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Article

First Insights into the Mitochondrial DNA Diversity of the Italian Sea-Slater Across the Strait of Sicily

by
Francesco Paolo Faraone
1,†,
Luca Vecchioni
1,*,†,
Arnold Sciberras
2,
Antonella Di Gangi
3 and
Alan Deidun
4
1
Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Via Archirafi 18, 90123 Palermo, Italy
2
The Exterminator, Service Hub, Triq San Gorg, 5 In-Naxxar, NXR 2541 Naxxar, Malta
3
Associazione Berta Maris, via Mannarazza, 92031 Linosa, Italy
4
Oceanography Malta Research Group, Department of Geosciences, Faculty of Science, University of Malta, MSD 2080 Msida, Malta
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Diversity 2025, 17(9), 622; https://doi.org/10.3390/d17090622
Submission received: 7 August 2025 / Revised: 1 September 2025 / Accepted: 3 September 2025 / Published: 4 September 2025
(This article belongs to the Special Issue Marine Nearshore Biodiversity—2nd Edition)
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Versions Notes

Abstract

The Strait of Sicily represents a biogeographically rich and complex region. The diverse geological origin and past continental connection of its islands have shaped a highly heterogeneous fauna, mainly composed of both African and European taxa. The Italian sea-slater, Ligia italica (Fabricius, 1798), is a small isopod inhabiting rocky shores of the Mediterranean Sea, Black Sea, and Atlantic Ocean. Despite its wide distribution, the phylogeography of this species is poorly understood, with limited available data suggesting a remarkable level of cryptic diversity. In this study, we investigated the mitochondrial genetic diversity (COX1) of L. italica across nine Italian and Maltese islands across the Strait of Sicily, aiming to clarify the biogeographic patterns underlying the distribution of these insular populations. Our results reveal an unexpectedly high genetic diversity within our study area, with eight different haplogroups, each characterized by low internal genetic variation and mutual distances ranging from 5.5% to 17.9%. These values are comparable to those associated with species-level rank within the genus Ligia. Overall, the phylogenetic relationships between the lineages appear well supported; however, the same relationships are not clearly correlated with geographic proximity or connectivity among the sampled localities. The distribution patterns of some of the detected haplogroups suggest possible passive dispersal mechanisms (e.g., rafting), while others indicate more intricate biogeographic scenarios. The overall diversity of L. italica within the Strait of Sicily, as well as the unclear origin of some insular populations, cannot be fully explained with the current data. In particular, the high genetic structure observed within the Maltese Archipelago, may partially reflect human-mediated dispersal (e.g., maritime transport), possibly involving source populations that remain unsampled or genetically uncharacterized. Our results highlight that the Strait of Sicily can be considered a diversity hot spot for L. italica and support the designation of this taxon as a putative species complex, with a cryptic diversity worthy of an exhaustive taxonomic revision.

1. Introduction

The genus Ligia (Fabricius, 1798) includes over 50 species of isopods with a cosmopolitan distribution [1,2,3]. This group is notable for its highly restricted habitat, which is largely confined to the uppermost reaches of the intertidal zone along rocky shores [4], equivalent to the mediolittoral and lower supralittoral zone in microtidal seas like the Mediterranean. In these restricted biotopes, sea-slaters complete their entire life cycle, feeding on algae or scavenging for dead organisms [5]. Unlike other semiterrestrial coastal crustaceans with a planktonic larval stage [6,7,8], the developmental stages of sea-slaters occur in brood sacs, carried by females, and after birth the juveniles share the same habitat with adults [9]. Many sea-slaters species dive into rock pools to escape predators and to rehydrate [10]. However, sea-slaters are unable to remain submerged for extended periods and must surface to breathe. At the same time, they cannot stray far from water sources, wave-splash zones or moist crevices as they rapidly dehydrate [11,12].
The extreme specialization of their ecological niche, combined with the absence of a planktonic larval stage, results in a very limited dispersal ability [11]. Consequently, these isopods are highly susceptible to population fragmentation caused by the emergence of barriers such as sandy shorelines or episodes of marine transgression, such as flooding [13]. The unique ecological adaptations of the genus Ligia, along with the recurrent occurrence of allopatric conditions over evolutionary time, have disrupted gene flow between populations, promoting genetic diversification and speciation phenomena [13,14]. For these reasons, this taxon is currently considered an ideal model for investigating evolutionary processes through a biomolecular approach, as highlighted by recent studies revealing extensive cryptic diversity within its species [14,15,16,17].
The Italian sea-slater Ligia italica, Fabricius, 1798, exhibits a wide distribution that includes the coasts of the Mediterranean Sea, Black Sea, and Atlantic Ocean, including Macaronesia, Cape Verde, Morocco, and Western Sahara coasts [1,3]. Despite its wide range, the phylogeographic structure of this species remains poorly understood. Nonetheless, the few studies addressing its genetic variability have revealed substantial cryptic diversity, such as the two deeply divergent clades identified among Tunisian populations [17].
The Strait of Sicily and its islands represent a complex system of great biogeographic interest. The diverse geological origin, their intermittent connections with the mainland, and the intricate surface water circulation in the area [18] have shaped a remarkably diverse native fauna. This fauna includes a mixture of taxa of African [19,20,21] and European [22,23] origin, as well as a high rate of endemism [24,25,26]. Moreover, the central Mediterranean has been subject to intense anthropogenic influence, both ancient and modern, which has further shaped the current biodiversity of its islands through numerous biotic introductions [27,28].
Here, we investigated the mitochondrial genetic diversity of Ligia italica across several Italian and Maltese islands of the Strait of Sicily, including the Maltese Archipelago, the Aegadian Islands, the Pelagian Islands, and Pantelleria, aiming to assess the biogeographical pattern that led to the formation of these isolated populations. For this purpose, we also included comparative data from the mainland boundaries of this area, including novel generated sequences from Sicily and already published data from Tunisia [17]. Furthermore, in order to explore within-island genetic variation, we genetically characterized multiple populations sampled along the coasts of the main Maltese islands.

