Graziella Mura

Animal xenodiversity in Italian inland waters: distribution, modes of arrival, and pathways

The paper provides a list of the non-indigenous animal species occurring today in Italian inland waters. Xenodiversity was found to amount to 112 species (64 invertebrates and 48 vertebrates), which contribute for about 2% to the inland-water fauna in Italy. Northern and central regions are most affected, and Asia, North America, and the rest of Europe are the main donor continents. The large majority of non-indigenous species entered Italy as a direct or indirect effect of human intervention. A difference between invertebrates and vertebrates was found for their mode of arrival (unintentional for invertebrates and intentional for vertebrates). Accidental transport, in association with both fish (for aquaculture or stock enhancement) and crops, has been the main vector of invertebrate introductions, whereas vertebrates were mostly released for stocking purposes. Overall stock enhancement (47.92%) and culture (37.5%) prevailed over the other pathways. Seventeen and 7 species of our list are included among the 100 worst invasive species of Europe (DAISIE) and of the world (IUCN), respectively. For some (but not all) non-indigenous species recorded in Italy the multilevel impact exerted on the recipient communities and ecosystems is known, even if rarely quantified, but knowledge on their chronic impact is still missing. Additional research is needed to provide criteria for prioritizing intervention against well established invaders and identify which new potential invader should be targeted as “unwanted”.

SEM morphological survey on the egg shell in the italian Anostracans (Crustacea, Branchiopoda)

The screening of the egg shell morphology of all italian species of Anostracans (14) by means of SEM, as well as the analysis of preliminary data on electrophoretical patterns of the adults, concerning the genus Chirocephalus (five species), suggest the need for a reconsideration, from a taxonomical point of view, especially as far as the species of the ‘diaphanus’ group (Ch. diaphanus, Ch. ruffoi, Ch. salinus, Ch. sibyllae) are concerned.In this light, within the above mentioned group remarkable differences have been observed for Ch. ruffoi, whilst for other species like Ch. diaphanus and Ch. sibyllae, conspecificity is suspected. Electrophoretical and reproductive isolation studies, in progress, will provide a clearer understanding of the actual situation.

Life history and interspecies relationships of Chirocephalus diaphanus Prévost and Tanymastix stagnalis (L.), (Crustacea, Anostraca) inhabiting a group of mountain ponds in Latium, Italy

Life histories of two coexisting Anostracan species, inhabiting a group of mountain ponds in Latium (Pantani di Forca Canapine) are described and discussed, with particular regard to hatching requirements, growth rate, fecundity and life span.Unlike previously assumed (Mura, 1985), the cysts of the two species Tanymastix stagnalis and Chirocephalus diaphanus seem to respond to the same hatching stimuli, since their nauplii coexist and can be separated by morphological differences.Significant differences recorded as to size, time in attaining sexual maturity, fecundity and life span, are in favour of a niche separation by size and by time. In particular, size differences are supposed to reflect significant differences also at filtering apparatus level, thus allowing prey selection by size.

Large-scale mitochondrial phylogeography in the halophilic fairy shrimp Phallocryptus spinosa (Milne-Edwards, 1840) (Branchiopoda: Anostraca)

Abstract.In this study we analyzed patterns of sequence divergence in about 1kb of mitochondrial DNA coding for two genes (16S rRNA and Cytochrome Oxidase I, COI) in 15 populations and 61 individuals of the halophilic fairy shrimp Phallocryptus spinosa (Milne-Edwards, 1840). Populations were sampled in saline and hypersaline water bodies from Spain, France, Italy, Greece, Turkey, Ukraine, Iran, Uzbekistan, Cyprus, Algeria, Morocco and Botswana. Our genetic findings suggest complex phylogeographic relationships and pronounced genetic differentiation among populations. Multiple phylogenetic methods and nested clade analysis revealed the existence of four highly divergent maternal lineages with strong phylogeographic patterns and signatures of either allopatric fragmentation or restricted gene flow with isolation by distance. These results are further supported by the hierarchical analysis of molecular variance (AMOVA) and pairwise FST values, which indicate that most of detected genetic heterogeneity is apportioned among populations. Genetic relationships among haplotypes fit geographical hypotheses in most cases but one. Indeed, one haplotype is shared among French, Iranian and Uzbekistan populations. We hypothesize that this peculiar occurrence might be due to an avian-mediated long distance passive dispersal event.

Current status of the Anostraca of Italy

Fairy shrimp distribution in Italy is updated on the basis of recent records . Their status is evaluated according to IUCN Red List criteria in order to document the current situation and to rectify previous incorrect assessments. Most of the 16 species have at least one population in a protected area, so that they apparently face little risk. Only Branchipus pasai and B. blanchardi are potentially threatened by future habitat alteration. It is stressed that data on fairy shrimp distribution are far from complete and limited to certain regions of the country. Their range reflects the specialist distribution and ‘migratory activity’ rather than that of the animals themselves.

