RESUMO
Humpback whales, a species of baleen whale occurring in all oceans globally, undergo seasonal migration between their breeding grounds in tropical warm waters and high latitude feeding grounds. Using multiple years of satellite tracking data, we modeled the effect of oceanic conditions on the movement behaviour of 42 humpback whales belonging to the Southeastern Pacific population (also known as Breeding Stock G) during their migration from breeding grounds in Costa Rica, Panama and Ecuador to feeding grounds in waters around the Antarctic Peninsula. We report evidence that during their migration, humpback whales engage in a movement behaviour frequently associated with feeding, and that this behaviour was more likely to occur in relatively more productive waters. We show that whales partly rely on cues they perceive in their immediate environment to initiate their southward migration, but also on their memory of oceanic conditions on their feeding grounds, timing their arrival with the complete melting of sea ice which triggers a bloom of krill in the Antarctic Ocean. Overall, our findings suggest that humpback whales integrate information they gather from their immediate environment to predict the oceanic conditions at distant locations and adjust the timing of their migration, maximizing their interaction with their preys. However, it is unclear if humpback whales will fully succeed in tracking their preys in a rapidly changing climate and ensure the long-term persistence of the species.
Assuntos
Migração Animal , Mudança Climática , Jubarte , Animais , Migração Animal/fisiologia , Jubarte/fisiologia , Oceano Pacífico , Estações do Ano , Costa Rica , Panamá , Regiões Antárticas , Equador , Comportamento Alimentar/fisiologiaRESUMO
During parasitological surveys of marine fishes and zooplankton in localities of the Northwestern Pacific coast of Mexico, 28 Gafftopsail pompano (Trachinotus rhodopus Gill) and 50 mysid crustaceans (Metamysidopsis frankfiersi Hendrickx & Hernández-Payán) we identified to be infected with adults and cystacanths, respectively of an acanthocephalan morphologically corresponding to the genus Rhadinorhynchus Lühe, 1911. DNA sequences of the small (SSU) and large (LSU) subunits of ribosomal DNA, and cytochrome c oxidase subunit 1 (cox 1) from mitochondrial DNA were obtained. Phylogenetic analyses revealed that the newly sequenced individuals in a clade with Rhadinorhynchus sp. from carangids in other localities of the Pacific coast of Mexico; together, all these individuals formed an independent lineage that is recognized herein as a new species, Rhadinorhynchus trachinoti n. sp. The new species is morphologically distinguished from the other 38 congeners by having a long and cylindrical proboscis armed with 12 longitudinal rows bearing 16-18 hooks each. The ecological information gathered from the parasites, together with genetic evidence, confirms that the Gafftopsail pompano is the definitive host of R. trachinoti n. sp., while mysid crustaceans serve as the intermediate host. Current records also indicate that R. trachinoti n. sp. is distributed along the Pacific coast of Mexico, from Mazatlán, Sinaloa in the north to Puerto Angel, Oaxaca in the south. This distribution aligns with the Mexican Coastal Current, which extends from the Gulf of Tehuantepec in Oaxaca to the entrance of the Gulf of California and southern Baja California.
Assuntos
Acantocéfalos , Filogenia , Especificidade da Espécie , Animais , Acantocéfalos/classificação , Acantocéfalos/genética , Acantocéfalos/anatomia & histologia , México , Oceano Pacífico , Complexo IV da Cadeia de Transporte de Elétrons/genéticaRESUMO
Heterogorgia abdita sp. nov. is a newly identified mesophotic octocoral species collected at Tigre shoal off Santa Elena Peninsula (Pacific Costa Rica). The new species is described based on distinctive morphological characters that classify it within the genus Heterogorgia. It is characterised by its conspicuous small branching colony with prominent calyces and thin branches. While its scleroma aligns with the genus, the presence of club-like spindles is notable, as these have previously been observed only in the sole Atlantic Heterogorgia species. This study enhances our understanding of the intriguing genus Heterogorgia and contributes to the knowledge of octocoral biodiversity within the Área de Conservación Guanacaste north Pacific Costa Rica and the broader marine biodiversity of the eastern tropical Pacific.
