A new species of Turbanellidae (Gastrotricha, Macrodasyida) from Jamaica, with a key to species of Paraturbanella

The study falls within the framework of a wider research programme aimed at investigating the gastrotrich diversity of the Tropical North-Western Atlantic (TNWA). A new macrodasyidan gastrotrich is described from fine-medium sand collected at Duncans Bay, Jamaica. The description is based on observations carried out on living specimens using differential interference contrast microscopy. Paraturbanella xaymacana sp. n., the third gastrotrich taxon reported from Jamaica, is a mid-sized species, up to 564 \u3bcm long, with a feeble peribuccal swelling. The most obvious autapomorphic traits pertain to the testes and the male pore, both of which are located approximately at mid body, rather than at- or near the pharyngo-intestinal junction as occur in the other species of the genus. Additional differences with congeners are discussed and a key to the Paraturbanella species is provided, in the hope it will be useful to both gastrotrich experts and marine ecologists who discover these microscopic metazoans during their research

Contribution of soft-bodied meiofaunal taxa to Italian marine biodiversity

Meiofauna includes an astonishing diversity of organisms, whose census is far from being complete. Most classic ecological studies have focused on hard-bodied Ecdysozoan taxa (notably Copepoda and Nematoda), whose cuticle allows determination at species-level after fixation, rather than soft-bodied, Spiralian taxa, which most often lose any diagnostic feature in fixed samples. Yet, metabarcoding studies have recently revealed a species-richness of softbodied taxa comparable, and in cases superior, to that of Copepoda and Nematoda together. However, given objective difficulties inherent to their study, which necessarily has to be performed on living individuals, and their limited utilisation for ecological and applicative research, taxonomic expertise on soft-bodied organisms has declined over the years, and diversity of these phyla in most areas of the world is presently completely unknown. Here we present an expert-based survey of current knowledge on the composition and distribution of soft-bodied meiofaunal taxa in Italy, with special references to the predominantly or exclusively meiobenthic phyla Gastrotricha, Gnathostomulida, Platyhelminthes, Rotifera, Xenacoelomorpha, and macrofaunal taxa with conspicuous meiofaunal representatives (Annelida, Mollusca and Nemertea). A total of 638 described species have been reported from Italian coasts; furthermore, the existence of a large number of undescribed species is mentioned. Knowledge of Annelida, Gastrotricha, and Rotifera appears particularly detailed, placing Italy among the best-known country worldwide. In contrast, knowledge of Platyhelminthes and Xenacoelomorpha appears patchy, and limited to few areas. Sampling effort has been uneven, with most species recorded from the Tyrrhenian Sea, while large sections of the Adriatic and Ionian seas have been poorly explored. Results highlight the role that Marine Biological Stations, notably the Zoological Station “Anton Dohrn” in Naples, have had in promoting the study of soft-bodied taxa in Ital

Fifteen species in one: deciphering the Brachionus plicatilis species complex (Rotifera, Monogononta) through DNA taxonomy

Understanding patterns and processes in biological diversity is a critical task given current and rapid environmental change. Such knowledge is even more essential when the taxa under consideration are important ecological and evolutionary models. One of these cases is the monogonont rotifer cryptic species complex Brachionus plicatilis, which is by far the most extensively studied group of rotifers, is widely used in aquaculture, and is known to host a large amount of unresolved diversity. Here we collate a dataset of previously available and newly generated sequences of COI and ITS1 for 1273 isolates of the B. plicatilis complex and apply three approaches in DNA taxonomy (i.e. ABGD, PTP, and GMYC) to identify and provide support for the existence of 15 species within the complex. We used these results to explore phylogenetic signal in morphometric and ecological traits, and to understand correlation among the traits using phylogenetic comparative models. Our results support niche conservatism for some traits (e.g. body length) and phylogenetic plasticity for others (e.g. genome size)

