The endemic Hawaiian lobeliads are exceptionally species rich and exhibit striking diversity in habitat, growth form, pollination biology and seed dispersal, but their origins and pattern of diversification remain shrouded in mystery. Up to five independent colonizations have been proposed based on morphological differences among extant taxa. We present a molecular phylogeny showing that the Hawaiian lobeliads are the product of one immigration event; that they are the largest plant clade on any single oceanic island or archipelago; that their ancestor arrived roughly 13 Myr ago; and that this ancestor was most likely woody, wind-dispersed, bird-pollinated, and adapted to open habitats at mid-elevations. Invasion of closed tropical forests is associated with evolution of fleshy fruits. Limited dispersal of such fruits in wet-forest understoreys appears to have accelerated speciation and led to a series of parallel adaptive radiations in Cyanea, with most species restricted to single islands. Consistency of Cyanea diversity across all tall islands except Hawai`i suggests that diversification of Cyanea saturates in less than 1.5 Myr. Lobeliad diversity appears to reflect a hierarchical adaptive radiation in habitat, then elevation and flower-tube length, and provides important insights into the pattern and tempo of diversification in a species-rich clade of tropical plants.
Dating the Tree of Life has now become central to relating patterns of biodiversity to key processes in Earth history such as plate tectonics and climate change. Regions with a Mediterranean climate have long been noted for their exceptional species richness and high endemism. How and when these biota assembled can only be answered with a good understanding of the sequence of divergence times for each of their components. A critical aspect of dating by using molecular sequence divergence is the incorporation of multiple suitable age constraints. Here, we show that only rigorous phylogenetic analysis of fossil taxa can lead to solid calibration and, in turn, stable age estimates, regardless of which of 3 relaxed clock-dating methods is used. We find that Proteaceae, a model plant group for the Mediterranean hotspots of the Southern Hemisphere with a very rich pollen fossil record, diversified under higher rates in the Cape Floristic Region and Southwest Australia than in any other area of their total distribution. Our results highlight key differences between Mediterranean hotspots and indicate that Southwest Australian biota are the most phylogenetically diverse but include numerous lineages with low diversification rates. biodiversity ͉ diversification rates ͉ fossil calibration ͉ molecular dating ͉ Proteaceae
Imagine if we could compute across phenotype data as easily as genomic data; this article calls for efforts to realize this vision and discusses the potential benefits.
We sequenced the trnL and rpl16 introns of the chloroplast DNA from 95 of the ca. 425 species (30 of 37 sections, seven of eight subgenera) of Primula L. in order to reconstruct the phylogenetic history of the group. Among the 24 additional taxa sampled are representatives of all genera that are likely to be embedded in Primula, as well as outgroups from the Maesaceae, Theophrastaceae, and Myrsinaceae. In the strict consensus of the most parsimonious trees, Primula and the genera embedded in it (Dionysia Fenzl., Sredinskya [Stein] Fedorov, Dodecatheon L., and Cortusa L.) are sister to a clade of several genera previously suspected to be embedded in Primula (Hottonia L., Omphalogramma [Franchet] Franch., and Soldanella L.). In recognition of this, two new rankless names are defined for these clades (/Primula and /Soldanella). Close relationships are inferred between Dionysia and Primula subgenus Sphondylia (Duby) Rupr., Sredinskya and Primula subgenus Primula, Dodecatheon and Primula subgenus Auriculastrum Schott, and Cortusa and Primula subgenus Auganthus (Link) Wendelbo. The largest subgenus, Aleuritia (Duby) Wendelbo, is dispersed among three clades that are not each other's closest relatives. Primula sections Muscarioides Balf. f., Soldanelloides Pax, Denticulata Watt, Armerina Lindley, and Aleuritia Duby are resolved as para-or polyphyletic with moderate to strong support. Throughout, we consider the striking morphological and cytological variation seen in Primula within a phylogenetic context, particularly as it relates to the close relationship implied here between Dionysia and Primula subgenus Sphondylia. The homology of involute leaf vernation in Primula is reconsidered in light of its two independent origins, and we come to the conclusion that vernation in subgenus Sphondylia is better characterized as conduplicate.
Summary• Primula ( c . 430 species) and relatives (Primulaceae) are paradigmatic to our understanding of distyly. However, the common co-occurrence of distyly and monomorphy in closely related groups within the family has made the interpretation of its evolution difficult.• Here, we infer a chloroplast DNA (cpDNA) phylogeny for 207 accessions, including 51% of the species and 95% of the sections of Primula with monomorphic populations, using Bayesian methods. With this tree, we infer the distribution of ancestral states on critical nodes using parsimony and likelihood methods.• The inferred cpDNA phylogeny is consistent with prior estimates. The most recent common ancestor (MRCA) of Primula is resolved as distylous using both methods of inference. However, whether the distyly in Primula , Hottonia , and Vitaliana arose once or three independent times is not clear.• We conclude that monomorphism in descendants of the MRCA of Primula is derived from distyly in all cases. Thus, scenarios for the evolution of distyly that rely on the persistence of primitive monomorphy (such as in Primula section Sphondylia ) require re-evaluation.