2. Materials and Methods

Between 2024 and 2025, we sampled 19 localities distributed across seven different islands within three Sicilian Strait archipelagos (Maltese, Pelagian, and Aegadian) and four localities along the southern and northern coasts of Sicily. Additional samples were collected in previous years from the island of Pantelleria and from two further localities in northwestern Sicily. The sampling sites are listed in Table 1 and mapped in Figure 1, produced with QGIS v. 3.30.2 [29].
Sampling was conducted on rocky shores inhabited by Ligia italica (Figure 2). Sea-slaters were captured by hand or with forceps, if hidden in rocky crevices, and immediately preserved in 96% alcohol.
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Figure 1. Distribution of Ligia italica samples collected in Sicily (Italy) and Malta. Squares and circles indicate published [17] and novel sample sites, respectively. Different colours refer to the different clades reported in Figure 3. See Table 1 for the coordinates of the sampled sites. Map created using the Free and Open Source QGIS software v. 3.30.2.
Figure 1. Distribution of Ligia italica samples collected in Sicily (Italy) and Malta. Squares and circles indicate published [17] and novel sample sites, respectively. Different colours refer to the different clades reported in Figure 3. See Table 1 for the coordinates of the sampled sites. Map created using the Free and Open Source QGIS software v. 3.30.2.
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Figure 2. Habitats sampled in some study areas: (A) Malta, Marsaxlokk; (B) Comino; (C) Gozo, Dwejra; (D) Marettimo, Scugghiazzu; (E) Sicily, Capo d’Orlando; (F) Sicily, Licata.
Figure 2. Habitats sampled in some study areas: (A) Malta, Marsaxlokk; (B) Comino; (C) Gozo, Dwejra; (D) Marettimo, Scugghiazzu; (E) Sicily, Capo d’Orlando; (F) Sicily, Licata.
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Figure 3. Bayesian phylogram of the studied Ligia italica samples based on the mtDNA I dataset. Ligia oceanica (Linnaeus, 1767) was used as an outgroup to root the tree. Node supports are reported as posterior probabilities (BI)/bootstrap values (ML). Asterisks indicate support values lower than 50. Square brackets group samples according to their current taxonomy. Letters A–H identify the main clades discussed in the text. The analyzed specimens are reported using the GenBank accession numbers listed in Table 1 and the ISO 3166-1 alpha-3 code for the country. Novel sequences are reported in bold.
Figure 3. Bayesian phylogram of the studied Ligia italica samples based on the mtDNA I dataset. Ligia oceanica (Linnaeus, 1767) was used as an outgroup to root the tree. Node supports are reported as posterior probabilities (BI)/bootstrap values (ML). Asterisks indicate support values lower than 50. Square brackets group samples according to their current taxonomy. Letters A–H identify the main clades discussed in the text. The analyzed specimens are reported using the GenBank accession numbers listed in Table 1 and the ISO 3166-1 alpha-3 code for the country. Novel sequences are reported in bold.
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One to four specimens (65 individual in total) were selected from each population for DNA extraction. A single leg was excised from each specimen and subsequently soaked in distilled water for 5 min to remove any residual ethanol. DNA extraction was then carried out using the BIORON GmbH “Ron’s Tissue DNA Mini Kit”, following the manufacturer’s standard protocol.
The selective amplification of the mitochondrial gene encoding Cytochrome c oxidase subunit 1 (COX1) was carried out by the polymerase chain reaction (PCR) using the primers LCO1490 and HCO2198 [30]. The PCR mix consisted of 19.3 μL of distilled water, 2.5 μL of Buffer 10X which includes 20 mM of MgCl2, 0.3 μL of dNTPs (10 mM for each), 0.3 μL of each of the primers (10 μM), 0.3 μL of Taq polymerase (5 U/μL) and 2 μL of template DNA, for a total volume of 25 μL. The thermal cycle consisted of 35 cycles of denaturation (94 °C for 45 s), annealing (45 °C for 45 s) and extension (72 °C for 1 min), followed by 7 min at 72 °C for the final extension step.
After PCR amplification, 4 μL of each PCR product was loaded onto a 1% agarose gel pre-stained with ethidium bromide and subjected to electrophoresis at 90 V for 25 min. DNA fragments were visualized under a UV transilluminator, and only products showing a clear single band of the expected size were purified using the Exo-SAP-IT® kit (Affymetrix USB, Cleveland, OH, USA). Purified amplicons were then sent for sequencing to Macrogen Europe (Italy) on an ABI 3130xl genetic analyser (Applied Biosystems, Carlsbad, CA, USA). The same primer pairs used for PCR were employed for direct sequencing. Sequence quality was evaluated based on Phred scores [31], and only sequences with continuous stretches of high-quality bases (QV > 20) were retained for subsequent analyses. Resulting chromatograms were inspected and manually curated using MEGA12 software [32].
Novel sequences were deposited in GenBank (see Table 1 for their Accession Numbers, A.N.’s). Furthermore, aiming to compare the novel produced COX1 sequences with a selection of those publicly available, 27 Ligia italica COX1 sequences (including one sequence for each known haplotype of the species) and a sequence of L. oceanica (Linnaeus, 1767) (used as an outgroup) were downloaded from GenBank and included in the analyses. All COX1 sequences were aligned with MEGA12 software through the ClustalW method. All analyzed COX1 sequences were translated into amino acids to check for any possible presence of frameshifts or stop codons, eventually highlighting the presence of sequencing errors or pseudogenes. The uncorrected p-distance values among COX1 sequences were calculated using MEGA12.
Based on available sequences, two datasets were built. The first one included COX1 Ligia italica sequences only from the study area (“mtDNA I dataset”). This allowed to include 73 sequences, i.e., the Tunisian specimens investigated in the literature (see [17]), the novel ones investigated in the present study and the outgroup. A second dataset included all the COX1 sequences available on GenBank (“mtDNA II dataset”—see Figure S1).
For all datasets phylogenetic relationships were inferred using the software packages MrBayes v. 3.2.7 [33] and PhyML v. 3.0 [34], employing Bayesian Inference (BI) and Maximum Likelihood (ML) approaches, respectively. Node support was assessed by calculating bootstrap values (BS) with 1000 replicates for the ML trees, while posterior probability values (PP) were reported for the BI trees. For each marker, the optimal evolutionary model was determined from those available by MrBayes, using the Bayesian model choice criteria (nst = mixed, rates = invgamma) and subsequently applied in the ML analysis. The best-fit model for all datasets was identified as the General Time-Reversible model of sequence evolution with a proportion of invariable sites and gamma-distributed rate variation among sites (GTR + I + Γ).
In the BI analyses, two independent Markov chain Monte Carlo analyses were carried out for 1,000,000 generations (temp.: 0.2; default priors) with sampling every 1000 generations, the first 2500 trees were discarded as a burn-in process and a consensus tree was constructed (Effective Sample Size (ESS) greater than 200 was reached in all the analyses performed).