Assuntos
Distribuição Animal , Antozoários , Animais , Antozoários/anatomia & histologia , Antozoários/classificação , Oceano Pacífico , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Tamanho Corporal , Tamanho do Órgão , Costa Rica , Masculino , Feminino , Ecossistema , BiodiversidadeRESUMO
A new species of the Aulopidae is described from the waters of southern Ecuador and northern Peru. Aulopus chirichignoae sp. nov. was previously confused with Aulopus bajacali Parin & Kotlyar, 1984, but it differs from this species by a significantly marked elongation of the dorsal fin rays in males (absent in females), a smaller head, modal differences in dorsal and anal ray counts (15 vs 14 and 11 vs 12, respectively), a higher number of vertebrae (50-51 vs 47-49), and color differences, especially on the dorsal fin. DNA barcoding analysis supported the status of new species, evidencing a 4.2% and 2.8% divergence with Aulopus filamentosus (Bloch, 1792) and A. bajacali, respectively. A sequence of an Aulopus sp., collected in the Tropical Eastern Pacific, matches the new species with only a 0.4% divergence, indicating that Aulopus chirichignoae sp. nov. is distributed at least as far north as the Paramount Seamount at 3°20.35'N, ca. 400 km north of the Galápagos Islands.
Assuntos
Distribuição Animal , Tamanho Corporal , Animais , Masculino , Feminino , Oceano Pacífico , Equador , Peru , Tamanho do Órgão , Filogenia , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , EcossistemaRESUMO
Here I describe Aberrapex panamensis sp. nov., a parasite of the rough eagle ray Aetomylaeus asperrimus from the eastern Pacific coast of Panama, and Aberrapex catarinensis sp. nov., found in Myliobatis goodei off southern coast of Santa Catarina, Brazil. Aberrapex panamensis sp. nov. is the second record of Aberrapex Jensen, 2001 for the eastern Pacific Ocean and A. catarinensis sp. nov. is the fifth species of the genus registered in southwestern Atlantic Ocean. The two new species are morphologically distinct from all their congeners. Aberrapex panamensis sp. nov. and A. catarinensis sp. nov. can be distinguished from the majority of their congeners by the microthrix pattern on the scolex surface, number of proglottids and testes, length and width of the scolex, uterus extension, and presence and extension of an external seminal vesicle. The description of these two new species of lecanicephalideans expands the knowledge of this cestode order, with A. panamensis sp. nov. being the third species of the genus reported from Aetomylaeus Garman, and A. catarinensis sp. nov. being the sixth species of Aberrapex reported from Myliobatis Cuvier.
Assuntos
Distribuição Animal , Cestoides , Rajidae , Animais , Feminino , Masculino , Rajidae/anatomia & histologia , Rajidae/classificação , Cestoides/classificação , Cestoides/anatomia & histologia , Brasil , Tamanho do Órgão , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Tamanho Corporal , Panamá , Oceano PacíficoRESUMO
Caymanostellidae is a group of rarely collected and morphologically unusual sea stars that have been exclusively encountered on wood falls in the deep sea. There are currently three genera and seven species described, occurring in the Atlantic, Pacific and Indian Oceans with a depth range between 418 and 6780 m. Three new species are here described from specimens collected from wood falls in multiple localities across the Pacific margin of Costa Rica and near the Gulf of California (Mexico): Caymanostella scrippscognaticausa sp. nov., Caymanostella davidalani sp. nov. and Caymanostella loresae sp. nov. These records expand the known geographical distribution of caymanostellids and constitute their first report from wood falls found at methane seeps. This study also includes the first descriptions of early-stage juvenile caymanostellids and reveals that traits previously considered useful for diagnosis might represent intraspecific and ontogenetic variability, with important consequences for caymanostellid taxonomy.
