Diversity, specificity and speciation in larval Diplostomidae (Platyhelminthes: Digenea) in the eyes of freshwater fish, as revealed by DNA barcodes.
Larvae (metacercariae) in some species of Diplostomidae (Platyhelminthes: Digenea) inhabit fish eyes and are difficult to identify to species based on morphology. DNA barcoding has clarified the diversity and life cycles of diplostomids in North America, Europe and Africa, but has seldom been used in parasites sampled in large numbers or at large spatial scales. Here, distance-based analysis of cytochrome c oxidase 1 barcodes and, in some specimens, internal transcribed spacer (ITS-1, 5.8S, ITS-2) sequences was performed for over 2000 diplostomids from Africa, the Middle East, Europe, Asia and the Americas. Fifty-two species of Diplostomum, Tylodelphys and Austrodiplostomum (Digenea: Diplostomidae) were distinguished. The 52 species comprise 12 identified species, six species in two species complexes and 34 putative species, and 33/52 had been delineated in previous studies. Most (23/40) of the unidentified, putative species distinguished by cytochrome c oxidase 1 distances were supported by at least one additional line of evidence. As the intensity of sampling of the 52 species increased, variation in cytochrome c oxidase 1 decreased between and increased within species, while the spatial scale at which species were sampled had no effect. Nonetheless, variation between species always exceeded variation within species. New life-cycle linkages, geographic and host records, and genetic data were recorded in several species, including Tylodelphys jenynsiae, Tylodelphys immer and Diplostomum ardeae. Species of Diplostomum inhabiting the lens are less host-specific and less numerous than those infecting other tissues, suggesting that reduced immune activity in the lens has influenced rates of speciation.
Department of Biology, University of Puerto Rico at Mayagüez, Box 9000, Mayagüez, 00681-9000, Puerto Rico; Aquatic Biodiversity Section, Watershed Hydrology and Ecology Research Division, Water Science and Technology Directorate, Science and Technology Branch, St. Lawrence Centre, Environment Canada, 105 McGill, 7th floor, Montreal, Quebec H2Y 2E7, Canada. Electronic address: sean.locke@upr.edu.
Sean A
SA
Locke
Department of Biology, College of Science, University of Tikreet, Tikreet, Iraq.
Fatima S
FS
Al-Nasiri
Department of Veterinary Medical Sciences, Alma Mater Studiorum Università di Bologna, Via Tolara di Sopra 50, 40064 Ozzano Emilia (BO), Italy.
Monica
M
Caffara
Museo de La Plata, División Zoología Invertebrados, Paseo del Bosque S/N° (1900), La Plata, Buenos Aires, Argentina.
Fabiana
F
Drago
Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, August-Thienemann-Strasse 2, 24302 Plön, Germany.
Martin
M
Kalbe
Biology Department, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada.
Angela Rose
AR
Lapierre
Biology Department, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec H4B 1R6, Canada.
J Daniel
JD
McLaughlin
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei Province 430072, People's Republic of China.
Pin
P
Nie
University of Southern Mississippi, Gulf Coast Research Laboratory, 703 East Beach Drive, Ocean Springs, MS 39564, USA.
Robin M
RM
Overstreet
Post-Doctor National Program Scholarship/CAPES, Post-Graduate Program in Health and Environment, Tiradentes University, Murilo Dantas Avenue, 300, Farolândia, Aracaju, Sergipe 49032-490, Brazil; State University of Maringá, Center of Biological Sciences, Nupelia - Icthyoparasitology Laboratory, Av Colombo, No. 5790, Block G90, room 11, villa 7, 87020-900 Maringá, PR, Brazil.
Geza T R
GT
Souza
State University of Maringá, Center of Biological Sciences, Nupelia - Icthyoparasitology Laboratory, Av Colombo, No. 5790, Block G90, room 11, villa 7, 87020-900 Maringá, PR, Brazil.
Ricardo M
RM
Takemoto
Aquatic Biodiversity Section, Watershed Hydrology and Ecology Research Division, Water Science and Technology Directorate, Science and Technology Branch, St. Lawrence Centre, Environment Canada, 105 McGill, 7th floor, Montreal, Quebec H2Y 2E7, Canada.
David J
DJ
Marcogliese
D000818:Animals; D016000:Cluster Analysis; D058893:DNA Barcoding, Taxonomic / Q000379:methods*; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics; D005128:Eye Diseases / Q000469:parasitology / Q000662:veterinary*; D005393:Fish Diseases / Q000469:parasitology*; D005618:Fresh Water / Q000469:parasitology; D014644:Genetic Variation; D007814:Larva; D008018:Life Cycle Stages / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D014200:Trematoda / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification
D021903:DNA, Ribosomal Spacer; D003576:Electron Transport Complex IV
DNA barcode; Ecological speciation; Host specificity; Internal transcribed spacer; Sampling effort; Species delimitation