Belarima violacea (Lucas) is an uncommon species of the Galerucini tribe (Coleoptera, Chrysomelidae, Galerucinae) distributed in Algeria, Morocco and Tunisia, and recorded here for the first time for the European fauna. One male and one female were found, not far from each other, wandering on the sand among the vegetation of the shifting dunes of the Tuscan coast (Rosignano Solvay, Spiagge Bianche). Some hypotheses are proposed to explain the presence of B. violacea on the Italian coast. Morphological descriptions of external habitus, aedeagus and spematheca, the latter here described for the first time, are also provided, accompanied by micro-photographs.

Belarima violacea, Chrysomelidae, Europe, Galerucinae, Galerucini, Italy, North Africa

Galerucinae are a large subfamily of Chrysomelidae, including about 15,000 species comprised in more than 1100 genera, of which more than 500 genera and about 8000 species in the tribe Alticini, and approximately 540 genera and 7200 species in the tribe Galerucini (Nadein and Bezděk 2014; Nie et al. 2017). Galerucini are widespread in all zoogeographic regions, and occur with 13 genera and 123 species in Europe (Beenen 2013, as Galerucinae).

The genus Belarima Reitter, 1913, with the species violacea (Lucas, 1847), is here recorded for the first time for the European fauna. Belarima currently includes two uncommon species: B. violacea from Algeria, Morocco and Tunisia, and B. obliqua Beenen, 2019, recently described from Algeria. This genus is separated from Arima Chapuis, 1875 by the absence of a basal pronotal margin, which in Arima is instead finely margined. In addition, Belarima shows some costae on the elytra, absent in Arima. Beenen (2019) instead considers Belarima as more related to Galeruca Geoffroy, 1762, because Arima has the sides of the abdominal tergites swollen while they are simple in Belarima, as in Galeruca. However, Belarima lacks the apical spurs on the tibiae, whereas they are present in Galeruca (Beenen 2019).

The specimens were examined, measured and dissected using a Leica M205C stereomicroscope. Photographs were taken using a Leica DFC500 camera and composed using Zerene Stacker version 1.04. Scanning electron micrographs were taken using a Hitachi TM-1000. Terminology follows D’Alessandro et al. (2016) for the median lobe of the aedeagus, and Bezděk (2015) and Rodrigues and Mermudes (2015) for the spermatheca. Geographical coordinates for the localities are reported in degrees, minutes and seconds (WGS84 format).

The occurrence of this North African species on the Tuscan coast is difficult to interpret. The possible hypotheses to explain these findings are essentially three:

1. relict population of a wider past distribution in the north-western Mediterranean. This hypothesis is rather unlikely, considering that other populations, in this case, would have had to survive in suitable areas of the Mediterranean. However, despite the intense research activity that has always involved this area, no other sites of occurrence of the species are known, excluding the North African ones;

2. occurrence due to passive anthropogenic transport between North Africa and this Tuscan locality. This hypothesis cannot be ruled out, although unlikely. The only sites close to the collecting locality that could constitute entry points for a possible passive anthropogenic introduction are the commercial port of Vada (distance 2.4 km S) and the tourist port of Cala de’ Medici (distance 1.6 km N);

3. possible colonization of the Tyrrhenian and Ligurian coasts through recent, or relatively recent, passive diffusion of this species from North Africa, vehiculated by assemblages of vegetal debris transported by the sea, possibly along the northern flow branch of the Algerian current. This marine current flows anticlockwise around the Tyrrhenian Sea along the coasts of Sicily and the Italian Peninsula before entering the Channel of Corsica (El-Geziry and Bryden 2010) (Fig. 1). Similar distributions due to possible vehiculation by Mediterranean marine currents have also been hypothesized for other species of Coleoptera (cf. Audisio et al. 2011).

Any hypothesis of active displacement can be excluded considering that the species is unable to fly. Future collecting in this Tuscan locality may provide information on the stability, or otherwise, of populations of B. violacea on the Italian coasts. In addition, new material would allow molecular analysis of the specimens and comparison with specimens from the North African populations, to evaluate their genetic distances.

We are grateful to our friend Ron Beenen (Nieuwegein, The Netherlands) for confirming the identification of Belarima violacea (Lucas) and support in preparing this contribution.