The jacanas (sometimes referred to as Jesus birds or lily trotters) are a group of tropical waders in the family Jacanidae. They are found in the tropical regions around the world. They are noted for their elongated toes and toenails that allow them to spread out their weight while foraging on floating or semi-emergent aquatic vegetation. They are also among the somewhat rare groups of birds in which females are larger, and several species maintain harems of males in the breeding season with males solely responsible for incubating eggs and taking care of the chicks.
The family Jacanidae was introduced in 1854 by the French naturalists Jean-Charles Chenu and Marc des Murs. They used the spelling "Jacaneinae".[1][2] The modern spelling "Jacanidae" was used by Leonhard Stejneger in 1885.[3]
The pronunciation of the word jacana is debated. Jacana is Linnæus' scientific Latin spelling of the Portuguese jaçanã which in turn is derived from a Tupi name of the bird, ñaha'nã.[4] The Portuguese word is pronounced approximately [ʒɐsɐˈnɐ̃]. As in façade, Provençal, and araçari, the Ç is meant to be pronounced as an S. US dictionaries give various pronunciations: /ˌʒɑːsəˈnɑː/ ZHAH-sə-NAH,[5][6] /ˌdʒɑːsəˈnɑː/ JAH-sə-NAH,[6] as well as the anglicised /dʒəˈkɑːnə/ jə-KAH-nə,[7] which is the only pronunciation in an Australian dictionary.[8] A British dictionary gives /ˈdʒækənə/ JAK-ə-nə for the spelling "jacana" and /ʒæsəˈnɑː/ zhass-ə-NAH for "jaçana".[9]
Eight species of extant jacana are known from six genera and four fossil species have been described from the Oligocene of Egypt [12] and from the Pliocene of Florida.[13] A fossil from Miocene strata in the Czech Republic was assigned to this family,[14] but more recent analysis disputes the placement and moves the species to the Coraciidae.[15]
Jacanas are identifiable by their elongated toes and claws which enable them to walk on floating vegetation in the shallow lakes that are their preferred habitat. They have sharp bills and rounded wings, some with carpal spurs, and many species also have wattles and frontal lappets on their foreheads.[16] Jacanas were once placed in the family Parridae based on the genus Parra but the family name is now Jacanidae based on the type genus Jacana. The family is placed within the order Charadriiformes under the suborder Scolopaci and is a sister of the Rostratulidae. They have 10 tail feathers unlike most others wader groups which have twelve. They have a rudimentary caecum.[17] Most jacanas have five neck vertebrae with the exception of Hydrophasianus chirurgus which has six.[18]