whole bodies, of 33 species from six phyla of aquatic invertebrates. The phylogenetic distribution of benzo[a]pyrene hydroxylase (BPH) activity in the absence of added NADPH (so-called 'NADPH-independent BPH activity') and presence of NADPH was also examined. Microsomal protein yield was higher in individual tissues than whole tissues. The main components (total CYP and cytochrome b5; NADPH-dependent cytochrome c (CYP) reductase, NADH-dependent cytochrome c reductase and NADH-dependent ferricyanide (b5) reductase activities) were found in most species of the Porifera, Cnidaria, Mollusca, Polychaeta, Crustacea and Echinodermata examined. The so-called '418-peak' of the carbon-monoxide difference spectrum of reduced microsomes was found in all species, indicating the wide distribution of this protein. Total CYP levels (pmol mg(-1) protein; mean+/-SEM) were similar in molluscs (50+/-7), crustaceans (61+/-11) and echinoderms (56+/-9), with the exception of high levels (223-266) in two crustacean species. NADPH-dependent BPH activity (pmol min(-1) mg(-1) protein) was found in 32 species, being lowest in Porifera and Cnidaria (3-4), intermediate in Mollusca (7.8+/-1.3), and highest in Crustacea (25+/-4) and Echinodermata (15+/-4). NADPH-independent BPH activity was evident in 13 out of 15 molluscan species examined, with the addition of NADPH either stimulating (8 species) or inhibiting (5 species) the activity. NADPH-independent BPH activity was also seen in two poriferan species and indicated in three crustacean species, suggesting that the phenomenon is not solely restricted to the Mollusca.

Animals↗
PubMed2005

An in situ postexposure feeding assay with Carcinus maenas for estuarine sediment-overlying water toxicity evaluations.

This study developed and evaluated a short-term sublethal in situ toxicity assay for estuarine sediment-overlying waters, with the crab Carcinus maenas (L.) based on postexposure feeding. It consisted of a 48-h in situ exposure period followed by a short postexposure feeding period (30 min). A precise method for quantifying feeding, using the Polychaeta Hediste (Nereis) diversicolor Müller as food source, was first developed. The sensitivity of the postexposure feeding response was verified by comparing it to that of lethality, upon cadmium exposure. The influence of environmental conditions prevailing during exposure (salinity, temperature, substrate, light regime, and food availability) on postexposure feeding was also addressed. The potential of this in situ assay was then investigated by deploying organisms at ten sites, located in reference and contaminated Portuguese estuaries. Organism recovery ranged between 90% and 100% and a significant postexposure feeding depression (16.3-72.7%) was observed at all contaminated sites relatively to references.

Animals↗
PubMed2006

Application of public-domain statistical analysis software for evaluation and comparison of comet assay data.

A novel approach for statistical analysis of comet assay data (i.e.: tail moment) is proposed, employing public-domain statistical software, the R system. The analytical strategy takes into account that the distribution of comet assay data, like the tail moment, is usually skewed and do not follow a normal distribution. Probability distributions used to model comet assay data included: the Weibull, the exponential, the logistic, the normal, the log normal and log-logistic distribution. In this approach it was also considered that heterogeneity observed among experimental units is a random feature of the comet assay data. This statistical model can be characterized with a location parameter m(ij), a scale parameter r and a between experimental units variability parameter theta. In the logarithmic scale, the parameter m(ij) depends additively on treatment and random effects, as follows: log(m(ij)) = a0 + a1x(ij) + b(i), where exp(a0) represents approximately the mean value of the control group, exp(a1) can be interpreted as the relative risk of damage with respect to the control group, x(ij) is an indicator of experimental group and exp(b(i)) is the individual risk effects assume to follows a Gamma distribution with mean 1 and variance theta. Model selection is based on Akaike's information criteria (AIC). Real data coming from comet analysis of blood samples taken from the flounder Paralichtys orbignyanus (Teleostei: Paralichtyidae) and from samples of cells suspension obtained from the estuarine polychaeta Laeonereis acuta (Nereididae) were employed. This statistical approach showed that the comet assay data should be analyzed under a modeling framework that take into account the important features of these measurements. Model selection and heterogeneity between experimental units play central points in the analysis of these data.

