The Italian agile frog (Rana latastei), also known as Lataste's frog, is a species of frog in the family Ranidae (true frogs). The species is native to southern Europe, primarily found in the Po River Basin of Italy. It is one of the most endangered amphibian species in Europe, with its populations declining sharply in recent years, and has been the focus of multiple conservation plans.
Etymology The specific name, latastei, is in honor of French herpetologist Fernand Lataste.
Description Rana latastei may attain a head-body length of 7.5 cm (3.0 in). Females tend to be slightly larger than males. Most frogs have pointed snouts, though rounded snouts have been observed in some individuals. Like many European common frogs, R. latastei is primarily gray or brownish-red with white bellies, with almost no color variation by geographic location. The throat is dark, with a light narrow central stripe that reaches down to the chest. Some sexually active males have dark red or brown spots on their throats, orange-red coloration on the underside of their thighs, and thumb pads on their forelimbs.
Habitat and distribution
Habitat R. latastei is a decidedly lowland species and rarely occurs above 400 m a. s. l., only going up to the lower foothills of mountains, where the colder climate delays larval development and metamorphosis. The Italian agile frog inhabits oak and hornbeam-dominated plain woods, hygrophilous woods and riparian woods characterized by white poplar and white willow trees. This types of woods may regularly be inundated by floods. It has also been reported from open habitats like wet meadows or peat bogs, as well as cottonwood plantations or ditches in agricultural areas that have sufficient vegetation. There have also been records of R. latastei living in caves in Italy and Croatia, though they may move between the caves and forests. Researchers have suggested the frogs were either washed into the cave by floods – which are fairly common in most habitats preferred by the Italian agile frog – or they intentionally moved to the caves to avoid predators, find food, or seek humidity. It is unknown whether the Italian agile frog breeds in these subterranean habitats. The Italian agile frog prefers humid regions with lots of rotting plant material and remains close to rivers, streams, lakes, and other sources of freshwater, which are required for the species' breeding and reproduction. They are most active early in the morning and at dusk and tend to avoid dry weather, during which the frogs will stay closer to sources of water and reduce activity until the evening. Adults are found closer to bodies of water during the breeding season between February and April, and are more commonly found in the forests when it becomes more humid during late spring and summer. Activity tends to be highest in the summer and early autumn once the spring breeding season has concluded. Hibernation on land begins in October, and frogs will emerge in the spring to breed.
Geographic distribution Rana latastei is endemic to the plains of northern Italy, the extreme southern tip of Switzerland, the Istrian region of Slovenia, and adjacent Croatia. In Italy, populations are reported from four regions: Lombardy, Venetia, Piedmont and Friuli-Venezia Giulia, but the species is most abundant in the former two. Its distribution mainly follows the Po River plains and tributaries.
Conservation The IUCN lists this species as Vulnerable (VU). A 2006 report indicated there were only about 250 populations of R. latastei in the wild, with western populations being smaller and at higher risk of extinction. The remaining 250 populations were small, isolated, and suffer from loss of genetic diversity. Major threats to the survival of the species include habitat destruction, degradation, and fragmentation, as it is highly adapted to the floodplain woods of the Po River basin.
Habitat loss Water pumping for crop irrigation has been especially harmful because it makes habitats less suitable for breeding. The Italian agile frog does not engage in long-distance movement and rarely strays far from the nearest breeding site, so fragmentation of forest habitats has also led to reduced genetic diversity among this species. This has been predicted to make the species more vulnerable to infection by Ranaviruses and other pathogens. Genetic isolation is also thought to cause significant variation in size between different populations of R. latastei. The introduction of invasive predatory species – including Percottuss glenii, the American bullfrog, and crayfish – have further endangered the Italian agile frog. The increased deposition of microplastics into the environment has also become a recent concern for the survival of the Italian agile frog. Tadpoles feed in an indiscriminate manner, which puts them at greater risk of ingesting these small plastic particles. Increased microplastic exposure has been associated with reduced growth, activity, and survival rates in R. latastei tadpoles. Smaller microplastic fragments have been associated with the strongest negative effects on the species. This may be because small pieces and fibers of plastic can form blockages and tangled clumps in the tadpoles' intestines. Some researchers have suggested that larger, more developed tadpoles are more resistant to the negative effects of microplastics on growth and activity. It is currently unknown how microplastics affect R. latastei adults.
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