Assuntos
Distribuição Animal , Estruturas Animais , Tamanho Corporal , Estrelas-do-Mar , Animais , Oceano Pacífico , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Estrelas-do-Mar/classificação , Estrelas-do-Mar/anatomia & histologia , Costa Rica , Tamanho do Órgão , México , EcossistemaRESUMO
Using samples of talitrid amphipods collected on the coast of Chile, we describe two new monotypic genera characterized by particular types of sexual dimorphism, and we report the first record of the genus Platorchestia Bousfield, 1982 in the southeastern Pacific coast. In the subfamily Platorchestiinae, the genus Atacamorchestia gen. nov. and its new species Atacamorchestia atacamensis sp. nov. was collected in marine rocky coasts, in several localities in northern Chile. This new taxon is characterized principally by presence of T setae in male appendages, a feature shared with the genus Vallorchestia from Australia, but with a different distribution of these structures. The first specimens of Platorchestia in the Southeastern Pacific were obtained in Antofagasta, northern Chile, however they were identified only to genus level because a more in-depth taxonomic analysis will be necessary to determine their status. Finally, in the subfamily Talitrinae, Lafkenorchestia gen. nov. and its new species Lafkenorchestia oyarzuni sp. nov. were found on rocky marine shores and in estuaries in southern Chile, between La Araucania and Los Lagos regions. This new taxon is characterized by distinct modifications in basis and merus of male pereopod 7, showing some morphological similarities with the New Zealand genera Subantarctorchestia and Pictonorchestia. For each species, descriptions and illustrations are presented.
Assuntos
Anfípodes , Distribuição Animal , Tamanho Corporal , Animais , Masculino , Chile , Feminino , Anfípodes/classificação , Anfípodes/anatomia & histologia , Tamanho do Órgão , Estruturas Animais/anatomia & histologia , Estruturas Animais/crescimento & desenvolvimento , Oceano Pacífico , EcossistemaRESUMO
The association of parasites and diatoms has been previously reported as an important mechanism to control bacteria and parasites to avoid resistance to chemical usage. The aim of this study was to investigate the association between diatoms genus and parasites within the gastrointestinal compartments (GICs) of commercial fish in fisheries of the marine Pacific coast of Colombia (Buenaventura). A total of 104 GICs from marine fish were sampled. The GICs analysis revealed 14 diatom genera (N = 14). The most prevalent were Coscinodiscus spp., which was present in 58/104 samples, 55.8% [95% CI = 37.5-62.1%]; Cyclotella spp., 28/104, 26.9% [95% CI = 0-25%]; Paralia spp., 26/104, 25% [95% CI = 12.5-44.8%]; Gyrosigma spp., 11/104, 10.6% [95% CI = 0-33.3%]; Navicula spp., 11/104, 10.6%, [95% CI = 0-20.7%]. The GICs analysis revealed a diversity of genera parasites. The most prevalent were Ameboid cysts, 25/104, 24% [95% CI = 12.5-48.3%]; Eimeria spp., 11/104, 10.6% [95% CI = 10.3-15.7%]; Anisakis spp., 29/104, 27.1% [95% CI = 27.1 (SD±12.9%)]. This is the first report concerning diatoms and parasites association in fish from the Pacific Coast of Colombia and highlights the relevance of Coscinodiscus spp. and Gyrosigma spp. as important diatoms and potential candidates for studying pharmaceutical action in aquaculture. Further studies about diatoms-parasites association in aquaculture are required.
