Corresponding author: Tomáš Scholz (
Academic editor: B. Georgiev
An exhaustive literature search supplemented by a critical examination of records made it possible to present an annotated checklist of tapeworms (
Alves PV, de Chambrier A, Scholz T, Luque JL (2017) Annotated checklist of fish cestodes from South America. ZooKeys 650: 1–205.
Tapeworms (
Cestodes parasitizing elasmobranchs and teleost fishes in at least one stage of development comprise one of the most diverse lineages of tapeworms (
South America is a megadiverse continent, including at least five of the world’s biodiversity ‘hotspots’, more than 30.000 km of coastline and two of the 10 largest freshwater drainage systems of the world, i.e. the Amazon and Paraná River basins, which is reflected in its species-rich ichthyofauna (
Studies on fish cestodes from South America date back to the early 19th Century, when C. A. Rudolphi described
Detailed taxonomic studies combining morphological and molecular approaches have recently expanded our knowledge at lower and higher taxonomic levels, mostly under the framework of the National Science Foundation (Planetary Biodiversity Inventory program) funded project called “A survey of the tapeworms (
Parasite-host and host-parasite checklists for fish cestodes from South America were compiled on the basis of an exhaustive search of literature published until August 2016; abstracts of meetings, theses and reports without primary data were not considered. The bibliographic search was complemented by the information gathered from Global Cestode Database
The species are arranged according to taxonomic categories and are presented in alphabetical order followed by data on their hosts (species name, class and family), habitat, site of infection, stage of development, marine ecoregion according to
Host species are arranged in taxonomic and then alphabetical order. The scientific names of hosts have been updated based on
The following abbreviations are used for collections:
The British Museum (Natural History) Collection at the
Coleção Helmintológica do Instituto Oswaldo Cruz, Rio de Janeiro, Brazil
Harold W. Manter Laboratory of Parasitology,
Departamento de Zoología de Invertebrados (Parasitología), La Plata, Argentina
Museum der Naturkunde für Humboldt Universität zu Berlin, Germany
The following abbreviations are used for marine ecoregions according to
Juan Fernández and Desventuradas
North Brazil Shelf
Tropical Eastern Pacific
Tropical Northwestern Atlantic
Tropical Southwestern Atlantic
Warm Temperate Southwestern Atlantic
Warm Temperate Southeastern Pacific
The following abbreviations are used for molecular markers:
small subunit of the nuclear ribosomal RNA gene
first nuclear ribosomal internal transcribed spacer
5.8S ribosomal RNA gene
second nuclear ribosomal internal transcribed spacer
large subunit of the nuclear ribosomal RNA gene
large subunit of the mitochondrial ribosomal RNA gene
cytochrome
The following abbreviation is used for records of metacestodes in the host-parasite list:
larvae
* Asterisks in the parasite-host list indicate the type species of the genus.
[Syns.
Notes: type host.
[Syns.
Notes: type host.
Notes: type host. Sequences of
[Syn.
Note: R. Kuchta (pers. comm.) suggested that this report might be wrong.
adult; Magellanic; Argentina, Chile (
Note:
Note:
Notes: type host. R. Kuchta (pers. comm.) suggested that all reports from
Notes: type host. R. Kuchta (pers. comm.) suggested that all reports from
[For synonyms, see
Notes: these reports from South America are probably result of the import of common carp from Europe to Brazil (
Notes: host reported as
Note: tapeworms reported as ‘
Notes:
Notes: type host; it was originally reported as
Note: all but one authors reported the cestode as
Note:
Notes: type host.
[For synonyms, see
Notes: type host. The tapeworms were reported as
[Syn.
Notes:
Note:
Note: type host.
Note: type host.
Notes: type host.
Note: reported as
Note: reported as
Note: reported as
Note: reported as
Note: host reported as
Note: reported as
[Caryophyllidean tapeworms do not occur in the Neotropical region, where their common hosts, i.e. cyprinid and catostomid fishes, are absent; therefore, these reports need verification]
Note: introduced fish host (
Note: type host.
Note: type host.
Note: type host.
[Syn.
Note: tapeworms reported as
Note: these specimens probably belong to
[For synonyms, see
[For synonyms, see
[For synonyms, see
Notes: type host. Sequences of partial
[Syn.
Notes: type host.
[Syn.
Notes: type host; it was originally reported as
[Syn.
Notes: type host.
[Syn.
Note: type host.
