Although it was true enough, as he had told the Bowmans, that lizard bites were common, Guitierrez had never heard of a basilisk lizard biting anyone. And he had certainly never heard of anyone being hospitalized for a lizard bite. Then, too, the bite radius on Tina's arm appeared slightly too large for a basilisk. When he got back to the Carara station, he had checked the small research library there, but found no reference to basilisk lizard bites. Next he checked International BioSciences Services, a computer database in America, But he found no references to basilisk bites, or hospitalization for lizard bites.

He then called the medical officer in Amaloya, who confirmed that a nine-day-old infant, sleeping in its crib, had been bitten on the foot by an animal the grandmother-the only person actually to see it-claimed was a lizard. Subsequently the foot had become swollen and the infant had nearly died. The grandmother described the lizard as green with brown stripes. It had bitten the child several times before the woman frightened it away.

"Strange," Guitierrez had said.

"No, like all the others," the medical officer replied, adding that he had heard of other biting incidents: A child in Vasquez, the next village up the coast, had been bitten while sleeping. And another in Puerta Sotrero. All these incidents had occurred in the last two months. All had involved sleeping children and infants.

Such a new and distinctive pattern led Guitierrez to suspect the presence of a previously unknown species of lizard. This was particularly likely to happen in Costa Rica. Only seventy-five miles wide at its narrowest point, the country was smaller than the state of Maine. Yet, within its limited space, Costa Rica had a remarkable diversity of biological habitats: seacoasts on both the Atlantic and the Pacific; four separate mountain ranges, including twelve-thousand-foot peaks and active volcanoes; rain forests, cloud forests, temperate zones, swampy marshes, and arid deserts. Such ecological diversity sustained an astonishing diversity of plant and animal life. Costa Rica had three times as many species of birds as all of North America. More than a thousand species of orchids. More than five thousand species of insects.