Comparative topographic analyses on the foramen magnums of two hystricomorphs: the crested porcupine (Hystrix cristata) and greater cane rat (Thryonomys swinderianus). Implications for typology, phylogeny and evolution in rodents.

We observe that complexities in foramen magnum architecture between these indicates parcellation of shape and size variance and contributes as evidence for structural evolution, systematics, fundamental similarities and differences offers an explanation that both are related through evolutionary proces of descent as baseline data and further support the suggestion; hystricidae in phylogenetic tree are better evolved and separate from thryonomidae.