Note: two morphotypes were distinguished by
[For synonyms, see
Note:
Note:
Note:
Note: the author reported the host as
Notes: the genus
Note:
Note: host reported as
[For synonyms, see
Notes: tapeworms described as
[For synonyms see
Note: the authors reported the tapeworms as
Note: host reported as
Note: host reported as
[Reports from freshwater fishes most likely correspond to
Notes: host reported as
Note:
Note: host reported as
Note: host reported as
[Larval stages found in the body cavity and mesentery are most likely species of
intestine; metacestode; Magellanic; Chile, Falkland Islands (
Note:
[Syns.
Note: tapeworms reported as
Notes: type host; it was reported as
[Syn.
Note: type host.
[Syn.
Notes: type host.
Note: type host.
Note: type host.
[Syn.
Notes: type host; it was reported as
Note: type host.
Note: type host; it was reported as
Note: type host.
Note: type host; it was reported as
Notes: type host. Elasmobranchs are the typical definitive host for
Note: type host.
Note: type host.
Note: type host.
Unidentified ray host (
Note: this species was described from
Note: type host.
Note: type host.
Note: type host.
Note: type host.
Note: type host.
Note: type host; it was reported as
Note: type host; it was reported as
Note: type host; it was reported as
Note: type host.
Note: type host.
Note: host reported as
valve; adult; Amazon River basin; Peru (
Note: type host.
Note: type host.
valve; adult;
Notes: type host.
Notes: type host.
Note: type host; it was reported as
Note: type host.
Notes:
Note: type host; it was reported as
Note: type host.
Note: type host.
Note: type host.
Note: the authors distinguished two morphotypes.
Note: host reported as
Note: type host.
[Syns.
Note:
Notes: type host; it was reported as
Note:
Note: host reported as
Notes: type host.
Notes: type host.
Notes: host reported as
Note: type host.
Note: type host.
Note: type host.
[Syn.
Note: tapeworms reported as
Notes: type host; it was reported as
Note:
Note: host reported as
Note: these cestodes may represent an undescribed species of the genus (
Note: these cestodes may represent an undescribed species of the genus (
[Even though recent molecular data suggest that most of the traditionally recognized subfamilies are artificial, i.e. non-monophyletic, we are following Woodland’s subfamilial classification for practical reasons]
Notes: host reported as
[Syn.
Notes: host reported as
Notes: type host; it was originally reported as
Note: host reported as
Notes: type host.
River basin; Brazil (
Note: this host should be synonymized with
Notes: type host.
Tocantins-Araguaia River basins; Brazil (
Note: type host.
Notes: type host. In type material,
[Syn.
Notes: type host. Sequences of complete and partial
Notes: type host; it was reported as
[Syn.
Notes: tapeworms reported as
River basin; Brazil (
Notes: type host; it was reported as
[Syns.
Note:
Note:
Note:
Note:
[Syns.
Notes: type host.
Notes: tapeworms reported as
River basin; Brazil (
Notes: host reported as
[Syn.
Note: type host; it was originally reported as
[Syns.
Note: the specimens studied by
Note: type host.
Note: host reported as
Note: sequences of partial
[Syn.
Note: host reported as
Notes: type host; it was originally reported as
[Syns.
Notes: type host.
[Syns.
Note: type host; it was originally reported as
Note: type host.
[Syns.
Notes: type host; it was originally reported as
Note: host reported as
Note: type host.
[Syns.
Notes: type host; it was reported as
Note: they reported the tapeworms as
Note: type host.
[Syn.
Notes: this host is assumed to be the type, because all possible fish hosts cited by
Notes: type host. Sequence of partial
[Syn.
Notes: type host. Sequence of
[Syn.
Note: type host.
[Syns.
Note: sequence of
Note: type host.
Note: type host.
and Paraná River basins; Argentina, Brazil, Paraguay, Peru (
Notes:
[Syn.
Notes: type host; it was reported as
[Syns.
Note: type host.
Note: probably
River basin; Brazil, Paraguay (
Notes: type host. Sequence of partial
Note: type host.
Notes: type host; it was reported as
[Syn.
River basin; Argentina, Brazil, Paraguay (
Notes: type host; it was reported as
Note: type host.
Note: type host.
Note: type host.
[Syns.
Notes: type host; it was originally reported as
River basin; Argentina, Brazil (
Notes: host reported as
Notes: sequences of complete IT2 (
Note: host reported as
Note: type host; it was originally reported as
Note: sequence of complete
River basin; Brazil (
Notes: host reported as
River basin; Paraguay (
Note: host reported as
[Syn.