Assuntos
Diatomáceas , Doenças dos Peixes , Peixes , Animais , Colômbia/epidemiologia , Peixes/parasitologia , Doenças dos Peixes/parasitologia , Doenças dos Peixes/epidemiologia , Pesqueiros , Oceano PacíficoRESUMO
Background: The morphology and hunting behavior of thresher sharks make them easily distinguishable. These species are distributed across the Tropical Pacific Ocean feeding on squid and small fish. However, ontogenetic changes in their feeding strategies and habitat use are still unknown in this region. Methods: We examined the δ13C and δ15N signatures in vertebral collagen from populations of Alopias pelagicus and Alopias superciliosus inhabiting the Galapagos Marine Reserve, focusing on three maturity stages: neonate, juvenile and adult. The vertebrae samples were taken from the seizure of illegal fishing activities carried out by a foreign fleet within the Galapagos archipelago. A total of thirty-three vertebrae from A. pelagicus and twenty-one from A. superciliosus were analyzed. Results: Both species displayed significant differences in their δ15N values (p < 0.001), but not in δ13C (p = 0.230), suggesting a similar habitat use, but different prey consumption. Throughout their ontogeny, A. pelagicus displayed isotopic differences (p < 0.001), where neonates showed lower δ13C values and higher δ15N values compared to juveniles, probably because they still reflect the isotopic signatures of their mothers even after the first year of life. This study highlights trophic differences between both species, accompanied by an ontogenetic variation in A. pelagicus, aspects that allow us to understand the role of these species within the dynamics of the Eastern Tropical Pacific ecosystem.
Assuntos
Comportamento Alimentar , Tubarões , Animais , Tubarões/metabolismo , Tubarões/crescimento & desenvolvimento , Tubarões/fisiologia , Comportamento Alimentar/fisiologia , Equador , Isótopos de Carbono/análise , Isótopos de Carbono/metabolismo , Isótopos de Nitrogênio/análise , Oceano Pacífico , Ecossistema , Coluna Vertebral , Colágeno/metabolismoRESUMO
Abstract Introduction: Chacón-Monge et al. (2024) sought to test the accuracy of DNA barcoding for species identification in Pacific Central American shallow water echinoderms. They used cytochrome c oxidase I (COI) sequences derived from new material collected as part of the BioMar-ACG project in Costa Rica. Using their set of 348 echinoderm sequences, they compared species identification results from two online platforms: the National Center for Biotechnology Information (NCBI) GenBank using the nucleotide Basic Local Alignment Search Tool (BLASTn), and the Barcode of Life Data Systems (BOLD) Identification Engine. Objective: The present article is a response to their results and conclusions. Methods: We reinterpreted the results from the authors' Appendix 2 to enable an objective comparison between the BOLD Identification Engine and BLASTn in GenBank. Results: While the authors found that both platforms were limited by the number of reference sequences available in their respective databases, they concluded that GenBank outperformed BOLD for identification; however, we identify several methodological flaws in their analysis. These include pseudoreplication amongst query sequences, contaminated sequences stemming from sampling errors, and a lack of standardization when interpreting results from the two platforms. Their assessment of the BOLD Identification Engine was also limited by improper selection of a reference database. Conclusion: Addressing these errors, we reinterpret their results and demonstrate that there is no difference in performance between the two platforms.
Resumen Introducción: Chacón-Monge et al. (2024) intentaron probar la precisión de los códigos de barras de ADN para identificar especies de equinodermos de aguas poco profundas del Pacífico Centroamericano. Para ello, utilizaron secuencias de citocromo c oxidasa I (COI) provenientes de material recolectado recientemente como parte del proyecto BioMar-ACG en Costa Rica. Utilizando 348 secuencias de equinodermos, compararon los resultados de identificación de especies de dos plataformas en línea: GenBank del Centro Nacional de Información Biotecnológica (NCBI) empleando la herramienta de búsqueda de alineación local básica de nucleótidos (BLASTn) y la herramienta de identificación del Sistema de Datos del Código de Barras de la Vida (BOLD). Objetivo: El presente artículo es una respuesta a sus resultados y conclusiones. Métodos: Reinterpretamos los resultados presentados por los autores en Apéndice 2 para comparar objetivamente el sistema de identificación de BOLD y el de BLASTn en GenBank. Resultados: Si bien los autores encontraron que ambas plataformas estaban limitadas por la cantidad de secuencias de referencia disponibles en sus bases de datos, concluyeron que GenBank superó a BOLD en la identificación de especies; sin embargo, notamos varias fallas metodológicas en su análisis. Estas incluyeron la pseudorreplicación entre las secuencias consultadas, el uso de secuencias contaminadas derivadas de errores de muestreo y falta de estandarización al interpretar los resultados de las dos plataformas. Su evaluación del sistema de identificación de BOLD se vio limitada por la selección inadecuada de una base de datos de referencia. Conclusión: Teniendo en cuenta estos errores, reinterpretamos sus resultados y demostramos que no existe una diferencia significativa en el rendimiento de ambas plataformas.
