Superfamily Microphalloidea Research Articles

Jumping continents and major host lineages: phylogeny and diversity of the enigmatic Cryptotropidae (Platyhelminthes: Digenea).

Members of several genera in the digenean superfamily Microphalloidea, namely Renschetrema, Rohdetrema, Cryptotropa, Cephalouterina and Pseudocryptotropa, are characterized by an unusual dorsal position of the genital atrium. In the absence of phylogenetic data, their systematic position has been unstable. In the most recent taxonomic revision of the Microphalloidea, they were housed in three different families. We studied the morphology and obtained DNA sequences of several microphallolideans with a dorsal genital pore, collected from vertebrates in Southeast Asia and South America. We used sequences of the nuclear 28S gene to infer a superfamily-level phylogeny and sequences of the mitochondrial cox1 gene for family-level phylogeny and species-level comparisons. Based on the combination of molecular phylogenetic data and morphological features, we restore the Cryptotropidae and synonymize the Renschetrematidae with the Cryptotropidae. We erect new genera Paracryptotropagen. nov. and Armadoatriumgen. nov., provide amended diagnoses of the Cryptotropidae and Renschetrema and provide keys to the identification of genera within the family. We resurrect the genus Novetrema, previously synonymized with Pseudocryptotropa, and remove Renschetrema indicum from Renschetrema. We describe four new species from lizards in Vietnam and birds in the Philippines and Peru. The unique morphological features and unusually broad host associations and geographical distributions of cryptotropids are discussed.

Phylogenetic relationships of the Renschetrematidae Yamaguti, 1971 with description of a new species of Renschetrema Rohde, 1964 from the Philippines.

Renschetrematidae is a very small family of digeneans parasitic in bats in southern and Southeast Asia. According to the original descriptions and the latest revision, its representatives are characterized by the presence of several unusual characters. Among them are the dorsal position of the genital pores, separate male and female genital pores, and the presence of an accessory sac (stylet pouch) associated with terminal genitalia and containing a stylet-like structure. Prior to our study, the phylogenetic relationships of the Renschetrematidae were unknown and DNA sequence data were absent from any of its representatives. In this work, we present the description of a new species of Renschetrema from bats in the Philippines. We also evaluate the phylogenetic affinities of the Renschetrematidae using newly obtained partial sequences of the 28S rRNA gene from Renschetrema specimens collected in the Philippines and Southeast China. The new species differs from previously described species by the position and orientations of the stylet pouch, presence of accessory spines around genital atrium, position of gonads, body shape and relative size of pharynx and oral sucker. Our phylogenetic analysis supports the status of the Renschetrematidae as an independent family within the superfamily Microphalloidea. In the phylogenetic tree, the Renschetrematidae appeared as an independent family-level lineage, basal to the remaining taxa within the Microphalloidea. Detailed examination of our specimens revealed significant errors in the current diagnoses of the genus Renschetrema and the Renschetrematidae. Amended diagnoses of the genus and the family are provided.

Mitochondrial genomes of two eucotylids as the first representatives from the superfamily Microphalloidea (Trematoda) and phylogenetic implications

BackgroundThe Eucotylidae Cohn, 1904 (Superfamily: Microphalloidea), is a family of digeneans parasitic in kidneys of birds as adults. The group is characterized by the high level of morphological similarities among genera and unclear systematic value of morphological characters traditionally used for their differentiation. In the present study, we sequenced the complete or nearly complete mitogenomes (mt genome) of two eucotylids representing the genera Tamerlania (T. zarudnyi) and Tanaisia (Tanaisia sp.). They represent the first sequenced mt genomes of any member of the superfamily Microphalloidea.MethodsA comparative mitogenomic analysis of the two newly sequenced eucotylids was conducted for the investigation of mitochondrial gene arrangement, contents and genetic distance. Phylogenetic position of the family Eucotylidae within the order Plagiorchiida was examined using nucleotide sequences of mitochondrial protein-coding genes (PCGs) plus RNAs using maximum likelihood (ML) and Bayesian inference (BI) methods. BI phylogeny based on concatenated amino acids sequences of PCGs was also conducted to determine possible effects of silent mutations.ResultsThe complete mt genome of T. zarudnyi was 16,188 bp and the nearly complete mt genome of Tanaisia sp. was 13,953 bp in length. A long string of additional amino acids (about 123 aa) at the 5′ end of the cox1 gene in both studied eucotylid mt genomes has resulted in the cox1 gene of eucotylids being longer than in all previously sequenced digeneans. The rrnL gene was also longer than previously reported in any digenean mitogenome sequenced so far. The TΨC and DHU loops of the tRNAs varied greatly between the two eucotylids while the anticodon loop was highly conserved. Phylogenetic analyses based on mtDNA nucleotide and amino acids sequences (as a separate set) positioned eucotylids as a sister group to all remaining members of the order Plagiorchiida. Both ML and BI phylogenies revealed the paraphyletic nature of the superfamily Gorgoderoidea and the suborder Xiphidiata.ConclusionsThe average sequence identity, combined nucleotide diversity and Kimura-2 parameter distances between the two eucotylid mitogenomes demonstrated that atp6, nad5, nad4L and nad6 genes are better markers than the traditionally used cox1 or nad1 for the species differentiation and population-level studies of eucotylids because of their higher variability. The position of the Dicrocoeliidae and Eucotylidae outside the clade uniting other xiphidiatan trematodes strengthened the argument for the need for re-evaluation of the taxonomic content of the Xiphidiata.Graphical

