Based on genetic and morphological evidence, Senczuk et al. (2019) formally raised the Podarcis populations from the Western Pontine Islands, previously classified as several subspecies of P. siculus, to species rank, i.e. Podarcis latastei (Bedriaga, 1879). This taxonomic change was not accepted in the checklist of the European herpetofauna by Speybroeck et al. (2020), recently published on Amphibia-Reptilia. In this note we respond to the reasons given by Speybroeck and colleagues and support the validity of Podarcis latastei as an endemic Italian species

Bohme, W

Castiglia, R

Corti, C

Senczuk, G

English

Archivio della ricerca- Università di Roma La Sapienza

Amphibia-Reptilia 42 (2021): 263-267 brill.com/amreShort NoteIn “defense” of Podarcis latastei, an Italian insular endemic species(Squamata: Lacertidae)Riccardo Castiglia1,2,∗, Gabriele Senczuk3, Wolfgang Böhme4, Claudia Corti5Abstract. Based on genetic and morphological evidence, Senczuk et al. (2019) formally raised the Podarcis populations fromthe Western Pontine Islands, previously classified as several subspecies of P. siculus, to species rank, i.e. Podarcis latastei(Bedriaga, 1879). This taxonomic change was not accepted in the checklist of the European herpetofauna by Speybroeck et al.(2020), recently published on Amphibia-Reptilia. In this note we respond to the reasons given by Speybroeck and colleaguesand support the validity of Podarcis latastei as an endemic Italian species.Keywords: island, Italian wall lizard, Lataste’s lizard, species delimitation, taxonomy.In a recent review Speybroeck et al. (2020)provided an updated annotated species list ofthe European herpetofauna. This list leaves thespecies included in four previous checklists(Gasc et al., 1997, 2004; Sindaco and Jere-cenko, 2008; Sindaco, Venchi and Grieco, 2013)unchanged, testing the validity of all new taxaproposed in the last years. In doing this, a con-servative approach was applied since a series ofrecent taxonomic proposals have been rejected.Following three recent detailed works basedon genetics and morphology (Senczuk et al.,2018a, 2018b, 2019), Senczuk et al. (2019) for-mally raised the Podarcis populations from the1 - Dipartimento di Biologia e Biotecnologie “Charles Dar-win”, Università di Roma La Sapienza, via A. Borelli50, 00161 Roma, Italy2 - Museo di Anatomia Comparata “Battista Grassi”, viaA. Borelli 50, 00161 Roma, Italy3 - Dipartimento di Agricoltura, Ambiente e Alimenti, Uni-versity of Molise, 86100, Campobasso, Italy4 - Zoologisches Forschungsmuseum Alexander Koenig,Adenauerallee 160, 53113 Bonn, Germany5 - Museo di Storia Naturale dell’Università di Firenze,Museo “La Specola”, Via Romana 17, 50125 Firenze,Italy∗Corresponding author;e-mail: riccardo.castiglia@uniroma1.itWestern Pontine Islands, previously classifiedas several subspecies of P. siculus, to speciesrank, i.e., Podarcis latastei (Bedriaga, 1879), as‘latastei’ was the oldest name available. How-ever, Speybroeck et al. (2020) maintained intheir checklist P. latastei as a subspecies of theWestern Pontine Islands within the polytypicspecies P. siculus (Rafinesque, 1810).Three points were given by Speybroeck et al.(2020, p. 21) for this decision:1. “. . . the amount of divergence betweenthe Western Pontine populations and the restof the P. siculus complex in Senczuk et al.(2019) is only presented as a combined mtDNAand nuclear DNA tree, not allowing to checkif nuclear data independently supports thisspecies-level divergence or not”.2. “More detailed results by Senczuk et al.