{{Short description|Species of fish}} {{Speciesbox | image = Chalceidae Chalceus epakros.jpg | status = LC | status_system = IUCN3.1 | status_ref = <ref name = iucn>{{cite iucn |author=Frederico, R.G. |year=2023 |title=''Chalceus epakros'' |article-number=e.T162748241A162748256 |doi=10.2305/IUCN.UK.2023-1.RLTS.T162748241A162748256.en |access-date=11 August 2025}}</ref> | taxon = Chalceus epakros | authority = Zanata & Toledo-Piza, 2004 }}
'''''Chalceus epakros''''' is a species of freshwater ray-finned fish belonging to the family Chalceidae, the tucan fishes. This fish is found in northern South America. This species was described in 2004, alongside the species ''C. guaporensis'' and ''C. spilogyros''.
== Description == ''Chalceus epakros'' bears visual similarities to other members of the genus ''Chalceus'', like metallic scales and a vivid red or pink caudal fin, though several differences help separate it from its congeners. It has a thin stripe laterally that reaches the caudal peduncle, as well as a longer and more pointed snout.<ref name="ChalceusRevision">{{cite journal|author1=Zanata, A.M. |author2=M. Toledo-Piza |year=2004|title=Taxonomic revision of the South American fish genus Chalceus Cuvier (Teleostei: Ostariophysi: Characiformes) with the description of three new species|journal=Zoological Journal of the Linnean Society|volume=140|issue=11|pages=103–135|doi=10.1111/j.1096-3642.2004.00090.x|doi-access=free}}</ref> It may occasionally bear humeral spots (a spot above each pectoral fin), but they are rather indistinct, especially compared to the humeral spots of ''C. spilogyros''.<ref name="Plazi TreatmentBank" /> Its fins are a mixture of hyaline and reddish-pink, as opposed to the bright-yellow pelvic fins of ''C. erythrurus''.<ref name="FishBase Erythrurus">{{FishBase species|genus=Chalceus|species=erythrurus|month=January|year=2022}}</ref>
''Chalceus erythrurus'' and ''C. macrolepidotus'' may occasionally bear a similar lateral stripe to ''C. epakros'', but theirs are broader and more indistinct.<ref name="Plazi TreatmentBank" /> This is hypothesized to be related to mating habits, and may be more prominent around mating season.<ref name="Alestidae" /> ''C. epakros''<nowiki/>' stripe is composed of chromatophores closer to the surface than that of ''C. erythrurus'' and others.<ref name="ChalceusRevision" />
''Chalceus epakros'' is incredibly visually similar to ''C. guaporensis'', including a thin lateral stripe, a pointed snout, and the occasional indistinct humeral patch.<ref name="Alestidae">Zanata, Angela M. and Vari, Richard P. [https://repository.si.edu/bitstream/handle/10088/896/Zanata-Vari.pdf?sequence=1&isAllowed=y The family Alestidae (Ostariophysi, Characiformes): a phylogenetic analysis of a trans-Atlantic clade]. Zoological Journal of the Linnean Society (2005).</ref> ''C. epakros'' and ''C. guaporensis'' are also alike in that they lack a fontanel (soft, membranous spot) on the head, while the other three species have one between the frontal and parietal bone.<ref name="Alestidae" /> However, ''C. guaporensis'' is slightly larger, and it has 7 pelvic fin rays as opposed to eight on ''C. epakros''.<ref name="Plazi TreatmentBank" /> C. epakros is the smallest ''Chalceus'' species, reaching 17.4 cm TL (with the caudal fin included); ''C. guaporensis'' reaches that same length in SL (without the caudal fin).<ref name="FishBase2">{{FishBase genus|genus=Chalceus|month=December|year=2021}}</ref>
== Etymology == The specific name ''epakros'' is from Greek, and means "pointed at the end", in reference to the longer and more pointed snout;<ref name="ChalceusRevision" /> compare ''Cryptocentrus epakros'', the pointedfin shrimpgoby.
