Description and Phylogenetic Relationships of Anhingatrema n. gen. (Digenea: Diplostomidae) with Two New Species from New World Anhingas (Aves: Anhingidae)

PURPOSE

The Diplostomidae is a globally distributed family of digeneans that parasitize a wide variety of tetrapod definitive hosts. Recent molecular phylogenetic studies have revealed unknown diplostomid diversity in avian hosts throughout the New World. Herein, we provide descriptions of a novel genus of diplostomids with two new species.

METHODS

Two species of diplostomids belonging to the new genus were collected from anhinga birds in Mississippi (USA) and Brazil. Partial nuclear 28S ribosomal and mitochondrial cox1 genes were sequenced. Ribosomal data were used for phylogenetic inference.

RESULTS

Both species of Anhingatrema n. gen. were positioned in a 100% supported, monophyletic clade in the phylogenetic tree. The molecular phylogenetic position and a combination of morphological features (e.g., presence of pseudosuckers, testes shape and orientation) supported erection of the new genus. Anhingatrema overstreeti n. sp. and Anhingatrema cararai n. sp. are morphologically similar, but differ in size of and ratios associated with pseudosuckers. The two species differ by 2% of 28S sequences and 13.8% of cox1 sequences. Comparison of DNA sequences revealed that Diplostomidae gen. sp. in GenBank (MZ314151) is conspecific with An. overstreeti n. sp.

CONCLUSION

Anhingatrema n. gen. is the sixth genus of diplostomids known from anhingas worldwide. Anhingatrema cararai n. sp. is the first diplostomid to be reported from anhingas in South America. Combined with previous studies, the molecular phylogenies revealed at least two host switches to anhingas from other birds during the evolutionary history of the Diplostomidae.

Molecular phylogeny supports invalidation of Didelphodiplostomum and Pharyngostomoides (Digenea: Diplostomidae) and reveals a Tylodelphys from mammals

Alaria, Didelphodiplostomum and Pharyngostomoides are among genera of diplostomid digeneans known to parasitize mammalian definitive hosts. Despite numerous recent molecular phylogenetic studies of diplostomids, limited DNA sequence data is available from diplostomids parasitic in mammals. Herein, we provide the first 28S rDNA and cox1 mtDNA sequences from morphologically identified, adult specimens of Didelphodiplostomum and Pharyngostomoides. Newly generated 28S sequences were used to infer the phylogenetic interrelationships of these two genera among other major lineages of diplostomoideans. The phylogeny based on 28S and a review of morphology clearly suggests that Pharyngostomoides should be considered a junior synonym of Alaria, while Didelphodiplostomum should be considered a junior synonym of Tylodelphys. Pharyngostomoides procyonis (type species), Pharyngostomoides adenocephala and Pharyngostomoides dasyuri were transferred into Alaria as Alaria procyonis comb. nov., Alaria adenocephala comb. nov. and Alaria dasyuri comb. nov.; Didelphodiplostomum variabile (type species) and Didelphodiplostomum nunezae were transferred into Tylodelphys as Tylodelphys variabilis comb. nov. and Tylodelphys nunezae comb. nov. In addition, Alaria ovalis comb. nov. (formerly included in Pharyngostomoides) was restored and transferred into Alaria based on a morphological study of well-fixed, adult specimens and the comparison of cox1 DNA sequences among Alaria spp. The diplostomid genus Parallelorchis was restored based on review of morphology.

Molecular phylogenetic analysis of Neodiplostomum and Fibricola (Digenea, Diplostomidae) does not support host-based systematics

Fibricola and Neodiplostomum are diplostomid genera with very similar morphology that are currently separated based on their definitive hosts. Fibricola spp. are normally found in mammals, while Neodiplostomum spp. typically parasitize birds. Previously, no DNA sequence data was available for any member of Fibricola. We generated nuclear ribosomal and mtDNA sequences of Fibricola cratera (type-species), Fibricola lucidum and 6 species of Neodiplostomum. DNA sequences were used to examine phylogenetic interrelationships among Fibricola and Neodiplostomum and re-evaluate their systematics. Molecular phylogenies and morphological study suggest that Fibricola should be considered a junior synonym of Neodiplostomum. Therefore, we synonymize the two genera and transfer all members of Fibricola into Neodiplostomum. Specimens morphologically identified as Neodiplostomum cratera belonged to 3 distinct phylogenetic clades based on mitochondrial data. One of those clades also included sequences of specimens identified morphologically as Neodiplostomum lucidum. Further study is necessary to resolve the situation regarding the morphology of N. cratera. Our results demonstrated that some DNA sequences of N. americanum available in GenBank originate from misidentified Neodiplostomum banghami. Molecular phylogentic data revealed at least 2 independent host-switching events between avian and mammalian hosts in the evolutionary history of Neodiplostomum; however, the directionality of these host-switching events remains unclear.

