Redescription of Rugopharynx australis (Mönnig, 1926) and the description of R. moennigi n. sp. (Nematoda: Strongyloidea) from kangaroos (Marsupialia: Macropodidae) in Australia.

Rugopharynx australis (Mönnig, 1926) (Nematoda: Strongyloidea) is redescribed based on specimens from the type host, Osphranter rufus (Desmarest), together with matching DNA sequence data. Additional hosts were Macropus giganteus Shaw and Osphranter robustus (Gould) with single occurrences in M. fuliginosus (Desmarest), Notamacropus dorsalis (Gray), Lagorchestes conspicillatus Gould and Petrogale xanthopus Gray. Rugopharynx moennigi n. sp., formerly included within R. australis, is distinguished by shorter but overlapping spicule lengths and in the morphology of the gubernaculum as well as by molecular data. Rugopharynx moennigi n. sp. appears to be primarily parasitic in M. fuliginosus throughout its geographical range, but also infects M. giganteus, O. robustus and O. rufus in areas of host sympatry.

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.

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

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 rock wallabies Petrogale penicillata (J. Gray) and P. inornata Gould, from Queensland, differs from all congeners in having its four sub-median lips subdivided at the base. Wallabinema macropodis n. sp. from the black stripe wallaby Macropus dorsalis (J. Gray) and the red-necked pademelon Thylogale thetis (Lesson), also from Queensland, is most similar to congeners with the nerve-ring encircling the oesophageal isthmus (W. parvispiculare Beveridge, 1983, W. tasmaniense Beveridge, 1983 and W. thylogale Beveridge, 1983), but differs in the length of the spicules. Wallabinema gallardi (Johnston & Mawson, 1939) is redescribed from T. thetis in Queensland and New South Wales, with T. thetis considered to be the type-host.

Four new species of Rugopharynx Mönnig, 1927 (Nematoda: Strongyloidea) parasitic in the stomachs of macropodid marsupials from Australia.

Four new species of Rugopharynx Mönnig, 1927 are described from macropodid marsupials in Australia, some identified initially using molecular methods. Rugopharynx thetidis n. sp. from Thylogale thetis (Lesson) was initially included within R. sigma Chilton, Beveridge & Andrews, 1993 but was identified as being distinctive using molecular methods and is differentiated morphologically from R. sigma by the more anterior position of the deirid and by the distinctive curvature of the spicule tips. Rugopharynx thylogale n. sp., also from Thylogale thetis, is distinguished by the extreme elongation of the dorsal lobe of the bursa and spicule length (1.07-1.23 mm). Rugopharynx solitarius n. sp., again from Thylogale thetis, was initially included within Rugopharynx zeta (Johnston & Mawson, 1939) but differs morphologically in the features of the bursa. Rugopharynx disiunctus n. sp. from Macropus fuliginosus (Desmarest) was initially included within Rugopharynx rho Beveridge & Chilton, 1999 but was identified as distinctive based on DNA sequence differences. The new species differs from R. rho in the pattern of striations on the buccal capsule and in the lengths of the spicules. Additional records of species of Rugopharyx in M. fuliginosus in Western Australia are provided.

Genetic variation within the genus Macropostrongyloides (Nematoda: Strongyloidea) from Australian macropodid and vombatid marsupials.

The genetic variation and taxonomic status of the four morphologically-defined species of Macropostrongyloides in Australian macropodid and vombatid marsupials were examined using sequence data of the ITS+ region (=first and second internal transcribed spacers, and the 5.8S rRNA gene) of the nuclear ribosomal DNA. The results of the phylogenetic analyses revealed that Ma. baylisi was a species complex consisting of four genetically distinct groups, some of which are host-specific. In addition, Ma. lasiorhini in the common wombat (Vombatus ursinus) did not form a monophyletic clade with Ma. lasiorhini from the southern hairy-nosed wombat (Lasiorhinus latifrons), suggesting the possibility of cryptic (genetically distinct but morphologically similar) species. There was also some genetic divergence between Ma. dissimilis in swamp wallabies (Wallabia bicolor) from different geographical regions. In contrast, there was no genetic divergence among specimens of Ma. yamagutii across its broad geographical range or between host species (i.e. Macropus fuliginosus and M. giganteus). Macropostrongyloides dissimilis represented the sister taxon to Ma. baylisi, Ma. yamagutii and Ma. lasiorhini. Further morphological and molecular studies are required to assess the species complex of Ma. baylisi.

