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Challenges in the recognition of trematode species: Consideration of hypotheses in an inexact science

Part of: Trematodes 2024 Conference

Published online by Cambridge University Press:  22 April 2025

T.H. Cribb Open the ORCID record for T.H. Cribb [Opens in a new window] ,
D.P. Barton Open the ORCID record for D.P. Barton [Opens in a new window] ,
D. Blair Open the ORCID record for D. Blair [Opens in a new window] ,
N.J. Bott Open the ORCID record for N.J. Bott [Opens in a new window] ,
R.A. Bray Open the ORCID record for R.A. Bray [Opens in a new window] ,
R.D. Corner Open the ORCID record for R.D. Corner [Opens in a new window] ,
S.C. Cutmore Open the ORCID record for S.C. Cutmore [Opens in a new window] ,
M.L.I. De Silva Open the ORCID record for M.L.I. De Silva [Opens in a new window] ,
B. Duong Open the ORCID record for B. Duong [Opens in a new window]  and
A. Faltýnková Open the ORCID record for A. Faltýnková [Opens in a new window]
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T.H. Cribb*
Affiliation:
Queensland Museum, Biodiversity and Geosciences Program, South Brisbane, Queensland 4101, Australia
D.P. Barton
Affiliation:
School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, New South Wales 2658, Australia
D. Blair
Affiliation:
College of Science and Engineering, James Cook University, Australia
N.J. Bott
Affiliation:
School of Science, RMIT University, PO Box 71, Bundoora VIC 3083
R.A. Bray
Affiliation:
Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
R.D. Corner
Affiliation:
Department of Primary Industries, Ecosciences Precinct, Dutton Park, Queensland 4102, Australia
S.C. Cutmore
Affiliation:
Queensland Museum, Biodiversity and Geosciences Program, South Brisbane, Queensland 4101, Australia
M.L.I. De Silva
Affiliation:
Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, Western Australia
B. Duong
Affiliation:
School of the Environment, The University of Queensland, 4072 Australia
A. Faltýnková
Affiliation:
Department of Forest Ecology, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemedelská 3, Brno, 613 00, Czech Republic
A. Gonchar
Affiliation:
Department of Invertebrate Zoology, St Petersburg University, Universitetskaya emb. 7-9, Saint Petersburg 199034, Russia Laboratory of Parasitic Worms and Protists, Zoological Institute of the Russian Academy of Sciences, Universitetskaya emb. 1, Saint Petersburg 199034, Russia
R.F. Hechinger
Affiliation:
Scripps Insitution of Oceanography, University of California San Diego, La Jolla, California, USA
K.K. Herrmann
Affiliation:
Tarleton State University, Stephenville, Texas, USA
D.C. Huston
Affiliation:
Australian National Insect Collection, National Research Collections Australia, CSIRO, PO Box 1700, Canberra, ACT 2601, Australia
P.T.J. Johnson
Affiliation:
Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA
G. Kremnev
Affiliation:
Laboratory of Parasitic Worms and Protists, Zoological Institute of the Russian Academy of Sciences, Universitetskaya emb. 1, Saint Petersburg 199034, Russia
R. Kuchta
Affiliation:
Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Branišovská 31, 370 05 Ceské Budejovice, Czech Republic
C. Louvard
Affiliation:
Water Research Group, Unit for Environmental Science and Management, North-West University - Potchefstroom campus, 11 Hoffman St, Potchefstroom 2531, North West, South Africa
W.J. Luus-Powell
Affiliation:
DSI-NRF SARChI Chair (Ecosystem Health), Department of Biodiversity, University of Limpopo, 0727, South Africa
S.B. Martin
Affiliation:
Centre for Sustainable Aquatic Ecosystems, Harry Butler Institute, Murdoch University, 90 South Street, Murdoch, 6150, Western Australia, Australia
T.L. Miller
Affiliation:
Queensland Museum, Biodiversity and Geosciences Program, South Brisbane, Queensland 4101, Australia
G. Pérez-Ponce de León
Affiliation:
Escuela Nacional de Estudios Superiores Unidad Mérida, Universidad Nacional Autónoma de México, Mérida, Yucatán, C.P. 97357, Mexico
N.J. Smit
Affiliation:
Water Research Group, Unit for Environmental Science and Management, North-West University - Potchefstroom campus, 11 Hoffman St, Potchefstroom 2531, North West, South Africa
V.V. Tkach
Affiliation:
Department of Biology, University of North Dakota, Grand Forks, North Dakota, USA
M. Truter
Affiliation:
Water Research Group, Unit for Environmental Science and Management, North-West University - Potchefstroom campus, 11 Hoffman St, Potchefstroom 2531, North West, South Africa
T. Waki
Affiliation:
Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan
A. Vermaak
Affiliation:
Water Research Group, Unit for Environmental Science and Management, North-West University - Potchefstroom campus, 11 Hoffman St, Potchefstroom 2531, North West, South Africa
N.Q-X. Wee
Affiliation:
Queensland Museum, Biodiversity and Geosciences Program, South Brisbane, Queensland 4101, Australia
R.Q-Y. Yong
Affiliation:
Water Research Group, Unit for Environmental Science and Management, North-West University - Potchefstroom campus, 11 Hoffman St, Potchefstroom 2531, North West, South Africa
T.J Achatz
Affiliation:
Department of Natural Sciences, Middle Georgia State University, Macon, Georgia, USA
*
Corresponding author: T.H. Cribb; Email: thomas.cribb@qm.qld.gov.au
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Abstract

The description and delineation of trematode species is a major ongoing task. Across the field there has been, and currently still is, great variation in the standard of this work and in the sophistication of the proposal of taxonomic hypotheses. Although most species are relatively unambiguously distinct from their congeners, many are either morphologically very similar, including the major and rapidly growing component of cryptic species, or are highly variable morphologically despite little to no molecular variation for standard DNA markers. Here we review challenges in species delineation in the context provided to us by the historical literature, and the use of morphological, geographical, host, and molecular data. We observe that there are potential challenges associated with all these information sources. As a result, we encourage careful proposal of taxonomic hypotheses with consideration for underlying species concepts and frank acknowledgement of weaknesses or conflict in the data. It seems clear that there is no single source of data that provides a wholly reliable answer to our taxonomic challenges but that nuanced consideration of information from multiple sources (the ‘integrated approach’) provides the best possibility of developing hypotheses that will stand the test of time.

Keywords

taxonomyhypothesessynonymyspecies conceptcryptic species

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Review Article
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Journal of Helminthology , Volume 99 , 2025 , e54
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© The Author(s), 2025. Published by Cambridge University Press

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