Unravelling the diversity of the Crassiphialinae (Digenea: Diplostomidae) with molecular phylogeny and descriptions of five new species

Crassiphialinae Sudarikov, 1960 is a large subfamily of the Diplostomidae Poirier, 1886 with a complex taxonomic history. It includes a diversity of species parasitic in the intestines of avian and mammalian definitive hosts worldwide. Posthodiplostomum Dubois, 1936 is a large and broadly distributed crassiphialine genus notorious for its association with diseases in their fish second intermediate hosts. In this study, we generated partial 28S rDNA and cytochrome c oxidase subunit 1 (cox1) mtDNA gene sequences of digeneans belonging to seven crassiphialine genera. The 28S sequences were used to study the interrelationships among crassiphialines and their placement among other major diplostomoidean lineages. Our molecular phylogenetic analysis and review of morphology does not support subfamilies currently recognized in the Diplostomidae; therefore, we abandon the current subfamily system of the Diplostomidae. Molecular phylogenetic analyses suggest the synonymy of Posthodiplostomum, Ornithodiplostomum Dubois, 1936 and Mesoophorodiplostomum Dubois, 1936; morphological study of our well-fixed adult specimens and review of literature revealed lack of consistent differences among the three genera. Thus, we synonymize Ornithodiplostomum and Mesoophorodiplostomum with Posthodiplostomum. Our phylogenetic analyses suggest an Old World origin of Posthodiplostomum followed by multiple dispersal events among biogeographic realms. Furthermore, our analyses indicate that the ancestors of these digeneans likely parasitized ardeid definitive hosts. Four new species of Posthodiplostomum collected from birds in the New World as well as one new species of Posthodiplostomoides Williams, 1969 from Uganda are described.

Analysis of the fecal microbiome in Kemp’s ridley sea turtles Lepidochelys kempii undergoing rehabilitation

The impact of the intestinal and fecal microbiome on animal health has received considerable attention in recent years and has direct implications for the veterinary and wildlife rehabilitation fields. To examine the effects of rehabilitation on the microbiome in Kemp’s ridley sea turtlesLepidochelys kempii, fecal samples from 30 incidentally captured juveniles were collected during rehabilitation. Samples were analyzed to determine alpha- (α) and beta- (β) diversity as well as the taxonomic abundance of the fecal microbiota during rehabilitation and in response to treatment with antibiotics. The fecal microbial communities of animals housed in rehabilitation for a ‘short-term’ stay (samples collected 0-9 d post-capture) were compared with ‘long-term’ (samples collected 10+ d post-capture) and ‘treated’ groups (samples collected from turtles that had received antibiotic medication). Results of this study indicate that the most dominant phylum in fecal samples wasBacteroidetes(relative abundance, 45.44 ± 5.92% [SD]), followed byFirmicutes(26.62 ± 1.58%),Fusobacteria(19.49 ± 9.07%), andProteobacteria(7.39 ± 1.84%). Similarly, at the family level,Fusobacteriaceae(28.36 ± 17.75%),Tannerellaceae(15.41 ± 10.50%),Bacteroidaceae(14.58 ± 8.48%), andRuminococcaceae(11.49 ± 3.47%) were the most abundant. Our results indicated that both antibiotic-treated and long-term rehabilitated turtles demonstrated a significant decrease in β-diversity when compared to short-term rehabilitated turtles. Our results likewise showed that the length of time turtles spent in rehabilitation was negatively correlated with α- and β-diversity. This study demonstrates the importance of a judicious use of antibiotics during the rehabilitation process and emphasizes the importance of limiting the length of hospital stays for sick and injured sea turtles as much as possible.

