Icthyophaga (often misspelled as Ichthyophaga) is a genus of six species of eagles, closely related to the sea eagles in the genus Haliaeetus. In fact, some taxonomic authorities place this genus within Haliaeetus. Both are native to southeastern Asia, from the Indian subcontinent southeast to Sulawesi. They are smaller than the Haliaeetus eagles, though overlapping in size with the smaller species of that genus. They share similar plumage, with grey heads grading into dull grey-brown wings and bodies, and white belly and legs. They differ in tail colour, with the lesser fish eagle having a brown tail, and the grey-headed fish eagle having a white tail with a black terminal band, and also in size, with the lesser fish eagle only about half of the weight of the grey-headed fish eagle.[1]
In 2005, a molecular systematic study based on nuclear and mitochondrial genes merged this genus into Haliaeetus.[6] In the same year, Ronald Sluys [de] and Masaharu Kawakatsu proposed a replacement of Ichthyophaga with Piscinquilinus,[7] eliminating the controversial name for both birds and worms. A new family, Piscinquilinidae, has been proposed in 2017 to accommodate Piscinquilinus.[8] However, Ernest Williams and Lucy Bunkley-Williams opposed this proposal and advocated retaining the original name for the turbellarian genus Ichthyophaga.[3]
In 2023, based on latest molecular systematic studies, the International Ornithologists' Union resurrected Icthyophaga with its right name and transferred four species from Haliaeetus to this genus.[10] Therefore, this genus now includes the following six species:
As both the common and generic names suggest, both fish eagle and the grey-headed fish eagle feed largely on fish, caught mainly in fresh water on lakes and large rivers, but also occasionally in salt water in estuaries and along coasts.[1]
References
^ abdel Hoyo, J., Elliott, A., & Sargatal, J., eds. (1994). Handbook of the Birds of the World Vol. 2. Lynx Edicions, Barcelona ISBN84-87334-15-6.
^Lesson, RP (1843). "Index ornithologique". L'Écho du monde savant et l'Hermès: Journal analytique des nouvelles et des cours scientifiques. Année 10, Tome 5 (Semestre 1): columns 13–15 (page 6) [in French].
^ abcWilliams, Ernest H.; Lucy Bunkley-Williams (1 August 2017). "An unnecessary replacement name for Ichthyophaga Syromiatnikova 1949 (Platyhelminthes: Prolecithophora) under Article 56.2; and an unnecessary emendation under Article 33.2.3 and the correct spelling of Icthyophaga Lesson 1843 (Aves: Accipitridae)". The Bulletin of Zoological Nomenclature. 74 (1): 136–137. doi:10.21805/bzn.v74.a037. S2CID90690137.
^del Hoyo, J.; Elliott, A.; Sargatal, J. (1994). Handbook of the Birds of the World Vol. 2. Barcelona: Lynx Edicions. ISBN84-87334-15-6.
^Syromiatnikova, I.P. (1949). "A new turbellarian parasitic in fish and called Ichthyophaga subcutanea". Dokl Akad Nauk SSSR. 68: 805–808 (in Russian).
^Laumer, Christopher E.; Giribet, Gonzalo (2017). "Phylogenetic relationships within Adiaphanida (phylum Platyhelminthes) and the status of the crustacean-parasitic genus Genostoma". Invertebrate Biology. 136 (2): 184–198. doi:10.1111/ivb.12169. ISSN1077-8306.
^ICZN (2017). "Closure of Cases (2127, 3543, 3603, 3721, 3726, 3729, 3738, 3741)". Bulletin of Zoological Nomenclature: 142–143.