Not that many leech species after all: Myzobdella lugubris and Myzobdella patzcuarensis (Annelida: Hirudinida) are the same species.

The genus Myzobdella groups five species of leeches parasites of fishes mainly of freshwater but with tolerance to brackish waters. Native distribution of these species includes the New World from North to South America. Myzobdella lugubris Leidy, 1851, the type species of the genus, was briefly described based on specimens from the USA, but subsequently their morphology, known distribution and host range were expanded; however, less is known about the other four species of the genus. As part of a survey focusing on characterizing the diversity of leeches from Mexico, specimens of Myzobdella patzcuarensis (Caballero, 1940), from the type locality of the species were included for the first time in a phylogenetic study. In addition, specimens assigned to Myzobdella from the southeast of Mexico as well as from Nicaragua, were also included. In the resulting phylogenetic tree, our newly generated sequences were found nested in the same clade that M. lugubris; with unresolved relationships and relatively low genetic divergence, suggesting conspecificity. In addition, the internal morphology of the specimens of Myzobdella from Mexico is consistent with the description of M. lugubris. Our morphological examination reveals high degrees of variability in the external pigmentation of the specimens. Based on our results we formally synonymize M. patzcuarensis under M. lugubris.

Biocontrol of snail-borne parasites with the glossiphoniid leech, Helobdella austinensis.

Parasites in which freshwater snails are intermediate hosts pose a serious threat to human health worldwide. We show here that freshwater snails can potentially be controlled by leech predation; in principle, this approach could significantly reduce snail-borne parasitic diseases (SBPDs). Specifically, glossiphoniid leeches, Helobdella austinensis and congener species, consume freshwater snails indiscriminately, while other common leeches do not. A single adult H. austenensis, for example, can consume up to its weight in snails, e.g. Physella acuta, per day. Our predator-prey models suggest that snail populations could be eliminated in relatively short time periods (approximately six months) using a leech biocontrol approach. This could have considerable impact on global SBPDs by breaking the intermediate host life cycle.

A new subspecies of Trypanosoma cyclops found in the Australian terrestrial leech Chtonobdella bilineata.

Previously, it was suggested that haemadipsid leeches represent an important vector of trypanosomes amongst native animals in Australia. Consequently, Chtonobdella bilineata leeches were investigated for the presence of trypanosome species by polymerase chain reaction (PCR), DNA sequencing and in vitro isolation. Phylogenetic analysis ensued to further define the populations present. PCR targeting the 28S rDNA demonstrated that over 95% of C. bilineata contained trypanosomes; diversity profiling by deep amplicon sequencing of 18S rDNA indicated the presence of four different clusters related to the Trypanosoma (Megatrypanum) theileri. Novy­MacNeal­Nicolle slopes with liquid overlay were used to isolate trypanosomes into culture that proved similar in morphology to Trypanosoma cyclops in that they contained a large numbers of acidocalcisomes. Phylogeny of 18S rDNA/GAPDH/ND5 DNA sequences from primary cultures and subclones showed the trypanosomes were monophyletic, with T. cyclops as a sister group. Blood-meal analysis of leeches showed that leeches primarily contained blood from swamp wallaby (Wallabia bicolour), human (Homo sapiens) or horse (Equus sp.). The leech C. bilineata is a host for at least five lineages of Trypanosoma sp. and these are monophyletic with T. cyclops; we propose Trypanosoma cyclops australiensis as a subspecies of T. cyclops based on genetic similarity and biogeography considerations.

Leeches as the intermediate host for strigeid trematodes: genetic diversity and taxonomy of the genera Australapatemon Sudarikov, 1959 and Cotylurus Szidat, 1928.