Phylogeny and systematics of the Proterodiplostomidae Dubois, 1936 (Digenea: Diplostomoidea) reflect the complex evolutionary history of the ancient digenean group

The Proterodiplostomidae Dubois, 1936 is a relatively small family of diplostomoidean digeneans parasitising the intestines of reptilian hosts associated with freshwater environments in tropical and subtropical regions. The greatest diversity of proterodiplostomids is found in crocodilians, although some parasitise snakes and turtles. According to the most recent revision, the Proterodiplostomidae included 17 genera within 5 subfamilies. Despite the complex taxonomic structure of the family, availability of testable morphology-based phylogenetic hypotheses and ancient hosts, molecular phylogenetic analyses of the group were practically lacking. Herein, we use novel DNA sequence data of the nuclear lsrRNA gene and mitochondrial cox1 gene from a broad range of proterodiplostomid taxa obtained from crocodilian, fish, and snake hosts on four continents to test the monophyly of the family and evaluate the present morphology-based classification system of the Proterodiplostomidae in comparison with the molecular phylogeny. This first detailed phylogeny for the Proterodiplostomidae challenges the current systematic framework. Combination of molecular phylogenetic data with examination of freshly collected quality specimens and re-evaluation of morphological criteria resulted in a number of systematic and nomenclatural changes along with a new phylogeny-based classification of the Proterodiplostomidae. As the result of our molecular and morphological analyses: (i) the current subfamily structure of the Proterodiplostomidae is abolished; (ii) three new genera, Paraproterodiplostomum n. g., Neocrocodilicola n. g. and Proteroduboisia n. g., are described and Pseudoneodiplostomoides Yamaguti, 1954 is restored and elevated from subgenus to genus level; (iii) two new species, Paraproterodiplostomum currani n. g., n. sp. and Archaeodiplostomum overstreeti n. sp., are described from the American alligator in Mississippi, USA. Comparison of the structure of terminal ducts of the reproductive system in all proterodiplostomid genera did not support the use of these structures for differentiation among subfamilies (or major clades) within the family, although they proved to be useful for distinguishing among genera and species. Our study includes the first report of proterodiplostomids from Australia and the first evidence of a snake acting as a paratenic host for a proterodiplostomid. A key to proterodiplostomid genera is provided. Questions of proterodiplostomid-host associations parasitic in crocodilians are discussed in connection with their historical biogeography. Our molecular phylogeny of the Proterodiplostomidae closely matches the current molecular phylogeny of crocodilians. Directions for future studies of the Proterodiplostomidae are outlined.

Molecular phylogeny of the Cyathocotylidae (Digenea, Diplostomoidea) necessitates systematic changes and reveals a history of host and environment switches

The Cyathocotylidae is a globally distributed family of digeneans parasitic as adults in fish, reptiles, birds, and mammals in both freshwater and marine environments. Molecular phylogenetic analysis of interrelationships among cyathocotylids is lacking with only a few species included in previous studies. We used sequences of the nuclear 28S rRNA gene to examine phylogenetic affinities of 11 newly sequenced taxa of cyathocotylids and the closely related family Brauninidae collected from fish, reptiles, birds, and dolphins from Australia, Southeast Asia, Europe, North America and South America. This is the first study to provide sequence data from adult cyathocotylids parasitic in fish and reptiles. Our analyses demonstrated that the members of the genus Braunina (family Brauninidae) belong to the Cyathocotylidae, placing the Brauninidae into synonymy with the Cyathocotylidae. In addition, our DNA sequences supported the presence of a second species in the currently monotypic Braunina. Our phylogeny revealed that Cyathocotyle spp. from crocodilians belong to a separate genus (Suchocyathocotyle, previously proposed as a subgenus) and subfamily (Suchocyathocotylinae subfam. n.). Morphological study of Gogatea serpentum indicum supported its elevation to species as Gogatea mehri. The phylogeny did not support Holostephanoides within the subfamily Cyathocotylinae; instead, Holostephanoides formed a strongly supported clade with members of the subfamily Szidatiinae (Gogatea and Neogogatea). Therefore, we transfer Holostephanoides into the Szidatiinae. DNA sequence data revealed the potential presence of cryptic species reported under the name Mesostephanus microbursa. Our phylogeny indicated at least two major host switching events in the evolutionary history of the subfamily Szidatiinae which likely resulted in the transition of these parasites from birds to fish and snakes. Likewise, the transition to dolphins by Braunina represents another major host switching event among the Cyathocotylidae. In addition, our phylogeny revealed more than a single transition between freshwater and marine environments demonstrated in our dataset by Braunina and some Mesostephanus.

