Abstract
Two new species of the genus Dugesia from the Yunnan border region, Southwest China, are described by applying an integrative approach, using morphological, histological, and molecular data. Dugesia repanda Chen & Dong, sp. nov. is characterized by the following features: symmetrical openings of the oviducts into the bursal canal; an upward curving, highly asymmetrical penis papilla; highly elongated and muscularised seminal vesicle of which the major portion is located considerably anterior to the root of the penis papilla; a long connecting duct between the seminal vesicle and diaphragm; a dorsally located penial fold; ejaculatory duct opening subterminally through the dorsal wall of the penis papilla. Dugesia laterocalceata Chen & Dong, sp. nov. is characterized by the following features: hyperplastic ovaries; symmetrical openings of the oviducts; a boot-shaped penis papilla; penis papilla with a dorsal bulge; a connecting duct between the seminal vesicle and diaphragm; ejaculatory duct consistently opening through the right lateral wall of the penis papilla. In the molecular phylogenetic tree, the two new species belong to distinct and independent lineages. Dugesia laterocalceata Chen & Dong, sp. nov. is nested within the Oriental-Australasian clade, whereas D. repanda Chen & Dong, sp. nov. is recovered as a distinct lineage that is sister to the entire Eastern Palearctic-Oriental-Australasian clade.
References
- Benazzi, M., Baguñà, J., Ballester, R. & Del Papa, R. (1975) Further contribution to the taxonomy of the “Dugesia lugubris–polychroa group” with description of Dugesia mediterranea n. sp. (Tricladida, Paludicola). Bollettino di Zoologia, 42, 81–89. https://doi.org/10.1080/11250007509430132
- Carranza, S., Giribet, G., Ribera, C., Baguñà, J. & Riutort, M. (1996) Evidence that two types of 18S rDNA coexist in the genome of Dugesia (Schmidtea) mediterranea (Platyhelminthes, Turbellaria, Tricladida). Molecular Biology and Evolution, 13, 824–832. https://doi.org/10.1093/oxfordjournals.molbev.a025643
- Chen, G.-W., Wang, L., Wu, F., Sun, X.-J., Dong, Z.-M., Sluys, R., Yu, F., Yu-wen, Y.-Q. & Liu, D.-Z. (2022) Two new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from the subtropical monsoon region in Southern China, with a discussion on reproductive modalities. BMC Zoology, 7, 25. https://doi.org/10.1186/s40850-022-00127-8
- Dai, J.-H., Nong, S.-Y., Guo, X.-B., Do, T.-V., Liu, Y., Zhou, R.-C. & Liu, Y. (2022) Three new species of Bredia (Sonerileae, Melastomataceae) from the Sino-Vietnamese border area. PhytoKeys, 195, 107–125. https://doi.org/10.3897/phytokeys.195.83934
- Dessimoz, C. & Gil, M. (2010) Phylogenetic assessment of alignments reveals neglected tree signal in gaps. Genome Biology, 11 (4), R37. https://doi.org/10.1186/gb-2010-11-4-r37
- De Vries, E.J. (1988) A synopsis of the nominal species of the subgenus Dugesia (Platyhelminthes: Tricladida: Paludicola) from Africa and Madagascar. Zoological Journal of the Linnean Society, 92, 345–382. https://doi.org/10.1111/j.1096-3642.1988.tb01729.x
- Harrath, A.H., Sluys, R., Mansour, L., Folefack, G.L., Aldahmash, W., Alwasel, S., Solà, E. & Riutort, M. (2019) Molecular and morphological identification of two new African species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from Cameroon. Journal of Natural History, 53, 253–271. https://doi.org/10.1080/00222933.2019.1577508
- Katoh, K., Rozewicki, J. & Yamada, K.-D. (2019) MAFFT online service: multiple sequence alignment, interactive sequence choice and visualization. Briefings in Bioinformatics, 20 (4), 1160–1166. https://doi.org/10.1093/bib/bbx108
- Kawakatsu, M., Tamura, S., Yamayoshi, T. & Oki, I. (1980) The freshwater planarians from Thailand and South India. Annotationes Zoologicae Japonenses, 53, 254–268.