The genus name ''Chalceus'' comes from "chalkos", which is the Greek word for "copper".<ref name="FishBase" /> French biologist Georges Cuvier, who named the first member of ''Chalceus'' (''C. macrolepidotus''), named it this because the preserved specimen's scales were copper-colored ("sometimes golden") when preserved in alcohol, though its scales are silvery in life.<ref name="ETYFish">{{cite web|last1=Scharpf|first1=Christopher|last2=Lazara|first2=Kenneth J.|date=15 September 2020|title=Order CHARACIFORMES: Families IGUANODECTIDAE, TRIPORTHEIDAE, BRYCONIDAE, CHALCEIDAE and GASTEROPELECIDAE|url=https://etyfish.org/characiformes8/|access-date=31 December 2021|website=The ETYFish Project}}</ref><ref name="Original">{{cite journal|last1=Cuvier|first1=Georges|date=1818|title=Sur les Poissons du sous-genre Myletes|url=https://www.biodiversitylibrary.org/page/34812546#page/506/mode/1up|journal=Mémoires du Muséum d'histoire naturelle|volume=4|page=454|access-date=1 January 2022}}</ref>
== Taxonomy == In 2004, Brazilian biologists Mônica Toledo-Piza and Angela M. Zanata performed a re-examination of the genus ''Chalceus'', resulting in the nomination of not only ''C. epakros'' but its congeners ''C. guaporensis'' and ''C. spilogyros''.<ref name="ChalceusRevision" /> Upon study in 2005, ''C. epakros'' and ''C. guaporensis'' were determined to form a clade, accounting for their visual similarities, while ''C. spilogyros'', ''C. erythrurus'', and ''C. macrolepidotus'' share another.<ref name="Alestidae" />
Previously, specimens of ''C. epakros'' had been misidentified as specimens of ''C. macrolepidotus'' and ''C. erythrurus''; ''C. macrolepidotus'' (Cuvier) and ''C. erythrurus'' (Cope) are long-established members of the genus, having been named in 1818 and 1870, respectively.<ref>{{cite journal|last1=Reis|first1=Roberto|last2=Toledo-piza Ragazzo|first2=Monica|last3=Harold|first3=Antony|last4=Pavanelli|first4=Carla|last5=Buckup|first5=Paulo A.|date=2003|title=Genera incertae sedis in Characidae|url=https://www.academia.edu/21340123|access-date=27 December 2021}}</ref>
== Habitat == Like the rest of its genus, ''C. epakros'' is a freshwater fish from northern South America.<ref name="Catalog">{{cite web|last1=Fricke|first1=Ron|last2=Eschmeyer|first2=William N.|date=2020|title=''Chalceus epakros''|url=https://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatget.asp?spid=67830|access-date=27 December 2021|website=Eschmeyer's Catalog of Fishes|publisher=California Academy of Sciences}}</ref> ''C. epakros'' has the widest distribution of all ''Chalceus'' species, inhabiting the Amazon basin, the Orinoco river, and the Essequibo river.<ref name="ChalceusRevision" /><ref name="FishBase">{{FishBase species|genus=Chalceus|species=epakros|month=December|year=2021}}</ref> Despite sharing a clade, ''C. epakros'' and ''C. guaporensis'' are not found in the same areas; this could either be due to competition between the species, or due to slight differences in environmental needs.<ref name="Spatial Relationship">{{Cite journal|last1=Torrente-Vilara|first1=Gislene|last2=Cella-Ribeiro|first2=Ariana|last3=Hauser|first3=Marília|last4=Röpke|first4=Cristhiana|last5=Freitas|first5=Maria Helena|last6=Doria|first6=Carolina Rodrigues da Costa|last7=Zuanon|first7=Jansen|date=10 May 2018|title=Spatial segregation between Chalceus guaporensis and Chalceus epakros (Osteichthyes: Characiformes) in the Madeira River, Amazon Basin|url=http://www.scielo.br/j/aa/a/kj83MPMYh4TnMYKkC8stmFF/?lang=en|journal=Acta Amazonica|language=en|volume=48|issue=3 |pages=239–247|doi=10.1590/1809-4392201703022|s2cid=91368802 |issn=0044-5967|doi-access=free}}</ref>
''Chalceus epakros'' and ''C. macrolepidotus'' are the only two ''Chalceus'' species known to occur in Guyana.<ref name="Plazi TreatmentBank">{{cite web|title=Chalceus, Cuvier, 1817|url=http://treatment.plazi.org/id/623087C7FF9FFFD8FC487AF1FB48FD87|access-date=27 December 2021|website=Plazi TreatmentBank}}</ref>
== Diet and behavior == ''Chalceus epakros'' seems to largely be an insectivore, targeting ants and wasps. In one study (Torrente-Vilara et al.), very few examined specimens had food material in their stomachs, making diet-mapping difficult.<ref name="Spatial Relationship" /> This lines up with other, more thoroughly-studied ''Chalceus'' species, which target similar invertebrate spreads.<ref name="SeriouslyFishErythrurus">{{cite web|title=Chalceus erythrurus (Tucanfish)|url=https://www.seriouslyfish.com/species/chalceus-erythrurus/|access-date=27 December 2021|website=Seriously Fish}}</ref><ref name="FishBaseMacrolepidotus">{{FishBase species|genus=Chalceus|species=macrolepidotus|month=December|year=2021}}</ref>
Behaviorally, ''C. epakros'' is lacking in data. Other members of the genus are active, fast-moving, and somewhat skittish.<ref name="MaidenheadMacrolepidotus">{{cite web|title=Pink-tail Chalceus Species Profile|url=https://www.fishkeeper.co.uk/help-and-advice/freshwater/characins/pink-tail-chalceus|access-date=27 December 2021|publisher=Maidenhead Aquatics}}</ref><ref name="Aqua-Imports">{{cite web|title=Yellowfin Chalceus (Chalceus erythrurus)|url=https://www.aqua-imports.com/product/yellowfin-chalceus-chalceus-erythrurus/|access-date=27 December 2021|website=Aqua-Imports}}</ref>
== References == {{Reflist}}
{{Taxonbar|from=Q5536361}}
Category:Freshwater fish of South America epakros Category:Taxa named by Angela Maria Zanata Category:Fish described in 2004