BACKGROUND: Leeches (Hirudinida) play a significant role as intermediate hosts in the circulation of trematodes in the aquatic environment. However, species richness and the molecular diversity and phylogeny of larval stages of strigeid trematodes (tetracotyle) occurring in this group of aquatic invertebrates remain poorly understood. Here, we report our use of recently obtained sequences of several molecular markers to analyse some aspects of the ecology, taxonomy and phylogeny of the genera Australapatemon and Cotylurus, which utilise leeches as intermediate hosts. METHODS: From April 2017 to September 2018, 153 leeches were collected from several sampling stations in small rivers with slow-flowing waters and related drainage canals located in three regions of Poland. The distinctive forms of tetracotyle metacercariae collected from leeches supplemented with adult Strigeidae specimens sampled from a wide range of water birds were analysed using the 28S rDNA partial gene, the second internal transcribed spacer region (ITS2) region and the cytochrome c oxidase (COI) fragment. RESULTS: Among investigated leeches, metacercariae of the tetracotyle type were detected in the parenchyma and musculature of 62 specimens (prevalence 40.5%) with a mean intensity reaching 19.9 individuals. The taxonomic generic affiliation of metacercariae derived from the leeches revealed the occurrence of two strigeid genera: Australapatemon Sudarikov, 1959 and Cotylurus Szidat, 1928. Phylogenetic reconstructions based on the partial 28S rRNA gene, ITS2 region and partial COI gene confirmed the separation of the Australapatemon and Cotylurus clades. Taking currently available molecular data and our results into consideration, recently sequenced tetracotyle of Australapatemon represents most probably Au. minor; however, unclear phylogenetic relationships between Au. burti and Au. minor reduce the reliability of this conclusion. On the other hand, on the basis of the obtained sequences, supplemented with previously published data, the metacercariae of Cotylurus detected in leeches were identified as two species: C. strigeoides Dubois, 1958 and C. syrius Dubois, 1934. This is the first record of C. syrius from the intermediate host. CONCLUSIONS: The results of this study suggest the separation of ecological niches and life cycles between C. cornutus (Rudolphi, 1808) and C. strigeoides/C. syrius, with potential serious evolutionary consequences for a wide range of host-parasite relationships. Moreover, phylogenetic analyses corroborated the polyphyletic character of C. syrius, the unclear status of C. cornutus and the separate position of Cotylurus raabei Bezubik, 1958 within Cotylurus. The data demonstrate the inconsistent taxonomic status of the sequenced tetracotyle of Australapatemon, resulting, in our opinion, from the limited availability of fully reliable, comparative sequences of related taxa in GenBank.

How parasite exposure and time interact to determine Australapatemon burti (Trematoda: Digenea) infections in second intermediate hosts (Erpobdella microstoma) (Hirudinea: Erpodellidae).

Australapatemon spp. are cosmopolitan trematodes that infect freshwater snails, aquatic leeches, and birds. Despite their broad geographic distribution, relatively little is known about interactions between Australapatemon spp. and their leech hosts, particularly under experimental conditions and in natural settings. We used experimental exposures to determine how Australapatemon burti cercariae dosage (number administered to leech hosts, Erpobdella microstoma) affected infection success (fraction to encyst as metacercariae), infection abundance, host survival, and host size over the 100 days following exposure. Interestingly, infection success was strongly density-dependent, such that there were no differences in metacercariae load even among hosts exposed to a 30-fold difference in cercariae. This relationship suggests that local processes (e.g., resource availability, interference competition, or host defenses) may play a strong role in parasite transmission. Our results also indicated that metacercariae did not become evident until ~4 weeks post exposure, with average load climbing until approximately 13 weeks. There was no evidence of metacercariae death or clearance over the census period. Parasite exposure had no detectable effects on leech size or survival, even with nearly 1,000 cercariae. Complementary surveys of leeches in California revealed that 11 of 14 ponds supported infection by A. burti (based on morphology and molecular sequencing), with an average prevalence of 32% and similar metacercariae intensity as in our experimental exposures. The extended development time and extreme density dependence of A. burti has implications for studying naturally occurring host populations, for which detected infections may represent only a fraction of cercariae to which animals have been exposed. Future investigation of these underlying mechanisms would be benefical in understanding host-parasite relationships.

The genetic diversity of blood parasites within the freshwater turtles Mauremys leprosa and Emys orbicularis in Tunisia reveals coinfection with Haemogregarina spp.