Phylogenetic relationships and systematic position of the enigmatic Urotrema Braun, 1900 (Platyhelminthes: Digenea)

The systematic position of Urotrema Braun, 1900 and the family Urotrematidae Poche, 1926 have always been controversial. Due to its unusual morphological characteristics, lack of knowledge of the life cycle or details of its excretory system, this family was placed within different higher taxonomic groups of digeneans. Despite being one of the most enigmatic digenean families in terms of its phylogenetic affinities, DNA sequence data for Urotrematidae were lacking. Here, we evaluate the phylogenetic relationships of Urotrema using newly obtained partial sequences of the 28S rRNA gene from Urotrema specimens collected in North, Central and South America including the type species U. scabridum Braun, 1900, as well as previously published sequences of digeneans. Our study has demonstrated that Urotrema is phylogenetically closest (100% branch support) to members of Parabascus Looss, 1907 belonging to the family Pleurogenidae Looss, 1899. Thus, the family Urotrematidae becomes a junior synonym of the Pleurogenidae. Urotrema forms a 100% supported clade among the Pleurogenidae, parasitic in warm-blooded vertebrates. However, the phylogenetic relationships and exact systematic position of the remaining 3 genera currently placed in the Urotrematidae remains unclear and requires additional studies as their allocation is mostly based on the terminal posterior position of the genital pore and cirrus-sac. According to our results the genus Parabascus appears to be paraphyletic and requires further detailed phylogenetic and morphological analyses.

Gauging the influence of increased search effort on reporting rates of bottlenose dolphin (Tursiops truncatus) strandings following the deepwater horizon oil spill

The co-occurrence of the Deepwater Horizon oil spill and the northern Gulf of Mexico cetacean Unusual Mortality Event have raised questions about the stability of inshore bottlenose dolphin (Tursiops truncatus) populations throughout the region. Several factors could have contributed to the ongoing event, but little attention has been paid to the potential effects of increased search effort and reporting of strandings associated with oil spill response activities, which were widespread for an extended period. This study quantified the influence of increased search effort by estimating the number of bottlenose dolphin strandings reported by oil spill responders and comparing monthly stranding rates with and without response-related records. Results showed that response teams reported an estimated 58% of strandings during the Active Response period within the study area. Comparison of Poisson rates tests showed that when responder-influenced stranding records were removed, the monthly stranding rates from the Active Response period (May 2010 –April 2014) were similar to the Post-Removal Actions Deemed Complete period (May 2013 –March 2015) (e.g., p = 0.83 for remote areas in Louisiana). Further, analyses using the Getis-Ord Gi* spatial statistic showed that when response-related stranding reports were removed from the Active Response period, significant spatial clustering of strandings (p < 0.05) was reduced by 48% in coastal Louisiana. Collectively, these results suggest that increased search effort resulting from the Deepwater Horizon oil spill response throughout remote portions of the Unusual Mortality Event geographic region had the capacity to increase reporting and recovery of marine mammal strandings to unusually high levels. To better understand how stranding data relates to actual mortality, more work is needed to quantify dolphin population size, population trends, and carcass detection rates including the role of search effort. This is vital for understanding the status of a protected species within the northern Gulf of Mexico.

Two New Species of Saccocoelioides (Digenea: Haploporidae) with Phylogenetic Analysis of the Family, Including Species of Saccocoelioides from North, Middle, and South America

