First European evidence for transcontinental dispersal of Crocodylus (late Neogene of southern Italy)

It is generally assumed that the Neogene crocodylian fauna of Europe has been represented only by brevirostrine alligatoroid Diplocynodon and longirostrine false gharials ( Gavialosuchus and/or Tomistoma ), which became extinct prior to 6 Mya. Although several lines of evidence suggest that Crocodylus originated in Africa during the Miocene and then promptly dispersed to other continents, the occurrence of this genus in Europe has never been rigorously proven and the traditional palaeontological approach failed to identify a monophyletic group of fossil Crocodylus (simply leading to a proliferation of extinct taxa). The new remains reported here, from an endemic insular fauna from southern Italy, Late Messinian to earliest Pliocene in age (5–6 million years old), represent the youngest European crocodylian, and allow, for the first time in a phylogenetic context, an unambiguous demonstration that Crocodylus dispersed into Europe, possibly during the Tortonian. If the peculiar morphology of the medial maxillary edge is interpreted as evidence for a medial dorsal boss, the southern Italian Crocodylus could be related to C. checchiai from the late Neogene of Libya. The presence of this African immigrant in Europe confirms the role of climate change for faunal dispersal and island colonization.  © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society , 2007, 149 , 293–307.     

THE REASSOCIATION KINETICS OF THE ILYANASSA GENOME

The reassociation kinetics of the genome of Ilyanassa obsoleta was measured by HAP chromatography and by optical methods. Eight kinetic components were found in total and nuclear DNA; the reassociation rate constant and analytical complexity was determined for seven of these components, and five components were isolated by HAP chromatography.     

Isolation and characterization of microsatellite loci to study parthenogenesis in the citrine forktail,Ischnura hastata (Odonata: Coenagrionidae)

The citrine forktail, Ischnura hastata, is an American damselfly species, widely distributed, with only‐female populations also found at the Azores islands. Here we report the development of nine microsatellite loci for this species. The number of alleles per locus ranged from six to 11, with an observed heterozygosity ranging from 0.245 to 0.737. Eight of the nine loci successfully amplified in a sample of parthenogenetic females from the Azores. The developed microsatellite system will be a useful tool to investigate population structure, as well as the number of clones, the type of parthenogenesis and the origin of the parthenogenetic populations of this species.     

Isolation and characterization of microsatellites in Zosterisessor ophiocephalus (Perciformes,Gobiidae)

We isolated and characterized 10 polymorphic microsatellite loci from two partial genomic libraries of Zosterisessor ophiocephalus (Perciformes, Gobiidae), enriched for AC and for multiple motifs. Variability was tested on specimens from the Venice lagoon revealing a high degree of genetic variation. The loci will be useful for monitoring the biodiversity of the species at the genetic level and for parentage assessment purposes.     

The Action of Fusicoccin Alone and with Some Plant Growth Substances on Tobacco Tissue Cultures

The interaction of fusicoccin, a terpenoid glucoside produced by Fusicoccum amygdali Del., and some plant growth regulating substances, i.e., indole-3-acetic acid, kinetin, 2,4-dichlorophenoxy-acetic acid and abscisic acid, was investigated on pith and sub-cultured callus cultures of Nicotiana tabacum L. Addition of fusicoccin alone to the basal medium, either in the light or in the dark, caused a fairly good development of tobacco callus. When fusicoccin and kinetin were simultaneously added to the culture medium, the callus growth increased. However, fusicoccin in combination with indole-3-acetic acid caused limited callus development: the tissue appeared brown and reduced in volume. Addition of fusicoccin with 2,4-dichlorophenoxyacetic acid stimulated growth of callus and chlorophyll was formed under light. Finally, abscisic acid did not interfere with the effect of fusicoccin on the callus growth.     