Animals↗
PubMed2005

Novel excitatory neuropeptides isolated from a prosobranch gastropod, Thais clavigera: The molluscan counterpart of the annelidan GGNG peptides.

The GGNG peptides are excitatory neuropeptides identified from earthworms, leeches and polychaeta. Two structurally related peptides were purified and characterized from a mollusk, Thais clavigera (prosobranch gastropod). The peptides designated as Thais excitatory peptide-1 (TEP-1) (KCSGKWAIHACWGGN-NH2) and TEP-2 (KCYGKWAMHACWGGN-NH2) are pentadecapeptides having one disulfide bond and C-terminal GGN-NH2 structures, which are shared by most GGNG peptides. TEP augmented the motilities of Thais esophagus and penial complex. TEP-like immunoreactivity is distributed in both the neurons of the central nervous system and nerve endings in the penial complex. Thus, the involvement of TEP in the contraction of the digestive and reproductive systems is suggested. Substitution of amino acids in TEP revealed that two tryptophan residues in TEP are important for maintaining bioactivity.

Amino Acid Sequence↗
PubMed2001

Settlement of Pomatoceros lamarkii (Serpulidae) larvae on biofilmed surfaces and the effect of aerial drying.

The settlement responses of Pomatoceros lamarkii (Polychaeta: Serpulidae) larvae to biofilms of varying age on slate surfaces and to dried biofilms on slate surfaces were investigated in the laboratory. Settlement experiments were performed as multi-treatment, still water assays. Larvae did not settle on clean, non-biofilmed slates but settled on biofilms up to 28 days old. Settlement intensity was closely related to the bacterial density of a biofilm. Drying a biofilmed surface for 1-2 h at 20 degrees C to simulate a single tidal emersion completely negated the former inductive effect of the biofilm. Drying also negated the larval settlement-inducing effect that normally results from the presence of conspecific adults. The settlement inhibition lasted for approximately 5 days following a single drying event. Larvae settled readily on biofilms exposed to formalin and antibiotics. Treating biofilms with formalin or antibiotics before or after drying had no effect upon larval avoidance of dried biofilms. Freeze-drying a biofilm had the same effect as aerial drying. The biofilm drying effect could not be mimicked by exposing biofilms to hyper-saline seawater. The finding that P. lamarkii larvae do not settle on dried biofilms could have significance in explaining the natural distribution of this species in the intertidal.

Journal Article↗
PubMed1998

Annelid cytochrome P-450.

Both classes of Annelida--Polychaeta and Clitellata--have been shown to contain cytochrome P-450. The metabolism of a number of aromatic hydrocarbons, drugs and pesticides by annelids required oxygen and NADPH, and was inhibited by a variety of cytochrome P-450 inhibitors. A number of types I and II substrates bound to the cytochrome P-450 in polychaete microsomes to give typical types I and II binding spectra. These results suggest that xenobiotics in annelids are metabolized by a typical cytochrome P-450 mixed function oxygenase. In addition to xenobiotics, annelid cytochrome P-450 systems are likely to function in the biosynthesis and metabolism of sterols and hormones found in annelids, such as cholesterol, ecdysteroids and eicosanoids. The primary source of cytochrome P-450 isolated to date from annelids has been intestinal microsomes. Cytochrome P-450 concentrations in these microsomes varied from 8 to 580 pmol mg-1 of protein. The only cytochrome P-450s purified from annelids were the three isomers isolated from microsomes of the oligochaete, Lumbricus terrestris, whose molecular masses were 48,000, 51,000 and 53,000 Da. Work on the induction of cytochrome P-450 in polychaetes by exposure to polycyclic aromatic hydrocarbons or polychlorinated biphenyls has given conflicting results, since some groups found induction after such exposure, but others found no induction. One possible explanation may be exposure to natural soil and sediments inducers, e.g. plant alkaloids, during feeding. Since gene and protein sequences have yet to be carried out on the cytochrome P-450 of any annelid, the relationship of annelid cytochrome P-450s to the 74 families of P-450 so far found, remains to be carried out.

