Proterometra epholkos sp. n. (Digenea: Azygiidae) from Terrapin Creek, Alabama, USA: Molecular characterization of life cycle, redescription of Proterometra albacauda, and updated lists of host and geographic locality records for Proterometra spp. in North America

Description, life cycle, and phylogenetics of Proterometra wigglewomble n. sp. (Digenea: Azygiidae) from the Cahaba River, Alabama, U.S.A

We herein describe Proterometra wigglewomble n. sp. (Digenea: Azygiidae: Azygiinae) from the Cahaba River, Alabama, USA, which asexually reproduces in the compact elimia, Elimia showalteri (Lea, 1860) (Cerithioidea: Pleuroceridae) and matures in the oesophagus of the blackbanded darter, Percina nigrofasciata (Agassiz, 1854) (Perciformes: Percidae). Adults of the new species differ from congeners by having a small body and eggs having a wholly fimbriated surface that appears as a cilia-like brush border. Live naturally-shed cercariae of the new species differ from those of its congeners by having a strongly claviform tail stem bearing aspinose mammillae, a single furca, excretory pores that open on the posterior margin of the single furca, and few eggs in the cercarial distome. The behaviour of the cercaria further differentiates the new species. Naturally-shed cercariae of P. wigglewomble secrete a jelly-like adhesive that coats the surface of the furca and evidently facilitates attachment to the surface of glass, plastic, and snail shell. Attached cercariae vigorously wiggle and thrash about once attached, as if mimicking the larva of a stream insect so as to lure the blackbanded darter to eat it. Phylogenetic analyses recovered monophyletic Azygiidae, comprising monophyletic Leuceruthrinae Goldberger, 1911 and polyphyletic Azygiinae Lühe, 1909. The present study is the largest taxon sampling for Azygiidae and the first to include 28S sequences of Leuceruthrus. Compact elimia and blackbanded darter are new host records for Proterometra. The new species is the 3rd congener reported from the Cahaba River, a region renowned for its fish and snail endemic biodiversity.

AZYGIID PARASITES OF NORTH AMERICAN ENDEMIC PLEUROCERIDS AND CENTRARCHIDS: REVISION OF LEUCERUTHRUS MARSHALL AND GILBERT, 1905 (DIGENEA: AZYGIIDAE), DESCRIPTION OF TWO NEW SPECIES, AND PHYLOGENETIC ANALYSIS

We revise monotypic LeuceruthrusMarshall and Gilbert, 1905 (Azygiidae Lühe, 1909) by emending its generic diagnosis, redescribing its type species (Leuceruthrus micropteriMarshall and Gilbert, 1905), reassigning 2 species (Leuceruthrus stephanocauda [Faust, 1921] n. comb., Leuceruthrus ocalana [Smith, 1935] n. comb.), describing 2 new congeners (Leuceruthrus ksepkai n. sp. and Leuceruthrus blaisei n. sp.), and providing a phylogenetic analysis based on the internal transcribed spacer 2 (ITS2). Leuceruthrus is unique by having oblique preovarian testes, a vitellarium that does not extend anteriad into the forebody, and a uterus that is intercecal and between the ovary and ventral sucker. We describe the cercaria of Leuceruthrus cf. stephanocauda from cercariae shed from Elimia cf. carinifera and Elimia cf. modesta from Big Canoe Creek, Alabama. Leuceruthrus ksepkai n. sp. is described from cercariae shed from rasp elimia, Elimia floridensis (Reeve, 1860) from Holmes Creek, Florida, and Elimia sp. 1 from the Chocktawhatchee River, Florida. It differs from its congeners by the combination of having broadly rounded furcae with slight marginal pigmentation in live cercariae, no spines on the tail stem, distinct anterior and posterior ridges that flank the tail stem portion accommodating the withdrawn distome, minute protuberances occupying the lateral margin of the tail stem for its entire length, and protuberances that encircle the anterior third of the posterior tail stem (immediately posterior to the tail stem portion containing the withdrawn distome). Leuceruthrus blaisei n. sp. infects Elimia sp. and is the only known congener having proportionally small furcae (>tail stem maximum width) with a nipple-like distal projection and numerous minute projections on the tail stem surface. Our phylogenetic analysis included all of our new sequences plus all publicly available ITS2 sequences for Leuceruthrus spp. and Proteromera spp., and supported the monophyly of Leuceruthrus. It recovered L. ksepkai and L. cf. ksepkai in a polytomy, and Leuceruthrus blaisei as monophyletic (identical sequences), with L. micropteri and L. cf. stephanocauda recovered as sister taxa. The present study comprises the first systematic treatment of Leuceruthrus in over a century, the first description of a new species of Leuceruthrus in 117 yr, and the first taxonomic characterization of a species of Leuceruthrus from the Mobile River Basin. It also increases the number of accepted congeners from 1 to 5 and provides new host records (E. cf. carinifera and E. floridensis) for Leuceruthrus spp.

