Lista patrón de los tiburones, rayas y quimeras (Chondrichthyes, Elasmobranchii, Holocephali) de México

Llista patró dels taurons, rajades i quimeres (Chondrichthyes, Elasmobranchii, Holocephali) de Mèxic Es presenta una relació de les espècies de taurons, rajades  i quimeres (condrictis) que han estat registrades a les aigües territorials de Mèxic, basada en revisions de bases de dades, literatura, examen físic dels espècimens de col·leccions científiques i registres d’exemplars recol·lectats en treballs de camp durant els darrers quatre anys i que no han estat publicats. La relació conté informació de 214 espècies de condrictis que, com a mínim, han estat registrades a les aigües marines i salobroses de Mèxic, pertanyents a 84 gèneres, 40 famílies i 14 ordres. S’hi inclouen vuit espècies de quimeres, 95 de batoïdeus i 111 de taurons. La condrictiofauna mexicana és una de les més riques del món, amb el 17,3% o més de les espècies conegudes. A més a més, s’ hi inclouen 16 espècies que és probable que siguin presents a Mèxic atesos els seus patrons de distribució.Checklist of sharks, rays and chimaeras (Chondrichthyes, Elasmobranchii, Holocephali) from Mexico We present an annotated checklist of the species of sharks, rays and chimaeras (chondrichthyan fishes) occurring in Mexican waters, based on a thorough review of the literature and electronic database searches, examination of museum collection specimens, and unpublished records obtained during fieldwork conducted in the last four years. The checklist contains information of at least 214 species of chondrichthyan fishes that occur in Mexican marine and brackish waters, assigned to 84 genera, 40 families and 14 orders. It includes eight species of chimaeras, 95 batoids and 111 sharks. Condrichthyan fauna in Mexico is one of the richest in the world, with almost 17.3% of the known species. An additional  16 species are included  as their occurrence in Mexican marine waters is probable according to distributional patterns.Se presenta un listado anotado de las especies de tiburones, rayas y quimeras (Condrictios) que han sido registrados en las aguas territoriales de México, basado en revisiones de bases de datos, literatura, examinación física de los especímenes de colecciones científicas y de registros de ejemplares recolectados en campo durante los últimos cuatro años y que no han sido publicados. El listado contiene información de al menos 214 especies de condrictios que se han registrado en las aguas marinas y salobres de México, pertenecientes a 84 géneros, 40 familias y 14 órdenes. Se incluyen ocho especies de quimeras, 95 de batoideos y 111 de tiburones. La condrictiofauna mexicana es una de las más ricas a nivel mundial, con al menos 17.3% de las especies conocidas. Adicionalmente, 16 especies, se incluyen como especies probables que ocurran en México debido a sus patrones de distribución.Palabras clave: Condrictios, Elasmobranquios, Batoideos, Quimeras, México

Modeling the SARS-CoV-2 sublineages XBB and BQ.1 in Mexico, considering multiple vaccinations, booster dose, waning immunity and cross-immunity

In a population with ongoing vaccinations, the trajectory of a pandemic is determined by how the virus spreads in the unvaccinated, vaccinated without boosters, and vaccinated with boosters, which will exhibit distinct transmission dynamics based on different levels of natural and vaccine-induced immunity. We found that enhancing the use of face masks in a partially vaccinated population is associated with a reduction of new infections, hospitalizations, and deaths. We highly recommend the use of a face mask with at least a 50% efficiency, such as improved cloth and surgical face masks, due to its effectivity and cost ratio. Our simulations indicated that there may be two upcoming Omicron waves (in the last months of 2022 and in May 2023). The magnitude of these waves will be 75% and 40% lower than their prior wave. Moreover, the size of these waves is heavily influenced by immunity parameters like waning immunity and cross-immunity protection. Hence, we recommend continuing the use of face masks to decrease transmission because we are not developing sterilizing immunity if we get infected by a prior sublineage, meaning that we can still get infected regardless of the acquired immunity

