TY - JOUR
T1 - Rapid lineage accumulation in a non-adaptive radiation
T2 - Phylogenetic analysis of diversification rates in eastern North American woodland salamanders (Plethodontidae: Plethodon)
AU - Kozak, Kenneth H.
AU - Weisrock, David W.
AU - Larson, Allan
PY - 2006/3/7
Y1 - 2006/3/7
N2 - Adaptive radiations have served as model systems for quantifying the build-up of species richness. Few studies have quantified the tempo of diversification in species-rich clades that contain negligible adaptive disparity, making the macroevolutionary consequences of different modes of evolutionary radiation difficult to assess. We use mitochondrial-DNA sequence data and recently developed phylogenetic methodologies to explore the tempo of diversification of eastern North American Plethodon, a species-rich clade of woodland salamanders exhibiting only limited phenotypic disparity. Lineage-through-time analysis reveals a high rate of lineage accumulation, 0.8 species per million years, occurring 11-8 million years ago in the P. glutinosus species group, followed by decreasing rates. This high rate of lineage accumulation is exceptional, comparable to the most rapid of adaptive radiations. In contrast to classic models of adaptive radiation where ecological niche divergence is linked to the origin of species, we propose that phylogenetic niche conservatism contributes to the rapid accumulation of P. glutinosus-group lineages by promoting vicariant isolation and multiplication of species across a spatially and temporally fluctuating environment. These closely related and ecologically similar lineages persist through long-periods of evolutionary time and form strong barriers to the geographic spread of their neighbours, producing a subsequent decline in lineage accumulation. Rapid diversification among lineages exhibiting long-term maintenance of their bioclimatic niche requirements is an under-appreciated phenomenon driving the build-up of species richness.
AB - Adaptive radiations have served as model systems for quantifying the build-up of species richness. Few studies have quantified the tempo of diversification in species-rich clades that contain negligible adaptive disparity, making the macroevolutionary consequences of different modes of evolutionary radiation difficult to assess. We use mitochondrial-DNA sequence data and recently developed phylogenetic methodologies to explore the tempo of diversification of eastern North American Plethodon, a species-rich clade of woodland salamanders exhibiting only limited phenotypic disparity. Lineage-through-time analysis reveals a high rate of lineage accumulation, 0.8 species per million years, occurring 11-8 million years ago in the P. glutinosus species group, followed by decreasing rates. This high rate of lineage accumulation is exceptional, comparable to the most rapid of adaptive radiations. In contrast to classic models of adaptive radiation where ecological niche divergence is linked to the origin of species, we propose that phylogenetic niche conservatism contributes to the rapid accumulation of P. glutinosus-group lineages by promoting vicariant isolation and multiplication of species across a spatially and temporally fluctuating environment. These closely related and ecologically similar lineages persist through long-periods of evolutionary time and form strong barriers to the geographic spread of their neighbours, producing a subsequent decline in lineage accumulation. Rapid diversification among lineages exhibiting long-term maintenance of their bioclimatic niche requirements is an under-appreciated phenomenon driving the build-up of species richness.
KW - Adaptive radiation
KW - Appalachians
KW - Niche conservatism
KW - Phylogeny
KW - Speciation
UR - http://www.scopus.com/inward/record.url?scp=33645758766&partnerID=8YFLogxK
U2 - 10.1098/rspb.2005.3326
DO - 10.1098/rspb.2005.3326
M3 - Article
C2 - 16537124
AN - SCOPUS:33645758766
SN - 0962-8452
VL - 273
SP - 539
EP - 546
JO - Proceedings of the Royal Society B: Biological Sciences
JF - Proceedings of the Royal Society B: Biological Sciences
IS - 1586
ER -