RESUMEN
An intricate interplay between evolutionary and demographic processes has frequently resulted in complex patterns of genetic and phenotypic diversity in alpine lineages, posing serious challenges to species delimitation and biodiversity conservation planning. Here we integrate genomic data, geometric morphometric analyses and thermal tolerance experiments to explore the role of Pleistocene climatic changes and adaptation to alpine environments on patterns of genomic and phenotypic variation in diving beetles from the taxonomically complex Agabus bipustulatus species group. Genetic structure and phylogenomic analyses revealed the presence of three geographically cohesive lineages, two representing trans-Palearctic and Iberian populations of the elevation-generalist A. bipustulatus and another corresponding to the strictly-alpine A. nevadensis, a narrow-range endemic taxon from the Sierra Nevada mountain range in southeastern Iberia. The best-supported model of lineage divergence, along with the existence of pervasive genetic introgression and admixture in secondary contact zones, is consistent with a scenario of population isolation and connectivity linked to Quaternary climatic oscillations. Our results suggest that A. nevadensis is an alpine ecotype of A. bipustulatus, whose genotypic, morphological and physiological differentiation likely resulted from an interplay between population isolation and local altitudinal adaptation. Remarkably, within the Iberian Peninsula, such ecotypic differentiation is unique to Sierra Nevada populations and has not been replicated in other alpine populations of A. bipustulatus. Collectively, our study supports fast ecotypic differentiation and incipient speciation processes within the study complex and points to Pleistocene glaciations and local adaptation along elevational gradients as key drivers of biodiversity generation in alpine environments.
Asunto(s)
Escarabajos , Especiación Genética , Genética de Población , Filogenia , Animales , Escarabajos/genética , Escarabajos/clasificación , Escarabajos/anatomía & histología , Ecotipo , Fenotipo , España , Genotipo , Variación GenéticaRESUMEN
Aquatic pollution derived from metal presence in the Galapagos Islands could affect biodiversity and human health. This research provide a baseline on food safety in commercial fish species of the Galapagos Islands. We sampled muscle tissue of pelagic (Acanthocybium solandri) and demersal (Caulolatilus affinis, Pontinus clemensi, Hyporthodus mystacinus, and Paralabrax albomaculatus) species. Metal and metalloid concentrations per species were analyzed by Inductively Coupled Plasma Optical Spectrometry (ICP-OES). According to the Food and Agriculture Organization (FAO) regulation none of the studied species should be ingested; and according to the European Food Safety Authority (EFSA) regulation, all the studied species were above the Maximum Allowable Concentration (MAC) for Cd. According to EFSA, C. affinis should not be commercialized. Finally, A. solandri, P. clemensi and H. mystacinus do not represent a human health risk since its Margen of Safety (MoS) < 1 for people of up to 100 kg of body weight.
Asunto(s)
Metaloides , Metales Pesados , Perciformes , Humanos , Animales , Evaluación Nutricional , Metales/análisis , Peces , Metales Pesados/análisis , Medición de RiesgoRESUMEN
The Galapagos Islands are one of the best-preserved archipelagos in the world. We sampled individuals of six demersal and three pelagic species. The metal concentration of liver and gonad tissues were analyzed by Inductively Coupled Plasma Optical Spectrometry. Findings suggest none of the pelagic species showed metallic concentrations that could pose a risk to their health or reproductive capacity. S. violacea and P. clemensi Zn levels were higher in liver than in gonads, indicating that these species could be in their reproduction period. Zn risk toxicity for the study species is negligible. High concentrations of Cd were found in the liver of C. princeps, C. affinis and P. albomaculatus which could cause morphological and physiological alterations. We hypothesize that the high metal concentrations found in the demersal species could come from the volcanism of the islands, since no major sources of anthropogenic metal contamination can be found in the archipelago.
Asunto(s)
Metaloides , Metales Pesados , Contaminantes Químicos del Agua , Animales , Monitoreo del Ambiente , Peces , Gónadas/química , Humanos , Hígado/química , Metales Pesados/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
Metal pollution in the marine environment can damage places with exceptional biodiversity such as the Galapagos Islands. For this reason, it is important to evaluate the toxic risk from metals derived from fish consumption and to perform a nutritional assessment. We sampled 20 individuals of demersal (Caulolatilus princeps and Mycteroperca olfax) and pelagic (Thunnus albacares and Seriolella violacea) species. The levels of the toxic elements (Al, B, Ba, Cd, Ni, Pb and Sr), and the macroelements, microelements and trace elements (Ca, Cr, Fe, K, Li, Mn, Mo, Mg, Na, V and Zn) of species muscle tissue were analyzed by Inductively Coupled Plasma Optical Spectrometry (ICP-OES). Demersal species have higher concentrations of Cr, K, Mg and Mo; while pelagic species have higher levels of Zn. M. olfax could potentially cause Cd toxicity so it is recommended not to ingest more than 86 and 73 g of this species (i.e. roughly, one serving) per week for men and women, respectively. None of the species could be marketed in Europe and the USA due to Cd level exceed the allowed limits by EFSA and FAO. Furthermore, the dietary intake of C. princeps is recommended due to its high concentration of Ca, Na, K, Mg and Cr, while T. albacares is recommended for people with Zn deficiency. However, due to the Cd level in C. princeps it is not recommended to ingest more than five servings per week. We attribute the source of metals in the studied fish from the volcanic origin of the islands rather than from human pollution. This is the first study that thoroughly estimate concentration of metals in commercial fish species and its contribution to food security in the Galapagos.