A zoo in Yokohama city unveiled on Monday a female monkey of a species listed as endangered and dubbed the ''world's most beautiful monkey,'' on lease from the Singapore Zoo. The arrival of the 5-year-old female red-shanked douc langur at Yokohama's municipal zoo, Zoorasia, has spurred hopes for much-awaited babies as the zoo has kept two males of the species since its opening in 1999. ''She's outgoing and had a baby last year. We're hoping she'll pair up with one of the males we have here,'' said Yoshiya Kawaguchi, a breeding staff member at the zoo. Zoorasia has been looking for a female, but it had to wait until now as international trading of monkeys has been restricted due to possible infectious diseases. The red-shanked douc langur inhabits tropical rain forests in Vietnam, Cambodia and Laos. It is designated as an endangered animal on the International Union for Conservation of Nature's Red List after its habitat became extinct due to forest loss caused by chemical defoliants by U.S. forces during the Vietnam War as well as by industrial development.