Sucker Ratio Research Articles

Uncovering further diversity of Ochoterenatrema Caballero, 1943 (Digenea: Lecithodendriidae) in South American bats

Ochoterenatrema Caballero, 1943 is a genus of lecithodendriid digeneans that prior to this study included 8 species parasitic in bats in the Western Hemisphere. Species of Ochoterenatrema possess a unique morphological feature in form of the pseudogonotyl on the sinistral side of the ventral sucker. In this study, we describe 2 new species of Ochoterenatrema from bats in Ecuador. The new species are readily differentiated from their congeners by a combination of morphological characters, including the distribution of vitelline follicles, length of oesophagus, sucker ratio and the body shape, among other features. We have generated partial nuclear 28S rDNA and mitochondrial cox1 gene DNA sequences from both new species. The newly obtained sequences were used to differentiate among species and study the phylogenetic interrelationships among Ochoterenatrema spp. The internal topology of the clade was weakly supported, although the cox1 tree was much better resolved than the 28S tree. Comparison of sequences revealed 0–1.2% interspecific divergence in 28S and 3.3–20.5% interspecific divergence in cox1 among Ochoterenatrema spp. The new findings demonstrate that bats in South America likely harbor multiple additional undescribed species of Ochoterenatrema. More extensive sampling from broader geographic and host ranges, especially in North America, should allow for a better understanding of the evolution of host associations and morphological traits of this lineage of lecithodendriid digeneans.

Description of Saccocoelioides miguelmontesi n. sp. (Digenea: Haploporidae) from characid fishes in the Iguazu River Basin based on morphological and molecular evidence.

Here we describe a new species of the genus Saccocoelioides found parasitizing Astyanax dissimilis Garavello & Sampaio, Psalidodon bifasciatus (Garavello and Sampaio) and Bryconamericus ikaa Casciotta, Almirón & Azpelicueta from the Iguazu National Park, Misiones province, Argentina. Saccocoelioides miguelmontesi n. sp. was studied based on morphological and molecular (28S rDNA and COI mtDNA sequences) data. The COI mtDNA tree indicated that the specimens collected from the three fish hosts are conspecific, with an intragroup p-distance of 0%. The new species shows an intermediate morphological configuration between the diminutive and robust forms described for Saccocoelioides by Curran (2018). Although, in the 28S rDNA tree, it is placed in a well-supported clade with the two robust species analysed (S. elongatus and S. magnus; p-distance of 1 and 2%, respectively), it differs from the robust group by the range of body size, mature egg size, oral and ventral sucker size, sucker ratio, oral sucker to pharynx ratio, and post-cecal or post-testis/body length percentage. Our results led us to redefine the robust group as having eggs shorter or equal in length to the pharynx. Saccocoelioides miguelmontesi n. sp. the 10th species reported from Argentina and the 7th species within the robust group.

Amphimerus lancea as a Potential Etiological Agent of Human Amphimerosis in South America: A Morphological Analysis Based on Literature Data.

Despite recent advances in the study of amphimerosis, aspects related to the taxonomy of the opisthorchiid species involved in human infection in Ecuador are not completely known. In the present study, previous morphological descriptions of Amphimerus sp. found in human beings and animals from Ecuador were re-studied, aiming to the identification of the parasite. The morphological traits and measures of isolates ofAmphimerus from Ecuadorian foci of transmission previously reported by different authors were critically analyzed and used to achieve the specific identification of the parasite. Morphological and morphometric data, including measures of structures, ratio between suckers, and disposition of vitellaria, were used for taxonomic identification based on taxonomic keys, reviews, and descriptive works. The morphological study based on literature data reveals that Amphimerus lancea (Diesing, 1850) is a species potentially involved in human amphimerosis in Ecuador. The main characteristics here used for differential diagnoses of this species is the larger size of the ventral sucker, which results in an oral sucker/ventral sucker ratio in isolates here considered as A. lancea (1.8-2.7) higher than those verified in other seven species of the genus Amphimerus reported in South America (0.5-1.3). The relative space that the ventral sucker occupies in relation to body width (at the level of ventral sucker) is also greater in A. lancea (49-64% vs 15-38%). Amphimerus lancea is at least one of the species involved in human amphimerosis in Ecuador. The parasite distribution and animal reservoirs are updated and the possibility of new areas of occurrence of human diseases in South America is highlighted. Future integrative taxonomic studies using material properly fixed is encouraged, which can corroborate the morphological identification here achieved and result in progress in the complex taxonomy of Amphimerus spp.

