Black-winged hatchetfish: Not one, but three species

[mewickham]

It turns out that the black-winged hatchetfish (Carnegiella marthae) is actually three very similar species: http://www.practicalfishkeeping.co.uk/content.php?sid=3603

[etheonut]

Splitters at work, molecular genetics is an amazing thing.

I saw a similar article yesterday where they examined 3 species of blenny and when all was said and done they had 10 species.

Kevin

[sumpnfishy]

Kevin is a long time Lumphead, oops, I mean lumper.
After reading the report I really have to wonder about how much genetic difference they are talking about. The only external differences they talk about are in bodily markings which can not be used to differentiate species. If they could then there would be people trying to separate yellow head and blue head Cyprichromis that school and breed together in Tanganyika into different species.
When Kevin and I helped a couple of guys from Nebraska do some collecting for research on Plains topminnows they sent us their DNA findings that showed greater genetic variation between streams a couple miles apart in Missouri than they found in the entire Platte River system in Nebraska. Some splitters would use that to argue a species complex but you would find no anatomical differences whatsoever.
Michael

[etheonut]

I am not saying that there isn't room for these kinds of studies. My problem is that they only get any fanfare if they find new species. That breeds extreme bias into these studies. Bias in science only leads to bad science.

Kevin

[mewickham]

Yeah, DNA evidence isn't always dependable. Didn't two different studies of discus recently arrive at differences in the numbers of discus species? The tests were made on different segments of DNA. Or was one nucleic DNA and the other mitochondrial? I forget. Anyway, testing a particular segment might say two organisms are of the same species, but testing some other segment could give opposite results. My understanding is that DNA testing is expensive, so the studies typically only study tiny snippets of the code-- not the whole genome.

Of course, in this case of hatchetfish, they also found differing numbers of fin rays and teeth to back up the results.

And Kevin is right. Fanfare can bias the research. Just look at the global warming field.