genus Pygocentrus, Red Piranhas

THREE (3) SPECIES of TRUE PIRANHAS and CARIBE
Potentially Dangerous To Man

"...but only four of these are true piranhas. That is, only four of the species are really known to be dangerous to man, and these are the only species invariably known as piranha in Brazil." (Myers, 1972, The Piranha Book pg. 22).

If you do not wish to read this entire page, scroll down towards the bottom and you will see a link to the True Piranha List or click this link.

FROM FRANK MAGALLANES

I first became interested in true piranhas in 1957. Prior to the 1960's few people outside of science circles hardly knew what a piranha was. The few that did only assumed the animal was a man-eater similar to sharks, but would attack in large numbers and turn you into a skeleton in moments if you dared enter its waters. Further, most uninformed people (myself included) assumed the fish was from Africa based on the old Tarzan movies of the 1930's that aired in the 1950's. Even today, people fear the fish based on what former President Theodore Roosevelt wrote in his adventures into the Brazilian wilderness. His tales of the man-eating piranha have even been made into Hollywood movies during the 1970's, where mechanical piranhas are used for the gory scenes. Hollywood made no effort to spare the audience gross inaccuracies about the animal. Not only was its natural behavior over zealously exaggerated, so was the biology and physiology of the fish.

The world considered the piranha blood thirsty man-eaters that flew out of the ocean water to attack humans and chase them around on land!

Largely in great part to Harald Schultz, the Brazilian anthropologist, the image of the piranha has changed considerably (Piranha Fact and Fiction,1964). Schultz stated: For more than twenty years my travels as a student of Indian life in connection with a scientific institute in Brazil have taken me to many far distant parts of the country. In all these years I have never had a harmful experience with these greatly feared piranhas.

The aquarium trade imported few of the species, mostly during the early 1960's did they make it into dealer's tanks as a novelty fish. They commanded high prices, but was not unusual to find the common juvenile P. nattereri offered for sale at today's prices. So in that regard, not much has changed. However, the other Pygocentrus species, such as P. cariba, were not distinguished from P. nattereri. It was simply considered unique only because of the humeral spot. The same went for P. piraya, except for the flaming sides and rayed adipose fin. Both P. cariba and P. piraya did not actually become fully available until the mid 1990's and since then, they have become fairly common in dealers aquariums for individual purchase. Today, scientists are examining the fish more closely than ever before and new information is giving the fish a more serious, well-needed makeover. They are indeed misunderstood and over hyped on the man-eating tendencies. It is now known these fish form loose groups in the wild and do not school (shoal) with any regularity. All the species eat plant matter and seeds, something that in Eigenmann (1917) time would not have been considered nor acceptable to theorize about. It was believed in those days, the piranha would get plant matter from dining on plant eating fish. Those were the scientific explanation for finding fish parts and plant matter in the fishes stomach. P. nattereri, the species often associated with attacks on humans eats on a normal basis, Paspalum repens a tufted annual, with culms sprawling up to 2 meters long; flowering and fruiting August-October. This plant grows quite extensively on the banks of the Amazon and also serve as hiding spots for juveniles of all species.

Two recent publications regarding DNA have been published in 2007. 1) Phylogeography of the piranha genera Serrasalmus and Pygocentrus: implications for the diversification of the Neotropical ichthyofauna (Nicolas Hubert, et al. 2007). 2) Molecular systematics of Serrasalmidae: Deciphering the identities of piranha species and unraveling their evolutionary histories (Barbie Freeman, et al).

In the first paper, their findings suggest that the present results emphasize that an interaction among geology, sea-level changes, and hydrographical created opportunities for cladogenesis in the piranhas at different temporal and geographical scales.

The second paper, they found evidence for a well-supported clade comprised of Pygocentrus, Serrasalmus, and Pristobrycon (in part). The sister group to this clade is also robustly supported, and consists of Catoprion, Pygopristis, and Pristobrycon striolatus. According to these authors, if the term piranha is to refer to a monophyletic clade, it should be restricted to Serrasalmus, Pygocentrus, and Pristobrycon (in part), or expanded to include these taxa plus Pygopristis, Catoprion and Pristobrycon striolatus.

My opinion on this last portion is the authors are misusing the term piranha to imply those fish would be considered true piranha which Myers (1972) has already defined on pg. 22 of The Piranha Book and restricted to certain fish. This published account is ignored by some authorities when it comes to common name usage. So I disagree with this part of the abstract and their conclusion. Both papers state that there is much more work to be done and I wholeheartedly agree with them.

The historical scientific genera names for piranhas have undergone a multitude of changes. Some of these historical names are still found in various State laws where piranhas are prohibited and the invalid names grossly used. Below is the list of authors and the reasoning why these names were originally proposed for those species regarded as true piranhas. Piranhas were only given a cursory glance by historical authors when these fish were first placed. This changed as improved methods to analyze fishes, including usage of radiography of specimens (to better see the bones and teeth) and the most recent method using DNA sequences of mitochondrial (mt) rRNA genes. The number of species loosely called piranhas is around 60 species or more. But only three (3) are true piranha.

