PT  - JOURNAL ARTICLE
AU  - Carlos Daniel Cadena
AU  - Laura N. Céspedes
TI  - Origin of elevational replacements in a clade of nearly flightless birds – most diversity in tropical mountains accumulates via secondary contact following allopatric speciation
AID  - 10.1101/606558
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 606558
4099  - http://biorxiv.org/content/early/2019/04/12/606558.short
4100  - http://biorxiv.org/content/early/2019/04/12/606558.full
AB  - Tropical mountains are biodiversity hotspots. In particular, mountains in the Neotropics exhibit remarkable beta diversity reflecting species turnover along gradients of elevation. Elevational replacements of species are known since early surveys of the tropics, but data on how such replacements arise are scarce, limiting our understanding of mechanisms underlying patterns of diversity. We employed a phylogenetic framework to evaluate hypotheses accounting for the origin of elevational replacements in the genus Scytalopus (Rhinocryptidae), a speciose clade of passerine birds with limited dispersal abilities occurring broadly in the Neotropical montane region. We found that species of Scytalopus have relatively narrow elevational ranges, closely related species resemble each other in elevational distributions, and most species replacing each other along elevational gradients are distantly related to each other. Although we cannot reject the hypothesis that a few elevational replacements may reflect parapatric speciation along mountain slopes, we conclude that speciation in Scytalopus occurs predominantly in allopatry within elevational zones, with most elevational replacements resulting from secondary contact of formerly allopatric species. Our work suggests that accumulation of species diversity in montane environments reflects colonization processes even in dispersal-limited animals.