Haldane’s rule occupies a special place in biology as one of the few ‘rules’ of speciation, with empirical support from hundreds of species. And yet, its classic purview is restricted taxonomically to ...

Here, we investigated geographical variation in the relative size of organs (i.e., brain, heart, lung, gallbladder, livers, spleen, kidneys, and digestive tract) among 14 populations of Andrew’s toad ...