Klossiella (Apicomplexa,Klossiellidae) in Petaurid and Macropodid Marsupials in Australia1

Six new species of Klossiella are described in the kidneys of Australian marsupials: Klossiella rufogrisei in Bennett's Wallaby, Macropus rufogriseus; Klossiella rufi in the Red Kangaroo, Macropus rufus; Klossiella thylogale in the Red-Bellied or Tasmanian Pademelon, Thylogale billardierii; Klossiella beveridgei in the Spectacled Hare-Wallaby, Lagorchestes conspicillatus; Klossiella bettongiae in the Tasmanian Bettong, Bettongia gaimardi; and Klossiella schoinobatis in the petaurid Greater Glider, Petauroides volans. It is concluded that the genus Klossiella has radiated widely among Australian marsupials, and that since it is present in American marsupials, it may have an ancient association with the subclass.     

Klossiella quimrensis (Apicomplexa: Klossiellidae) causes renal coccidiosis in western barred bandicoots Perameles bougainville (Marsupialia: Peramelidae) in Western Australia

Previous studies have described a range of Klossiella species parasitic in marsupial hosts. Klossiella quimrensis is the etiologic agent of renal coccidiosis in the peramelid marsupial hosts Isoodon obesulus and Perameles gunnii in Eastern Australia, but there is no previous report of klossiellosis in Western Australian peramelids. This study describes klossiellosis diagnosed by histology of renal tissue sections collected during necropsy of 20 Perameles bougainville between 2000 and 2005. Sporonts, sporoblasts, and macrogametes were identified within parasitophorous vacuoles of epithelial cells located near the renal corticomedullary junction. The prevalence of renal coccidiosis in P. bougainville diagnosed by renal histology is estimated at 30%. Only a single unsporulated sporocyst was detected by examination of cystocentesis-collected urine, indicating that microscopic evaluation of urine samples is an insensitive diagnostic test for detection of K. quimrensis in P. bougainville. This infection in P. bougainville is indirectly associated with mild multifocal interstitial lymphohistiocytic nephritis and is likely to be only minimally pathogenic in otherwise healthy individuals. Our study also extends the host and geographic range of K. quimrensis to include P. bougainville and Western Australia.     

Novel isotrichid ciliates endosymbiotic in Australian macropodid marsupials

Samples of foregut content were collected from 86 macropodid marsupials and examined for the presence of endosymbiotic ciliates. Four host species were examined: Macropus giganteus (eastern grey kangaroo), M. fuliginosus (western grey kangaroo), M. robustus (common wallaroo) and Thylogale billardierii (Tasmanian pademelon). Ciliate morphology was determined by microscopical examination of live and silver-impregnated specimens. Isotrichid ciliates were detected in 51 (59%) of the 86 animals examined. Five new species and one new genus are described. Three of the species belong to the genus Dasytricha Schuberg, 1888: D. dehorityi n. sp. from M. giganteus, D. dogieli n. sp. from M. robustus and D. mundayi n. sp. from T. billardierii. Bitricha n. g. is characterised by the possession of two fields of somatic ciliation, a transverse ventral and a longitudinal dorsal field. B. oblata n. sp. is described from M. giganteus and M. fuliginosus and B. tasmaniensis n. sp. is described from T. billardierii. The occurrence of isotrichid ciliates in both metatherian and eutherian mammals suggests that the family either evolved prior to the divergence of the mammalian lineages or switched hosts from one group to the other following host diversification.     

Coccidial dispersion across New World marsupials: Klossiella tejerai Scorza,Torrealba & Dagert, 1957 (Apicomplexa: Adeleorina) from the Brazilian common opossum Didelphis aurita (Wied-Neuwied) (Mammalia: Didelphimorphia)

Klossiella tejerai Scorza, Torrealba & Dagert, 1957 is a primitive coccidian parasite reported from the New World marsupials Didelphis marsupialis (Linnaeus) and Marmosa demerarae (Thomas). The current work describes K. tejerai from the Brazilian common opossum Didelphis aurita (Wied-Neuwied) in Southeastern Brazil, evidencing the coccidial dispersion across opossums of the same family. The sporocysts recovered from urine samples were ellipsoidal, 20.4 × 12.7 µm, with sporocyst residuum composed of scattered spherules and c.13 sporozoites per sporocyst, with refractile bodies and nucleus. Macrogametes, microgametes, sporonts, sporoblasts/sporocysts were identified within parasitophorous vacuoles of epithelial cells located near the renal corticomedullary junction. Didelphis marsupialis should not have transmitted K. tejerai to D. aurita because they are not sympatric; however M. demerarae is sympatric with D. marsupialis and D. aurita. Therefore, D. aurita becomes the third host species for K. tejerai in South America.     

