Publications by authors named "Marco A MEndez"
Article Synopsis
- The study aims to clarify the evolutionary relationships of the Orestias genus, previously misclassified under the family Cyprinodontidae due to incomplete data, by using complete genome sequencing.* -
- Researchers sequenced genomes from three Orestias species and created a comprehensive phylogenetic tree, revealing that Orestias is closely related to South American fish rather than distant genera.* -
- Findings indicate that Orestias should be reassigned to its own lineage, closely linked to the Fluviphylacidae family, rather than being grouped with Cyprinodontidae.*
Article Synopsis
- The study examines how historical and contemporary climate changes have influenced the genetic structure of Heleobia ascotanensis, a freshwater snail endemic to the Ascotán Saltpan in South America.
- When analyzing mitochondrial sequences, researchers found diverse haplotypes indicating past population expansions during significant wet events in the Pleistocene, while current population structure appears more fragmented due to geographic barriers.
- Morphometric analyses revealed that more isolated populations exhibit significant morphological differences, suggesting that both genetic and physical traits have diverged due to limited gene flow in contemporary times.
Article Synopsis
- Desert aquatic species often have separated populations because of their fragmented environments, but geography and humidity can aid their movement.
- This study examined how the shape of river drainage systems affects the genetic diversity and movement of a specific frog species in the Atacama Desert.
- Findings revealed three genetic clusters based on river basins, indicating that populations within the same drainage have more gene flow between them, suggesting that the river structure and regional humidity impact their genetic relationships.
Article Synopsis
- Telmatobius is the most diverse group of frogs in the Andean highlands, with a complicated taxonomy due to large variations within species.
- The study focuses on T. marmoratus, which has a broad distribution but is not fully understood, aiming to clarify its species complexities using DNA analysis techniques.
- Results indicate the presence of 7 distinct lineages and 6-10 potential new species within the marmoratus complex, revealing a complex evolutionary history related to ancient water connections in the region.
Article Synopsis
- Orestias ascotanensis is a unique pupfish species found in high-altitude springs in Chile, which offers insights into how organisms adapt to extreme environments.
- Researchers sequenced the genome of this fish and found a contraction in genes related to signaling, while genes involved in microtubule movement and protein regulation expanded.
- The study identified 818 genes under positive selection, particularly those linked to DNA repair, highlighting potential mechanisms this fish uses to survive increased UV radiation at high altitudes.
Article Synopsis
- The study examines the body size variation in the semi-desert toad Rhinella atacamensis, which spans 750 km from the Atacama Desert to central Chile, focusing on how environmental factors influence size differences.
- Researchers measured the snout-vent length of 315 toads from various locations and tested eight ecogeographic hypotheses related to body size.
- Findings indicate that toad size decreases in more arid regions, which contradicts typical expectations; the results support the converse water availability hypothesis, suggesting that foraging behavior influenced by precipitation affects body size in this species.
Article Synopsis
- - Morphometrics was applied to analyze Triatomines, an insect known for its morphological variability, to study how environmental and nutritional factors affect their shape and size in different regions of Bolivia.
- - The research focused on measuring differences in the wings and heads of Triatomines collected from various habitats, revealing significant sexual dimorphism and the influence of diet on head shape.
- - Findings indicate that geometric morphometric techniques can help understand how these insects adapt to their environments, contributing to better strategies for managing their populations and controlling disease transmission.
The morphological variations of four populations of geographically isolated located in the area of inter-Andean valleys and Chaco of Chuquisaca, Bolivia, were evaluated. Fifty-three females and sixty-one males were collected in the peri-domicile and analyzed with geometric morphometrics tools to study the patterns of the head and wing shape variation. The principal component analysis and canonical variate analysis revealed morphological variations between the populations studied, which were then confirmed by the permutation test of the differences between populations using Mahalanobis and Procustes distances.
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- * Researchers studied the effects of exogenous melatonin on two sweet cherry cultivars (Santina and Royal Rainier) during cold storage, finding it helped slow weight loss and improved overall fruit quality.
- * Melatonin increased anthocyanin levels, changed skin color, and enhanced antioxidant metabolism, showing its potential to improve sweet cherry storability by influencing metabolic processes and gene expression.
Article Synopsis
- The study analyzes how body size and forelimb size in non-avian theropods evolved, noting a general trend where larger species have relatively shorter forelimbs, known as negative forelimb allometry, while some groups showed different patterns closer to isometry.
- By applying phylogenetic statistical testing, the research confirms the negative allometry trend but identifies exceptions among specific theropod subclades like Coelophysoidea, which may have lost this ancestral trait.
- The authors discuss the potential link between allometric trends and growth patterns in non-avian theropods, suggesting that some juvenile traits, like longer forelimbs, may have persisted into adulthood in evolving birds
Article Synopsis
- - The identification of minute freshwater snails in Chile is challenging due to similarities in shell morphology, which is complicated by the presence of invasive species like Potamopyrgus antipodarum sharing the habitat with native genera Heleobia and Potamolithus.
- - Through a combined molecular phylogenetic analysis and examination of reproductive and morphological traits, researchers identified various snail species across 51 locations, revealing 10 sites with the invasive mudsnail, 23 with Heleobia, and 7 with Potamolithus.
- - The study highlights significant findings regarding the spread of the invasive mudsnail, suggesting potential species replacement and extinction of native snails, emphasizing the importance of integrative taxonomy for addressing complex species identification in ongoing invas
Article Synopsis
- Telmatobius halli, the first endemic species from Chile described in 1938, has only the original specimens with no additional finds despite many expeditions.
- A review of the expedition by F. G. Hall suggests that the species may actually originate from a location near Collahuasi, not Ollagüe as previously thought.
