"Ironically, we were aided in our search by some of the same people who are now hunting these animals using poisoned darts," Glander said. "It is clear that these animals have only a very limited amount of time before they are hunted out in this area."
The urgency of the rescue mission was intensified when Glander and his colleagues closely examined the captured animals after they had been transported to the Ivoloina Zoological Park in Madagascar, where they will be acclimatized to captivity over the next six months to a year.
"We were struck by the fact that these animals' fur was more uniformly darker than Romeo's, and without the orange that is characteristic of his species, propithecus diadema diadema," said Glander. "The newly rescued animals also have distinctive white 'eyeglasses' of fur encircling their eyes, and their faces are shaped differently."
The primatologists realized they might have discovered a new subspecies of sifaka that is between Romeo's subspecies and a subspecies known to be nearly completely black propithecus diadema edwardsi.
Such a phenomenon of an intermediate subspecies is possible, theorizes Glander, because Romeo's subspecies is found north of the Munubu River, a major river in Madagascar, while the darker propithecus diadema edwardsi subspecies is found quite far south of the river. The new animals were captured just south of the Munubu.
"If genetic testing reveals that the two animals do indeed represent a subspecies unknown to science, it would be a profound tragedy if they were lost," said Glander, who does plan another expedition to the area next year.
Romeo first came to the Primate Center in the fall of 1993 and has awaited a mate there ever since. He has now reached a weight of 14 pounds, well on his way to his adult weight of 18 to 20 pounds.