Serrasalminae

Taxobox
name = Serrisalminae
fossil_range = Miocene - Present


image_width = 240px
image_caption = "Serrasalmus manueli"
regnum = Animalia
phylum = Chordata
classis = Actinopterygii
ordo = Characiformes
familia = Characidae
subfamilia = Serrasalminae
subdivision_ranks = Genera
subdivision = "Acnodon" "Catoprion" "Colossoma" "Metynnis" "Mylesinus" "Myletes" "Myleus" "Myloplus" "Mylossoma" "Ossubtus" "Piaractus" "Pristobrycon" "Pygocentrus" "Pygopristis" "Serrasalmo" "Serrasalmus" "Tometes" "Utiaritichthys"

Serrasalminae is a scientific classification of fish within the Characidae family. The name Serrasalminae means "serrated salmon family", which refers to the serrated keel running along the belly of these fish.

Common names

Fish classified as Serrasalminae are also known by the following common names:
*Pacú
*Piranha
*Silver dollar

These common names generally are applied according to differing dental characteristics and feeding habits.

Taxonomy

Currently, the fish of this group are classified as a subfamily of Characidae. However, there are some sources that classify these fish in their own, separate family, Serrasalmidae. This is because the relationship of fish of this group to other characiforms has yet to be determined.cite journal|url=http://www.mapress.com/zootaxa/2007f/zt01484p038.pdf|title=Molecular systematics of Serrasalmidae: Deciphering the identities of piranha species and unraveling their evolutionary histories|first=Barbie|last=Freeman|coauthors=Nico, Leo G.; Osentoski, Matthew; Jelks, Howard L.; Collins, Timothy M.|journal=Zootaxa|volume=1484|pages=2|year=2007|format=PDF] The taxonomy and systematics of piranhas and their relatives are complicated and much remains unsettled. Consequently, both species identification and phylogenetic placement of many taxa are problematic.

However, the ongoing classification of these fish is difficult and often contentious, with ichthyologists basing ranks according to characteristics that may overlap irregularly (see Cladistics). DNA research sometimes confounds rather than clarifies species ranking. Ultimately, classifications can be rather arbitrary.cite web| last = Magallanes | first = Frank | title = Subfamily Serrasalminae | url = http://www.opefe.com/serrasalminae.html | publisher = Oregon Piranha Exotic Fish Exhibit | date = 2006-04-06 | format = Website]

On the other hand, compared to many neotropical fish groups, this is well defined, and there is wide agreement concerning which genera and species should be included.Freeman, et al., 2007, pg 3.]

Fossil record

The fossil record available for fishes of this group, particularly for piranhas, is relatively sparse. Most known fossils are from the Miocene, although a few unidentified forms are considered Paleocene and two reportedly date to as early as the Late Cretaceous. Fossils of a living species of "Colossoma" from the Miocene have been described, suggesting a very conservative history for a specialized herbivorous fish.cite book|title=Fishes of the World|last=Nelson|first=Joseph S.|publisher=John Wiley & Sons, Inc|year=2006|isbn=0-471-25031-7] All serrasalmine genera had originated by the middle Miocene, with the possible exception of three of the four piranha genera ("Pygocentrus", "Pristobrycon", and "Serrasalmus").

Distribution

Serrasalmines are distributed in South America, but have been introduced to other areas. Species are distributed in all major and some minor Atlantic river systems from about 10° N latitude south to about 35° S latitude.

Description

Serrasalmines are medium to large-sized characids (up to about 1 m long) generally characterized by a deep, laterally compressed body with a series of mid-ventral abdominal spines or scutes, and a long dorsal fin (over 16 rays). Most species also possess an anteriorly-directed spine just before the dorsalfin extending from a supraneural bone; exceptions include members of the genera "Colossoma", "Piaractus", and "Mylossoma".

Most serrasalmines have about 60 chromosomes, though the range is anywhere from 54 to 62. However, "Metynnis" has 62 chromosomes, as does "Catoprion", "Pristobrycon striolatus", and "Pygopristis".

Ecology

As a group, the diets of serrasalmid fishes are extremely broad and include seeds, fruits, leaves, various invertebrate and vertebrate prey, as well as fish flesh, scales, and fins. To emphasize the polarity of diets, authors commonly highlight the fruit- and leaf-eating pacus and the highly carnivorous piranhas. Most non-piranhas in the family are primarily herbivorous. In contrast, it was long believed that piranhas were strict carnivores.Freeman, et al., 2007, pg 6–7.] However, many species are known to adopt multiple diets depending on age and resource availability.

Relationship to humans

Many members of this group are in demand as aquarium ornamentals, and several pacus, such as "Piaractus" and "Colossoma", are economically importantto commercial fisheries and aquaculture. 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. Piranhas occasionally bite and sometimes injure bathers and swimmers, but truly serious attacks are rare and the threat to humans has been largely exaggerated. 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.

References