Günter Gollmann, Walter Hödl and Annemarie Ohler
Miguel Vences, Philip de Pous, Violaine Nicolas, Jesús Díaz-Rodríguez, David Donaire, Karen Hugemann, J. Susanne Hauswaldt, Felix Amat, Juan A.M. Barnestein, Sergé Bogaerts, Abdellah Bouazza, Salvador Carranza, Pedro Galán, Juan Pablo González de la Vega, Ulrich Joger, Aziza Lansari, El Hassan El Mouden, Annemarie Ohler, Delfi Sanuy, Tahar Slimani and Miguel Tejedo
Painted frogs (Discoglossus) contain five to six species of Western Palearctic anurans that are mainly distributed in allopatry. We here provide the first comprehensive assessment of the phylogeography of the Moroccan species D. scovazzi and geographically characterize its contact zone with D. pictus in Eastern Morocco. Discoglossus scovazzi shows, in general, a weak phylogeographic structure across Morocco on the basis of mitochondrial DNA sequences of the cytochrome b gene, with only populations centered in the Atlas Mountains characterized by the presence of slightly divergent haplotypes. In eastern Morocco, all populations east of the Moulouya River were clearly assignable to D. pictus. This species was also found along the Mediterranean coast west of the Moulouya, in the cities of Nador and Melilla, suggesting that not the river itself but the wide arid valley extending along much of the river (except close to the estuary) acts as a possible distributional barrier to these frogs. No sympatry of D. scovazzi with D. pictus was observed, and all specimens were concordantly assigned to either species by DNA sequences of cytochrome b and of the nuclear marker RAG1. Species distribution models of the two taxa show largely overlapping areas of suitable habitat, and the two species’ niches are significantly more similar than would be expected given the underlying environmental differences between the regions in which they occur. Comparative data are also presented from the southern Iberian contact zone of D. galganoi galganoi and D. g. jeanneae. These taxa showed less clear-cut distributional borders, extensively shared RAG1 haplotypes, and had instances of sympatric occurrence on the basis of cytochrome b haplotypes, in agreement with the hypothesis of a yet incomplete speciation. In this wide contact zone area we found mitochondrial sequences containing double peaks in electropherograms, suggesting nuclear pseudogenes or (less likely) heteroplasmy, possibly related to the ongoing admixture among the lineages.
Violaine Nicolas, Violaine Nicolas, Philippe Grandcolas, Violaine Nicolas, Philippe Grandcolas, Frédéric Braux, Violaine Nicolas, Philippe Grandcolas, Frédéric Braux, Hervé Jourdan, Violaine Nicolas, Philippe Grandcolas, Frédéric Braux, Hervé Jourdan, Atoloto Malau, Violaine Nicolas, Philippe Grandcolas, Frédéric Braux, Hervé Jourdan, Atoloto Malau, Arnaud Couloux, Violaine Nicolas, Philippe Grandcolas, Frédéric Braux, Hervé Jourdan, Atoloto Malau, Arnaud Couloux and Annemarie Ohler
New Caledonia is a megadiverse tropical island in the southwest Pacific, however, inhabited by only one species of amphibian, Litoria aurea (Hylidae). We used both molecular (CO1 and ND4 gene sequencing) and morphometric data to explore its geographical origin and timing of colonisation. We tested whether this species arrived through transoceanic dispersal before human arrival in the island, or recently through anthropogenic introduction. We found a weak phylogeographical structure within this species, and lower haplotype diversity in New Zealand, New Caledonia and Wallis compared to Australia. No significant genetic differentiation was found between pairs of populations in New Caledonia and Wallis, or between pairs of population from these two islands. We observed a high level of morphometric differentiation between Australian and island populations, and a low level of morphometric differentiation between island populations. Our results support an Australian origin for insular frogs. The possibility of a trans-marine dispersal from Australia to New Caledonia and/or Wallis in-between the Eocene and the Pleistocene cannot be favoured, given the low level of genetic differentiation. Our results are consistent with a recent human introduction, most likely during European times. Our data support the historical absence of amphibians in the old island New Caledonia, and is consistent with the new biogeographical paradigm that this island was totally re-colonized after emergence in Eocene. More studies are necessary to explain the success of this frog in oceanic islands, where it is widespread and abundant, compared to Australia, where it is declining.
Miguel Vences, Jason L. Brown, Amy Lathrop, Gonçalo M. Rosa, Alison Cameron, Angelica Crottini, Rainer Dolch, Devin Edmonds, Karen L.M. Freeman, Frank Glaw, L. Lee Grismer, Spartak Litvinchuk, Margaret G. Milne, Maya Moore, Jean François Solofo, Jean Noël, Truong Quang Nguyen, Annemarie Ohler, Christian Randrianantoandro, Achille P. Raselimanana, Pauline van Leeuwen, Guinevere O.U. Wogan, Thomas Ziegler, Franco Andreone and Robert W. Murphy
The black-spined toad, Duttaphrynus melanostictus, is widespread in South and South-East (SE) Asia, although recent molecular analyses have revealed that it represents a species complex (here called the D. melanostictus complex). Invasive populations of this toad have been detected in Madagascar since, at least, 2014. We here trace the origin of this introduction based on mitochondrial DNA sequences of 340 samples. All 102 specimens from Madagascar have identical sequences pointing to a single introduction event. Their haplotype corresponds to a lineage occurring in Cambodia, China, Laos, Thailand, Vietnam, and some locations of eastern Myanmar and northern Malaysia, here named the SE Asian lineage. Within this lineage, specimens from one location in Cambodia and three locations in Vietnam have the same haplotype as found in Madagascar. This includes Ho Chi Minh City, which has a major seaport and might have been the source for the introduction. Species distribution models suggest that the current range of the Madagascan invasive population is within the bioclimatic space occupied by the SE Asian lineage in its native range. The potential invasion zone in Madagascar is narrower than suggested by models from localities representing the full range of the D. melanostictus complex. Thus, an accurate taxonomy is essential for such inferences, but it remains uncertain if the toad might be able to spread beyond the potential suitable range because (1) knowledge on species-delimitation of the complex is insufficient, and (2) the native range in SE Asia might be influenced by historical biogeography or competition.