FROM FRANK MAGALLANES

Updated: July 31, 2007

There seems to be some problems among scientists regarding this species validity and its placement as a Serrasalmus. Adding to this complex problem is lack of work by authors to correct the systemic and historical problems with this species. Even the locality is a questionable issue amounting to a huge problem for species placement. All that I can add is that S. serrulatus is found in Amazon river basin, Argentina, Brazil and Peru where many specimens are imported for the aquarium trade (they are often misidentified as S. eigenmanni ). S. eigenmanni was originally limited to Guyana and now appears more widespread than originally believed according to French ichthyologist M. Jégu.  Whether or not the species being discussed is valid or not, certainly those being imported for the trade resemble the group that includes S. hollandi, S. nalseni, S. humeralis and S. eigenmanni. It could also be possible a new species is present that has not been properly described by previous authors. Only time will tell.

The problem with serrulatus is a big one, dating back to Géry when he made S. scapularis a subspecies to S. serrulatus. This is covered in more detail below.

The characters that separate S. serrulatus and S. eigenmanni are few in number, as is the coloration of the fish which is variable with juveniles to adults. Even the number and consistency of body markings is variable inside and out of its populations. I've done my best to isolate the collection points for this particular species.  It is not found elsewhere as of this date. To further complicate the historical problem of this species, it was described from Brazil, but S. eigenmanni was described from Guyana as a unique specimen, later revised by Fink & Machado-Allison (1996 et al.) confirming its presence in Venezuela. S. serrulatus and S. eigenmanni, according to Eschmeyer are found  in the same countries, except S. serrulatus is not in Guyana  according to the cited literatures. Eschmeyer has questions on the fishes cited range by Jégu according to the databanks.

S. nalseni (described from Venezuela) is also a species that also patterns the appearance of S. eigenmanni and S. serrulatus. Hobbyists should keep in mind,  Serrasalmus serrulatus needs a full revision because nominal names were applied to several forms in different countries.

The systemic of piranhas is constantly changing as more current research is being done. It further remains unknown when further systemic work will be accomplished other than DNA and parasitological. M. Jégu is present authority on Brazilian species and his work is not always complete or published. My correspondence with him has not produced any fruitful information on what the future holds regarding these species. It is indeed a messy species group.

Below information is based on available information research and my own opinion. Remarks by me is not to be construed as factual but based on research. S. serrulatus is an obscure species that could fit almost any Pristobrycon-like species.

INTRODUCTION

In the original discussion, Valenciennes (1849) does not mention a terminal band on the caudal fin, Castelnau (1855) affirmed there is a terminal border on the caudal fin and shows it on the plate image. However Géry (1964), based on the holotype specimen, does not present any color that indicates a terminal band. Due to the age and condition of the specimen,  Géry cannot conclude anything. See Jégu remarks under Historical Names.

The bottled specimen above is placed as Pristobrycon serrulatus according to the label. The specimens shown above are in the W. L. Fink laboratory at UMMZ. The specimen shows a faint dark "V" and does seem to present a colored pattern at the caudal edge though very faint. The only recent review was in 1988, Le Genre Serrasalmus dans le bas Tocantins (Brésil) et description de S. geryi. See references below.

DESCRIPTION

A similar species appears to be S. humeralis-gracilior and first mentioned by Eigenmann (1915) and S. hollandi (Reinhardt in Lutken, 1874). There is mention in Norman (1929) where he thought S. eigenmanni looked more closer like S. serrulatus. Norman synonymized S. aureus and S. gymnogenus with S. eigenmanni. S. humeralis was synonymized by Norman under S. rhombeus. Interestingly, S. humeralis was also synonymized with S. marginatus (Valenciennes, 1847). Norman says in part about eigenmanni........

Upper part of body with round dark spots; an indistinct diffuse mark on the shoulder; basal part of caudal dark...further  regarding S. serrulatus... Upper part of body with round dark spots; basal part of caudal dark..  Both these species were compared with S. gymnogenus. Norman concurred that both the two specimens above were certainly identical with gymnogenus. The name S. humeralis-gracilior does not appear again until Géry revised the standing in 1977. He placed this species as a synonym of S. rhombeus.

Norman (1929) said the humeral spot was indistinct diffused in which case the lack of presence of these characters on these fish can be explained and probably attributed to the ecology they are found in. Stress may also be a factor. Norman mentions only one specimen (type of the species) in the original description.  The Norman (1929) citation have a drawing of S. serrulatus and S. eigenmanni......as usual for drawings of that period, they both look similar to each other except the S. eigenmanni 'V' type caudal fin is more prominent than S. serrulatus. Machado-Allison and Fink (1996) mentioned that S. eigenmanni has round spots later (during ontogeny) developing a combination round spots and some vertical long ones. Jégu in "Le genre Serrasalmus..." compared S. eigenmanni with S. humeralis...both species were quite close, but Jégu separated S. humeralis as a distinct species from S. eigenmanni based on other characters not found on S. eigenmanni.

I remain uncertain on this species, since I have very little information on it from other localities including lack of photographs, and of course the historical problems with the humeralis group as a whole. Further complicated by historical description problems that included many fish in this group on a limited range of examination. The only present review was Fink and Machado-Allison (1996) pertaining to the Venezuela species. But subsequent follow ups by Jégu has left  me very confused on species identification and its natural range that is beyond my understanding at this time. For the time being, S. eigenmanni, S. hollandi, S. humeralis, S. nalseni and S. serrulatus, may be species that will remain an enigma for me. With the influx of specimens at the hobbyist level and lack of actual locality data, will not make identifying this species any easier. Especially, those that might appear to be S. serrulatus, but may be S. eigenmanni instead.