Animals↗
PubMed2003

Phylogeny and evolution of reproductive modes in Autolytinae (Syllidae, Annelida).

The phylogeny of 31 autolytine taxa (Syllidae, Polychaeta, and Annelida) was estimated based on 16S rDNA and 18S rDNA sequences. Outgroups included 12 non-autolytine syllids and four other annelids from related groups. The phylogeny was used to trace the evolution of the various reproductive strategies (i.e., epigamy, anterior and posterior scissiparity, and gemmiparity) within the group, and it will also serve as a basis for a forthcoming revision of autolytine taxonomy. The two genes were analysed both separately and in combination using parsimony, maximum likelihood, and Bayesian inference. Regardless of method used the combined analysis supported a division of Autolytinae into three major clades: one with epigamous Autolytus; a second comprising Autolytus and Myrianida with posterior scissiparity and gemmiparity; and a third containing Proceraea, Procerastea, and Virchowia with anterior scissiparity. The relationship between these three groups is uncertain. Ancestral reproductive states were reconstructed with parsimony and maximum likelihood, and the results unequivocally support epigamy as the plesiomorphic reproductive mode in Syllidae, and that schizogamy in Syllinae and Autolytinae are separate events. The evolution of reproductive traits is ambiguous within Autolytinae, and either of the different reproductive modes could represent the ancestral state.

Animals↗
PubMed1972

Proventriculus of a marine annelid: muscle preparation with the longest recorded sarcomere.

EACH MUSCLE OF THE SYLLID (ANNELIDA: Polychaeta) proventriculus, the region of the gut posterior to the pharynx, contains a single zigzagging Z band, flanked on each side by a sequence of I-A-H-A-I bands defined by thick (60-90 nm) and thin (5 nm) filaments. The thick filaments show a 14-nm periodicity similar to paramyosin. The muscle cell terminates at the level of the outer I bands. The muscle does not include a complete sarcomere in the strict sense, as defined by a pair of Z bands, but the equivalent H-H distance reaches about 40 mum. Electrophysiological evidence suggests that contraction and relaxation of the cell are, respectively, associated with depolarizing and hyperpolarizing potentials.

Animals↗
PubMed1972

Intergroup phylogenies in Drosophila as determined by comparisons of salivary banding patterns.

A salivary gland chromosome phylogeny is presented which summarizes the evolutionary relationships of twenty-two species belonging to the sub-genus Drosophila, and members of the twelve species groups: D. melanica, D. repleta, D. carbonaria, D. polychaeta, D. annulimana, D. robusta, D. carsoni, D. virilis, D. funebris and the "picture-wing," D. mimica and D. crassifemur groups (of Hawaii).-Photographic salivary chromosome maps were prepared for all twenty-two species studied. While the chromosomes of different species belonging to the same group can usually be homologized almost completely, so that construction of intragroup phylogenies is easy, chromosomes of members of different groups are so modified structurally that in most cases only short sections can be fully homologized, and these in only one or two chromosome elements.-Broadly homologous chromosome elements were compared for three species at a time, and on the basis of overlapping homologous sections, or overlapping inversions included within homologous sections, the trio of chromosomes, and the species to which they belonged can often be arranged in a two-step phylogenetic series. Detection of many such ordered trios permits construction of a single phylogenetic scheme encompassing all species.-D. nigromelanica, of the D. melanica group is found to be chromosomally intermediate between the rest of its group and the species belonging to other groups, suggesting that it is the most nearly ancestral member of its group. When trios of species including D. nigromelanica and members of two other species groups are compared, it is found that in twelve of fourteen such comparisons the chromosomes of D. nigromelanica are structurally intermediate between those of the members of the other two species groups, indicating the central position of D. nigromelanica in the phylogeny as a whole.-Available cytological evidence indicates that among the nine continental groups studied, it is the D. robusta group which is chromosomally closest to the Hawaiian "picture-wing" groups. Among the members of the Hawaiian groups it is D. primaeva and D. attigua which are found to be closest to the continental species. This finding tends to confirm the earlier conclusion of Carson and Stalker, based on different evidence, that the above two species were in an ancestral position in the Hawaiian phylogeny.-The relationship of the D. robusta and D. melanica groups demonstrated in this paper, the phylogenies within each of these two groups earlier worked out by Narayanan and by Stalker, and the present geographical distributions of the species within them, require that at least three Asiatic-New World migrations must have occurred during the evolution of the two groups.

