Marcelo Gehara

Marcelo Gehara
Rutgers, The State University of New Jersey | Rutgers · Newark College of Arts and Sciences

PhD

About

73
Publications
25,339
Reads
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971
Citations
Additional affiliations
January 2020 - present
Rutgers School of Arts and Sciences, Newark, United States
Position
  • Professor (Assistant)
July 2019 - December 2019
American Museum of Natural History
Position
  • PostDoc Position
December 2015 - June 2019
American Museum of Natural History
Position
  • PostDoc Position

Publications

Publications (73)
Article
Full-text available
Many studies propose that Quaternary climatic cycles contracted and /or expanded the ranges of species and biomes. Strong expansion-contraction dynamics of biomes presume concerted demographic changes of associated fauna. The analysis of temporal concordance of demographic changes can be used to test the influence of Quaternary climate on diversifi...
Article
Full-text available
The Atlantic Forest (AF) of Brazil has long been recognized as a biodiversity conservation hotspot. Despite decades of studies the species inventory of this biome continues to increase with the discovery of cryptic diversity and the description of new species. Different diversification mechanisms have been proposed to explain the diversity in the r...
Article
Full-text available
The South American sea lion (Otaria flavescens) is widely distributed along the southern Atlantic and Pacific coasts of South America with a history of significant commercial exploitation. We aimed to evaluate the population genetic structure and the evolutionary history of South American sea lion along its distribution by analyses of mitochondrial...
Article
Parsley frogs (Pelodytes) comprise the only genus in the family Pelodytidae, an ancient anuran lineage that split from their closest relatives over 140 million years ago. Pelodytes is a Palearctic group restricted to Western Eurasia including three extant species: the eastern species P. caucasicus, endemic to the Caucasus area, and two closely rela...
Article
Full-text available
Two main hypotheses have been proposed to explain the diversification of the Caatinga biota. The riverine barrier hypothesis (RBH) claims that the S~ao Francisco River (SFR) is a major biogeographic barrier to gene flow. The Pleistocene climatic fluctuation hypothesis (PCH) states that gene flow, geographic genetic structure and demographic signatu...
Article
A long history of isolation coupled with complex landscapes makes Madagascar ideal for exploring the historical factors that have shaped patterns of population diversity and endemism. Many species‐level studies have suggested Late Quaternary climate change may have influenced population dynamics in the tropics, but unique biomes and individual spec...
Article
Phylogeographic studies primarily focus on the major role of landscape topography in driving lineage diversification. However, populational phylogeographic breaks may also occur as a result of either niche conservatism or divergence, in the absence of geographic barriers to gene flow. Furthermore, these two factors are not mutually exclusive and ca...
Preprint
Full-text available
Large rivers are ubiquitously invoked to explain the distributional limits and speciation of the Amazon Basin's mega-diversity. However, inferences on the spatial and temporal origins of Amazonian species have narrowly focused on evolutionary neutral models, ignoring the potential role of natural selection and intrinsic genomic processes known to p...
Article
Many phylogeographic studies on species with large ranges have found genetic-geographic structure associated with changes in habitat and physical barriers preventing or reducing gene flow. These interactions with geographic space, contemporary and historical climate, and biogeographic barriers have complex effects on contemporary population genetic...
Article
Full-text available
Tropical mountains hold more biodiversity than their temperate counterparts, and this disparity is often associated with the latitudinal climatic gradient. However, distinguishing the impact of latitude versus the background effects of species history and traits is challenging due to the evolutionary distance between tropical and temperate assembla...
Article
Phylogeography investigates historical drivers of the geographic distribution of intraspecific lineages. Special attention has been given to ecological, climatic, and geological processes in the diversification of the Neotropical biota. Several species sampled across the South American diagonal of open formations (DOF), comprising the Caatinga, Cer...
Article
Full-text available
ContextRivers, landscape, and climate can alter patterns of gene flow and consequently, shape intraspecific genetic variation. While rivers are predicted to halt gene flow in terrestrial species, they may facilitate migration for aquatic species. Amphibians are usually seen as water-dependent, yet multiple studies have indicated that rivers exert a...
