Browsing by Author "Quintero-Galvis, Julian F."

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    Climate change and population persistence in a hibernating marsupial
    (2024) Nespolo, Roberto F.; Quintero-Galvis, Julian F.; Fonturbel, Francisco E.; Cubillos, Francisco A.; Vianna, Juliana; Moreno-Meynard, Paulo; Rezende, Enrico L.; Bozinovic, Francisco
    Climate change has physiological consequences on organisms, ecosystems and human societies, surpassing the pace of organismal adaptation. Hibernating mammals are particularly vulnerable as winter survival is determined by short-term physiological changes triggered by temperature. In these animals, winter temperatures cannot surpass a certain threshold, above which hibernators arouse from torpor, increasing several fold their energy needs when food is unavailable. Here, we parameterized a numerical model predicting energy consumption in heterothermic species and modelled winter survival at different climate change scenarios. As a model species, we used the arboreal marsupial monito del monte (genus Dromiciops), which is recognized as one of the few South American hibernators. We modelled four climate change scenarios (from optimistic to pessimistic) based on IPCC projections, predicting that northern and coastal populations (Dromiciops bozinovici) will decline because the minimum number of cold days needed to survive the winter will not be attained. These populations are also the most affected by habitat fragmentation and changes in land use. Conversely, Andean and other highland populations, in cooler environments, are predicted to persist and thrive. Given the widespread presence of hibernating mammals around the world, models based on simple physiological parameters, such as this one, are becoming essential for predicting species responses to warming in the short term.
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    Genomic diversity and demographic history of the Dromiciops genus (Marsupialia: Microbiotheriidae)
    (2022) Quintero-Galvis, Julian F.; Saenz-Agudelo, Pablo; Amico, Guillermo C.; Vazquez, Soledad; Shafer, Aaron B. A.; Nespolo, Roberto F.
    Three orders represent the South American fauna of marsupials. Of these, Microbiotheria was until recently known as a monotypic genus with the only surviving species Dromiciops gliroides (monito del monte). The recent proposal of a new Dromiciops species (Dromiciops bozinovici), together with new information on the origin and diversification of living microbioterians has changed the prevailing paradigm around the evolutionary history of these emblematic marsupials. Here, we used a RADseq approach to test for evidence of admixture and past or current gene flow among both species of Dromiciops and evaluate the genetic structure within D. gliroides. We analyzed 127 samples of Dromiciops distributed across the known distribution range of both species. We also inferred the joint demographic history of these lineages, thus corroborating the status of D. bozinovici as a distinct species. Demographic history reconstruction indicated that D. bozinovici diverged from D. gliroides around 4my ago and has remained isolated and demographically stable ever since. In contrast, D. gliroides is subdivided into three subclades that experienced recent expansions and moderate gene flow among them (mostly from north to south). Furthermore, genetic distances among populations within D. gliroides were significantly correlated with geographic distances. These results suggest that some of the D. gliroides populations would have survived in glacial refuges, with posterior expansions after ice retreat. Our results have important implications for the sys-tematics of the genus and have profound conservation consequences for the new species, especially considering the fragmentation level of the temperate rainforest.
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    Local adaptation of Dromiciops marsupials (Microbiotheriidae) from southern South America: Implications for species management facing climate change
    (2024) Quintero-Galvis, Julian F.; Saenz-Agudelo, Pablo; D'Elia, Guillermo; Nespolo, Roberto F.
    The two species of the microbiotheriid marsupial genus Dromiciops (Dromiciops bozinovici: "Panchos's monito del monte" and Dromiciops gliroides: "monito del monte") exhibit a marked latitudinal genetic differentiation. Nevertheless, it is unclear whether this differentiation results from neutral processes or can be explained, to some extent, by local adaptation to different environmental conditions. Here, we used an SNP panel gathered by Rad-seq and searched for footprints of local adaptation (putative loci under selection) by exploring genetic associations with environmental variables in the two species of Dromiciops in Chilean and Argentinean populations. We applied three methods for detecting outlier SNPs and two genotype-environment associations approaches to quantify associations between allelic frequencies and environmental variables. Both species display strong genetic structure. D. bozinovici exhibited three distinct genetic groups, marking the first report of such structuring in this species using SNPs. In contrast, D. gliroides displayed four genetic clusters, consistent with previous studies. Both species exhibited an association of their genetic structure with environmental variables. D. bozinovici exhibited significant associations of allelic frequencies with elevation, precipitation during the warmest periods, and seasonality in the thermal regime. For D. gliroides, genetic variation appeared to be associated with more variables than D. bozinovici, including precipitation and temperature-related variables, isothermality, and elevation. All the outlier SNPs were mapped to the D. gliroides reference genome to explore if they fell within functionally known genes. These results represent a necessary first step toward identifying the genome regions that harbor genes associated with climate adaptations in Dromiciops. Notably, we identified genes involved in various functions, including carbohydrate synthesis (ALG8), muscle and neuronal regulation (MEF2D), and stress responses (PTGES3). Ultimately, this study contributes valuable insights that can inform targeted conservation strategies aimed at preserving the genetic diversity of Dromiciops in the face of environmental challenges.