Two cryptic species of haploporid digeneans belonging in Saccocoelioides are described from Costa Rica: one from a poeciliid fish, Poecilia gillii, and the other from a characid fish, Astyanax aeneus. Traditional morphological features are examined and found to be largely inefficient for differentiating among the new species and 20 New World congeners. Comparison of ribosomal DNA sequences among the 2 new species, 2 North American, 4 Middle American, and 3 South American species of Saccocoelioides, including the type-species Saccocoelioides nanii from Argentina and Saccocoelioides sogandaresi from Texas, is effective in differentiating among these species. A Bayesian inference analysis is conducted using a concatenated alignment of the same 2 ribosomal gene regions from 35 species belonging in the Haploporoidea and rooted by the atractotrematid Isorchis anomalus. The analysis provides stronger support for a close relationship between species in Saccocoelioides and Intromugil; thus, Intromugil is transferred from the Waretrematinae to the Chalcinotrematinae. Additionally, interrelationships among 11 species of Saccocoelioides are resolved and reveal a distinct genetic rift suggesting the presence of 2 distinct lineages within the genus, 1 containing the type-species and the other containing a group of species that more closely resemble other genera in the subfamily. Taxonomy of Saccocoelioides is discussed, and observations made during the present study justify taking several taxonomic actions: new combinations are proposed for Saccocoelioides tilapiae n. comb., formerly in the now-defunct Culuwiya, and Saccocoelioides ruedasueltensis n. comb., formerly in Chalcinotrema; Saccocoelioides guaporense nomen novem is proposed for Lecithobotrioides elongatus; Saccocoelioides papernai is considered a junior subjective synonym of Saccocoelioides overstreeti; Saccocoelioides godoyi is considered a junior subjective synonym of Saccocoelioides szidati; Saccocoelioides magnorchis and Saccocoelioides saccodontis are considered species inquirendae; and Saccocoelioides adelae is considered a nomen nudum. Four new hosts are reported for Saccocoelioides cichlidorum: Amphilophus lyonsi, Amatitlania nigrofasciatus, Amatitlania septemfasciatus, and Hypsophrys nicaraguensis. Molecular data call into question some existing species identifications in Saccocoelioides and reveal that molecular tools combined with traditional taxonomy are required for accurately identifying species in the genus. Twenty-two species of Saccocoelioides are formally accepted, but it is noted that as new molecular data become available, some of these species may be transferred to other genera in the subfamily.

A new species of leech of the genus Placobdella (Hirudinida, Glossiphoniidae) from the American alligator (Alligator mississippiensis) in Mississippi, USA

To date, the only species of leech reported from the American Alligator, Alligatormississippiensis is Placobdellamultilineata. Seven specimens of a previously undescribed species of Placobdella were collected from the feet and lower jaw of a single female alligator from the Pascagoula River Wildlife Management Area, George County, Mississippi. The new species was named Placobdellasiddalli Richardson & Moser, sp. n., in honor of the contributions of Dr. Mark Siddall to our understanding of the biology of leeches. Placobdellasiddalli Richardson & Moser is similar to other papillated members of the genus Placobdella, but differs from Placobdellaali Hughes & Siddall, 2007, Placobdellarugosa (Verrill, 1874), Placobdellamultilineata Moore, 1953, and Placobdellapapillifera (Verrill, 1872) in coloration, papillation, ventral striping, and in the possession of a relatively large caudal sucker. In addition, molecular comparison of 626 nucleotides of CO-I between the new species and other papillated leeches (P.ali, P.multilineata, Placobdellaornata, P.papillifera, P.rugosa) revealed interspecific differences of 14.0–18.0% (88–113 nucleotides).

Description of three species of Isorchis (Digenea: Atractotrematidae) from Australia

Three species of Isorchis Durio and Manter, 1969 are described from Australian waters. Isorchis megas sp. nov. is described from the spotbanded scat, Selenotoca multifasciata (Richardson), off Western Australia (WA) and Northern Territory (NT); Isorchis currani sp. nov. is described from S. multifasciata off NT; and Isorchis anomalus sp. nov. is described from the milkfish, Chanos chanos Forsskål, off WA. Isorchis megas sp. nov. can be differentiated from the other species of Isorchis by possessing a single, large egg that is greater than 20% of the body length; having a shorter body (the largest specimen is less than 500 μm); and utilizing a scatophagid rather than a chanid host. Isorchis currani sp. nov. can be differentiated from species of Isorchis other than I. megas sp. nov. by utilizing a scatophagid rather than a chanid host; it is differentiated from I. megas sp. nov. in having eggs that are 11-15% of the body length. Isorchis anomalus sp. nov. can be differentiated from all other species of Isorchis in possessing an irregular shaped genital pore rather than one that is circular to oblong. A Bayesian inference analysis of partial 28S rDNA sequences of the three new species of Isorchis and 30 other haploporoids revealed 1) the monophyly of the Atractotrematidae Yamaguti, 1939, 2) the two species of Isorchis infecting S. multifasciata were each other's closest relative, and 3) that Isorchis was most closely related to Pseudomegasolena Machida and Komiya, 1976 rather than Atractotrema Goto and Ozaki, 1929 although sequence data are not yet available for a member of Pseudisorchis Ahmad, 1985.