Assuntos
Equinodermos/classificação , Código de Barras de DNA Taxonômico , Oceano Pacífico , Bases de Dados de Ácidos NucleicosRESUMO
A new species of bothriocephalid cestode in the genus Anantrum is described from the intestine of the shorthead lizardfish Synodus scituliceps from the north Pacific coast of Costa Rica. The new species is described based on an integrative taxonomic approach that includes the use of light and scanning electron microscopy, 28S rDNA sequencing, and phylogenetic analysis. Anantrum gallopintoi sp. nov. is the third known member of this genus and can be distinguished from A. tortum (Linton, 1905) and A. histocephalum Jensen & Heckmann, 1977 by a combination of morphological and ecological traits and, in particular, by having a vaginal sphincter, different number of testes, and different type host and type locality. The molecular analysis and the phylogenetic reconstructions supported its status as a new taxon placing it within a well-supported separate branch of Anantrum spp. subclade. According to the present finding, S. scituliceps represents a new host record and Costa Rica a new geographical record for Anantrum species, and, in general, for a bothriocephalid cestode.
Assuntos
Cestoides , Infecções por Cestoides , DNA Ribossômico , Doenças dos Peixes , Filogenia , Animais , Costa Rica , Cestoides/classificação , Cestoides/genética , Cestoides/anatomia & histologia , Cestoides/isolamento & purificação , Infecções por Cestoides/veterinária , Infecções por Cestoides/parasitologia , Doenças dos Peixes/parasitologia , DNA Ribossômico/genética , DNA de Helmintos/genética , RNA Ribossômico 28S/genética , Intestinos/parasitologia , Análise de Sequência de DNA , Oceano Pacífico , Microscopia , Microscopia Eletrônica de Varredura/veterináriaRESUMO
The giant kelp Macrocystis pyrifera is categorized as a keystone species, forming highly productive forests that provide ecosystem services and host a remarkable marine biodiversity of macro and microorganisms. The association of microorganisms with the algae is close and can be functionally interdependent. The Magellan Strait, a natural marine passage between the Atlantic and Pacific oceans, harbours extensive giant kelp forests. However, information related to the diversity of bacterial communities in this region is still scarce. In this study, 16S rRNA gene metabarcoding was used to characterize the diversity and composition of bacterial communities associated with apical blades and sporophylls of M. pyrifera from different sites (Bahía Buzo, San Gregorio, and Buque Quemado). Additionally, data from satellites and reanalysis, as well as tide data, were used to characterize the environmental variability. The findings revealed discernible local variations in bacterial taxa across sampling sites, with consistent dominance of Proteobacteria, Verrucomicrobia, Bacteroidetes, and Planctomycetes. Furthermore, a distinctive bacterial community structure was identified between apical and sporophyll blades of M. pyrifera. This research marks the inaugural characterization of bacterial community diversity and composition associated with M. pyrifera in the remote and understudied sub-Antarctic region of the Magellan Strait.