(2017, 2018) display a much more complexsituation, where the Western Pontine lineageappears as one of several deeply divergent lin-eages in P. siculus, and latastei and siculus arenot reciprocally monophyletic”.3. “While Senczuk et al. (2018) indicateddifferentiation in nuclear DNA between at leastsome of the main mtDNA lineages in P. siculus,© Koninklijke Brill NV, Leiden, 2021. DOI:10.1163/15685381-bja10047Downloaded from Brill.com04/21/2021 07:11:39PMvia free access264 R. Castiglia et al.no information on their level of reproductiveisolation is yet available”.Therefore Speybroeck et al. (2020) concludethat: “As a consequence, while the TC (. . . Tax-onomic Committee . . . ) acknowledges that P.siculus as currently understood is possibly madeup of several species, one of them correspond-ing to the Western Pontine islands populations,we consider adopting any formal taxonomicchange premature”.We have different arguments to answer tosuch criticisms, detailed below point by point,and we think that present evidence supports therecognition of the species rank for P. latastei:1. In Senczuk et al. (2019) the results ofmtDNA and nuDNA were presented com-bined in a single tree to corroborate thephylogenetic position of P. latastei. Infact, separate mtDNA and nuDNA analy-sis were already available in Senczuk etal. (2018b). In this last paper, mtDNAphylogeny is presented as a phylogenetictree while, nuDNA relationships as twoseparate statistical parsimony networks(MC1R and B-FIB). These two networksshowed a clear separation of P. latasteiin respect to all other P. siculus popula-tions. A certain level of haplotype sharingis present in the two species that there-fore lack for a complete monophyly atthese two markers. However, this situationis comparable with that observed amongpairs of accepted species in Podarcis as,for example, in the Iberian and NordAfrican group of species (Pinho, Harrisand Ferrand, 2008). In fact, in this groupthere is a complete lack of monophylyat nuclear markers of the mitochondrial-defined groups with many alleles that areeven shared by distinct species (Pinho,Harris and Ferrand, 2008) and this isalso true among very highly differentiatedones (Pinho, Harris and Ferrand, 2008;Salvi, Pinho and Harris, 2017). This sit-uation has been interpreted by the authorsas due to ancestral polymorphism and toinstances of introgression (Pinho et al.,2008).2. Speybroeck et al. (2020) suggested thatthe elevation of P. latastei to species levelwould led to a non-monophyletic condi-tion in P. siculus because in Senczuk etal. (2018b) P. latastei results as sister ofa subclade of P. siculus. To this criticismwe answer that even if the tree topolo-gies in Senczuk et al. (2018b) suggestedparaphyly of P. siculus, the relationshipsbetween P. latastei and the lineages ofP. siculus are uncertain as the confidencevalue of the node supporting the positionof P. latastei is very low (0.65). Whennuclear and mitochondrial genes are com-bined as in Senczuk et al. (2019), thetopology of the phylogeny changes with P.siculus being monophyletic but still withuncertainty given by the low support valueat the nodes (0.70). Finally, the speciesmonophyly is not a necessary requirementfor species status even in the rules givenby Speybroeck et al. (2020, p. 4). As alsopointed out by Speybroeck et al. (2020)‘Podarcis siculus’ is possibly a speciescomplex awaiting a complete revision thatat the end will probably identify a numberof monophyletic clades.3. The last point raised by Speybroeck etal. (2020) is that since there is no infor-mation on reproductive isolation of themainland lineages of P. siculus, then aspecific status of the insular lineage can-not be assessed. This sentence, implic-itly, considers the lineages in the mainlandof the same taxonomic rank as the onepresent on Western Pontine. Probably, butnot explicitly explained by Speybroeck etal. (2020), because some of these lineageshave a divergence time comparable to thatobserved for P. latastei. We disagree withthis line of thinking. Instead, we think thatthe insularity itself of P. latastei is veryimportant