3. Results

Overall, 50 COX1 novel Ligia italica sequences were produced. After aligning novel and GenBank sequences, as well as trimming the tails which were not present in all the specimens, we obtained a 590 bp COX1 fragment (for both mtDNA datasets). Moreover, no stop codons were detected through the translation of the novel and published COX1 sequences into amino acids.
The BI and ML trees based on the mtDNA I dataset, overall, showed eight well-supported haplogroups clustering the sequences based on their geographical origin (Figure 1 and Figure 3): (A) Maltese Archipelago (northern coasts); (B) Maltese Archipelago (eastern coasts); (C) Sicily (south-eastern coast); (D) Maltese Archipelago (western coasts); (E) Lampedusa island; (F) Sicily (northern coasts); (G); Tunisia (southern coast); (H) Tunisia (northern coast), Aegadian islands (Marettimo and Favignana), Pantelleria island, Linosa island, Sicily (southern coasts). In contrast, the BI and ML trees based on the mtDNA II dataset showed a topology which was less congruent with the mtDNA I results. Haplogroups A-H from the study area appeared with lower support and several polytomies, suggesting a more unresolved pattern when compared with the broader dataset available (Figure S1). The mean uncorrected p-distance values within and between haplogroups are reported in Table 2.

4. Discussion

Our results highlight an unexpectedly high genetic diversity and phylogenetic structure within the study area (Figure 3). We found eight distinct haplogroups (i.e., A–H, see Figure 3 and Table 1) with low internal diversity and high divergence between them (Table 2). The distances between haplogroups, ranging from 5.5% to 17.9% (Table 2), are at the higher end of the reported range comparable to those assigned to a specific rank within the genus Ligia [17,35,36], while their average within-groups distance is 0.8%. This finding further supports the interpretation of L. italica as a putative species complex [17], harbouring cryptic diversity worthy of taxonomic revision. Similar complex patterns of hyperdiversity have also been documented in other arthropods typical of Mediterranean coastal shores and intertidal zones as Coleoptera and Copepoda [37,38,39,40].
The sea-slater populations of the Maltese archipelago present an unexpectedly complex phylogeographic condition. Three different haplogroups (A, B, D) were identified, exhibiting with very high mutual genetic distances ranging between 13.2% and 16.1% (Table 2). The three lineages have a paraphyletic condition, with no sister relationships (Figure 3). No cases of mixed population were identified and their distribution in the archipelago is apparently parapatric (Figure 1), with the sole exception of a single sample of haplogroup A (A.N., PX239620), which represented the only specimen observed along the entire 160 m concrete dock of the Birżebbuġa Marina, which falls within the range of haplogroup B (Figure 1). The isolation and unsuitable habitat (e.g., lack of shelters and pools) of this single sample suggests that it may have been unintentionally introduced via “shipping” (see [41]) from the range of haplogroup A.
The origin and relationships of the Maltese Ligia italica populations are very difficult to interpret, based on our results. Although Malta has a rather complex geological history [42], which likely influenced the origin and distribution of its native fauna [24,43,44], vicariance events within the archipelago are currently not supported for L. italica, due to the evident paraphyletic relationships between haplogroups A, B, and D (Figure 3 and Figure S1); this condition could suggest a mixture of colonization processes from different sources. Furthermore, active dispersal events from the Hyblaean Plateau (southeastern Sicily) during Pleistocene marine regression occurrences are unlikely, due to the weakly supported relationships between the Maltese haplogroup B and the closer “mainland” one C (Figure 3 and Figure S1). In addition, the hypothesis of passive dispersion via rafting is difficult to apply since the Maltese archipelago is at the centre of a complex surface circulation, affected by the Malta-Sicily anticyclonic gyre to the north, and by the Medina cyclonic gyre to the south [45]. Similarly, origin through several introduction events (e.g., by shipping) cannot currently be ruled out, due to the limited knowledge of genetic variation within L. italica across its entire range, which could hide possible sources of translocation. Greater sampling coverage could, in fact, further clarify the relationships between populations and further identify the causes and drivers of recent dispersal events, both natural and human-mediated.
Haplogroup E includes sequences obtained from two localities on the island of Lampedusa (Table 1, Figure 1). It presents consistent mean uncorrected p-distance values with respect to the other groups (9–17%, Table 2) and sister relationships with haplogroup D (western cliffs of the Maltese Archipelago), with the latter haplotype location directly facing the island of Lampedusa, albeit at an approximate distance of 110 km. Thus, unexpectedly, the populations of Ligia italica from Lampedusa do not appear to have direct phylogenetic relationships with those of the geographically closest Tunisian mainland (G and H haplogroups). Lampedusa and Tunisia, in fact, share the same continental shelf and were connected by land bridges during the Pleistocene intermittent marine regressions [46]; this has shaped, on the island, a unique faunal assemblage largely of North African origin [47,48]. Furthermore, Lampedusa is affected (similarly to the small islands of the H lineage) by a superficial marine circulation that would favour a passive dispersal of L. italica from the coasts of North Africa [45]. These factors do not support a hypothesized long-term isolation of this population as well as the phylogenetic relationships that emerge from our analysis. Therefore, they deserve to be explored further by increasing sampling coverage in the wider central Mediterranean area, to more precisely define the origin, affinities and possible source of the haplogroup D.
