Morphological and molecular description of Allocreadium apokryfi sp. n. (Digenea: Allocreadiidae) from native Labeobarbus aeneus (Cyprinidae) in South Africa, including notes on its biology, evolutionary history and an updated key of African Allocreadium

Abstract

Adult trematodes of Allocreadium Looss, 1900 (Digenea) infect the intestine of mostly freshwater fishes in Asia, Europe, Africa and the Americas. During routine parasitological surveys in the Vaal River system, adult trematodes were collected from the intestine of smallmouth yellowfish, Labeobarbus aeneus (Burchell). The trematodes were confirmed to represent a member of Allocreadium and did not match any existing taxon. Therefore, they are described as a new species, Allocreadium apokryfi sp. n. The morphology of the new species most closely resembles that of Allocreadium aswanense El-Naffar, Saoud et Hassan, 1984, but it differs from it by having a bipartite internal seminal vesicle, wider eggs, a shorter intertesticular distance, an intestinal bifurcation at the ventral sucker level, a ventral sucker that is larger than the oral sucker, and a genital pore near the intestinal bifurcation or the ventral sucker. The surface topology of the new species is notably different from that of other allocreadiids. Papillae were observed in the ventral sucker and surrounding both ventral and oral suckers, but the number and arrangement of the latter were not consistent among specimens. The protruding cirrus of A. apokryfi sp. n. was described using SEM and is the first such observation for the genus. Genetic characterisation showed that the new species was clearly distinct from other Allocreadium spp. using both 18S (nucleotide difference 1.3-9.1%) and 28S (4.7-6.5%) rDNA, forming a well-supported clade in Allocreadium. The presence of A. apokryfi sp. n. in a well-studied river is unexpected, and considering the diet of its host and the scarcity of Allocreadium in Africa, the possible biology of this species is discussed herein.

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

“…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). The African species Allocreadium apokryfi recently described by Dos Santos et al (2021) had a variable position on the reconstructed phylogenetic trees (Figures 2a–d). In the original description, A. apokryfi was nested between the branches of A. pseudoisoporum ( Allocreadium sp.)…”

“…In the original description, A. apokryfi was nested between the branches of A. pseudoisoporum ( Allocreadium sp.) and A. gotoi based on the BI and ML models with equivocal support for such a resolution (0.8 posterior probabilities/53%) (Dos Santos et al 2021). Such topology corresponds to the tree reconstructed with NJ method but was not supported by us (Figure 2c).…”

“…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).…”

Neglected symbionts and other metazoan invertebrates associated with molluscs from Africa's largest lake: Diversity, biotic interactions and bioindication

“…However, these reports are from North America and Europe. In Africa, although the adults of allocreadiids, bucephalids and gorgoderids occur in freshwater fishes (Dos Santos et al, 2021; Paperna, 1996; Zhokhov, 2010), their intermediate hosts remain largely unknown. In the current study, gorgoderid larvae were found in Coelatura spp.…”

Chelatrematidae n. fam., a new family of digenetic trematodes from the South Western Ghats, India, erected on the basis of morphological and molecular studies

“…Cases of close relationships of trematodes from Eurasian and North American continents have been observed for gorgoderoids. For example, detailed phylogenetic analysis of Allocreadiidae indicated such relationships, where North American species belong to a terminal clade, sister to Asian and European species within this family (Soldánová et al, 2017;Petkevičiūtė et al, 2018;Atopkin et al, 2020;Faltýnkova et al, 2020;Vainutis et al, 2021;Bogatov & Vainutis, 2022). However, lack of molecular data on species, closely related to C. neilgherriensis and P. limi as well as for type-species of Chelatrema is a barrier to clarify these relationships.…”