Notes: type host; it was originally reported as
Notes: host also reported as
Note: type host.
Notes:
Notes: type host; it was originally reported as
Notes: host originally reported as
Notes: type host. Sequence of partial
Note: type host.
Note: type host; it was originally reported as
[Syn.
Note: type host; it was originally reported as
[Syn.
Notes: type host.
[Syns.
Notes: type host. Sequences of partial
and Paraná River basins; Paraguay, Peru (
Notes: type host. Sequence of partial
River basin; Peru (de Chambrier et al. 2015).
Note:
Notes: type host; it was reported as
Note: sequence of partial
[Syns.
Notes: type host; some authors assumed
Note: type host.
Note: type host.
Note: type host.
[Syn.
Note: type host.
Note: host originally reported as
Note: type host.
Note: type host.
Notes: type host; it does not occur in the Paraná River basin (
Note: type host; it was originally reported as
Note: host originally reported as
Note: type host; it was originally reported as
Note: type host; it was most likely mistaken (see notes for
Note: type host; it was originally reported as
Note: type host.
Note: type host.
Note: they named this morphotype as
Note:
Note: the host species was most likely misidentified (see notes on p. 50 for more details).
Note: they named this morphotype as
Note: type host; it was reported as
[Syn.
Notes: type host. Sequences of partial
Note: type host.
Notes: tapeworms reported as
[Syns.
Notes: type host. Sequences of partial
[Syns.
Notes: type host; it was originally reported as
Note:
[Syn.
Note: type host.
[Syns.
Notes: host originally described as
Note: type host.
[Syn.
Note: type host.
Notes: type host. Sequences of partial and complete
Note: sequence of
Notes: type host. Tapeworms reported as
Note: type host.
Notes: type host; it was originally reported as
Notes: type host; it was originally reported as
Notes: type host; tapeworm reported as
Notes: type host; it was originally reported as
[Syn.
Notes: type host;
Note: host reported as
[Syns.
Notes: type host; it was reported as
Note: sequence of partial
[Syn.
Notes: type host; it was reported as
[Syns.
Note: records of
Notes: type host. Sequence of partial
Note: type host;
Note: type host.
[Syns.
Notes: type host.
[Syns.
Notes: see p. 40 in the section of
Note: type host; it was reported as
[Syn.
Notes: type host. Sequences of partial
Note: type host.
[Syn.
Notes: type host; it was reported as
Note: type host.
[Syns.
Notes: type host; it was originally reported as
[Syn.
Note: type host. Sequences of partial
cavity, intestine, stomach; metacestode; Amazon River basin; Brazil (
Note: the authors did not provide any molecular data on these larvae; therefore, this report needs verification.
and metacestode; Amazon and Paraná River basin; Brazil, Paraguay (
Notes: type host. Sequences of partial
Note: type host.
Note: they reported this species as
Note: type host.
Notes: type host; it was identified as
Note: host reported as
Note: type host; it was originally reported as
[Syn.
Note: records of this species from the Paraná River basin need verification, because
Notes: type host. Host reported as
Note: they reported this species as
Notes: type host. Sequences of partial
Notes: host reported as
Notes: tapeworms reported as
Note: host reported as
[Syns.
Note: host reported as
Notes: host also reported as
Note: type host; it was originally reported as
Unidentified fish (
Notes: type host. Sequences of complete
Note: these tapeworms belong to a new species and genus that will be described in a forthcoming paper.
Note: certainly not a larva of the
Note: introduced fish host (
Note: introduced fish host (
Note: introduced fish host (
Note: the author reported the presence of operculate eggs released from a contracted proglottid, but this unique report needs confirmation.
Note: host reported as
Note: host reported as
Note: host reported as
Note: certainly not a larva of the
Hybrid fish host (
Note: the host is a hybrid of
Notes: type host; it was reported as
[Syns.
‘
specific locality (
[Syns.
‘
Note: host reported under four different names,
Note:
Note:
Note: for details on the taxonomic status of this species, see
Note: type host.
[Syns.
Note: tapeworms reported as
[Syn.
Notes: position of the species within
Note: type host.
[Syn.
Notes: type host.
Note: host reported as
Note: type host.
[Syns.
Notes: type host.
[Syns.
Note: tapeworms reported as
Note: tapeworms reported as
[Syns.
Note: tapeworms reported as
[Syns.
Notes: type host. Tapeworms reported as
[Syns.
Note: tapeworms reported as
Note: tapeworms reported as
Notes: tapeworms reported as
Notes: tapeworms reported as
Note: host reported as
Notes: host reported as
Note: type host.