Haplogroup H is the most widespread in our study area, including samples from northern Tunisia [17], much of the southern coast of Sicily, the Aegadian archipelago and the volcanic islands of Linosa (Pelagian Archipelago) and Pantelleria (Figure 1 and Figure 3). Low internal variability (mean uncorrected p-distance < 1%; Table 2), a poor geographic structure and the sharing of haplotypes between allopatric populations (Figure 1) are observed inside this group, despite its wide distribution and the occurrence of many potential barriers between populations. Haplogroup H, in fact, occurs on isolated (open-water) islands (i.e., Pantelleria and Linosa), and along the predominantly sandy coast of southern Sicily [49] between Torretta Granitola and the western part of the Gulf of Gela (Figure 1), where Ligia italica has a fragmented distribution along a few scattered rocky shores, factors that should increase diversity by interrupting gene flow (see [13]). In a genus known for its poor dispersal ability and high intraspecific variability [13,14,17], it is difficult to interpret a monophyletic unit that combines a wide and fragmented distribution and a low internal variability. However, it cannot be ruled out that the occurrence of passive dispersion may play a role in the distribution and internal gene flow of haplogroup H, thus diluting any putative internal genetic variation that may arise. In particular, rafting is known as one of the main processes that can maintain connectivity within coastal species under allopatric conditions [50,51]; this was also often hypothesized for sea-slaters [41,52,53]. The sea surface circulation across the Strait of Sicily, described by Reyes-Suarez et al. [45], suggests that rafting events could be favoured by the Atlantic Ionian Stream (Tunisia to the Aegadian islands and to southern Sicily), as well as by the Atlantic Tunisian Current (Tunisia to Pantelleria and Linosa). Similarly, haplogroup F, which encompasses samples from the northern Sicilian coast and presents phylogenetic relationships with the Southern Tunisian (G haplogroup) [17] and the H haplogroup, may have been influenced by the Atlantic/Algerian bifurcation current.
The genetic variation in Ligia italica across the southern coasts of Sicily is not solely represented by haplogroup H. The southeastern area is in fact affected by haplogroup C (Figure 1), phylogenetically unrelated to H (Figure 3), from which it presents a significant genetic distance (17.5%) (see Table 2). This result suggests, once again, a non-obvious relationship between diversity and geographic proximity. Our sampling coverage does not allow us to precisely establish the geographical limits between haplogroups C and H, furthermore, the actual extension of the former haplogroup deserves further investigation. Given the limited data available on L. italica in this area, it is currently difficult to explain the possible factors that determined its diversity. It could be influenced by vicariance phenomena, given the particular geological history of the Hyblaean Plateau and its fauna [20,23,54], as well as by dispersal, given the peculiar pattern of surface marine circulation that affects this area [45].
Overall, our findings do not reveal unambiguous patterns of dispersal, isolation, or differentiation across the Strait of Sicily. Instead, they point to a highly complex biogeographic scenario, likely shaped by multiple, independent factors. While the phylogenetic relationships among lineages within the study area are generally well supported (Figure 3), these relationships do not appear to correspond clearly to geographic distance or to connectivity between localities. These discrepancies, along with a reduced clarity in phylogenetic relationships, become more pronounced when Ligia italica sequences available from other areas are included in the analysis (Figure S1). This likely reflects the high degree of genetic diversity within the species, combined with the incomplete and geographically scattered nature of the available dataset across the distribution range of L. italica.

5. Conclusions

In conclusion, the remarkable cryptic diversity that emerges amongst the Italian sea-slater populations (see also [17]) emphasizes the need to expand sampling and genetic investigation across its entire geographic range in order to acquire a better understanding of their evolutionary relationships between the identified haplotypes. To further explore its taxonomy, it will also be necessary to compare populations using additional genetic markers (e.g., nuclear DNA) and by assessing any variation detected at the molecular level through an examination of morphological traits too.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/d17090622/s1, Figure S1: Bayesian phylogram based on the mtDNA II dataset. Ligia oceanica (Linnaeus, 1767) was used as an outgroup to root the tree. Node supports are reported as posterior probabilities (BI)/bootstrap values (ML). Asterisks indicate support values lower than 50. Square brackets group samples according to their current taxonomy. The analyzed specimens are reported using the GenBank accession numbers listed in Table 1 and the ISO 3166-1 alpha-3 code for the country. Novel sequences are reported in bold.

