Two new species of Rhabdias (Nematoda: Rhabdiasidae) from the marine toad, Bufo marinus (L.) (Lissamphibia: Anura: Bufonidae), in Central America

Two new Rhabdias species are described from the lungs of the cane toad Bufo marinus (L.) from Costa Rica and Nicaragua. Rhabdias alabialis n. sp. differs from other known species of the genus by the remarkable morphology of its head end, i.e., the absence of lips or pseudolabia, the slitlike oral opening, and the triangular shape of the buccal capsule in apical view. Rhabdias pseudosphaerocephala n. sp. is identified as a form previously known in Central and South America as Rhabdias sphaerocephala Goodey, 1924, a species initially described from toads in Europe. The new species is differentiated from R. sphaerocephala based on head-end morphology and sequences of nuclear rDNA.     

A new rhabdiasid species from Norops megapholidotus (Sauria: Polychrotidae) from Mexico

Rhabdias leonae n. sp., a parasite of the lungs of Norops megapholidotus, is described and illustrated. The Mexican taxon differs from the other species in the genus by a combination of characters: possession of 4 lips, corpus slightly inflated, slightly postequatorial vulva, and presence of swollen cuticle of anterior and posterior ends. This is the 12th species described in the Neotropical realm and the first species of Rhabdias described from an endemic Mexican lizard.     

New species of Rhabdias (Nematoda: Rhabdiasidae) and other helminths from Norops capito (Sauria: Polychrotidae) from Nicaragua

Rhabdias nicaraguensis n. sp. (Rhabditida: Rhabditidae) from the lungs of Norops capito (Sauria: Polychrotidae) is described and illustrated. Rhabdias nicaraguensis n. sp. represents the 54th species assigned to the genus and the 12th from the Neotropical realm. Of the 12 Neotropical Rhabdias species, nicaraguensis is most similar to tobagoensis and vellardi. These 3 species have equatorial placement of the vulva, inflated cuticle, and 6 small circumoral lips. Rhabdias nicaraguensis is easily separated from R. tobagoensis by the shape of the buccal cavity and from R. vellardi by body size and shape of the tail. Rhabdias nicaraguensis differs from both species by host preference, the amount of inflated cuticle covering the body, and the phasmids situated posterior to the midpoint of the tail.     

Rhabdias paraensis sp. nov.: a parasite of the lungs of Rhinella marina (Amphibia: Bufonidae) from Brazilian Amazonia

The nematode parasites of Rhinella marina include species of the genus Rhabdias (Rhabdiasidae: Rhabditoidea). The present study describes Rhabdias paraensis sp. nov., which parasitizes the lungs of R. marina in Brazilian Amazonia. Of the more than 70 known species of this genus, 18 are parasites of bufonids, of which, eight are Neotropical. The new species described here is similar to Rhabdias alabialis in the absence of lips is different by the presence of conspicuous cephalic papillae. We describe details of the four rows of pores, which are distributed equally along the whole of the length of the body and connected with hypodermal cells, using histology and scanning electron microscopy. Other histological aspects of the internal structure of this nematode are also described.     

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.     

<Emphasis Type="Italic">Rhabdias lacertae</Emphasis> n. sp. (Nematoda: Rhabdiasidae), the first rhabdiasid species parasitising lizards in Europe

A new nematode species, Rhabdias lacertae n. sp. (Rhabdiasidae), is described from the body-cavity of the common lizard Lacerta vivipara Jacquin (Lacertidae) from the Ridge of Malá Fatra (Sokolie Hill), north-western Slovakia. The new species differs from its congeners mainly in possessing 3 min cuticular spikes at the tail tip and some other features. This is the first species of Rhabdias Stiles & Hassall, 1905 described from lizards in Europe and the first species of this genus parasitising hosts belonging to the Lacertidae.     

