“Time passes better when you ask questions
Robert Silverberg

I am primarily a “taxon-oriented scientist” working on amphibians and reptiles and I like the idea of being a generalist herpetologist. My research interests are thus relatively broad and eclectic, although currently mostly based on the Neotropical herpetofauna. They include, for instance, adaptation to highland habitats, alpha-taxonomy, ancestral reconstruction, bioacoustics, biogeography, conservation, evolution, genetic basis of phenotypic variation, phylogenetics, phylogeography, reproduction strategies, species boundaries, systematics, etc.

I try to spend as much time as possible in the field, first to collect samples for my research projects, but also because I like to understand the natural history of the organisms I am studying (i.e. observing them alive interacting with their environment), not only working with tissue samples, pipettes, sequencing machines and computer programs. Another – I confess major – reason is that I just like to be in the field, camping in my tent or hammock and living a simple life surrounded by the wilderness, far from the tumult and craziness of the human world.

 

It may sound old-fashioned nowadays, but I do like describing/re-describing species, even if I am enthused by many other evolutionary questions.
Like many scientists, my life has been greatly influenced by the reading of adventurers’ stories while I was a child, dreaming of exploration and discovery of unknown fabulous animals in untouched places and impressive landscapes. What would be more exciting than being an explorer describing species previously unknown to science? That dream partly became a reality and I feel fortunate to have been able to explore the “fairy worlds” of my childhood and describe some previously unknown taxa.
Delimiting species (the extant earth’s biodiversity) is a core problem in biology, not to say a philosophical debate, but is highly necessary not only for conservation purposes, but also in order to understand evolutionary mechanisms. Although there is a tendency to trivialize it, the process of describing taxa is far less simple than some people state (usually people who do not describe species). If the descriptive part can be achieved by anyone having basic skills in morphology, deciding when to recognize a species as new and finding valid qualitative diagnostic characters are often a challenge.
We have to admit that morphology alone can sometimes be strongly misleading, therefore an integrative approach is becoming increasingly popular (the so-called “integrative taxonomy”). Replacing field clothes with lab clothes and sequencing DNA fragments to compare species/populations in a phylogenetic perspective is very helpful (not to say necessary in some difficult groups), and opens many new doors that are occasionally almost equally exciting as being in the field.

Some new taxa described

  
  
  
  
  
  

“The Lost World”

Since 2007 my main research project focus on the tepui ecosystem in northern South America where I am trying to disentangle the processes behind the evolution of organisms in these “islands in the sky”. I am also working on phylogenies and taxonomic revisions of several taxa inhabiting this outstanding area.

 

The tepuis are the impressive abrupt-sided table mountains that arise above the savannah and tropical forest mainly in southern Venezuela, west-central Guyana, and Brazil. The iconic, unreachable and mysterious table mountains can reach 3km elevation and have up to 1000m vertical cliffs. These behemoths, most having been visited less than the moon, are erosional remnants of extremely old (Precambrian) sandstone sediments that were uplifted and subsequently eroded by tectonic forces, wind and weathering during millions of years.

 

In 1912, Sir Arthur Conan Doyle, largely inspired by the tepui geomorphology [and by the account of an expedition of the Royal Geographical Society of London on the summit of Mount Roraima (led in 1884 by Sir Everard im Thurn)], published one of his most famous novels “The Lost World”, which stirred numerous fiction movies. In Doyle’s novel a tepui summit harbours dinosaurs and a forgotten civilisation living isolated for millions of years. Because of their age and isolation, scientists have long believed – like Conan Doyle – that the table mountains mostly harbour old endemic lineages, some possibly contemporary to the dinosaurs and predating the separation of Africa and South America. Actually, Doyle book’s topic remains an evolutionary enigma: how and when did the tepuis summit fauna diversify?

My co-workers (Ross D. MacCulloch, D. Bruce Means, Kim Roelants, Ines Van BocxlaerFranky Bossuyt) and I recently partly solved this enigma, and our results not only contradict the traditional view of relict tepui lineages living in long isolation, but could also challenge the age of the dissection in individual tepuis, which until now was generally supposed to date back to the Cretaceous (70 to 100 million years ago), when dinosaurs still roamed the earth. Studying the DNA of numerous specimens belonging to six groups of amphibians and reptiles from 17 tepuis/tepui massifs, my collaborators and I found that instead of being old and distantly related, most tepui tops populations are “young” and closely related to each other or to populations from the surrounding uplands. This sharply contrasts with the many recent discoveries of huge cryptic diversity in other regions that have much less dramatic landscapes. Interestingly, even species or populations living in very specific habitats found only on the highest and most isolated tepui summits (thus not in the intervening uplands) are often unexpectedly closely related. Because amphibians and reptiles (especially those ecologically specialized taxa) likely have limited dispersal abilities, this observation questions the exact age of fragmentation of some currently isolated tepuis, which could be more recent than usually supposed. Estimation of divergence time indicates that many summit populations were in contact as recent as during the late Pleistocene-Holocene (less than 1.8 million years ago), thus challenging the “Lost World” romantic preconception that probably biased scientists’ mind for many years. Check my paper in Current Biology for more information [pdf].

Since that publication we expanded our dataset and now have gathered information from 21 tepui summits in the Eastern Pantepui District, which is probably the largest dataset ever compiled in the area (at least for vertebrates).
Getting closer to completely unlock the secrets of the “Lost World”!