Author Contributions

Conceptualisation, F.P.F., L.V. and A.D.; methodology, F.P.F., L.V., A.S., A.D.G. and A.D.; validation, F.P.F. and L.V.; formal analysis, F.P.F. and L.V.; writing—original draft preparation, F.P.F. and L.V.; writing—review and editing, F.P.F., L.V., A.S., A.D.G. and A.D. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Data Availability Statement

The data presented in this study are available in GenBank at https://www.ncbi.nlm.nih.gov/genbank/, accessed on 28 August 2025 (COI A.N.’s: PX239605-PX239654).

Acknowledgments

We thank Alessio Marrone for his precious help in the laboratory activities. Jeffrey Sciberras and Gina Curmi are acknowledged for their assistance during the filed activities.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Boyko, C.B.; Campos-Filho, I.S.; Hadfield, K.A.; Hughes, T.; Merrin, K.L.; Ota, Y.; Poore, G.C.B. World List of Marine, Freshwater and Terrestrial Isopod Crustaceans Database. Available online: https://www.marinespecies.org/isopoda/ (accessed on 6 August 2025).
  2. Schmalfuss, H. Terrestrial Isopods (Crustacea: Isopoda) from the Caucasus Region. 5. Cylisticus Schnitzler, Parcylisticus Verhoeff, Cylisticoides n. gen. Stuttg. Beitr. Zur Naturkunde Ser. A 2003, 647, 1–38. [Google Scholar]
  3. Vandel, A. Isopodes Terrestres (Première Partie); Faune de France; Lechevalier P: Paris, France, 1960; Volume 64. [Google Scholar]
  4. Edney, E.B. Woodlice and the Land Habitat. Biol. Rev. 1954, 29, 185–219. [Google Scholar] [CrossRef]
  5. Morris, R.H.; Abbott, D.P.; Haderlie, E.C. Intertidal Invertebrates of California; Stanford University Press: Stanford, CA, USA, 1980. [Google Scholar]
  6. Schiller, C.; Fielder, D.R.; Brown, I.W.; Obed, A. Reproduction, Early Life-History and Recruitment. In The Coconut Crab: Aspects of Birgus latro Biology and Ecology in Vanuatu; Brown, I.W., Fielder, D.R., Eds.; ACIAR Monograph 8: Canberra, Australia, 1991; pp. 13–15. [Google Scholar]
  7. Lucrezi, S.; Schlacher, T.A. The Ecology of Ghost Crabs. Oceanogr. Mar. Biol. Annu. Rev. 2014, 52, 201–256. [Google Scholar] [CrossRef]
  8. Vecchioni, L.; Marrone, F.; Deidun, A.; Adepo-Gourene, B.; Froglia, C.; Sciberras, A.; Bariche, M.; Burak, A.Ç.; Foka-Corsini, M.; Arculeo, M. DNA Taxonomy Confirms the Identity of the Widely-Disjunct Mediterranean and Atlantic Populations of the Tufted Ghost Crab Ocypode cursor (Crustacea: Decapoda: Ocypodidae). Zool. Sci. 2019, 36, 322–329. [Google Scholar] [CrossRef]
  9. Warburg, M.R. Evolutionary Biology of Land Isopods; Springer: Berlin/Heidelberg, Germany, 1993. [Google Scholar] [CrossRef]
  10. Zhang, P.; Sun, J.; Wang, S.; He, D.; Zhao, L. Influences of Desiccation, Submergence, and Salinity Change on Survival of Ligia cinerascens (Crustacea, Isopoda): High Potential Implication for Inland Migration and Colonization. Hydrobiologia 2016, 772, 277–285. [Google Scholar] [CrossRef]
  11. Carefoot, T.H.; Taylor, B.E. Ligia: A Prototypal Terrestrial Isopod. In Crustacean Issues 9: Terrestrial Isopod Biology; Scharam, F.R., Balkema, A.A., Eds.; Routledge: London, UK, 1995; pp. 40–70. [Google Scholar]
  12. Tsai, M.-L.; Dai, C.F.; Chen, H.-C. Desiccation Resistance of Two Semiterrestrial Isopods, Ligia exotica and Ligia taiwanensis (Crustacea) in Taiwan. Biochem. Physiol. 1998, 119, 361–367. [Google Scholar] [CrossRef]
  13. Hurtado, L.A.; Mateos, M.; Santamaria, C.A. Phylogeography of Supralittoral Rocky Intertidal Ligia Isopods in the Pacific Region from Central California to Central Mexico. PLoS ONE 2010, 5, e11633. [Google Scholar] [CrossRef]
  14. Santamaria, C.A. Molecular Taxonomy of Endemic Coastal Ligia Isopods from the Hawaiian Islands: Re-Description of L. hawaiensis and Description of Seven Novel Cryptic Species. PeerJ 2019, 7, e7531. [Google Scholar] [CrossRef]
  15. Santamaria, C.A.; Mateos, M.; Taiti, S.; DeWitt, T.J.; Hurtado, L.A. A Complex Evolutionary History in a Remote Archipelago: Phylogeography and Morphometrics of the Hawaiian Endemic Ligia Isopods. PLoS ONE 2013, 8, e85199. [Google Scholar] [CrossRef]
  16. Greenan, T.M.; Griffiths, C.L.; Santamaria, C.A. Molecular Approaches Uncover Cryptic Diversity in Intertidal Ligia Isopods (Crustacea, Isopoda, Ligiidae) across the Southern Africa Coastline. PeerJ 2018, 6, e4658. [Google Scholar] [CrossRef]