Frank Magallanes (L) discussing Los Peces Caribes de Venezuela manuscript with Dr. Anton Phibes.

Though not yet fully resolved, the systematic of Pygocentrus has been revised by Fink (1993) and followed up in subsequent works (Fink and Zelditch 1995, 1997). A diagnosis for the three species comes from the first work (p.665) shown below. Please take the time to read the material throughout the entire OPEFE web site. Each species is covered extensively with material, both scientific and personal knowledge by this author. I have taken the time to fully explore and condense much of the material here for all to read.

Historical lumped all nominal species under genus Pygocentrus because they did consider the morphology and the worn-down palatine teeth. Because of this, it would present a monumental problem since it included species that were not Pygocentrus-like. The list would later be revised into a genera and subgenera using names like; Serrasalmus, Pristobrycon and Pygopristis. These authors included Serrasalmo piraya (Cuvier 1819) a true piranha, Serrasalmo niger (Schomburgk 1841), a pirambeba and Pygocentrus nigricans (Müller & Troschel, 1844), also a pirambeba. The description of the name Pygocentrus itself was very vague. They used historical methods acceptable for that time such as describing as type of body shape, size of mouth, eyes and color. Many of the historical photographs, were not photographs at all but drawings, some colored in by artists at the museum based on what the collector had written from the expedition. The diagnosis of the species was characterized by external observations that applied to almost any species of piranha (except the species piraya with its rayed adipose fin) using words like; lower jaw very heavy, including a convex dorsal outline between dorsal fin and the snout tip, a well-ossified third infraorbital, lack of ectopterygoid teeth, and a few other features, usually vaguely described (Fink 1993). It was at best, difficult to ascertain the actual fish described for this genus name (save one, P. piraya). That is why original descriptions of piranhas are so vague for anyone to determine species easily.

Today, in reviewing various internet forums specializing in piranhas as pets, one can still find vague references in describing their piranha pet similar to the earliest scientist methodology. These hobbyists present out of focus photographs and sometimes no photograph at all, just a description and expect their fish to be identified accurately by this author. An impossible task, yet there are others that try often wrong. There are also situations in these forums where a hobbyist that has little knowledge of the species attempts to give credible information only find out the information is outdated or worse, plain wrong. Such is the type of information found in today's world-wide web. Hobbyist are becoming more sophisticated now and are able to determine factual information from hype or from those amateur's that are building home pages or forums based on erroneous or largely personal opinion based data on their fishes.

While the care and husbandry of these fish are important, everyone should keep in mind that the science is just as important and both go hand in hand in exploring these creatures. New hobbyists should always research their ideas and opinions before expressing them. No sense looking foolish on the web. The science of piranhas has been on-going for over 100 years and much of what today's hobbyists are learning in their aquariums is actually very close to what has already been learned in the field examinations.

Many of the preserved Holotype specimens are no longer in existence for today's scientists to examine. The majority of type specimens were lost or misplaced during World War II. Below is a summary of the changes that have occurred over the years from the beginning.

Pygocentrus

(Müller & Troschel, 1844)

The genus Pygocentrus was erected by Müller & Troschel because they wanted place the type species of Pygocentrus piraya. The fish lacked ectopterygoid teeth (palatine teeth) and possessed a unique feature found only on this species of piranha; a rayed adipose fin and other features pertaining to head, body shape.

Pygocentrus

(Valenciennes, 1850)

This grouping listed one true piranha, two pirambeba, and an invalid name that was probably a pacu (Myletes), respectively; This author placed 5 species in Pygocentrus; Serrasalmo piraya (Cuvier 1819), Serrasalmo niger (Schomburgk 1841), Pygocentrus nigricans (Müller & Troschel, 1844), Pygocentrus nigricans (Spix, 1829) and Pygocentrus palometa (Valenciennes 1850) nomen dubium.

Pygocentrus

(Eigenmann & Eigenmann 1891)

In this grouping, two true piranhas, one pirambeba and caribito were placed; Serrasalmo piraya (Cuvier 1819), Serrasalmo niger (Schomburgk 1841), Pygocentrus altus (Gill 1870), and Pygocentrus scapularis (Gunther 1864).

Pygocentrus

(Eigenmann 1915)

This grouping listed 3 true piranhas and a species still considered valid that was probably a pacu (Myletes palometa = Myleus schomburgkii); The author revised the genus and included 4 species; Pygocentrus piraya (Cuvier 1819), Pygocentrus nattereri (Kner 1869), Pygocentrus notatus (Lutken 1874) and Pygocentrus palometa (Valenciennes in Cuvier & Valenciennes 1850) but as a nomen dubium (= dubious name). No types known.

Gastropristis

(Eigenmann 1915)

The genus name Gastropristis was erected by Eigenmann for Serrasalmo ternetzi (Steindachner, 1908). This singular described specimen was based on the important (and unique) anal fin. The type specimen's anal fin was damaged (mutilated) and the type species eventually lost. No other type from that region has ever been collected that would fit the uniqueness of this described species (see S. ternetzi); One type species; G. ternetzi (Steindachner 1908).