Redescription and phylogenetic relationships of the rare Lyperosomum sarothrurae Baer, 1959 (Digenea: Dicrocoeliidae)

Lyperosomum sarothrurae Baer, 1959 is a rare dicrocoeliid described based on a single specimen from Belgian Congo, now Democratic Republic of the Congo, and never reported again. The original description lacked several important details of the species morphology. This work provides morphological redescription of Lyp. sarothrurae based on specimens from Kibale National Park, Uganda which is about 200 kilometres from the type locality. Results of re-examination of the holotype are also provided. Morphology of Lyp. sarothrurae shows some characteristics intermediate between those of the species rich genus Lyperosomum Looss, 1899 and Megacetabulum Oshmarin, 1964 that includes only 3 species. Due to the lack of clear morphological differences between the two genera, Megacetabulum is considered here as a junior synonym of Lyperosomum. Molecular phylogenetic analysis including Lyp. sarothrurae and all currently available partial sequences of the nuclear ribosomal 28S RNA gene of dicrocoeliid species is also included and its results are discussed.

New genus of opecoelid trematode from Pristipomoides aquilonaris (Perciformes: Lutjanidae) and its phylogenetic affinity within the family Opecoelidae

Bentholebouria colubrosa gen. n. et sp. n. (Digenea: Opecoelidae) is described in the wenchman, Pristipomoides aquilonaris (Goode et Bean), from the eastern Gulf of Mexico, and new combinations are proposed: Bentholebouria blatta (Bray et Justine, 2009) comb. n., Bentholebouria longisaccula (Yamaguti, 1970) comb. n., Bentholebouria rooseveltiae (Yamaguti, 1970) comb. n., and Bentholebouria ulaula (Yamaguti, 1970) comb. n. The new genus is morphologically similar to Neolebouria Gibson, 1976, but with a longer cirrus sac, entire testes, a rounded posterior margin with a cleft, and an apparent restriction to the deepwater snappers. Morphologically, the new species is closest to B. blatta from Pristipomoides argyrogrammicus (Valenciennes) off New Caledonia but can be differentiated by the nature of the internal seminal vesicle (2-6 turns or loops rather than constrictions), a longer internal seminal vesicle (occupying about 65% rather than 50% of the cirrus sac), a cirrus sac that extends further into the hindbody (averaging 136% rather than 103% of the distance from the posterior margin of the ventral sucker to the ovary), and a narrower body (27% rather than 35% mean width as % of body length). A Bayesian inference analysis of partial sequence of the 28S rDNA from Neolebouria lanceolata (Price, 1934), Cainocreadium lintoni (Siddiqi et Cable, 1960), Hamacreadium mutabile Linton, 1910, Opecoeloides fimbriatus (Linton, 1910), Podocotyloides brevis Andres et Overstreet, 2013, the new species, and previously published comparable sequences from 10 opecoelid species revealed two clades. One clade includes deep-sea (> or = 200 m) and freshwater fish opecoelids + Opecoeloides Bremser in Rudolphi, 1819, and a second clade included those opecoelids from shallow-water marine, perciform fishes.

Change in rank of Megaperidae (Trematoda) to Megaperinae within the Apocreadiidae and description of Haintestinum amplum n. g., n. sp

Haintestinum amplum n. g., n. sp. is described from the scrawled cowfish, Acanthostracion quadricornis, collected in the Eastern Gulf of Mexico off Florida, USA. The new species is relatively large and shares characters of the Apocreadiidae and Megaperidae but conforms to the diagnosis of neither. It belongs in a new genus possessing a pharynx with lobed anterior margin and intestine terminating in paired ani, like in megaperids, and, when compared with apocreadiids, it shares important anatomical features, including an I-shaped excretory vesicle, canicular seminal vesicle, eye-spot remnants, and pretesticular uterus and lacks a cirrus and cirrus sac. The H-shaped intestine and large funnel-shaped oral sucker without a U-shaped sphincter encircling half the anterior aperture are the most notable diagnostic characters of the new monotypic genus. Additionally, the phylogenetic position of the Megaperidae is investigated for the first time, using analysis of partial 28S rDNA gene sequences from H. amplum, two species in the Megapera, Thysanopharynx elongatus, and previously published 28S sequences of species from members of the Apocreadiata, Haploporoidae, Lepocreadiata, and Opisthorchiata. The resulting analysis demonstrated a close relationship among the new genus and the three species of megaperids, and the megaperids were most closely allied with Schistorchis zancli of the apocreadiids. Moreover, we now consider Megaperidae as the subfamily Megaperinae within the Apocreadiidae.