New type of xiphidiocercariae (Digenea: Microphalloidea) from South Vietnam.

We found unusual digenean intramolluscan stages, sporocysts and cercariae, in gastropods Sulcospira dautzenbergiana (Morelet) (Caenogastropoda: Pachychilidae) from Southern Vietnam and named them Cercaria cattieni 1. These cercariae have a stylet and thus belong to the Xiphidiata. However, such combination of characters as extremely large body size and I-shaped excretory bladder has not been found before in any other xiphidiocercariae. We obtained COI, ITS1, 5.8S + ITS2, and 28S rDNA sequences for C. cattieni 1. The latter allowed us to specify the phylogenetic position of the discovered cercariae: C. cattieni 1 falls within the superfamily Microphalloidea and is most closely grouped to Pachypsolus irroratus (Rudolphi, 1819) (Pachypsolidae), the sea turtle parasite. Information on the family Pachypsolidae is limited. Judging from the molecular phylogeny, C. cattieni 1 might be the larva of the Pachypsolidae, documented for the first time.

Helminth Fauna of Tadarida brasiliensis (Mammalia, Chiroptera) in the State of Rio Grande do Sul, Brasil: A Comparative Approach

Chiroptera is the second largest order of mammals in terms of species richness, yet little data are available on the helminth fauna infecting bats. The goal of this paper was therefore to describe the helminth fauna of a common bat species from the Brazilian state of Rio Grande do Sul. We collected 63 individuals of the bat Tadarida brasiliensis in the municipality of Montenegro in March 2015 (33 males and 30 females; 41 adults and 22 juveniles). We identified 451 endoparasites belonging to eight species (i.e. Urotrema scabridum, Limatulum oklahomense, Postorchigenes paraguayensis, Parabascus limatulus, Ochoterenatrema sp., Vampirolepis decipiens, Tadaridanema delicatus, as well as one unidentified species representing the superfamily Microphalloidea). Based on their importance value, we classified two helminth species as ‘dominant’, four as ‘co-dominant’ and two as ‘subordinate'. Vampirolepis decipiens had both the highest prevalence (of 55.5%) and greatest abundance (3.52 parasites/host). We report for the first time P. limatulus in T. brasiliensis in Rio Grande do Sul. This study provides important base-line data to elucidate helminth infestations in T. brasiliensis in Brazil.

Ultrastructure of the spermatozoon of Lecithostaphylus parexocoeti (Digenea, Microphalloidea, Zoogonidae) parasite of the flying fish Cheilopogon pinnatibarbatus (Teleostei, Exocoetidae) off Senegal and their implication on the phylogenetic relationships in Microphalloidea

This study shows the ultrastructure of the mature spermatozoon of Lecithostaphylus parexocoeti (Digenea, Microphalloidea, Zoogonidae) parasite of the flying fish Cheilopogon pinnatibarbatus (Exocoetidae) captured in the Atlantic Ocean near Dakar (Senegal). This is the first report of L. parexocoeti from Senegal and from this host species. The mature spermatozoon is filiform and exhibits two axonemes of the 9+“1” pattern of the Trepaxonemata, an external ornamentation associated with spine-like bodies, parallel cortical microtubules, a nucleus, two mitochondria and granules of glycogen. The particularities of the spermatozoon of L. parexocoeti are the location of the first mitochondrion and the morphology of its anterior extremity with only cortical microtubules and external ornamentations of the plasma membrane. To our knowledge, this type of anterior extremity has never been described in the superfamily Microphalloidea. However, the ultrastructure of the posterior extremity of the spermatozoon corresponds to the fasciolidean type that was previously described in the Zoogonidae.