Haemogregarina species are apicomplexan blood parasites infecting vertebrates such as fish, lizards, and turtles. Due to the high morphological similarity of the erythrocytic stages infecting host species, it has always been a challenge to identify the true diversity of these parasites. Therefore, taxonomic studies are presently based on the combination of morphological and molecular data. In Tunisia, two species of Haemogregarina have been reported within the freshwater turtle Mauremys leprosa (Geoemydidae) for more than 40 years. Since M. leprosa occurs in the same aquatic environments as Emys orbicularis (Emydidae) in Tunisia, our objectives were to assess parasite diversity and specificity on the basis of both morphological and molecular approaches. The turtles were surveyed and sampled across six aquatic areas of Tunisia. Among the 39 specimens of M. leprosa and seven of E. orbicularis that were trapped and investigated, the presence of haemogregarines was detected in the blood of turtles only at sites where leeches were observed. Three 18S variants were identified, which corresponded to three distinct Haemogregarina species, among which one was identified as Haemogregarina stepanowi. The two other species that were detected are likely new to science. Because we show the occurrence of more than one blood parasite species within a single host specimen, our study provides the first report of coinfection with molecularly distinct Haemogregarina spp.

Morphological and molecular characterization of an African freshwater fish trypanosome, including its development in a leech vector.

Trypanosomes are ubiquitous blood parasites of fishes and at least 16 species were originally described infecting African freshwater fishes. This number was later reduced to six and in the late 1990s it was proposed that most records of freshwater fish trypanosomes across Africa are Trypanosoma mukasai Hoare, 1932. Recently, results from a molecular analysis of fish trypanosomes from the Okavango Delta, Botswana, reported the presence of at least two genotypic groups and concluded that the identification of T. mukasai remains problematic. The aims of the present study were thus to elucidate the life cycle of a freshwater fish trypanosome from southern Africa and to do a morphological and molecular characterization of this parasite from both the fish host and leech vector. To locate trypanosome stages, leeches were removed from fishes captured in the Phongolo River, South Africa, and fish blood films and leech squashes were Giemsa-stained and screened. To determine whether trypanosome stages in fishes and leeches were of the same genotype, DNA was extracted and fragments of the 18S rDNA gene were amplified and sequenced. Trypanosomes were detected in the fish families Cichlidae, Clariidae, Mochokidae and Schilbeidae. Sequence data showed that the trypanosome from one of the leeches, identified as Batracobdelloides tricarinata (Blanchard, 1897), was highly similar to those obtained from the plain squeaker, Synodontis zambezensis, with 0.7% difference recorded between them. From morphological and molecular data presented here, it is clear that the trypanosomes from Phongolo are closely related to those of the Okavango and should be considered as a single diverse species with genetic differentiation between 0.4-2.9%, under the 3-5% differences expected to be seen between true distinct species within the rRNA. Developmental stages of the trypanosome found in the leech B. tricarinata supports its status as the vector and the molecular evidence shows the relationship between the trypanosome in the fish and leech, but also illustrates the exceptional genetic and morphological diversity of a single species of trypanosome between host species. The work presented here provides us with clear information to take further steps in resolving the taxonomy and systematics of African freshwater fish trypanosomes.

First record of infestation by nasal leeches, Limnatis nilotica (Hirudinida, Praobdellidae), from cattle in Italy.

In July 2017, twenty cattle of a free-grazing herd were found to be infested with leeches in the mouth. Main signs were bloody sialorrhea and/or a purple-red colour of the lower lip. Leeches, in a variable number (1 to 3) per animal, were found at the lingual frenulum or on the sublingual vestibular mucosa and were morphologically identified as Limnatis nilotica. To the best of our knowledge, this is the first report of cattle infestation by L. nilotica in Italy. Besides recalling the attention to leech infestation and suggesting its inclusion in the differential diagnosis of animals with suggestive signs, this short report also provides practitioners with easy-going morphological keys for proper diagnosis and discrimination among species.

Infection, specificity and host manipulation of Australapatemon sp. (Trematoda, Strigeidae) in two sympatric species of leeches (Hirudinea).

Factors that drive parasite specificity and differences in infection dynamics among alternative host species are important for ecology and evolution of host-parasite interactions, but still often poorly known in natural systems. Here, we investigated spatiotemporal dynamics of infection, host susceptibility and parasite-induced changes in host phenotype in a rarely explored host-parasite system, the Australapatemon sp. trematode infecting two sympatric species of freshwater leeches, Erpobdella octoculata and Helobdella stagnalis. We show significant variation in infection abundance between the host species in both space and time. Using experimental infections, we also show that most of this variation likely comes from interspecific differences in exposure rather than susceptibility. Moreover, we demonstrate that the hiding behaviour of E. octoculata, but not that of H. stagnalis, was impaired by the infection irrespective of the parasite abundance. This may increase susceptibility of E. octoculata to predation by the final avian host. We conclude that differences in patterns of infection and in behavioural alterations among alternative sympatric host species may arise in narrow spatial scales, which emphasises the importance of local infection and transmission dynamics for parasite life cycles.