Morphological and molecular evidence reveals a new species of Lyperosomum Looss, 1899 (Digenea: Dicrocoeliidae) from Melanerpes aurifrons (Wagler, 1829) from northern Mexico.

A new species of the genus Lyperosomum Looss, 1899, from the intestine of the golden-fronted woodpecker (Melanerpes aurifrons) from northern Mexico is described. Lyperosomum cuauhxinqui sp. n. is morphologically distinguished from other congeneric species from the Americas by a higher oral/ventral sucker ratio and its body length and width. The sequences of domains D1-D3 of the large subunit (LSU) of nuclear ribosomal DNA and cytochrome c oxidase subunit 1 (cox 1) from the mitochondrial DNA of the new species were obtained and compared with available sequences from GenBank. The genetic divergence estimated between the new species and other congeneric species ranged from 2 to 6% and 13.4 to 17.3% for LSU and cox 1, respectively. Phylogenetic analyses based on the two (LSU and cox 1) molecular markers consistently showed that L. cuauhxinqui sp. n. was nested within the genus Lyperosomum, with strong bootstrap support (100%) and Bayesian posterior probabilities (1.0). In particular, the LSU tree indicated that the sequence of the new species is closely related to sequences from Zonorchis alveyi, Zonorchis delectans and Zonorchis sp. from Central America, suggesting that these sequences should be transferred to the genus Lyperosomum. The new species represents the first record from Mexico and the fifth species identified in the Americas. Our study also revealed that the taxonomy of the genus Lyperosomum should be re-examined by combining molecular, morphological and ecological characteristics.

Two new species of Bacciger Nicoll, 1914 (Trematoda: Faustulidae) in species of Herklotsichthys Whitley (Clupeidae) from Queensland waters.

Two new species of Bacciger Nicoll, 1914 (Faustulidae) are described infecting clupeids collected from the waters off Queensland, Australia; Bacciger minor n. sp. is described from Herklotsichthys castelnaui (Ogilby) in Moreton Bay, southern Queensland and Bacciger major n. sp. is described from Herklotsichthys quadrimaculatus (Rüppell) collected off Lizard Island, on the northern Great Barrier Reef. The two species both differ from previously described species of Bacciger in the combination of their generally elongate bodies, an entire rather than deeply lobed ovary, vitelline follicles that reach to at least the intestinal bifurcation, instead of restricted to further posteriorly but principally distributed in the hindbody, and intestinal caeca extending posteriorly well past the ventral sucker. The two new species have non-overlapping size ranges and differ in their sucker ratios, the distribution of the vitelline follicles and in the shape of the cirrus-sac. ITS2 and 28S rDNA sequence data distinguish the two new species unambiguously. Phylogenetic analysis of available 28S data show they are most closely related to Pseudobacciger cheneyae Sun, Bray, Yong, Cutmore & Cribb, 2014, also recorded off Lizard Island. These are the first faustulids reported from species of Herklotsichthys Whitley, but overall members of the Clupeidae undoubtedly harbours the richest faustulid fauna of any fish family. Baccigeroides ovatus (Price, 1934) n. comb. is proposed for Bacciger ovatus (Price, 1934) Bray & Gibson, 1980 (syn. B. opisthonema Nahhas & Cable, 1964) based on the position of the genital pore being far anteriorly removed from the ventral sucker.

Three new species of Plagioporus Stafford, 1904 from darters (Perciformes: Percidae), with a redescription of Plagioporus boleosomi (Pearse, 1924) Peters, 1957.