Gill (1871) compared this species with Pygocentrus altus but did little to justify  P. altus description by stating only that it was "Nearly related to P. scapularis (Serrasalmo scapularis)....." the fish was mentioned probably because S. scapularis has 28 belly serrae. Fink (1993) examined 3 syntypes of S. scapularis and found the species serrae count are 28, 30, and 32. Géry (1972) placed P. scapularis as a subspecies to S. striolatus. Géry recognized only 12 species of piranha on the entire continent of South America! Nomenclature problems can be traced to Dr. Géry when he began assigning species as subspecies. In this situation by Dr. Géry placing S. serrulatus a poorly described species as a subspecies to a better described taxon.

The bionomen S. serrulatus has precedent over all the other published names since it was first (Valenciennes 1850), thus it is likely to stay and the latter be junior synonyms, if the fish is revisited by a competent authority. 

HISTORICAL NAMES

• Serrasalmo scapularis Günther 1864:368 [Cat. Fishes v. 5; ref. 1974]. Essequibo R., Guyana. Syntypes: BMNH 1864.1.21.34-36 (3), 1971.5.10.58 (1): Synonym of Serrasalmus serrulatus (Valenciennes 1849), but a valid subspecies -- (Géry 1972:222: Synonym [of the younger] Pristobrycon striolatus (Steindachner 1908) -- (Jégu in Reis et al. 2003:188: Perhaps should be considered as valid as Pristobrycon scapularis (Günther 1864). Pristobrycon striolatus (Steindachner 1908).

• Pygopristis serrulatus Valenciennes in Cuvier & Valenciennes 1850:300 [Hist. Nat. Poiss. v. 22; ref. 1014]. Amazonas, Brazil. Holotype (unique): MNHN A-9898. Type catalog: Bertin 1948:25-26: Valid as Serrasalmus serrulatus (Valenciennes 1850) -- (Géry 1972:221, Ortega & Vari 1986:9, Jégu in Reis et al. 2003:192, López et al. 2003:32, Menni 2004:78. Serrasalmus serrulatus (Valenciennes 1850). 

Géry 1972 placed S. scapularis as a synonym to S. serrulatus, but considered it a subspecies. Jégu had some reservations about that placement.

LIST FOR ABOVE PHOTOS

1. Castelnau S. serrulatus plate image.

2. Specimen unknown collection point. Listed as S. serrulatus.

3. Drawing of Pristobrycon serrulatus (Géry, 1963).

4. Specimen jar holding Pristobrycon serrulatus (UMMZ) photo by Frank Magallanes.

 

Image 1: My own research, I found little information concerning this species, it might not even be the right species. Closely resembles S. eigenmanni and P. striolatus.  Two (2) photos shown here may resemble S. serrulatus. As seen on the photo, the fish has an anal fin that has a margin not touching the edges., resembling a black line. This feature is also found on the caudle fin edge, similar to S. spilopleura and S. maculatus. However, another species that resembles this image and Image 2 below,  is Pristobrycon calmoni. However that species is in Brazil and Venezuela,  not Peru according to current field collections.

 

Image 2: The specimen possesses large ovals on the upper body in combination with vertical elongated spots,  quite similar to S. eigenmanni.  Body is very compressed laterally and discoid. Below the flank and the belly region is heavily with small round spots and bars. Serrae are well formed and large. A faint large humeral spot is apparent behind the gill. A black band transects the eye. A faint caudal band seems apparent in the preserved specimen, along with a dark "V" pattern of the basal region.  Adipose fin is large with a black margin bordering the edge. The eye (iris) is black and a black band transects the iris and orbit with is clear. Body is high and discoid, bright silver with a black humeral spot on the flank below the lateral line behind the gill. Cheek yellow-gold with red tinting. Anal fin is tinted a yellowing-orange. Pectoral fins are tinted orange. All other fins appear to be hyaline.

LOCALITY

Amazon R. basin and (?) Essequibo R. basin: Amazon (?), Brazil, Guyana (?) and Peru; Argentina. 

MAXIMUM SIZE

19.0 cm SL (7.4 inches SL or approximately 9  inches TL)

CONTRIBUTORS AND ADVISERS

• Fink, William L.

• Machado-Allison, Antonio

• Schleser, David M.

REFERENCES 

USE YOUR BACKSPACE TO RETURN OR CLICK HERE TO RETURN SERRASALMUS LIST

RETURN RESEARCH PAGE

TO RETURN HOME CLICK HERE.

The OPEFE web site and its contents; is disclaimed for purposes of Zoological Nomenclature in accordance with the International Code of Zoological Nomenclature, Fourth Edition, Article 8.3 and 8.4. No new names or nomenclature changes are available from statements at this web site.

Copyright© 1994-2009 Oregon Piranha Exotic Fish Exhibit (The OPEFE fish exhibit is permanently CLOSED as of 2000) Sutherlin, Oregon. Information posted on this web site is archival data on fish scientific classifications and other information. DISCLAIMER: The copyrighted material may not be used for any purpose other than private study, scholarship or research. Cited information requires credit and this link www.opefe.com. All rights reserved. All images shown  (unless otherwise noted) is property of OPEFE. 

UPDATED: 07/10/2009