in order to affirm its specific sta-tus. In fact, it is widely recognized thatDownloaded from Brill.com04/21/2021 07:11:39PMvia free accessIn “defense” of Podarcis latastei 265islands represent a set of particular con-ditions for which evolution is acceleratedwith a large number of studies focusing onlizards (e.g., Herrel et al., 2008; Raia etal., 2010; Senczuk et al., 2014; de Amorimet al., 2017; Anderson and Poe, 2019;Zhu et al., 2020). The time of isolationof P. latastei, has been estimated around4 million years (Senczuk et al., 2019), inagreement with the genesis and geologi-cal evolution of these islands (Cadoux etal., 2005). This large time span allowedP. latastei to evolve more markedly thanthe mainland lineages of P. siculus. In fact,we observed a greater distinction of thetwo studied nuclear markers compared tothe distinction observed among the lin-eages present on the mainland (Senczuket al., 2018b). Moreover, and more sig-nificantly, the distinction of P. latasteirespect to mainland populations is showedby the recently published geometric mor-phometry work on variation in head shape(Senczuk et al., 2018a). This study, over-looked and not cited by Speybroeck et al.(2020), showed that the populations of theWestern Pontine Islands are significantlydifferent from those of the mainland aswell as those on the eastern PontineIslands. This result enforces the morpho-logical uniqueness of the Western PontineArchipelago respect to other populations.Moreover, our study has also highlightedanother important aspect. The populationsof the Western Pontine morphologicallyoverlap with those once present on theIsland of Santo Stefano (Eastern Pontine).The latter became extinct in historicaltimes, probably due to the invasion of P.siculus currently the only lacertids on theisland. It is therefore not to be excludedthat P. latastei had a wider distribution thatincluded also Eastern Pontine in the past.An additional aspect that we should consideris that not even a single mitochondrial haplo-type belonging to the continental lineages ofP. siculus has been found on the western Pon-tine Archipelago. Since that P. siculus has col-onized in recent times by long distance pas-sive transport several islands of the Mediter-ranean Sea (Silva-Rocha et al., 2014; Santos etal., 2019), including for example the TremitiIslands and the Eastern Pontine (Senczuk et al.,2017), it seems very strange to us that this hasnot happened for the Western Pontine. Althoughthere are signs of sporadic introgression of somenuclear haplotypes (Senczuk et al., 2018b), theabsence of mitochondrial haplotypes indicatessome type of “blocking” of invasive lizardsbelonging to the mainland. This phenomenonmay include “density blocking”, local adapta-tion or competitive exclusions (Waters et al.,2013) and suggests a certain level of reproduc-tive isolation that would be interesting to studyin depth (Nosil et al., 2005).We understand that the criterium adoptedby Speybroeck et al. (2020) in their checklistis a prudential one that gives value to taxo-nomic stability. However regrettably, there is noguarantee that such approach is more error-freethan the alternative ones (e.g., Robuchon et al.,2019). Artificial taxonomic stability may havenegative consequences for the future of hid-den endemic taxa, as in the case reported hereof P. latastei (Melville et al., 2019), and thismay be particularly dangerous in Europe due toan excessively rigid list of endangered speciesthat govern biodiversity policies in the continent(Gippoliti et al., 2017).Furthermore, we understand all the difficul-ties that Speybroeck et al. (2020) faced in draw-ing up their checklist and the need to findcompromises. However, their decision to onlyconsider recent taxonomic changes while leav-ing the previous species unchanged has nothingto do with “Taxonomy” and even “Biology”.In fact, this procedure risks not considering asvalid species taxa which, on the other hand, aremuch more differentiated than those currentlypresent in the list.For all the above reasons we will continue touse the species rank for the Podarcis populationDownloaded from Brill.com04/21/2021 07:11:39PMvia free access266 R. Castiglia et al.inhabiting the Western Pontine Islands. Thisspecies represents a new undescribed taxon, asalso highlighted by Speybroeck et al. (2020),and it is not a simple elevation of a subspeciesto the rank of species. In fact, only thanksto molecular phylogenetics analyzes emergedthe real evolutionary unit, with its distribu-tion and its evolutionary history hinged on thearchipelago for millions of years.Acknowledgements. We thank Spartaco Gippoliti for hisvaluable comments on the first version of this note andFlavia Annesi for the English revision.ReferencesAnderson, C.G., Poe, S. (2019): Phylogeny, biogeographyand island effect drive differential evolutionary signalsin mainland and island lizard assemblages. Zool. J. Linn.Soc. 185 (2): 301-311.Cadoux, A., Pinti, D.L., Aznar, C., Chiesa, S., Gillot,P.Y. (2005): New chronological and geochemical con-straints on the genesis and geological evolution of Ponzaand Palmarola volcanic islands (Tyrrhenian Sea, Italy).Lithos 81 (1-4): 121-151.de Amorim, M.E., Schoener, T.W., Santoro, G.R.C.C., Lins,A.C.R., Piovia-Scott, J., Brandão, R.A. (2017): Lizardson newly created islands independently and rapidlyadapt in morphology and diet. Proc. Natl Acad. Sci.U.S.A. 114 (33): 8812-8816.Gasc, J.-P., Cabela, A., Crnobrnja-Isailovic, J., Dolmen, D.,Grossenbacher, K., Haffner, P., Lescure, J., Martens, H.,Martínez-Rica, J.P., Maurin, H., Oliveira, M.E., Sofi-anidou, T.S., Veith, M., Zuiderwijk, A. (1997, reprint2004): Atlas of Amphibians and Reptiles in Europe.Societas Europaea Herpetologica and Muséum nationald’Histoire naturelle, Paris.Gippoliti, S., Capula, M., Ficetola, G.F., Salvi, D.,Andreone, F. (2017): Threatened by legislative conser-vationism? The case of the critically endangered Aeolianlizard. Front. Ecol. Evolution 5: 130.Herrel, A., Huyghe, K., Vanhooydonck, B., Backeljau,T., Breugelmans, K., Grbac, I., Van Damme, R.,Irschick, D.J. (2008): Rapid large-scale evolutionarydivergence in morphology and performance associatedwith exploitation of a different dietary resource. Proc.Natl Acad. Sci. U.S.A. 105 (12): 4792-4795.Melville, J., Chaplin, K., Hutchinson, M., Sumner, J., Gru-ber, B., MacDonald, A.J., Sarre, S.D. (2019): Taxon-omy and conservation of grassland earless dragons: newspecies and an assessment of the first possible extinctionof a reptile on mainland Australia. R. Soc. Open Sci. 6:190233.Nosil, P., Vines, T.H., Funk, D.J. (2005): Reproductiveisolation caused by natural selection against immigrantsfrom divergent habitats. Evolution 59 (4): 705-719.Pinho, C., Harris, D.J., Ferrand, N. (2008): Non-equilibriumestimates of gene flow inferred from nuclear genealo-gies suggest that Iberian and North African wall lizards(Podarcis spp.) are an assemblage of incipient species.BMC Evol. Biol. 8 (1): 63.Raia, P., Guarino, F.M., Turano, M., Polese, G., Rippa, D.,Carotenuto, F., Monti, D.M., Cardi, M., Fulgione, D.(2010): The blue lizard spandrel and the island syn-drome. BMC Evol. Biol. 10 (1): 289.Robuchon, M., Faith, D.P., Julliard, R., Leroy, B., Pellens,R., Robert, A., Thévenin, C., Veron, S., Pavoine, S.(2019): Species splitting increases estimates of evolu-tionary history at risk. Biol. Conserv. 