A form of Plagioporus Stafford, 1904 is described from the intestine of three North American species of darters (Perciformes: Percidae) from River West Twin, Wisconsin, USA, that we consider to be conspecific with Plagioporus boleosomi (Pearse, 1924) Peters, 1957 based on similarities in the sucker ratio, extent of the forebody, shape and position of the testes, vitellarium distribution and terminal genitalia. Three new species of Plagioporus are described from the intestine of darters as follows: Plagioporus fonti n. sp. from Percina nigrofasciata Agassiz in Florida, USA, Plagioporus limus n. sp. from Etheostoma squamosum Distler in Arkansas, USA and Plagioporus aliffi n. sp. from Etheostoma blennioides newmanni Miller in Arkansas, USA. Morphologically Plagioporus fonti n. sp., Plagioporus limus n. sp. and Plagioporus aliffi n. sp. are most similar to one another and to P. boleosomi, Plagioporus lepomis Dobrovolny, 1939 and 'P. etheostomae', a nomen nudum for a species described from Etheostoma blennioides Rafinesque in Kentucky, USA, all of which are collectively distinguished from congeners in having a combination of confluent vitellarium in the post-testicular space and absence of vitelline follicles with their entire length distributed in the forebody. Plagioporus fonti n. sp., P. limus n. sp. and P. aliffi n. sp. are respectively distinguished from one another and their closest congeners in having the anterior extent of the vitellarium in the anterior half of forebody to slightly anterior to the ventral sucker as opposed to one approximately at the level of the posterior margin of the ventral sucker, possession of an excretory vesicle reaching the anterior testis as opposed to one only reaching the posterior testis and having a longer than wide oral sucker and a wider than long ventral sucker. A Bayesian inference (BI) analysis of partial 28S rDNA sequences was conducted using the three new species and 24 sequences of opecoelids retrieved from GenBank, including ten species of Plagioporus. Plagioporus aliffi n. sp., Plagioporus fonti n. sp. and P. boleosomi comprised a moderately supported sister group to a clade containing all species of Plagioporus except Plagioporus limus n. sp. and Plagioporus shawi (Mcintosh, 1939) Margolis, 1970. Plagioporus limus and in turn P. shawi were resolved as sister to all other congeners with high and moderate support, respectively.

Neopsilotrema n. g. (Digenea: Psilostomidae) and three new species from ducks (Anseriformes: Anatidae) in North America and Europe.

Neopsilotrema n. g. (Digenea: Psilostomidae) and three new species of psilostomid digeneans are described from birds in North America and Europe: Neopsilotrema lakotae n. sp. from Aythya americana (Eyton) in North Dakota, USA, Neopsilotrema affine n. sp. from Aythya affinis (Eyton) in Minnesota, USA and Neopsilotrema lisitsynae n. sp. from Anas crecca L. in Kherson Region, Ukraine. Neopsilotrema n. g. shares a bipartite seminal vesicle with only three genera within the Psilostomidae, Psilotornus Byrd & Prestwood, 1969, Psilostomum Looss, 1899 and Grysoma Byrd, Bogitsh & Maples, 1961. The new genus differs from Psilotornus in the presence of a muscular pharynx and a massive ventral sucker; the location of the cirrus-sac in relation to the ventral sucker and more posterior location of ovary; the nature of the vitellarium (i.e. comprising large, compact follicles with small vitelline cells vs weakly defined follicles with large vitelline cells); a proportionately shorter forebody; and in parasitisation in anseriform (vs passeriform) birds. Differences between the new genus and Psilostomum comprise the shape of the body, the relative size of the suckers, somewhat longer forebody and a more anterior location of the testes. Neopsilotrema n. g. differs from Grysoma in the relative size of the suckers, the degree of development of prostatic cells, the nature of the vitellarium and the size of the eggs in relation to body length. The European species Neopsilotrema lisitsynae n. sp. is distinguished from its congeners in having a longer, narrower and distinctly more elongate body with a longer post-testicular region and anterior limits of the vitelline fields posterior to ventral sucker. The two North American forms, Neopsilotrema lakotae n. sp. and Neopsilotrema affine n. sp., are cryptic species with largely overlapping metrical data; these are distinguished by comparing genetic data. The phylogenetic hypotheses for the Psilostomidae developed from sequence data analyses based on partial 28S rDNA support the erection of the new genus and the distinction of the three new species. Grysoma marilae (Price, 1942) agrees more closely with the generic diagnosis of Neopsilotrema, especially in relation to the size and shape of the body, the relative length of the forebody and post-testicular field, the structure of the vitellarium, the location of the reproductive organs and the sucker ratio. Consequently, it is here transferred to the new genus as Neopsilotrema marilae (Price, 1942) n. comb.