Tziminema unachi n. gen., n. sp. (Nematoda: Strongylidae: Strongylinae) parasite of Baird's tapir Tapirus bairdii from Mexico.

A new genus and species of nematode, Tziminema unachi n. gen., n. sp. is described from the caecum and colon of Baird's tapir Tapirus bairdii (Gill, 1865), found dead in the Reserva de la Biósfera El Triunfo, Chiapas State, in the Neotropical realm of Mexico. Tziminema n. gen. differs from the other nine genera included in the Strongylinae by two main characteristics: having 7-9 posteriorly directed tooth-like structures at the anterior end of the buccal capsule, and the external surface of the buccal capsule being heavily striated. Phylogenetic analyses of the DNA sequences of the mitochondrial cytochrome c oxidase and nuclear DNA, including a partial sequence of the internal transcribed spacer 1, 5.8S and a partial sequence of the internal transcribed spacer 2 of the new taxon, confirmed its inclusion in Strongylinae and its rank as a new genus.

A new species of Kiluluma Skrjabin, 1916 (Nematoda: Strongyloidea) from the white rhinoceros, Ceratotherium simum (Burchell) from South Africa.

A new species of Kiluluma Skrjabin, 1916, Kiluluma ornata n. sp., is described from the intestine of the white rhinoceros Ceratotherium simum (Burchell) from South Africa. The new species is virtually identical with a species described as Kiluluma sp., but not named due to a paucity of material then available. The new species most closely resembles K. solitaria Thapar, 1924 and K. ceratotherii Beveridge & Jabbar, 2013, in the possession of an undulating anterior margin of the buccal capsule but differs in the leaf crown elements which have bulbous, lip-like expansions, which are lacking in K. solitaria and K. ceratotherii.

New species of Cloacina von Linstow, 1898 (Nematoda: Strongyloidea) parasitic in the stomachs of wallaroos, Osphranter spp. (Marsupialia: Macropodidae) from northern Australia.

Three new species of the parasitic nematode genus Cloacina von Linstow, 1898 (Strongyloidea: Cloacininae) are described from the stomachs of wallaroos, Osphranter spp. (Marsupialia: Macropodidae), from northern Australia. Cloacina spearei n. sp. is described from O. robustus woodwardi (Thomas) and O. antilopinus (Gould) and is distinguished from congeners by the shape of the cephalic papillae, the shallow buccal capsule, the presence of an oesophageal denticle and the convoluted but non-recurrent vagina in the female. Cloacina longibursata n. sp. also from O. robustus woodwardi and O. antilopinus is distinguished from congeners by the elongate dorsal lobe of the bursa, with the origin of the lateral branchlets posterior to the principal bifurcation, in the features of the spicule tip, the lack of bosses lining the oesophagus and the absence of an oesophageal denticle. Cloacina crassicaudata n. sp., from the same two host species was formerly identified as C. cornuta (Davey & Wood, 1938). Differences in the cephalic cuticle (inflation lacking in the new species), the shape of the cephalic papillae, the dorsal oesophageal tooth and the spicule tips, as well as differences in the sequences of the internal transcribed spacers of the nuclear ribosomal DNA, indicate that this is an independent species. The geographical distribution of this species is disjunct with populations in both the Northern Territory and Queensland. Possible reasons for the disjunct distribution are discussed.

Density-dependent regulation of fecundity in Syngamus trachea infrapopulations in semi-naturally occurring ring-necked pheasants (Phasianus colchicus) and wild Carrion Crows (Corvus corone).

Previous work has highlighted increased opportunities for the transmission of Syngamus trachea within pheasant release pens, due in part to high levels of environmental contamination around communal areas. Despite this, the distribution of adult worms within their definitive hosts is not significantly different from predicted distributions under Taylor's power law. Therefore, density-dependent processes are probably acting to regulate S. trachea population dynamics. Patterns of nematode fecundity were investigated in a semi-naturally occurring population of ring-necked pheasants (Phasianus colchicus) and a wild population of carrion crows (Corvus carone). Worm length was a reliable indicator of nematode fecundity, and a negative association between mean worm length and mean worm burden was identified within both the species. The stunting of worms at greater parasite densities was present in both immunologically naïve and previously exposed pheasants, so is unlikely to be a function of age-dependent acquired immunity. Interestingly, the effect of parasite crowding in the crow population explained more of the variation in mean worm length, apparently driven by a greater mean worm burden when compared with pheasants. The findings of the present study suggest that fecundity is a function of parasite density, i.e. parasite-mediated competition and not host-mediated heterogeneities in immunocompetence.

