Biology.

A second living-fossil species?

Two research teams have found evidence that the Indonesian coelacanth reported last year is a new species.

One group bases its claim on mitochondrial DNA and morphology. The newly discovered fish is distinct from, but closely related to, the only other known coelacanth, say Laurent Pouyaud of Jakarta's branch of the French Scientific Research Institute for Development and his Indonesian coauthors.

Their formal description of the new species and its name, Latimeria menadoensis, appear in the April COMPTES RENDUS DE L'ACADEMIE DES SCIENCES.

The other research team includes Mark V. Erdmann of the University of California, Berkeley. He had spotted, but not purchased, one of the living fossils in a market on his honeymoon and then chased rumors for months before fishermen brought him another specimen (SN: 9/26/98, p. 196). He later donated the specimen to the Indonesians who worked with Pouyaud. His team's analysis of the fish agrees with that of Pouyaud's group: Genetically, the coelacanth seems to be a new species.

Saying that when he donated the fish he had expected the Indonesians to do any naming, Erdmann protests Pouyaud's publication of a name. "The fish is now Latimeria menadoensis Pouyaud et al.," he laments. Responding for Pouyaud, his colleague Patrice Levang argues that "the Indonesians were the rightful owners of the fish," and they could work with whomever they wished. ---S.M.

Long-sought migration trigger stinks

A molecule in the distinctive perfume of fish could be one of the triggers for a mysterious daily migration in lakes.

Water fleas, among other tiny aquatic creatures, swim to the protective dimness of lower depths during the day. At night, when fish retire, Daphnia hyalina venture back up to warmer water, where growth and reproduction are easier. The triggers for this migration, or for just about any other so-called inducible defense, have long eluded scientists.

The water fleas' cue may include trimethylamine (TMA), an element of fish odor, report Hinnerk Boriss and his colleagues at the Max Planck Institute for Limnology in P16n, Germany. In the April 1 NATURE, they describe water fleas clustering lower in the laboratory tubes holding water with greater concentrations of TMA.

Stanley I. Dodson of the University of Wisconsin-Madison calls the paper "important." Once the molecular alerts are identified, he says, "we will be able to design elegant experiments" on chemical communications in water. --S.M.

Nuptial balloons: Size doesn't matter

The biggest balloon is not the one that gets the girl, at least among dance flies. That's the conclusion of the first analysis of the shiny saliva orbs that the males clutch as courtship gifts, report Jennifer A. Sadowski of the University of Kentucky in Lexington and her colleagues. They describe the nuptial balloons of Empis snoddyi in the March BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY.

Males hold balloons a few millimeters in diameter between their rear legs as they swarm in the early morning. "It's like little points of light," notes coauthor Allen J. Moore of the National Science Foundation in Arlington, Va. The gift presented to the female "looks nice, but there's nothing of value," he says.

Flies of some related species offer nutritious gifts instead. "Females prefer a male with a big dead insect to a male with a small dead insect," Moore explains.

After monitoring wild swarms of dance flies, Sadowski reports that the shiny gifts of E. snoddyi don't follow the pattern of big dead insects. The bigger male may win, but a bigger balloon doesn't help. Moore speculates that too much empty glitter proves unwieldy when males fight. --S.M.