Molecular systematics of the endemic Leptaxini (Gastropoda: Pulmonata) on the Azores islands

Riel, Patrick Van; Jordaens, Kurt; Houtte, Natalie Van; Martins, António M. de Frias; Verhagen, Ron; Backeljau, Thierry

doi:10.1016/j.ympev.2005.03.019

Cited by 51 publications

(19 citation statements)

References 46 publications

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“…In agreement, the ranking of Pico individuals within a well-defined species, based on both traditional analytical keys, e.g., Flora Europaea (Tutin et al 1972), and specific studies (Cope 1998), undoubtedly leads to T. baccata. However, Pico individuals have never been the object of a deep taxonomical study.…”

Section: Discussionmentioning

confidence: 76%

Taxus baccata in the Azores: a relict form at risk of imminent extinction

et al. 2010

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Taxus baccata L., a Tertiary relict formerly widespread in the Azores Archipelago, was recently classified as ''probably extinct''. This paper documents the persistence of the species in the Azores and provides its first characterization by means of morphometric and genetic analyses. Only five individuals were found, growing on Pico Island. Although the population size is critically small it retains some highly significant characteristics for the assessment of the genetic diversity of the species and its phylogeography. The leaves of the Azorean provenance were smaller than those of all other Taxus baccata described in literature; moreover, they have a higher stomata density and more numerous stomata rows. These features are all ''primitive'', according to suggested morphological evolutionary trends. We assume that sequence analysis of the chloroplast trnS-trnQ intergenic spacer demonstrates that the Azorean population represents a different evolutionary line within Taxus. This suggests a more direct derivation from ancestors than provenances from Mediterranean and European regions. These individuals may be the last survivors of an ancient lineage, preserved in the Azores as part of the Macaronesian flora. Immediate conservation action focusing on site protection and ex situ reproduction strategies is recommended to save this lineage from imminent extinction.

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Section: Discussionmentioning

confidence: 76%

Taxus baccata in the Azores: a relict form at risk of imminent extinction

et al. 2010

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“…Such stochastic events have been suggested among various marine invertebrates in the Canaries and the Azores (e.g. Riel et al, ; Sá‐Pinto et al, ; Xavier et al, ). Within the D. edwardsi complex, the most interesting case of stochasticity is Madeira, whose haplotypes are very close to those of Tenerife, and embedded in the same MOTU (Figure ).…”

Section: Discussionmentioning

confidence: 84%

Deep segregation in the open ocean: Macaronesia as an evolutionary hotspot for low dispersal marine invertebrates

Vieira

Desiderato

Holdich³

et al. 2019

Molecular Ecology

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Diversification and speciation of terrestrial organisms are anticipated in oceanic islands such as Macaronesia, a group of Atlantic islands that have remained unconnected to continental landmasses. Hitherto, the diversification of marine organisms in oceanic islands, especially those with low vagility, has received little direct empirical analysis using molecular markers. Here, we focus on such a case study, through applying a multilocus molecular approach to investigate the diversity and evolution of a group that lacks a planktonic larval stage, the isopod genus Dynamene, in Macaronesia and Northeast Atlantic. Sequences of two mitochondrial (cytochrome c oxidase subunit I and 16S rRNA) and two nuclear (18S rRNA and 28S rRNA) loci were obtained from specimens of Dynamene edwardsi (Lucas, 1849), Dynamene magnitorata Holdich, 1968 and Dynamene bidentata (Adams, 1800) collected along the Northeast Atlantic and Macaronesia. Although no major phylogeographic structure was detected in D. bidentata and D. magnitorata, from five to nine deeply divergent lineages were evident within D. edwardsi. The divergent lineages displayed genetic distances comparable to those found among established species of peracarids. D. edwardsi exhibits a long, rich and complex phylogeographic history in Macaronesia, where the geodynamics of the islands possibly associated with founder effects and subsequent lack of gene flow among populations confounds patterns based on geographic proximity of targeted populations. Our findings collectively suggest a much larger role of oceanic islands in the diversification of marine invertebrates than previously anticipated. The work provides insights into the origins and dynamics of ongoing geographic segregation and associated deep divergence among sister evolutionary lineages in Macaronesia.

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“…Given all of which, the expectation would be that São Miguel is still accumulating diversity. This is indeed confirmed by detailed anatomical and molecular studies within generic clades (Martins, ; Van Riel et al ., ; Jordaens et al ., ). The relationship of age and ontogeny within the Azores in fact demands further comment.…”

Section: Discussionmentioning

confidence: 99%

Snails on oceanic islands: testing the general dynamic model of oceanic island biogeography using linear mixed effect models

Cameron¹,

Triantis²,

Parent

et al. 2012

Journal of Biogeography

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Aim We collate and analyse data for land snail diversity and endemism, as a means of testing the explanatory power of the general dynamic model of oceanic island biogeography (GDM): a theoretical model linking trends in species immigration, speciation and extinction to a generalized island ontogeny. Location Eight oceanic archipelagos: Azores, Canaries, Hawaii, Galápagos, Madeira, Samoa, Society, Tristan da Cunha. Methods Using data obtained from literature sources we examined the power of the GDM through its derivative ATT2 model (i.e. diversity metric = b1 + b2Area + b3Time + b4Time2), in comparison with all the possible simpler models, e.g. including only area or time. The diversity metrics considered were the number of (1) native species, (2) archipelagic endemic species, and (3) single‐island endemic species. Models were evaluated using both log‐transformed and untransformed diversity data by means of linear mixed effect models. For Hawaii and the Canaries, responses of different major taxonomic groups were also analysed separately. Results The ATT2 model was always included within the group of best models and, in many cases, was the single‐best model and was particularly successful in fitting the log‐transformed diversity metrics. In four archipelagos, a hump‐shaped relationship with time (island age) is apparent, while the other four archipelagos show a general increase of species richness with island age. In Hawaii and the Canaries outcomes vary between different taxonomic groups. Main conclusions The GDM is an intentionally simplified representation of environmental and diversity dynamics on oceanic islands, which predicts a simple positive relationship between diversity and island area combined with a humped response to time. We find broad support for the applicability of this model, especially when a full range of island developmental stages is present. However, our results also show that the varied mechanisms of island origins and the differing responses of major taxa should be taken into consideration when interpreting diversity metrics in terms of the GDM. This heterogeneity is reflected in the fact that no single model outperforms all the other models for all datasets analysed.

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Molecular systematics of the endemic Leptaxini (Gastropoda: Pulmonata) on the Azores islands

Cited by 51 publications

References 46 publications

Taxus baccata in the Azores: a relict form at risk of imminent extinction

Taxus baccata in the Azores: a relict form at risk of imminent extinction

Deep segregation in the open ocean: Macaronesia as an evolutionary hotspot for low dispersal marine invertebrates

Snails on oceanic islands: testing the general dynamic model of oceanic island biogeography using linear mixed effect models

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