Assuntos
Bactérias , Macrocystis , RNA Ribossômico 16S , RNA Ribossômico 16S/genética , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Macrocystis/microbiologia , Biodiversidade , Filogenia , Oceano Pacífico , Microbiota , Kelp/microbiologia , Água do Mar/microbiologia , Ecossistema , Oceano Atlântico , Proteobactérias/genética , Proteobactérias/classificação , Proteobactérias/isolamento & purificação , Bacteroidetes/genética , Bacteroidetes/classificação , Bacteroidetes/isolamento & purificação , Verrucomicrobia/genética , Verrucomicrobia/classificação , Verrucomicrobia/isolamento & purificação , DNA Bacteriano/genéticaRESUMO
The tropical eastern Pacific (TEP) is a biogeographic region with a substantial set of isolated oceanic islands and mainland shoreline habitat barriers, as well as complex oceanographic dynamics due to major ocean currents, upwelling areas, eddies, and thermal instabilities. These characteristics have shaped spatial patterns of biodiversity between and within species of reef and shore fishes of the region, which has a very high rate of endemism. Scorpaenodes xyris, a small ecologically cryptic reef-dwelling scorpionfish, is widely distributed throughout the TEP, including all the mainland reef areas and all the oceanic islands. This wide distribution and its ecological characteristics make this species a good model to study the evolutionary history of this type of reef fish across the breadth of a tropical biogeographical region. Our evaluation of geographic patterns of genetic (mitochondrial and nuclear) variation shows that S. xyris comprises two highly differentiated clades (A and B), one of which contains four independent evolutionary subunits. Clade A includes four sub-clades: 1. The Cortez mainland Province; 2. The Revillagigedo Islands; 3. Clipperton Atoll; and 4. The Galapagos Islands. Clade B, in contrast, comprises a single unit that includes the Mexican and Panamic mainland provinces, plus Cocos Island. This geographical arrangement largely corresponds to previously indicated regionalization of the TEP. Oceanic distances isolating the islands have produced much of that evolutionary pattern, although oceanographic processes likely have also contributed.
Assuntos
Variação Genética , Filogenia , Animais , Oceano Pacífico , Perciformes/genética , Perciformes/classificação , DNA Mitocondrial/genética , Filogeografia , Biodiversidade , Evolução Molecular , Núcleo Celular/genética , Análise de Sequência de DNA/métodosRESUMO
Perkinsus marinus, a parasite myzozoa native from the Atlantic Ocean, has spread across various bivalve species in the Pacific Ocean. In the Gulf of California, clams like Larkinia grandis and Leukoma grata have become a secondary fishery, experiencing demand. During annual sampling (August 2017 - July 2018, n = 30/month), the Ray's fluid thioglycollate medium (RFTM) revealed presumptive hypnospores of Perkinsus sp. in L. grandis, with a low parasite prevalence (4.16%) and density (≤ 3.14 hypnospores g-1 tissue). From summer 2020 to summer 2021, P. marinus was seasonally identified in L. grata via staining and PCR tests, showing mean prevalence and density of 48.33% and 48 hypnospores g-1 tissue, respectively. The infection level was light in both clams. This parasite's presence in these new hosts within the southeastern Gulf of California confirms its ability to expand into non-native places, signaling a need for intervention strategies in managing and transporting mollusk species within the region.
Assuntos
Alveolados , Bivalves , Animais , Alveolados/isolamento & purificação , Alveolados/classificação , Alveolados/genética , Bivalves/parasitologia , Oceano Pacífico , CaliforniaRESUMO
El Niño events, the warm phase of the El Niño Southern Oscillation, facilitate the movement of warm surface waters eastwards across the Pacific Ocean. Marine organisms transported by these waters can act as biological corridors for water-borne bacteria with attachment abilities. El Niño events have been hypothesized as driving the recent emergence of Vibrio parahaemolyticus (Vp) variants, marine bacterium causing gastroenteritis, in South America, but the lack of a robust methodological framework limited any further exploration. Here, we introduce two new analysis approaches to explore Vp dynamics in South America, which will be central to uncovering Vp dynamics in the future. Distributed non-linear lag models found that strong El Niño events increase the relative probability of Vp detection in Peru, with a 3-4-month lag time. Machine learning found that the presence of a specific gene (vopZ) involved in attachment to plankton in a pandemic Vp clone in South America was temporally associated with strong El Niño events, offering a possible strategy for survival over long-range dispersal, such as that offered by El Niño events. Robust surveillance of marine pathogens and methodological development are necessary to produce resolute conclusions on the effect of El Niño events on water-borne diseases.