Larval stages of Neoplagioporus elongatus (Goto and Ozaki, 1930) (Opecoelidae: Plagioporinae), with notes on potential second intermediate hosts.

The morphology of sporocysts and cercariae of Neoplagioporus elongatus (Goto and Ozaki, 1930) is described for the first time. A cotylomicrocercous cercaria obtained from the sorbeoconch snail Semisulcospira nakasekoae was confirmed to be the cercaria of N. elongatus, based on the degree of sequence identity of the COI gene to that of adult worms. Freshwater annelids (oligochaetes and leeches) and some aquatic insects (odonates) were demonstrated experimentally to be potential second intermediate hosts.

Infections of Hypostomus spp. by Trypanosoma spp. and leeches: a study of hematology and record of these hirudineans as potential vectors of these hemoflagellates.

Among Kinetoplastida, the Trypanosoma is the genus with the highest occurrence infecting populations of marine fish and freshwater in the world, with high levels of prevalence, causing influences fish health and consequent economic losses, mainly for fish populations in situation stress. This study investigated infections of Hypostomus spp. by Trypanosoma spp. and leeches, as well as blood parameters of this host in the network of tributaries of the Tapajós River in the state of Pará, in the eastern Amazon region in Brazil. Of the 47 hosts examined, 89.4% were parasitized by Trypanosoma spp. and 55.4% also had leeches attached around the mouth. The intensity of Trypanosoma spp. increased with the size of the host, but the body conditions were not influenced by the parasitism. The number of red blood cells, and hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH), total number of leukocytes and thrombocytes showed variations and negative correlation with the intensity of Trypanosoma spp. in the blood of the hosts. The results suggest that the leeches were vectors of Trypanosoma spp. in Hypostomus spp.

Infections of Hypostomus spp. by Trypanosoma spp. and leeches: a study of hematology and record of these hirudineans as potential vectors of these hemoflagellates / Infecções de Hypostomus spp. por Trypanosoma spp. e Sanguessugas: um estudo hematológico e registro desses hirudíneos como potenciais vetores desses hemoflagelados

Abstract Among Kinetoplastida, the Trypanosoma is the genus with the highest occurrence infecting populations of marine fish and freshwater in the world, with high levels of prevalence, causing influences fish health and consequent economic losses, mainly for fish populations in situation stress. This study investigated infections of Hypostomus spp. by Trypanosoma spp. and leeches, as well as blood parameters of this host in the network of tributaries of the Tapajós River in the state of Pará, in the eastern Amazon region in Brazil. Of the 47 hosts examined, 89.4% were parasitized by Trypanosoma spp. and 55.4% also had leeches attached around the mouth. The intensity of Trypanosoma spp. increased with the size of the host, but the body conditions were not influenced by the parasitism. The number of red blood cells, and hemoglobin, mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), mean corpuscular hemoglobin (MCH), total number of leukocytes and thrombocytes showed variations and negative correlation with the intensity of Trypanosoma spp. in the blood of the hosts. The results suggest that the leeches were vectors of Trypanosoma spp. in Hypostomus spp.

Resumo Dentre os Kinetoplastida, Trypanosoma é o gênero com maior ocorrência, infectando populações de peixes marinhos e de água doce em todo o mundo. Apresenta elevados níveis de prevalência, ocasiona impactos na saúde dos peixes e consequente perdas econômicas, principalmente para populações de peixes em situação de estresse. Este estudo investigou a infecção por Trypanosoma spp. e sanguessugas em Hypostomus spp. e parâmetros sanguíneos desse hospedeiro do sistema de tributários do Rio Tapajós, no Estado do Pará, Amazônia Oriental, Brasil. De 47 hospedeiros examinados, 89,4% estavam parasitados por Trypanosoma spp., e 55,4% tinham também sanguessugas na região da boca. A intensidade de Trypanosoma spp. aumentou com o tamanho dos hospedeiros, mas as condições corporais não foram influenciadas pelo parasitismo. O número de eritrócitos, hematócrito, hemoglobina, VCM, HCM, CHCM, número de leucócitos e trombócitos totais apresentaram variações e correlação negativa com a intensidade de Trypanosoma spp. no sangue dos hospedeiros. Os resultados sugerem que sanguessugas foram os vetores de Trypanosoma spp. in Hypostomus spp.