[Syns.
Notes: tapeworms reported as
Note: host reported as
Notes: type host.
Notes: type host. This species somewhat resembles members of the genus
[Syns.
Note: tapeworms reported as
[Syn.
Notes: type host. Sequences of partial
[Syn.
Note: tapeworms reported as
Note: type host; it was reported as
Note: host reported as
Notes: type host; it was reported as
Note: host reported as
Note: type host; it was reported as
Note: host reported as
Note: type host; it was reported as
Note: type host.
Notes: type host. Sequences of partial
Note: type host; it was reported as
Notes: type host.
Note: sequence of
Note: accidental host (
Note: accidental host, according to
Notes: accidental host. Sequence of
Notes: the authors distinguished four morphotypes of the host. Sequence of
Note: type host.
Note: type host.
Notes: type host. Sequences of
Note: type host.
Note: type host; it was reported as
Note: type host.
Note: type host.
[Syn.
Note: sequences of
Note: sequences of
Note: host reported as
Note: type host; it was reported as
Note: type host.
Note: type host.
Note: type host.
Notes: they reported hyperparasitism caused by metacestodes of proteocephalids. Sequences of partial
Note: host reported as
Notes: type host.
[Syns.
Note: host reported as
Notes:
Notes: type host; it was reported as
Note: sequence of partial
Notes: type host; it was originally reported as
Notes:
Notes: type host.
[Syn.
Notes: type host.
Note: sequence of partial
[Syn.
Note: type host; it was originally reported as
Note: sequence of partial
Notes:
Note: the authors reported hyperparasitism caused by metacestodes of proteocephalids.
Note: sequence of partial
[Syns.
Note: type host. Tapeworm originally described by
Note: type host.
[Syns.
[Syn.
Note: type host.
Notes: host reported as
[Syn.
Notes: type host. The genus
Note: type host.
Note: the species is likely a member of the
Notes: type host. This species is likely a member of the
Notes: type host. The tapeworm is likely a member of the
Note: type host.
Notes: type host. This species was originally described as
[Syns.
Note: type host.
Note: type host.
Note: type host; it was reported as
Note: type host.
[Syn.
Note: type host.
Notes: type host.
[Syns.
Note: type host.
[Syn.
[Syns. of
Notes: type host.
‘
Note: host reported as
Note:
given; metacestode;
Note: host reported as
Note:
infection not given; metacestode;
Notes: host reported as
Note: host reported as
infection not given; metacestode;
Note: host reported as
Notes:
Note: host reported as
Note: host reported as
Note: host reported as
given; metacestode;
Note: host reported as
Note:
Note: host reported as
Note:
Note: host reported as
[Syns.
Note: host reported as
Note:
[For synonyms, see
Note: tapeworms reported as
[For synonyms, see
Note: the cestodes were collected by Göldi in 1896.
Note: host reported as
internal organs, serous membrane; metacestode;
Note: host reported as
Note: host reported as
Note: host reported as
Note: host reported as
[Syns.
Note: host reported as
Note: type host; it was reported as
[Syns.
Notes: type host; it was originally reported as
arches, mesentery, kidney; metacestode;
[Syns.
Note: host reported as
[Syns.
Notes: type host. Carvaval and Rego (1983) re-identified the larvae collected by
Note:
Note: after morphological re-evalution of specimens deposited by
cavity; metacestode;
Note:
[Syns.
Notes: tapeworms reported as
Note: this species was described from fishes in the North Pacific Ocean and it is morphologically similar to
Note: host reported as
Notes: type host; it was reported as
[Syns.
Note:
Note:
Note: type host.
[For synonyms, see Beveridge and Campbell (2013)]
Note:
Note: the specimens are most likely
Note:
[Syn.
Note: host reported as
[Syns.
Note:
Note: host reported as
given; metacestode;
caeca; metacestode;
stage of development not given;
Notes: host reported as
Note: type host; it was reported as
[Syn.
Note: type host.
Note: host reported as
[Syns.
Note: type host.
[Syns.
Note: host reported as
Note: host reported as
Note:
Note: host reported as
Note: The host is assigned to
Note:
Notes: type host.
[Syns.
Note:
Notes: type host; it was reported as
Note: host reported as
[Syn.
Note: the worms were collected by Palm in Brazil’s Northeastern coast.
Note: metacestode described as
Note:
Note:
Note:
Notes:
Note: host reported as
Notes:
Siluriform fish (
Unidentified ray (
Note:
[For synonyms, see
Note: host reported as
Note: host reported as
Note: type host; it was reported as
[Syn.
