New southernmost record of the European Brook Lamprey , Lampetra planeri ( Bloch , 1784 ) ( Agnatha , Petromyzontidae )

We report the occurrence of the European Brook Lamprey, Lampetra planeri (Bloch, 1784), in the Lao river in the Calabria region (southern Italy). This record extends the species’ known distribution limit southwards. Information regarding some morphometric and ecological data are provided and discussed.


Introduction
Of the 38 recognized lamprey species (Docker 2006), 4 have been reported for Italy: the European Brook Lamprey Lampetra planeri (Bloch, 1784), the River Lamprey Lampetra fluviatilis (Linnaeus, 1758), the Sea Lamprey Petromyzon marinus (Linnaeus, 1758), and the endemic Lombardy Brook Lamprey Lethenteron zanandreai (Vladykov, 1955).Lampetra planeri is a small lamprey, with adults ranging in size from 150 mm to 200 mm.It is a non-parasitic species that spends its life in freshwater (Hubbs and Potter 1971, Malmqvist 1980, Maitland and Campbell 1992).Because of population declines in several parts of Europe (Kappus et al. 1995), L. planeri is now given some legal protection in the European Union.In fact, it is listed in Annexes IIa and Va of the Habitats Directive (92/43/EEC) as a species whose conservation requires the designation of Special Areas of Conservation (SACs).The species is also included in the Appendix III of the Bern Convention, and it is considered as Vulnerable in the Red Data Book for fish in Italy (Ciuffardi and Tancioni 2016).For these reasons new information regarding its distribution, ecology, and biology is crucial and deserves particular interest.
Lampetra planeri occurs in streams and occasionally in lakes in northwest Europe and in Portugal.Its presence in Spain has not been confirmed (Waterstraat andKrappe 1998, Freyhof 2011).In Italy, it was originally reported throughout all of the Italian Peninsula on the side of the Tyrrhenian Sea as far south as Campania.A population has been also observed in the Pescara River on the Adriatic side of the peninsula.In Lazio, it has been detected in several secondary watercourses of the Tiber and Garigliano basins, as well as in other minor courses (Tancioni 1996, Tancioni and Cataudella 2009, Sarrocco et al. 2012).In Campania, L. planeri is well represented in the basins of the Bussento and Calore, and recently, a small residual population has been detected in the Mingardo (Bianco et al. 2011).A gradual decline over the past 26 years in the Umbrian basin of the Tiber, where it once was abundant, has been reported, and L. planeri is now thought to be almost extirpated there (Lorenzoni et al. 2010).
We report, for the first time, the occurrence of L. planeri in the Lao river, in northwestern Calabria (southern Italy).

Methods
We examined 18 specimens (2 adults and 16 ammocoetes) of European Brook Lamprey collected during field activity along the Lao river.Specimens were collected by electrofishing (SCUBLA 1300 W backpack electrofisher).Specimens were identified according to Hardisty (1986) and Kottelat and Freyhof (2007).All measurements were recorded with a digital caliper following Kucheryaviy et al. (2017).We released all specimens at the place of their collection.
We observed a density of about 10 larvae m −2 .Lampetra planeri was found in the lateral pools of the river where current was slow and the substratum sandy.This species was in sympatry with Anguilla anguilla Linnaeus, 1758, Sarmarutilus rubilio (Bonaparte, 1837), Squalius cephalus Linnaeus, 1758, and Salaria fluviatilis (Asso, 1801).Among them, only A. anguilla has been reported to be a natural predator of the ammocoetes of L. planeri (Maitland and Lyle 2000).

Discussion
Our finding represents not only the first documented record for the Calabria region, but also the new southernmost known and confirmed population of Lampetra planeri.These data suggest that the population of the Lao is in a good state of conservation and the contemporary presence of the adult phase and the larval phase testifies to its vitality (Maitland and Lyle 2000).This record confirms the richness in aquatic species of the Lao river system and of the Pollino National Park in general (Talarico et al. 2004, Bonacci et al. 2008).Further studies expanding into other Calabrian rivers are necessary to evaluate the actual presence of the European Brook Lamprey in this region.

Figure 1 .
Figure 1.Distribution map of Lampetra planeri.Red star represents the new record for the Lao river.

Figure 2 .
Figure 2. Specimens of Lampetra planeri.a. Adult (total length 170 mm).b.Oral disc of the adult (diameter 8.6 mm).c.Head and gill apparatus of the ammocoete (distance from the snout tip to the first gill opening 9.0 mm).