Serrasalmidae

{{Short description|Family of fishes}} {{Automatic taxobox | fossil_range = {{fossil range|38|0|earliest=66|Late Eocene to present}} Possible Maastrichtian occurrence | image = Piranha-serrasalmus manueli 01.jpg | image_caption = ''Serrasalmus manueli'' | taxon = Serrasalmidae | authority = Bleeker, 1859<ref name = VDLEF>{{cite journal | author1 = Richard van der Laan | author2 = William N. Eschmeyer | author3 = Ronald Fricke | name-list-style = amp |year=2014 | title = Family-group names of recent fishes | url = https://biotaxa.org/Zootaxa/article/view/zootaxa.3882.1.1/10480 | journal = Zootaxa | volume = 3882 | issue = 2 | pages = 1–230| doi = 10.11646/zootaxa.3882.1.1 | pmid = 25543675 | doi-access = free }}</ref> | type_genus = ''Serrasalmus''<ref name = VDLEF/> | type_genus_authority = Lacepède, 1803<ref name = "Cof family">{{Cof family|family=Serrasalmidae|access-date=25 June 2025}}</ref> | subdivision_ranks = Genera | subdivision_ref = <ref>{{FishBase family | family = Serrasalmidae| month = April | year = 2013}}</ref> | subdivision = See text }}

The '''Serrasalmidae''' (serrasalmids) are a family of characiform fishes native to freshwater habitats of South America. They include more than 90 species. The name means "serrated salmon family", which refers to the serrated keel running along the belly of these fish. Fish classified as Serrasalmidae are also known by these common names: '''pacu''', '''piranha''', and '''silver dollar'''. These common names generally designate differing dental characteristics and feeding habits.<ref name="opefeserra">{{cite web |last=Magallanes |first=Frank |date=2006-04-06 |title=Subfamily Serrasalminae |url=http://www.opefe.com/serrasalminae.html |publisher=Oregon Piranha Exotic Fish Exhibit |format=Website}}</ref>

==Description== Serrasalmids are medium- to large-sized characiform bony fishes that reach about {{convert|1|m|ft|abbr=on}} long, generally characterized by a deep, laterally compressed body with a series of midventral abdominal spines or scutes, and a long dorsal fin (over 16 rays). Most species also possess an anteriorly directed spine just before the dorsal fin extending from a supraneural bone; exceptions include members of the genera ''Colossoma'', ''Piaractus'', and ''Mylossoma''.<ref name="Freeman3">{{harvnb|Freeman|Nico|Osentoski|Jelks|2007|p=3}}</ref>

Most serrasalmids have about 60 chromosomes, ranging from 54 to 62. ''Metynnis'' has 62 chromosomes, as does ''Catoprion'', ''Pristobrycon striolatus'', and ''Pygopristis''.<ref name="Freeman6"/>

== Evolution ==

=== Taxonomy === The Serrasalmidae were until, recently, classified as a subfamily of the Characidae, with their taxonomic relationships uncertain at the time.<ref name="Freeman2">{{cite journal |last1=Freeman |first1=Barbie |last2=Nico |first2=Leo G. |last3=Osentoski |first3=Matthew |last4=Jelks |first4=Howard L. |last5=Collins |first5=Timothy M. |year=2007 |title=Molecular systematics of Serrasalmidae: Deciphering the identities of piranha species and unraveling their evolutionary histories |url=http://www.mapress.com/zootaxa/2007f/zt01484p038.pdf |journal=Zootaxa |volume=1484 |page=2 |doi=10.11646/zootaxa.1484.1.1 |bibcode=2007Zoot.1484....1F |access-date=2009-06-25 |doi-access=free}}</ref> More recent studies have found them to belong to a wider clade of South American characoids, being most closely related to the Hemiodontidae.<ref name=":0">{{Cite journal |last1=Kolmann |first1=M A |last2=Hughes |first2=L C |last3=Hernandez |first3=L P |last4=Arcila |first4=D |last5=Betancur-R |first5=R |last6=Sabaj |first6=M H |last7=López-Fernández |first7=H |last8=Ortí |first8=G |date=2021-05-01 |title=Phylogenomics of Piranhas and Pacus (Serrasalmidae) Uncovers How Dietary Convergence and Parallelism Obfuscate Traditional Morphological Taxonomy |url=https://academic.oup.com/sysbio/article/70/3/576/5891674 |journal=Systematic Biology |volume=70 |issue=3 |pages=576–592 |doi=10.1093/sysbio/syaa065 |pmid=32785670 |issn=1063-5157}}</ref> The Serrasalmidae are relatively well understood, and agreement is wide on the genera and species included.<ref name="Freeman3" />