Mitochondrial DNA Regionalism and Historical Demography in the Extant Populations of Chirocephalus kerkyrensis (Branchiopoda: Anostraca)

Background Mediterranean temporary water bodies are important reservoirs of biodiversity and host a unique assemblage of diapausing aquatic invertebrates. These environments are currently vanishing because of increasing human pressure. Chirocephalus kerkyrensis is a fairy shrimp typical of temporary water bodies in Mediterranean plain forests and has undergone a substantial decline in number of populations in recent years due to habitat loss. We assessed patterns of genetic connectivity and phylogeographic history in the seven extant populations of the species from Albania, Corfu Is. (Greece), Southern and Central Italy. Methodology/Principal Findings We analyzed sequence variation at two mitochondrial DNA genes (Cytochrome Oxidase I and 16s rRNA) in all the known populations of C. kerkyrensis. We used multiple phylogenetic, phylogeographic and coalescence-based approaches to assess connectivity and historical demography across the whole distribution range of the species. C. kerkyrensis is genetically subdivided into three main mitochondrial lineages; two of them are geographically localized (Corfu Is. and Central Italy) and one encompasses a wide geographic area (Albania and Southern Italy). Most of the detected genetic variation (≈81%) is apportioned among the aforementioned lineages. Conclusions/Significance Multiple analyses of mismatch distributions consistently supported both past demographic and spatial expansions with the former predating the latter; demographic expansions were consistently placed during interglacial warm phases of the Pleistocene while spatial expansions were restricted to cold periods. Coalescence methods revealed a scenario of past isolation with low levels of gene flow in line with what is already known for other co-distributed fairy shrimps and suggest drift as the prevailing force in promoting local divergence. We recommend that these evolutionary trajectories should be taken in proper consideration in any effort aimed at protecting Mediterranean temporary water bodies.

The life history of Chirocephalus kerkyrensis Pesta (Crustacea: Anostraca) in temporary waters of Circeo National Park (Latium, Italy)

The life cycle of Chirocephalus kerkyrensis, a typicalspecies of the Mediterranean plain forest, was studied in thefield during 1990/91 and 1991/92.Temperature, and its variation, was the major factor affectinglife history. Marked, sudden temperature fluctuations resultedin depressed growth and longevity. Fertility was positivelycorrelated (P<0.001) with female body length. Nodecline in egg production was observed at the end of life, incontrast to other species. Hatching was observed after a longdrought followed by alternating wet and dry phases. Laboratorytests on hatching gave contrasting results and showed thatdrying is not obligatory. Cysts stored in 100% relativehumidity gave higher numbers of nauplii after a shorter timethan dried ones, at all temperatures tested.

Molecular systematics and phylogeography in the fairy shrimp Tanymastix stagnalis based on mitochondrial DNA

Patterns of sequence divergence in about 1 kb of mitochondrial DNA coding for two genes (16s rRNA and cytochrome oxidase I, COI) were analysed in 13 populations of the fairy shrimp Tanymastix stagnalis from Norway, Germany, France, Italy (northern and central Italy plus insular populations from Sardinia and the Tuscan Archipelago) and Spain, and in one presumed population of Tanymastix stellae from Corsica. The latter species was originally known only from a single locality in Sardinia, which has been destroyed by urbanization; the Corsican population was referred to T. stellae by some French authors on the basis of the collection of several cysts from mud. mtDNA data revealed a very low level of genetic divergence between the presumed population of T. stellae and the other T. stagnalis populations included in the study. Our genetic findings do not support the presence of T. stellae in Corsica and are in line with previous SEM studies revealing that all species belonging to the genus Tanymastix produce cysts with identical morphology. The results indicate complex phylogeographic relationships and pronounced genetic differentiation among T. stagnalis populations. The islands of Corsica and Sardinia on the one hand and the island of Capraia (Tuscan Archipelago) on the other were probably colonized independently at different times. Genetic relationships among continental populations do not follow a clear geographical trend, indicating that geographical distance is not the main force shaping the pattern of genetic structuring of the species. Stochastic factors such as multiple and independent founder events probably contributed to the striking pattern of genetic differentiation along with subsequent local adaptation. These results agree with previously published molecular work on several groups of aquatic organisms and further support the high potential for dispersal–low gene flow paradox shown by a large array of animals living in lentic habitats.

The zooplankton crustacean of the temporary waterbodies of the Oasis of Palo (Rome, central Italy)

The WWF Oasis of Palo, 38 kms north of Rome, is one of the last remnants of the Mediterranean plain forest formerly covering the coastal areas of Latium. Within this preserved area, nine temporary waterbodies were periodically visited during 2001 to obtain information on their morphology, water cycle and faunal composition. In total, 25 crustacean species were listed and monthly changes in their abundance were recorded. Cladoceran species prevailed in all waterbodies (11 species, 7 genera, 2 families). Copepoda were represented by 8 species, 7 genera, 2 families. Ostracoda included 5 species, 5 genera, 3 families. Anostracans were recorded in only two pools and were represented by Chirocephalus diaphanus Prévost, 1803, the most common species in Italy. Chirocephalus kerkyrensis Pesta, 1936 usually occurring in the waterbodies of the Mediterranean maquis, was missing. Species richness was maximal in late autumn and winter, and correlated positively with pond duration, flooded area, water level and number of rainpools. The species most frequently recorded were Chydorus sphaericus O.F. Müller, 1785 and Daphnia curvirostris Eylmann, 1887 for Cladocera, Megacyclops viridis Jurine, 1820, Diacyclops bicuspidatus odessanus Shmankevitch, 1875 and Mixodiaptomus kupelwieseri Brehm, 1907 for Copepoda, Cyclocypris ovum Jurine, 1820 and Eucypris virens Jurine, 1820 for Ostracoda. Others, like Alona affinis Leydig, 1860, Ceriodaphnia pulchella Sars, 1862 (Cladocera), Macrocyclops albidus Jurine, 1820 (Copepoda), Herpetocypris reptans Baird, 1835 Fabaeformiscandona fabaeformis Fischer, 1854 (Ostracoda) were found in only one pool.

Morphological diversity of the resting eggs in the anostracan genus Chirocephalus (Crustacea, Branchiopoda)

Resting egg morphology of the species groups in Chirocephalus defined by Brtek (1995) on the basis of classical characters was examined by scanning electron microscopy (SEM) in order to verify this taxonomically useful character. The results are complex: some species groups show well delineated cyst morphology, but often not. Some species show rather constant morphologies, while in others, cyst ornamentation varies widely with and between populations.