  17. Laifi-Necibi, N.; Amor, N.; Merella, P.; Mohammed, O.B.; Medini, L. DNA Barcoding Reveals Cryptic Species in the Sea Slater Ligia italica (Crustacea, Isopoda) from Tunisia. Mitochondrial DNA A DNA Mapp. Seq. Anal. 2025, 35, 1–11. [Google Scholar] [CrossRef]
  18. UNEP-MAP-RAC/SPA. Sicily Channel/Tunisian Plateau: Topography, Circulation and Their Effects on Biological Components; Würtz, M., Cebrian, D., Requena, S., Eds.; RAC/SPA: Tunis, Tunisia, 2015. [Google Scholar]
  19. Guariento, L.A.; Devincenzo, U.; Schifani, E.; Russo, R.; Moretto, E.; Sarà, M. Rediscovery of the Enigmatic Solifuges (Arachnida: Solifugae) at Lampedusa Island (Italy). Eur. Zool. J. 2018, 85, 201–209. [Google Scholar] [CrossRef]
  20. Colomba, M.; Lo Verde, G.; Liberto, F.; Gregorini, A.; Sparacio, I. Molecular and Biometric Data on Carabus (Macrothorax) morbillosus Fabricius, 1792 (Coleoptera, Carabidae) from Mid Mediterranean Areas. Zookeys 2022, 2022, 119–134. [Google Scholar] [CrossRef]
  21. Faraone, F.P.; Melfi, R.; Di Nicola, M.R.; Giacalone, G.; Lo Valvo, M. The Genetic Identity of the Only Italian Population of the Genus Macroprotodon Guichenot, 1850 on the Island of Lampedusa, Sicily. Vertebr. Zool. 2020, 70, 235–240. [Google Scholar] [CrossRef]
  22. Senczuk, G.; Harris, D.J.; Castiglia, R.; Litsi Mizan, V.; Colangelo, P.; Canestrelli, D.; Salvi, D. Evolutionary and Demographic Correlates of Pleistocene Coastline Changes in the Sicilian Wall Lizard Podarcis wagleriana. J. Biogeogr. 2019, 46, 224–237. [Google Scholar] [CrossRef]
  23. Schifani, E.; Prebus, M.M.; Alicata, A. Integrating Morphology with Phylogenomics to Describe Four Island Endemic Species of Temnothorax from Sicily and Malta (Hymenoptera, Formicidae). Eur. J. Taxon. 2022, 833, 143–179. [Google Scholar] [CrossRef]
  24. Thake, M.A. The Biogeography of the Maltese Islands, Illustrated by the Clausiliidae. J. Biogeogr. 1985, 12, 269–287. [Google Scholar] [CrossRef]
  25. Muscarella, C.; Baragona, A. The Endemic Fauna of the Sicilian Islands. Biodivers. J. 2017, 8, 249–278. [Google Scholar]
  26. Sparacio, I.; Muscarella, C.; Di Giulio, A.; Ruzzier, E. Description of a New Rhizotrogus Latreille, 1825 (Scarabaeidae, Melolonthinae), from the Island of Pantelleria (Sicily Channel, Italy). Biodivers. Data J. 2025, 13, e154423. [Google Scholar] [CrossRef]
  27. Nardi, G.; Mifsud, D. The Bostrichidae of the Maltese Islands (Coleoptera). Zookeys 2015, 481, 69–108. [Google Scholar] [CrossRef]
  28. Papežík, P.; Sciberras, A.; Benovics, M.; Sciberras, J.; Deidun, A.; Mikulíček, P. Far from Home: Tracing the Origin of Non-Native Water Frogs (Genus Pelophylax) in Malta by Molecular Markers. Biol. Invasions 2024, 26, 1045–1059. [Google Scholar] [CrossRef]
  29. QGIS Development Team QGIS Geographic Information System. Open-Source Geospatial Foundation Project. Available online: http://www.qgis.org/ (accessed on 6 August 2025).
  30. Folmer, O.; Black, M.; Hoeh, W.; Lutz, R.; Vrijenhoek, R. DNA Primers for Amplification of Mitochondrial Cytochrome c Oxidase Subunit 1 from Diverse Metazoan Invertebrates. Mol. Mar. Biol. Biotechnol. 1994, 3, 294–299. [Google Scholar]
  31. Richterich, P. Estimation of Errors in “Raw” DNA Sequences: A Validation Study. Genome Res. 1998, 8, 251–259. [Google Scholar] [CrossRef]
  32. Kumar, S.; Stecher, G.; Suleski, M.; Sanderford, M.; Sharma, S.; Tamura, K. MEGA12: Molecular Evolutionary Genetic Analysis Version 12 for Adaptive and Green Computing. Mol. Biol. Evol. 2024, 41, msae263. [Google Scholar] [CrossRef]
  33. Ronquist, F.; Teslenko, M.; Van Der Mark, P.; Ayres, D.L.; Darling, A.; Höhna, S.; Larget, B.; Liu, L.; Suchard, M.A.; Huelsenbeck, J.P. Mrbayes 3.2: Efficient Bayesian Phylogenetic Inference and Model Choice across a Large Model Space. Syst. Biol. 2012, 61, 539–542. [Google Scholar] [CrossRef]
  34. Guindon, S.; Dufayard, J.F.; Lefort, V.; Anisimova, M.; Hordijk, W.; Gascuel, O. New Algorithms and Methods to Estimate Maximum-Likelihood Phylogenies: Assessing the Performance of PhyML 3.0. Syst. Biol. 2010, 59, 307–321. [Google Scholar] [CrossRef]
  35. Markow, T.A.; Pfeiler, E. Mitochondrial DNA Evidence for Deep Genetic Divergences in Allopatric Populations of the Rocky Intertidal Isopod Ligia occidentalis from the Eastern Pacific. Mol. Phylogenet Evol. 2010, 56, 468–473. [Google Scholar] [CrossRef] [PubMed]