The family is classified as follows:<ref name=":0" /><ref name=":13">{{Cite web |last1=Fricke |first1=R. |last2=Eschmeyer |first2=W. N. |last3=Van der Laan |first3=R. |date=2025 |title=ESCHMEYER'S CATALOG OF FISHES: CLASSIFICATION |url=https://www.calacademy.org/eschmeyers-catalog-of-fishes-classification |access-date=2025-04-28 |website=California Academy of Sciences |language=en}}</ref><ref name="CofFF">{{Cof family|family=Serrasalmidae|access-date=28 April 2025}}</ref>

* Family '''Serrasalmidae''' Bleeker, 1859 ** Subfamily Colossomatinae Kolmann ''et al.'', 2021 (lowland pacus)<ref name=":1">{{Cite journal |last1=Kolmann |first1=M A |last2=Hughes |first2=L C |last3=Hernandez |first3=L P |last4=Arcila |first4=D |last5=Betancur-R |first5=R |last6=Sabaj |first6=M H |last7=López-Fernández |first7=H |last8=Ortí |first8=G |date=2021-05-01 |title=Phylogenomics of Piranhas and Pacus (Serrasalmidae) Uncovers How Dietary Convergence and Parallelism Obfuscate Traditional Morphological Taxonomy |url=https://academic.oup.com/sysbio/article/70/3/576/5891674 |journal=Systematic Biology |volume=70 |issue=3 |pages=576–592 |doi=10.1093/sysbio/syaa065 |pmid=32785670 |issn=1063-5157}}</ref> *** Genus ''Colossoma'' Eigenmann & Kennedy, 1903 *** Genus ''Mylossoma'' Eigenmann & Kennedy, 1903 *** Genus ''Piaractus'' Eigenmann, 1903 ** Subfamily Myleinae Eigenmann, 1903 (upland pacus) *** Genus ''Acnodon'' Eigenmann, 1903 *** Genus ''Mylesinus'' Valenciennes, 1850 *** Genus ''Myleus'' Müller & Troschel, 1844 *** Genus ''Myloplus'' Gill, 1896 *** Genus ''Ossubtus'' Jégu, 1992 *** Genus ''Paramyloplus'' Norman, 1929 *** Genus ''Prosomyleus'' Géry, 1972 *** Genus ''Tometes'' Valenciennes, 1850 *** Genus ''Utiaritichthys'' Miranda Ribeiro, 1937 ** Subfamily Serrasalminae Bleeker, 1859 (piranhas) *** Genus ''Catoprion'' Müller & Troschel, 1844 *** Genus †''Megapiranha'' Cione ''et al.'' 2009 (fossil; Late Miocene)<ref name="MegaVertpaleo">{{Cite journal |last1=Cione |first1=Alberto Luis |last2=Dahdul |first2=Wasila M. |last3=Lundberg |first3=John G. |last4=Machado-Allison |first4=Antonio |year=2009 |title=''Megapiranha paranensis'', a new genus and species of Serrasalmidae (Characiformes, Teleostei) from the Upper Miocene of Argentina |journal=Journal of Vertebrate Paleontology |volume=29 |issue=2 |page=350 |bibcode=2009JVPal..29..350C |doi=10.1671/039.029.0221 |s2cid=86046546}} ([https://web.archive.org/web/20101111103144/http://www.angelfire.com/biz/piranha038/megapiranha_paranensis.html Summary of the paper]).</ref> *** Genus ''Metynnis'' Cope, 1878 *** Genus ''Pygocentrus'' Müller & Troschel, 1844 *** Genus ''Pygopristis'' Müller & Troschel, 1844 *** Genus ''Serrasalmus'' Lacepède, 1803 (=''Pristobrycon'' Eigenmann, 1915)

=== Fossil record === The fossil record, particularly for piranhas, is relatively sparse. Most known fossils are from the Miocene.<ref name="Freeman6" /> The earliest definitive serrasalmid fossil teeth are known from the Late Eocene-aged (~38 mya) sediments of the Santa Luca Formation in Bolivia.<ref name=":1" /> Teeth resembling those of pacus have been recovered from the late Maastrichtian-aged El Molino Formation, which could potentially suggest a Late Cretaceous occurrence for the family,<ref>{{Cite journal |last1=Near |first1=Thomas J. |last2=Thacker |first2=Christine E. |date=2024-04-18 |title=Phylogenetic Classification of Living and Fossil Ray-Finned Fishes (Actinopterygii) |url=https://bioone.org/journals/bulletin-of-the-peabody-museum-of-natural-history/volume-65/issue-1/014.065.0101/Phylogenetic-Classification-of-Living-and-Fossil-Ray-Finned-Fishes-Actinopterygii/10.3374/014.065.0101.full |journal=Bulletin of the Peabody Museum of Natural History |volume=65 |issue=1 |doi=10.3374/014.065.0101 |bibcode=2024BPMNH..65..101N |issn=0079-032X|url-access=subscription }}</ref> but these teeth show significant differences from modern serrasalmids, and their assignment to the family is uncertain.<ref name=":1" /> Fossils of a living species of ''Colossoma'' from the Miocene have been described, suggesting a very conservative history for a specialized herbivorous fish.<ref name="Nelson">{{cite book |last=Nelson |first=Joseph S. |title=Fishes of the World |title-link=Fishes of the World |publisher=John Wiley & Sons, Inc |year=2006 |isbn=0-471-25031-7}}</ref> All serrasalmine genera had originated by the middle Miocene, with the possible exception of three of the four piranha genera (''Pygocentrus'', ''Pristobrycon'', and ''Serrasalmus'').<ref name="Freeman6" />