A molecular phylogeny of Asian species of the genus Metagonimus (Digenea)—small intestinal flukes—based on representative Japanese populations

Metagonimus Katsurada, 1912 is a genus of small intestinal parasites. The genus comprises eight species, primarily from far-eastern Asia, with two exceptions reported from Europe. Metagonimus yokogawai, the most widespread species, is the main agent responsible for the intestinal disease, metagonimiasis, in Japan and some other East Asian countries. On the basis of the ratio of the size of the ventral and oral suckers, Metagonimus has traditionally been morphologically divided into two groups; however, the genus has not been extensively studied using molecular data. To reveal phylogenetic relationships within Metagonimus based on molecular data, we analyzed six of the seven species present in Asia using samples collected in central Japan. Maximum likelihood and Bayesian analyses of a combined 28S ribosomal DNA (rDNA), internal transcribed spacer 2 (ITS2), and mitochondrial cox1 gene sequence dataset separated the six species into two well-supported clades. One clade comprised M. yokogawai, M. takahashii, M. miyatai, and M. hakubaensis, whereas the other consisted of M. otsurui and M. katsuradai. Genetic distances calculated from 28S rDNA and ITS2 nucleotide sequences and a comparison of the predicted amino acid sequences of cox1 gene suggested that M. otsurui and M. katsuradai may have diverged recently. None of the four main morphological characters used to delimit species of Metagonimus (i.e., sucker ratio, positions of the uterus and testes, and distribution of vitelline follicles) was consistent with the distribution of species in the molecular tree.

Two new species of Phyllodistomum Braun, 1899 (Digenea: Gorgoderidae), from freshwater fishes (Cyprinodontiformes: Goodeidae: Goodeinae) in central Mexico: An integrative taxonomy approach using morphology, ultrastructure and molecular phylogenetics.

An integrative taxonomy approach is used to characterise the diversity of gorgoderid trematodes that parasitize freshwater fishes of the subfamily Goodeinae in central Mexico. Records of Phyllodistomum sp. and Dendrorchis sp. from the urinary bladder of goodeines have been previously published, although the identification at species level was not achieved. A few specimens were collected and fixed to conduct a scanning electron microscopy study, and to obtain sequences of a mitochondrial (COI) and nuclear (28S rRNA) gene, to be analysed in the context of the molecular phylogeny of gorgoderid trematodes. Based on the new findings, two new species of Phyllodistomum Braun, 1899 are described. Phyllodistomum cribbi n. sp. was found in Zoogoneticus quitzeoensis (Bean), Allotoca zacapuensis Meyer, Radda & Domínguez-Domínguez, Hubbsina turneri de Buen and Z. purhepechus Domínguez-Domínguez, Pérez-Rodríguez & Doadrio from Zacapu Lake, and La Luz Spring, in Michoacan, central Mexico. Phyllodistomum wallacei n. sp. parasitized Xenotaenia resolanae Turner, Ilyodon furcidens (Jordan & Gilbert), and Allodontichthys tamazulae Turner from the Cuzalapa, Ayuquila and Tamazula Rivers in Jalisco, western Mexico. These species are compared with several freshwater Phyllodistomum species from different areas of the world, especially a group of eight species that comprise a monophyletic clade in recent phylogenetic hypotheses of the Gorgoderidae Looss, 1899. The two new species are distinguished from other close relatives by the combination of morphological traits such as the body shape, sucker ratio, shape of the gonads, and extension of intestinal ceca. The new species are distinct in some ultrastructural characters of the body surface when compared with those species where scanning electron micrographs (SEM) and/or microphotographs are available. Data of two molecular markers (28S rRNA and COI genes) demonstrate that the two new species are distinct from each other and from those species of Phyllodistomum Braun, 1899 for which sequences are available.

