A revision of the family Dissonidae Kurtz, 1924 (Copepoda: Siphonostomatoida)

Antimicrobial Potential of Aqueous Extract of Giant Sword Fern and Ultra-High-Performance Liquid Chromatography-High-Resolution Mass Spectrometry Analysis

Vibriosis and parasitic leech infestations cause the death of various farmed fish, such as groupers, hybrid groupers, sea bass, etc., in Malaysia and other Southeast Asian countries. In the absence of natural control agents, aquaculture operators rely on toxic chemicals to control Vibrio infections and parasitic leeches, which can have a negative impact on the environment and health. In the present study, we investigated the antivibrio and antiparasitic activities of the aqueous extract of giant sword fern (GSF) (Nephrolepis biserrata, Nephrolepidaceae, locally known as "Paku Pedang") against four Vibrio spp. and the parasitic leech Zeylanicobdella arugamensis, as well as its metabolic composition using the ultra-high-performance liquid chromatography-high-resolution mass spectrometry system (UHPLC-HRMS). The data show that the aqueous extract of GSF at a concentration of 100 mg/mL exhibits potent bactericidal activity against V. parahaemolyticus with a zone of inhibition of 19.5 mm. In addition, the extract showed dose-dependent activity against leeches, resulting in the complete killing of the parasitic leeches within a short period of 11-43 min when tested at concentrations ranging from 100 to 25 mg/mL. The UHPLC-HRMS analysis detected 118 metabolites in the aqueous extract of GSF. Flavonoids were the primary metabolites, followed by phenolic, aromatic, fatty acyl, terpenoid, vitamin and steroidal compounds. Notably, several of these metabolites possess antibacterial and antiparasitic properties, including cinnamaldehyde, cinnamic acid, apigenin, quercetin, cynaroside, luteolin, naringenin, wogonin, 6-gingerol, nicotinamide, abscisic acid, daidzein, salvianolic acid B, etc. Overall, our study shows the significant antibacterial and antiparasitic potential of the GSF aqueous extract, which demonstrates the presence of valuable secondary metabolites. Consequently, the aqueous extract is a promising natural alternative for the effective control of Vibrio infections and the treatment of parasitic leeches in aquaculture systems.

Parasitic copepods (Crustacea, Hexanauplia) on fishes from the lagoon flats of Palmyra Atoll, Central Pacific

We surveyed copepods parasitic on the fishes at Palmyra, a remote atoll in the Central Indo-Pacific faunal region. In total, we collected 849 individual fish, representing 44 species, from the intertidal lagoon flats at Palmyra and recovered 17 parasitic copepod species. The parasitic copepods were: Orbitacolaxwilliamsi on Mulloidichthysflavolineatus; Anuretesserratus on Acanthurusxanthopterus; Caligusconfusus on Carangoidesferdau, Carangoidesorthogrammus, Caranxignobilis, Caranxmelampygus, and Caranxpapuensis; Caliguskapuhili on Chaetodonauriga and Chaetodonlunula; Caliguslaticaudus on Rhinecanthusaculeatus, Pseudobalistesflavimarginatus, M.flavolineatus, Upeneustaeniopterus, Chrysipteraglauca, and Epinephalusmerra; Caligusmutabilis on Lutjanusfulvus and Lutjanusmonostigma; Caligusrandalli on C.ignobilis; Caligus sp. on L.fulvus; Caritusserratus on Chanoschanos; Lepeophtheiruslewisi on A.xanthopterus; Lepeophtheirusuluus on C.ignobilis; Dissonussimilis on Arothronhispidus; Nemesis sp. on Carcharhinusmelanopterus; Hatschekialongiabdominalis on A.hispidus; Hatschekiabicaudata on Chaetodonauriga and Chaetodonlunula; Kroyerialongicauda on C.melanopterus and Lernanthropus sp. on Kyphosuscinerascens. All copepod species reported here have been previously reported from the Indo-Pacific but represent new geographical records for Palmyra, demonstrating large-scale parasite dispersion strategies.

