Research

I am broadly interested in understanding the processes that  have shaped diversity in Chilean ecosystems. To do so, I use multiple resources, including GIS-based tools, statistical phylogeographic methods, and next generation sequencing data, to test hypotheses about the factors that affect the distribution of genetic and phenotypic diversity, using fish and insects as model systems.

Current Projects

Phylogeography and evolution of the ground beetle genus Ceroglossus

    Ceroglossus ground beetles are a group of medium-sized, beautifully colored beetles that live mainly in the temperate forest of Chile, but that can also be found in Argentina, in areas with Nothofagus-type forest. The genus has few, but phenoypically diverse species that tend to distribute sympatrically, and although only 8-10 species has been recognized, nearly a hundred subspecies have been described. 

    One of my goals is to establish a robust phylogenetic hypothesis for the genus and investigate the levels of population divergence within nominal species to evaluate the possibility that at least some of the described subspecies might actually be species-level entities.

    To reach this goal, I collected specimens across the entire range of the genus for molecular analyses. By obtaining mitochondrial DNA data (the COI gene) and Rad-seq data (SNPs), I expect to build a robust phylogeny and conduct species delimitation analyses.

    This first step is fundamental in order to explore other more general questions about the processes underlying the patterns of genetic and phenotypic diversity that characterize this genus (See below).

    Recently, and as a parallel project, I confirmed the close relationship between two less-known and geographically restricted species (C. ochsenii and C. guerini) and the more widely distributed species C. suturalis. This is in agreement with previous morphological studies (e.g. Jiroux 2016). Results from this work can be found in Muñoz-Ramírez (2015).



Testing mimicry 

    Despite of being a group with high geographic diversity and multiple geographic color types, co-existing species seem to covariate in their coloration. There are a number of localities were different species (often up to 3) have very similar colors. For example, in the Nahuelbuta National Park (Region de la Araucania), the three species that can be found (C. chilensis, C. buqueti, and C. magellanicus) are all of a red tone. A few kilometers to the East, in the south slope of the Villarrica Volcano, these same three species are green.  There are other places, however, where species show lower color mismatch. In Neltume, for example, two species are typically blue (C. chilensis and C. magellanicus), but a third species (C. buqueti) is green. Another example comes from Tirua, where two species (C. magellanicus and C. buqueti) are almost black, whereas the remaining C. chilensis is reddish. 

Ceroglossus from a single locality in Chiloe Island.
    


A potential mechanism that could explain  color similarity between coexisting species is mimicry, and it has been known for more than a century in Neotropical butterflies. However, in the case of these ground beetles, the pattern seems to be messy enough to rule out an alternative, more simple explanation. What if this pattern arose just by chance?


Ceroglossus from the "Parque Nacional Nahuelbuta",
South-Central Chile. Here, all Ceroglossus species are red.

   
 In order to test for this possibility, I used color data collected with a spectophotometer (thanks to collaborators Pierre-Paul Bitton, and Dr. Stephanie Doucet, University of Windsor, Canada) and a phylogenetic tree that included several subspecies. Then, I compared interspecific color distances to test whether species are more similar when compared within versus between localities. The results showed that species are indeed more similar when in sympatry and that it is very unlikely to obtain such similarity just by chance providing good preliminary evidence for the hypothesis of mimicry.

This study (available here) was featured in the journal's cover (Sept. 2016's issue). You can also find a brief press coverage here, from the Dept. of Ecology and Evolutionary Biology (University of Michigan)'s webpage.


Color divergence and Genetic differentiation

Mimicry (and aposematism) could have additional consequences for biodiversity if color differentiation between different aposematic morphs has an effect on gene flow. Understanding this aspect of mimicry is one of my next goals and the Ceroglossus system provides a particularly good opportunity to test these ideas. I have to thank the support of an NSF doctoral research grant (DEB 16-01260) that is funding this investigation. You can read more about this project in this press note from the Ecology and Evolutionary Biology department (U. of Michigan)'s webpage (link) and from the NSF portal here



Past Projects

Fish phylogeography

As a master student I got involved in the study of a fascinating group of freshwater fish, the family Diplomystidae, thanks to both Dr. Pedro Victoriano and Dr. Evelyn Habit that allowed me to join their labs and conduct research under their tutoring. Several field trips and genetic studies have allowed me to gain a broader knowledge on the evolutionary history of this ancient catfish lineage.

We learnt that there is a higher lineage diversity in the west side of the Andes than in the east, even though the same numbers of endemic species (3) have been described at each side of the Andes. Furthermore, major molecular lineages do not match taxonomic species boundaries (Muñoz-Ramírez et al. 2014). 

In a related project, we also learnt that irrigation canals might be (dangerously) facilitating fish dispersal between historically isolated river basins from Central Chile, which could bring negative impacts to the conservation of aquatic species more generally. We found evidence for this hypothesis by conducting model-based demographic inferences in an approximate Bayesian computation framework (Muñoz-Ramírez et al. 2015). 


network

Haplotype network for populations from the Rapel and
Mataquito basins. Note the lack of genealogical structure.


Teno-Chimbarongo canal
The Teno-Chimbarongo canal artificially connects historically
isolated basins in Central Chile. Image from Muñoz-Ramírez et al. 2015.


We have also determined that the endangered species Diplomystes camposensis has very low genetic diversity in some rives of South Chile (Muñoz-Ramírez et al. 2016). This can affect the evolutionary potential of the species in case the environment changes. It also suggest the possibility that the species may face additional problems if its distribution is fragmented (dams are being built in the rivers where the species lives). Such problems can potentially reduce gene flow between populations, increase homozigosity, and accelerate extinction.  

Diplomystes camposensis, Valdivia Basin. 
Photographied by the Habit's Lab, EULA, UDEC.


Paleontology of the Quiriquina Formation

My first studies were related with the description of fossils from a Cretaceous outcrop in Central Chile, specifically in Concepcion and nearby. Some of the material described include shark and ray teeth (Muñoz et al. 2007), and a gastropod operculum from the family Turbinidae (Muñoz-Ramirez and Moyano 2006). I conducted these research under the supervision of Professors Sylvia Palma-Heldt (UdeC) and Hugo Moyano (UdeC). 

 
Fossils from the Quiriquina Formation 
(Upper Cretaceous), Chile.


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