Rooseveltiella

(Eigenmann 1915)

These fish were indeed true piranhas and three (3) species; R. nattereri (Kner 1869), R. notatus (Lutken 1874), and R. stigmaterythraeus (Fowler 1911) were placed under this genus. Both Rooseveltiella (Eigenmann 1915) and Taddyella (von Ihering 1928) were erected to honor President Theodore Roosevelt. These names were substituted because Eigenmann wanted to restrict piraya as a unique Pygocentrus from the rest of the piranhas because of the rayed adipose (considered an apomorphy of this species). So the name Taddyella and Rooseveltiella were the result (Fink 1993). The reason the genus name Rooseveltiella is invalid was because it was already being used on another group of animals (see History of Ichthyology).

Serrasalmus

(Norman 1929)

Norman solely used this genus for all the species of piranhas, pirambeba, caribito and palometa. Effectively lumping them. He did not recognize the subgroups. Both genera Taddyella and Gastropristis were not recognized by Norman (1929) because of the problems associated with them. Taddyella and Gastropristis were younger names than Serrasalmus. Norman also erred egregiously by misspelling the subfamily as "Serrasalmininae".

Pygocentrus

(Fernández-Yépez 1967)

Only one species of true piranha was listed here. The rest were pirambeba and caribito; Places 6 species in this genus; Pygocentrus nattereri (Kner 1869), Serrasalmo niger (Schomburgk 1841), Pygocentrus scapularis (Gunther 1864), Pygocentrus manueli (Fernández-Yépez 1967), Pygocentrus striolatus (Steindachner 1908), and Pygocentrus serrulatus (Valenciennes 1850).

Serrasalmus

(Mago 1970)

Places 2 species in this genus; Serrasalmus nattereri (Kner 1869) and Serrasalmus notatus (Lutken 1874). Both of these species are true piranha.

Serrasalmus (Géry 1976)

In this grouping, non-Pygocentrus (pirambeba, caribito and palometa) and true piranhas were mixed together; Géry split the group into genus Serrasalmus and 2 species in subgenus Taddyella without recognizing this included non-Pygocentrus-like fish. Both Géry (1976) and Machado-Allison (1985) demonstrated that Pristobrycon and Pygocentrus should be maintained because of the number of various species. Géry resurrected Taddyella and placed this as a subgenus to Serrasalmus; The species included Taddyella nattereri (Kner 1869), Taddyella niger (Schomburgk 1841), Tadyella nigricans (Spix 1829), Tadyella notatus (Lutken 1874), and Tadyella ternetzi (Steindachner 1908).

Serrasalmus (Géry 1977)

Again, Géry revised the genus again, this time placing Pygocentrus as a subgenus to Serrasalmus with the species; Pygocentrus piraya (Cuvier 1819), and Pygocentrus manueli (Fernández-Yépez 1967).

Pygocentrus (Machado-Allison 1985; Fink 1991, revised 1993)

This was the first attempt to determine the actual species placement using a new method using Phylogenetics; Dr. Antonio Machado-Allison (1985) revised the nomenclature standing of the piranhas by placing individual species identified by cladistic and Phylogenetic methods into a genera of 4 names; Pygocentrus (true piranhas- 3 species), Serrasalmus (30 or so species), Pristobrycon (10 or more species), and one species in Pygopristis. Other species reviewed included the generic ranks of Catoprion and vegetarian serrasalmin (Piaractus and Colossoma etc.).

Dr. William L. Fink (1991) reviewed the genus, then revised the individual species for genus Pygocentrus (1993) and included an actual key in identifying species of true piranha. Fink based his diagnosis on the following......"Relative to other serrasalmin, Pygocentrus is diagnosable by several features, including prepelvic serrae number, morphology of the gas bladder and skull, and head width. There are three species in the genus: P. piraya, P. nattereri, and P. cariba. P. piraya is diagnosed by presence of adipose fin rays; it is restricted to the Rio Sao Francisco of Brazil. P. nattereri is undiagnosed, and highly variable in pigmentation.

Its included populations are found in tropical and subtropical South America, east of the Andes, including the Amazon basin, the Paraguay and Paraña system, and the rivers of the Guiana's and northeast Brazil.

P. cariba is diagnosed by presence of four supraneurals and a dark, prominent humeral blotch; it ranges through the Rio Orinoco and its tributaries in Colombia and Venezuela. A key to the species is provided (see top of page). All extant types or members of type series are illustrated. Morphometric analyses found no significant shape differences among the species; body shape is extremely stable both ontogenetically as well as within populations.

In contrast, color pattern in both preserved specimens and in life is highly variable ontogenetically and within populations." Fink also made an argument for the placement of the epithet "cariba" noting that an error was made in the original description and epithet.

The genus Pygocentrus is characterized by several anatomical key features;

Species listed with a question mark (?) are those that have not been authenticated by current rehabilitations.

The region marked with an asterisk * very likely pertained to a misidentified species.

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P. nattereri
Argentina	Guyana
Bolivia	Peru
Brazil	Paraguay
*Columbia?	Uruguay
Ecuador