Description of Marylynnia puncticaudata n. sp. (Nematoda, Cyatholaimidae) from Bizerte Lagoon, Tunisia

Descripción de Marylynnia puncticaudata sp. n. (Nematoda, Cyatholaimidae) del lago de Bizerta, Túnez Se describe morfológicamente una nueva especie de nematodo marino de vida libre de la familia Cyatholaimidae: Marylynnia puncticaudata sp. n. del lago de Bizerta (Túnez). Los machos se caracterizan por tener un cuerpo ligeramente más grande que las hembras, un anillo cefálico seguido de diez sedas subcefálicas, puntuación distinta de la cutícula, diferenciación laterocaudal de grandes puntos y gubernáculo muy cuticularizado con una forma única y la mitad distal bidenticulada. La ornamentación de la cutícula de las hembras es parecida a la de los machos. Sin embargo, su diferenciación laterocaudal se compone de puntos más pequeños y espaciados. Se ofrece una clave morfológica actualizada de la especie Marylynnia.A new free–living marine nematode species of Cyatholaimidae, Marylynnia puncticaudata n. sp. from Bizerte Lagoon (Tunisia) is morphologically described. Males are characterized by a slightly larger body than females, a cephalic ring followed by ten subcephalic setae, modified cuticular punctuation, caudal lateral differentiation of large dots, and strongly cuticularized gubernaculum with a unique shape and bidenticulated distal half. The cuticle ornamentation of females is similar to the males. However, their caudal lateral differentiation is composed of smaller and more spaced dots. An updated morphological key to species of Marylynnia is given.Descripción de Marylynnia puncticaudata sp. n. (Nematoda, Cyatholaimidae) del lago de Bizerta, Túnez Se describe morfológicamente una nueva especie de nematodo marino de vida libre de la familia Cyatholaimidae: Marylynnia puncticaudata sp. n. del lago de Bizerta (Túnez). Los machos se caracterizan por tener un cuerpo ligeramente más grande que las hembras, un anillo cefálico seguido de diez sedas subcefálicas, puntuación distinta de la cutícula, diferenciación laterocaudal de grandes puntos y gubernáculo muy cuticularizado con una forma única y la mitad distal bidenticulada. La ornamentación de la cutícula de las hembras es parecida a la de los machos. Sin embargo, su diferenciación laterocaudal se compone de puntos más pequeños y espaciados. Se ofrece una clave morfológica actualizada de la especie Marylynnia

Response of free-living Nematodes to the quality of water and sediment at Bou Chrara Lagoon (Tunisia) during winter 2000

The Bou Ghrara lagoon, a stretch of water in southeastern Tunisia, has shown an alarming reduction of its fishery resources since 1993. In order to study the response of free-living nematodes to the water and sediment quality of this area, thirteen stations have been sampled. According to this study, the heavy metal, organic carbon and hydrocarbon content of sediments are key factors negatively influencing the density, biomass and diversity of the nematofauna

Is the meiofauna a good indicator for climate change and anthropogenic impacts?

Our planet is changing, and one of the most pressing challenges facing the scientific community revolves around understanding how ecological communities respond to global changes. From coastal to deep-sea ecosystems, ecologists are exploring new areas of research to find model organisms that help predict the future of life on our planet. Among the different categories of organisms, meiofauna offer several advantages for the study of marine benthic ecosystems. This paper reviews the advances in the study of meiofauna with regard to climate change and anthropogenic impacts. Four taxonomic groups are valuable for predicting global changes: foraminifers (especially calcareous forms), nematodes, copepods and ostracods. Environmental variables are fundamental in the interpretation of meiofaunal patterns and multistressor experiments are more informative than single stressor ones, revealing complex ecological and biological interactions. Global change has a general negative effect on meiofauna, with important consequences on benthic food webs. However, some meiofaunal species can be favoured by the extreme conditions induced by global change, as they can exhibit remarkable physiological adaptations. This review highlights the need to incorporate studies on taxonomy, genetics and function of meiofaunal taxa into global change impact research

Description of Marylynnia puncticaudata n. sp. (Nematoda, Cyatholaimidae) from Bizerte Lagoon, Tunisia

A new free–living marine nematode species of Cyatholaimidae, Marylynnia puncticaudata n. sp. from Bizerte Lagoon (Tunisia) is morphologically described. Males are characterized by a slightly larger body than females, a cephalic ring followed by ten subcephalic setae, modified cuticular punctuation, caudal lateral differentiation of large dots, and strongly cuticularized gubernaculum with a unique shape and bidenticulated distal half. The cuticle ornamentation of females is similar to the males. However, their caudal lateral differentiation is composed of smaller and more spaced dots. An updated morphological key to species of Marylynnia is given

Marine Nematode Taxonomy in Africa: Promising Prospects Against Scarcity of Information

From the late 19th century, Africa has faced heavy exploitation of its natural resources with increasing land/water pollution, and several described species have already become extinct or close to extinction. This could also be the case for marine nematodes, which are the most abundant and diverse benthic group in marine sediments, and play major roles in ecosystem functioning. Compared to Europe and North America, only a handful of investigations on marine nematodes have been conducted to date in Africa. This is due to the scarcity of experienced taxonomists, absence of identification guides, as well as local appropriate infrastructures. A pivotal project has started recently between nematologists from Africa (Tunisia), India, and Europe (Italy) to promote taxonomic study and biodiversity estimation of marine nematodes in the African continent. To do this, as a first step, collection of permanent slides of marine nematodes (235 nominal species and 14 new to science but not yet described) was recently established at the Faculty of Sciences of Bizerte (Tunisia). Capacity building of next generation of African taxonomists have been carried out at level of both traditional and molecular taxonomy (DNA barcoding and next-generation sequencing [NGS]), but they need to be implemented. Indeed, the integration of these two approaches appears crucial to overcome lack of information on the taxonomy, ecology, and biodiversity of marine nematodes from African coastal waters

Diuron environmental levels effects on marine nematodes: Assessment of ecological indices, taxonomic diversity, and functional traits

Coastal marine systems are the most sensitive zones to emerging pollutants. The present study aims to investigate the effect of Diuron on the meiofaunal assemblages, collected from the Bizerte channel (Tunisia). Microcosm experiments were set up using four increasing Diuron concentrations [D1 (10 ng g−1 dry weight (DW)), D2 (50 ng g−1 DW), D3 (250 ng g−1 DW) and (1250 ng g−1 DW)] compared to non-contaminated sediments (controls) and all plots were incubated for 30 days. Our results show that Diuron-supplemented sediments provoked the significant decrease of meiofaunal abundance as well as a change in nematodes' diversity and structure composition. All univariate indices, as well as the cumulative k-dominance, were lower in the Diuron than the control plot. Additionally, the ordination of treatments according to the two-dimensional nMDS plots analysis showed a clear structural separation of the Diuron treated replicates from the controls based on the functional groups lists. These current data emphasize the utility of the use of biological traits in the detection of disturbances in the aquatic biotope

Nutzen und Grenzen von Modellökosystemen zur Erfassung der Wirkung von Schadstoffen auf benthische Lebensgemeinschaften

Brinke M, Höss S, Traunspurger W, Heininger P. Nutzen und Grenzen von Modellökosystemen zur Erfassung der Wirkung von Schadstoffen auf benthische Lebensgemeinschaften. Umweltwiss Schadst Forsch. 2009;21(3):248-251