Molecular phylogenetic location of a digenean larva isolated from the African ampullariid snail,<i> Pila ovata</i>, from Obazuwa in Edo State, Nigeria

The African apple snail, Pila ovata, is a common local delicacy in the southern regions of Nigeria but little information is available on their parasite fauna. In this investigation, P. ovata collected from a freshwater pond in Obazuwa in Edo State, Nigeria, were screened for parasites. Xiphidio cercariae and sporocysts collected from infected snails were molecularly characterized using partial large sub-units of ribosomal DNA. Phylogenetic reconstruction based on the sequenced data indicated that the parasite belonged to an un-described genus/family within the super family Microphalloidea of digenetic trematodes. Future lifecycle elucidation studies will attempt to describe adult stages of the parasite, identify its definitive host and investigate its possible zoonotic importance.Keywords: Apple snail; Edo State; LSU rDNA; Microphalloidea; xiphidiocercariae.

Behavioural modification of personality traits: testing the effect of a trematode on nymphs of the red damselfly Xanthocnemis zealandica.

Research on animal personality is increasingly demonstrating that individuals in a population are characterised by distinct sets of behavioural traits that show consistency over time and across different situations. Parasites are known to alter the behaviour of their hosts, although their role in shaping host personality remains little studied. Here, we test the effect of trematode infection on two traits of their host's personality, activity and boldness, in nymphs of the red damselfly Xanthocnemis zealandica. Genetic analyses indicate that the undescribed trematode species falls within the superfamily Microphalloidea. Results of laboratory behavioural tests indicate that the two behavioural traits are related to each other: bolder individuals also show higher levels of spontaneous activity than shy ones. However, parasite infection had no effect on either of these behaviours or on their repeatability over three separate testing sessions. Although our findings suggest that this trematode does not influence personality traits of the damselfly host, it remains possible that other standard personality traits not tested here (exploratory tendency, aggressiveness) are affected by infection.

The systematic position and structure of the genus Leyogonimus Ginetsinskaya, 1948 (Platyhelminthes: Digenea) with comments on the taxonomy of the superfamily Microphalloidea Ward, 1901

The systematic position, phylogenetic relationships and composition of the genus Leyogonimus Ginetsinskaya, 1948 have always been uncertain. In the present study, we investigate the taxonomic position and phylogenetic relationships between the type-species L. polyoon (Linstow, 1887) and L. postgonoporus (Neiland, 1951) (previously classified as Macyella), based on newly obtained partial sequences of the nuclear large ribosomal subunit DNA. To test some of the previously proposed systematic arrangements, we have also sequenced specimens of Stomylotrema vicarium Braun, 1901 and Phaneropsolus sp. Our results clearly demonstrate that both L. polyoon and L. postgonoporus belong to the family Pleurogenidae Looss, 1899 within the superfamily Microphalloidea. Thus, the Leyogonimidae Dollfus, 1951 should be recognized as a synonym of the Pleurogenidae. Leyogonimus polyoon clearly constitutes a separate, sister branch to the clade consisting of Collyricloides massanae Vaucher, 1969 and L. postgonoporus. Based on these results, we resurrect the genus Macyella Neiland, 1951 with type-species M. postgonoporus. Besides, Collyricloides Vaucher, 1968 is synonymized with Macyella resulting in new combination Macyella massanae (Vaucher, 1968) comb. nov. Molecular phylogenetic analysis has demonstrated the lack of a close phylogenetic relationships between Stomylotema vicarium and Leyogonimus previously placed by several authors into the family Stomylotrematidae Poche, 1925. The status of the Phaneropsolidae Mehra, 1935 as independent family was confirmed with the addition of the newly sequenced Phaneropsolus sp. from China.

Phylogenetic relationships and systematic position of the families Cortrematidae and Phaneropsolidae (Platyhelminthes: Digenea)

The systematic position and phylogenetic relationships of the family Cortrematidae Yamaguti, 1958 have always been controversial. In the present study, the phylogenetic relationships of this family and its constituent genera and families within the superfamily Microphalloidea were evaluated using previously published and newly obtained sequences of 28S rDNA of Cortrema magnicaudata (Bykhovskaya-Pavlovskaya, 1950) (Cortrematidae), Phaneropsolus praomydis Baer, 1971 and Microtrema barusi Sitko, 2013 (Phaneropsolidae). Results clearly demonstrate that the genus Cortrema Tang, 1951 is closest to Gyrabascus Macy 1935, both genera forming one of the clades within the family Pleurogenidae in the superfamily Microphalloidea and sharing several important morphological features. Thus, the family Cortrematidae should be considered among synonyms of the Pleurogenidae. Based on the analysis of morphology, C. corti Tang, 1951, C. testilobata (Bykhovskaya-Pavlovskaya, 1953) and C. niloticus Ashour, Ahmed et Lewis, 1994 are considered junior synonyms of C. magnicaudata. The phylogenetic position of P. praomydis as a family-level branch not showing close relationships with other families of the Microphalloidea, supports the status of the Phaneropsolidae as an independent family. The genus Parabascus Looss, 1907 previously considered within the Phaneropsolidae clearly belongs to the Pleurogenidae. In addition, the molecular phylogeny has demonstrated that the recently described phaneropsolid Microtrema barusi belongs to the microphallid genus Microphallus Ward, 1901. Therefore, Microtrema Sitko, 2013 is considered a junior synonym of Microphallus. Our analysis has also confirmed the status of Collyriclidae as a family within the Microphalloidea. Not yet sequenced representatives of other families within the Microphalloidea (e.g. Anenterotrematidae, Eumegacetidae, Renschtrematidae, Stomylotrematidae, etc.) need to be included in future molecular phylogenetic studies to better unravel the taxonomic structure and content of this diverse digenean superfamily.