  36. Khalaji-Pirbalouty, V.; Santamaria, C.A.; Puniamoorthy, J.; Mendoza, J.C.E. Description of a New Species of Ligia Fabricius, 1798 (Crustacea: Isopoda: Ligiidae) from Samoa Based on Morphological and Molecular Data, with Notes on L. vitiensis Dana, 1853. Raffles Bull. Zool. 2025, 73, 276–292. [Google Scholar] [CrossRef]
  37. Fourdrilis, S.; Backeljau, T. Highly Polymorphic Mitochondrial DNA and Deceiving Haplotypic Differentiation: Implications for Assessing Population Genetic Differentiation and Connectivity. BMC Evol. Biol. 2019, 19, 92. [Google Scholar] [CrossRef] [PubMed]
  38. Sabatelli, S.; Ruspantini, P.; Cardoli, P.; Audisio, P. Underestimated Diversity: Cryptic Species and Phylogenetic Relationships in the Subgenus Cobalius (Coleoptera: Hydraenidae) from Marine Rockpools. Mol. Phylogenet Evol. 2021, 163, 107243. [Google Scholar] [CrossRef]
  39. Vecchioni, L.; Arculeo, M.; Cottarelli, V.; Marrone, F. Range-Wide Phylogeography and Taxonomy of the Marine Rock Pools Dweller Tigriopus fulvus (Fischer, 1860) (Copepoda, Harpacticoida). J. Zool. Syst. Evol. Res. 2021, 59, 839–857. [Google Scholar] [CrossRef]
  40. Vecchioni, L.; Marrone, F.; Rodilla, M.; Belda, E.J.; Arculeo, M. An Account on the Taxonomy and Molecular Diversity of a Marine Rock-Pool Dweller, Tigriopus fulvus (Copepoda, Harpacticoida). Cienc. Mar. 2019, 45, 59–75. [Google Scholar] [CrossRef]
  41. Yin, J.; Pan, D.; He, C.; Wang, A.; Yan, J.; Sun, H. Morphological and Molecular Data Confirm Species Assignment and Dispersal of the Genus Ligia (Crustacea: Isopoda: Ligiidae) along Northeastern Coastal China and East Asia. Zool. J. Linn. Soc. 2013, 169, 362–376. [Google Scholar] [CrossRef]
  42. Agius, J.; Miceli, M.; Spatola, D. A Geological Overview of the Maltese Archipelago with Reference to the Area of Sliema. Xjenza Online Sci. J. Malta Chamb. Sci. 2023, 11, 53–69. [Google Scholar] [CrossRef]
  43. Salvi, D.; Schembri, P.J.; Sciberras, A.; Harris, D.J. Evolutionary History of the Maltese Wall Lizard Podarcis filfolensis: Insights on the “Expansion-Contraction” Model of Pleistocene Biogeography. Mol. Ecol. 2014, 23, 1167–1187. [Google Scholar] [CrossRef]
  44. Colomba, M.S.; Gregorini, A.; Cilia, D.P.; Liberto, F.; Reitano, A.; Sparacio, I. Molecular Studies on the Genus Muticaria Lindholm, 1925 (Pulmonata, Clausiliidae) from the Maltese Islands. Biodivers. J. 2019, 10, 517–526. [Google Scholar] [CrossRef]
  45. Reyes-Suarez, N.C.; Cook, M.S.; Gačić, M.; Paduan, J.D.; Drago, A.; Cardin, V. Sea Surface Circulation Structures in the Malta-Sicily Channel from Remote Sensing Data. Water 2019, 11, 1589. [Google Scholar] [CrossRef]
  46. Burgio, E.; Catalisano, A.; Salvo, G.; Zava, B. Primo Ritrovamento Di Vertebrati Fossili Nell’isola di Lampedusa (Sicilia). Il Nat. Sicil. 1997, 21, 229–236. [Google Scholar]
  47. Massa, B. Arthropoda Di Lampedusa, Linosa e Pantelleria (Canale Di Sicilia, Mar Mediterraneo). Il Nat. Sicil. 1995, 19, 1–909. [Google Scholar]
  48. Nicolosi, G.; Pantini, P.; Devincenzo, U.; Guariento, L.A.; Italiano, V.; Zanca, L.; Sarà, M.; Isaia, M. New Data on Spiders (Arachnida, Araneae) from the Islands of the Strait of Sicily (Southern Italy) with Taxonomic Notes on Poecilochroa loricata Kritscher, 1996 (Araneae, Gnaphosidae) and Eight New Records for Europe. Eur. Zool. J. 2024, 91, 1009–1034. [Google Scholar] [CrossRef]
  49. Pasta, S.; Garfi, G.; Silvestre Gristina, A.; Marcenò, C.; Guarino, R.; Sparacio, I.; Muscarella, C.; Giacalone, G.; Badalamenti, E.; La Mantia, T.; et al. L’ultima Spiaggia. Il Declino Degli Ecosistemi Dunali Della Sicilia Negli Ultimi 50 Anni—The Last Beach. The Decline of Sicily’s Dune Ecosystems over the Last 50 Years. In Le Dune Costiere—Valore Ambientale, Paesaggistico Ed Economico Risorsa Da Proteggere e Preservare. Monografie Di Geologia Ambientale; Stragapede, F., Ed.; Direzione generale Educazione, Ricerca e istituti Culturali del Ministero della cultura: Roma, Italy, 2024. [Google Scholar]
  50. Highsmith, R.C. Floating and Algal Rafting as Potential Dispersal Mechanisms in Brooding Invertebrates. Mar. Ecol. Prog. Ser. 1985, 25, 169–179. [Google Scholar] [CrossRef]
  51. Thiel, M.; Gutow, L. The Ecology of Rafting in the Marine Environment. I. the Floating Substrata. Oceanogr. Mar. Biol. Annu. Rev. 2005, 42, 181–264. [Google Scholar] [CrossRef]
  52. Raupach, M.J.; Bininda-Emonds, O.R.P.; Knebelsberger, T.; Laakmann, S.; Pfaender, J.; Leese, F. Phylogeographical Analysis of Ligia oceanica (Crustacea: Isopoda) Reveals Two Deeply Divergent Mitochondrial Lineages. Biol. J. Linn. Soc. 2014, 112, 16–30. [Google Scholar] [CrossRef]
