 It is noteworthy that neither Maynard Smith nor Szathmáry are paleontologists, and so there may be a bit of a disconnect between their original proposal and the way that many paleontologists have come to think about major transitions. Several of the transitions from the original list must have occurred way back in the deep past; the fossil record is not likely to give us much insight into the origin of eukaryotes, for instance. Molecular tools may be able to shed some light on macroevolutionary queries about the deep past, however (O’Malley 2016). And paleontologists sometimes take a much broader (and looser) view of major transitions, such that any major evolutionary novelty would count as a major transition. For instance, the evolution of placentation in mammals, or the evolution of feathers in archosaurs, might count as major transitions on this broader view. Currie (forthcoming) draws a distinction between theory-driven approaches to major transitions and phenomena-driven approaches. Paleontologists tend to fall in the latter camp, since they usually begin by thinking about major morphological or phenotypic changes that show up in the fossil record.