Ichthyology Research


The biodiversity of the neotropical characiform fishes is poorly understood. Each year ten to twenty new taxa were described (including genera). That’s why also our knowledge about the phylogeny of this group which is extreme rich on species is very poor. 
We discovered from 2005 bis 2013 eigtheen new species, three new genera and one new tribus (Zarske, 2007, 2008a,b, 2009; Zarske & Géry, 2006a,b,c,2007, 2008, 2011a,b, 2012, 2013; Zarske, A., Le Bail, P.-Y. & Géry, J. (2006, 2010). Among them there are some beautiful fishes like Trochilocharax ornatus Zarske, 2010, Nannostomus rubrocaudatus Zarske and Nannostomus nigrotaeniatus Zarske, 1913.
But not only the descriptions of new species are important. There are a lot of species with incorrect and wrong information. So re-descriptions of named species are often more useful. With the correct knowledge of the named taxa it is often possible to distinguish closely related species. Characidium borelli (Boulenger, 1895), Ch. macrolepidotum (Peters, 1886), Copella nattereri (Steindachner, 1876) and Boehlkea fredcochui Géry, 1966 were some of these cases. In an earlier case we were able to show that a taxon which was treated as extinct (Agoniates halecinus Müller & Troschel, 1848) is rearly widly distributed and commun in the northern part of South America (Zarske & Géry, 1997). Such works led to changes in the names of well-kown species.


Axel Zarske · Senckenberg Dresden; Gert Füllner · Sächsisches Landesamt für Umwelt und Geologie, Referat Fischerei, Königswartha; & Matthias Pfeifer · Sächsisches Landesamt für Umwelt und Geologie, Referat Fischerei

The local ichthyofauna was an important field of research of our museum in the past. The most important paper about this was written by Leonhardt & Schwarze (1903). There were a lot of valuable historical specimens in the ichthyological collection. These specimens are often the one and only objective evidence of this extinct species in Saxony. 
With this traditional background we conduct numerous investigations especially in the river Elbe in the last years. This research take place in cooperation with the Sächsische Landesanstalt für Umwelt und Geologie, Referat Fischerei, Institut für Hydrobiologie der Technischen Universität Dresden and the Sächsischer Anglerverband.
It was very interesting to observe the changes in the composition of the species during the improvement of the quality of the water of the river Elbe. In 1989 the river Elbe was the most polluted river in Germany. Nevertheless there were a lot of fishes in the river, more than today. In the process of the clarification of the water there were some changes in the fish fauna. Now we have more species but not more specimens (biomass) in the river Elbe than in 1989.
In 1996 we published our results in the booklet „Die Fischfauna von Sachsen. Rundmäuler, Fische, Krebse. Geschichte, Verbreitung, Gefährdung, Schutz“. This booklet was exhausted in a short time. So we published in 2005 a very enlarged and revised edition as „Atlas der Fische Sachsens. Rundmäuler, Fische, Krebse. Geschichte, Verbreitung, Gefährdung, Schutz”. A section for the determination of the fishes and a key complete the book. This edition received very good book reviews and is now also exhausted. The Atlas is today only available in the internet at an expansive price (up to 140 to 280 €).
Now we have made more investigations on the distribution of the fishes in Saxony and have a lot more records. So we plan the third edition in 2015.


Historical type material is often the only source to clarify the status of problematical taxa. Mostly the old original descriptions and images give not enough information so that a re-investigation is necessary. There are a lot of historical types of the members of the order Characiformes in the Museum of Natural History of Berlin. The exactly knowledge of this types is very important for the discovery of new, up today undescribed species. If the type specimens of the problematical species are undiscoverable so nomenclatural problems are often insoluble. So it is possible that species which are very common in nature and also in captivity are often known under a wrong name for a long time. During these investigations a lot of types from Carl Eigenmann (1863-1927) were re-discovered in the ichthyological collection of the Museum of Natural History of Berlin.

