almost fractally (Zachos,2016

extant sp

Figure 4.

The possibility that most substantial recent lineages aremarked by multi-trait evolutionary bursts is the best hopewe see for a natural species rank.

indefinitely distant future

It may not have the sharply defined multidi-mensional boundaries and stable persistence of a chair, anorganism, or a river, but it is at least as real as a cloud, acity, or a school of fish.

Their isolationis complete and enduring,

isolation

Even if one’s goal is not a resolvedspecies tree, but only the inference of the distribution ofgene trees (Hahn & Nakhleh, 2016), a model of inter-locuscohesion contributes important power to the resu

A cluster, as a simple empirical observa-tion from a set of observed traits (phenotypic or genotypic),cannot predict that its members are similar in any othertraits or loci without a biological model to constrain theoutliers in unstudied dimensions.

Any general-purpose species concept must be based onmore than genealogy or traits

the second as commu-nities reproductively isolated at this moment and possiblyprojected to retain integrity into the future