Species of Apatemon Szidat, 1928 and Australapatemon Sudarikov, 1959 (Trematoda: Strigeidae) from New Zealand: linking and characterising life cycle stages with morphology and molecules.

Species of Apatemon Szidat, 1928 and Australapatemon Sudarikov, 1959 are reported from New Zealand for the first time, and their life cycles are resolved using molecular sequence data (28S and ITS rDNA regions and mitochondrial COI). The metacercaria of Apatemon sp. 'jamiesoni' ex Gobiomorphus cotidianus and its cercaria ex Potamopyrgus antipodarum are described in detail. Its adult, found in Anas platyrhynchos and Phalacrocorax punctatus, is identified by molecular sequence data. Apatemon sp. 'jamiesoni' uses a different species of snail host, exhibits consistent differences in the genetic markers examined and its single described adult differs from known species so as to be considered distinct, but its formal description awaits additional adult specimens. Australapatemon niewiadomski n. sp. is described from Anas platyrhynchos. It is distinguished morphologically by the absence of a ringnapf and its overall smaller size compared to most other Australapatemon spp. except Au. magnacetabulum and Au. minor, which are smaller in nearly all features than the new species. Au. niewiadomski n. sp. metacercaria and its intermediate host (Barbronia weberi) are identified via matching of molecular sequence data. The status of Apatemon and Australapatemon as distinct genera is confirmed based on their respective monophyly, and genetic divergence between them is comparable to other well-established genera in the Strigeidae. The diagnosis of Australapatemon is emended. Life history data, accurate patterns of host specialisation and distribution, alongside concurrent molecular and morphological evidence would be useful for an integrative taxonomical approach towards the elucidation of species diversity in this group.

Phylogenetic and morphological characterization of trypanosomes from Brazilian armoured catfishes and leeches reveal high species diversity, mixed infections and a new fish trypanosome species.

BACKGROUND: Several Trypanosoma species transmitted by leeches infect marine and freshwater fish worldwide. To date, all South American fish trypanosome species identified have been based on unreliable morphological parameters. We recently isolated and cultured trypanosomes from the Brazilian armoured catfishes Hypostomus luetkeni and H. affinis. Here, we report the first phylogenetic analyses of South American (Brazilian) trypanosomes isolated from fish, and from leeches removed from these fish. We also analysed morphologically and morphometrically the different forms of fish, leech and cultured trypanosomes. METHODS: V7V8 SSU rRNA and gGAPDH sequences were used for phylogenetic analysis of Brazilian fish and leech trypanosomes. Trypanosomes from cultures, fish blood and leech samples were also characterized morphologically and morphometrically by light and electron microscopy. RESULTS: In blood smears from fish high trypanosome prevalence (90-100 %) and parasitemia (0.9-1.0x10(2)) were observed. Phylogenetic relationships using SSU rRNA and gGAPDH showed that, despite relevant sequence divergence, all Brazilian fish (and derived cultures) and leech trypanosomes clustered together into a single clade. The Brazilian clade clustered with European, North American and African fish trypanosomes. Based on sequence analysis, we uncovered a new species of Brazilian fish trypanosome, Trypanosoma abeli n. sp. Trypanosoma abeli cultures contained pleomorphic epimastigotes, small trypomastigotes and rare sphaeromastigotes. Ultrastructural features of T. abeli included a cytostome-cytopharynx complex in epi- and trypomastigotes, a compact rod-like kinetoplast, lysosome-related organelles (LROs) and multivesicular bodies. Trypanosomes found in fish blood smears and leech samples were highly pleomorphic, in agreement with sequence data suggesting that catfishes and leeches often have mixed trypanosome infections. CONCLUSIONS: Trypanosoma abeli n. sp. is the first trypanosome from South American fishes isolated in culture, positioned in phylogenetic trees and characterized at the ultrastructural level. Trypanosoma abeli n. sp. is highly prevalent in H. luetkeni and H. affinis armoured catfish from the Atlantic Forest biome, and in other catfish species from the Amazon and the Pantanal. Sequencing data suggested that Brazilian catfish often have mixed trypanosome infections, highlighting the importance of molecular characterization to identify trypanosome species in fishes and leeches.