New species of Rhabdias (Nematoda: Rhabdiasidae) from Bufo occidentalis (Anura: Bufonidae) from Sierra Madre del Sur, Mexico

Rhabdias kuzmini n. sp., a parasite of the lungs of Bufo occidentalis, is described and illustrated. This Mexican taxon differs from the related species in the genus by the possession of 4 lips (2 subdorsal and 2 subventral) and 2 lateral pseudolabia, corpus not inflated, a larger barrel-shaped buccal capsule, equatorial vulva, and the presence of a slightly swollen cuticle in the anterior and posterior ends of the body. This is the 16th species described in the Neotropical Realm and the first species of Rhabdias described from endemic anurans in México.     

The host preferences of Nuttalliella namaqua (Ixodoidea: Nuttalliellidae): a generalist approach to surviving multiple host-switches

Nuttalliella namaqua has been described as a “living fossil” and the closest extant species to the ancestral tick lineage. It was previously proposed that the Nuttalliella lineage parasitized reptile-like mammals in the Permian and had to switch hosts several times due to mass or host lineage extinctions. Extant hosts include girdled lizards and murid rodents. The current study extends knowledge on the extant host range of N. namaqua using gut meal analysis of field collected specimens. Nymphs and females can parasitize a variety of reptiles that includes skinks, geckos and girdled lizards. Blood-meal from a hyrax was also detected in a specimen suggesting that N. namaqua could parasitize a broader range of mammals than the previously suggested murid rodents. Rather than being host specific, N. namaqua is proposed to be a generalist and the ability to switch and parasitize multiple hosts allowed it to survive multiple mass and host lineage extinctions.     

Rhabdias anolis n. sp. (Nematoda: Rhabdiasidae) from the lizard,Anolis frenatus (Sauria: Polychrotidae), from Panama

Rhabdias anolis n. sp. from the lungs of Anolis frenatus collected in Panama is described and illustrated. Rhabdias anolis n. sp. represents the 45th species assigned to the genus and the ninth from the Notropical Realm. It is distinguished from all other Neotropical species by the presence of a pair of sessile lateral papillae on its tail.     

Molecular identification and analysis of Borrelia burgdorferi sensu lato in lizards in the southeastern United States

Lyme borreliosis (LB) group spirochetes, collectively known as Borrelia burgdorferi sensu lato, are distributed worldwide. Wild rodents are acknowledged as the most important reservoir hosts. Ixodes scapularis is the primary vector of B. burgdorferi sensu lato in the eastern United States, and in the southeastern United States, the larvae and nymphs mostly parasitize certain species of lizards. The primary aim of the present study was to determine whether wild lizards in the southeastern United States are naturally infected with Lyme borreliae. Blood samples obtained from lizards in Florida and South Carolina were tested for the presence of LB spirochetes primarily by using B. burgdorferi sensu lato-specific PCR assays that amplify portions of the flagellin (flaB), outer surface protein A (ospA), and 66-kDa protein (p66) genes. Attempts to isolate spirochetes from a small number of PCR-positive lizards failed. However, PCR amplification and sequence analysis of partial flaB, ospA, and p66 gene fragments confirmed numerous strains of B. burgdorferi sensu lato, including Borrelia andersonii, Borrelia bissettii, and B. burgdorferi sensu stricto, in blood from lizards from both states. B. burgdorferi sensu lato DNA was identified in 86 of 160 (54%) lizards representing nine species and six genera. The high infection prevalence and broad distribution of infection among different lizard species at different sites and at different times of the year suggest that LB spirochetes are established in lizards in the southeastern United States.     

A new species of Rhabdias (Nematoda: Rhabdiasidae) in Calotes versicolor (Squamata: Agamidae) from Singapore

Rhabdias singaporensis n. sp. (Rhabditida: Rhabdiasidae) from the lungs of Calotes versicolor (Squamata: Agamidae) from Singapore is described and illustrated. Rhabdias singaporensis n. sp. represents the 77th species assigned to the genus, the eighth of the Asian region, and the second from Singapore. The distinguishing characteristic of the new species is the location of the excretory pore. In all species of Rhabdias for which excretory pore location data are available, the excretory pore is situated just posterior to the level of the nerve ring; in R. singaporensis , it lies near the esophageointestinal junction.     

