Polychaetes as bioindicators of environmental pollution: Impact of bisphenol A on the reproduction rate of Ophryotrocha diadema (Åkesson, 1976) (Eunicida: Dorvilleidae)

Bisphenol A (BPA) is one of the most used additives in the production of many plastic products and may be released into the environment by commonly used products, such as food containers and polycarbonate bottles. BPA is recognized as an endocrine disruptor able to produce adverse effects on the reproduction system of benthonic and pelagic species. Polychaetes of the genus Ophryotrocha are small worms living amongst the interstitial fauna in nutrient-rich and polluted habitats. Owing to easy rearing in the laboratory and short generation times, this species is a useful model organism for studying different biological aspects. This study describes the effects of different BPA concentrations on egg production in Ophryotrocha diadema. We tested six different concentrations of BPA in a 5-week experiment. Strong negative correlation between BPA concentrations and the number of eggs produced was found. The t-test revealed a significant reduction in egg production after exposure to BPA concentrations over 1461.1 μg/L. The latter concentration value is higher than that observed in the marine environment, although for many species of crustaceans, echinoderms and isopods, the impairment of reproductive function was observed even at much lower BPA concentrations.

An Introduction to the Study of Gastrotricha, with a Taxonomic Key to Families and Genera of the Group

Gastrotricha is a group of meiofaunal-sized, free-living invertebrates present in all aquatic ecosystems. The phylum includes over 860 species globally, of which 505 nominal species have been recorded in marine sandy sediments; another 355 taxa inhabit the freshwater environments, where they are recurrent members of the periphyton and epibenthos, and, to a lesser degree, of the plankton and interstitial fauna. Gastrotrichs are part of the permanent meiofauna and, in general, they rank among the top five groups for abundance within meiobenthic assemblages. The diversity, abundance, and ubiquity of Gastrotricha allow us to suppose an important role for these animals in aquatic ecosystems; however, ecological studies to prove this idea have been comparatively very few. This is mainly because the small size and transparency of their bodies make gastrotrichs difficult to discover in benthic samples; moreover, their contractility and fragility make their handling and morphological survey of the specimens rather difficult. Here we offer an overview, describe the basic techniques used to study these animals, and provide a key to known genera in an attempt to promote easy identification and to increase the number of researchers who may be interested in conducting studies on this understudied ecological group of microscopic organisms.

Ecology of Interstitial Faunal Assemblage from the Beaches along the Coast of Kerala, India

A quantitative and qualitative study of interstitial fauna and environmental variables was carried out on five selected sandy beaches of the west coast of India. Species of nine interstitial taxa abound the beaches. Nematodes, harpacticoid copepods, turbellarians, and polychaetes constituted the bulk of the population. The available energy in the beaches ranged from 0.2245 to 16.08 joules/mg and the grain size varied from 0.93 to 2.88φ. Organic matter correlated significantly with coarse sand (Pearson correlation r=0.651; P<0.01). Organic carbon, particle size, and dissolved oxygen determined the abundance and distribution of interstitial fauna as per multivariate BIOENV analysis. Shannon Wiener H′ diversity index was maximum at Cherai (2.027) and minimum at Sakthikulangara (1.144) beach. The value of nematode/copepod ratio (N (2A)/C>10) indicated at Sakthikulangara beach validates the increased sensitivity of harpacticoids to environmental stress.

Proposal of Fiersiphontina gen. nov., redescription of Fiersiphontina sensillata comb. nov., and new data on the distribution of Spiniferaphonte (Copepoda, Harpacticoida, Laophontidae)

The taxonomic position and original description of Laophontina sensillata Wells & Rao, 1987 are reviewed based on specimens collected from the interstitial fauna of littoral coral sands of several islands of the Philippines and New Caledonia, and the species is designated as the type species of Fiersiphontina gen. nov. The new genus is proposed based on the total loss of sexual dimorphism in the P3 and P4 exopods, and the sexual dimorphism in P2 exopod. Fiersiphontina is highly adapted to the littoral interstitial habitat of coral sandy beaches, and is related to Laophontina Norman & T. Scott, 1905, Wellsiphontina Fiers, 1991 and Spiniferaphonte Gheerardyn & Fiers, 2007. The shared characteristics that indicate a strong affinity of Fiersiphontina to Spiniferaphonte are the robust, dorsally bent, and strongly sclerotised caudal seta V and the morphology of the genital field. The phylogenetic relationship of Spiniferaphonte and Fiersiphontina is also suggested by the analysis of the last ontogenetic phases of the species of the two genera. We re-describe here the adults of both sexes, describe the last three copepodid stages of Fiersiphontina sensillata (Wells & Rao, 1987) comb. nov., and provide notes on the biogeography of the four related genera, and on the ecology of Fiersiphontina and Spiniferaphonte.

Symsagittifera smaragdina sp. nov.: A new acoel (Acoela: Acoelomorpha) from the Mediterranean Sea

From a survey of the interstitial fauna at Giglio, Italy, the new species Symsagittifera smaragdina sp. nov., (Sagittiferidae) is described. We herein transfer the genus Praesagittifera and its three species P. gracilis (Yamasu, 1982), P. naikaiensis (Yamasu, 1982), and P. shikoki Kostenko & Mamkaev, 1990 to the family Convolutidae. In addition the diagnosis for the family Sagittiferidae is revised to include only those species possessing sagittocysts in adult specimens.