Luciola, Laporte, 1833, Laporte, 1833

Mori, Emiliano, Viviano, Andrea, Baratti, Mariella, Serafini, Elisa, Gabbrielli, Bianca, Picchi, Malayka Samantha, Giannetti, Daniele, Mascalchi, Cristina & Ancillotto, Leonardo, 2025, A light in the dark: DNA barcoding provides new data about the taxonomy of the Italian Luciola (Coleoptera, Lampyridae) fireflies, Zootaxa 5609 (4), pp. 525-536 : 529-530

Results

We successfully amplified 38 sequences of L. pedemontana , which corresponded to 20 haplotypes.In the phylogenetic tree ( Fig. 3 ) we found strong support for the existence of L. pedemontana as a well-supported clade, divergent from L. italica (mean genetic distance: 4.0%) and other firefly species (N = 40 sequences, N = 226 polymorphic sites, N = 97 parsimony informative sites, π = 0.04, haplotype diversity: 0.74). Conversely, this clade was weakly divergent from L. lusitanica (p: 2-3%). The ML and BI (shown) trees presented similar topologies, albeit different support values presented at each node ( Fig. 2 ). In particular, the node at the basis of L. italica and L. lusitanica+pedemontana Is highly supported by BI (=0.86) but weakly by ML analysis (100). Suggesting a not reliable separation. However, the support levels at the node sustaining the pedemontana group are robust for both inferences (0.92/95).

The haplotypes were analysed by the species delimitation criteria: results obtained by ABGD suggested 3 MOTUs, confirming the presence of a ‘barcode gap’ ( Fig. S 1 in Supplementary Material). The three species are L. pedemontana + L. lusitanica , L. italica and L. unmunsana + L. papariensis . These two last species, described as different taxa, show a low interspecific genetic distance (2%) and have been proposed as synonyms (cf. Jusoh et al. 2021). The PTP method identified five MOTUs within the Luciola genus, with the described species L. italica , L. lusitanica , L. unmunsana + L. papariensis and two taxa inside of L. pedemontana . ( Fig. S1 , Supplementary Material). The first taxonomic group inside pedemontana (1+ 3 in the Fig. 3 ) identified by PTP analyses for L. pedemontana is not highly supported in the phylogenetic tree (0.79/79) and comprises the subgroup 1 (Eastern) with specimens from Parma, Perugia, Siena, Grosseto, and Florence provinces and the subgroup from Padule di Bientina (Group 3, geographically and phylogenetically close to the Eastern group) one of the major wetlands in Tuscany located in the Pisa province; the Group 2 included Pisa, Massa Carrara, Siena, Grosseto and Florence provinces (Western), ( Fig. 3 ). The same group separation was also observed in the TCS network, where le distances among the three groups exceed the 90% of connection limit and they appeared as separated networks ( Fig. 4 ). The PTP method more sensible to small dataset and useful for taxonomic investigation is more coherent with the groups identified by phylogenetic analyses although not highly supported.

The genetic distances of the COI sequence between species ranged from 3.8% in average ( L. italica and L. pedemontana ) to 21% between the two genera Luciola and Lampyris species ( Table 2 ). The three L. pedemontana groups showed a genetic distance among them of around 2.8% that appears under the threshold found for intraspecific distances in Lampyridae . Intraspecific genetic distances ranged from 0.3% in Group 1to 1.1% for Group 2 ( Table 2 ).

Figures

FIGURE 1. Photos of A) L. pedemontana and B) L. Italica. A) authorized by Carlo Galletti B) authorized by Dr. Tomi Trilar Slovenian Museum of Natural History, Ljubljana, Slovenia.

FIGURE 2. A) Known distribution of L. italica and L. pedemontana in Italy (question marks mean unknown occurrence of both species: Fanti 2022); B) sampling sites: different colors indicate individuals from different COI groups as observable in Figure 1.

FIGURE 3. Phylogenetic BI tree inferred from COI sequences for the studied taxa. The nodal numbers are Bayesian Posterior Probabilities (BPP) and ML bootstrap values, respectively. Information for L. pedemontana sample used in this phylogenetic analysis (collection site, accession number) is reported in Table S1.

FIGURE 4. TCS parsimony network showing the relationships among Luciola pedemontana haplotypes. Circles represent different haplotypes. Circle size is proportional to the number of samples for each haplotype. Median vectors, which represent either extant unsampled or extinct ancestral sequences, are indicated by white circles.