Novel genotypes of Trypanosoma binneyi from wild platypuses (Ornithorhynchus anatinus) and identification of a leech as a potential vector.

Little is known about the prevalence and pathogenesis of trypanosomes in Australian monotremes, and few genetic characterisation studies have been conducted with these haemoparasites. During the present investigation, molecular and microscopic methods were used to screen peripheral blood (n=28) and ectoparasites (n=10 adult ticks; n=5 tick nymphs; n=1 leech; and n>500 tick eggs) collected from wild Tasmanian platypuses (Ornithorhynchus anatinus), for the presence of trypanosomatid-specific DNA and/or trypomastigotes. The genes for the small ribosomal subunit RNA (18S rDNA) and glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH) were amplified and sequenced, prior to conducting phylogenetic analyses. The detection rate of the parasite-specific 18S rDNA in platypus blood was 85.7% (n=24/28), and the leech was also positive at both loci. Microscopically, high parasitaemia and the presence of abundant trypomastigotes, morphologically consistent with Trypanosoma binneyi Mackerras (1959), were observed in the blood films. Phylogenetic analyses at the 18S locus revealed the existence of four trypanosomatid-like genotypes, with variable similarity to two previously-described genotypes of T. binneyi (range of genetic p-distance: 0.0-0.5%). For the gGAPDH locus, for which only one T. binneyi sequence is available in GenBank, three genotypes closely related T. binneyi were identified (range of genetic p-distance: 0.1-0.4%). The leech-derived trypanosome isolate was virtually identical (at the two loci studied) to the other parasites sequenced from infected platypuses; however, the molecular or morphological identification of the leech species was not possible. Although further studies are required, the molecular detection of trypanosomes in an aquatic leech removed from a platypus, suggests the possibility that these haematophagous hirudineans may be a vector for T. binneyi (and closely related genotypes).

Morphological and molecular characterization of a marine fish trypanosome from South Africa, including its development in a leech vector.

BACKGROUND: Trypanosomes are ubiquitous blood parasites of marine and freshwater fishes, typically transmitted by aquatic leeches. Phylogenetic studies have been dominated by examples derived from freshwater fishes, with few marine representatives. Furthermore, life cycle studies on marine fish trypanosomes have focused on those of the northern hemisphere. In this investigation, we have examined the life cycle and molecular taxonomy of a marine fish trypanosome from South Africa. METHODS: To locate trypanosome stages, leeches were removed from fishes captured on the west and south coasts of South Africa, and fish blood films and leech squashes were Giemsa-stained and screened; leeches were also examined histologically. To determine whether trypanosome stages in fishes and leeches were of the same genotype, DNA was extracted from Giemsa-stained fish blood films and leech squashes, and from fish whole blood. Fragments of the 18S rRNA gene were amplified by PCR using trypanosome-specific primers and sequenced. Resulting sequence data were compared with each other and with published trypanosome 18S rDNA sequences, and used for phylogenetic analysis. RESULTS: Trypanosomes were detected in blood films from fishes of the families Clinidae, Blenniidae and Gobiidae. The flagellates ranged in size and staining properties within the films and across fish hosts. In squashes and histological sections of adult and juvenile leeches, identified as Zeylanicobdella arugamensis, trypanosome developmental stages were predominantly slender epimastigotes. Sequence data showed that trypanosomes derived from fishes were identical, irrespective of whether they were small or large forms; sequences derived largely from leech epimastigotes were also identical to those obtained from fish trypanosomes. Fish and leech trypanosome sequences fell into a marine fish aquatic clade, and aligned most closely with two trypanosome sequences from marine fishes off Norway. CONCLUSIONS: Combined morphological and molecular methods indicate that the trypanosomes examined here represent a single pleomorphic species, rather than the three species described originally. This species is identified as Trypanosoma nudigobii Fantham, 1919 with the leech Z. arugamensis as its vector, and T. capigobii Fantham, 1919 and T. blenniclini Fantham, 1930 are regarded as junior synonyms of the species. Phylogenetic analysis establishes its affinity with marine fish trypanosomes off Norway.