Article
Species are being lost at an unprecedented rate during the Anthropocene. Progress has been made in clarifying how species traits influence their propensity to go extinct, but the role historical demography plays in species loss or persistence is unclear. In eastern North America, five charismatic landbirds went extinct last century, and the causes...
Article
We evaluated the role of Quaternary climatic fluctuations on the demographic history and population structure of amphibian species endemic to the ‘campo rupestre’ in the Neotropics, evaluating their distributional shifts, demographic changes, and diversification from the end of Pleistocene to present. We chose two anurans endemic to the high-elevat...
Article
Inferring the history of divergence between species in a framework that permits the presence of gene flow has been crucial for characterizing the “gray zone” of speciation, which is the period of time where lineages have diverged but have not yet achieved strict reproductive isolation. However, estimates of both divergence times and rates of gene f...
Article
Aim Phylogeographic studies show how historical and current changes in landscapes shape the geographic distribution of genetic diversity in species of animals and plants. In particular, for the species of the Diagonal of Open Formations (DOF), the compartmentalization of the Central Brazilian Plateau (CBP) during the Tertiary and climatic oscillati...
Article
Full-text available
The Leptodactylus latrans species group currently comprises eight medium-to large-sized frog species with a convoluted taxonomic history, particularly related to the specific limits of the L. latrans complex, and the species pair Leptodactylus chaquensis-Leptodactylus macrosternum. Their homogeneous external morphology and continental geographic di...
Article
Full-text available
The Leptodactylus latrans species group currently comprises eight medium- to large-sized frog species with a convoluted taxonomic history, particularly related to the specific limits of the L. latrans complex, and the species pair Leptodactylus chaquensis– Leptodactylus macrosternum. Their homogeneous external morphology and continental geographic...
Preprint
Full-text available
Understanding population divergence involves testing diversification scenarios and estimating historical parameters, such as divergence time, population size and migration rate. There is, however, an immense space of possible highly parameterized scenarios that are difsficult or impossible to solve analytically. To overcome this problem researchers...
Preprint
Full-text available
Estimating species divergence with gene flow has been crucial for characterizing the gray zone of speciation, which is the period of time where lineages have diverged but have not yet achieved strict reproductive isolation. However, estimates of divergence times and gene flow often ignores spatial information, for example the formation and shape of...
Article
Understanding the variability of acoustic signals is a first important step for the comprehension of the evolutionary processes that led to current diversity. Herein, we evaluate the variability of the advertisement call of the phyllomedusid species from the genera Phyllomedusa and Pithecopus at different levels: intra-individual, intra-population,...
Preprint
Full-text available
Understanding the variability of acoustic signals is a first important step for the comprehension of the evolutionary processes that led to current diversity. Herein, we evaluate the variability of the advertisement call of the phyllomedusid species from the genera Phyllomedusa and Pithecopus at different levels: intra-individual, intra-population,...
Article
Species diversification can be strongly influenced by geomorphological features, such as mountains, valleys and rivers. Rivers can act as hard or soft barriers to gene flow depending on their size, speed of flow, historical dynamics and regional topographical characteristics. The São Francisco River (SFR) is the largest perennial river in the Caati...
Article
Species diversification can be strongly influenced by geomorphological features, such as mountains, valleys and rivers. Rivers can act as hard or soft barriers to gene flow depending on their size, speed of flow, historical dynamics and regional topographical characteristics. The São Francisco River (SFR) is the largest perennial river in the Caati...
Article
Full-text available
Genetic diversity is an important component of biodiversity, providing the means for species to evolve and adapt in changing environments. Although regions that retain high genetic diversity provide ideal targets for conservation due to their evolutionary potential, they have been poorly mapped in the Neotropics. Here, we mapped genetic diversity,...
Article
Full-text available
For many species, climate oscillations drove cycles of population contraction during cool glacial periods followed by expansion during interglacials. Some groups, however, show evidence of uniform and synchronous expansion while others display differences in the timing and extent of demographic change. We compared demographic histories inferred fro...