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    Natural history of the relict marsupial Monito del Monte at the most extreme altitudinal and latitudinal location
    (2021) Mejias, Carlos; Castro-Pastene, Carlos A.; Carrasco, Hector; Quintero-Galvis, Julian F.; Soto-Gamboa, Mauricio; Bozinovic, Francisco; Nespolo, Roberto F.
    Until a few years ago, the "monito del monte" (Dromiciops gliroides) was considered the sole surviving species of Microbiotheria, the sister group of Australidelphia (Australian marsupials). However, the recent identification of a new species relegated to the northern range (Dromiciops bozinovici) and newly discovered populations of Dromiciops beyond the known limits for the geographic range demands for new studies in extreme locations. In this report, we describe the northernmost population of D. bozinovici at a high Andean location (Reserva Nacional Altos de Lircay [RNAL], which represents a record of Dromiciops distribution both in latitude [35 degrees S] and in altitude [1696 m a.s.l.]). We live-trapped individuals, performed behavioral observations, and extracted mtDNA (Cytb) for analyzing phylogenetic affinities. Together with confirming the phylogenetic position of RNAL within the D. bozinovici clade, interesting aspects of this isolated population arose, such as the sympatry with a didelphid marsupial (Thylamys elegans), and phylogenetic closeness with populations 300 km southward coastal. Our trapping effort yielded approximately 9.3 individuals/ha, which is relatively high compared with other small mammal populations, but typical for Dromiciops. Using in situ thermographic imaging during a night transect, we detected free-ranging animals running vertically at similar to 3.6 km/h through the logs of mature trees (Nothofagus pumilio), which is fast compared with other small runners (e.g., cursorial rodents), and also compared with Dromiciops from other locations. We compared the critical time to escape, of RNAL individuals which resulted significantly higher than Dromiciops from Nahuelbuta and Valdivia, suggesting that animals from RNAL are more tolerant to human presence than other populations, which is probably due to the high level of isolation of this population. According to the IUCN the northernmost distribution of Dromiciops reaches Cauquenes, thus this report extends the distribution in 120 km to the North East. Interesting aspects, such as hibernation at freezing temperatures and the existence of a viable D. bozinovici population northward of RNAL, warrant further research on this interesting location.
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    The biogeography of Dromiciops in southern South America: Middle Miocene transgressions, speciation and associations with Nothofagus
    (2021) Quintero-Galvis, Julian F.; Saenz-Agudelo, Pablo; Celis-Diez, Juan L.; Amico, Guillermo C.; Vazquez, Soledad; Shafer, Aaron B. A.; Nespolo, Roberto F.
    The current distribution of the flora and fauna of southern South America is the result of drastic geological events that occurred during the last 20 million years, including marine transgressions, glaciations and active vulcanism. All these have been associated with fragmentation, isolation and subsequent expansion of the biota, south of 35 degrees S, such as the temperate rainforest. This forest is mostly dominated by Nothofagus trees and is the habitat of the relict marsupial monito del monte, genus Dromiciops, sole survivor of the order Microbiotheria. Preliminary analyses using mtDNA proposed the existence of three main Dromiciops lineages, distributed latitudinally, whose divergence was initially attributed to recent Pleistocene glaciations. Using fossil-calibrated dating on nuclear and mitochondrial genes, here we reevaluate this hypothesis and report an older (Miocene) biogeographic history for the genus. We performed phylogenetic reconstructions using sequences from two mitochondrial DNA and four nuclear DNA genes in 159 specimens from 31 sites across Chile and Argentina. Our phylogenetic analysis resolved three main clades with discrete geographic distributions. The oldest and most differentiated clade corresponds to that of the northern distribution (35.2 degrees S to 39.3 degrees S), which should be considered a distinct species (D. bozinovici, sensu D'Elia et al. 2016). According to our estimations, this species shared a common ancestor with D. gliroides (southern clades) about similar to 13 million years ago. Divergence time estimates for the southern clades (39.6 degrees S to 42.0 degrees S) ranged from 9.57 to 6.5 Mya. A strong genetic structure was also detected within and between clades. Demographic analyses suggest population size stability for the northern clade (D. bozinovici), and recent demographic expansions for the central and southern clades. All together, our results suggest that the diversification of Dromiciops were initiated by the Middle Miocene transgression (MMT), the massive marine flooding that covered several lowlands of the western face of Los Andes between 37 and 48 degrees S. The MMT resulted from an increase in global sea levels at the Miocene climatic optimum, which shaped the biogeographic origin of several species, including Nothofagus forests, the habitat of Dromiciops.