Interbreeding in the subfamily Ostertagiinae (Nematoda: Trichostrongylidae) of ruminants.

The interbreeding of 6 species of ostertagiines was studied in a sheep model. Virgin young females of selected nonpolymorphic strains of Ostertagia ostertagi, Ostertagia leptospicularis, and Teladorsagia circumcincta were mated with various male ostertagiines. Interbreeding was successful between O. ostertagi and Ostertagia lyrata, O. leptospicularis and Ostertagia kolchida, and T. circumcincta and Teladorsagia trifurcata, respectively. Their offspring were fertile and resembled one parent or the other without intermediate forms: each pair is a polymorphic species. Infertile hybrids, intermediate in form, were obtained from interbreeding between O. ostertagi and O. leptospicularis and they remain valid species.     

Synlophe patterns of the Haemonchinae of ruminants (Nematoda: Trichostrongyloidea)

The pattern of longitudinal ridges (synlophe) on the external cuticular surface of trichostrongylid nematodes has been shown to be of value for distinguishing species and determining relationships among higher taxa. In the process of studying Mecistocirrus digitatus, the large stomach worm of bovids of Asia that has been imported and established in the Americas, we observed remarkably similar synlophe patterns to those described for 3 species of Haemonchus and to those we examined in a species of Ashworthius. In all 3 genera, the synlophe is absent from the posterior part of the body. Only in Haemonchus does the synlophe extend beyond midbody. In both M. digitatus and Ashworthius sidemi, the synlophe extends posteriorly only about 1/4 of body length. In all 3 genera, the synlophe consists of about 30 ridges in the region of the esophagus with variation among species in specific areas, including additional pairs of subventral and subdorsal ridges and different lengths of sublateral ridges. This information is useful for identifying species and determining relationships among these large stomach worm parasites of cattle, sheep, goats, and farmed and wild cervids.     

New species of Oswaldocruzia (Nematoda: Molineoidae), new species of Rhabdias (Nematoda: Rhabdiasidae), and other helminths in Rana cf. forreri (Anura: Ranidae) from Costa Rica

Oswaldocruzia costaricensis n. sp. (Strongylida: Molineidae) from the intestines and Rhabdias savagei n. sp. (Rhabditida: Rhabdiasidae) from the lungs of Rana cf. forreri (Anura: Ranidae) are described and illustrated. Oswaldocruzia costaricensis represents the 77th species assigned to the genus and differs from the other Neotropical species in the genus by possessing a Type II bursa and long cervical alae. Rhabdias savagei represents the 47th species assigned to the genus and differs from other Neotropical species in the genus by possession of 4 lips and a postequatorial vulva. Rana cf. forreri was also found to harbor the trematodes, Haematoloechus parcivitellarius and Megalodiscus temperatus, the nematodes, Aplectana incerta, Aplectana itzocanensis, Cosmocerca podicipinus, Foleyellides striatus, Subulascaris falcaustriformis, and a larva of the nematode Brevimulticaecum sp. Cosmocerca panamaensis is considered to be a synonym of Cosmocerca podicipinus.     

Distribution and ecology of meningeal worm,Parelaphostrongylus tenuis (Nematoda), in northcentral North America

Meningeal worm (Parelaphostrongylus tenuis), a common nematode parasite in white-tailed deer (Odocoileus virginianus) and pathogenic for several species of ungulates in eastern North America, is not known to occur in the west. Heads of 1,902 white-tailed deer were examined for adult meningeal worm to determine geographic distribution of the parasite in Saskatchewan and Manitoba (Canada) and North Dakota (USA). Finding the parasite in a deer in eastern Saskatchewan near the Manitoba border established the current northern and western limits in Canada. Prevalence of infection was < 1, 18.6, and 8.2% in Saskatchewan, Manitoba, and North Dakota, respectively. Infected deer occurred throughout southern Manitoba and eastern North Dakota. Distribution appears to have changed little since the last published survey for P. tenuis in the region in 1972. We examined precipitation, temperature, deer density, and forest cover as likely correlates to prevalence and distribution of P. tenuis. Deer management units used for hunting purposes were the scale of analysis in the three jurisdictions. Presence of P. tenuis was positively correlated with precipitation during frost-free periods and deer density, and it was negatively correlated with winter and spring temperatures. Landscapes with > 25 and < 75% forest cover were most likely to have infected deer. Low rainfall and low density of white-tailed deer likely influence the westernmost limit of P. tenuis.     

