Linnaeus took this name from Marcgrave, Edwards and Brisson.
Marcgrave (1648
https://biodiversitylibrary.org/page/43153490 ) spelled it
Iacana in a text that was indeed Latin, without cedillas -- so this is probably where the cedilla got lost. He attributed the word to the Brazilians ('
Brasiliensibus'), and used it as an apparent generic name for 'water hens' ('
gallina aquatica, Waterhun', with the last word printed in Gothic and presumably intended to be German or Dutch). He described four 'species' of this group : the first one was quite clearly the American Purple Gallinule (i.a.: white undertail, a rotund area of turquoise-coloured naked skin on the head, the neck and breast of the colour of the neck of peafowl, yellow legs, no wing spurs [the presence of spurs is listed under the next species as a difference between this and the first species]); the other three all had spurs on the wings, thus (in Brazil and assuming none was a lapwing) were presumably all Wattled Jacanas of different ages/plumages.
Brisson (1760
https://biodiversitylibrary.org/page/36294403 ) presumably adopted the term from Marcgrave, merely turning the initial
I into a
J. Brisson is deemed to have introduced
Jacana as a generic name, before Linnaeus used it as a species-group name. In this genus, he listed what were basically Marcgrave's four species, naming them (French / Latin):
- Le Jacana /
Jacana (= Marcgrave's first species, now
Porphyrio martinicus (Linnaeus 1766) -- so much for this being the type-species of Brisson's genus "by tautonymy" -- e.g.
https://biodiversitylibrary.org/page/14483041 )
- Le Jacana armé ou le Chiriugien /
Jacana armata
- Le Chirurgien noir /
Jacana armata nigra
- Le Chirurgien brun /
Jacana armata fusca
...to which he added a fifth species:
- Le Chirurgien varié /
Jacana armata varia
...which was based on a plate by Edwards (1743, #58, "The Spur-winged Water Hen"
https://biodiversitylibrary.org/page/50240691 ), named by Linnaeus
Fulica spinosa in 1758 (
https://biodiversitylibrary.org/page/727059 ).
Edwards (1764
https://biodiversitylibrary.org/page/50176674 ) published texts that were bilingual English and French, but he did not use
Jacana as an English or French word. He used it only once, in a table at the end of the last part of his work where he added (non-binominal) Latin names to the species he had described in the main text.
Jacana armata nigra et rubra was the Latin name given to his plate #357 (
https://biodiversitylibrary.org/page/50176647 ), in English "The spur-winged Water-hen of Brasil", in French "Le Chirurgien du Bresil".
Then came Linnaeus 1766, who used
jacana as a species-group name (for, i.a., Marcgrave's / Brisson's
fourth species and Edward's plate #357).
Ii have not seen Jacana used as an English word before that point.