Distribution of living Cupressaceae reflects the breakup of Pangea

Abstract

Most extant genus-level radiations in gymnosperms are of Oligocene age or younger, reflecting widespread extinction during climate cooling at the Oligocene/Miocene boundary [∼23 million years ago (Ma)]. Recent biogeographic studies have revealed many instances of long-distance dispersal in gymnosperms as well as in angiosperms. Acting together, extinction and long-distance dispersal are likely to erase historical biogeographic signals. Notwithstanding this problem, we show that phylogenetic relationships in the gymnosperm family Cupressaceae (162 species, 32 genera) exhibit patterns expected from the Jurassic/Cretaceous breakup of Pangea. A phylogeny was generated for 122 representatives covering all genera, using up to 10,000 nucleotides of plastid, mitochondrial, and nuclear sequence per species. Relying on 16 fossil calibration points and three molecular dating methods, we show that Cupressaceae originated during the Triassic, when Pangea was intact. Vicariance between the two subfamilies, the Laurasian Cupressoideae and the Gondwanan Callitroideae, occurred around 153 Ma (124-183 Ma), when Gondwana and Laurasia were separating. Three further intercontinental disjunctions involving the Northern and Southern Hemisphere are coincidental with or immediately followed the breakup of Pangea.ancestral areas reconstruction | molecular clock

Hemisphere-scale differences in conifer evolutionary dynamics

“…Our estimated divergence ages generally agree with results from published studies focusing on Podocarpaceae (15) and Pinaceae (23; in the conservative version of their calibrations), although they are considerably younger than a recently published study of Cupressaceae (24). The discrepancy in age estimates most likely results from differences in the implementation of prior age distributions, because both studies used a similar set of fossils as minimum age constraints.…”

“…The discrepancy in age estimates most likely results from differences in the implementation of prior age distributions, because both studies used a similar set of fossils as minimum age constraints. Mao et al (24) generally used extremely wide uniform priors on age distributions associated with each fossil, potentially biasing posterior densities toward older divergence ages (25). Our conservative use of fossils as stem taxa with narrower lognormal prior age distributions potentially may bias estimates toward younger ages, but the marked relative differences between Northern and Southern Hemisphere clades that are the primary focus of this study remain unaffected.…”

Conceptual and empirical advances in Neotropical biodiversity research

“…Because of the effects of extinction, the pattern of geographic 630 distribution we observe today may be a poor representation of the actual biogeographic history, especially 631 if extinction rates have been unequal among areas (Meseguer et al, 2015) and taxa (Silvestro et al,632 2016). One way to solve this is to include extinct lineages in biogeographic analyses (Mao et al, 2012), 633 or to use their distribution (the fossil record) to constrain inferences of ancestral ranges (Meseguer et al, 2015). This has in many cases revealed a new, different biogeographic history for the study group (Mao et and are the focus of active research programs (see Fine & Bruna, 2016).…”

Anatomía comparada de la madera de Cupressaceae y su correspondencia con los estudios de filogenia

“…El estudio de su distribución ha permitido establecer teorías sobre las migraciones, los centros de dispersión, el origen, las extinciones y la deriva continental. Entre las familias de coníferas destaca Cupressaceae, representada en todos los continentes salvo en la Antártida, y cuyo origen se ubica durante la era del Triásico (Mao et al 2012), cuando Pangea estaba todavía intacta. Se cree que su origen puede establecerse en Asia (Mao et al 2012).…”

“…Entre las familias de coníferas destaca Cupressaceae, representada en todos los continentes salvo en la Antártida, y cuyo origen se ubica durante la era del Triásico (Mao et al 2012), cuando Pangea estaba todavía intacta. Se cree que su origen puede establecerse en Asia (Mao et al 2012). La naturaleza relicta de algunos de sus géneros es de especial importancia en el estudio biogeográfico, permitiendo identificar áreas de endemismo, probablemente causadas por un cambio en las condiciones climáticas (Contreras-Medina y Vega 2002).…”