==Distribution== Serrasalmids inhabit all major and some minor Atlantic river systems in South America east of the Andes, but have been introduced to other areas.<ref name="Nelson"/> Species range from about 10°N latitude south to about 35°S latitude.<ref name="Freeman2"/>

==Ecology== The diets of the various serrasalmid fishes include seeds, fruits, leaves, and various invertebrate and vertebrate prey, as well as fish flesh, scales, and fins. To emphasize the diversity of diets, authors commonly highlight the fruit- and leaf-eating pacus and the highly carnivorous piranhas. Most in the family other than piranhas are primarily herbivorous. In contrast, piranhas have been long believed to be strict carnivores.<ref name="Freeman6">{{ harvnb|Freeman|Nico|Osentoski|Jelks|2007|pp=6–7}}</ref> Many species change diets depending on age and resource availability.<ref name="Freeman6"/>

The primarily carnivorous piranha group comprises the genera ''Catoprion'', ''Pristobrycon'', ''Pygocentrus'', ''Pygopristis'' and ''Serrasalmus'', but based on phylogeny also the mainly herbivorous (although with omnivorous tendencies) ''Metynnis''.<ref name=Andrade2017>{{cite journal |author=Marcelo C. Andrade |author2=Valéria N. Machado |author3=Michel Jégu |author4=Izeni P. Farias |author5=Tommaso Giarrizzo | year=2017 | title=A New Species of ''Tometes'' Valenciennes 1850 (Characiformes: Serrasalmidae) from Tocantins-Araguaia River Basin Based on Integrative Analysis of Molecular and Morphological Data | journal=PLOS ONE | volume=12 | issue=4 | article-number=e0170053 | doi=10.1371/journal.pone.0170053| pmid=28422969 | pmc=5396854 | bibcode=2017PLoSO..1270053A | doi-access=free }}</ref> The remaining primarily herbivorous species can be divided into two groups based on ecology and, to some extent, phylogeny: ''Colossoma'', ''Mylossoma'' and ''Piaractus'' are mainly found in relatively slow-moving waters, and feed extensively on fruits, nuts and seeds, playing an important role as seed dispersers. ''Mylesinus'', ''Myleus'', ''Ossubtus'', ''Tometes'' and ''Utiaritichthys'' are found in fast-flowing sections of rivers, and mainly feed on aquatic plants, especially Podostemaceae.<ref name=Andrade2017/> ''Myloplus'' mostly feed on plant material and some of its species are phylogenetically related with the previous group, but this genus includes species of both slow and fast-flowing waters.<ref name=Andrade2016>{{cite journal |author=Marcelo C. Andrade |author2=Rafaela P. Ota |author3=Douglas A. Bastos |author4=Michel Jégu | year=2016 | title=A new large ''Myloplus'' Gill 1896 from rio Negro basin, Brazilian Amazon (Characiformes: Serrasalmidae) | journal=Zootaxa | volume=4205 | issue=6 | pages=571–580 | doi=10.11646/zootaxa.4205.6.5| pmid=27988550 }}</ref>

==Relationship to humans== Many serrasalmids are in demand as aquarium ornamentals, and several pacus, such as ''Piaractus'' and ''Colossoma'', are economically important to commercial fisheries and aquaculture.<ref name="Freeman2"/>

Piranhas are generally less valued, although they are commonly consumed by subsistence fishers and frequently sold for food in local markets. A few piranha species occasionally appear in the aquarium trade, and, in recent decades, dried specimens have been marketed as tourist souvenirs.<ref name="Freeman2"/> Piranhas occasionally bite and sometimes injure bathers and swimmers, but serious attacks are rare and the threat to humans has been exaggerated.<ref name="Freeman2"/> However, piranhas are a considerable nuisance to commercial and sport fishers because they steal bait, mutilate catch, damage nets and other gear, and may bite when handled.<ref name="Freeman2"/>

==References== {{Reflist}}

Category:Serrasalmidae Category:Characoidei Category:Fish of South America Category:Extant Miocene first appearances Category:Characiformes families Category:Taxa named by Pieter Bleeker

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