It's a girl: Atlantic mystery squid undergoes scrutiny.

Three weeks ago, while working the waters south of Key West, Fla., a chartered fishing boat hauled in a surprise: the fresh carcass of a huge squid unlike anything that the people on the boat had ever seen. In fact, according to marine biologists, the gelatinous creature is unlike any known in the Atlantic Ocean.

The fishing boat's captain sent the squid's decomposing body to the Mote Marine Laboratory, headquartered in Sarasota, Fla., where cephalopod specialist Debra A. Ingrao has been studying it. When the specimen arrived on Feb. 22, Ingrao promptly sampled its DNA, fixed the carcass with preservatives, and then began a preliminary dissection. She's sent photographs taken at every step to large-squid experts around the world.

"Most squid are 2 feet long or less," Ingrao notes. Remains from this one, sporting all eight arms, measured more than 6 feet. And that was after a fin of indeterminate length had been chewed off one end of its body.

Gone, too, were all but stubs of the animal's two delicate tentacles. The tentacles, which begin at the base of the arms, tend to be around 7 to 12 times as long as a large squid's mantle, the body part containing I most of the organs.

Ingrao told Science News in an interview at Mote that her "rough guesstimate" for this creature's intact length is 16 to 24 feet. The tentacles were unusually thin and delicate, Ingrao adds.

Last week, after viewing photos of the dissection, Michael Veechione of the Smithsonian Institution in Washington, D.C., identified glands that secrete a gel that holds new eggs. Therefore, the specimen is female, he told Ingrao.

The glands' large size suggests that this female was at or near sexual maturity, says Richard E. Young of the University of Hawaii in Honolulu.

Identification of the species "remains quite tentative," Ingrao notes, although "all information points toward it being Asperoteuthis acanthoderma."

Young notes that "probably fewer than 10" specimens of that species have ever been reported, and all were in the Pacific or Indian Oceans. Confirming A. acanthoderma off Florida would be "a huge range extension--into another ocean" he observes.

"With animals this rare, every new find tells you a little more" says Martin Collins of the British Antarctic Survey in Cambridge, England. For instance, macerated slop in the specimens stomach might identify prey. Furthermore, biologists might estimate the animal's age by counting daily-growth tings in certain bones in the head.

Although muscular squid zip around to catch food, squid with gelatinous bodies typically float in deep, dark waters and let prey find them, Young says. Pacific A. acanthoderma have glowing, prey-alluring pads at the end of their tentacles. Sucker-laden tips on the pads' ends grab curious prey and hold on until the squid moves in to swallow the food.

At least "that's what we think happens," Young says. "No one has yet seen one of these animals alive."

Indeed, most of Young's speculation about A. acanthoderma behavior comes from poring over some 15 specimens of a smaller Asperoteuthis species. His team will soon publish a report describing and naming that species, which is native to Hawaiian waters.