A new species of Neolebouria Gibson, 1976 (Opecoelidae: Plagioporinae) from the whitecheek monocle bream, Scolopsis vosmeri (Perciformes: Nemipteridae), from the Panjim coast at Goa, with a checklist of parasites previously reported from this fish.

Neolebouria capoori n. sp. (Opecoelidae: Plagioporinae) is described from the whitecheek monocle bream, Scolopsis vosmeri (Bloch) (Perciformes: Nemipteridae) from the Panjim coast on the central west coast of India at Goa. The new species differs from both Neolebouria cantherhini (Li, Qiu & Zhang, 1988) as originally described from Thamnaconus modestus (Günther) (syn. Cantherines modestus Günther ) and Neolebouria confusum (Overstreet, 1969) as originally described from Ocyurus chrysurus (Bloch) by having the cirrus sac surpassing the ventral sucker posteriorly in N. cantherhini and being entirely preacetabular in N. confusum compared to terminating near the midlevel of the ventral sucker in N. capoori n. sp. The new species is most similar to N. confusum, but it further differs from this species by having the vitelline fields terminating near the level of the esophageal bifurcation compared to terminating near the level of the posterior margin of the pharynx, a larger sucker ratio (1:1.7-1:2.0 compared to 1:1.4-1:1.7), a somewhat shorter cirrus sac relative to body length (160-448, representing 9-18% of the body length compared to about 367, representing 22%), and the egg of the new species has a boss at the anopercular end that is not present in N. confusum. This study represents the first report on an opecoelid from S. vosmeri. A review of the parasites reported from S. vosmeri is included.

Two new species of Phyllodistomum Braun, 1899 (Trematoda: Gorgoderidae Looss, 1899) from Great Barrier Reef fishes.

Two new species of Phyllodistomum Braun, 1899 are described from the urinary bladder of fishes of the Great Barrier Reef. Phyllodistomum hoggettae n. sp. is described from Plectropomus leopardus (leopard coralgrouper) (Serranidae) and P. vaili n. sp. is described from Mulloidichthys vanicolensis (yellowfin goatfish) and M. flavolineatus (yellowstripe goatfish) (Mullidae). These species are compared with 26 previously described marine Phyllodistomum species and found to be distinct in combinations of body shape, sucker ratio and shape of the gonads. Preliminary molecular data also demonstrate that they are distinct from each other and for those other species for which data are available.

A New Species ofAuriculostoma(Digenea: Allocreadiidae) in the Mexican TetraAstyanax mexicanus(Actinopterygii: Characidae) from Central Veracruz, Mexico, Described with the Use of Morphological and Molecular Data