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

Two species of cucullanid nematodes collected from the intestine of marine fishes off New Caledonia were studied with the use of light and scanning electron microscopy (SEM): Dichelyne (Cucullanellus) bodiani n. sp. from Bodianus perditio (Quoy & Gaimard) (Perciformes: Labridae), characterised mainly by the small size of the body (males and gravid females 2.26-3.13 mm and 2.46-3.32 mm long, respectively), the presence of very long spicules (1.53-1.66 mm in length), the remarkably large seminal vesicle and the arrangement of caudal papillae, is the second known species of Dichelyne Jägerskiöld, 1902 parasitising fishes of the Labridae and the second nominal species of this genus recorded from fishes in New Caledonian waters. Cucullanus hansoni Olsen, 1952, originally described from Hawaii, is now, after 67 years, again reported from its type-host, Sufflamen fraenatum (Latreille) (Tetraodontiformes: Balistidae), from off New Caledonia. The SEM examination of C. hansoni, used in this species for the first time, revealed some new morphological details, such as the presence of a median precloacal cuticular elevation or the shape of deirids and distal tips of spicules, as well as the exact location of caudal papillae and phasmids in the male. This is the seventh species of Cucullanus Müller, 1777 recorded from fishes off New Caledonia.

The lunule of caligid copepods: an evolutionarily novel structure

Nearly half of the genera of the family Caligidae possess an evolutionarily novel structure called the "lunule" on the ventral surface of the frontal plate. Lunules are paired cup-like suckers that assist in securing attachment of the copepod parasite to its host. Although present in genera such as Caligus and Pseudocaligus, lunules are absent in other caligid genera such as Lepeophtheirus as well as in more primitive caligiforms such as members of the families Trebiidae and Dissonidae. We compared the morphology and development of the anterior margin of the frontal plates between two caligids, Pseudocaligus fugu and Lepeophtheirus sekii, and a more basal caligiform, Dissonus heronensis (a dissonid), using scanning electron, transmission electron, and laser confocal microscopes. Our observations suggest that the lunules originated as a modification of the marginal membranes of the ancestral frontal plates. We also demonstrated the presence of an anlagen cell population for the lunule and marginal membrane in the developing frontal plate. These primordial cells can be detected as early as the first stage of the chalimus phase. Based on these observations, an evolutionary scenario for the lunule is proposed based on cytological evidence. This case study enhances our understanding of "evolutionary novelty," which is a main focus of contemporary evolutionary developmental biology.

An annotated list of fish parasites (Isopoda, Copepoda, Monogenea, Digenea, Cestoda, Nematoda) collected from Snappers and Bream (Lutjanidae, Nemipteridae, Caesionidae) in New Caledonia confirms high parasite biodiversity on coral reef fish

BACKGROUND

Coral reefs are areas of maximum biodiversity, but the parasites of coral reef fishes, and especially their species richness, are not well known. Over an 8-year period, parasites were collected from 24 species of Lutjanidae, Nemipteridae and Caesionidae off New Caledonia, South Pacific.

RESULTS

Host-parasite and parasite-host lists are provided, with a total of 207 host-parasite combinations and 58 parasite species identified at the species level, with 27 new host records. Results are presented for isopods, copepods, monogeneans, digeneans, cestodes and nematodes. When results are restricted to well-sampled reef fish species (sample size > 30), the number of host-parasite combinations is 20-25 per fish species, and the number of parasites identified at the species level is 9-13 per fish species. Lutjanids include reef-associated fish and deeper sea fish from the outer slopes of the coral reef: fish from both milieus were compared. Surprisingly, parasite biodiversity was higher in deeper sea fish than in reef fish (host-parasite combinations: 12.50 vs 10.13, number of species per fish 3.75 vs 3.00); however, we identified four biases which diminish the validity of this comparison. Finally, these results and previously published results allow us to propose a generalization of parasite biodiversity for four major families of reef-associated fishes (Lutjanidae, Nemipteridae, Serranidae and Lethrinidae): well-sampled fish have a mean of 20 host-parasite combinations per fish species, and the number of parasites identified at the species level is 10 per fish species.