New species of Kiluluma Skrjabin, 1916 (Nematoda: Strongylida) from the white rhinoceros Ceratotherium simium (Burchell), with a redescription of K. solitaria Thapar, 1924.

Three species of Kiluluma Skrjabin, 1916 were identified in Ceratotherium simium (Burchell) from a captive population in New South Wales, Australia, based on analysis of the second internal transcribed spacer (ITS-2) of ribosomal DNA. One species was identified as K. solitaria Thapar, 1924 and is redescribed. A second species is new and is described here as K. ceratotherii n. sp. The third species is new but was represented by two individuals only and is described but is not named.

Fecundity of various species of strongylids (Nematoda: Strongylidae)--parasites of domestic horses.

The aims of the study were to determine fecundity of several strongylid species parasitizing domestic horses and analyze possible relations between numbers of eggs in female uteri and size of both the eggs and the nematodes as well as the influence of fecundity on proportion of species in the strongylid community. Twenty-five specimens from each of 15 strongylid species (Strongylus vulgaris, Strongylus edentatus, Triodontophorus serratus, Triodontophorus brevicauda, Triodontophorus tenuicollis, Cyathostomum catinatum, Coronocyclus coronatus, Cylicocyclus nassatus, Cylicocyclus insigne, Cylicocyclus leptostomus, Cylicostephanus calicatus, Cylicostephanus goldi, Cylicostephanus longibursatus, Cylicostephanus minutus, and Poteriostomum imparidentatum) collected after necropsy were studied. The reproductive system was extracted from the female body; all eggs were removed, counted, and measured under a light microscope. Significant differences in number of eggs in female uteri of various strongylid species were observed (Kruskal-Wallis test, p < 0.001); the least numbers of eggs were registered in C. longibursatus (average = 49) and C. leptostomus (63) and the largest number in S. edentatus (5,918). Significant correlation between nematode body size and number of eggs was observed (p < 0.001). Correlation between size of eggs and body size was insignificant (Spearman R = 0.11, p = 0.70). Negative correlation was observed between number of eggs in female uteri and proportion of these species in strongylid community (Spearman R = -0.78, p < 0.001). Multiple linear regression of species proportion in the community on three predictors (number of eggs, body size, and egg size) was not significant (p > 0.05). However, the question on influence of fecundity on proportion of species in strongylid community needs further studies.

Three recently recognized species of cyathostomes (Nematoda: Strongylidae) in equids in Kentucky.

Three species of cyathostomes--Cylicocyclus ashworthi, Cylicostephanus bidentatus, and Cylicostephanus hybridus were identified recently in horses in Kentucky. General characteristics and distinguishing description of these species are presented. Distribution of these species and their role in the horse strongylid community are discussed. The importance of examining the entire contents of the large intestine or alternatively a high number of specimens in order to recover and identify species residing in low numbers is stressed.

GAPEWORM (SYNGAMUS SPP.) PREVALENCE IN WISCONSIN GREATER PRAIRIE CHICKENS (TYMPANUCHUS CUPIDO PINNATUS).

Under Wisconsin state law, the greater prairie chicken (GRPC; Tympanuchus cupido pinnatus) has been listed as a threatened species since 1976. In 2014-15, we conducted a pilot study to determine the prevalence and intensity of gapeworms (Syngamus spp.) in female Wisconsin GRPCs collected from 2 monitored populations. We captured 62 female GRPCs using walk-in-style traps for females and night lighting for juveniles ≥45 days of age. From these individuals, we collected 15 carcasses of radio-marked birds, most of whom died due to predation events. Through dissection, we identified gapeworm in 20% of examined carcasses and report an intensity ranging between 4 and 74 worms.

Morphology and diagnosis of the fourth-stage larva of Coronocyclus labratus (Looss, 1900) (Nematoda: Strongyloidea) parasitising equids.