Animals↗
PubMed2000

Mitochondrial genomes of Galathealinum, Helobdella, and Platynereis: sequence and gene arrangement comparisons indicate that Pogonophora is not a phylum and Annelida and Arthropoda are not sister taxa.

We report a contiguous region of more than half (> 7,500 nt) of the mitochondrial genomes for Platynereis dumerii (Annelida: Polychaeta), Helobdella robusta (Annelida: Hirudinida), and Galathealinum brachiosum (Pogonophora: Perviata). The relative arrangements of all 22 genes identified for Helobdella and Galathealinum are identical to one another and to their arrangements in the mtDNA of the previously studied oligochaete annelid Lumbricus. In contrast, Platynereis differs from these taxa in the positions of several tRNA genes and in having two additional tRNA genes (trnC and trnM) and a large noncoding sequence in this region. Comparisons of relative gene arrangements and of the nucleotide and inferred amino acid sequences among these and other published taxa provide strong support for an annelid-mollusk clade that excludes arthropods, and for the inclusion of pogonophorans within Annelida, rather than giving them separate phylum status. Gene arrangement comparisons include the first use of a recently described method on previously unpublished data. Although a variety of alternative initiation codons are typically used by mitochondrial protein-encoding genes, ATG appears to be the initiator for all but one reported here. The large noncoding region (1,091 nt) identified in Platynereis has no significant sequence similarity to the noncoding region of Lumbricus, although each contains runs of TA dinucleotides and of homopolymers, which could potentially serve as signaling elements. There is strong bias for synonymous codon usage in Helobdella and especially in Galathealinum. In this latter taxon, 5 codons are completely unused, 13 are used three or fewer times, and G appears at third codon positions in only 26 of the 2,236 codons. Nucleotide composition bias appears to influence amino acid composition of the proteins.

Amino Acid Sequence↗
PubMed2001

On the origin of the Hirudinea and the demise of the Oligochaeta.

The phylogenetic relationships of the Clitellata were investigated with a data set of published and new complete 18S rRNA gene sequences of 51 species representing 41 families. Sequences were aligned on the basis of a secondary structure model and analysed with maximum parsimony and maximum likelihood. In contrast to the latter method, parsimony did not recover the monophyly of Clitellata. However, a close scrutiny of the data suggested a spurious attraction between some polychaetes and clitellates. As a rule, molecular trees are closely aligned with morphology-based phylogenies. Acanthobdellida and Euhirudinea were reconciled in their traditional Hirudinea clade and were included in the Oligochaeta with the Branchiobdellida via the Lumbriculidae as a possible link between the two assemblages. While the 18S gene yielded a meaningful historical signal for determining relationships within clitellates, the exact position of Hirudinea and Branchiobdellida within oligochaetes remained unresolved. The lack of phylogenetic signal is interpreted as evidence for a rapid radiation of these taxa. The placement of Clitellata within the Polychaeta remained unresolved. The biological reality of polytomies within annelids is suggested and supports the hypothesis of an extremely ancient radiation of polychaetes and emergence of clitellates.

Animals↗
PubMed2004

Nerve development, growth and differentiation during regeneration in Enchytraeus fragmentosus and Stylaria lacustris (Oligochaeta).