  53. Kim, G.; Kim, H.; Mun, S.; Choi, E.H.; Nguyen, A.D.; Hwang, U.W. Molecular Population Genetics and Phylogeographic Studies of Ligia exotica and Ligia cinerascens in East Asia. Front. Mar. Sci. 2023, 10, 1260171. [Google Scholar] [CrossRef]
  54. Guarino, R.; Pasta, S. Sicily: The Island That Didn’t Know to Be an Archipelago. Berichte Der Reinhold-Tuxen-Ges. 2018, 30, 133–148. [Google Scholar]
Table 1. Sampled localities. The “Locality” column reports the name of the island followed by the toponym of the site (where available). The ISO 3166-1 alpha-3 codes are provided to indicate the corresponding country (i.e., MLT: Malta; ITA: Italy).
Table 1. Sampled localities. The “Locality” column reports the name of the island followed by the toponym of the site (where available). The ISO 3166-1 alpha-3 codes are provided to indicate the corresponding country (i.e., MLT: Malta; ITA: Italy).
CountryLocalityLatitudeLongitudeSampling DateCOI A.N.Clade
MLTMalta, Baħar iċ-Ċagħaq35.949614.446427/09/2024PX239617-PX239618A
MLTMalta, Qawra Point35.959914.425427/09/2024PX239610, PX239619A
MLTMalta, Birżebbuġa35.832514.531528/09/2024PX239620A
MLTComino36.005214.335102/10/2024PX239616, PX239629A
MLTMalta, Ċirkewwa35.986914.343902/10/2024PX239615, PX239628A
MLTGozo, Daħlet Qorrot36.049414.317116/10/2024PX239630A
MLTMalta, Marsaxlokk35.833114.545828/09/2024PX239611, PX239621B
MLTMalta, Wied iż-Żurrieq35.820814.452128/09/2024PX239612, PX239622B
MLTMalta, Xagħra35.884614.554230/09/2024PX239613, PX239623B
MLTMalta, Zonqor35.869214.572730/09/2024PX239624-PX2396245B
ITASicily, Cava D’Aliga36.717414.701513/10/2024PX239635-PX2396356C
MLTMalta, Gnejna35.921614.344101/10/2024PX239614, PX239627D
MLTGozo, Dwejra36.050714.190116/10/2024PX239631-PX2396312D
MLTGozo, Xlendi36.028914.214916/10/2024PX239637D
MLTMalta, Popeye Cliffs35.958314.338318/10/2024PX239633-PX239634D
ITALampedusa, Cala Croce35.501112.593327/05/2025PX239651-PX239652E
ITALampedusa, Punta Sottile35.495112.630727/05/2025PX239649-PX23964950E
ITASicily, San Vito Lo Capo38.179612.733319/09/2011PX239626, PX239644F
ITASicily, Capo D’Orlando38.165514.748202/11/2024PX239640-PX2396401F
ITASicily, Barcarello38.209213.281901/06/2019PX239609F
ITAPantelleria, Punta Bue Marino36.837811.963201/05/2018PX239605-PX2396058H
ITASicily, Torretta Granitola37.566712.660801/11/2024PX239638-PX2396389H
ITAFavignana, Calafumere37.933112.321511/12/2024PX239642-PX239643H
ITASicily, Licata37.101213.883404/02/2025PX239645-PX2396456H
ITAMarettimo, Scugghiazzu37.972112.070011/05/2025PX239653-PX2396534H
ITALinosa, Molo Mannarazza35.874812.864901/06/2025PX239647-PX2396478H
Table 2. Estimates of Evolutionary Divergence (uncorrected p-distance) over sequence pairs within and between groups (haplogroups).
Table 2. Estimates of Evolutionary Divergence (uncorrected p-distance) over sequence pairs within and between groups (haplogroups).
Within GroupsBetween Groups
ABCDEFG
A0.004
B0.0030.161
C0.0000.1700.176
D0.0060.1420.1320.179
E0.0010.1500.1390.1710.090
F0.0410.1350.1270.1770.0890.092
G0.0050.1370.1280.1710.0870.0890.063
H0.0060.1500.1320.1750.0960.1020.0760.055
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Faraone, F.P.; Vecchioni, L.; Sciberras, A.; Di Gangi, A.; Deidun, A. First Insights into the Mitochondrial DNA Diversity of the Italian Sea-Slater Across the Strait of Sicily. Diversity 2025, 17, 622. https://doi.org/10.3390/d17090622

AMA Style

Faraone FP, Vecchioni L, Sciberras A, Di Gangi A, Deidun A. First Insights into the Mitochondrial DNA Diversity of the Italian Sea-Slater Across the Strait of Sicily. Diversity. 2025; 17(9):622. https://doi.org/10.3390/d17090622

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Faraone, Francesco Paolo, Luca Vecchioni, Arnold Sciberras, Antonella Di Gangi, and Alan Deidun. 2025. "First Insights into the Mitochondrial DNA Diversity of the Italian Sea-Slater Across the Strait of Sicily" Diversity 17, no. 9: 622. https://doi.org/10.3390/d17090622

APA Style

Faraone, F. P., Vecchioni, L., Sciberras, A., Di Gangi, A., & Deidun, A. (2025). First Insights into the Mitochondrial DNA Diversity of the Italian Sea-Slater Across the Strait of Sicily. Diversity, 17(9), 622. https://doi.org/10.3390/d17090622

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