235: 27-35.Salvi, D., Pinho, C., Harris, D.J. (2017): Digging up theroots of an insular hotspot of genetic diversity: decou-pled mito-nuclear histories in the evolution of theCorsican-Sardinian endemic lizard Podarcis tiliguerta.BMC Evol. Biol. 17: 63.Santos, J.L., Žagar, A., Drašler, K., Rato, C., Ayres, C., Har-ris, D.J., Carretero, M.A., Salvi, D. (2019): Phylogeo-graphic evidence for multiple long-distance introduc-tions of the common wall lizard associated with humantrade and transport. Amphibia-Reptilia 40: 121-127.Senczuk, G., Castiglia, R., Böhme, W., Corti, C. (2019):Podarcis siculus latastei (Bedriaga, 1879) of the WesternPontine Islands (Italy) raised to the species rank, anda brief taxonomic overview of Podarcis lizards. ActaHerpetol. 14: 71-80.Senczuk, G., Colangelo, P., Avramo, V., Castiglia, R.,Böhme, W., Corti, C. (2018a): A study in scarlet: incipi-ent speciation, phenotypic differentiation and conserva-tion implications of the Podarcis lizards of the westernPontine Islands, Italy. Biol. J. Linn. Soc. 125 (1): 50-60.Senczuk, G., Colangelo, P., De Simone, E., Aloise, G.,Castiglia, R. (2017): A combination of long term frag-mentation and glacial persistence drove the evolutionaryhistory of the Italian wall lizard Podarcis siculus. BMCEvol. Biol. 17: 6.Senczuk, G., García, A., Colangelo, P., Annesi, F., Cas-tiglia, R. (2014): Morphometric and genetic divergencein island and mainland populations of Anolis nebulo-sus (Squamata: Polychrotidae) from Jalisco (Mexico):an instance of insular gigantism. Ital. J. Zool. 81 (2):204-214.Senczuk, G., Havenstein, K., Milana, V., Ripa, C.,De Simone, E., Tiedemann, R., Castiglia, R. (2018b):Spotlight on islands: on the origin and diversificationof an ancient lineage of the Italian wall lizard Podar-cis siculus in the western Pontine Islands. Sci. Rep. 8:15111.Silva-Rocha, I., Salvi, D., Harris, D.J., Freitas, S., Davis,C., Foster, J., Deichsel, G., Adamopoulou, C., Carretero,M.A. (2014): Molecular assessment of Podarcis siculapopulations in Britain, Greece and Turkey reinforcesa multiple-origin invasion pattern in this species. ActaHerpetol. 9 (2): 253-258.Downloaded from Brill.com04/21/2021 07:11:39PMvia free accessIn “defense” of Podarcis latastei 267Sindaco, R., Jeremčenko, V.K. (2008): The Reptiles of theWestern Palearctic. 1. Annotated Checklist and Distribu-tional Atlas of the Turtles, Crocodiles, Amphisbaeniansand Lizards of Europe, North Africa, Middle East andCentral Asia. Monografie Della Societas HerpetologicaItalica. Edizioni Belvedere, Latina.Sindaco, R., Venchi, A., Grieco, C. (2013): The Reptilesof the Western Palearctic 2. Annotated Checklist andDistributional Atlas of the Snakes of Europe, NorthAfrica, the Middle East and Central Asia, With anUpdate to the vol. 1. Societas Herpetologica Italica,Latina.Speybroeck, J., Beukema, W., Dufresnes, C., Fritz, U.,Jablonski, D., Lymberakis, P., Martínez-Solano, I.,Razzetti, E., Vamberger, M., Vences, M., Vörös, J., Cro-chet, P.A. (2020): Species list of the European herpeto-fauna – 2020 update by the Taxonomic Committee of theSocietas Europaea Herpetologica. Amphibia-Reptilia 41(2): 139-189.Waters, J.M., Fraser, C.I., Hewitt, G.M. (2013): Foundertakes all: density-dependent processes structure biodi-versity. Trends Ecol. Evol. 28: 78-85.Zhu, X.M., Du, Y., Qu, Y.F., Li, H., Gao, J.F., Lin, C.X., Ji,X., Lin, L.H. (2020): The geographical diversificationin varanid lizards: the role of mainland versus island indriving species evolution. Current Zool. 66 (2): 165-171.Submitted: October 21, 2020. Final revision received:January 12, 2021. Accepted: January 31, 2021.Associate Editor: Miguel Angel Carretero.Downloaded from Brill.com04/21/2021 07:11:39PMvia free access

In "defense" of Podarcis latastei, an Italian insular endemic species (Squamata: Lacertidae)

https://iris.uniroma1.it/bitstream/11573/1540346/1/Castiglia_Defense_2021.pdf

In "defense" of Podarcis latastei, an Italian insular endemic species (Squamata: Lacertidae)

Abstract

Similar works

Full text

Available Versions

Archivio della ricerca- Università di Roma La Sapienza