The fourth larval stage (L4) of Coronocyclus labratus (Looss, 1900) Hartwich, 1986, one of the common species of the Cyathostominae found in equids, is identified and described. The larvae found were identified as C. labratus by finding moulting forms possessing characters of both larval and adult stages. The larvae are similar to those of Cylicocyclus leptostomum (Kotlán, 1920) Foster, 1936, Cyathostomum catinatum Looss, 1900 and Cylicostephanus goldi (Boulenger, 1917) Lichtenfels, 1975. The buccal capsule (BC) wall of the L4 of Cylicocyclus leptostomum is thinner than that of Coronocyclus labratus, and the ring of the oesophageal funnel is comparatively less well developed. In C. labratus the dorsal tooth protrudes only slightly into the buccal cavity, and this larva possesses a characteristically elongate, pyriform oesophagus. In Cyathostomum catinatum, the BC walls are thicker than in Coronocyclus labratus, and the dorsal tooth is more bluntly pointed. Sublateral teeth, if present, are bluntly pointed in the former species, but usually absent or indistinct in C. labratus. Larvae of Cylicostephanus goldi differ from those of Coronocyclus labratus in the larger size of the BC.

Illustrated identification keys to strongylid parasites (Strongylidae: Nematoda) of horses, zebras and asses (Equidae).

The Equidae (the horse, Equus caballus, the ass, Equus asinus, zebras and their hybrids) are hosts to a great variety of nematode parasites, some of which can cause significant morbidity or mortality if individual hosts are untreated. Worldwide the nematode parasites of horses belong to 7 suborders, 12 families, 29 genera and 83 species. The great majority (19 of 29 genera and 64 of 83 species) are members of the family Strongylidae, which includes the most common and pathogenic nematode parasites of horses. Only the Strongylidae are included in this treatise. The Strongylidae (common name strongylids) of horses--nematodes with a well-developed buccal capsule, a mouth collar with two leaf-crowns, and a strongyloid (common name of superfamily Strongyloidea) copulatory bursa--can be separated into two subfamilies: Strongylinae (common name strongylins), usually large or medium-sized with a globular or funnel-shaped buccal capsule; and Cyathostominae (common name cyathostomins), usually small to medium-sized with a cylindrical buccal capsule. The increased attention to strongylid nematode parasites of horses has resulted in the need for updated diagnostic keys to these parasites using readily recognizable characters and the most recent literature on their systematics. Because the cyathostomins have been historically difficult to identify, and because they have emerged as the most significant nematode pathogens of horses, we provide a brief nomenclatural and taxonomic history and an introduction to the morphology of this group. This treatise is intended to serve as a basic working tool--providing easy identifications to genus and species of adult strongylid nematodes of equids. All strongylid nematodes normally parasitic in horses, the ass (and their hybrids), and zebras are included. The keys are illustrated with line drawings and halftone photomicrographs of each species. A short discussion of the systematics of the genus and species is provided for each genus following the species descriptions. Species diagnoses and a synonymy of each species is provided. Geographic distribution, prevalence, and location in host are also given for each species.

Description of a new species of Rhabdias Stiles and Hassall, 1905 (Nematoda: Rhabdiasidae) from Western Himalayan foothills (Uttarakhand), India.

Rhabdias garhwalensis sp. nov. from the lungs of Duttaphrynus himalayanus (Günther, 1864) collected in Kimoi Tehsil, district Tehri Garhwal (Uttarakhand), India is described and illustrated. Rhabdias garhwalensis sp. nov. represents the 15th species described from the Oriental zoogeographical zone and the 9th species from India. The new species is differentiated from the closely related Oriental species in having 6 lips, cup-shaped buccal cavity with muscular striations in the posterior region and smaller esophagus to body length ratio. In addition to the new species, a second species, Cosmocercoides bufonis Karve, 1944, was found in the large intestine of D. himalayanus.

An electrophoretic analysis of patterns of speciation in Cloacina clarkae, C. communis, C. petrogale and C. similis (Nematoda:Strongyloidea) from macropodid marsupials.

