Examinando por Autor "Rivera, Reinaldo"

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    Biogeographic Insights Into the Late Miocene Diversification of the Giant Deep-Ocean Amphipod Eurythenes
    (Wiley, 2025) Gonzalez, Carolina E; Weston, Johanna N. J; Rivera, Reinaldo; Oliva, Marcelo; Escribano, Ruben; Ulloa, Osvaldo
    Mechanisms driving the spatial and temporal patterns of species distribution in the Earth's largest habitat, the deep ocean, remainlargely enigmatic. The late Miocene to the Pliocene (~23–2.58 Ma) is a period that was marked by significant geological, climatic,and oceanographic changes. This transitional period spurred widespread species diversification, particularly among widely dis-tributed benthic scavengers, such as amphipods. Here, we take step toward understanding the long-term evolutionary processesof amphipod colonization and diversification in the deep ocean by focusing on the model genus Eurythenes S. I. Smith in Scudder,1882. These large-bodied scavengers play key roles in benthic communities. We constructed a time-calibrated phylogeny usingtwo mitochondrial DNA genes by analyzing publicly available data on 14 species of Eurythenes across a global depth range from839 to 8081 m. The resulting phylogenetic tree reveals a diverse clade, with a common ancestor originating around 11.81 Ma. Agradual increase in the effective population size of Eurythenes was observed, particularly during the Pliocene (~4 Ma). The netdiversification rate remained almost constant, with slight increases between the Miocene and Pliocene (~8–4 Ma), and most newspecies appeared during the latter period. Additionally, reconstruction of the ancestral area suggested that the common ancestorof Eurythenes had a global distribution. A combination of dispersal and sympatric processes, along with environmental factors,such as changes in ocean temperature and sea level, contributed to the present biogeographic distribution of these species. Ourfindings highlight the importance of historical events, such as plate tectonics and changes in deep-water circulation, in drivingthe rapid speciation of Eurythenes and underscore their essential role in shaping deep-ocean biodiversity
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    Environmental Stability Drives and Maintains the Global Patterns of Phylogenetic Endemism in the Marine Realm
    (Wiley, 2025) Rivera, Reinaldo; Gonzalez, Carolina E; Hidalgo, Pamela; Urbina, Mauricio A; Escribano, Ruben
    Aim: Endemism is a critical aspect of biological diversity, yet the mechanisms driving it remain unclear. The leading hypoth-esis posits that prolonged environmental stability fosters speciation and reduces extinction rates, promoting endemism. Whileterrestrial studies exist, marine environments remain underexplored. This study analysed the global distribution and drivers ofphylogenetic endemism in two marine taxa: Calanidae copepods and Blenniidae fish.Location: Global.Time Period: From the Last Glacial Maximum (LGM, past 24,000 years) to the current period.Taxa: Calanidae copepods and Blenniidae fish.Methods: We assessed taxonomic and phylogenetic diversity, endemism and areas of paleo- and neo-endemism usingCategorical Analysis of Neo- and Paleo-Endemism and Piecewise Structural Equation Modelling to evaluate the influence ofpresent-day and historical environmental variables.Results: Results showed consistent diversity patterns and significant endemism hotspots, with Calanidae in the SouthernHemisphere and Blenniidae in the Northern Hemisphere. Tropical regions, particularly the Indonesian-Australian Archipelago(IAA), exhibited high species richness and endemism for both groups. Paleo- endemism was observed in the Pacific for Calanidaeand the IAA for Blenniidae, suggesting that these areas are either relict diversity centres or diversification hubs.Main Conclusions: The Mediterranean and Caribbean Seas emerged as biodiversity cradles for Calanidae and Blenniidae re-spectively. Phylogenetic endemism is driven by both historical and contemporary factors, with centres of endemism emergingin regions where past environmental fluctuations have been moderate (hypothesis 1) and where cold, productive ocean currentsfoster the development of endemic areas (hypothesis 2). These findings underscore the importance of historical stability in oceantemperatures in shaping phylogenetic endemism, indicating that long-term environmental stability sustains marine endemism