Phosphoglycerate kinase pseudogenes in the tammar wallaby and other macropodid marsupials

Phosphoglycerate kinase (EC 2.7.2.3; PGK) exists in two forms in marsupials. PGK1 is an X-linked house-keeping enzyme, and PGK2 is a mainly testis-specific enzyme under autosomal control. We have used PGK1 probes derived from two closely related species of macropodid marsupials (kangaroos and wallabies) to demonstrate the existence of a large family of pseudogenes in the tammar wallaby (Macropus eugenii). Over 30 fragments are detectable after Taq digestion. We estimate that there are 25–30 copies per genome. Most are autosomally inherited and are apparently not closely linked. Only two restriction fragments that appeared to be sex linked could be detected. Varying degrees of hybridization of fragments to the probes suggest different levels of homology, and hence different ages of origin. The existence of two PGK1 homologous restriction fragments from the X and a large number from the autosomes was also demonstrated by somatic cell hybridization for two other macropodid species, the wallaroo (M. robustus) and the red kangaroo (M. rufus). These results are compared with those from human and mouse, and it is suggested that the propensity of PGK1 to form pseudogenes is an ancient (130 MYR BP) characteristic of mammals. The high level of polymorphism detected in the tammar makes these PGK1 probes potentially useful for measuring genetic variability in this species and other macropodids.     

New species of Macropostrongyloides Yamaguti, 1961 (Nematoda: Strongylida) and the redescription of Ma. baylisi (Wood, 1930) from Australian macropodid marsupials

Specimens of four genetically distinct groups of Macropostrongyloides baylisi Wood, 1930 were analysed morphologically. Each genotype was found to represent a morphologically distinct species: Ma. baylisi from Osphranter robustus woodwardi (Thomas) and Osphranter robustus erubescens (Sclater); Ma. spearei n. sp. from Osphranter robustus robustus (Gould) and O. r. erubescens; Ma. mawsonae n. sp. from Macropus giganteus Shaw and Ma. woodi n. sp. from Osphranter rufus (Desmarest). The new species described here are differentiated primarily by several male-specific features that have been overlooked in previous taxonomic revisions. These features include striations on the terminal part of the spicule ala, the papillae surrounding the genital cone and the bursal striations. Furthermore, scanning electron photomicrographs have revealed greater details of previously undefined structures within the buccal cavity that warrant further investigations.

     

Detection by allozyme electrophoresis of cryptic species of Hypodontus macropi (Nematoda: Strongyloidea) from macropodid marsupials.

Allozyme electrophoresis of 98 Hypodontus macropi from eight different species of hosts using 24 enzymes revealed a complex of at least six sibling species, with 15-50% fixed genetic differences between taxa. Except for the taxon parasitizing Macropus rufus/M. robustus, pairs of parasite taxa were, in each case, sympatric at each locality examined, thus supporting the conclusion that they represent valid species. The existence of a series of host-specific nematode taxa explains many of the inconsistencies noted previously in the host distribution of H. macropi. Comparison of parasite allozyme phenograms with host phylogeny suggests that four of the speciation events could be attributable to cospeciation and two to host switching. A clear case of host switching between M. rufus/M. robustus and M. fuliginosus was found.     

A taxonomic revision of Labiostrongylus (Labiostrongylus) (Yorke & Maplestone, 1926) and Labiostrongylus (Labiomultiplex) n. subg. (Nematoda: Cloacinidae) from macropodid and potoroid marsupials

The morphological characters used to differentiate species in the genus Labiostrongylus Yorke & Maplestone, 1926, parasitic in macropodid and potoroid marsupials, are discussed. The genus is divided into three subgenera Labiostrongylus (Labiostrongylus), L. (Labiomultiplex) n. subg. and L. (Labiosimplex) n. subg. on the basis of the presence or absence of interlabia and the morphology of the oesophagus. A key to the subgenera is given and a detailed revision of two of the subgenera is presented. Keys to each of the subgenera are given, the species discussed being: L. (L.) labiostrongylus) (type-species) (syn. L. (L.) insularis, L. (L.) grandis, L. (L.) macropodis sp. inq. and L. (L.) nabarlekensis n. sp., in the subgenus Labiostrongylus, and L. (Lm.) eugenii, L. (Lm.) novaeguineae, L. (Lm.) onychogale, L. (Lm.) uncinatus, L. (Lm.) billardierii n. sp., L. (Lm.) constrictis n. sp., L. (Lm.) kimberleyensis n. sp., L. (Lm.) thylogale n. sp., and L. (Lm.) potoroi, n. sp., in the subgenus Labiomultiplex.     