CONCLUSIONS

Since all precautions have been taken to minimize taxon numbers, it is safe to affirm than the number of fish parasites is at least ten times the number of fish species in coral reefs, for species of similar size or larger than the species in the four families studied; this is a major improvement to our estimate of biodiversity in coral reefs. Our results suggest that extinction of a coral reef fish species would eventually result in the coextinction of at least ten species of parasites.

Huffmanela plectropomi n. sp. (Nematoda: Trichosomoididae: Huffmanelinae) from the coralgrouper Plectropomus leopardus (Lacépède) off New Caledonia

Huffmanela plectropomi n. sp. is described from eggs only, which were found in black spots in the mesentery of a coralgrouper, Plectropomus leopardus (Lacépède), caught near Nouméa, New Caledonia, South Pacific. The eggs are 64-76 (mean 69) μm in length and 29-35 (mean 32) μm in width, with a thin shell. The surface of the eggs bears a thick, continuous layer of filaments. The species is distinguished from other members of the genus by the dimensions of its eggs and the characteristics of their surface. This is the first species of Huffmanela Moravec, 1987 to be described from a grouper (Serranidae, Epinephelinae).

An annotated list of parasites (Isopoda, Copepoda, Monogenea, Digenea, Cestoda and Nematoda) collected in groupers (Serranidae, Epinephelinae) in New Caledonia emphasizes parasite biodiversity in coral reef fish

Abstract: Over a 7-year period, parasites have been collected from 28 species of groupers (Serranidae, Epinephelinae) in the waters off New Caledonia. Host-parasite and parasite-host lists are provided, with a total of 337 host-parasite combinations, including 146 parasite identifications at the species level. Results are included for isopods (5 species), copepods (19), monogeneans (56), digeneans (28), cestodes (12), and nematodes (12). When results are restricted to those 14 fish species for which more than five specimens were examined and to parasites identified at the species level, 109 host-parasite combinations were recorded, with 63 different species, of which monogeneans account for half (32 species), and an average of 4.5 parasite species per fish species. Digenean records were compared for 16 fish species shared with the study of Cribb et al. (2002); based on a total of 90 parasite records identified at the species level, New Caledonia has 17 new records and only seven species were already known from other locations. We hypothesize that the present results represent only a small part of the actual biodiversity, and we predict a biodiversity of 10 different parasite species and 30 host-parasite combinations per serranid. A comparison with a study on Heron Island (Queensland, Australia) by Lester and Sewell (1989) was attempted: of the four species of fish in common and in a total of 91 host-parasite combinations, only six parasites identified at the species level were shared. This suggests strongly that insufficient sampling impairs proper biogeographical or ecological comparisons. Probably only 3% of the parasite species of coral reef fish are already known in New Caledonia.

A new genus of sea louse (Copepoda:Siphonostomatoida: Caligidae) parasitic on the bluespine unicornfish (Naso unicornis)

A new genus, Alanlewisia, of the family Caligidae is established to accommodate a sea louse species originally, but tentatively, placed in the genus Lepeophtheirus by Lewis (1967). The type species is Alanlewisia fallolunulus (Lewis, 1967) comb. n., which is redescribed in detail based on new material collected from bluespine unicornfish, Naso unicornis (Forsskål), caught off New Caledonia in the South Pacific. This species was originally described by Lewis (1967) under the binomen Lepeophtheirus? fallolunulus from the same host species collected in Hawaii. This species was subsequently transferred to the genus Anuretes by Ho and Lin (2000). Lewis was uncertain of the generic placement primarily because of the possession, in the females only, of paired lunule-like structures on the ventral surface of the modified frontal plates. In both sexes the first swimming leg is biramous, with a well-developed endopod bearing 2 long, sparsely-plumose setae, and the third leg has a 2-segmented exopod. This combination of characters serves to differentiate the new genus from existing genera. Preliminary phylogenetic analysis suggests that the new genus represents an early offshoot from the main caligid lineage, basal to the Paralebion-Tuxophorus-Caligus clade identified by Boxshall and Justine (2005).