Distribution of the monarch butterfly, Danaus plexippus (L.) (Lepidoptera: Nymphalidae), in western North America

The standard model for the migration of the monarch butterfly in western North America has hitherto been movement in the autumn to overwintering sites in coastal California, followed by a return inland by most individuals in the spring. This model is based largely on observational and limited tagging and recovery data. In this paper we test the model by plotting many years of museum and collection records on a monthly basis on a map of the region. Our plots suggest a movement of Oregon, Washington and other north-western populations of summer butterflies to California in the autumn, but movement of more north-easterly populations (e.g. from Idaho and Montana) along two pathways through Nevada, Utah and Arizona to Mexico. The more westerly of these two pathways may follow the Colorado River south as indicated by museum records and seasonal temperature data. The eastern pathway may enter northern Utah along the western scarp of the Wasatch Mountains and run south through Utah and Arizona. Further analysis of distributions suggests that monarch butterflies in the American West occur primarily along rivers, and there are observations indicating that autumn migrants often follow riparian corridors. More data are needed to test our new model; we suggest the nature of the data required.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 491–500.     

Dermacarus jonesi sp. n. (acari: Labidophorinae: Glycyphagidae) from Peromyscus maniculatus from western North America.

A new species of labidophorine hypopus, Dermacarus jonesi, is described from Peromyscus maniculatus from Washington, USA, and British Columbia, Canada. A single individual was also found on Sorex sp. from California.     

Diversity of late Maastrichtian Tyrannosauridae (Dinosauria: Theropoda) from western North America

The tooth taxon Aublysodon mirandus was reinstated following the collection of nondenticulate tyrannosaurid premaxillary teeth from late Maastrichtian deposits in western North America. A small skull from the Hell Creek Formation of Montana (the 'Jordan theropod', LACM 28471), that was associated with a nondenticulate premaxillary tooth, was referred to Aublysodon and the diagnosis was revised to include cranial bones. However, the 'premaxillary' tooth of the specimen is actually a maxillary tooth. The small size of Aublysodon crowns, and evidence that some denticles develop late in growth in theropods, indicates that the nondenticulate condition represents immaturity. Therefore, Aublysodon is a nomen dubium. The Jordan theropod was recently designated as the type specimen of Stygivenator molnari . A tyrannosaurid from the Hell Creek Formation of Montana (LACM 23845) was first referred to Albertosaurus cf. A. lancensis and then later became the type specimen of Dinotyrannus megagracilis . On the basis of shared derived characters and a quantitative reconstruction of the growth series of Tyrannosaurus rex , the type specimens of S. molnari and D. megagracilis are juvenile and subadult specimens of T. rex , respectively. There is currently evidence for only one tyrannosaurid species in the late Maastrichtian of western North America: T. rex .  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 142 , 479–523.     

Two new species of Cymopterus (Umbelliferae) from western North America

Two species ofCymopterus are described as new:Cymopterus douglassi from the Lost River and Lemhi ranges of central Idaho and the closely relatedC. williamsii from the southern half of the Big Horn Mountains, Wyoming. Both are diploid on the basex=11 and occur on calcareous or dolomitic substrates. The mature fruit ofCymopterus williamsii differ from those ofC. douglassii in the absence of a functioning carpophore and in having 1, not 3–5 oil tubes in the intervals. Both species are unusual in the genus, though not unique, in that the dorsal ribs of the mericarps are not winged.     

