New species of Polystomoides (Monogenoidea: Polystomatidae) parasitizing the urinary bladder of a freshwater turtle in Brazil.

Trachemys dorbigni is the most abundant freshwater turtle species in Rio Grande do Sul, southern Brazil. Chelonians are known to host a wide variety of pathogens, including viruses, bacteria, hemoparasites and helminths. Among these, nine genera of polystomatid flatworms (Monogenoidea; Polystomatidae) infect freshwater turtles: Apaloneotrema, Aussietrema, Fornixtrema, Manotrema, Pleurodirotrema, Polystomoidella, Polystomoides, Uropolystomoides and Uteropolystomoides. However, little is known about the biology of these parasites in the Neotropical Realm. Through investigative cystoscopy, specimens of Polystomatidae were located inside the urinary bladder of the host T. dorbigni. Retrieved specimens were fixed and stained whole mounts prepared for taxonomic identification. In the present paper, a new species of Polystomoides (Monogenoidea: Polystomatidae) parasitizing the urinary bladder of a freshwater turtle of the species T. dorbigni in Brazil is described. Polystomoides santamariensis n. sp. differs from the congeneric species on the length of the genital spines, which are longer. Given the enormous diversity of freshwater turtles around the world, it is likely that a large number of chelonian polystomatids are still unknown.

Morphology and molecular characterization of Polystoma goeldii n. sp. (Monogenea, Polystomatidae) parasite from the urinary bladder of Physalaemus ephippifer (Steindachner) (Anura, Leptodactylidae).

Polystomatid flatworms of amphibians are represented in the Neotropical realm by species of Mesopolystoma, Nanopolystoma, Parapseudopolystoma, Polystoma, Riojatrema and Wetapolystoma but only species of Polystoma are known from Brazil, namely Polystoma cuvieri, P. knoffi, P. lopezromani and P. travassosi. During a survey of monogeneans infecting amphibians in the north-eastern region of Pará State, the Cayenne Caecilian Typhlonectes compressicauda was found to be infected with Nanopolystoma tinsleyi and the Veined Tree Frog Trachycephalus typhonius was found to harbor Polystoma lopezromani. A yet unknown species of Polystoma was also encountered in the urinary bladder of the Steindachner's Dwarf Frog, Physalaemus ephippifer. This new species, which is the second species reported from Physalaemus spp., is described herein as Polystoma goeldii n. sp. and its life cycle is also illustrated. The new species can be distinguished from Polystoma spp. from other neotropical realm by a combination of characteristics, including hamuli morphology, outer/inner hamuli length ratio, haptor/total body length ratio, genital bulb/total body length ratio, genital spine number and COI molecular characters.

New species of Polystomoides (Monogenoidea: Polystomatidae) parasitizing the urinary bladder of a freshwater turtle in Brazil / Nova espécie de Polystomoides (Monogenoidea: Polystomatidae) parasitando a bexiga urinária de uma tartaruga de água doce no Brasil

Trachemys dorbigni is the most abundant freshwater turtle species in Rio Grande do Sul, southern Brazil. Chelonians are known to host a wide variety of pathogens, including viruses, bacteria, hemoparasites and helminths. Among these, nine genera of polystomatid flatworms (Monogenoidea; Polystomatidae) infect freshwater turtles: Apaloneotrema, Aussietrema, Fornixtrema, Manotrema, Pleurodirotrema, Polystomoidella, Polystomoides, Uropolystomoides and Uteropolystomoides. However, little is known about the biology of these parasites in the Neotropical Realm. Through investigative cystoscopy, specimens of Polystomatidae were located inside the urinary bladder of the host T. dorbigni. Retrieved specimens were fixed and stained whole mounts prepared for taxonomic identification. In the present paper, a new species of Polystomoides (Monogenoidea: Polystomatidae) parasitizing the urinary bladder of a freshwater turtle of the species T. dorbigni in Brazil is described. Polystomoides santamariensis n. sp. differs from the congeneric species on the length of the genital spines, which are longer. Given the enormous diversity of freshwater turtles around the world, it is likely that a large number of chelonian polystomatids are still unknown.(AU)

