Corethrura G.R.Gray, 1846 (but see text)
Limnocorax Peters, 1854 (but see text)
Zapornia Leach, 1816 (but see text)
Porzana is a genus of birds in the crake and rail family, Rallidae. Its scientific name is derived from Venetian terms for small rails.[1] The spotted crake (P. porzana) is the type species.
The genus Porzana was erected by the French ornithologist Louis-Pierre Vieillot in 1816 with the spotted crake (Porzana porzana) as the type species.[2] The genus unites the typical "crakes" found essentially anywhere in the world except desert and polar regions. It contains 3 living species. In addition, a large number of prehistorically extinct species known only from fossil or subfossil remains have been discovered. The genera Coturnicops, Crex (including Crecopsis) and Laterallus have been suggested to be closely related.[3]
However, molecular phylogenetic analyses have confirmed the suspicion, raised in the late 20th century in the first cladistic studies of morphology, that the "genus" Porzana is rather an evolutionary grade, consisting of an assemblage of unrelated plesiomorphic rails. Micropygia is maintained as monotypic genus for the ocellated crake until its relationships are fully resolved. The ash-throated crake, which was only tentatively placed in Porzana, has been united with the two former species of Neocrex in Mustelirallus; they are almost certainly closely related to Pardirallus.[3][4][5]
The molecular data find Crex part of a more ancient lineage including Gallirallus and Rallus however; this clade (without Crex) is also well supported by the morphological data, so the similarities between Crex and the crakes seem to be due to a convergent anatomy. Coturnicops and Laterallus, meanwhile, seem closely related to each other and at least the dot-winged crake and yellow-breasted crake as well as Anurolimnas, but not to the core group of Porzana. Part of Amaurornis seems to form a complex with the remaining small species of "Porzana"; the old name Zapornia is now re-established for these. Finally, there is Porzana proper, a group of a few fairly large species which seems close to the last common ancestor of coots and moorhens; the spot-flanked gallinule, presently placed in Gallinula or separated in a monotypic Porphyriops, may be a particularly close relative.[4][5]
These birds are among the smaller members of their family, none being larger than a chicken and some really tiny, smaller than a starling or thrush. Their upperparts are a cryptic lighter or darker brownish hue. The underside is also brown in some, but more often buff or grey. Several species have patterns like whitish dots or black-and-white barred flanks, conspicuous close up, but at a distance providing additional camouflage in these birds' habitat. Some others are rather uniformly blackish-brown all over. The bill and feet are often brightly colored in red to yellow hues; the eyes' iris has some reddish-brownish hue, sometimes being bright red and also very conspicuous at close quarters. Porzana males and females generally differ barely if at all; in the little crake (P. parva), however, they differ so much they might be mistaken for separate species.[6]