Enchytraeus fragmentosus (Enchytraeidae) and Stylaria lacustris (Naididae) are small terrestrial and limnetic oligochaetes that exclusively or seasonally reproduce by fragmentation and regeneration, respectively. We traced the neuronal development and differentiation during regeneration in order to gain information on the basic organization and evolution of the oligochaete nervous system. Subsequent to artificial amputation, the nervous systems have been stained with antibodies directed against acetylated alpha-tubulin. The staining was analyzed by indirect fluorescence in combination with confocal laser scanning microscopy. Both species show unique oligochaete neuronal regeneration patterns: (i) numerous fibers branch off from segmental nerves near the wound site and innervate the blastema; and (ii) the ventral cord is partly reestablished before the circumesophageal connectives develop. In the investigated 'Oligochaeta' the outgrowing fibers of the ventral nerve cord are soon bundled into at least two distinct connective pairs, which prolong into dorsal and ventral roots next to the mouth. Subsequent complete fusion of the doubled roots forms simple connectives. Thus, dorsal roots are not a unique feature for 'Polychaeta'. They occur as a transient structure in 'Oligochaeta' and might be part of the neuronal ground pattern of Annelida. The initially tetra or even pentaneuronal ventral nerve cord also differentiates into an unineuronal one by fusion.

Animals↗
PubMed1986

Features of glycogen phosphorylase from the body wall musculature of the lugworm Arenicola marina and the mode of activation during anoxia.

The activities of glycogen phosphorylases a and b from the body wall musculature of the marine worm Arenicola marina (Annelida, Polychaeta) were determined after various periods of anoxia. Already under normoxic conditions one third of the total activity was produced from the a form. During anoxia the ratio of both forms as well as the total activity did not change. The activity of soluble phosphorylase kinase was comparatively low in this tissue 4.3 +/- 1.2 nmol . min-1 . (g wet wt.)-1; the fast twitching tail muscle of shrimps, e.g., had a 10-fold higher phosphorylase kinase activity, whereas phosphorylase activities in both tissues were about the same 2.3 +/- 0.5 mumol . min-1 . (g wet wt.)-1. Glycogen phosphorylase b was purified from the body wall tissue of the marine worm in one step by 5'-AMP-Sepharose resulting in a single protein band in SDS-PAGE. This preparation was accepted as substrate by the phosphorylase kinase from rabbit muscle but a complete phosphorylation could not be achieved. The molecular mass of native phosphorylase was approximately 216 kDa, that of subunits 95 kDa indicating that the enzyme exists as a dimer. There were no isozymes in this preparation, the RF-value (0.17) of the single band in PAGE ranged between those of the isozymes from mice hearts. The activities of phosphorylases b and a were similarly dependent on pH and temperature but differed drastically in the affinities to phosphate and AMP. In presence of 1 mM AMP the app. Km of phosphorylase a for phosphate was 16 mM, that of phosphorylase b above 100 mM.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Monophosphate↗
PubMed2003

Changes in soft-bottom macrobenthic assemblages after a sulphuric acid spill in the Rio Grande Harbor (RS, Brazil).

The structure of macrobenthic assemblages in Rio Grande Harbor was analyzed during and after a sulphuric acid spill in August 1988. Five stations were sampled four times between September 1988 and March 1999. At each station, three samples were taken using a van Veen grab (0.078 m2). A total of 22 taxa were collected including Crustacea (9 spp.), Polychaeta (7 spp.), Mollusca (3 spp.), Phoronida (1 sp.), Nemertinea (1 sp.), and Plathyelminthea (1 sp.). The macrobenthic assemblages suffered different impacts depending on station location and time: 1) immediate impact, i.e., during acid discharge, as at the station nearest (250 m) the acid spill source; 2) impact some time after the discharge, as at the station 500 m downstream from the acid spill source; and 3) absence of direct impact on the remaining sampling points, on the discharge area outer limit. The macrobenthic assemblage recovered six months after the sulphuric acid spill.

