Trypanosomes infecting cod Gadus morhua L. in the North Atlantic: a resurrection of Trypanosoma pleuronectidium Robertson, 1906 and delimitation of T. murmanense Nikitin, 1927 (emend.), with a review of other trypanosomes from North Atlantic and Mediterranean teleosts

Abstract

Trypanosomes were isolated from Atlantic cod Gadus morhua L. collected from several fjords in western Norway. Morphological studies showed that the 12 infections studied represented a single species, identified as Trypanosoma pleuronectidium Robertson, 1906 which is resurrected and redescribed. This species is characterised by its body length (57.9 +/- 5.4 microm), nearly central nucleus (NI = 1.05 +/- 0.12) and relatively short post-kinetoplastic (PK) region (3.2 +/- 0.8 microm). T. pleuronectidium is transmitted by the leech Calliobdella nodulifera (Malm). T. murmanense Nikitin, 1927 (emend.) is delimited to a species transmitted by the leech Johanssonia arctica (Johansson). This species is separated from T. pleuronectidium by its attained body length, more anterior nucleus, presence of cytoplasmic refractive granules, adnuclear vacuoles and by a longer PK region. Partial SSU rDNA sequences of T. pleuronectidium and T. murmanense from Norway (1980 nt) diverged by 1.9%. The nominal North Atlantic and Mediterranean trypanosome species are reviewed, and T. flesi Lebailly, 1904, T. bothi Lebailly, 1905 and T. limandae Brumpt & Lebailly, 1904 are considered synonyms of T. platessae Lebailly, 1904. T. triglae senegalensis Ranque, 1973 is not considered conspecific with T. triglae Neumann, 1909, and consequently raised to species status as T. senegalense Ranque, 1973. Some other likely synonymies are discussed. In addition to T. pleuronectidium and T. murmanense, the following marine teleost trypanosomes are provisionally listed as valid species pending further study: T. callionymi Brumpt & Lebailly, 1904; T. cotti Brumpt & Lebailly, 1904; T. delagei Brumpt & Lebailly, 1904; T. dorhni Yakimov, 1911; T. gobii Brumpt & Lebailly, 1904; T. laternae Lebailly, 1904; T. myoxocephali Fantham, Porter & Richardson, 1942; T. platessae Lebailly, 1904; T. scorpaenae Neumann, 1909; T. soleae Laveran & Mesnil, 1901; T. triglae Neumann, 1909; and T. yakimovi Yakimov, 1911.

Haematological response of snow barbell, Schizothorax plagiostomus Heckel, naturally infected with a new Trypanosoma species

“…The important morphological characters at the light microscopical level that are useful to distinguish different species include; size, PK region extent, position of nucleus (i.e. NI), and flagellar-lengths (Diamond 1965;Hoare 1972;Gupta 2006;Karlsbakk and Nylund 2006). Various dimorphic trypanosome species have been reported from around the world including India.…”

Morphological and genetic differences of Trypanosoma in some Chinese freshwater fishes: difficulties of species identification

“…Obviously, there is a need for a redescription of most the "old" nominal trypanosome species based on character variation and molecular data. The lack of knowledge on leech taxonomy and ecology probably also causes these problems, as fish trypanosomes maybe specific to their leech host (Karlsbakk 2004;Karlsbakk and Nylund 2006;Khaibulaev 1970). So far, no leeches have been found on Chinese fishes with trypanosomes, excepting that of Batracobdella paludosa Carena, which was identified as a vector of T. lichuanensis (Li and Wang 1996).…”

“…Recently, molecular methods such as random amplification of polymorphic DNA and analysis of the ribosomal DNA sequences have been effectively applied to taxonomic issues involving fish trypanosomes (Figueroa et al 1999;Davies et al 2005;Gibson et al 2005; Karlsbakk and Nylund 2006;Gu et al 2007). Especially, the use of SSU rRNA gene sequences in combination with morphological data greatly promotes the correct species identification and infers phylogenetic relationships within fish trypanosomes (Davies et al 2005;Karlsbakk and Nylund 2006;Gu et al 2007).…”

“…Especially, the use of SSU rRNA gene sequences in combination with morphological data greatly promotes the correct species identification and infers phylogenetic relationships within fish trypanosomes (Davies et al 2005;Karlsbakk and Nylund 2006;Gu et al 2007). For example, analyses of 18S rRNA gene sequence showed that fish trypanosomes with similar morphology from Botswana at least have two genotypic groups (Davies et al 2005).…”

Trypanosomatids (Protozoa: Kinetoplastida) in three species of Armored Catfish from Mogi-Guaçu river, Pirassununga, São Paulo, Brazil

“…Molecular techniques have been showed as more effective when applied toward the taxonomic determinations to identification of trypanosomes (FIGUEROA et al, 1999;KARLSBAKK & NYLUND, 2006;GU et al, 2007a, b).…”