DNA evidence that Ostertagia gruehneri and Ostertagia arctica (Nematoda: ostertagiinae) in reindeer from Norway and Svalbard are conspecific

DNA sequences of ITS-1 and ITS-2 of rDNA were determined for 16 individual adult males each of Ostertagia gruehneri and Ostertagia arctica from Svalbard reindeer (Rangifer tarandus platyrhynchus) and Eurasian tundra reindeer (R. t. tarandus). Each ITS was virtually identical in O. gruehneri and O. arctica and the three mixed bases detected were shared by both species. Our results strongly suggest that O. gruehneri and O. arctica are dimorphic males of the same species.     

Aspidoderidae from North America, with the description of a new species of Aspidodera (Nematoda: Heterakoidea)

Aspidodera sogandaresi n. sp. (Heterakoidea: Aspidoderidae) from Dasypus novemcinctus Linnaeus, 1758 is herein described. This nematode occurs in armadillos from as far south as the canal zone of Panama, north through central Mexico, and into the southern United States. Previously identified as Aspidodera fasciata (Schneider, 1866), this new species has blunt projections on the lips and lateral expansions at the distal tips of the spicules, whereas A. fasciata has conspicuous digitiform projections on the lips, and a terminal round expansion at the tips of the spicules. Other species of the family present in North America include Aspidodera binansata Railliet and Henry, 1913; Aspidodera vazi Proen?a, 1937; and Lauroia trinidadensis Cameron, 1939.     

Pseudostertagia bullosa (Nematoda: Trichostrongyloidea) in artiodactyl hosts from North America: redescription and comments on systematics

A relationship for Pseudostertagia bullosa within the trichostrongyloids has been enigmatic or unresolved. Studies of the synlophe in males and females of P. bullosa revealed a tapering system anterior to the deirids and a pattern of parallel ridges extending to near the caudal extremity in both lateral and median fields. Structurally, the synlophe differs considerably from that seen among the Cooperiinae and exhibits homoplasy with respect to ridge systems among some Ostertagiinae. Other structural characters due to symplesiomorphy, homoplasy or because they represent autapomorphies do not serve to reveal the putative relationships for P. bullosa with other trichostrongyloids. Although somewhat equivocal, the 2-2-1 pattern of the bursa and position of rays 2 and 3 suggest an association with the Cooperinae, as postulated by Durette-Desset and others. Pseudostertagia bullosa appears to be a species that has survived in the pronghorn, Antilocapra americana, a relictual pecoran artiodactyl that occurs in xeric regions of western North America; pronghorn are the sole remnant of the late Tertiary radiation for Antilocapridae across North America. Pseudostertagia bullosa may occur in mixed infections with a number of ostertagiines in the abomasa of mule deer (Odocoileus hemionus) and domestic sheep (Ovis aries) in regions of sympatry for pronghorn and these artiodactyl hosts.     

New species of Ostertagia sogdiana sp. n. (Nematoda, Trichostrongylidae) from the domestic goat in Uzbekistan

In the abomasum of domestic goat of Uzbecistan there were found ostertagiae which differ distinctly from earlier described species of the family Trichostrongylidae in size and structure of spicules and in the morphology of genital conus. The new species Ostertagia sogdiana sp. n. (fam. Trichostrongylidae) is described.     

Similarities between species of the Ostertagiinae (Nematoda: Trichostrongyloidea) in relation to host-specificity and climatic environment

Multivariate analyses of similarities between species of the Ostertagiinae were performed on the data from 585 publications. The environmental factors were 12 climates and host-specificity in ruminants (40 species) for 16 species of ostertagiines. This approach can be a useful tool for distinguishing morphs from species. The following pairs (species and its possible morph) of ostertagiines are proposed: Ostertagia ostertagi — O. lyrata, O. leptospicularis — O. kolchida, O. gruehneri — O. arctica, Teladorsagia circumcincta — T. trifurcata, Marshallagia marshalli — M. occidentalis, Spiculopteragia boehmi — S. mathevossiani, and S. asymmetrica — S. quadrispiculata.