Journal Number 91
June 2004

FISHING ON THE NET

Lumpers and Splitters
A search in Google came up with a few gems, showing we are not alone in our confusion....

"Bird guides used to illustrate a species called the Yellow-shafted Flicker, distributed mainly in Eastern North America, and a very similar Red-shafted Flicker, found in Western North America. The birds are so similar that at first glance they look the same. The main difference is, as the Yellow-shafted flies away, flashes of yellow feathers are seen, but when the Red-shafted flies away, you see, of course, reddish feathers."

"The problem is that in midcontinent, in a small area where the distributions of the birds formerly known as the Yellow-shafted and Red-shafted Flickers overlap, there is a zone where it's not uncommon to spot flickers which flash a colour between yellow and red -- a sort of salmon-colour. The yellow- and red-feathered birds can mate to produce offspring with intermediate characteristics. The sticking point is that part of the definition of `species' is that individuals belonging to one species shouldn't be able to mate easily and produce vigorous, reproducing offspring with individuals belonging to another species."

"Therefore, nowadays experts have `lumped' Yellow-shafted and Red-shafted Flickers into one species, and that one species is known as the Northern Flicker. The two former `species' are now thought of as `races', or `subspecies'."

"Lumping and splitting refer to the rearranging of taxonomic groups of species. The naming of a particular species should be regarded as a hypothesis about the evolutionary relationships and distinguishability of that group of organisms. As further information comes to hand, the hypothesis may be confirmed or refuted. When two named species are discovered to be of the same species, the older species name is usually retained, and the newer species name dropped, a process called synonymization, or convivially, as lumping. Dividing a taxon into multiple, often new, taxon's is called splitting. Taxonomists are often referred to as `lumpers' or 'splitters' by their colleagues, depending on their personal approach ...."

"As one of my professors used to say, there are two basic types of psychologists - lumpers and splitters. The lumpers try to find the universal principles that apply to all people. The splitters like to focus on differences between people. My guess is that a balance of both approaches is the best way to go."

"Unfortunately, I think that ego often plays way too much a part in both lumping and splitting.
It is easy to let your ego motivate you when writing a paper. It sure would be nice if there was one clear set of rules and everybody followed them. I'm not holding my breath."

"I am way sick of specimens being split apart, renamed, placed in different genera and families, etc. Splitters tend to forget, or WANT to forget, that SOME species can be so closely related that they belong in the same genus. And we damn well know that more than one species of dinosaur belonged in each genus, and I am sure we have found some of them. We should lump when necessary, and split when necessary. When anatomical details are minor, distinct species are closely related, and geological separation (by locale and time period) are minor, sometimes it is reasonable to lump.

I am a lumper at heart... I favour the lumping of all species of Corythosaurus, Lambeosaurus, and Hypacrosaurus into Hypacrosaurus - quite a reasonable lumping. I think that until more fossils are discovered, Ultrasauros should be placed in Brachiosaurus. Struthiomimus and Ornithomimus, I believe, should be united. Ditto Gryposaurus, Hadrosaurus, and Kritosaurus. And, for some reason, Orodromeus looks suspiciously similar to Hypsilophodon...."