NEW ACCEPTED PUBLICATION: THE PHYLOGENY OF SMUT FUNGI PARASITES MIRRORS THE PHYLOGENY OF THEIR SEDGE HOSTS!
Background. Fahrenholz’s rule states that common ancestors of extant parasites were parasites of the common ancestors of extant hosts. Consequently, parasite phylogeny should mirror host phylogeny. The smut fungi genus Anthracoidea (Anthracoideaceae) is mainly hosted by species of genus Carex (Cyperaceae). Whether or not smut fungi phylogeny mirrors sedge phylogeny is still under debate. Material and methods. The nuclear DNA region LSU (large subunit; 57 accessions) from 31 different Anthracoidea species and ITS, ETS and trnL-F spacer – trnL intron complex from 41 different Carex species were used to infer the phylogenetic history of parasites and their hosts using a maximum likelihood approach. Event-based and distance-based cophylogenetic methods were used to test the hypothesis of whether or not the phylogeny of smut fungi from the genus Anthracoidea matches the phylogeny of the sedge Carex species they host. Results. Cophylogenetic reconstructions taking into account phylogenetic uncertainties based on event-based analyses demonstrated that Anthracoidea phylogeny shows significant topological congruence with the phylogeny of their Carex hosts. A distance-based test was also significant; the phylogenies of Anthracoide and Carex are partially congruent. Conclusions. The phylogenetic congruence of Anthracoidea and Carex is partially based on smut fungi species being preferentially hosted by closely related sedges (host conservatism). In addition, many different events rather than only codivergence are inferred. All of this evidence suggests that host-shift speciation rather than cospeciation seems to explain the cophylogenetic patterns of Anthracoidea and Carex.
MARCIAL ESCUDERO. 2015 IN
PRESS. PHYLOGENETIC CONGRUENCE OF PARASITIC SMUT FUNGI (ANTHRACOIDEA, ANTHRACOIDEACEAE) AND THEIR HOST PLANTS (CAREX, CYPERACEAE): COSPECIATION OR HOST-SHIFT SPECIATION? AMERICAN JOURNAL
OF BOTANY, 000, 000-0000.
NEW ACCEPTED PUBLICATION: A VERY COMPLETE STUDY OF CAREX SECTION GLAREOSEA. THIS PAPER IS PART OF ENRIQUE MAGUILLA'S DISSERTATION. CONGRATULATIONS MR. MAGUILLA!
Premise of the study: The circumboreal Carex section Glareosae comprises 20-25 currently accepted species. High variability in geographic distribution, ecology, cytogenetics and morphology has led to historical problems both in species delimitation and in circumscribing the limits of the section which is one of the major tasks facing caricologist today. Methods: Phylogenetic reconstructions were performed based on ETS, ITS, G3PDH and matK DNA sequences from 204 samples. Concatenation of gene regions in a supermatrix approach to phylogenetic reconstruction was compared to coalescent-based species-tree estimation. Ancestral state reconstructions were performed for eight morphological characters to evaluate for correspondence between phylogeny and traits used in traditional classification within the section. Key results: The results confirm the existence of a core Glareosae comprising 23-25 species. Most species constitute exclusive lineages, and relationships among species are highly resolved with both the supermatrix and coalescent-based species-tree approaches. We use ancestral state reconstruction to investigate sources of homoplasy underlying traditional taxonomy and species circumscription. We find that even species apparently not constituting exclusive lineages are morphologically homogeneous, raising the question of whether paraphyly of species is a phylogenetic artifact in our study or evidence of widespread homoplasy in characters used to define species. Conclusions: This study demonstrates the monophyly of Carex section Glareosae and establishes a phylogenetic framework for the section. Homoplasy makes many of morphological characters difficult to apply for taxon delimitation. This finding of strong concordance between supermatrix and species-tree approaches to phylogenetic reconstructions suggests that even in the face of incongruence among molecular markers, section-level or species-level phylogenies in Carex are tractable.
ENRIQUE MAGUILLA, MARCIAL ESCUDERO, MARCIA J. WATERWAY, ANDREW L. HIPP, & MODESTO LUCEÑO. 2015 IN
PRESS. PHYLOGENY, SYSTEMATICS AND TRAIT EVOLUTION OF CAREX SECTION GLAREOSAE. AMERICAN JOURNAL
OF BOTANY, 000, 000-0000.
NEW ACCEPTED PUBLICATION: ANOTHER EXCELLENT PAPER DISENTANGLING THE BIPOLAR DISJUNCTION OF CAREX MARITIMA. THIS PAPER IS PART OF TAMARA VILLAVERDE'S DISSERTATION. CONGRATULATIONS TAMARA!
Aim To explain the bipolar distribution of Carex maritima, clarifying the direction of the dispersal and timing of dispersal. We also tested between mountain-hopping and direct long-distance dispersal hypotheses as well as the relationship of C. maritima with biotic and abiotic factors that could explain the bipolar distribution. Location Arctic/boreal latitudes of both hemispheres. Methods Molecular and bioclimatic data were obtained for C. maritima and related species from section Foetidae. We sequenced two (rps16 and 5′trnK intron) plastid DNA regions (cpDNA) and the external and internal transcribed spacers (ETS and ITS) of the nuclear ribosomal gene region (nrDNA) and inferred phylogenetic relationships, divergence time estimates and biogeographical patterns using maximum likelihood, statistical parsimony, Bayesian inference and ecological niche modelling. Results Carex maritima populations from the Southern Hemisphere were genetically and ecologically differentiated from their northern counterparts and formed a monophyletic group nested within of a paraphyletic C. maritima. Divergence time analysis estimated a middle–late Pleistocene divergence of the southern lineage (0.23 Ma; 95% highest posterior density HPD: 0.03 – 0.51 Ma). Southern Hemisphere populations are more stenotopic than the Northern Hemisphere ones, which tolerate harsher conditions. Main conclusions Our results pointed to a middle–late Pleistocene migration of C. maritima by long-distance dispersal, either direct or through mountain-hopping, from the Northern Hemisphere to the Southern Hemisphere.