Morphology and Sequence Data of Mexican Populations of the Ciliate Parasite of Marine Fishes Trichodina rectuncinata (Ciliophora: Trichodinidae)

Trichodina rectuncinata is one of the trichodinids most widely distributed in marine fish. This ciliate species has been recorded in more than 20 host species belonging to 17 fish families worldwide. Previous comparative studies based on morphometric data revealed considerable morphological variation among specimens from different populations of T. rectuncinata. In this study, we conducted a morphometric- molecular analysis of three populations of T. rectuncinata to evaluate potential differences among 18S rRNA sequences, in relation to morphological variations. Smears were obtained from marine fishes in three localities along the Pacific coast of Mexico. Based on the shape of denticles, we found four different morphotypes for T. rectuncinata. This morphological variability does not correspond with the genetic divergence, suggesting that all analyzed populations belong to the same species. Further analyses using more variable markers are necessary to corroborate the findings of our study.Centro de Estudios Parasitológicos y de Vectore

Morphology and Sequence Data of Mexican Populations of the Ciliate Parasite of Marine Fishes Trichodina rectuncinata (Ciliophora: Trichodinidae)

Trichodina rectuncinata is one of the trichodinids most widely distributed in marine fish. This ciliate species has been recorded in more than 20 host species belonging to 17 fish families worldwide. Previous comparative studies based on morphometric data revealed considerable morphological variation among specimens from different populations of T. rectuncinata. In this study, we conducted a morphometric- molecular analysis of three populations of T. rectuncinata to evaluate potential differences among 18S rRNA sequences, in relation to morphological variations. Smears were obtained from marine fishes in three localities along the Pacific coast of Mexico. Based on the shape of denticles, we found four different morphotypes for T. rectuncinata. This morphological variability does not correspond with the genetic divergence, suggesting that all analyzed populations belong to the same species. Further analyses using more variable markers are necessary to corroborate the findings of our study.Fil: Islas Ortega, Alma G.. Universidad Nacional Autónoma de México; MéxicoFil: Aguilar Aguilar, Rogelio. Universidad Nacional Autónoma de México; MéxicoFil: Marcotegui, Paula Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Martorelli, Sergio Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; ArgentinaFil: Hernández Mena, David. Universidad Nacional Autónoma de México; MéxicoFil: Pérez Ponce de León, Gerardo. Universidad Nacional Autónoma de México; Méxic

Morphology and Sequence Data of Mexican Populations of the Ciliate Parasite of Marine Fishes Trichodina rectuncinata (Ciliophora: Trichodinidae)

Trichodina rectuncinata is one of the trichodinids most widely distributed in marine fish. This ciliate species has been recorded in more than 20 host species belonging to 17 fish families worldwide. Previous comparative studies based on morphometric data revealed considerable morphological variation among specimens from different populations of T. rectuncinata. In this study, we conducted a morphometric- molecular analysis of three populations of T. rectuncinata to evaluate potential differences among 18S rRNA sequences, in relation to morphological variations. Smears were obtained from marine fishes in three localities along the Pacific coast of Mexico. Based on the shape of denticles, we found four different morphotypes for T. rectuncinata. This morphological variability does not correspond with the genetic divergence, suggesting that all analyzed populations belong to the same species. Further analyses using more variable markers are necessary to corroborate the findings of our study.Centro de Estudios Parasitológicos y de Vectore

