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1. Infection of Diplostomum spp. in invasive round gobies in the St Lawrence River, Canada

   https://doi.org/10.1017/S0022149X21000559  

   Marcogliese, D.J. ; Locke, S.A. ( January 2021 , Journal of Helminthology)

   Abstract The round goby ( Neogobius melanostomus ) is a successful invader of the Great Lakes–St Lawrence River basin that harbours a number of local parasites. The most common are metacercariae of the genus Diplostomum . Species of Diplostomum are morphologically difficult to distinguish but can be separated using molecular techniques. While a few species have been sequenced from invasive round gobies in this study system, their relative abundance has not been documented. The purpose of this study was to determine the species composition of Diplostomum spp. and their relative abundance in round gobies in the St Lawrence River by sequencing the barcode region of cytochrome c oxidase I. In 2007–2011, Diplostomum huronense (= Diplostomum sp. 1) was the most common, followed in order by Diplostomum indistinctum (= Diplostomum sp. 4) and Diplostomum indistinctum sensu Galazzo, Dayanandan, Marcogliese & McLaughlin (2002). In 2012, the most common species infecting the round goby in the St Lawrence River was D. huronense , followed by D. indistinctum and Diplostomum gavium (= Diplostomum sp. 3). The invasion of the round goby in the St Lawrence River was followed by a decline of Diplostomum spp. in native fishes to low levels, leading to the previously published hypothesis that the presence of the round goby has led to a dilution effect. Herein, it is suggested that despite the low infection levels in the round goby, infections still may lead to spillback, helping to maintain Diplostomum spp. in native fishes, albeit at low levels. 

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2. Fish assemblage response to removal of a low‐head dam in the lower reach of a tropical island river

   https://doi.org/10.1111/fwb.13893  

   Cancel Villamil, Johann J. ; Locke, Sean A. ( March 2022 , Freshwater Biology)

   Dams are often removed from rivers to restore habitat connectivity for biota such as fish. Removal of inland dams is well studied in temperate mainland rivers but this approach has been little studied in fish assemblages in islands, tropic systems, or for dams near the mouth of the river. In Puerto Rico, one of the most intensively dammed territories in the world, all native river fishes migrate between fresh water and the sea, and previous work shows that these movements are impeded or blocked by dams.

   Fish assemblages were compared before and after removal of the Cambalache dam, a porous, low‐head structure near the mouth of the Río Grande de Arecibo, as well as in two other rivers in western Puerto Rico, one with a similarly sized and positioned dam, and one reference river without artificial barriers. Fish were sampled using backpack electrofishing on 39 occasions during 2017–2019, including seven samples collected after removal of the Cambalache dam, at four to six sites per river.

   Fish assemblages upstream from dams were poorer in species, and species richness showed a marginal tendency (p = 0.0515) to increase upstream of the Cambalache dam 3 months after its removal. The two small lowland dams studied herein limited the upstream extent of marine species, which recolonised upstream sites of the Río Grande de Arecibo after removal of the Cambalache dam. An estimate of relative density (catch per unit effort) of common native freshwater species was higher above these two dams, and decreased at upstream sites after removal of the Cambalache dam. The estimated relative density of a native freshwater species that is of conservation concern, the American eel (Anguilla rostrata), was reduced above dams, and increased upstream of the former Cambalache dam after its removal.

   In extensive surveys conducted previously in Puerto Rico, sampling was concentrated higher in the catchment, and native fishes were more common and abundant below than above dams. The present work was conducted near the river mouth, and opposite results were observed. These contrasting results suggest that the effects of dams (or dam removal) on fish assemblages vary along the river gradient, although data from other systems are needed to confirm this.

   The present results suggest low‐head dam removal to be a viable method of restoring connectivity in fish assemblages in lower reaches of rivers in Puerto Rico and, potentially, other tropical islands. Removal of dams near the mouth of the river appears to be of particular benefit to marine fish species that use lower river reaches.

    

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3. Re-examination of the Southern Hemisphere truffle genus Amylascus (Pezizaceae, Ascomycota) and characterization of the sister genus Nothoamylascus gen. nov.

   https://doi.org/10.3767/persoonia.2023.51.03  

   Healy, R.A. ; Truong, C. ; Castellano, M.A. ; Bonito, G. ; Trappe, J. ; Caiafa, M.V. ; Mujic, A.B. ; Nouhra, E. ; Sánchez-Ramírez, S. ; Smith, M.E. ( January 2023 , Persoonia - Molecular Phylogeny and Evolution of Fungi)