An important goal of the angiosperm systematics community has been to develop a shared approach to molecular data collection, such that phylogenomic data sets from different focal clades can be combined for meta-studies across the entire group. Although significant progress has been made through efforts such as DNA barcoding, transcriptome sequencing, and whole-plastid sequencing, the community current lacks a cost efficient methodology for collecting nuclear phylogenomic data across all angiosperms. Here, we leverage genomic resources from 43 angiosperm species to develop enrichment probes useful for collecting ~500 loci from non-model taxa across the diversity of angiosperms. By taking an anchored phylogenomics approach, in which probes are designed to represent sequence diversity across the group, we are able to efficiently target loci with sufficient phylogenetic signal to resolve deep, intermediate, and shallow angiosperm relationships. After demonstrating the utility of this resource, we present a method that generates a heat map for each node on a phylogeny that reveals the sensitivity of support for the node across analysis conditions, as well as different locus, site, and taxon schemes. Focusing on the effect of locus and site sampling, we use this approach to statistically evaluate relative support for the alternative relationships among eudicots, monocots, and magnoliids. Although the results from supermatrix and coalescent analyses are largely consistent across the tree, we find support for this deep relationship to be more sensitive to the particular choice of sites and loci when a supermatrix approach as employed. Averaged across analysis approaches and data subsampling schemes, our data support a eudicot-monocot sister relationship, which is supported by a number of recent angiosperm studies.
To examine relationships and test previous sectional delimitations within Fuchsia, this study used parsimony and maximum likelihood analyses with nuclear ITS and chloroplast trnL-F and rpl16 sequence data for 37 taxa representing all sections of Fuchsia and four outgroup taxa. Results support previous sectional delimitations, except for F. verrucosa, which is related to a Central American clade rather than to section Fuchsia and is described here as a new section Verrucosa. The basal relationships within Fuchsia are poorly resolved, suggesting an initial rapid diversification of the genus. Among the species sampled, there is strong support for a single South Pacific lineage, a southern South American/southern Brazilian lineage, a tropical Andean lineage, and one or two Central American and Mexican lineages. There is no clear support for an austral origin of the genus, as previously proposed, which is more consistent with Fuchsia's sister group relationship with the boreal Circaea. An ultrametric molecular clock analysis (all minimal dates) places the split between Fuchsia and Circaea at 41 million years ago (mya), with the diversification of the modern-day lineages of Fuchsia beginning at 31 mya. The South Pacific Fuchsia lineage branches off around 30 mya, consistent with fossil records from Australia and New Zealand. The large Andean section Fuchsia began to diversify around 22 mya, preceded by the divergence of the Caribbean F. triphylla at 25 mya. The Brazilian members of section Quelusia separated from the southern Andean F. magellanica around 13 mya, and the ancestor of the Tahitian F. cyrtandroides split off from the New Zealand species of section Skinnera approximately 8 mya.
Banksia and Dryandra have undergone extensive speciation and adaptive radiation, especially in Australia's isolated Southwest Botanical Province. We derive a phylogeny for these groups based on cpDNA sequences and use it to reconstruct their historical biogeography and evolution of leaf traits thought to be adapted to drought and/or nutrient poverty. Slowly evolving regions (trnL intron, trnL/trnF spacer) are used to resolve large-scale relationships; faster evolving regions (rp116 intron, psbA/trnH and trnT/trnL spacers) are used to resolve relationships among closely related species. Banksia is paraphyletic with respect to Dryandra. The lineage underwent a basal split into two clades (here named /Cryptostomata and /Phanerostomata), and four infrageneric taxa supported by morphological cladistic analyses (series Spicigerae, Abietinae, Tetragonae, and Banksia) are not monophyletic. Dispersal-vicariance analysis resolves a southwestern Australian origin for the lineage, with two later expansions to the east followed by vicariance events. Stomatal crypts arose with the /Cryptostomata, which is characterized by tough, long-lived leaves and common in southwestern Australia. Sequestering of stomata also arose multiple times in /Phanerostomata, which is characterized by softer, short-lived leaves and common in moister coastal areas, via inrolling of the margins of narrow leaves and restricting stomata to shallow pits. The hypothesis that sclerophylly preadapted the plants to xeromorphy is supported in the case of shallow stomatal pits and deep stomatal crypts, but not narrow, needle-like leaves.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.