A new species of Rhabdias from lungs of the wood frog, Rana sylvatica, in North America: the last sibling of Rhabdias ranae?

Rhabdias bakeri n. sp. is described from specimens found in lungs of the wood frog, Rana sylvatica, from North Dakota. The new species has previously been mistakenly identified as Rhabdias ranae Walton, 1929, a common parasite of the leopard frog, Rana pipiens. The new species differs from R. ranae and Rhabdias joaquinensis Ingles, 1935 by the shape and size of pseudolabia, shape and size of buccal capsule, and wider esophageal bulb. Molecular analysis based on the partial sequences of nuclear 18S rDNA gene, complete sequences of internal transcribed spacer region, and partial sequences of 28S gene demonstrates clear differences between Rhabdias from Ra. sylvatica and Ra. pipiens, and supports the status of R. bakeri as a new species.     

Molecular Identification and Analysis of Borrelia burgdorferi Sensu Lato in Lizards in the Southeastern United States

Lyme borreliosis (LB) group spirochetes, collectively known as Borrelia burgdorferi sensu lato, are distributed worldwide. Wild rodents are acknowledged as the most important reservoir hosts. Ixodes scapularis is the primary vector of B. burgdorferi sensu lato in the eastern United States, and in the southeastern United States, the larvae and nymphs mostly parasitize certain species of lizards. The primary aim of the present study was to determine whether wild lizards in the southeastern United States are naturally infected with Lyme borreliae. Blood samples obtained from lizards in Florida and South Carolina were tested for the presence of LB spirochetes primarily by using B. burgdorferi sensu lato-specific PCR assays that amplify portions of the flagellin (flaB), outer surface protein A (ospA), and 66-kDa protein (p66) genes. Attempts to isolate spirochetes from a small number of PCR-positive lizards failed. However, PCR amplification and sequence analysis of partial flaB, ospA, and p66 gene fragments confirmed numerous strains of B. burgdorferi sensu lato, including Borrelia andersonii, Borrelia bissettii, and B. burgdorferi sensu stricto, in blood from lizards from both states. B. burgdorferi sensu lato DNA was identified in 86 of 160 (54%) lizards representing nine species and six genera. The high infection prevalence and broad distribution of infection among different lizard species at different sites and at different times of the year suggest that LB spirochetes are established in lizards in the southeastern United States.     

Rhabdias rhampholeonis n. sp. and Rhabdias mariauxi n. sp. (Nematoda, Rhabdiasoidea), first lung worms from leaf chameleons: Description, molecular evidence and notes on biology

Rhabdias rhampholeonis n. sp. from Rhampholeon (Rh.) spectrum, Cameroon, and Rhabdias mariauxi n. sp. from Rieppeleon brevicaudatus, Tanzania, are the first lung worms from leaf chameleons. The new species are similar to the majority of species parasitic in chamaeleonids by having a long (≥10 mm) and thick body (≥500 µm), long oesophagus (≥800 µm), wide buccal capsule (≥40 µm) and low buccal ratio (<0.5). They most closely resemble Rhabdias chamaeleonis and Rhabdias cristati parasitic in Trioceros spp. from East Africa and Cameroon, respectively. Main distinctive characters are a buccal capsule composed of two segments and the head shape. The dorso-ventrally flattened buccal capsule of R. mariauxi n. sp. is unique in Rhabdias parasitising Chamaeleonidae. Sequences of the 12S rDNA and mitochondrial cytochrome c oxidase subunit 1 (coxI) genes were obtained and compared to those of Rhabdias okuensis, the only sequences published for chamaeleonid lung worms. The smallest nucleotide interspecific distances were found between R. mariauxi n. sp. and the former species of Trioceros from Cameroon. Hermaphroditism in females in the lungs, and R. mariauxi n. sp. free-living stages are like in other species from Chamaeleonidae, but the number of infective larvae produced per free-living female (one or two) was not fixed.     

