Paradiplozoon cirrhini n. sp. (Monogenea, Diplozoidae), a gill parasite of Cirrhinus molitorella (Cyprinidae, Labeoninae) in South China

Abstract

Paradiplozoon cirrhini n. sp. (Monogenea, Diplozoidae) is described from the gills of mud carp, Cirrhinus molitorella (Valenciennes, 1844) (Cyprinidae, Labeoninae), collected in Wuzhou, Guangxi Province, and Conghua, Guangdong Province as part of an ongoing survey of the diplozoid fauna in the Pearl River basin of China. The new Paradiplozoon species is distinguished from congeners by the structure of median plate and its outgrowth sclerites. The ITS2 sequences of the new species differ from all known available diplozoid sequences by 22.04%–38.34%. The new species is the first diplozoid species parasitic on Labeoninae in China. Molecular phylogenetic analyses using rRNA ITS2 placed Paradiplozoon cirrhini n. sp. in a sister position to the other Chinese Paradiplozoon, implying that Labeoninae represents an early and potentially ancestral host group for China Paradiplozoon. We also provided ITS2 sequences for four other diplozoids species, namely P. megalobramae Khotenovsky, 1982, P. saurogobionis (Jiang, et al., 1985) Jiang, Wu & Wang, 1989, Sindiplozoon hunanensis Yao & Wang, 1997, and Sindiplozoon sp., and validated their phylogenetic position. The results confirm that all diplozoid species are spilt into two major clades and show monophyly of Sindiplozoon but paraphyly of Paradiplozoon.

Gill parasites of Schizocypris altidorsalis (Pisces: Cyprinidae), a threatened freshwater fish in Iran

“…The phylogenetic position of Paradiplozoon jalalii in the ITS2 tree (Fig. 5c) suggests that this species belongs to the genus Paradiplozoon, a paraphyletic genus (Huang et al 2023). The present species is a sister of Eudiplozoon in the 28S and 18S trees (Fig.…”

“…The preserved parasites were then sent to Shamsi's Parasitology Laboratory at Charles Sturt University, Australia, where the specimens underwent morphological examination and molecular analyses of their taxonomic classification and genetic characteristics. Parasites were morphologically examined as previously described by Gussev (1983) and Jalali et al (2005), and identified in accordance with previous publications (Galli et al 2010;Huang et al 2023;Nejat et al 2023). The terminology to describe various body-part structures is mainly in accordance with Galli et al (2010).…”

“…Closely related species of Monogenea were used as outgroup. For ITS-2 tree, analysing of phylogenetic trees built in previous works (Huang et al 2023;Nejat et al 2023) for Paradiplozoon spp. was useful as well.…”

“…The pairwise comparison using the p-distance model in MEGA 10 was performed to evaluate the genetic distance between the sequences. After analysing phylogenetic trees built in previous works (Huang et al 2023;Nejat et al 2023) for Paradiplozoon spp., a closely related species of Monogenea, Octomacrum europaeum, was selected as an outgroup. Details of the sequences used to build phylogenetic trees in the present study can be found in Table 1.…”

“…Paradiplozoon stands out as the most diverse genus within the Diplozoinae subfamily, and its distinguishing feature for species indentification is primarily associated with its clamp structure. Specifically, the key morphological components include the median sclerite and its associated structures, such as the trapeze spur, as well as the anterior and posterior joining sclerites (Matejusová et al 2004;Dos Santos et al 2015;Huang et al 2023). There are two distinct species of Paradiplozoon that parasitise Schizothorax spp., namely, Paradiplozoon schizothorazi (Iksanov, 1965) and P. yarkandense (Galli et al 2010;Arken et al 2022).…”