Note: host reported as
Note: type host.
[Syns.
Note: type host.
Note: type host.
[Syn.
Note: type host.
Note: tapeworms reported as
Notes:
Note:
Note: type host.
Note: type host.
Note: tapeworms reported as
[Syns.
Note: host reported as
Notes:
Note: host reported as
Note: type host; it was described as
[Syn.
Note: host reported as
Note: type host.
Note: type host.
[Syns.
of infection not given; metacestode; Lima; Peru (
[For synonyms, see
Note: host reported as
serosa, stomach wall; metacestode;
Note: host reported as
Note: host reported as
infection not given; metacestode; Magellanic; Chile, Falkland Islands (
[Syn.
Notes: type host.
[For synonyms, see
Note: tapeworms reported as
Notes: type host.
[Syns.
Note: tapeworms reported as
Note:
[Syns.
Note: host reported as
[Syn.
given; metacestode;
[Syn.
Note: host reported as
[Syn.
[Syns.
Note: the taxonomic status of this species is problematic since the type material is a mixture of different species under the same name (
[For synonyms, see
Note: tapeworms reported as
Note: tapeworms reported as
Note: tapeworms reported as
cavity, muscles; metacestode;
Note: the authors distinguished two different morphotypes.
Note: host reported as
Note:
Notes: host reported as
Note:
Note: host reported as
Note:
[For synonyms, see
Note: type host.
Note: material is deposited in H. Palm’s personal collection.
Note:
Note: host reported as
Note: host reported as
Note:
Note: tapeworms reported as
Note: host reported as
Note: tapeworms reported as
Note: host reported as
Note: host reported as
Note: host reported as
Note: host reported as
Notes:
Note: host reported as
Note: host reported as
Note: host reported as
Note: host reported as 'cação viola', vernacular name of
Note: host reported as 'cação alecrim' vernacular name of
Note: host reported as ‘pescadinha’, vernacular name of sciaenid fishes.
[Syn.
Note:
Note: host reported as
Note:
[Syns.
Notes: host reported as
[Syn.
Note: the type material deposited in
[Syn.
Note: type specimens collected by Olfers are barely recognized as cestodes and basic taxonomic information is missing in the original description; therefore,
Note: hosts reported as
Notes: host collected in a coastal lagoon.
Note: host reported as
Note: introduced fish host (
Notes: host reported as
Notes:
Note: host reported as
Note:
and stage of development not given;
Note: this fish is found only in the Paraíba do Sul and Jequitinhonha River basins (
Note: host reported as
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
unidentified trypanorhynch
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Unidentified siluriform fish
‘
‘
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
Family
The database compiled from the available literature on fish cestodes in South America comprises records of 297 species recognized as valid as well as unidentified ones included in 120 genera and 32 families, associated with 401 cartilaginous and bony fish hosts (Tables
Survey of fish cestodes from South America according to their high taxonomic level classification.
Order | Family | No. of genera | No. of species | Identified to generic level | No. of sequences* |
---|---|---|---|---|---|
|
|
2 | 2 | 0 | 4 |
|
|
4 | 5 | 2 | 12 |
|
2 | 1 | 2 | 4 | |
|
4 | 6 | 1 | 1 | |
|
|
1 | 2 | 0 | 0 |
|
1 | 2 | 1 | 0 | |
|
|
3 | 2 | 1 | 0 |
|
|
3 | 5 | 0 | 12 |
|
|
2 | 3 | 1 | 26 |
|
|
1 | 2 | 0 | 0 |
|
|
1 | 1 | 0 | 0 |
|
1 | 1 | 1 | 0 | |
|
1 | 1 | 0 | 0 | |
|
1 | 1 | 0 | 0 | |
|
1 | 1 | 0 | 0 | |
|
|
4 | 45 | 3 | 3 |
|
1 | 1 | 0 | 0 | |
|
38 | 102 | 15 | 164 | |
|
|
7 | 15 | 2 | 7 |
|
|
1 | 3 | 0 | 6 |
|
2 | 4 | 0 | 0 | |
|
4 | 24 | 2 | 57 | |
‘ |
|
7 | 13 | 1 | 3 |
|
|
5 | 9 | 2 | 2 |
|
1 | 1 | 1 | 0 | |
|
2 | 2 | 1 | 0 | |
|
9 | 16 | 5 | 0 | |
|
2 | 1 | 1 | 0 | |
|
1 | 1 | 0 | 0 | |
|
1 | 4 | 1 | 0 | |
|
1 | 1 | 0 | 0 | |
|
2 | 3 | 1 | 0 | |
|
4 | 17 | 3 | 0 | |
|
|
|
|
|
*Only sequences of cestodes collected in South America were considered.
