Polychaete

ABSTRACT This study compares the feeding guild composition of macrobenthic (infaunal) polychaetes from two different transects (Cheyyur and Singarayakonda) situated in the continental shelf region of southeast coast of India. The polychaetes collected from these transects were identified using standard manuals [Fauvel P. 1953. The fauna of India including Pakistan, Ceylon, Burma and Malaya: Annelida, Polychaeta. Allahabad: The Indian Press Ltd; 507 p.; Day JH. 1967. A monograph of the polychaeta of southern Africa. London: British Museum (Natural History Museum) Publication; 878 p.]. The total number of species recorded from the study area was 75 belonging to 54 genera and 29 families. These species were categorized into various feeding types following Fauchald and Jumars [Fauchald K, Jumars PA. 1979. The diet of worms: a study of polychaete feeding guilds. Oceanography and Marine Biology: Annual Review 17: 193–284] and confirmed after examination of mouthparts. Among these, 34 species (45.3%) were found to be surface deposit feeders, 25 species (33.3%) carnivores, 8 species (10.7%) subsurface deposit feeders, 5 species (6.7%) filter feeders and 3 species (4%) were omnivores. A total of 1330 polychaetes were collected, with 65% representing surface deposit feeders, 31% carnivores, 3% filter feeders and less than 1% were subsurface deposit feeders and omnivores. The sediment was sandy in Cheyyur and silty overall in Singarayakonda. Although the surface deposit feeders were dominant [72.97% with higher Margalef richness (d) value of 2.27 ^ 1.56 and Simpson richness (12 l0) value of 0.72 ^ 0.36] in Cheyyur, carnivores were dominant (48.36% with higher richness values of d – 1.52 ^ 0.82 and 1 2 l0 – 0.80 ^ 0.11) in Singarayakonda transect. The distance-based linear model showed the influence of median particle diameter (explained 24.7% of total variability), depth (19.1%) and total organic carbon (16.2%) on the distribution of feeding guild composition of polychaetes, indicating that the co-variables strongly differentiate the feeding guild composition of polychaetes in the two transects.

Four myzostomidan species were collected during a survey of echinoderms made on the Great Reef of Toliara, southwest Madagascar. The four species were associated with comatulid crinoids. Notopharyngoides aruensis infested the anterior part of the digestive lumen of Stephanometra indica. Comanthussp. aff.wahlbergiiwere infested by three myzostomidan species, two of them are new to science. Myzostoma polycyclus and Myzostoma pseudocuniculus n. sp. lived at the surface of crinoids. Myzostoma toliarense n. sp. live in soft cysts induced on crinoid arms. Cysts are always located close to the ambulacral grooves. They are each infested by one myzostomid.

Silver nanoparticles (AgNPs) offer a broad range of high commercial value applications. However, current techniques to synthesize AgNPs using chemical and physical approaches are toxic to the environment and not cost-effective in the long-term. Therefore, utilization of green biological synthesis technique to produce AgNPs is one of the solutions. In this study, marine polychaete Diopatra claparedii was used to investigate its potential in synthesizing AgNPs. Specimens were collected from tidal flats adjacent to the mangrove forest in the west coast of Peninsular Malaysia and divided into two groups: freshly prepared (acclimatized in aquaria) and frozen (kept in the freezer) samples. Samples from both groups were cut, finely pulverized, filtrated, and mixed with silver nitrate (AgNO3) at room temperature. Colour changes were recorded after 24 hours, 2 weeks, and 8 weeks of incubation. Formation of AgNPs was quantified using UV-Vis spectroscopy analysis, where surface Plasmon resonance (SPR) peaks were observed in the range of 400–440 nm, confirming the formation of the AgNPs. Subsequently, the synthesized nanoparticles were validated using scanning electron microscope. AgNPs showed weak antibacterial activity because of aggregation. Further studies are required to confirm the findings.

Ceratonereis (Composetia) burmensis Monro (1937) is reported for the first time from Pakistan. A single specimen was collected from Hab river delta (24°53'13.45'' N and 66°42'18.04'' E) on the Balochistan coast in September, 2017. Two species of Ceratonereis previously reported from Pakistan are: Ceratonereis marmorata (Horst, 1924) and Ceratonereis sp. (Cpmposetia) burmensis differs from C. marmorata in having a prostomium that is not marmorated. It also differs from Ceratonereis sp. in having neuropodial falcigers. C. (Composetia) burmensis has wide distribution from Iran to China.

Three new species of Magelona are described from the Seychelles: M. conversa, M. falcifera and M. gemmata. Magelona conversa belongs to a 'M. mirabilisgroup', having a rounded prostomium and specialised chaetae on chaetiger 9, but differs from all other members in having long prechaetal neuropodial lamellae on chaetigers 1–8. Magelona falcifera bears large sickle-shaped hooded hooks in the abdomen and thus approaches the genus Meredithia, but lacks prostomial horns. Magelona gemmata belongs to a 'M. longicornis group' in having distinct prostomial frontal horns, and a thorax with lanceolate postchaetal lamellae in the notopodia and ventral neuropodial lobes. The distinctively swollen bud-like tips on the notopodial lamellae of chaetiger 9 are an unique feature. The status of MeredithiaHernández-Alcántara & Solís-Weiss, 2000 and current magelonid terminology are discussed.