Cladistics and insular evolution, an unfortunate marriage? Another tangle in the Deinogalerix analysis of Borrani...

Insular taxa, such as the late Miocene giant erinaceid Deinogalerix and the insular hominin Homo floresiensis, display a surprisingly primitive placement in cladistic analyses of their respective groups. This has led to speculations of early dispersal onto islands, not corroborated by biogeographical evidence. Insular evolution is notorious for vast phenotypic changes in at least part of the island fauna. These changes encompass typical apomorphies, but, as they may also include evolutionary reversals, a parsimony-based tree will inevitably yield a more basic position in cladograms. Therefore, we need to be cautious in drawing hasty conclusions from phylogenetic trees including insular taxa. Scrutiny is required to monitor possible evolutionary reversals and scenarios should be tested against biogeography to test their viability.