Article
Full-text available
Genetic structure can be influenced by local adaptation to environmental heterogeneity and biogeographic barriers, resulting in discrete population clusters. Geographic distance among populations, however, can result in continuous clines of genetic divergence that appear as structured populations. Here we evaluate the relevant importance of these t...
Article
We reconstruct the molecular phylogeny of Near Eastern mountain brook newts of the genus Neurergus (family Salamandridae) based on newly determined RADseq data, and compare the outcomes of concatenation-based phylogenetic reconstruction with species-tree inference. Furthermore, we test the current taxonomy of Neurergus (with four species: Neurergus...
Article
Full-text available
Aim To test three different scenarios to account for the geographic distribution of genetic variation in Dermatonotus muelleri, a fossorial frog endemic of the South American diagonal of open formations (DOF) formed by Chaco, Cerrado, and Caatinga biomes: (a) The pan‐DOF hypothesis, where these biomes behave as a single biogeographical unit and DOF...
Article
Full-text available
Aim To assess the effects of historical events on the tempo and mode of diversification of the lizard Polychrus acutirostris along the South American diagonal of open formations (DOF). Location Caatinga and Cerrado biomes in Brazil. Methods We sequenced fragments of one mtDNA and three nuDNA genes of 68 individuals from 33 localities. We used pop...
Article
Most phylogenies are typically represented as purely bifurcating. However, as genomic data has become more common in phylogenetic studies, it is not unusual to find reticulation among terminal lineages or among internal nodes (deep time reticulation; DTR). In these situations, gene flow must have happened in the same or adjacent geographic areas fo...
Article
Full-text available
Spatial patterns of genetic variation can help understand how environmental factors either permit or restrict gene flow and create opportunities for regional adaptations. Organisms from harsh environments such as the Brazilian semiarid Caatinga biome may reveal how severe climate conditions may affect patterns of genetic variation. Herein we combin...
Data
List of individuals that bear each mitochondrial DNA control region haplotype, and the respective GenBank number. Absolute frequency in the sample and geographic distribution of haplotypes for South American sea lion. (DOCX)
Data
List of individuals that bear each mitochondrial DNA cytochrome b haplotype. Absolute frequency in the sample and geographic distribution of haplotypes for South American sea lion. (DOCX)
Data
Extended Bayesian skyline plot showing the effective population size fluctuation of South American sea lions populations throughout time based on the mtDNA control region. Internal dashed lines are median estimates and thin lines and coloured areas are the 95% Central Posterior Density (CPD) intervals. Nef, effective female population size (log sca...
Data
Extended Bayesian skyline plot showing the effective population size fluctuation of South American sea lions populations throughout time based on the mtDNA control region. Internal black dashed lines are median estimates and thin lines are the 95% CPD intervals. Thin green lines are the individual population trajectories. Nef, effective female popu...
Data
Species and access number of sequences downloaded from GenBank used to estimate the Bayesian phylogeny (Fig 3). (DOCX)
Data
Genetic diversity of South American sea lions for each locus per clustered localities and for the species as whole. (A) Number of alleles, (E) = exclusive alleles, (Ho) observed heterozygosity, (He) expected heterozygosity.* Loci that deviated from HW equilibrium after Bonferroni correction. (DOCX)
Data
Plots from STRUCTURE HARVESTER performed with Evanno’s method. (A) Highest value of (ΔK) = 79.20 on K = 2. (B) Mean of estimated Ln probability of data (± sd) averaging ten runs from K = 1 to K = 10. (TIF)
Data
STRUCTURE bar plot from the test for migrants or hybrids between oceans using the sampling locations (in this case the ocean basin) and the USEPOPINFO model. Each bar is one individual and each colour represents the assignment probability of the individual to belong to that genetic cluster. (TIF)
Article
Full-text available
We aim to evaluate the genetic structure of an Atlantic Forest amphibian species, Scinax eurydice, testing the congruence among patterns identified and proposed by the literature for Pleistocene refugia, microrefugia, and geographic barriers to gene flow such as major rivers. Furthermore, we aim to evaluate predictions of such barriers and refugia...
