Simone Cianfanelli

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”.

A tropical fish community in thermal waters of southern Tuscany

In a small stream of southern Tuscany (Fossa Calda), fed by hot springs, we discovered a fish community dominated by tropical species, some of which have never previously been reported in Euro-Mediterranean natural freshwater environments. The aim of our research was to ascertain whether the three most abundant and widespread species (Amatitlania nigrofasciata, Hemichromis sp. and Oreochromis niloticus) have become established. Analysis of size class distribution and growth curves showed that the populations of these species are quite large and made up of juveniles, subadults and adults, as is the case in self-sustaining populations. These fishes were probably released intentionally, since they are widely used in aquariums and aquaculture and their survival in Fossa Calda was possible because of the constant high temperature of thermal waters. Spread to other streams seems unlikely. In fact, at some distance from the hot springs, where water temperatures are lower, populations of the tropical species were small.

Litthabitella chilodia (Westerlund, 1886) in Italy (Gastropoda: Prosobranchia: Hydrobiidae)

Bythinella opaca pollinensis Bacci (1952) is herein regarded as a junior synonym of Litthabitella chilodia (Westerlund, 1886). Litthabitella Boeters, 1970, is a genus of hydrobiid prosobranchs characterized by: penis apex bifid, divided into apical lobe and tip of penis proper; one–four irregularly shaped glandular swellings on ventral side of apical lobe and penis close to base of lobe; well developed bursa copulatrix; two seminal receptacles, proximal (RS2) smaller than distal (RS1). At present it includes only the type species L. chilodia present in the western Balkans, Ionian islands and southern Italy. Paludinella elliptica Paladilhe, 1874, from the Pyrenees, once attributed to Litthabitella, still has uncertain taxonomic relationships. The current subdivision of L. chilodia into L. chilodia chilodia and L. chilodia ionica (Schütt, 1980) is rejected. Examination of the type material of the latter from the island of Corfu, showed that it includes two different taxa, one of which (the holotype) is a species of Belgrandia and the other L. chilodia. Due to the absence of anatomical data, the taxonomic status of Belgrandia ionica (Schütt, 1980) is still uncertain. Italian populations of L. chilodia are characterized by wide variation in shell shape and size and one population, living in a small brook in the cave Grotta del Tasso in Apulia, has two distinct coexisting shell morphs, almost without intermediates.