Morphological variability of Podarcis hispanica (Sauria: Lacertidae) in Portugal

Crespo, Eduardo G.; Vicente, Luı́s; Sá-Sousa, Paulo

doi:10.1163/156853802320877627

Cited by 32 publications

(2 citation statements)

References 14 publications

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“…In concordance with emerging morphological evidence [19-21] both types of markers have documented the existence of several highly differentiated population groups, some of which correspond to the currently accepted species ( P. bocagei, P. carbonelli and P. vaucheri ), whereas others constitute different forms within the polytypic and, from a mitochondrial perspective, paraphyletic P. hispanica . Reported genetic distances at the mitochondrial level are higher than traditional species-delimitation thresholds proposed for squamates [22].…”

Section: Introductionsupporting

confidence: 72%

“…It has also been shown that mitochondrial DNA divergence may not be necessarily corroborated by nuclear divergence because of selection acting on mitochondrial DNA [32]. However, there is a remarkable degree of concordance between the units defined based on mitochondrial DNA [12-15] and those observed by morphological analyses [19-21] and multilocus nuclear data [16-18]. It is therefore unlikely that subdivision within Iberian and North African Podarcis is nonexistent.…”

Section: Discussionmentioning

confidence: 99%

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Non-equilibrium estimates of gene flow inferred from nuclear genealogies suggest that Iberian and North African wall lizards (Podarcis spp.) are an assemblage of incipient species

2008

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BackgroundThe study of recently-diverged species offers significant challenges both in the definition of evolutionary entities and in the estimation of gene flow among them. Iberian and North African wall lizards (Podarcis) constitute a cryptic species complex for which previous assessments of mitochondrial DNA (mtDNA) and allozyme variation are concordant in describing the existence of several highly differentiated evolutionary units. However, these studies report important differences suggesting the occurrence of gene flow among forms. Here we study sequence variation in two nuclear introns, β-fibint7 and 6-Pgdint7, to further investigate overall evolutionary dynamics and test hypotheses related to species delimitation within this complex.ResultsBoth nuclear gene genealogies fail to define species as monophyletic. To discriminate between the effects of incomplete lineage sorting and gene flow in setting this pattern, we estimated migration rates among species using both FST-based estimators of gene flow, which assume migration-drift equilibrium, and a coalescent approach based on a model of divergence with gene flow. Equilibrium estimates of gene flow suggest widespread introgression between species, but coalescent estimates describe virtually zero admixture between most (but not all) species pairs. This suggests that although gene flow among forms may have occurred the main cause for species polyphyly is incomplete lineage sorting, implying that most forms have been isolated since their divergence. This observation is therefore in accordance with previous reports of strong differentiation based on mtDNA and allozyme data.ConclusionThese results corroborate most forms of Iberian and North African Podarcis as differentiated, although incipient, species, supporting a gradual view of speciation, according to which species may persist as distinct despite some permeability to genetic exchange and without having clearly definable genetic boundaries. Additionally, this study constitutes a warning against the misuse of equilibrium estimates of migration among recently-diverged groups.

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Section: Introductionsupporting

confidence: 72%

Section: Discussionmentioning

confidence: 99%

Non-equilibrium estimates of gene flow inferred from nuclear genealogies suggest that Iberian and North African wall lizards (Podarcis spp.) are an assemblage of incipient species

2008

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Morphological and Genetical Differentiation of Lizards (Podarcis bocagei and P. hispanica) in the Ria de Arosa Archipelago (Galicia, Spain) resulting from Vicariance and Occasional Dispersal

Arntzen

Sá-Sousa

2007

Biogeography, Time, and Place: Distributions, Barriers, and Islands

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Interpopulational differences in chemical composition and chemosensory recognition of femoral gland secretions of male lizards Podarcis hispanica: implications for sexual isolation in a species complex

Martı́n

López

2006

Chemoecology

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Molecular studies suggest that the Iberian wall lizard, Podarcis hispanica, forms a species complex with several monophyletic types. In Central Spain two of these types are spatially not isolated and may interact. Sex pheromones are important for species recognition and, thus, differences between lizards' types in chemicals used in intraspecific communication could lead to reproductive isolation. Analyses by GC-MS showed that the femoral gland secretions of adult males of different types were different. Males of one type had twelve exclusive compounds, and proportions of some shared compounds differed. This presumably would reflect selection for the persistency and efficiency of chemical signals in different environments; less volatile compounds and with a higher chemical stability being favoured in the type of lizards inhabiting more humid climatic conditions. Differential tongue-flick rates to scents from femoral secretions indicated that males were able to detect and discriminate between males of different types based on chemical cues alone. In contrast, females detected but did not seem able to discriminate between scents of the two types of males. Thus, multiple factors might be simultaneously acting either against or in favor of speciation, leading, on the one hand, to genetic differences between types, but, on the other hand, probably precluding an effective reproductive isolation in areas where both types of lizards may interact.

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Morphological variability of Podarcis hispanica (Sauria: Lacertidae) in Portugal

Cited by 32 publications

References 14 publications

Non-equilibrium estimates of gene flow inferred from nuclear genealogies suggest that Iberian and North African wall lizards (Podarcis spp.) are an assemblage of incipient species

Non-equilibrium estimates of gene flow inferred from nuclear genealogies suggest that Iberian and North African wall lizards (Podarcis spp.) are an assemblage of incipient species

Morphological and Genetical Differentiation of Lizards (Podarcis bocagei and P. hispanica) in the Ria de Arosa Archipelago (Galicia, Spain) resulting from Vicariance and Occasional Dispersal

Interpopulational differences in chemical composition and chemosensory recognition of femoral gland secretions of male lizards Podarcis hispanica: implications for sexual isolation in a species complex

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