   Amylascusis a genus of ectomycorrhizal truffles withinPezizaceaethat is known from Australia and contains only two described species,A. herbertianusandA. tasmanicus. Species ofAmylascusare closely related to truffles (Pachyphlodes,Luteoamylascus) and cup fungi (Plicariella) from the Northern Hemisphere. Here we reevaluate the species diversity ofAmylascusand related taxa from southern South America and Australia based on new morphological and molecular data. We identify previously undocumented diversity and morphological variability in ascospore color, ascospore ornamentation, hymenial construction, epithecium structure and the amyloid reaction of the ascus in Melzer’s reagent. We redescribe twoAmylascusspecies from Australia and describe seven newAmylascusspecies, five from South America and two from Australia. This is the first report ofAmylascusspecies from South America. We also describe the new South American genusNothoamylascusas sister lineage to thePachyphlodes-Amylascus-Luteoamylascusclade (includingAmylascus,Luteoamylascus,Pachyphlodes, andPlicariella). We obtained ITS sequences of mitotic spore mats fromNothoamylascus erubescensgen. & sp. nov. and four of the seven newly describedAmylascusspecies, providing the first evidence of mitotic spore mats inAmylascus. Additional ITS sequences from mitotic spore mats reveal the presence of nine additional undescribedAmylascusand oneNothoamylascusspecies that do not correspond to any sampled ascomata. We also identify three additional undescribedAmylascusspecies based on environmental sequences from the feces of two ground-dwelling bird species from Chile,Scelorchilus rubeculaandPteroptochos tarnii. Our results indicate that ascomata fromAmylascusandNothoamylascusspecies are rarely collected, but molecular data from ectomycorrhizal roots and mitotic spore mats indicate that these species are probably common and widespread in southern South America. Finally, we present a time-calibrated phylogeny that is consistent with a late Gondwanan distribution. The time since the most recent common ancestor of: 1) the familyPezizaceaehad a mean of 276 Ma (217–337 HPD); 2) theAmylascus-Pachyphlodes-Nothoamylascus-Luteoamylascusclade had a mean of 79 Ma (60–100 HPD); and 3) theAmylascus-Pachyphlodesclade had a mean of 50 Ma (38–62 HPD). The crown age ofPachyphlodeshad a mean of 39 Ma (25–42 HPD) andAmylascushad a mean age of 28 Ma (20–37 HPD), falling near the Eocene-Oligocene boundary and the onset of the Antarctic glaciation (c. 35 Ma).

    

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4. Morphology, Ultrastructure, and Molecular Phylogeny of Rozella multimorpha , a New Species in Cryptomycota

   https://doi.org/10.1111/jeu.12452  

   Letcher, Peter M. ; Longcore, Joyce E. ; James, Timothy Y. ; Leite, Domingos S. ; Simmons, David Rabern ; Powell, Martha J. ( August 2017 , Journal of Eukaryotic Microbiology)

   Increasing numbers of sequences of basal fungi from environmentalDNAstudies are being deposited in public databases. Many of these sequences remain unclassified below the phylum level because sequence information from identified species is sparse. Lack of basic biological knowledge due to a dearth of identified species is extreme in Cryptomycota, a new phylum widespread in the environment and phylogenetically basal within the fungal lineage. Consequently, we are attempting to fill gaps in the knowledge ofRozella, the best‐known genus in this lineage.Rozellais a genus of unwalled, holocarpic, endobiotic parasites of hosts including Chytridiomycota, Blastocladiomycota, Oomycota, Basidiomycota, and a green alga, with most species descriptions based on morphology and host specificity. We found aRozellaparasitizing aPythiumhost that was a saprobe on spruce pollen bait placed with an aquatic sample. We characterized the parasite with light microscopy,TEMof its zoospores and sporangia, and its 18S/28SrDNA. Comparison with otherRozellaspecies indicates that the new isolate differs morphologically, ultrastructurally, and genetically fromRozellaspecies for which we have data. Features of the zoospore also differ from those of previously studied species. Herein we describe theRozellaas a new species,R. multimorpha.

    

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5. Parasite spillover to native hosts from more tolerant, supershedding invasive hosts: Implications for management

   https://doi.org/10.1111/1365-2664.13906  

   Ortega, Nicole ; Roznik, Elizabeth A. ; Surbaugh, Kerri L. ; Cano, Natalia ; Price, Wayne ; Campbell, Todd ; Rohr, Jason R. ( November 2021 , Journal of Applied Ecology)

   Introduced hosts are capable of introducing parasite species and altering the abundance of parasites that are already present in native hosts, but few studies have compared the tolerances of native and invasive hosts to introduced parasites or identified the traits of introduced hosts that make them supershedders of non‐native parasites.

   Here, we compare the effects of a nematodeAplectana hamatospiculathat is native to Cuba but appears to be introduced to Florida on the native Floridian treefrog,Hyla femoralis, and on the Cuban treefrog (CTF),Osteopilus septentrionalis. We were particularly interested in CTFs because their introduction to Florida has led to reported declines of native treefrogs.

   In the laboratory, infection withA. hamatospiculacaused a greater loss in body mass ofH. femoralisthan CTFs despiteH. femoralisshedding fewer total worms in their faeces than CTFs. Field collections of CTFs,H. femoralis, and another native Floridian treefrog,H.squirella(Squirrel treefrog) from Tampa, FL also showed that CTFs shed more larval worms in their faeces than both native frogs when controlling for body size. Hence, the non‐native CTF is a supershedder of this non‐native parasite that is spilling over to less tolerant native treefrogs.

   Any conservation intervention to reduce the effects of CTFs on native treefrogs would benefit from knowing the traits that contribute to the invasive host being a supershedder of this parasite. Hence, we conducted necropsies on 330 CTFs to determine how host sex and body size affect the abundance ofA. hamatospicula, and two other common parasites in this species (acuariid nematodes and trematode metacercariae).

   There was a significant linear increase inA. hamatospiculaand encysted acuariids with CTF body size, but there was no detectable relationship between host body size and the intensity of metacercariae. Female CTFs were bigger, lived longer and, on average, had moreA. hamatospiculathan male CTFs.

   Synthesis and applications. These results of the study suggest that there is parasite spillover from the invasive Cuban treefrog (CTF) to native treefrogs in Florida. Additionally, at least some of the adverse effects of CTFs on native treefrogs could be caused by the introduction and amplification of this introduced parasite, and female and larger CTFs seem to be amplifying these infections more than males and smaller CTFs, respectively, suggesting that management could benefit from targeting these individuals.

    

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