- Kawakatsu, M., Oki, I., Tamura, S., Yamayoshi, T. & Aditya, A.-K. (1983) A new freshwater planarian from West Bengal. Bulletin of the Biogeographical Society of Japan, 38, 1–10.
- Kawakatsu, M., Oki, I., Tamura, S. & Yamayoshi, T. (1985) Reexamination of freshwater planarians found in tanks of tropical fishes in Japan, with a description of a new species, Dugesia austroasiatica sp. nov. (Turbellaria; Tricladida; Paludicola). Bulletin of the Biogeographical Society of Japan, 40, 1–19.
- Kawakatsu, M., Takai, M., Oki, I., Tamura, S. & Aoyagi, M. (1986) A note on an introduced species of freshwater planarian, Dugesia austroasiatica Kawakatsu, 1985, collected from culture ponds of Tilapia mossambica in Saga City, Kyûshû, Japan (Turbellaria, Tricladida, Paludicola). Bulletin of Fuji Women’s College, 24, Ser. II, 87–94.
- Kawakatsu, M. & Mitchell, R.-W. (1989) Dugesia deharvengi sp. nov., a new troglobitic freshwater planarian from Tham Kubio Cave, Thailand (Turbellaria; Tricladida; Paludicola). Bulletin of the Biogeographical Society of Japan, 44, 175–182.
- Kumar, S., Stecher, G. & Tamura, K. (2016) MEGA7: molecular evolutionary genetics analysis version 7.0 for bigger datasets. Molecular Biology and Evolution, 33 (7), 1870–1874. https://doi.org/10.1093/molbev/msw054
- Lanfear, R., Frandsen, P.-B., Wright, A.-M., Senfeld, T. & Calcott, B. (2017) PartitionFinder 2: New methods for selecting partitioned models of evolution for molecular and morphological phylogenetic analyses. Molecular Biology and Evolution, 34 (3), 772–773. https://doi.org/10.1093/molbev/msw260
- Lázaro, E.-M., Sluys, R., Pala, M., Stocchino, G.-A., Baguñà, J. & Riutort, M. (2009) Molecular barcoding and phylogeography of sexual and asexual freshwater planarians of the genus Dugesia in the Western Mediterranean (Platyhelminthes, Tricladida, Dugesiidae). Molecular Phylogenetics and Evolution, 52 (3), 835–845. https://doi.org/10.1016/j.ympev.2009.04.022
- Marcus, E. (1953) Turbellaria Tricladida. In: Exploration du Parc National de l’Upemba. Mission G.F. de Witte (1946–1949). Fascicule 21. Institut des Parcs Nationaux du Congo Belge, Brussels, pp. 1–62.
- Nguyen, L.-T., Schmidt, H.-A., Haeseler, A. & Minh, B.-Q. (2015) IQ-TREE: A fast and effective stochastic algorithm for estimating maximum-likelihood phylogenies. Molecular Biology and Evolution, 32 (1), 268–274. https://doi.org/10.1093/molbev/msu300
- Pala, M., Casu, S. & Vacca, R.-A. (1981) Dugesia hepta, nuova specie di planaria d’acqua dolce di Sardegna appartenente alla superspecie Dugesia gonocephala (Dugès) (Turbellaria, Tricladida). Bollettino della Società Sarda di Scienze Naturali, 20, 97–107.
- Rambaut, A., Drummond, A.-J., Xie, D., Baele, G. & Suchard, M.-A. (2018) Posterior summarization in Bayesian phylogenetics using Tracer 1.7. Systematic Biology, 67 (5), 901–904. https://doi.org/10.1093/sysbio/syy032
- Ronquist, F., Teslenko, M., Mark, P., Ayres, D.-L., Darling, A., Höhna, S., Larget, B., Liu, L., Suchard, M.-A. & Huelsenbeck, J.-P. (2012) MrBayes 3.2: Efficient Bayesian phylogenetic inference and model choice across a large model space. Systematic Biology, 61 (3), 539–542. https://doi.org/10.1093/sysbio/sys029
- Schmidt, O. (1861) Ueber Planaria torva Autorum. Zeitschrift für wissenschaftliche Zoologie, 11, 89–94.