- Morphological and phylogenetic analyses confirm that T. halli is part of a distinct monophyletic group, leading to the recommendation to redefine its type locality to the Copaquire ravine area in the high Andes of the Tarapacá region.
Article Synopsis
- - The study investigates the genetic diversity, evolutionary history, and physical differences of a freshwater snail species found only in the Ascotán saltpan of Chile, highlighting its distribution across twelve isolated springs affected by past climate changes.
- - Genetic analysis of 322 specimens revealed three distinct genetic populations with varying levels of historical gene flow and some early stages of physical differentiation due to isolation.
- - The findings indicate that these populations have experienced unique demographic histories influenced by environmental fluctuations, suggesting that both current and past events have played a role in their microevolutionary changes, though more research is needed for detailed predictions on genetic variation.
Article Synopsis
- The genus Telmatobius is a diverse group of amphibians found in high-altitude Andean areas, with several species in Chile being endangered or critically endangered.
- Researchers identified and analyzed 44 microsatellite markers from 80 individuals across 8 species, successfully obtaining 22 functional markers for Telmatobius chusmisensis.
- These microsatellite markers are essential for future genetic studies, helping in understanding population dynamics and aiding conservation efforts for the endangered Telmatobius species.
Article Synopsis
- The origin of cryptic species in the genus Callyntra is linked to recent speciation events and environmental factors, with challenges in defining their taxonomy necessitating phylogenetic studies.
- Researchers used mitochondrial and nuclear genes to reconstruct the phylogeny and identify species, uncovering five clades along with indications of five potential new species.
- Findings suggest that specific elytral designs are adapted to different habitats, pointing to parallel evolution and later stabilization as key processes in the development of these cryptic species in central Chile.
Article Synopsis
- Valenciennes, 1839 is a genus of freshwater fish found in the South American Altiplano, with this study focusing on the cytogenetic characteristics of a specific endemic species from Chile.
- The research employed both classical and molecular methods to analyze the distribution of repetitive DNA sequences and constitutive heterochromatin, revealing that the diploid number of chromosomes is 48.
- Findings highlighted significant features such as the location of nucleolar organizing regions (NORs) and the presence of specific DNA sequences, contributing to insights into the chromosomal evolution and conservation status of these fish.
Article Synopsis
- The study assessed the taxonomic identities of two species of Andean frogs, Telmatobius pefauri and T. zapahuirensis, using molecular and morphological data.
- It found that T. pefauri is distributed not just at its known type locality, Murmuntani, but also in several other locations in the region.
- The findings concluded that T. pefauri and T. zapahuirensis are actually the same species, making the latter a junior synonym of the former.
Article Synopsis
- The study focuses on the anuran Rhinella spinulosa, specifically a population living in geothermal streams along the Andes, and examines how this stable environment may lead to local adaptation in life history traits.
- Researchers conducted transcriptome analyses on different developmental stages of the frogs, revealing 194,469 high-quality SNPs and identifying 1,507 genes under positive selection related to the geothermal habitat.
- Findings indicate that the geothermal population exhibits lower transcriptional plasticity and genetic variation compared to frogs from areas with fluctuating temperatures, enhancing the understanding of molecular mechanisms behind adaptation in these environments.*
Article Synopsis
- The article DOI: 10.1371/journal.pone.0170380 has been updated to correct previous inaccuracies.
- The corrections aim to enhance the clarity and reliability of the research findings presented in the original publication.
- Readers are encouraged to refer to the updated version for the most accurate information.
Article Synopsis
- Cochliopidae is a diverse family of aquatic snails primarily found in the New World, with a significant presence in various habitats.
- In Chile, these snails were historically classified under the genus Littoridina but recent studies indicate that most should belong to the genus Heleobia due to anatomical and phylogenetic insights.
- This text reports the formal description of a new species of Heleobia discovered in the Carcote saltpan, based on both genetic and physical characteristics, reinforcing previous findings that indicated its uniqueness through DNA analysis.
Article Synopsis
- * The complete mitochondrial genome was sequenced, revealing a circular DNA structure of 19,312 base pairs with a specific nucleotide composition.
- * Phylogenetic analysis indicates that this frog is closely related to two other species, contributing valuable insights into evolutionary relationships within its genus.
Article Synopsis
- The Andean Altiplano has historically influenced species diversification, particularly in the Telmatobius marmoratus complex, which we studied using genetic variability and migration patterns based on the cytochrome b gene.
- We found four main genetic clades, with significant connections among Telmatobius gigas, T. marmoratus, and T. culeus, indicating complex evolutionary relationships and weaker geographic structure than expected.
- Analysis highlights that protected areas in Chile conserve over half of the phylogenetic diversity (PD) of T. marmoratus, while unprotected populations are also significant for overall diversity, pointing to the impact of recent climatic changes on species connectivity and population dynamics.
Article Synopsis
- - A new species of spiny-chest frog, named Alsodes cantillanensis, has been identified in central Chile using morphological and molecular evidence.
- - The type locality is Quebrada Infiernillo, about 65 km from Santiago, where A. cantillanensis and its closely related species A. nodosus coexist.
- - The habitat of A. cantillanensis, which resides in a threatened Nothofagus macrocarpa forest, highlights the need for further research on its conservation and the broader ecological understanding of spiny-chest frogs in the region.
Article Synopsis
- * This study investigates the genetic diversity of Peltigera terricolous cyanolichens and their cyanobiont Nostoc across three different habitat types in Karukinka Natural Park, classified by their conservation states.
- * Results show that both native forest types have higher lichen diversity and unique species compared to grasslands, suggesting that preserving forest quality is crucial for maintaining terricolous lichen diversity.