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Fish fight breaks out over tiny catch
One small fish: Paedocypris progenetica gets lost on a fingertip.© Maurice Kottelat Cornol Switzerland and Raffles Museum Singapore
You might be more used to arguments about who has caught the biggest fish. But this week a squabble has broken out among zoologists, each of whom is claiming to have found the smallest.
The debate began when Ralf Britz,[link widoczny dla zalogowanych], of London's Natural History Museum, and his colleagues announced the discovery of Paedocypris progenetica,[link widoczny dla zalogowanych], a fish that lives in acidic peat swamps of southeast Asia. With females measuring just 7.9 millimetres long,[link widoczny dla zalogowanych], and males just a tad bigger, the species is truly a tiddler. The researchers claimed it should be recognized as the smallest backboned animal in the world1 (see Go fish!).
not just millimetres that count - it's how you use those millimetres. Ted Pietsch, of the University of Washington in Seattle, points out that last year he described an even smaller fish, which he claims should be recognized as first (or perhaps last) in the size stakes.
"When I saw the paper I thought 'hey!'," Pietsch recalls. He was surprised to see that the researchers made no mention of the deep-sea anglerfish Photocorynus spiniceps, males of which are just 6.2 millimetres long.
My fish is smaller than your fish Pietsch discovered his fish, which lives in waters off the Philippines,[link widoczny dla zalogowanych], by trawling through a museum collection. He described the species at a meeting in Taiwan in May 2005, and later published the details2.
So is his the true king of the mini fish? Like all the best arguments, it's not that simple. Photocorynus spiniceps females are much larger,[link widoczny dla zalogowanych], and the tiny males hitch a ride on their backs as permanent breeding partners. Pietsch/University of Washington
That argument holds no water for Pietsch,[link widoczny dla zalogowanych], however. "To me it doesn't matter if it's a breeding parasite," he says. It is still a sexually mature adult with a backbone, he argues.
Britz counters that because the male's jaws are latched on to the female,[link widoczny dla zalogowanych], it may in fact be longer than Pietsch's measurement. "Salamanders are the smallest vertebrates - there's not even any question,[link widoczny dla zalogowanych]," says David Wake of the University of California,[link widoczny dla zalogowanych], Berkeley.
These amphibians are typically at least several centimetres long. But that is tiny in relation to the size of their genome, Wake points out. Of the 500 different salamander species,[link widoczny dla zalogowanych], many have well over ten times as much genetic material in each cell as humans do. This makes for big,[link widoczny dla zalogowanych], cumbersome cells,[link widoczny dla zalogowanych], which means that adopting a complex body form is more of an achievement given the same body size,[link widoczny dla zalogowanych], Wake argues.
"I'm always surprised that biologists who want to make sophisticated arguments resort to using a metre stick,[link widoczny dla zalogowanych]," he says. "It's not just millimetres that count - it's how you use those millimetres."
Fella feeling
But how should one resolve the fish dispute? Wake suggests judging on the basis of the larger of the two sexes rather than the smaller, meaning that P. progenetica, championed by Britz's team,[link widoczny dla zalogowanych], would emerge victorious.
Either way, it does not look as if either of the camps will hold a grudge against the other. "These are fellas I've known for 30 years," says Pietsch. "It's a very friendly debate."相关的主题文章：

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