Endangered by Taxonomy

5 January 2010

Taxonomists really are a miserable lot.  Like mall cops and Canadians, they sport inferiority complexes the size of Wales.  Make the mistake of asking one about her work and expect a nauseatingly lengthy lecture on the “relevance” of systematics.

Sometimes though, they have a point.  Classification systems can have real world consequences.  Perhaps no where is this more striking than in cases of conservation efforts for endangered populations of organisms.  There is an implicit assumption that “species” are more worthy of protection than “subspecies.”

Occasionally, one endangered population that constitutes a putative species is sunk into synonymy with another more abundant species, alleviating or at least diminishing what had appeared to be a conservation crisis.  Such was the case Chelonia “agassizii,” the black turtle of the eastern Pacific now considered to be a distinctive (but not specifically distinct) sub-population of the green turtle Chelonia mydas. In some cases there are factions that resist such taxonomic revision on the grounds that it will jeopardize the population — taxa that are distinguished on the basis of conservation concerns have been termed “geopolitical species.”

More often it seems to go the other way though.  One species is split into two or more, often creating endangered species in the process whole cloth when a restricted regional endemic or rare variant is elevated to species status.  Today the BBC is reporting just such a case.  Biologists are beginning to suspect that one threatened species of Amazon fish, the pirarucu (Arapaimagigas“), may in fact be several critically endangered species.

Among the largest freshwater fish in the world pirarucu, belong to an ancient and impressive family of fish, the Osteoglossids.  Aptly named, the group is distinguished by a bony “tongue” covered with toothlike projections that function in feeding.  Like many fish that live in sluggish waters, all members of the family occasionally gulp air and absorb oxygen across a vascularized swim bladder.  Pirarucu are “obligate” air breathers frequently coming to the surface to breathe, one of the factors that makes them easily hunted by Amazonian fishermen.  Apparently they are also delicious.  For some reason they are also quite popular with video game designers. They also appear to like sticking anacondas in trees but that’s a whole other story.

Pirarucu seemingly take to captivity fairly well, and can be seen in many public aquaria including the California Academy of Sciences where I shot the time lapse sequence at top a few days ago.

Hat-tip: Knight Science Journalism Tracker

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