Data
K values curve for K = 1–10 (Ln Pr (X/K)), and value of DK for K = 4. (PDF)
Data
Posterior distribution of migration rate (effective number of gene copies) into each population estimated with a four-population model. (PDF)
Data
Current effective population size posterior distributions in number of individuals for the two-population and four-population models. Transformations were performed using the geometric mean of the mutation rates (7.52 x 10−7). (PDF)
Data
Posterior probability distributions of divergence parameter estimated by IMa2 transformed to million years. (A) Divergence estimates of the six two-population models. Each curve represents the estimated divergence time between two populations. (B) Divergence time estimates resulting from a four-population model. Each curve represents one of the thr...
Data
Ancestral effective population size posterior distributions in number of individuals for the two-population and four-population models. Transformations were performed using the geometric mean of the mutation rates (7.52 x 10−7). (PDF)
Data
Tissue samples of Scinax eurydice used in the account: voucher number, locality, state, coordinates, sequences, haplotype code and locality code of specimens. Abbreviations of Brazilian states: PB, Paraíba; PE, Pernambuco; AL, Alagoas; SE, Sergipe; BA, Bahia; ES, Espírito Santo; MG, Minas Gerais; RJ, Rio de Janeiro; SP, São Paulo. Collection acrony...
Data
Gene fragment, primer, sequence of primer and reference used in this study. (PDF)
Data
K run numbers, replicates, mean of log-likelihood and standard deviation of log-likelihood. (PDF)
Data
Parameters of posterior distributions of population migration rate estimation for two and four population models. * P < 0.05; ** P < 0.01; *** P < 0.001. (PDF)
Data
IMa2 Divergence Times Estimation Results. (PDF)
Data
Posterior distribution of migration rate (effective number of gene copies) into each population estimated with a two-population model. (PDF)
Article
Full-text available
Scincine lizards in Madagascar form an endemic clade of about 60 species exhibiting a variety of ecomorphological adaptations. Several subclades have adapted to burrowing and convergently regressed their limbs and eyes, resulting in a variety of partial and completely limbless morphologies among extant taxa. However, patterns of limb regression in...
Article
Full-text available
Many tropical organisms show large genetic differences among populations, yet the prevalent drivers of the underlying divergence processes are incompletely understood. We explored the effect of several habitat and natural history features (body size, macrohabitat, microhabitat, reproduction site, climatic heterogeneity, and topography) on populatio...
Article
Full-text available
Species distributed across vast continental areas and across major biomes provide unique model systems for studies of biotic diversification, yet also constitute daunting financial, logistic and political challenges for data collection across such regions. The tree frog Dendropsophus minutus (Anura: Hylidae) is a nominal species, continentally dist...
Article
Full-text available
Species distributed across vast continental areas and across major biomes provide unique model systems for studies of biotic diversification, yet also constitute daunting financial, logistic and political challenges for data collection across such regions. The tree frog Dendropsophus minutus (Anura: Hylidae) is a nominal species, continentally dist...
Article
Full-text available
Day geckos of the Phelsuma lineata group are widespread in Madagascar and have been historically split into numerous species and subspecies based almost exclusively on differences in coloration and body size. We apply phylogenetic and phylogeographic methods to examine the biogeography and taxonomy of these lizards, including explicit tests of vari...
Article
The Apennine Peninsula is one of Europe's main glacial refugial areas and harbors a large number of lineages and species. Here, a pattern of higher genetic diversity in the south compared to that of the north is characteristic of most vertebrates; however, most studies that have produced these results have relied only on inferences based on mitocho...
Article
Full-text available
The evolutionary mechanisms causing intraspecific diversity in aposematic color and pattern remain enigmatic. The strawberry poison frog (Oophaga pumilio) has diversified into a broad array of colors that span the visible spectrum. The most divergent phenotypes of O. pumilio are restricted to separate islands in the Bocas del Toro archipelago in we...