Thelohania montirivulorum sp. nov. (Microspora: Thelohaniidae), a parasite of the Australian freshwater crayfish, Cherax destructor (Decapoda: Parastacidae): fine ultrastructure, molecular characteristics and phylogenetic relationships

Abstract

Thelohania montirivulorum sp. nov., a new species of microsporidian parasite, was found in a highland population of the Australian yabby, Cherax destructor. Data are presented on fine ultrastructure, developmental morphology and DNA sequence of the small subunit ribosomal DNA (SSU rDNA) and internal transcribed spacer region. The phylogenetic relationships of T. montrivulorum sp. nov. and other crayfish parasites in the genus Thelohania, based on the SSU rDNA sequence, are investigated. Fine ultrastructure, patterns of sporogony and SSU rDNA sequence similarities indicate T. montirivulorum sp. nov. is congeneric with T. parastaci, a parasite of lowland populations of C. destructor, and with T. contejeani, a parasite of European freshwater crayfish. SSU rDNA data suggests Thelohania species found in crustacean hosts are more closely related to the Vairimorpha/ Nosema clade of species from insect and crustacean hosts than to the fire ant parasites, T. solenopsae and Thelohania sp.

Thelohania parastaci sp. nov. (Microspora: Thelohaniidae), a parasite of the Australian freshwater crayfish, Cherax destructor (Decapoda: Parastacidae)

“…The issue is unlikely to be resolved until molecular data from other Thelohania species, in particular the type species T. giardi, are available for comparison. SSU rDNA sequence data from this study and others (Lom et al 2001;Moodie et al 2003) indicate that T. parastaci sp. nov. and T. contejeani are more closely related to the Vairimorpha/Nosema group of species than to the fire ant pathogen T. solenopsae (Moser et al 1998), i.e.…”

“…T parastaci sp. nov. was not found in a highland population of C. d. destructor from near Armidale in New South Wales where a different species was detected (Moodie et al 2003). Type specimens of T. parastaci sp.…”

Ultrastructural characteristics and small subunit ribosomal DNA sequence of Vairimorpha cheracis sp. nov., (Microspora: Burenellidae), a parasite of the Australian yabby, Cherax destructor (Decapoda: Parastacidae)

“…nov. were found at very high densities in striated muscle cells in the thorax, abdomen, and appendages of yabbies, often in mixed infections with T. montirivulorum (Moodie et al, 2003b). Where mixed infections occurred, V. cheracis sp.…”

“…nov. (Table 3), were aligned with Clustal X version 1.81 (Jeanmougin et al, 1998). The microsporidian Antonospora scoticae was chosen as the outgroup because of its basal position relative to all other species in trees produced by phylogenetic analyses of a wide range of species from the phylum Microspora (Lom et al, 2001;Moodie et al, 2003b) Phylogenetic analyses were performed with PAUP* version 4.0b9 for Windows (Swofford, 2000), and MrBayes (Huelsenbeck and Ronquist, 2001), on an IBM compatible personal computer (PC). Trees were constructed by PAUP using neighbour-joining distance criteria, maximum parsimony criteria (branch and bound method), maximum likelihood criteria and by Bayesian inference (MrBayes).…”

Prospects for management strategies of invasive crayfish populations with an emphasis on biological control

“…The microsporidian genus Thelohania is polyphyletic; Thelohania spp. infecting crayfish and other crustacean hosts are more closely related to other genera of microsporidia, such as Vairimorpha and Nosema found infecting other Crustacea and insects, than to Thelohania solenopsae from fire ants (Moodie et al, 2003), hence they may have different transmission routes from T. solenopsae in ants.…”