Assuntos
El Niño Oscilação Sul , Vibrio parahaemolyticus , Vibrio parahaemolyticus/genética , Peru , Oceano Pacífico , Vibrioses/microbiologia , Água do Mar/microbiologia , Humanos , Aprendizado de MáquinaRESUMO
Coral reefs are maintained by a balance between formation (calcifiers) and destructive processes (dissolution and erosion). In eastern tropical Pacific reefs, Porites genus is the second-largest contributor to CaCO3 production, but is affected by bioerosion. In this study, we evaluate the interaction between Lithophaga and Porites in an island reef in the Mexican Pacific by quantifying bioerosion rate, its impact on CaCO3 production, and contrasting growth models. To achieve this, Porites lobata colonies were collected to evaluate calcification and CaCO3 production. Shells of Lithophaga (Leiosolenus plumula) were extracted from corals, and age and length fed into a growth model. Our results indicate a high bioerosion rate (21.9 ± 4.1 %), representing 8.3 % of overall CaCO3 production. Bivalves' age (8 y) was less than corals (12.6 y), and cohort analysis indicates an intense recruitment. We associate this with high productivity derived from the island's oceanography, promoting nutrient enrichment, a plausible scenario for reefs under eutrophication conditions.
Assuntos
Antozoários , Carbonato de Cálcio , Recifes de Corais , Animais , Bivalves , Oceano Pacífico , MéxicoRESUMO
Spiral valves from specimens of the giant electric ray Narcine entemedor Jordan & Starks, 1895 were examined in search of tapeworms at 2 localities of the Mexican tropical Pacific Ocean. Acanthobothrium oceguerai n. sp. is described herein based on material from Ventanilla, Oaxaca and from Acapulco Bay, Guerrero. The new species is a category 6 species, distinguished by being apolytic, retaining proglottids on the strobila until they are gravid, having strobila of 166-322 proglottids, having a small scolex and very long bothridia relative to the scolex, and having abaxial prongs that are short and thin in comparison to the axial prongs, which are longer and more robust. Acanthobothrium oceguerai n. sp. can be differentiated from other members of category 6 by the hooks, which are shorter, more robust, and smaller than those of the other members of this category. The phylogenetic analysis based on the 28S rRNA locus placed Acanthobothrium oceguerai n. sp. as sister to an unidentified species of larval Acanthobothrium from Philadelphia, Pennsylvania. In addition, sequences of the mitochondrial cytochrome oxidase subunit I gene and nuclear 18S rDNA were generated to provide support for future taxon sampling. Acanthobothrium oceguerai n. sp. is the fifth species of cestode reported from N. entemedor in the tropical eastern Pacific.
Assuntos
Cestoides , Infecções por Cestoides , Filogenia , Animais , Cestoides/classificação , Cestoides/genética , Cestoides/anatomia & histologia , Cestoides/ultraestrutura , Cestoides/isolamento & purificação , Infecções por Cestoides/veterinária , Infecções por Cestoides/parasitologia , México , Oceano Pacífico , DNA de Helmintos/química , DNA de Helmintos/isolamento & purificação , RNA Ribossômico 28S/genética , DNA Ribossômico/química , Complexo IV da Cadeia de Transporte de Elétrons/genética , RNA Ribossômico 18S/genéticaRESUMO
The planktonic dinoflagellate genus Centrodinium has been understudied, with the type species C. elongatum remaining undocumented since the original description. Here, we report C. elongatum isolated from Mazatlán, Mexican Pacific. In the chains, the posterior daughter cell with an incomplete apical horn shows the morphology of C. elongatum, while the anterior daughter cell with complete epitheca corresponds to C. pulchrum. For the first time, a species of Centrodinium sensu stricto (highly laterally flattened species with horns) was cultured. An unarmored life stage, known as Murrayella ovalis, derived from the spheroplast after ecdysis. In the rDNA molecular phylogenies, C. elongatum (=C. pulchrum) nested as basal to morphologically similar species (C. eminens and C. intermedium) and as a sister group of a former Murrayella species, C. punctatum. C. elongatum differs from C. eminens and C. intermedium in the chain formation, second apical (2') plate not being divided, horns with coarse poroid ornamentation, and missing prominent distal spinules. The taxonomy of Centrodinium sensu stricto is revised, with a discussion in the identities of C. complanatum, C. eminens, and C. maximum. The name C. deflexum is restored as a senior synonym of C. intermedium and C. ovale.