Trachemys dorbigni é a espécie de tartaruga de água doce mais abundante do Rio Grande do Sul, no Sul do Brasil. Sabe-se que os quelônios são hospedeiros de uma grande variedade de patógenos, incluindo vírus, bactérias, hemoparasitos e helmintos. Dentre estes, oito gêneros de Polystomatidae (Platyhelminthes: Monogenoidea) infectam tartarugas de água doce: Apaloneotrema, Aussietrema, Fornixtrema, Manotrema, Pleurodirotrema, Polystomoidella, Polystomoides, Uropolystomoides e Uteropolystomoides. No entanto, pouco ainda se sabe sobre a biologia destes parasitos na Região Neotropical. Durante uma citoscopia investigativa, foram observados espécimes de Polystomatidae localizados no interior da bexiga urinária de T. dorbigni. Os espécimes coletados foram fixados e corados para identificação taxonômica. No presente artigo, uma nova espécie de Polystomoides (Monogenoidea: Polystomatidae) parasitando a bexiga urinária de tartaruga de água doce da espécie T. dorbigni no Brasil é descrita. Polystomoides santamariensis n. sp. difere das demais espécies no tamanho dos espinhos genitais, que são maiores. Devido a enorme diversidade de tartarugas de água doce ao redor do mundo, é provável que um grande número de polistomatídeos de quelônios ainda seja desconhecido.(AU)

Eye to eye: classification of conjunctival sac polystomes (Monogenea: Polystomatidae) revisited with the description of three new genera Apaloneotrema n. g., Aussietrema n. g. and Fornixtrema n. g.

Polystomes (Monogenea: Polystomatidae) of freshwater turtles are currently represented by five genera, namely Neopolystoma, Polystomoides, Polystomoidella, Uropolystomoides and Uteropolystomoides. These parasites can infect the urinary, oral and/or the conjunctival sac systems of their hosts, showing strict site specificity. A recent phylogenetic study showed that the two most diverse genera within chelonian polystomes, i.e. Neopolystoma and Polystomoides, are not monophyletic. Furthermore, polystomes infecting the conjunctival sacs of their host, except for one species, formed a robust lineage. A fusiform egg shape has been reported for conjunctival sac polystomes and it was assumed that this characteristic could be a good character for the systematics of polystomes. Our objective in the present work was, therefore, to study more in depth the morphology of polystomes collected from the conjunctival sacs of chelonians to find characters defining a putative new genus. To achieve this objective, more specimens were collected in 2018 and 2019 from turtles sampled in North Carolina and Florida (USA) to extend taxon sampling for the phylogenetic analysis. Morphological characters of relevant polystome specimens were re-examined from several collections from Asia, Australia, Europe, South Africa, South America and North America. Based on a Bayesian tree inferred from the analysis of four concatenated genes, namely 12S, 18S, 28S and COI, polystomes found in the conjunctival sacs were grouped in three distinct lineages, the first one including a single species infecting an Australian pleurodire turtle; the second one including eleven species infecting cryptodire turtles of South America, North America and Asia; and the last one including a single species infecting a softshell cryptodire turtle of North America. Based on observations of live specimens by Dr. Sylvie Pichelin and our morphological analysis, the conjunctival sac polystomes from Australian turtles are small, cannot extend their body significantly, have a spherical ovary and egg, have a large genital bulb and possess latero-ventral vaginae at the level of the testis. Based on observations of live specimens and morphological analysis of whole mounted specimens, polystomes of the second lineage share the following morphological characteristics: the ability to stretch out and double their length, a long oval ovary, a separate egg-cell-maturation-chamber, fusiform to diamond-shaped eggs with acute tips, small genital bulb and vaginae peripheral on the side of the body at the level of the testis. The polystome species of the third lineage occupies a basal position, has the ability to stretch out and possess an elongated ovary, a large fusiform egg with rounded tips, a small genital bulb and small latero-ventral vaginae at the level of the ovary. These three distinct conjunctival sac polystome lineages are herein described as separate new genera, Aussietrema, Fornixtrema and Apaloneotrema, respectively.

