Species delimitation and systematics of the green pythons (Morelia viridis complex) of melanesia and Australia

Abstract

Molecular data sets and the increasing use of integrative systematics is revealing cryptic diversity in a range of taxa - particularly in remote and poorly sampled landscapes like the island of New Guinea. Green pythons (Morelia viridis complex) are one of the most conspicuous elements of this island's fauna, with large numbers taken from the wild to supply international demand for exotic pets. We test hypotheses about species boundaries in green pythons from across New Guinea and Australia with mitochondrial genomes, 389 nuclear exons, and comprehensive assessment of morphological variation. Strong genetic structuring of green python populations and species delimitation methods confirm the presence of two species, broadly occurring north and south of New Guinea's central mountains. Our data also support three subspecies within the northern species. Subtle but consistent morphological divergence among the putative taxa is concordant with patterns of molecular divergence. Our extensive sampling identifies several zones of hitherto unknown biogeographical significance on the island of New Guinea. We revise the taxonomy of the group, discuss the relevance of our findings in the context of Papuan biogeography and the implications of our systematic changes for the conservation management of these taxa.