Haemogregarines from western Palaearctic freshwater turtles (genera Emys, Mauremys) are conspecific with Haemogregarina stepanowi Danilewsky, 1885.

The majority of Haemogregarina species have been based on the morphology of their erythrocytic stages and supposed strict host specificity. The quantity of species with a limited number of overlapping diagnostic traits has led to a considerable mess in haemogregarine taxonomy and significant synonymy. We analysed host specificity, intra- and interspecific variability, evolutionary relationships, and the distribution of the type species of the genus Haemogregarina--H. stepanowi. The morphology of blood stages and 18S rDNA sequences of this haemogregarine from four western Palaearctic hard-shelled freshwater turtles (Emys orbicularis, Mauremys caspica, Mauremys leprosa and Mauremys rivulata) were compared with Haemogregarina balli. Additional sequences of 18S rDNA of Haemogregarina-like isolates collected from three species of African hinged terrapins (genus Pelusios) were used to enlarge the dataset for phylogenetic analyses. Thirteen sequences (1085 bp) of Haemogregarina representing all four western Palaearctic turtle species were identical, corresponding to H. stepanowi, which is closely related to the Nearctic species H. balli. In our analyses, Haemogregarina spp. constituted a monophyletic clade sister to the genus Hepatozoon. Haemogregarina stepanowi possesses a wide distribution range from the Maghreb, through Europe, Turkey and the Middle East to Iran. We consider that the genus Haemogregarina has a low host specificity crossing the family level of its vertebrate hosts and that its distribution is likely to be linked to the vector and definitive host--the leech.

Alloglossidium demshini sp. nov. (Digenea: Macroderoididae) from leeches in Minnesota.

Alloglossidium demshini sp. nov. is described based on specimens from leeches Haemopis grandis collected in northwestern Minnesota. The new species is morphologically closest to Alloglossidium schmidti. The two species can be readily differentiated based on several morphological characters. The cirrus sac in A. schmidti is almost entirely situated anterior to the ventral sucker while in A. demshini sp. nov. it is situated dorsal to the ventral sucker and its proximal end almost reaches the posterior end of ventral sucker or extends posterior to it. The new species has a prepharynx that is substantially longer than the esophagus while in A. schmidti the situation is the opposite. The two species also differ in the position of the ovary and the position of the testes and vitelline fields in relation to the ends of the ceca. Hirudineatrema oschmarini described from leeches in Eastern Palaearctic and Alloglossidium richardsoni described in North America demonstrate great morphological similarity. Nevertheless, Hirudineatrema cannot be synonymized with Alloglossidium at this point because of several peculiar morphological features of H. oschmarini such as a V-shaped excretory bladder and the apparent presence of a true seminal receptacle in the latter species. These features need to be re-evaluated before any taxonomic decision can be made.

The life cycle of Australapatemon magnacetabulum (Digenea: Strigeidae) from Northwestern Argentina.

The life cycle of Australapatemon magnacetabulum Dubois, 1988 was resolved experimentally. Planorbid snails Biomphalaria tenagophila (d'Orbigny, 1835) collected in a small pond at the confluence of the San Lorenzo and Arias Rivers, near Salta City, Province of Salta, Argentina, were found to be shedding furcocercous cercariae possessing 4 pairs of penetration glands, 1 pair of unpigmented eyespots, 6 pairs of flame cells in the body, and 1 pair in the tail stem. Metacercariae were found encysted in naturally, and experimentally, exposed leeches Helobdella adiastola Ringuelet, 1972, Helobdella triserialis (Blanchard, 1849), Haementeria eichhorniae Ringuelet 1978, and Haementeria sp., and within their sporocysts in naturally infected planorbid intermediate hosts. Sexually mature adults were recovered from domestic chicks and a duck 8-28 days postexposure by metacercariae from leeches. The identification of the species was based upon the characteristic large ventral sucker and a genital cone, crossed by a hermaphroditic duct with internal folds, occupying approximately a 1/4 to 1/5 of the hindbody.