Polystoma knoffi n. sp. and Polystoma travassosi n. sp. (Monogenea: Polystomatidae): naming museum-archived specimens from Brazil.

In 1978, Kohn and co-workers deposited several polystome (Monogenea) specimens infecting several Brazilian anurans [Trachycephalus mesophaeus (Hensel), T. nigromaculatus Tschudi and Leptodactylus pentadactylus (Laurenti)] within the Helminthological Collection of the Instituto Oswaldo Cruz, Brazil. No specimen was formally described but we herein identified three morphotypes and formally describe two of them (Polystoma knoffi n. sp. and P. tavassosi n. sp.). These are respectively the 12th and 13th species of Polystoma described from South America. For both species, the intestine forms a reticulated network, a characteristic unique to most Neotropical species of Polystoma.

Tracking platyhelminth parasite diversity from freshwater turtles in French Guiana: First report of Neopolystoma Price, 1939 (Monogenea: Polystomatidae) with the description of three new species.

BACKGROUND: Polystomatid flatworms in chelonians are divided into three genera, i.e. Polystomoides Ward, 1917, Polystomoidella Price, 1939 and Neopolystoma Price, 1939, according to the number of haptoral hooks. Among the about 55 polystome species that are known to date from the 327 modern living chelonians, only four species of Polystomoides are currently recognised within the 45 South American freshwater turtles. METHODS: During 2012, several sites in the vicinity of the cities Cayenne and Kaw in French Guiana were investigated for freshwater turtles. Turtles were collected at six sites and the presence of polystomatid flatworms was assessed from the presence of polystome eggs released by infected specimens. RESULTS: Among the three turtle species that were collected, no polystomes were found in the gibba turtle Mesoclemmys gibba (Schweigger, 1812). The spot-legged turtle Rhinoclemmys punctularia (Daudin, 1801) was infected with two species of Neopolystoma Price, 1939, one in the conjunctival sacs and the other in the urinary bladder, while the scorpion mud turtle Kinosternon scorpioides (Linnaeus, 1766) was found to be infected with a single Neopolystoma species in the conjunctival sacs. These parasites could be distinguished from known species of Neopolystoma by a combination of morphological characteristics including body size, number and length of genital spines, shape and size of the testis. They were also differentiated at the molecular level using the cox1 gene marker. Based on morphological and genetic evidences, three new species are described herein, namely Neopolystoma cayensis n. sp. and Neopolystoma guianensis n. sp. from the bladder and the conjunctival sacs of R. punctularia, respectively, and Neopolystoma scorpioides n. sp. from the conjunctival sacs of K. scorpioides. However the monophyly of Polystomoides and Neopolystoma is still questioned regarding their phylogeny based on a dataset comprising four concatenated genes, namely, 18S, 28S and 12S rRNA genes and cox1. CONCLUSIONS: In addition to these being the first chelonian polystomes to be reported and described from French Guiana, they represent the first polystomes from the hosts K. scorpioides and R. punctularia and the first representatives of Neopolystoma from South America. Chelonian polystomes now require an in-depth morphological study to reconcile the taxonomy of the genera with species evolution.

Ultrastructural Comparison of Hepatozoon ixoxo and Hepatozoon theileri (Adeleorina: Hepatozoidae), Parasitising South African Anurans.

To date, only two haemogregarine parasite species have been described from South African anurans: Hepatozoon ixoxo, infecting toads of the genus Sclerophrys (syn. Amietophrynus); and Hepatozoon theileri, parasitising the common river frog, Amietia quecketti. Both species have been characterised using limited morphology, and molecular data from PCR amplified fragments of the 18S rRNA gene. However, no ultrastructural work has been performed thus far. The aim of this study was to add descriptive information on the two species by studying their ultrastructural morphology. Mature gamont stages, common in the peripheral blood of infected frogs, were examined by transmission electron microscopy. Results indicate that H. ixoxo and H. theileri share typical apicomplexan characteristics, but differ markedly in their external cellular structure. Hepatozoon ixoxo is an encapsulated parasite presenting a prominent cap at the truncate pole, and shows no visible modifications to the host cell membrane. In comparison, H. theileri does not present a capsule or cap, and produces marked morphological changes to its host cell. Scanning electron microscopy was performed to further examine the cytopathological effects of H. theileri, and results revealed small, knob-like protrusions on the erythrocyte surface, as well as notable distortion of the overall shape of the host cell.