- Sluys, R., Kawakatsu, M. & Winsor, L. (1998) The genus Dugesia in Australia, with its phylogenetic analysis and historical biogeography (Platyhelminthes, Tricladida, Dugesiidae). Zoologica Scripta, 27 (4), 273–289. https://doi.org/10.1111/j.1463-6409.1998.tb00461.x
- Sluys, R., Solà, E., Gritzalis, K., Vila-Farré, M., Mateos, E. & Riutort, M. (2013) Integrative delineation of species of Mediterranean freshwater planarians (Platyhelminthes: Tricladida: Dugesiidae). Zoological Journal of the Linnean Society, 169, 523–547. https://doi.org/10.1111/zoj.12077
- Solà, E., Leria, L., Stocchino, G.-A., Bagherzadeh, R., Balke, M., Daniels, S.-R., Harrath, A.-H., Khang, T.-F., Krailas, D., Kumar, B., Li, M.-H., Maghsoudlou, A., Matsumoto, M., Naser, N., Oben, B., Segev, O., Thielicke, M., Tong, X., Zivanovic, G., Manconi, R., Baguñà, J. & Riutort, M. (2022) Three dispersal routes out of Africa: A puzzling biogeographical history in freshwater planarians. Journal of Biogeography, 49 (7), 1219–1233. https://doi.org/10.1111/jbi.14371
- Song, X.-Y., Li, W.-X., Sluys, R., Huang, S.-X., Li, S.-F. & Wang, A.-T. (2020) A new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from China, with an account on the histochemical structure of its major nervous system. Zoosystematics and Evolution, 96 (2), 431–447. https://doi.org/10.3897/zse.96.52484
- Stocchino, G.-A., Corso, G., Manconi, R. & Pala, M. (2005) Endemic freshwater planarians of Sardinia: Redescription of Dugesia hepta (Platyhelminthes, Tricladida) with a comparison of the Mediterranean species of the genus. Journal of Natural History, 39, 1947–1960. https://doi.org/10.1080/00222930500060025
- Stocchino, G.-A., Sluys, R., Riutort, M., Solà, E. & Manconi, R. (2017) Freshwater planarian diversity (Platyhelminthes: Tricladida: Dugesiidae) in Madagascar: new species, cryptic species, with a redefinition of character states. Zoological Journal of the Linnean Society, 181 (4), 727–756. https://doi.org/10.1093/zoolinnean/zlx017
- Stocchino, G.-A., Sluys, R., Solà, E., Riutort, M. & Manconi, R. (2024) The long-eared freshwater planarians of Madagascar form a separate phylogenetic clade within the genus Dugesia (Platyhelminthes: Tricladida), with the description of two new species. Zoological Journal of the Linnean Society, 202, zlae143. https://doi.org/10.1093/zoolinnean/zlae143
- Tamura, K., Stecher, G., Peterson, D., Filipski, A. & Kumar, S. (2013) MEGA6: Molecular Evolutionary Genetics Analysis Version 6.0. Molecular Biology and Evolution, 30 (12), 2725–2729. https://doi.org/10.1093/molbev/mst197
- Wang, L., Chen, J.-Z., Dong, Z.-M., Chen, G.-W., Sluys, R. & Liu, D.-Z. (2021a) Two new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from the tropical monsoon forest in Southern China. ZooKeys, 1059, 89–116. https://doi.org/10.3897/zookeys.1059.65633
- Wang, L., Dong, Z.-M., Chen, G.-W., Sluys, R. & Liu, D.-Z. (2021b) Integrative descriptions of two new species of Dugesia from Hainan Island, China (Platyhelminthes, Tricladida, Dugesiidae). ZooKeys, 1028, 1–28. https://doi.org/10.3897/zookeys.1028.60838
