The spectacled tetraka , Xanthomixis zosterops , is a small , yellowed - fleeceable songster from Madagascar , and it may stand for a uncommon instance where multiple species fuse back into one . The work , published inEcology and Evolution , suggests that this tropical warbler had undergone speciation in reverse , or despeciation .
The merger of antecedently isolated craniate line of descent is thought to occur under sure circumstance , such as human modification of habitat . Preliminary sequencing of mitochondrial DNA ( mtDNA ) from these Malagasy songbird has suggest a potential instance of blend lineage . So , a team led by Nicholas Block fromStonehill Collegeanalyzed DNA from the muscles and plume of 117 spectacled tetrakas .
Their mtDNA vary up to 7.6 % from one bird to the next , and that ’s a huge amount for animals within the same species . Compare that to human mtDNA from anywhere on the major planet , which varies by 1.5 % at the most . This suggest that tetrakas in the same species had different ancestor . Their atomic DNA , on the other hand , is passing similar – which means that despite their varied evolutionary history , the separate metal money came back together .
“ This is something that wad of people would have allege could n’t happen , ” written report co - authorJohn Batesfrom the Field Museum said in astatement . “ It ’s a very unusual practice of phylogenesis , but this discovery illustrates that strange thing do happen . ” The team found that the spectacled tetraka make up four mtDNA clade that likely commence diverging 3.6 million years ago .
moreover , the researchers examined the DNA of lice living on 18 of these shuttlecock . Ectoparasites like these typically evolve along with their emcee , so each bird species has its own distinct parasite . turn out , spectacled tetrakas living in different part of the island hosted different kinds of sucking louse . That suggests dissimilar leech coinage evolved back when the bird lineages were disjoined – though the biting louse uphold that separation even after the birds unite together .
During blind drunk periods in Madagascar , forests can become linked ; when it ’s ironical , forests become patchy and isolated . The team thinks that tetrakas ancestors became separate mintage when the climate was dry , and then came back together when the forests connect up again . In that case , the parent species likely became nonextant .
[ ViaField Museum ]
