Genetic evidence of two sibling species within the Contracoecum ogmorhini Johnson & Mawson 1941 complex (Nematoda; Anisakidae) from otariid seals in boreal and austral regions

Genetic variation of Contracaecum ogmorhini (sensu lato) populations from different otariid seals of the northern and southern hemisphere was studied on the basis of 18 enzyme loci as well as preliminary sequence analysis of the mitochondrial cyt b gene (260 bp). Samples were collected from Zalophus californianus in the boreal region and from Arctocephalus pusillus pusillus, A. pusillus doriferus and A. australis from the austral region. Marked genetic heterogeneity was found between C. ogmorhini (sensu lato) samples from the boreal and austral region, respectively. Two loci (Mdh-2 and NADHdh) showed fixed differences and a further three loci (Iddh, Mdh-1 and 6Pgdh) were highly differentiated between boreal and austral samples. Their average genetic distance was DNei = 0.36 at isozyme level. At mitochondrial DNA level, an average proportion of nucleotide substitution of 3.7% was observed. These findings support the existence of two distinct sibling species, for which the names C. ogmorhini (sensu stricto) and C. margolisi n. sp., respectively, for the austral and boreal taxon, are proposed. A description for C. margolisi n. sp. is provided. No diagnostic morphological characters have so far been detected; on the other hand, two enzyme loci, Mdh-2 and NADHdh, fully diagnostic between the two species, can be used for the routine identification of males, females and larval stages. Mirounga leonina was found to host C. ogmorhini (s.s.) inmixed infections with C. osculatum (s.l.) (of which C. ogmorhini (s.l.) was in the past considered to be a synonym) and C. miroungae; no hybrid genotypes were found,confirming the reproductive isolation of these three anisakid species. The hosts and geographical range so far recorded for C. margolisi n. sp. and C. ogmorhini (s.s.) are given

visita presso Università di Norwich school Biological Sciences, con congedo "per eccezionali e giustificate ragioni di ricerca e di studio dal 01.01.2006 al 21.12.2006" ai sensi dell'art.10 della legge 18 marzo 1958 n.311 per compiere studi e ricerche su "SPECIAZIONE E GENETICA ECOLOGICA IN ORCIHDEE EUROPEE

Analysis by molecular markers of speciation by hybridization in tetraploid marsh orchids of genus Dactylorhiza. Demonstration of Ecological speciation in the diploid marsh orchid Dactylorhiza incarnata, with particular regard to british and irish populations living in different habitats. Conservation ecology of endangered Dactylorhiza orchids, with characterization of evolutionary significant units (ESU).24 novembre 200

Bio-functional diversity of Cymodocea nodosa as bioindicator for environmental quality in the lakes of Circeo National Park (Italy)

In this research we evaluated the bio-functional diversity of Cymodocea nodosa populations by RAPD technique in two of the lakes of Circeo National Park (Caprolace and Fogliano). The ecological structure of the meadows was followed during the year 2004: physicochemical parameters were measured in conjunction with seagrass phenological parameters A high degree of genotypic homogeneity of the seagrass, confirmed by statistical analysis (NT-SYS Cluster), was observed in association to a high vegetative continued growth via rhizome extention. In this investigation we confirm that a high nutrient concentration, in water and sediment, determines a high density and biomass values of meadow. Other environmental factors, such as temperature, salinity and light, are important in controlling seasonal biomass and abundance of C. nodosa in these lakes. Finally different modes of reproduction, such as continued growth, via rhizome extension, into new locations and sexual offspring (seedling) recruitment, may contribute to low differentiation in the seagrass C. nodosa that can be considered as biological indicators for environmental quality in lagoon ecosystems