Taxonomic Status of Diplectanum robustitubum Wu & Li, 2003 (Monogenoidea: Diplectanidae) from the Purple-Spotted Bigeye Priacanthus tayenus (Priacanthidae) and the Description of Platycephalotrema parile n. sp. (Monogenoidea: Dactylogyridae) from the Bartail Flathead Platycephalus indicus (Platycephalidae), in the Arabian Gulf

Acta Parasitologica (2024) 69:1295–1303 https://doi.org/10.1007/s11686-024-00849-4 ORIGINAL PAPER Taxonomic Status of Diplectanum robustitubum Wu & Li, 2003 (Monogenoidea: Diplectanidae) from the Purple‑Spotted Bigeye Priacanthus tayenus (Priacanthidae) and the Description of Platycephalotrema parile n. sp. (Monogenoidea: Dactylogyridae) from the Bartail Flathead Platycephalus indicus (Platycephalidae), in the Arabian Gulf Delane C. Kritsky1 · Ali Adnan Al‑Darwesh2 · Atheer H. Ali3 Received: 23 February 2024 / Accepted: 15 April 2024 / Published online: 25 May 2024 © The Author(s) 2024 Abstract Purple-spotted bigeyes Priacanthus tayenus Richardson (Priacanthidae) and bartail flathead Platycephalus indicus (Linnaeus) (Platycephalidae) were collected from the Arabian Gulf and examined for species of Monogenoidea (Polyonchoinea) from February to December 2020. Diplectanum robustitubum Wu & Li, 2003 and an undescribed species of Platycephalotrema Kritsky & Nitta, 2019 were recovered from the gill lamellae of these hosts, respectively. Diplectanum robustitubum from Iraq was redescribed and transferred to Oliveriplectanum Domingues & Boeger, 2008 (Diplectanidae) as Oliveriplecta num robustitubum (Wu & Li, 2003) n. comb. Platycephalotrema parile n. sp. (Dactylogyridae) from Iraq and Kuwait was described and differentiated from the similar species, Haliotrema indicum Tripathi, 1959, Platycephalotrema ogawai Kritsky & Nitta, 2019, and Platycephalotrema platycephali (Yin & Sproston, 1948) Kritsky & Nitta, 2019, based primarily on the comparative morphologies of the vaginal sclerites. Haliotrema indicum was transferred to Platycephalotrema as Platycepha lotrema indicum (Tripathi, 1959) n. comb. and Haliotrema swatowense Yao, Wang, Xia, & Chen, 1998 was considered a junior subjective synonym of P. indicum. The finding of O. robustitubum in the Arabian Gulf represents a new geographic record for the species. Background The present paper represents the third installment concerning the monogenoids collected during surveys to explore their diversity on the marine and freshwater fishes of Iraq. Previous installments on the monogenoids emanating from the surveys included the dactylogyrid and gyrodactylid species parasitizing mugilid fishes. Purpose The purpose of this paper is to further document the diversity of monogenoids infecting the fishes of Iraq. Methods Marine fishes were necropsied for parasites, and standard procedures for collecting, mounting, drawing, and measuring of monogenoids were employed. Results Oliveriplectanum robustitubum n. comb. (Diplectanidae) and Platycephalotrema parile n. sp. (Dactylogyridae) were collected. The occurrence of O. robustitubum in the Arabian Gulf represented a new locality record for the species. Conclusion The recorded presence of O. robustitubum and P. parile n. sp. suggests that the diversity of monogenoids in Iraq is under estimated in the literature. Keywords Arabian Gulf · Dactylogyridae · Diplectanidae · Haliotrema swatowense · Iraq · Kuwait · Monogenoidea · Oliveriplectanum robustitubum n. comb. · Platycephalotrema indicus n. comb. · Platycephalotrema parile n. sp. · Platycephalus indicus · Priacanthus tayenus ZooBank registration: urn:lsid:zoobank.org:pub:EE6F0F4F-CC3D41D9-BFE1-0DDB5B8EFC5E. Extended author information available on the last page of the article Vol.:(0123456789) 1296 Acta Parasitologica (2024) 69:1295–1303 Introduction Materials and Methods The diversity of monogenoids infecting the marine fishes of Iraq is poorly documented and continues to receive minimal attention by investigators. Ali et al. [4] reported that 322 species of marine fishes had been recorded in the territorial marine waters, marshes, and the lower reaches of the Euphrates and Tigris Rivers of Iraq during the period of 1874 to mid-2018, whereas Mhaisen et al. [17] listed only 21 fully identified valid species of Monogenoidea (including one species considered spe cies inquirenda) having been recorded from these fishes through 2017. Since the list of Mhaisen et al. [17], three species of Diplectanidae infecting marine fishes of Iraq have been added: Lamellodiscus indicus Tripathi, 1959 from the haffara seabream Rhabdosargus haffara (Forsskål) and goldlined seabream Rhabdosargus sarba (Forsskål) (both Sparidae) [2], Protolamellodiscus seni lobatus Kritsky, Jiménez-Ruiz and Sey, 2000 from the king soldierbream Argyrops spinifer (Forsskål) (Sparidae) [2], and Calydiscoides difficilis (Yamaguti, 1953) Young, 1969 from the pink ear emperor Lethrinus lentjan (Lacepède), the spangled emperor Lethrinus nebulosus (Forsskål) (both Lethrinidae), and the areolate grouper Epinephelus areolatus (Forsskål) (Epinephelidae) [3]. The latter three species were included in the 12 dactylogyrid and 16 diplectanid species recorded and/or described from Iraqi marine fishes in an unpublished thesis by Al-Darwesh [1]. In the present paper, the taxonomic status of the diplectanid Diplectanum robustitubum Wu & Li, 2003 and that of the dactylogyrid Platycephalotrema parile n. sp. are evaluated. Both helminths occur on the gill lamellae of marine fishes of Iraq: D. robustitubum on the purple-spotted bigeye Priacanthus tayenus Richardson (Priacanthidae) and Pt. parile n. sp. on the bartail hardhead Platycephalus indicus (Linnaeus) (Platycephalidae). The respective hosts occur naturally throughout much of the Indo-West Pacific Ocean, where both are commercially important. Although less so in other regions, bigeyes comprise a significant component of the trawl fishery of southeast Asia, particularly in the areas if the Andaman Sea and the southern region of the South China Sea [23]. Within the middle eastern region of Asia, the bartail flathead is the most common flathead appearing in markets [9], where it is sold as a very palatable food fish [5]; the flathead is also a component of Chinese medicine [24]. Specimens of the purple-spotted bigeye and the bartail hardhead were collected off the southern marine coast of Iraq near the mouth of the Shatt Al-Arab River (29°53′–29°85′N, 48°13'–48°40′E) by fishermen using trawl nets during February through December, 2020, where salinity levels varied between 24.5–32.5 PSU. Fish hosts were identified using Carpenter et al. [9],the higher classification for the fishes was that presented by Betancur-R et al. [6],and common and scientific names of fishes were verified using Froese & Pauly [12] and Fricke et al. [11], respectively. The fishes were transported in an icebox filled with crushed ice to the laboratory located in Basrah, Iraq, and examined for monogenoids within 48 h of capture. Gill baskets were removed and place in vials containing a hot (~ 60 C) 5% formalin (2% formaldehyde) solution for relaxation and fixation of monogenoids. The vials were labeled and then shaken to ensure suitable fixation and removal of helminths from the gill tissues. Helminths were subsequently picked from the gills or usually from the sediment using (...truncated)