The distribution of speciation events attributable to allopatric speciation by vicariance or dispersal for Leptodesma (Leiopteria), Schizophoria (Schizophoria), Floweria, and the crustacean suborder Archaeostraca are summarized in Table 1.
Further analyses suggest that the occurrence of cryptic species is attributable to successive speciation.
Because extinction rates during the Frasnian crisis interval do not exceed background rates, the dramatic biodiversity loss is attributable to anomalously low speciation rates not high extinction rates.
An apparent lack of morphological diversity could be attributable to non-adaptive speciation, but morphometric work would be required in order to quantify phenotypic diversity.
The lack of Late Devonian vicariance is diametrically opposed to the pattern observed in other geologic intervals, which suggests the loss of vicariant speciation attributable to species invasions during the Late Devonian was a causal factor in the biodiversity crisis.
This diversity is probably attributable to a combination of cryptic speciation and intraspecific variation.
This was achievable because two other nodes within the Nicotiana tree have been previously dated based on speciation events attributable to the geographical isolation of Nicotiana populations on Pacific Ocean islands with known geological ages [43].
They may rather be attributable to advances in laboratory culture and molecular speciation methods, increasing awareness, increasing environmental exposure, decreasing immunity to mycobacteria and/or aging and increasingly prevalent susceptible populations [ 4, 10, 12, 24].
Fragmentation of the widespread ancestral population and eventual speciation of water rails is thus attributable to this vicariance event.
Fragmentation of the widespread ancestral population and eventual speciation of water rails is likely attributable to vicariance by a barrier formed by glacial cycles, continuous uplift of the Tibetan Plateau and increased sedimentation in deserts in southern Asia that originated in the Miocene.