Foraging behavior of three Tasmanian macropodid marsupials in response to present and historical predation threat

It is often essential to understand historical selection regimes to explain current traits. We studied antipredator behavior of three Tasmanian macropodid marsupials – Forester kangaroos Macropus giganteus , Bennett's wallabies M. rufogriseus , and Tasmanian pademelons Thylogale billardierii – to understand how antipredator behavior functions in a relatively intact predator community. We also compared behavior of the kangaroos and wallabies on a predator-free island where they were translocated from mainland Tasmania 30 yr ago. Both species allowed humans to get closer to them on the predator-free island; a finding consistent with a reduced risk of predation on the island. Neither kangaroos, nor wallabies, exhibited group size effects – they did not modify time allocated to foraging or antipredator vigilance as a function of group size at either site. Nor did overall time allocation vary in any consistent way. In contrast, mainland Australian sibling-species of Forester kangaroos and Bennett's wallabies have both been reported to have group size effects. It is possible either that the extinction of the thylacine Thylacinus cynocephalus in the last century has led to an evolutionary loss of group size effects and other antipredator behavior, or that thylacines were never that important a predator on Tasmanian subspecies. In contrast, Tasmanian pademelons studied on the Tasmanian mainland modified time allocation as a function of group size suggesting that they perceived safety in numbers. Pademelons, because of their body size, are relatively more vulnerable than larger-bodied macropodids to the rich community of marsupial carnivores in Tasmania, and used a mix of social and individual strategies to manage predation risk.     

New species of Wallabinema Beveridge, 1983 (Nematoda: Strongyloidea) and a redescription of W. gallardi (Johnston & Mawson, 1939) from Australian macropodid marsupials

Systematic Parasitology - Two new species of Wallabinema Beveridge, 1983 are described from the sacculated fore-stomachs of macropodid marsupials in Australia. Wallabinema petrogale n. sp. from the...     

An electrophoretic and morphological analysis of Labiostrongylus (Labiosimplex) bancrofti (Johnston & Mawson, 1939) (Nematoda: Cloacinidae), from macropodid marsupials,with the description of two new species

Allozyme electrophoresis was used to compare specimens of Labiostrongylus (Labiosimplex) bancrofti from two species of Australian macropodids, Macropus dorsalis and M. parryi, with a related species, L. (Labiomultiplex) uncinatus which also infests M. dorsalis. Each nematode was characterised genetically at 18 enzyme loci. The level of fixed genetic differences detected between L. (Ls.) bancrofti from M. parryi and M. dorsalis (83%) is equivalent to that when each is compared to the morphologically distinct species L. (Lm.) uncinatus (89–94%), demonstrating unequivocally that the taxon L. (Ls.) bancrofti represents at least two species, one in M. parryi and one in M. dorsalis. In addition, morphological evidence from additional specimens collected from M. parryi suggested the existence of a third sibling species in this group. All three species differ in the shape of the spicule tips; L. (Ls.) bancrofti has longer spicules than either of the two new species. L. (Ls.) quasibancrofti n. sp. has smaller cephalic papillae, larger oesophago-intestinal diverticula, a larger genital cone and a longer female tail than L. (Ls.) turnbulli n. sp. The taxon L. (Ls.) bancrofti consists, therefore, of three species, L. (Ls.) turnbulli in M. parryi, L. (Ls.) quasibancrofti in M. dorsalis, and L. (Ls.) bancrofti found in both host species, as well as in four species of rock wallabies.     

High prevalence of Hepatozoon spp. (Apicomplexa, Hepatozoidae) infection in water pythons (Liasis fuscus) from tropical Australia

Molecular methods were used to identify blood parasites frequently observed in blood smears of water pythons (Liasis fuscus) captured in our study area in the Northern Territory of Australia. A nested polymerase chain reaction (PCR) using primers amplifying the 18s ribosomal RNA (rRNA) nuclear gene resulted in a short PCR product (180 bp) matching this region in the genus Hepatozoon. However, because of the short sequence obtained. 2 new primers were designed based on 18s rRNA sequences of 3 Hepatozoon taxa available in GenBank. Using these primers, approximately 600 bp of the parasite's 18s rRNA gene was amplified successfully and sequenced from 2 water python samples. The new primers were used to investigate the prevalence of blood parasites in 100 pythons. In 25 of these samples we did not observe any blood parasites when examining stained slides. All the samples revealed a 600-bp PCR product, demonstrating that pythons in which we did not visually observe any parasites were infected by Hepatozoon spp. We also analyzed the nucleotide sequences of blood parasites in 4 other reptile taxa commonly encountered in our study area. The sequences obtained from water pythons and from 1 of these taxa were identical, suggesting that the parasite is capable of infecting hosts at different taxonomic levels.     

