Integrative approach for discovering of the new species within the genus Allocreadium Looss, 1900 (Trematoda: Allocreadiidae) and framing of biogeographical hypotheses for the genus

Morphological and molecular evidence for the recognition ofAllocreadium bursensisn. sp. (Trematoda: Allocreadiidae) from Angora loachOxynoemacheilus angoraefrom Turkey

“…Based on our molecular genetic data, we conclude that the divergence of the Allocreadium species did not occur exceptionally linearly from East Asia to the West, as was previously stated (Bogatov & Vainutis 2022; Vainutis et al 2023). It is likely that the ‘ A. isoporum ’ reported from Turkey (Aydogdu et al 2018) is the newly described A. bursensis n. sp.…”

“…Internal resolution of the genus Allocreadium on the BI and MP phylogenetic reconstructions (Figures 2a,b) and distribution of its species into groups a – h completely corresponds, as previously shown, with the studies of Vainutis (2020) and Vainutis et al (2023). The NJ tree showed the same topology within the clade of Allocreadium as that presented in study of Dos Santos et al (2021), but statistical support for such a division (subclades h and b – g ) was lower than 50% (Figure 2c).…”

“…(Vainutis et al . 2023), A. bursensis is closer to the Japanese species A. aburahaya by general morphology. However, the Turkish species differs from the Japanese one in these characteristics: entire ellipsoid testes vs. slightly indented irregularly; entire subspherical ovary vs. globular or somewhat irregular ovary; eyespots absent vs. scattered in the forebody.…”

“…The general morphology of Allocreadium bursensis n. sp. is closest to that of 15 species including ten that represent the Palearctic Allocreadium spp., which are arranged in the keys of Vainutis et al (2023). Generally, the differentiation of the species was based on a combination of external (ventral and oral suckers’ ratio; body length and width; and its ratio to forebody) and internal (cirrus pouch configuration; uterine extension in hindbody; egg size; disposition of anterior border of vitellarium; esophagus length) features.…”

“…Allocreadium isoporum (Looss 1894) Looss, 1902 was described from nine freshwater fish species in Turkey (Aydogdu et al 2002; Koyun & Altunel 2007; Öztürk 2014; Koyun et al 2015, 2016; Aydogdu et al 2018), whereas A. lobatum Wallin, 1909 was recorded only from Blicca bjoerkna in the Sakarya River by Akmirza and Yardimci (2014). In recent phylogenetic studies nine valid species of Allocreadium have been confirmed: A. isoporum , A. lobatum , A. gotoi (Hasegawa & Ozaki, 1926) Shimazu, 1988, A. crassum (Wesenberg-Lund, 1934), A. neotenicum Peters, 1957, A. hemibarbi Roitman, 1963, A. khankaiensis Vainutis, 2020, A. apokryfi Dos Santos, Gilbert, Avenant-Oldewage & Dumbo, 2021, A. pseudoisoporum Vainutis, Voronova, Urabe & Kazarin, 2023 (Vainutis 2020; Dos Santos et al 2021; Vainutis et al 2023).…”