Auriculostoma totonacapanensis n. sp. is described from the Mexican tetra, Astyanax mexicanus (Actinopterygii, Characidae) collected in a tributary creek of the Bobos River in Filipinas, Veracruz, Mexico. The new species is set apart from all congeners by the combination of some morphological characters such as the testes position (oblique in most specimens), the ventral to oral sucker ratio (1:1.2 × 1:1.1), the cirrus sac originating at the ovarian region, and by having vitelline follicles not confluent in the posttesticular region. Auriculostoma totonacapanensis n. sp. closely resembles Auriculostoma platense (Szidat, 1954) Scholz, Aguirre-Macedo, and Choudhury, 2004 and Auriculostoma diagonale Curran, Tkach and Overstreet, 2011 by possessing oblique testes; however, it differs from both species by possessing a genital pore located at level of the cecal bifurcation and by having vitelline follicles extending anteriorly up to the cecal bifurcation level, instead of a genital pore located between the anterior margin of the ventral sucker and cecal bifurcation, and vitelline follicles extending anteriorly to the mid level of the esophagus as in A. platense or to the pharynx level as in A. diagonale. Additionally, the new species differs from A. diagonale by having vitelline follicles not confluent or scarcely confluent in the posttesticular region rather than extensively confluent. Scanning electron microscopy micrographs of the new species demonstrated the presence of a single pair of muscular lobes on either side of the oral sucker, with a broad base, stretching from the ventrolateral to the dorsolateral side. Maximum parsimony and Bayesian inference analyses of the 28S rRNA gene sequences placed A. totonacapanensis as sister species of Auriculostoma astyanace Scholz, Aguirre-Macedo, and Choudhury, 2004 . Nucleotide variation between A. totonacapanensis and A. astyanace was 2.0% and 3.6% for the 28S rRNA gene and ITS2 sequences, respectively. Sequence variation for the 28S rRNA gene between Auriculostoma spp. and 7 other genera of Allocreadiidae ranged from 2.4 to 6.3%.

Digenetic trematodes from siganid fish Amphacanthus sigan at Macady Bay, Southern Hurghada, Red Sea, Egypt

Forty fish samples of Amphacanthus sigan were collected from Sharm El-Naga southern Hurghada to study the parasitic infection included and present a new individual to Helicometra species using light microscope and re-describe another digenean trematode species using scanning electron microscope (SEM). Two trematode species were identified and described; Helicometra siganus n. sp. Nov belonging to Helicometra Odhner, 1902 (family Opecoelidae Ozaki, 1925) which is different from all the listed species in many features as having an elongated body, tapering anteriorly and larger sucker ratio; the vitellaria extended from the intestinal bifurcation to the posterior extremity of the hind-body and finally the cirrus sac and cirrus longer than the other species and extended to the midpoint of esophagus level. So, these criteria are specific and sufficient to consider it as a new species. The other species, Gyliauchen volubilis Nagaty, 1956 (Gyliauchenidae Fuki, 1929 and Ozaki, 1933) which was described before but some other constituent are not evident and appeared using the electron microscope. However, the present sample illustrated transverse striations on the body surface, the acetabulum evaginates outward, ovoid shaped and surrounded by lip-like structures and finally, the excretory pore is situated at some distance from the acetabulum at the posterior end extremity.

Morphological and molecular characterization of Lecithochirium grandiporum (Digenea: Hemiuridae) infecting the European eel Anguilla anguilla as a new host record in Egypt

In the present study, the morphological and molecular characterization of Lecithochirium grandiporum, a digenetic trematode infecting the European eel Anguilla anguilla (Family (F): Anguillidae), were described for the first time from Burullus Lake, Kafr El-Sheikh Governorate, Egypt. Twenty-five out of 60 specimens (infection rate of 41.66%) were found to be naturally infected. Infection was recorded as small worms attached to the inner wall of the intestine of host fish. Adult worms measured 1.59 ± 0.20 (1.3-1.85) mm long and 0.3 ± 0.02 (0.29-0.48) mm wide for everted specimens with a smaller oral sucker measuring 0.15 ± 0.02 (0.13-0.18) mm, and a larger ventral sucker which was 0.16 ± 0.02 (0.14-0.25) mm. Our results recorded morphological differences as smaller dimensions of different body parts and the smaller oral/ventral sucker ratio between Lecithochirium fusiforme and L. grandiporum. Also, the phylogenetic position of the worm was determined by molecular characterization of their 18 SSU rDNA. Results were compared with those of previously recorded species on the Gene Bank. It was found that the present species coincide with those belonging to genus Lecithochirium. Comparison of the nucleotide sequences and divergence showed that the SSU rDNA gene of this Lecithochirium species revealed 92 % sequence identity with L. fusiforme (accession no. DQ413192) differing in 26 nucleotides with lower divergence value. According to these results, this study indicated that the present species is recorded as L. grandiporum with accession no. KC166146 as a parasite with new host and locality records in Egypt.