An electrophoretic study was conducted on Cloacina clarkae, C. communis, C. petrogale and C. similis based on 19 enzyme loci. C. communis was widely distributed in Macropus robustus, showing some genetic variation among populations but occasionally switching to other macropodid hosts (M. agilis, M. antilopinus). C. similis occurred in members of the Petrogale penicillata complex, Macropus dorsalis and Thylogale billardierii, but showed no evidence of genetic differentiation in spite of its occurrence in different host species and in geographically distinct regions of Australia. C. clarkae from Macropus eugenii was genetically indistinguishable from C. similis and was considered synonymous with it. C. petrogale occurred in a similarly diverse range of hosts and geographical regions to C. similis, but was represented electrophoretically as 4 distinct genetic species, 1 in Petrogale assimilis, a second in P. lateralis purpureicollis, a third in Macropus parryi in Queensland and a fourth in M. eugenii in South Australia. Although the host and geographical ranges of C. similis and C. petrogale are analogous, the genetic uniformity of the former and diversity of the latter illustrate the incomplete understanding we have of the immediate causes of speciation in nematodes.

Phylogenetic relationships of Australian strongyloid nematodes inferred from ribosomal DNA sequence data.

The sequence of the second internal transcribed spacer of the ribosomal DNA was determined for the following strongyloid nematodes: Cylicocyclus insignis, Chabertia ovina, Oesophagostomum venulosum, Cloacina communis, Cloacina hydriformis, Labiostrongylus labiostrongylus, Parazoniolaimus collaris, Macropostrongylus macropostrongylus, Macropostrongylus yorkei, Rugopharynx australis, Rugopharynx rosemariae, Macropostrongyloides baylisi, Oesophagostomoides longispicularis and Paramacropostrongylus toraliformis, and compared with published sequences for species of Strongylus and for Hypodontus macropi. The resultant phylogenetic trees supported current hypotheses based on morphological evidence for the separation of the families Strongylidae and Chabertiidae, but did not support the separation of the endemic Australian genera as a distinctive clade within the Chabertiidae. The implications of this finding for the phylogenetic origins of the Australian strongyloids are discussed.

Evidence for hybridisation between Paramacropostrongylus iugalis and P. typicus (Nematoda:Strongyloidea) in grey kangaroos, Macropus fuliginosus and M. giganteus, in a zone of sympatry in eastern Australia.

Specimens of Paramacropostrongylus iugalis and P. typicus, collected from eastern (Macropus giganteus) and western (M. fuliginosus) grey kangaroos in New South Wales and Queensland, were examined morphologically and electrophoretically at 4 enzyme loci previously demonstrated to be diagnostic between the 2 species. Collections of P. iugalis from M. giganteus from outside the zone of sympatry of the 2 kangaroo species conformed electrophoretically and morphologically with previous studies. Within the zone of sympatry, the 2 nematode species were distinguishable electrophoretically, with most P. iugalis occurring in M. giganteus and all P. typicus occurring in M. fuliginosus. Some specimens of P. iugalis were identified in M. fuliginosus and, in both host species, nematodes were encountered with electrophoretic profiles intermediate between P. iugalis and P. typicus. The frequent occurrence in these specimens of heterozygotes suggested that the genetic barriers between the 2 nematode species were not complete and that genetic interchange (i.e. hybridisation) was occurring.

Sibling species within Macropostrongyloides baylisi (Nematoda: Strongyloidea) from macropodid marsupials.

Macropostrongyloides baylisi from four different species or subspecies of host were analysed electrophoretically at 27 enzyme loci. The results revealed the existence of two species, one in Macropus giganteus and the other in M. robustus robustus, M.r. erubescens and M.r. parryi, that had fixed genetic differences at 33% of loci. Populations of nematodes from two subspecies of M. robustus, M.r. robustus from Queensland and M.r. erubescens from South Australia, had fixed genetic differences at two (7.4%) of 27 loci and were considered to belong to the same species. No fixed genetic differences were detected between nematodes from M. parryi and M.r. robustus. A discriminant function analysis of morphological data assigned 96% of specimens to groups defined on the basis of the host species or subspecies from which they were obtained. This separation of Ma. baylisi into host-specific groups did not, however, totally correlate with the electrophoretic data. The species of M. baylisi in M. giganteus was genetically more distinct from the sibling species in M. robustus/M. parryi than to a related but morphologically dissimilar nematode, Ma. yamagutii from M. fuliginosus. This suggests an evolutionary parallel between host and parasite at the genetic level which is not reflected by morphological differences.