Effects of water restriction on digestive function in two macropodid marsupials from divergent habitats and the feral goat

The effects of water restriction on digestive function in the euro (Macropus robustus erubescens) found in the arid zone of inland Australia, the eastern wallaroo (M.r.robustus) from more mesic regions of eastern Australia, and the feral goat (Capra hircus) found throughout the range of M. robustus, were compared in order to examine some physiological adaptations required by herbivores for the exploitation of arid environments. Eight animals of each species were held in individual metabolism cages in temperature-moderated rooms and given a chopped hay diet ad libitum. Half the animals were restricted to 40 ml water·kg^-0.80·day^-1. This was 40%, 32% and 57% of voluntary drinking water intake in the euro, wallaroo and goat, respectively. All species responded to water restriction by reducing faecal, urinary and evaporative water losses in association with reductions in feed intake. All animals increased urine osmolality and electrolyte concentrations but not to maximal levels, while packed-cell volume and plasma osmolality and electrolyte concentrations were unaffected by water restriction. The euro displayed a suite of characteristics that separated it from the wallaroo in terms of physiological adaptation, including lower voluntary water intake, an increase in fibre digestibility and maintenance of nitrogen balance during water restriction, and lower faecal water efflux associated with a consistently lower faecal water content (54% versus 59% water in the wallaroo during water restriction, P<0.05). The euro's colon was 37% longer (P<0.01) than that of the wallaroo. The goat had the lowest faecal water efflux (P<0.05) and the longest colon (P<0.001). Water restriction did not affect water content in digesta, nor short-chain fatty acid concentrations or production rates in vitro. Total body water, as a proportion of body mass, was depressed (P<0.05) in the macropodids, but not in the goat. The reduction in dietary nitrogen intake, which accompanied water restriction, was partially compensated by an increase in urea degradation in the gut from 68% to 76% of urea synthesis water-restricted macropodids. These responses to water restriction are discussed in relation to those reported in other macropodid and ruminant species.Abbreviations BM body mass - SCFA short-chain fatty acids - DM dry matter - PCV packed-cell volume     

Identification of zoonotic Giardia genotypes in marsupials in Australia

A total of 421 fecal samples from a variety of captive and wild marsupial hosts in Western Australia, Victoria and South Australia were screened for the presence of Giardia species/genotypes using PCR and sequence analysis of a fragment of the 18S rRNA gene. Giardia spp. were identified in 13.4% (28/209) of samples from captive marsupials and 13.7% (29/212) of samples from wild marsupials. Sequence analysis at the 18S locus identified the zoonotic Giardia duodenalis Genotypes A and B in both captive and wild marsupials. Eight isolates were typed as genotype B3 and B4 at the gdh locus, although 7/8 were typed as genotype A at the 18S rRNA locus. The possible reasons for this discordance are discussed. This is the first report of genotype B and only the second report of genotype A in marsupials. As some of the genotype B isolates were identical to human-derived Giardia gdh sequences, these results suggest that marsupials in catchments may pose a public health risk and therefore warrant further investigation.     

Australiformis semoni (Linstow, 1898) n. gen., n. comb. (Acanthocephala: Moniliformidae) from marsupials of Australia and New Guinea

Australiformis n. gen. is erected for Echinorhynchus (Gigantorhynchus) semoni Linstow, 1898, from Australian and New Guinea marsupials. The new genus differs from Moniliformis and Promoniliformis in lacking spiral muscles in the outer wall of the proboscis receptacle. Linstow's species, E. semoni, is redescribed from abundant material from Peramelidae and Dasyuridae from Australia and New Guinea.     

The taxonomy of Sarcocystis (Protozoa, Apicomplexa) species

The taxonomy of the heteroxenous apicomplexan protozoan genus Sarcocystis was reviewed, and a list of 122 species with their synonyms and hosts given. Both definitive and intermediate hosts are known for only 56 species. The fine structure of the sarcocyst wall may change with age and is not considered necessarily satisfactory for separating species. Specificity for the intermediate host is not narrow for all species. Earlier work on transmission of the parasite from one intermediate host to another should be repeated in the light of present knowledge of the life cycle of species of Sarcocystis.