Origin of the parasites of an invading species,the Australian cane toad (Bufo marinus): are the lungworms Australian or American?

Phylogeographical analyses that identify the geographical origin of parasites in invading species can clarify the parasites' potential for biological control of the invader and the risks posed by the parasite to native species. Our data on nuclear and mitochondrial genetic sequences show that the nematode lungworms (Rhabdias spp.) in invasive Australian populations of cane toads (Bufo marinus) are Rhabdias pseudosphaerocephala, a South American species. We did not find this lungworm species in any Australian frogs sympatric with cane toads, suggesting that the parasite does not attack Australian frogs and hence may offer potential as a biocontrol agent of the toad.     

Competition with wall lizards does not explain the alpine confinement of Iberian rock lizards: an experimental approach

Interspecific competition can limit the distribution of species along altitudinal gradients. It has been suggested that Western European rock lizards (genus Iberolacerta) are restricted to mountains due to the expansion of wall lizards (Podarcis), but there is no experimental evidence to corroborate this hypothesis. This study examines if interference competition with Podarcis muralis is a plausible explanation for the alpine confinement of Iberian rock lizards Iberolacerta cyreni. In a first experiment, we used an enclosure with four types of microhabitats to investigate whether adult rock and/or wall lizards shifted microhabitat or refuge preferences in the presence of the other species, and to detect aggressive interactions between them. In a second experiment, we staged heterospecific encounters between naïve, laboratory-born juveniles to identify behavioural differences and agonistic interactions. In the enclosure, neither rock nor wall lizards changed their microhabitat preferences in the presence of the other species. Nevertheless, rock lizards increased the diversity of microhabitats and nocturnal refuges used in the single species trials, which had twice the number of conspecifics. Aggressive interactions involved mainly large rock lizard males. Juveniles did not show any interspecific agonistic behaviour, but rock lizards spent more time basking and less time moving. Thus, we found no evidence of competition between both species in terms of habitat shifts or agonistic interactions, although intraspecific interactions seemed to explain the behaviour of adult rock lizards. We conclude that other factors are currently determining the alpine confinement of rock lizards.     

Phylogenetic affinities and systematic position of Entomelas sylvestris Baker, 1982 (Nematoda: Rhabdiasidae), a parasite of Breviceps sylvestris FitzSimons (Amphibia: Brevicipitidae) in South Africa

The genus Entomelas Travassos, 1930 currently includes nine species of rhabdiasid nematodes, eight of them parasitic in lizards and only one, Entomelas sylvestris Baker, 1982, parasitic in amphibians. Entomelas sylvestris was originally described from the Forest Rain Frog Breviceps sylvestris FitzSimons in South Africa and was not reported since. It was placed in the genus Entomelas without any specific arguments for this taxonomic decision, presumably mainly based on details of the buccal capsule morphology. We have found this species in the same host in Limpopo province, South Africa. Molecular phylogenetic analysis based on the newly-obtained sequence of complete ITS region and partial nuclear large ribosomal subunit (28S) gene of E. sylvestris and previously published sequences of a variety of other rhabdiasid taxa, has convincingly demonstrated that this species does not belong in Entomelas. Instead, it clustered together with the members of Rhabdias Stiles & Hassall, 1905 from amphibian hosts. Therefore, we transfer E. sylvestris into Rhabdias as Rhabdias sylvestris (Baker, 1982) n. comb. In our analysis E. sylvestris appears, albeit with weak support, as a basal/sister taxon to the rest of Rhabdias spp. which explains to some extent the differences in the buccal capsule morphology between this species and other Rhabdias spp.     