One example is the Rautenflecksalmler. This species was known as Hemigrammus caudovittatus Ahl, 1923 for a long time. In 1995 Zarske & Géry realized that this fish which is cultivated in captivity since 1922 under this name belongs really to the species Hyphessobrycon anisitsi Eigenmann, 1907. But the type-species of this taxon were lost, so that we are unable to solve this problem. During this research we found the lost type specimens (146 exemplars) of H. caudovittatus. So we are able to declare Hemigrammus caudovittatus Ahl, 1923 as a synonym of Hyphessobrycon anisitsi Eigenmann, 1907.

Also the identity of Xiphorhamphus pericoptes Müller & Troschel, 1844 was obscure for a long time. We are able to show in this research that this name is a synonym of Oligosacus hepsetus (Cuvier, 1829).


The taxonomic relationships within the neotropical characiform genus Metynnis Cope, 1878 (common name: Silverdollars) are absolutely unsatisfactory today. Ahl (1924, 1925, 1927, 1931) distinguished 24 taxa. Gosline (1951) reduced the number of valid species to six. Ahl and Gosline have not investigated enough the type-specimens of the earlier described species. Moreover, they did not have enough material available in order to estimate the variability of each species. The main part of the material of Ahl has no exact locality. The type-specimens of M. goeldii Eigenmann, 1903, M. orinocensis (Steindachner, 1908) and M. fasciatus Ahl, 1931 were lost at that time. Metynnis unimaculatus Steindachner, 1908 is a junior-synonym of Mylossoma duriventris (Cuvier, 1818). A redescription of the type-specimens was the first step of a revision of the whole genus Metynnis (Zarske & Géry, 1999). All nominal taxa were described and a type-specimen or topotypical specimen was figured for each of them. Metynnis altidorsalisIn some cases topotypical material is used for the proper characterization of the species. The following species were considered as valid: M. hypsauchen (Müller & Troschel, 1844), M. maculatus (Kner, 1858), M. lippincottianus (Cope, 1870), M. luna Cope, 1878, M. mola Eigenmann & Kennedy, 1903, M. orinocensis (Steindachner, 1908), M. guaporensis Eigenmann, 1915, M. altidorsalis Ahl, 1924, M. argenteus Ahl, 1924, M. otuquensis Ahl, 1924 and M. fasciatus Ahl, 1931. A lectotype is designated for M. maculatus (Kner, 1858), M. orbicularis (Steindachner, 1908) and M. ehrhardti Ahl, 1927.
Metynnis longipinnis
In a next step two new species were described and a syntype of M. goeldii Eigenmann, 1903 was re-discovered. Metynnis longipinnis Zarske & Géry, 2008 from the río Casiquiare drainage in Venezuela is closely related to Metynnis hypsauchen (Müller & Troschel, 1844) according to its features (1) high number of gill-rakers, (2) long adipose fin, (3) deep body, (4) short head and (5) long occipitale and is clearly defined because of (1) the high number of serrae (36–37 vs. 27–32 of M. hypsauchen), (2) the small scales (91–93 vs. about 75–83), (3) uniformly silver colouration and (4) the extremely elongated dorsal fin and anal fin. From Metynnis altidorsalis Ahl, 1924 Metynnis longipinnis is clearly differentiated by its (1) number of gill-rakers (30–33 vs. 20–25 for M. altidorsalis), (2) the number of branched anal rays (37–40 vs. 32–37 for M. altidorsalis), (3) the number of serrae (36–37 vs. 29–35 for M. altidorsalis) and (4) the length of the occipitale (18.94–20.78 % SL vs. 11.7–15.6 for M. altidorsalis). Further more, M. longipinnis has a longer adipose fin (20.00–20.78 % SL vs. 11.8–16.2 for M. altidorsalis) and an elongation of the rays of dorsal and anal fin (vs. not elongated for M. altidorsalis). M. luna Cope, 1878, M. orinocensis (Steindachner, 1908) and M. guaporensis Eigenmann, 1915 are differentiated by its higher number of gill-rakers and larger head length. M. lippincottianus (Cope, 1870) has a completely different colouration.Metynnis polystictus

The next step includes a re-description of all valid species and a phylogenetic analyse of the genus.