Assuntos
DNA Ribossômico , Dinoflagellida , Filogenia , Dinoflagellida/classificação , Dinoflagellida/genética , DNA Ribossômico/genética , DNA de Protozoário/genética , México , Oceano Pacífico , Análise de Sequência de DNARESUMO
The rise of the Isthmus of Panama separated the populations of many marine organisms, which then diverged into new geminate sister species currently living in the Eastern Pacific Ocean and the Caribbean Sea. However, we know very little about how such evolutionary divergences of host species have shaped the compositions of their microbiomes. Here, we compared the microbiomes of whole-body and shell-surface samples of geminate species of marine gastropods in the genera Cerithium and Cerithideopsis to those of congeneric outgroups. Our results suggest that the effects of ~3 million years of separation and isolation on microbiome composition varied among host genera and between sample types within the same hosts. In the whole-body samples, microbiome compositions of geminate species pairs tended to be similar, likely due to host filtering, although the strength of this relationship varied among the two groups and across similarity metrics. Shell-surface microbiomes show contrasting patterns, with co-divergence between the host taxa and a small number of microbial clades evident in Cerithideopsis but not Cerithium. These results suggest that (i) isolation of host populations after the rise of the Isthmus of Panama affected microbiomes of geminate hosts in a complex and host-specific manner, and (ii) host-associated microbial taxa respond differently to vicariance events than the hosts themselves.IMPORTANCEWhile considerable work has been done on evolutionary divergences of marine species in response to the rise of the Isthmus of Panama, which separated two previously connected oceans, how this event shaped the microbiomes of these marine hosts remains poorly known. Using whole-body and shell-surface microbiomes of closely related gastropod species from opposite sides of the Isthmus, we show that divergences of microbial taxa after the formation of the Isthmus are often not concordant with those of their gastropod hosts. Our results show that evolutionary responses of marine gastropod-associated microbiomes to major environmental perturbations are complex and are shaped more by local environments than host evolutionary history.
Assuntos
Gastrópodes , Microbiota , Animais , Gastrópodes/microbiologia , Panamá , Filogenia , Organismos Aquáticos/microbiologia , Organismos Aquáticos/classificação , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Oceano Pacífico , Evolução BiológicaRESUMO
The Tropical Indo-Pacific (TIP) includes about two thirds of the world's tropical oceans and harbors an enormous number of marine species. The distributions of those species within the region is affected by habitat discontinuities and oceanographic features. As well as many smaller ones, the TIP contains seven large recognized biogeographic barriers that separate the Red Sea and Indian Ocean, the Indian from the Pacific Ocean, the central and eastern Pacific, the Hawaiian archipelago, the Marquesas and Easter Islands. We examined the genetic structuring of populations of Cirrhitichthys oxycephalus, a small cryptic species of reef fish, across its geographic range, which spans the longitudinal limits of the TIP. We assessed geographic variation in the mitochondrial cytb gene and the nuclear RAG1 gene, using 166 samples collected in 46 localities from the western to eastern edges of the TIP. Sequences from cytb show three well-structured groups that are separated by large genetic distances (1.58-2.96%): two in the Tropical Eastern Pacific (TEP), one at Clipperton Atoll another occupying the rest of that region and the third that ranges across the remainder of the TIP, from the central Pacific to the Red Sea and South Africa. These results indicate that the ~4,000 km wide Eastern Pacific Barrier between the central and eastern Pacific is an efficient barrier separating the two main groups. Further, the ~950 km of open ocean that isolates Clipperton Atoll from the rest of the TEP is also an effective barrier. Contrary to many other cases, various major and minor barriers from the Central Indo-Pacific to the Red Sea are not effective against dispersal by C. oxycephalus, although this species has not colonized the Hawiian islands and Easter Island. The nuclear gene partially supports the genetic structure evident in cytb, although all haplotypes are geographically mixed.