New species of Proterometra (Digenea: Azygiidae) and its life cycle in the Chickasawhay River, Mississippi, USA, with supplemental observations of Proterometra autraini

We describe Proterometra ariasae n. sp. based upon cercariae shed from a freshwater snail, Pleurocera sp., and adults infecting the buccal cavity of longear sunfish, Lepomis megalotis, captured from the Chickasawhay River, Mississippi, USA. We also provide supplemental observations of cercarial and adult paratypes of Proterometra autraini from the Au Train River, Michigan, USA. Sequence data for the ribosomal internal transcribed spacer 2 (ITS2) from adults and cercariae of the new species were identical. Adults of the new species differ from congeners by having (i) a markedly large body, (ii) a proportionally large oral sucker, (iii) ovoid testes, (iv) a strongly muscular and laterally expanded pars prostatica, (v) a uterus that is extensively convoluted between the ovary and ventral sucker (vi) and a vitellarium as long as the caeca and extending posteriad beyond the anterior margin of the testes. Cercariae of the new species differ from those of its congeners by having (i) a tail stem that is shorter than 10mm and that lacks a medial constriction, (ii) obcordate furcae that are wider than long, (iii) mamillae distributed throughout the anterior tail stem only, and (v) a proportionally small distome that has relatively few uterine eggs and remains withdrawn in the anterior tail stem region in actively swimming cercariae. This is the first report of Proterometra from Mississippi, the second description to employ morphology and sequence data to elucidate a life cycle for Proterometra, and the third species of Proterometra from an intermediate host not assigned to Elimia.

First Record of Transversotrema Witenberg, 1944 (Digenea) from the Americas, with Comments on the Taxonomy of Transversotrema patialense (Soparkar, 1924) Crusz and Sathananthan, 1960, and an Updated List of Its Hosts and Geographic Distribution

Specimens of Transversotrema patialense (sensu lato) ( Soparkar, 1924 ) Crusz and Sathananthan, 1960 (Digenea: Transversotrematidae) infected the skin (epidermal spaces beneath scales near pectoral fins) of 4 of 126 (prevalence 3%; mean intensity 1.8) zebrafish ( Danio rerio (Hamilton, 1822) [Cypriniformes: Cyprinidae]) purchased in 2009 and cultured by a California (USA) fish supplier. These fish were sold as "laboratory-reared" and "specific pathogen free," purportedly raised in a recirculating aquaculture system that included zebrafish only. We herein describe the morphological features of this transversotrematid using light and scanning electron microscopy, provide a comprehensive list of hosts (snails and fishes) and geographic locality records for specimens reported as T. patialense, which is perhaps a species complex, and provide a brief historical synopsis of the taxonomic and life history research that has been conducted on this fluke. No species of Transversotrema previously had been reported from the Americas; however, this discovery is not surprising given that: (1) a suitable intermediate host (red-rimmed melania, Melanoides tuberculata (Müller, 1774) [Cerithioidea: Thiaridae]) has been established in California and elsewhere in North America, (2) the zebrafish is a susceptible definitive host, and (3) T. patialense reportedly matures on a broad ecological and phylogenetic spectrum of freshwater fishes. To our knowledge, this is the northern-most geographic locality record for a species of this genus. We suspect this case study represents an example of a parasite that may now be established in North America by the fortuitous co-occurrence of a susceptible, exotic snail host (the red-rimmed melania) and a susceptible, widely distributed, exotic fish host (the zebrafish).