A global review of problematic and pathogenic parasites of farmed tilapia

Over the past 80 years, tilapia have been translocated globally for aquaculture; active production is recorded in >124 countries. Of 7 million tonnes of tilapia produced in aquaculture, 79% is from 79 countries outside the natural range of tilapia. Capture fisheries account for a further 723,627 tonnes of tilapia, and >47% of this is landed from established invasive populations outside Africa. Tilapias host a rich fauna of parasites, many of which have been translocated with their hosts. This review summarises >2500 host–parasite records from 73+ countries and >820 recorded tilapia translocations (provided in the supplementary materials). This work focuses on the notable pathogens that threaten the health of cultured populations of tilapia, providing a description of their pathology and includes species that also have substantial impacts on wild tilapia populations, where relevant. For each major parasite taxonomic group, we highlight which parasites have been translocated or have been acquired from the new environments into which tilapia have been introduced, together with remarks on standard treatment approaches and research on them and their management and control. Regarding the theme ‘Tilapia health: quo vadis?’, Africa has enormous potential for aquaculture growth, but substantial knowledge gaps about tilapia parasites in many African states remain, which creates associated production and biosecurity risks. For each parasitic group, therefore, the risks of parasite translocation to new regions as tilapia aquaculture industries expand are highlighted

Wintering grounds, population size and evolutionary history of a cryptic passerine species from isotopic and genetic data

Cryptic species pose a particular challenge to biologists in the context of life history investigations because of the difficulty in their field discrimination. Additionally, there is normally a lag in their widespread acceptance by the scientific community once they are formally recognised. These two factors might constrain our ability to properly assess the conservation status of the different species conforming a cryptic complex. In this study, we analysed isotopic and genetic data to shed light into the still unclear wintering grounds, population size and evolutionary history of the Iberian chiffchaff Phylloscopus ibericus, a species included within the common chiffchaff Phylloscopus collybita until two decades ago due to their phenotypic similarity. We used molecular methods to identify spring-migrating Phylloscopus species captured in northern Iberia, and by comparing the Hydrogen isotopic ratios of their claw tips (δ2Hc; which would reflect the signatures of their wintering grounds), we detected that δ2Hc values of Iberian chiffchaffs were similar to willow warblers (Phylloscopus trochilus; a renowned trans-Saharan migrant), and higher than common chiffchaffs (mostly a pre-Saharan migrant). These results strongly support the idea that Iberian chiffchaffs winter in tropical Africa. We additionally reconstructed the phylogeny and evolutionary history of the Iberian chiffchaff's clade using mitochondrial and nuclear markers. Our results revealed relatively high values of nucleotide diversity (and, hence, high Ne) for the species that were greater than the values of the common/Iberian most recent common ancestor. This suggests that the Iberian chiffchaff did not experience strong bottlenecks after diverging from the common chiffchaff approximately one million years ago. Ultimately, our study provides another illustrative example of how isotopic and genetic analysis tools can help to enhance our understanding of avian ecology and evolution.Depto. de Biodiversidad, Ecología y EvoluciónFac. de Ciencias BiológicasTRUEpu

Molecular approaches to trematode systematics: 'best practice' and implications for future study

To date, morphological analysis has been the cornerstone to trematode systematics. However, since the late-1980s we have seen an increased integration of genetic data to overcome problems encountered when morphological data are considered in isolation. Here, we provide advice regarding the ‘best molecular practice’ for trematode taxonomy and systematic studies, in an attempt to help unify the field and provide a solid foundation to underpin future work. Emphasis is placed on defining the study goals and recommendations are made regarding sample preservation, extraction methods, and the submission of molecular vouchers. We advocate generating sequence data from all parasite species/host species/geographic location combinations and stress the importance of selecting two independently evolving loci (one ribosomal and one mitochondrial marker). We recommend that loci should be chosen to provide genetic variation suitable to address the question at hand and for which sufficient ‘useful’ comparative sequence data already exist. Quality control of the molecular data via using proof-reading Taq polymerase, sequencing PCR amplicons using both forward and reverse primers, ensuring that a minimum of 85% overlap exists when constructing consensus sequences, and checking electropherograms by eye is stressed. We advise that all genetic results are best interpreted using a holistic biological approach, which considers morphology, host identity, collection locality, and ecology. Finally, we consider what advances next-generation sequencing holds for trematode taxonomy and systematics