Rhabdias esculentarum n. sp. (Nematoda: Rhabdiasidae) from green frogs of the Rana esculenta species complex in Italy: molecular evidence, morphological description and genetic differentiation from its congeners in frogs and toads

A new taxon, Rhabdias esculentarum n. sp., is described based on DNA sequence analysis at multiple loci (i.e. mtDNA cox-1, 12S rRNA, ITS-1 and partial ITS-2 regions of the nuclear rDNA) and morphometric analysis carried out on specimens collected from the green frogs of the Rana esculenta species complex in Italy (i.e. R. lessonae Camerano and R. esculenta Linnaeus, identified genetically by diagnostic allozyme loci). Rhabdias esculentarum n. sp. was differentiated genetically, at both mitochondrial and nuclear levels, from Rh. bufonis (Schrank, 1788) (sensu Hartwich, 1972) and Rh. sphaerocephala Goodey, 1924 recovered from the toad Bufo bufo Linnaeus collected sympatrically with the specimens of Rana lessonae and R. esculenta examined in the present study. Moreover, the new taxon proved to be different from the other species of Rhabdias from anurans, which had previously been sequenced using the same genes and deposited in GeneBank. Phylogenetic analyses (MP and ML) inferred from mitochondrial (mtDNA cox-1 and 12S ribosomal RNA) and nuclear (ITS-1 and ITS-2 of the rDNA regions) sequences datasets were congruent in depicting Rh. esculentarum n. sp. as forming a highly supported clade distinct from the sympatric species Rh. bufonis, as well as from Rh. sphaerocephala, characterised on the basis of the same loci. Morphometric analysis and the differential diagnosis of genetically characterised specimens of the new species have revealed differences in several features in comparison with the type-species, Rh. bufonis. Material of the latter species included voucher specimens from Germany deposited by Hartwich (1972) and other specimens collected from B. bufo in Italy. Among the diagnostic characters, the particular cup-shaped buccal capsule characterising Rh. esculentarum is clearly different from the tear-shaped buccal capsule observed in material of R. bufonis obtained from Berlin Museum and collected in the same geographical area as the green frogs under study. Rh. esculentarum was also found to differ in some measurements and allometric characters from Rh. bufonis (sensu Moravec et al., 1997). The data so far collected appear to indicate a host-preference of Rh. esculentarum for Rana lessonae and R. esculenta, which belong to the R. esculenta hybridogenetic species complex in Italy.     

Three new species of Rhabdias Stiles et Hassall, 1905 (Nematoda: Rhabdiasidae) parasitic in Ptychadena spp. (Amphibia: Anura: Ptychadenidae) and an identification key to Rhabdias spp. from Afrotropical anurans

Three new species of lung-dwelling nematodes are described from the frogs Ptychadena anchietae (Bocage), P. oxyrhynchus (Smith), and P. uzungwensis (Loveridge) in southern Africa. All three species are medium-sized species of Rhabdias Stiles et Hassall, 1905, with the thick-walled buccal capsules measuring 11–13 μm × 6–11 μm, consisting of longer anterior and shorter posterior parts. Rhabdias athos n. sp. and R. porthos n. sp. are characterised by the rounded anterior end of the body and the presence of short dilatation of the oesophagus at its mid-length. Rhabdias porthos n. sp. has distinct excretory glands which are absent in two other species. Rhabdias aramis n. sp. is characterised by the truncated anterior end and the slight constriction of the oesophagus at the level of its mid-length. Phylogenetic analysis based on ITS-28S rDNA sequences placed R. aramis n. sp. in the clade consisting of R. engelbrechti Kuzmin et al., 2017 from South Africa and Eurasian Rhabdias spp., while R. athos n. sp. and R. porthos n. sp. formed a sister group to that clade. Identification key to 14 Rhabdias spp. parasitic in anuran amphibians from the Afrotropical Realm is provided.