A research project has tested the hypothesis that Asian common toad populations across Southeast Asia are genetically similar owing to their commensal nature and high dispersive ability. To the researchers’ surprise, three genetically divergent groups of toads were found, each in a different geographic area (mainland Southeast Asia, coastal Myanmar and the islands of Java and Sumatra).
The ranges of these three groups of toads were also found to have statistically different climates. This suggests that the toads may be adapting to local climatic conditions and evolving into separate species. Thus, toads of one group may not be able to disperse and persist within the range of another group because of climatic differences. More.
Of course, we would only know if they were evolving into separate species, as opposed to just well-adapted local variants, if they could no longer produce fertile offspring together. See, for example, the deflated tale of Darwin’s finches.
But every time one brings up the fact that the concept of speciation is groaning under the weight of sheer meaninglessness, Darwin’s followers write in to remind us that everyone knows that, but so what?
Funny, the old Brit toff called his book On the Origin of Species, but his follower say it doesn’t matter if the concept of species has more holes than a cheese grater.
See also: Rethink evolution for progress in science
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Here’s the abstract:
The Asian common toad (Duttaphrynus melanostictus) is a human commensal species that occupies a wide variety of habitats across tropical Southeast Asia. We test the hypothesis that genetic variation in D. melanostictus is weakly associated with geography owing to natural and human-mediated dispersal facilitated by its commensal nature. Phylogenetic and population genetic analyses of mitochondrial and nuclear DNA sequence variation, and predictive species distribution modelling, unexpectedly recovered three distinct evolutionary lineages that differ genetically and ecologically, corresponding to the Asian mainland, coastal Myanmar and the Sundaic islands. The persistence of these three divergent lineages, despite ample opportunities for recent human-mediated and geological dispersal, suggests that D. melanostictus actually consists of multiple species, each having narrower geographical ranges and ecological niches, and higher conservation value, than is currently recognized. These findings also have implications for the invasion potential of this human commensal elsewhere, such as in its recently introduced ranges on the islands of Borneo, Sulawesi, Seram and Madagascar. (paywall) – Guinevere O. U. Wogan, Bryan L. Stuart, Djoko T. Iskandar, Jimmy A. McGuire. Deep genetic structure and ecological divergence in a widespread human commensal toad. Biology Letters, 2016; 12 (1): 20150807 DOI: 10.1098/rsbl.2015.0807