plosone-phylo
pone.0062312.g002
Four models of morphological differentiation.If differentiation occurs instantaneously, there are three possible models of how differentiation may evolve at branching events (cladogenesis). From left to right: (a) under cryptic speciation the two daughter lineages are morphologically identical to their ancestor; (b) with budding cladogenesis, a single daughter lineage is undifferentiated from the ancestor while the other daughter is distinguishable as a separate morphotaxon based on systematic characters; (c) bifurcating cladogenesis produces two daughter lineages which are both recognizably different relative to their ancestor. The fourth pattern of differentiation shown here is repeated events of anagenesis, which is differentiation unassociated with branching. Branching is depicted identically across these figures to contrast the morphological patterns alone and does not reflect discontinuity of populations.
pone.0062312.g002
Four models of morphological differentiation.If differentiation occurs instantaneously, there are three possible models of how differentiation may evolve at branching events (cladogenesis). From left to right: (a) under cryptic speciation the two daughter lineages are morphologically identical to their ancestor; (b) with budding cladogenesis, a single daughter lineage is undifferentiated from the ancestor while the other daughter is distinguishable as a separate morphotaxon based on systematic characters; (c) bifurcating cladogenesis produces two daughter lineages which are both recognizably different relative to their ancestor. The fourth pattern of differentiation shown here is repeated events of anagenesis, which is differentiation unassociated with branching. Branching is depicted identically across these figures to contrast the morphological patterns alone and does not reflect discontinuity of populations.