My research interest is mainly focused in the study of biodiversity and diversification and evolution of flowering plants at different evolutionary scales. Biodiversity is not evenly distributed , rather it varies greatly across space (e.g. latitudinal gradients, hotspots, etc.) and across the tree of life (e.g. shifts in diversification rates). My colleagues and I perform studies of molecular phylogenetics
and biogeography, phylogeography, cytogenetics, herbarium study,
phylogenetic comparative methods etc. (i) to quantity the biodiversity (how many species there are and how they are delimited and related) and (ii) to disentangle the mechanisms that generate and maintain the observed biodiversity.
I welcome collaborations with researchers at the undergraduate, graduate or post graduate level in ongoing projects or developing new projects. Please email me if you have questions.
SEE THE LAST EPISODE OF PLANTS ARE COOL TOO AND JOIN THE CHANNEL IN YOUTUBE.
Nature in New York City - Plants are Cool, Too! Episode 7
* MAY- 11-2016
NEW ACCEPTED PUBLICATION DESCRIBING A NEW CAREX SPECIES FROM ECUADOR AND PERU.
CAREX ROALSONIANA
ETYMOLOGY:
"Dedicated
to Eric H. Roalson, North American botanist and professor of the
Washington State University, expert in systematics, taxonomy and
evolution of Cyperaceae, who continuously promoted and encouraged to develop the knowledge in Carex".
PEDRO JIMENEZ-MEJIAS
& MARCIAL ESCUDERO. 2016. NOTES ON SOUTH AMERICAN CAREX SECTION SCHIEDEANAE AND DESCRIPTION OF THE NEW SPECIES CAREX ROALSONIANA(CYPERACEAE). PHYTOTAXA, 260, 185-192. LINK.
*SEPTEMBER-24-2015
NEW ACCEPTED PUBLICATION: CAREX HELODES IS BECOMING A MODEL ORGANISM
ABSTRACT:
•Premise of the study: Microsatellite primers were developed for Carex helodes, a western Mediterranean endemic locally distributed in southern Portugal and southwestern Spain, and rare in northern Morocco.
•Methods and Results: 109 nuclear microsatellite markers were developed using a shotgun pyrosequencing method, resulting in 91 polymorphic and 18 monomorphic loci when tested using 19 individuals sampled from 5 populations from Portugal, Spain and Morocco. Loci averaged 3.23 alleles per locus (SD = 1.15). In a single population (Cortelha population, Portugal), the 34 most polymorphic loci showed a mean observed heterozygosity of 0.357 (SD = 0.292) and expected heterozygosity mean of 0.384 (SD = 0.255).
•Conclusions: Next generation sequencing allows us to develop a high number of genetic markers whose levels of polymorphism are adequate to study gene flow among populations. However, when genotyping the individuals within a population, we found low levels of variation.
JUAN MIGUEL ARROYO, MARCIAL ESCUDERO & PEDRO JORDANO. 2016. ISOLATION OF 91 POLYMORPHIC LOCI IN THE WESTERN MEDITERRANEAN ENDEMIC CAREX HELODES (CYPERACEAE). APPLICATIONS IN PLANT SCIENCES, 4, 1500085. LINK.
*JUNE-10-2015
NEW ACCEPTED PUBLICATION: THE PHYLOGENY OF SMUT FUNGI PARASITES MIRRORS THE PHYLOGENY OF THEIR SEDGE HOSTS!
ABSTRACT:
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, 102, 1108-1114. LINK.
*MAY-19-2015
NEW ACCEPTED PUBLICATION: A VERY COMPLETE STUDY OF CAREX SECTION GLAREOSEA. THIS PAPER IS PART OF ENRIQUE MAGUILLA'S DISSERTATION. CONGRATULATIONS MR. MAGUILLA!
ABSTRACT:
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. PHYLOGENY, SYSTEMATICS AND TRAIT EVOLUTION OF CAREX SECTION GLAREOSAE. AMERICAN JOURNAL
OF BOTANY, 102, 1128-1144. LINK.