- Wang, L., Wang, Y., Dong, Z., Chen, G., Sluys, R. & Liu, D. (2022) Integrative taxonomy unveils a new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from the southern portion of the Taihang Mountains in northern China, with the description of its complete mitogenome and an exploratory analysis of mitochondrial gene order as a taxonomic character. Integrative Zoology, 17 (6), 1193–1214. https://doi.org/10.1111/1749-4877.12605
- Wang, L., Zhu, S.-Q., Ma, F.-H., Li, X.-J., Zhao, Y.-H., Sun, X.-X., Li, N., Sluys, R., Liu, D.-Z., Dong, Z.-M., Chen, G.-W. & Dabert, M. (2024) Two new species of freshwater planarian (Platyhelminthes, Tricladida, Dugesiidae, Dugesia) from Southern China exhibit unusual karyotypes, with a discussion on reproduction in aneuploid species. Journal of Zoological Systematics and Evolutionary Research, 2024, 1–18. https://doi.org/10.1155/2024/8299436
- Wang, L., Chang, Y.-F., Sun, X.-X., Sluys, R., Liu, D.-Z., Dong, Z.-M. & Chen, G.-W. (2025) Two new species of Dugesia from Hainan Island and Leizhou Peninsula (Platyhelminthes, Tricladida, Dugesiidae). ZooKeys, 1233, 289–313. https://doi.org/10.3897/zookeys.1233.142976
- Winsor, L. & Sluys, R. (2018) Basic histological techniques for planarians. In: Rink, J.C. (Ed.), Planarian Regeneration: Methods and Protocols. Methods in Molecular Biology. Vol. 1774. Humana Press, Springer Science+Business Media, New York, New York, pp. 285–351. https://doi.org/10.1007/978-1-4939-7802-1_9
- Wu, F., Wang, L., Sluys, R., Sun, X.-X., Liu, D.-Z., Dong, Z.-M. & Chen, G.-W. (2025) An integrative analysis and account of two new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from the Hengduan Mountains, Southwest China, with reflections on the historical biogeography of Eastern Palearctic/Oriental lineages. Zoosystematics and Evolution, 101 (4), 1513–1529. https://doi.org/10.3897/zse.101.156742
- Yang, S., Yang, E.-L., Zhao, C.-W., Luo, G.-J., Ran, C., Zhang, S.-R., Xiong, L., Liao, J.-J., Du, C.-C., Li, Z.-L., Xue, Y.-Y., Long, M.-K., Li, M.-H., Luo, Q., Shen, X.-Q., Zhang, X.-Y. & Xie, Y.-H. (2024) How to identify karst priority ecological reserves. Ecological Frontiers, 44 (6), 1280–1290. https://doi.org/10.1016/j.ecofro.2024.08.004
- Zeng, Z.-Y., Wang, J., Sluys, R., Guo, Z.-P., Sun, T., Huang, X.-Z., Li, S.-F. & Wang, A.-T. (2024) Integrative description of a new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from Shennongjia, Central China. Zootaxa, 5406 (4), 535–550. https://doi.org/10.11646/zootaxa.5406.4.3
- Zhang, L., Liang, Z.-L., Fan, X.-P., Lu, N.-T., Zhou, X.-M., Wei, H.-J. & Zhang, L.-B. (2024) The Indo-Burma biodiversity hotspot for ferns: Updated phylogeny, hidden diversity, and biogeography of the java fern genus Leptochilus (Polypodiaceae). Plant Diversity, 46 (6), 698–712. https://doi.org/10.1016/j.pld.2024.08.005
- Zhu, Y., Huang, J., Sluys, R., Liu, Y., Sun, T., Wang, A.-T. & Zhang, Y. (2024) Integrative description of a new species of Dugesia (Platyhelminthes, Tricladida, Dugesiidae) from Southern China, with its complete mitogenome and a biogeographic evaluation. Zoosystematics and Evolution, 100 (1), 167–182. https://doi.org/10.3897/zse.100.114016