Lecithostaphylus tylosuri sp. nov. (Digenea, Zoogonidae) from the digestive tract of the needlefish Tylosurus acus imperialis (Teleostei, Belonidae)

Lecithostaphylus tylosuri sp. nov. (Digenea, Zoogonidae) specimen were collected from the digestive tract of Tylosurus acus imperialis (Teleostei, Belonidae) caught off the eastern coast of Tunisia. L. tylosuri is very similar to its closest relatives, L. retroflexus and L. nitens. It can be easily distinguished from L. retroflexus (Molin, 1859) in having a more extensive vitellarium, with follicles reaching from the posterior margin of the acetabulum and extending beyond the posterior margin of the testes and a coiled seminal vesicle. L. tylosuri differs from L. nitens as illustrated by Linton 1898, in having a longer cirrus pouch (0.7 mm vs 0.36 mm, respectively) overlapping the anterior edge of the ventral sucker and a submarginal genital pore (submedian in L. nitens). It's also different from L. nitens as described by Manter 1947 in the vitelline disposition and in having the greater sucker ratio (1: 1.3-2.1 vs 1: 1.3-1.6, respectively). L. tylosuri differs from L. nitens as reported by Machida and Kuramochi 2000 by the absence of variations in the vitellarium disposition in all specimens. L. tylosuri is more similar to L. nitens from group A (considered synonym of L. ahaaha Yamaguti, 1970 = L. nitens by Bray 1987) by having vitelline follicles extending beyond the testes. L. tylosuri can be distinguished from L. ahaaha by its pedunculate rather than prominent acetabulum and its larger body size (4.10-7.85 mm long and 0.75-1.2 mm large vs 2.1-6 mm long and 0.45-1.1 mm large, respectively). The prevalence of L. tylosuri sp. nov. was negatively correlated with host length (decreasing with host size increasing). Host sex does not seem to affect infection parameters.

Description of a New Opecoelid Trematode Species from Nototheniid Fish in the Beagle Channel (Sub-Antarctica)

Macvicaria magellanica n. sp. (Digenea: Opecoelidae) is the third representative of this genus occurring in fish in the Magellanic sub-region of sub-Antarctica and the first one found in sub-coastal waters in this area (the Beagle Channel). Its main taxonomic features include an elongate body, oral:ventral sucker ratio based on widths of 1.0:1.52-1.98, cirrus sac reaching to level of posterior half of the ventral sucker, testes arranged in tandem, numerous vitelline follicles divided into 2 groups separated by a gap parallel to the ventral sucker, vitelline follicles dorsally not confluent at the uterus and gonads, and egg dimensions of 40-51 × 25-32 μm. The most similar species is Macvicaria antarctica, but it differs from the newly described species in having vitelline follicles dorsally confluent at the level of the uterus and by occurring in fish associated with the Falkland-Patagonian shelf at greater depths (at the North Scotia Ridge, 300-500 m). A key to 9 Antarctic and sub-Antarctic species of Macvicaria is included.

New species of Haematoloechus (Digenea: Plagiorchidae) in the lung of the foothill yellow-legged frog Rana boylii (Anura), from Humboldt County, California, USA

A new species of Haematoloechus is described from the lungs of Rana boylii from Humboldt County, California. The new species is similar to Haematoloechus buttensis, Haematoloechus kernensis, and Haematoloechus complexus in general course of the uterus and gonad shape. It is similar to H. buttensis by having a cirrus sac terminating midway between the posterior margin of the pharynx and the anterior margin of the ovary, and having a smaller oral/ ventral sucker ratio; to H. complexus by having the genital pore ventral to the pharynx, and it is similar to H. kernensis by having a larger oral sucker to pharynx width ratio. The new species is unique by lacking an extra-cecal longitudinal uterine loop from the hind-body. Molecularly, the new species differs 1.04–1.15% in partial 28S sequence with respect to H. complexus, and a monophyletic grouping of these specimens in a phylogenetic analysis of all available sequence data consistent with the species-specific status proposed herein. Evidence is also presented to suggest that specimens identified as H. buttensis in Rana pretiosa from British Columbia, Canada represents a new, but still undescribed species. The importance of conducting biological inventories of helminths, along with continued monitoring of populations, and collections based taxonomy are related.