TAMARA VILLAVERDE, MARCIAL ESUCUDERO, MODESTOLUCEÑO & SANTIAGO MARTIN-BRAVO. 2015 IN
PRESS. LONG-DISTANCE DISPERSAL DURING THE MIDDLE LATE PLEISTOCENE EXPLAINS THE BIPOLAR DISJUNCTION OF CAREX MARITIMA (CYPERACEAE). JOURNAL OF BIOGEOGRAPHY , 000, 000-0000.
NEW ACCEPTED PUBLICATION: CAREX IS FROM NOW ON A MONOPHYLETIC GENUS!
(Cyperaceae), with an estimated 2000 species, nearly cosmopolitan
distribution, and broad range of habitats, is one of the largest
angiosperm genera and the largest in the temperate zone. In this paper
we provide argument and evidence for a broader circumscription of Carex
to add all species currently classified in Cymophyllus (monotypic),
Kobresia (ca. 60 spp.), Schoenoxiphium (ca. 15 spp.), and Uncinia (ca.
70 spp.) to those currently classified as Carex. Carex together with
these other genera comprise tribe Cariceae (subfamily Cyperoideae,
Cyperaceae) and form a well-supported monophyletic group in all
molecular phylogenetic studies to date. Carex as defined here in the
broad sense currently comprises at least four clades. Three are strongly
supported (Siderostictae, Core Vignea, andCore Carex) whereas the
Caricoid clade, which includes all the segregate genera, receives only
weak to moderate support. The Caricoid clade is most commonly split into
two clades, one including a monophyletic Schoenoxiphium and two small
clades of Carex s.s. species, and the other comprising Kobresia, Uncinia
and mostly unispicate Carex s.s. species. Morphological variation is
high in all but the Vignea clade, making it extremely difficult to
define consistent synapomorphies for most clades. On the other hand,
Carex s.l. as newly circumscribed here is clearly differentiated from
the sister groups in tribe Scirpeae by the transition from bisexual
flowers with bristle perianth in the sister group to unisexual flowers
without perianth in Carex. The naked female flowers of Carex s.l. are at
least partially enclosed in a flask-shaped prophyll termed a
perigynium. Carex s.s. is not only by far the largest genus in the
group, but also the earliest published name. As a result, only 72 new
combinations and 58 new speciesreplacement names are required to treat
all of tribe Cariceae as a single genus Carex. We present the required
transfers here, with synonymy, and we argue that this broader
monophyletic circumscription of Carex reflects the close evolutionary relationships within the group and serves the goal of nomenclatural stability better than other possible treatments.
CAREX GLOBAL GROUP. 2015 IN
PRESS. MAKING CAREX MONOPHYLETIC: A NEW BROADER CIRCUMSCRIPTION.
BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, 000, 000-0000.
NEW ACCEPTED PUBLICATION ABOUT THE ORIGIN OF THE BIPOLAR DISJUNCTION.
Aim: The bipolar disjunction, a biogeographical pattern defined by taxa with a distribution at very high latitudes in both hemispheres (> 61oN – > 54oS), is only known to occur in about 30 vascular plant species. The aim of this study was to test the four classic hypotheses proposed to explain this exceptional disjunction in the bipolar species Carex arctogena: convergent evolution, vicariance, mountain-hopping and direct long-distance dispersal. Location: Arctic/boreal and temperate latitudes of both hemispheres. Methods: A combination of molecular and bioclimatic data was used to test phylogeographic hypotheses in C. arctogena. Three chloroplast markers (atp sequenced for all species in Carex sections Capituligerae and Longespicatae. Carex rupestris, C. obtusata and Uncinia triquetra were used as outrgroups. Phylogenetic relationships, divergence time estimates and biogeographical patterns were inferred using maximum likelihood, statistical parsimony and Bayesian inference. Results: Carex sections Capituligerae and Longespicatae formed a monophyletic group that diverged during the late Miocene. Two main lineages of C. arctogena were inferred. Southern Hemisphere populations of C. arctogena shared the same haplotype as a widespread circumboreal lineage. Bioclimatic data shows that Southern and Northern Hemisphere populations currently differ in their ecological regimes. Main conclusions: Two of the four hypotheses accounting for bipolar disjunctions may be rejected. Our results suggest that direct long-distance dispersal the bipolar distribution of C. arctogena.
TAMARA VILLAVERDE, MARCIAL ESCUDERO, SANTIAGO MARTÍN-BRAVO, LEO P. BRUEDERLE, MODESTO LUCEÑO & JULIAN STARR. 2015 IN PRESS. DIRECT LONG-DISTANCE DISPERSAL BEST EXPLAINS THE BIPOLAR DISJUNCTION OF CAREX ARTOGENA (CAREX SECT. CAPITULIGERAE, CYPERACEAE). JOURNAL OF BIOGEOGRAPHY, 000, 000-0000.