A new species of Intromugil (Digenea: Haploporidae) and redescription of Intromugil mugilicolus

Intromugil alachuaensis n. sp. is described based on specimens collected from the flathead grey mullet ( Mugil cephalus ) from the Santa Fe River in Florida. The new species is the fourth recognized species in the genus and the second from North America, with the other 2 being confined to South America. Intromugil mugilicolus from Louisiana and Mississippi is redescribed based on the holotype and newly collected material that was not flattened prior to fixation. Two generic features not previously reported are apparent in the new material from I. mugilicolus and I. alachuaensis n. sp.: an armed oral sucker and a series of sacs containing glandular material arranged in symmetrical rows in the hermaphroditic duct. Intromugil alachuaensis differs from I. mugilicolus by having an oral sucker longer than wide, body spines smaller and lanceolate rather than longer and hastate, and smaller vitelline follicles. Intromugil alachuaensis n. sp. differs from Intromugil simonei by having a large elongated pharynx rather than a smaller subspherical one, a proportionately larger and longer oral sucker, and a longer prepharynx (greater than 1 pharyngeal length). Intromugil alachuaensis n. sp. differs from Intromugil annakohnae by having a longer than wide pharynx, a relatively large oral sucker, less extensive vitellarium, and smaller body spines. Comparison of more than 2,400 base-pair-long sequences of nuclear rDNA (partial 18S, complete ITS1, complete 5.8S, complete ITS2, and partial 28S) from I. mugilicolus and I. alachuaensis n. sp. reveals 110 pairwise differences, including gaps, thus supporting our proposal of a new species. These represent the first published sequences from species in this genus.

Review of haploporid (Trematoda) genera with ornate muscularisation in the region of the oral sucker, including four new species and a new genus

Species of the Haploporidae Nicoll, 1914 with elaborate muscularisation of the oral sucker belong in three trematode genera, including three new species and a new genus from the intestine of fishes in Australian waters. Spiritestis Nagaty, 1948 is resurrected and S. herveyensis n. sp. is described from the mullet Moolgarda seheli (Forsskål) collected in Hervey Bay, Queensland, Australia; the latter differs from S. arabii Nagaty, 1948 in that the position of the genital pore is pharyngeal rather than post-pharyngeal and the geographical range is off Australia rather than the Red Sea. A new genus is proposed for two new species, with a uniquely ornamented oral sucker, which infect Australian scatophagids. Members of Capitimitta n. g. are distinguished from Waretrema Srivastava, 1937, species of which have a simple oral sucker with six radially arranged anterior muscular lobes, in that their oral sucker is V-shaped with six embedded muscular finger-like structures in the anteroventral portion. The relatively small C. darwinensis n. sp., collected from Selenotoca multifasciata (Richardson) at Darwin, Northern Territory, Australia, is distinguished from C. costata n. sp., collected from Scatophagus argus (Linnaeus) in the same locality and S. multifasciata off Brisbane, Australia, and by having smaller eggs, a vitellarium commencing at a level close to the ventral sucker rather than at greater than one ovarian length posterior to the ventral sucker, and shorter tegumental body spines. Sequence data of a c.2,500 bp region of the 3' end of 18S, the entire ITS region and the 5' end of the 28S revealed that Spiritestis and Capitimitta are not as closely related as some morphological features would suggest and are probably not the closest relative of each other. What has been reported as Waretrema piscicolum Srivastava, 1937 probably consists of several species, some in different genera, and one, based on material collected by Dr Masaaki Machida, is proposed as Spiritestis machidai n. sp. from Crenimugil crenilabis (Forsskål) off Japan. Phylogenetic hypotheses, based on analysis of an alignment of partial 28S sequences with other haploporids, provide a framework for the evaluation of interrelationships within the Haploporidae. These analyses show that: (1) Spiritestis and Capitimitta are supported within the Haploporidae; (2) branches to Forticulcita Overstreet, 1982, Saccocoelioides Szidat, 1954, Spiritestis and Capitimitta create a clade that is sister to haploporines from the Mediterranean Sea; (3) the branch to Saccocoelioides, Spiritestis and Capitimitta create a polytomy; and (4) the two new species of Capitimitta, plus an immature specimen of an unnamed species, form a monophyletic clade.

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

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