Some nematodes of the genus Rhabdias Stiles et Hassall, 1905 (Nematoda: Rhabdiasidae) parasitising amphibians in French Guiana.

Based on material collected from Rhinella cf. margaritifera (Laurenti) and Rhi. marina (Linnaeus) (Anura: Bufonidae) during a parasite survey of the herpetofauna of French Guiana, updated descriptions of Rhabdias androgyna Kloss, 1971 and R. fuelleborni Travassos, 1926 are presented. In addition to metrical data, which may overlap in closely related species, emphasis is placed on qualitative characters. Rhabdias androgyna is distinguished by the unique presence of an outer and inner cephalic cuticular inflation, a shoulder-like broadening of the body at the anterior end, a wide and shallow buccal capsule (average buccal ratio 0.36) with serrated lumen in apical view, a prominent anterior dilatation of the oesophagus, and the presence of an additional posterior dilatation anterior to the oesophageal bulb. Characters that may help to differentiate R. fuelleborni from closely related species parasitising the Rhi. marina species group are the presence of six relatively uniform lips, and the division of the buccal capsule into an anterior and posterior segment, with differently structured walls. Both the presence of R. androgyna and R. fuelleborni in French Guiana constitute new geographic records. A single specimen of Rhabdias sp. is described from Pristimantis chiastonotus (Lynch et Hoegmood) (Anura: Craugastoridae). This species differs from all its Neotropical congeners by the distinct globular swelling of its head, similar to that seen in only one Palaearctic and one Afrotropical Rhabdias species. A list of species of Rhabdias parasitising amphibians in the Netropical Realm is also provided.

Assessment of platyhelminth diversity within amphibians of French Guiana revealed a new species of Nanopolystoma (Monogenea: Polystomatidae) in the caecilian Typhlonectes compressicauda.

An expedition was undertaken to French Guiana in search of amphibian parasites. Of the 23 anuran species collected and screened for polystomes, the toad Rhinella margaritifera (Laurenti) was the sole species found to be infected with a polystome, namely Wetapolystoma almae Gray, 1983. Of the two caecilian species collected, a new species of Nanopolystoma du Preez, Huyse et Wilkinson, 2008 was discovered from the urinary bladder of the aquatic caecilian Typhlonectes compressicauda (Duméril et Bibron). The small size of the mature worm, two non-diverticulated caeca of equal length that are non-confluent posteriorly, vitelline follicles in two dense lateral fields, a single follicular testis in the middle of the body, small ovary and a single operculated egg in utero, vaginae present and the caecilian host allowed the identification of the specimen as Nanopolystoma. Larger body size, hamulus length, egg diameter and occurrence in the caecilian family Typhlonectidae distinguishes the new species from the two other known polystomes in Nanopolystoma; thus, the description of Nanopolystoma tinsleyi sp. n. is provided within this paper.

Origin of the amphibian chytrid fungus.

The sudden appearance of chytridiomycosis, the cause of amphibian deaths and population declines in several continents, suggests that its etiologic agent, the amphibian chytrid Batrachochytrium dendrobatidis, was introduced into the affected regions. However, the origin of this virulent pathogen is unknown. A survey was conducted of 697 archived specimens of 3 species of Xenopus collected from 1879 to 1999 in southern Africa in which the histologic features of the interdigital webbing were analyzed. The earliest case of chytridiomycosis found was in a Xenopus laevis frog in 1938, and overall prevalence was 2.7%. The prevalence showed no significant differences between species, regions, season, or time period. Chytridiomycosis was a stable endemic infection in southern Africa for 23 years before any positive specimen was found outside Africa. We propose that Africa is the origin of the amphibian chytrid and that the international trade in X. laevis that began in the mid-1930s was the means of dissemination.