Dichelyne (Cucullanellus) bodiani n. sp. and Cucullanus hansoni Olsen, 1952 (Nematoda: Cucullanidae) from fishes off New Caledonia

Cucullanus bulbosus (Lane, 1916) Barreto, 1918 (Nematoda, Cucullanidae) from the common ponyfish Leiognathus equulus (Leiognathidae): Morphology and molecular study

The common ponyfish Leiognathus equulus is a marine fish species with very high commercial value. Little information is available about its parasitic infections. Based on light and scanning electron microscopy, as well as sequencing and analysis of the partial regions of the ITS-1, 18S rRNA, COX1 genes, were employed for the systematic evaluation of a nematode parasite, which it first isolated from L. equulus in Jeddah Province, Red Sea, Saudi Arabia. Results revealed that this nematode parasite closely resembles the previously described Cucullanus bulbosus. Microscopic examination showed that it distinguished from congeners by the unique structure of hemispherical elevation at pseudobuccal capsule level, the ratio of esophagus/body length, spicules size, presence of pre-cloacal sucker, rod-shaped gubernaculum, and the arrangement of caudal papillae in males. Phylogenetic analyses based on ITS-1, 18S rRNA, and COX1 gene regions were constructed to investigate phylogenetic relationships between this parasite species and other related taxa. Results supported that Cucullanus bulbosus resembles a sister of Cucullanus genypteri, Cucullanus pulcherrimus, Cucullanus bourdini, Cucullanus extraneus, and Cucullanus hainanensis by using different genetic markers. This study provides more information about combining morphological and molecular data to identify Cucullanus species with the first natural occurrence in the common ponyfish inhabited in Saudi Arabia.

New records of cucullanid nematodes from marine fishes off New Caledonia, with descriptions of five new species of Cucullanus (Nematoda, Cucullanidae)

Recent examinations of cucullanid nematodes (Cucullanidae) from marine fishes off New Caledonia, collected in the years 2004–2009, revealed the presence of the following five new species of Cucullanus Müller, 1777, all parasitic in Perciformes: Cucullanus variolae n. sp. from Variola louti (type host) and V. albimarginata (both Serranidae); Cucullanus acutospiculatus n. sp. from Caesio cuning (Caesionidae); Cucullanus diagrammae n. sp. from Diagramma pictum (Haemulidae); Cucullanus parapercidis n. sp. from Parapercis xanthozona (type host) and P. hexophtalma (both Pinguipedidae); and Cucullanus petterae n. sp. from Epinephelus merra (type host) and E. fasciatus (both Serranidae). An additional congeneric species, Cucullanus bioccai Orecchia et Paggi, 1987 was recorded from Mugil cephalus (Mugilidae, Mugiliformes) (first record in the Pacific Ocean) and Cucullanus sp. (only female) was found in Arothron manilensis (Tetraodontidae, Tetraodontiformes). Furthermore, two known cucullanid species, Dichelyne (Cucullanellus) branchiostegi (Yamaguti, 1941) in Branchiostegus wardi (Malacanthidae, Perciformes) (new host and geographical records) and Dichelyne (Cucullanellus) bodiani Moravec et Justine, 2019 in Bodianus busellatus (new host) and B. perditio (both Labridae, Perciformes), were found; Dichelyne (Cucullanellus) sp. (only females) coinfecting the latter host may represent an unknown species. Most species are described based on light and electron microscopical studies. The specimens described by Xu et al., 2017 as Cucullanus bourdini Petter et Le Bel, 1992 from Caesio xanthonota (Caesionidae) in the Taiwan Strait are considered to represent a new species, for which the name Cucullanus sinensis n. sp. is proposed.

Some adult and larval nematodes from fishes off New Caledonia

A collection of nematodes from the Muséum National d'Histoire Naturelle (National Museum of Natural History), Paris, France, was studied. The nematodes had previously been collected from a range of marine fish hosts. The aim of this study was to investigate the identity of these nematodes. Detailed body measurements of the nematodes were taken via light microscopy and where possible first and second internal transcribed spacers (ITS-1 and ITS-2) of ribosomal DNA were subjected to PCR, purified and sequenced. Six species and three larval types were found from a range of fish species and included 13 new host records and two new geographical records. Of the taxa found, Hysterothylacium kajikiae is the only species which may have zoonotic potential. The majority of host fish in this study are edible species, commercially and recreationally fished and frequently incorporated into the cuisine of New Caledonia as raw fish dishes. This study will allow better understanding of the diversity, life cycles, distribution and host-parasite relationships in the New Caledonia area.