Maria Gallo

Meiofauna of the Adriatic Sea: present knowledge and future perspectives

Owing to technical problems and difficult taxonomic identification, meiofauna have been generally less studied than macrofauna. However, the role of meiofauna in marine ecosystem functioning, and their effective and rapid response to anthropogenic alterations and climatic changes have recently been acknowledged, leading to increasing scientific and applied interest. At present, systematic and biogeographic knowledge of the meiofauna of the Adriatic Sea is extremely heterogeneous, because most of the data are limited to a few taxa and the sampled areas are scattered, being located mainly in the coastal areas of the northern basin. Analysis of the composition and distribution of meiobenthic groups in the Adriatic Sea highlights the presence of several endemisms. Meiofauna also include bioindicator taxa, which allow assessment of the quality of marine sediments; this is particularly useful in systems characterised by the synergistic effect of different forms of anthropogenic impact, such as the Adriatic basin. Current knowledge about the ecology of the meiofauna and use of this component in applied ecological studies, along with the availability of a standardised protocol for the analysis of meiofaunal assemblages, allows us to recommend formal acknowledgement of the need to integrate information derived from the analysis of macrofauna with information derived from the study of meiofauna. Future research based on the simultaneous use of both of these benthic components will allow faster and more accurate evaluation of the response of coastal marine ecosystems to anthropogenic disturbance.

Adaptive radiation and phylogenesis in marine Tardigrada and the establishment of Neostygarctidae, a new family of Heterotardigrada

Abstract Adaptive radiation which has occurred in marine Tardigrada is discussed on the basis of the wide variety of species. The establishment of a new family, Neostygarctidae, is proposed and the hypothesis that two evolutive lines started from it is advanced. The possible affinities with other phyla are also discussed.

Marine Arthrotardigrada and Echiniscoidea (Tardigrada, Heterotardigrada) from the Indian Ocean

Abstract Three new species of marine Heterotardigrada, Arthrotardigrada and Echiniscoidea from a sandy shore of the Island of Mauritius, are described. They are two species of Stygarctidae: Parastygarctus renaudae and Stygarctus lambertii, and a species of Echiniscoididae: Anisonyches mauritianus. The evolution of the cephalic plate in P. renaudae during post‐embryonal development is somewhat peculiar. A. mauritianus has an evident medial cirrus and sense organs on the first three pairs of legs but both the clavae and the sense organs on the fourth pair of legs are indistinguishable.

Two new Mediterranean species of the genus Halechiniscus (Tardigrada, Heterotardigrada)

Abstract Halechinisats macroaphalus and H. paratuleari, two new species of marine Tardigrada (Heterotardigrada: Arthrotardigrada) are described from the Mediterranean. They display evident plesiomor‐phic characteristics such as large unpaired medial cirrus, cephalic region deeply divided in lobes and evident lateral processes. Furthermore, H. paratuleari shows the same arrangement of the cephalic cirri as do Stygarctidae. All these elements confirm the close relationship between Halechiniscidae, mainly Halechiniscinae, and Stygarctidae.