Trichomonas gallinae in wintering Common Wood Pigeons Columba palumbus in Spain

We studied the prevalence and potential subclinical effects of infestation by Trichomonas gallinae in 91 hunter-harvested Common Wood Pigeons Columba palumbus from northern ( n  = 30) and southern ( n  = 61) Spain during the winter period. All animals were measured, sexed, aged, necropsied and their organs were weighed. Infestation with T. gallinae was diagnosed using three different methods: direct inspection for the presence of lesions, direct microscopic observation and culture. Of the sampled birds, 34.2% were positive for the presence of T. gallinae . Prevalence was significantly higher in adult Wood Pigeons than in the juvenile group, and prevalence was significantly lower in birds sampled from the north. No significant differences in prevalence were found between males and females. Culture was significantly more sensitive than the other methods of diagnosis. Parasitized birds were in poorer body condition, as revealed by their lower body mass and fat reserves. No significant variation could be detected in heart or spleen weight between parasitized and healthy birds. However, juvenile Wood Pigeons in which T. gallinae was detected had a significantly larger bursa of Fabricius. Variations in the prevalence of T. gallinae in Wood Pigeons could be related to migration as well as increased exposure through shared feed and water where these are artificially provided. We also discuss the potential effect of T. gallinae on body condition and the eventual risk for endangered predators through increased exposure to infected prey.     

Does flooding affect spatiotemporal variation of fish assemblages in temperate floodplain wetlands?

1. Floodplain wetlands are productive components of lowland rivers and are thought to be important habitat and nurseries for many fish species. Fish assemblages inhabiting floodplain wetlands vary considerably through space and time and are largely shaped by wetting/drying cycles, although there is little understanding how many aspects of flooding (e.g. magnitude, timing, duration, frequency) influence the fish assemblages. As a consequence, decisions on flooding of wetlands by managers aimed at restoring native fish assemblages are often based on limited knowledge. 2. This study examined the importance of total duration of flooding on the temporal and spatial dynamics of wetland fish assemblages in the Murray River, in south‐eastern Australia. The study examined: (i) how the abundance of 0+ and 1+ fish varied with wetland, season and the duration of wetland filling; (ii) how environmental parameters, including food production changed in relation to the duration of wetland filling; (iii) changes in condition indices for the most abundant species and (iv) changes in species richness and total abundance over time. 3. The 0+ fish assemblage varied more through space and time than the 1+ assemblage. Longer cumulative river–wetland filling was associated with greater total abundances of newly recruited (0+) fish; this was particularly true for common carp (Cyprinus carpio, alien) and carp gudgeon (Hypseleotris spp., native). The body condition of carp gudgeon also increased with the duration of filling, even though static measures of food production declined. The small flooding events that occurred as part of this study did not translate into measurable improvements in the fish assemblage over the longer term (3 years), but did prevent wetlands from drying and thus maintained these habitats as refuges.     

Spatial patterns of the ant Crematogaster scutellaris in a model ecosystem

1. The spatial arrangement of individuals and populations may have deep influences on all the biotic interactions within a community. 2. The spatial distribution of nests of the ant Crematogaster scutellaris Olivier was analysed in an olive orchard in central Italy. As this species nests inside tree trunks, the regular structure of this simplified ecosystem may help to reduce the confounding effect of habitat heterogeneity on the spatial distribution of nests. In total, 531 trees were mapped and their shape (size and structure of the trunk) recorded. The presence of C. scutellaris nests in each tree was assessed in spring–summer and autumn 2006 and 2007. 3. The number of occupied trees changed in time, from a maximum of 129 (summer 2006) to a minimum of 60 (autumn 2007). Occupancy of tree was related to its shape, with larger trees being more frequently and more steadily occupied than smaller ones. 4. Nests were spatially aggregated, forming well‐defined clusters, but aggregation was not explained by a corresponding clumping of larger trees. Nests belonging to the same cluster were usually not aggressive to each other, whereas aggression was more common between nests belonging to different clusters. The dynamic nature of the system coupled with the clustered distribution of nests, is consistent with a hypothesis of seasonal polydomy, and suggest that whereas some trees are steadily occupied (core) others are opportunistically colonised when new resources are discovered (satellites). 5. Clusters size distribution was shown to follow a truncated power‐law, a finding consistent with the idea that clusters are self‐organised structures dependent on local interactions. These results suggest that spatial self‐organisation in ant colonies may in principle be more common than previously thought, although the mechanisms generating these patterns still need to be clarified.