Ultrastructural features of the spermatozoon and its differentiation in Brandesia turgida (Brandes, 1888) (Digenea, Microphalloidea, Pleurogenidae).

Spermatological characters of the digenean Brandesia turgida (Brandes, 1888), an intestinal parasite of the frog Pelophylax ridibundus (Pallas, 1771), have been investigated by means of transmission electron microscopy for the first time. The process of the spermatozoon formation begins with the appearance of the differentiation zone bordered by cortical microtubules and containing two centrioles associated with striated rootlets and with an intercentriolar body. The intercentriolar body is made up of seven distinct electron-dense plates, two less electron-dense, and four electron-lucent zones. The orthogonal development of the two flagella is followed by a flagellar rotation and their proximodistal fusion with the median cytoplasmic process. This process is accompanied by an extension of both the mitochondrion and nucleus into the median cytoplasmic process. The mature spermatozoon of B. turgida contains two parallel axonemes of unequal lengths with the 9 + "1" trepaxonematan pattern, mitochondrion, nucleus, parallel cortical microtubules, four electron-dense attachment zones, an external ornamentation of the plasma membrane, and electron-dense glycogen granules. The anterior extremity of the male gamete contains one complete centriole, a small component of the central element of the second centriole, and peripheral cortical microtubules (up to 45). The posterior extremity of the mature spematozoon exhibits tubular elements of the disorganized axoneme. The present study provides the first data on spermiogenesis within the family Pleurogenidae. Variations of the spermatozoa ultrastructural characters within Digenea, in particular, between different families of the superfamily Microphalloidea, are discussed.

Molecular phylogenetic characterization of Collyriclum faba with reference to its three host-specific ecotypes

Collyriclum faba (Bremser in Schmalz, 1831) is a monostome digenetic trematode with unknown life cycle. On its definitive bird host, C. faba occurs in pairs within a subcutaneous cyst, the location of which on the host body is the base for differentiating three ecotypes of C. faba. Here we examined the hypothesis connecting strong host-specificity of the ecotypes with the possible existence of cryptic speciation among C. faba. Analysis of conserved nuclear ribosomal DNA regions rejected the cryptic speciation hypothesis. Analyses of the variable ITS1 and ITS2 regions revealed that, despite some differentiation between the ecotypes, several large-scale indels occur in multiple ecotypes. Individuals from multiple cysts affecting each host individual differed in their ITS1 sequences, suggesting the individuals infecting a single host did not have common parents. Since we were the first to sequence C. faba, we attempted to verify its position in the current taxonomic system (Plagiorchiida: Gorgoderoidea). We found that C. faba segregates with the superfamily Microphalloidea (in order of maximum likelihood phylogeny: Prosthogonimidae, Pleurogenidae and Microphallidae) instead of any species of the superfamily Gorgoderoidea, as proposed in the past. The results necessitate reclassification of the family Collyriclidae as a member of Microphalloidea.

Molecular phylogenetic analysis of the Microphalloidea Ward, 1901 (Trematoda: Digenea).

Phylogenetic interrelationships of 32 species belonging to 18 genera and four families of the superfamily Microphalloidea were studied using partial sequences of nuclear lsrDNA analysed by Bayesian inference and maximum parsimony. The resulting trees were well resolved at most nodes and demonstrated that the Microphalloidea, as represented by the present data-set, consists of three main clades corresponding to the families Lecithodendriidae, Microphallidae and Pleurogenidae + Prosthogonimidae. Interrelationships of taxa within each clade are considered; as a result of analysis of molecular and morphological data, Floridatrema Kinsella & Deblock, 1994 is synonymised with Maritrema Nicoll, 1907, Candidotrema Dollfus, 1951 with Pleurogenes Looss, 1896, and Schistogonimus Lühe, 1909 with Prosthogonimus Lühe, 1899. The taxonomic value of some morphological features, used traditionally for the differentiation of genera within the Lecithodendriidae and Prosthogonimidae, is reconsidered. Previous systematic schemes are discussed from the viewpoint of present results, and perspectives of future studies are outlined.