Hydrolycus

{{Short description|Genus of fishes}} {{Automatic taxobox | image = Hydrolycus scomberoides by OpenCage.jpg | image_caption = ''Hydrolycus scomberoides'' | taxon = Hydrolycus | authority = (J. P. Müller & Troschel, 1844) | type_species = Hydrocyon scomberoides | type_species_authority = Cuvier, 1819<ref name = "Cof family">{{Cof family|family=Cynodontidae|access-date=17 July 2025}}</ref> }}

'''''Hydrolycus''''' is a genus of freshwater ray-finned fishes belonging to the family Cynodontidae, the dogtooth characins. These fishes are found in tropical South America, where found in the Amazon and Orinoco basins, as well as rivers of the Guianas.<ref name=fishbase>{{FishBase genus | genus = Hydrolycus| month = January | year = 2017}}</ref> The genus includes the largest dogtooth characins, reaching up to {{convert|1.17|m|ft|abbr=on}} in length.<ref name=fishbase/> They have long, pointed teeth (shorter and less extreme in ''H. wallacei'') used for spearing their prey, generally smaller fish.<ref name=Toledo1999>{{cite journal |author1=Toledo-Piza, M. |author2=N.A. Menezes |author3=G.M. Santos | year=1999 | title=Revision of the Neotropical fish genus Hydrolycus (Ostariophysi: Characiformes: Cynodontidae) with the description of two new species | journal=Ichthyol. Explor. Freshwaters | volume=10 | issue=3 | pages=255–280 }}</ref> In a study of the stomachs of 45 individuals, most were empty, but among the remaining the prey fish were 15–50% of the length ''Hydrolycus'' itself.<ref name=Goulding1980>{{cite book | author=Goulding, M | year=1980 | title=The Fishes and the Forest: Explorations in Amazonian Natural History | publisher=University of California Press | pages=185–186 | isbn=0-520-04131-3 }}</ref>

In 1999 two new species were described, the first in this genus in 158 years.<ref name=fishbase/><ref name=Toledo1999/>

==Species== [[File:Hydrolycus armatus cropped.jpg|thumb|''Hydrolycus armatus'']]

There are currently four described species.<ref name="Cof genus">{{Cof genus|genus=Hydrolycus|access-date=17 July 2025}}</ref>

* ''Hydrolycus armatus'' (Jardine, 1841) (Payara) * ''Hydrolycus scomberoides'' (G. Cuvier, 1819) (Payara) * ''Hydrolycus tatauaia'' Toledo-Piza, Menezes & dos Santos, 1999 * ''Hydrolycus wallacei'' Toledo-Piza, Menezes & dos Santos, 1999

==References== {{Reflist}}

Category:Cynodontidae Category:Hydrolycus Category:Taxa named by Johannes Peter Müller Category:Taxa named by Franz Hermann Troschel Category:Freshwater fish of South America