Accidents↗
PubMed1997

Leech extracellular hemoglobin: two globin strains that are akin to vertebrate hemoglobin alpha and beta chains.

Leech (Whitmania edentula, Haemadipsa zeylanica var. japonica and Erpobdella lineata) extracellular hemoglobins are basically composed of three constituent subunits, a dimer (D1 and D2 chains) and two monomers (M1 and M2 chains). We isolated these four chains from respective species by a combination of reversed-phase chromatography on a Resource RPC column and gel-filtration on a Superdex 75 column. The apparent molecular masses of the four globin chains were estimated by SDS-PAGE analysis to be 13 kDa (M1), 16 kDa (M2; 19 kDa in its reduced form) and about 27 kDa for the dimer subunit (13 kDa for D1; 15 kDa for D2), regardless of the source. The amino (N)-terminal segments (21-30 residues) from twelve globin chains of the above three species were determined and aligned. It was found that the twelve sequences could be separated into two distinct globin groups A and B. This finding supports the original idea of "two globin strains in annelid hemoglobin", which was proposed without any evidence for leech hemoglobins. Comparing the sequences in the three classes of Annelida, Hirudinea, Oligochaeta and Polychaeta, we found two invariant amino acids, Cys and Trp, which are interposed by eleven amino acid residues. Furthermore, the globin chains belonging to strain A were readily discernible as they had three more invariants, Ser-13, Asp-16 and Trp-28, while the globin chains of strain B had two more invariants, Lys-12 and Arg-27. Consequently, we propose that each of the three classes of Annelida have two distinct groups of globin chains that are akin to vertebrate hemoglobin alpha and beta chains.

Amino Acid Sequence↗
PubMed1998

Field preservation of marine invertebrate tissue for DNA analyses.

Successful preservation of tissue samples is a prerequisite for long field studies in remote areas. However, there is little published information concerning field preservation of marine invertebrate tissues for DNA analyses. This omission is significant because marine biodiversity is centered in the Indo-Pacific, where immediate DNA analysis is often impossible. Consequently, we used an assay based on polymerase chain reaction (PCR) to examine the effect of five storage solutions and three temperature regimens on the degradation of DNA from four common classes of marine invertebrates (Anthozoa, Gastropoda, Polychaeta, and Scyphozoa). Control samples were cryopreserved. Storage solution and the type of tissue preserved were the best predictors of preservation success. The length of time in storage and the storage temperature also affected the preservation of DNA. A field test demonstrates that a solution of dimethylsulfoxide and sodium chloride (DMSO-NaCl) preserves a wide range of tissues for DNA analyses and is very simple to use in remote field locations.

Animals↗
PubMed2001

Abundance and distribution of small infauna in mangroves of Missionary Bay, north Queensland, Australia.

To assess the occurrence, spatial distribution and species composition of small infauna on a mangrove shore, core samples were taken along a transect in Missionary Bay at Hinchinbrook Island, north-east Australia. Three sites were arranged within the mangrove forest and one site was located in an adjacent mudflat. The sites were surveyed four times between November 1988 and October 1989. Based on the records from all samples and sites, 39 taxa were identified. Diversity (H') ranged from 1.18 to 2.38. Overall, total abundances of small infauna (retained on a 0.25 mm sieve) reached a mean value of 5,477 ind.m-2, with little variation throughout the transect or over time. Species numbers and diversity were higher in the mudflat than at the mangrove sites. The taxonomic composition changed between the mangrove forest and the mudflat: Oligochaeta were more abundant in mangrove sediments, whereas Polychaeta dominated in the mudflat. Of the polychaetes, Capitellidae were almost restricted to the mangrove sites, Sabellidae were recorded frequently at all sites, and Sigambra parva and Myriochele sp. were confined to the mudflat and the mangrove fringe. These species accounted also for dissimilarities between sites. Multivariate analyses showed a distinct assemblage at the mudflat compared to the mangrove sites. This survey showed that small infauna is an abundant component of mangrove sediments, which has been previously underestimated.

Animals↗