Status of Biodiversity in the Baltic Sea

The brackish Baltic Sea hosts species of various origins and environmental tolerances. These immigrated to the sea 10,000 to 15,000 years ago or have been introduced to the area over the relatively recent history of the system. The Baltic Sea has only one known endemic species. While information on some abiotic parameters extends back as long as five centuries and first quantitative snapshot data on biota (on exploited fish populations) originate generally from the same time, international coordination of research began in the early twentieth century. Continuous, annual Baltic Sea-wide long-term datasets on several organism groups (plankton, benthos, fish) are generally available since the mid-1950s. Based on a variety of available data sources (published papers, reports, grey literature, unpublished data), the Baltic Sea, incl. Kattegat, hosts altogether at least 6,065 species, including at least 1,700 phytoplankton, 442 phytobenthos, at least 1,199 zooplankton, at least 569 meiozoobenthos, 1,476 macrozoobenthos, at least 380 vertebrate parasites, about 200 fish, 3 seal, and 83 bird species. In general, but not in all organism groups, high sub-regional total species richness is associated with elevated salinity. Although in comparison with fully marine areas the Baltic Sea supports fewer species, several facets of the system's diversity remain underexplored to this day, such as micro-organisms, foraminiferans, meiobenthos and parasites. In the future, climate change and its interactions with multiple anthropogenic forcings are likely to have major impacts on the Baltic biodiversity

The muscular system of Musellifer delamarei (Renaud-Mornant, 1968) and other chaetonotidans with implications for the phylogeny and systematisation of the Paucitubulatina (Gastrotricha)

We studied comparatively the muscle organization of several gastrotrich species, aiming at shedding some light onthe evolutionary relationships among the taxa of the suborder Paucitubulatina. Under confocal laser scanningmicroscope, the circular muscles were present in the splanchnic position as incomplete circular rings in Muselliferdelamarei (Chaetonotidae) and Xenotrichula intermedia (Xenotrichulidae) and as dorsoventral bands in Xenotrichulapunctata, Heteroxenotrichula squamosa and Draculiciteria tesselata (Xenotrichulidae); in the somaticposition, M. delamarei shares the presence of dorsoventral muscles with all the Xenotrichulidae, in contrast withthe remaining Chaetonotidae that lack these muscles. Maximum parsimony analysis of the muscular charactersconfirmed monophyly of Paucitubulatina and Xenotrichulidae, while the Chaetonotidae was paraphyletic, with theexclusion of Musellifer, which is the most basal genus within the Paucitubulatina. Xenotrichulidae is the sistertaxon to Chaetonotidae, which in turn has Polymerurus as the most basal taxon. In general, the results agree withrecent phylogenetic inferences based on molecular characters and support the hypothesis that, within Paucitubulatina,dorsoventral muscles are plesiomorphies retained in marine, interstitial, hermaphroditic gastrotrichs.Dorsoventral muscles were subsequently lost during changes in lifestyle and reproduction modality that took placewith the invasion of the freshwater environment. This new information prompted us to reconsider the systematizationof Chaetonotidae, proposing the establishment of Muselliferidae fam. nov. to include the genera Muselliferand Diuronotus

Further data on the Italiana marine gastrotrich fauna.

This study reports on the gastrotrich fauna recorded in 14 new or newly investigated Italian locations, during surveys carried out from 2003-2005. As some of these unpublished faunistic data were included in the chapter devoted to Gastrotricha in the recent check-list of Italian marine species, this paper aims to provide details regarding the locations, people involved, sampling times, characteristics of the surveyed microhabitats and, of course, a list of species found at any single location. The research should be relevant as it provides the first lists of meiobenthic taxa from some protected Italian areas, such as “Area marina protetta di Porto Guaceto” and Asinara island. Other interesting locations, from a faunistic point of view, seem to be Cala Pisana, on the island of Lampedusa, where 16 species were recorded and Pomonte on the island of Elba, home to a dense population of lepidodasyid gastrotrichs that belong to an undescribed genus and species. Overall, it is hoped that the 40 species reported can contribute to debate on the biogeography of the Mediterranean gastrotrich

A new eye-bearing Macrodasys (Gastrotricha : Macrodasyida) from Jamaica

A new macrodasyidan gastrotrich is described from fine-medium sand collected at Doctor's cave beach of Montego Bay, Jamaica. Macrodasys ommatus n. sp. is the first gastrotrich to be reported from the Jamaica, the second described species in the genus to bear eye-spots and the . The shape of the frontal organ distinguishes the Jamaican species from its sibling M. nigrocellus: elongate and undulate without an accessory lateral chamber in the former vs. rather short with an accessory lateral chamber in the latter. The following combination of characters further distinguish the new species from its congeners: up to 7 anterior adhesive tubes per side arranged in a transversal row, three pairs of lateral adhesive tubes equally spaced along the intestinal region, up to 21 ventro-lateral adhesive tubes per side, two of which arise along the posterior region of the pharynx