Eduardo Hajdu

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Eduardo Hajdu

The research team at the Porifera Taxonomy Lab (TAXPO) of Museu Nacional/UFRJ has been focusing its studies on the biodiversity inventory of the Atlantic and the Pacific sides of South America, with the main goal of mapping sponge distributions as accurately as possible, as a subsidy for complementary research programs. Given the mismatch between species distributions and political borders, it soon became obvious that no matter how large Brazil’s coastline might look to some, a sharp view of marine sponge distributions implied getting to know them abroad too. It was quite unfortunate that so little taxonomic effort had been devoted to the study of Uruguayan, Argentinean, Chilean and Peruvian sponges, because it meant that we needed to consider these areas too, or we would never reach a comprehensive view of sponge diversity in South America.

After over a decade dedicated to this taxonomic inventory, and conscious that much more still needs to be done, our team decided that it was also necessary to seek a complementary inventory of sponge diversity in the Greater Caribbean area. Differently from the rationale above, the main motivation for this new research front was not in the lack of knowledge, but on the suspicion that part of this knowledge might be erroneous. This suspicion was born along the onset of the use of molecular techniques in systematics, and the ever larger alleged unlikelihood of distributions deemed too large, or discontinuous.

Discontinuity for coastal species need not depend solely of wide stretches of deep ocean. It might also derive from whichever source of unsuitable coastal habitat, and a case in point is the vast expanse of South America’s coastline under the influence of the sediment and freshwater plume of the Amazon and Orinoco rivers. For this reason, on every opportunity to visit the Greater Caribbean area, we do not restrict ourselves to doing what we have always done, meaning to search for new species, but we also collect comparative materials, and preserve these so that they are ready to be considered in subsequent molecular studies. Such has been the case in Curaçao and Panamá, with smaller collections gathered at Belize, Florida and Martinica.

The last reinforcement in our efforts to verify the status of Caribbean species allegedly occurring in Brazil has been the expedition to Alacranes (southern Gulf of Mexico), when several supposedly well-known species were sampled. These were chosen on the basis of recent results from collecting expeditions along Brazil, and some are already entering ongoing comparative studies by many Brazilian graduate students. The opportunity to be in the field with as rich a group of scientists and students as the reef was rich in marine species, was unique because findings were immediately shared, and integrated in the greater picture. In this way, one was not only looking at how curious a particular species might look like, but given the assemblage of findings of the many specialists, at how curious that particular ecosystem, or habitat might look.

Eduardo Hajdu in ResearchGate

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