A new gorgoderid trematode of the genus Phyllodistomum (Digenea: Gorgoderidae) from Clarias gariepinus (Actinopterygii: Clariidae) in Lake Tana, Ethiopia

Phyllodistomum tana sp. nov. is described from the ureters of Clarias gariepinus from Lake Tana, Ethiopia. This species is distinguished from its congeners in Africa in having an oblong body shape, transverse loops of the uterus between the posterior margin of ventral sucker and the vitelline follicles, and the localization exclusively in the ureters of C. gariepinus. The new species differs from P. bavuri and P. vanderwaali in the larger size of body, the position of the testes with respect to the ovary and with each other, the lobed vitelline follicles and the sucker ratio.

Discovery ofParvatrema duboisiandParvatrema homoeotecnum(Digenea: Gymnophallidae) from Migratory Birds in Korea

Adult worms of Parvatrema spp. (Digenea: Gymnophallidae) were found in the intestines of 2 species of migratory birds, i.e., a great knot, Calidris tenuirostris, and 2 Mongolian plovers, Charadrius mongolus, in the coastal area of Gunsan-si, Jeollabuk-do in October 2009. The recovered Parvatrema worms were 79 in total number and composed of 2 species. The worms from a great knot were 289 µm in length with the oral and ventral sucker ratio of 2 : 1. They had a single vitellarium, and their intrauterine eggs were 25.0 x 17.5 µm in size. These findings were compatible with P. duboisi (Dollfus, 1923) Bartoli, 1974 (syn. P. timondavidi Bartoli, 1963). The worms recovered from the Mongolian plovers were smaller in length than P. duboisi and had 2 vitellaria. The oral and ventral sucker ratio was 2.5:1, and the eggs were 17.5 x 8.8 µm in size. These worms were assigned to be P. homoeotecnum James, 1964. This is the first report on the natural final hosts of Parvatrema spp. in Korea.

Re-evaluation of the species composition of Bashkirovitrema Skrjabin, 1944 (Digenea: Echinostomatidae), with the description of two new species of this genus and the proposal of Kostadinovatrema novaeguiniense n. g., n. sp.

A comparison of specimens previously identified as Bashkirovitrema incrassatum (Diesing, 1850) from the African or cape clawless otter Aonyx capensis, and the speckle-throated or spotted-throated otter Hydrictis maculicollis from the Old World with specimens and descriptions of B. incrassatum from the New World showed that those from Africa (Bashkirovitrema africanum n. sp.) had a more extensive distribution of the vitelline fields than either B. canadense n. sp. from the northern river otter Lontra canadensis and the American mink Neovison vison (North America) and B. incrassatum from the Neotropical river otter Lontra longicaudis (South America). B. africanum n. sp. further differs from B. canadense n. sp. by having a smaller body, shorter forebody, smaller oral sucker, longer cirrus, shorter intertesticular space, shorter post-testicular space and longer eggs. B. canadense n. sp. can be distinguished from B. incrassatum by having a longer body, longer forebody, smaller sucker ratio, smaller testes, greater distance between the ventral sucker and the ovary, shorter cirrus-sac, longer post-testicular space and narrower eggs. B. africanum n. sp. differs from B. incrassatum by having a smaller ventral sucker, larger ovary, shorter cirrus-sac, smaller intertesticular space, larger post-testicular space and longer eggs that are not as wide. Kostadinovatrema n. g., as represented by K. novaeguiniense n. sp., can be separated from species of Bashkirovitrema Skrjabin, 1944 by having a wider body width to length profile, a head collar that is narrower than the forebody and armed with 33 rather than 27 collar spines, an ovary that is further removed anteriorly from the testes, and a dorso-ventrally flattened hindbody that is nearly as broad as the forebody. The new genus differs from Hypoderaeum Dietz, 1909 and Moliniella Hübner, 1939 by having 33 head collar spines.