Survey of fish hosts that harbour cestodes in South America.
Class | Subclass | Order | No. of genera | No. of species | No. of cestodes reported* |
---|---|---|---|---|---|
|
|
|
2 | 2 | 2 |
|
2 | 7 | 4 | ||
|
1 | 1 | 0 | ||
|
2 | 2 | 4 | ||
|
3 | 3 | 0 | ||
|
18 | 27 | 8 | ||
|
8 | 9 | 2 | ||
|
3 | 3 | 1 | ||
|
2 | 4 | 2 | ||
|
9 | 14 | 14 | ||
|
2 | 2 | 0 | ||
|
2 | 3 | 3 | ||
|
1 | 1 | 1 | ||
|
1 | 1 | 2 | ||
|
1 | 2 | 1 | ||
|
1 | 1 | 1 | ||
|
2 | 5 | 11 | ||
|
2 | 4 | 4 | ||
|
1 | 1 | 2 | ||
|
87 | 125 | 46 | ||
|
6 | 9 | 14 | ||
|
3 | 6 | 3 | ||
|
6 | 6 | 3 | ||
|
45 | 68 | 95 | ||
|
7 | 9 | 5 | ||
|
|
8 | 21 | 44 | |
3 | 3 | 8 | |||
4 | 4 | 6 | |||
11 | 33 | 86 | |||
1 | 1 | 2 | |||
8 | 17 | 30 | |||
3 | 2 | 3 | |||
1 | 2 | 2 | |||
2 | 2 | 3 | |||
|
|
1 | 1 | 2 | |
|
|
|
|
*Cestodes with no specific identification were not counted; **Selachii (sharks); ***
The tapeworm with the widest spectrum of definitive hosts is
A total of 208 species of tapeworms are found across seven major ecoregions of South American coast (one additional species is found in Galapagos), being the highest species richness reported from
The geographical distribution of tapeworms in South America associated with their fish hosts from the major marine ecoregions of
The number of taxonomic studies has been steadily growing since 1940, but only 16 papers were based on an integrated taxonomy approach, using molecular data as an important tool. The number of general parasitological surveys has also increased since the beginning of the last century, whereas ecological studies have launched the first publications only in the mid-sixties, with a peak in the last sixteen years, noticeably higher than the previous period (Fig.
Proportion of articles on the fish cestodes from South America published per intervals of years sorted by categories. The numerals above individual bars indicate the absolute number of articles.
Among the genera of fish cestodes reported from South America, one half was either identified only at generic level or they were specifically identified in some reports and at generic level in others. The numerous papers published in the last 30 years, mostly those ecological ones (see Fig.
The accurate identification of larval stages of cestodes is usually challenging, because they lack key morphological traits that are present in their adult forms, and studies dealing with their genetic characterization are rare in South America (
One of the main obstacles that hampers our understanding of the diversity of fish cestodes in South America is the deficient knowledge of their life cycles and failure to match the morphologically amorphous or divergent larval forms to their adult stages; to date, no life cycle studies have been undertaken in this continent.
Unlike the poor taxonomic resolution of marine larvae from teleosts, adult forms, typically those infecting freshwater catfishes (
Contrasting the generally poorly-known diversity of fish cestodes in South America, some groups of hosts have been extensively studied compared to others. Among the elasmobranch hosts, the stingrays (
According to
During the development of this checklist, we have faced several examples of problematic identification and controversial taxonomy of hosts, which may compromise the reliability of any parasitological survey and limit our understanding of host specificity, the relationship between parasite and host phylogenies, as well as the establishment of trophic links elucidated by life-cycle studies (
Therefore, we recommend that parasitologists keep a piece of host tissue in a molecular-grade ethanol for sequencing and to work in synergy with fish taxonomists to be as accurate as possible in fish identification, as already advocated by
The authors are indebted to Roman Kuchta (České Budějovice) for providing helpful comments on the manuscript and Radmila Řepová (České Budějovice) for her help with bibliographic references. Special thanks are extended to Arlene Jones (St. Albans) for revising the English version of the manuscript. This study was supported by the 'Ciência sem fronteiras' Brazilian program visitant researcher modality (No. 135/2012) (stay of TS in Brazil at the