Caligus madeirensis sp. nov. (Copepoda: Caligidae) Parasitic on Pompano, Trachinotus ovatus (Linnaeus, 1758), from Eastern Atlantic Waters, Surrounding the Madeira Archipelago, Portugal
ABSTRACT: Introduction A new species of the genus Caligus is described based on specimens collected from pompano, Trachinotus ovatus (Linnaeus), caught in eastern Atlantic waters, near the Madeira archipelago. Methods Pompano (n?=?21) were purchased from the local fish market and examined for parasitic copepods. Morphological features of the copepods were examined and drawn using an Olympus BX51 equipped with a drawing tube. Key diagnostic characters were scanned using a confocal laser scanning microscope and a scanning electron microscope. Results Caligus madeirensis sp. nov., can be distinguished from all congeners (270 spp.) by the combination of the following characters: (i) an accessory process on the 3 outer terminal spines located on the distal exopodal segment of leg 1, (ii) a mandible with 14 teeth, (iii) a sternal furca with parallel, spatulate tines, (iv) a maxilliped with 2 simple setae at base of a claw, (v) a leg 3 with second endopodal segment with 5 pinnate setae, (vi) a 2-segmented leg 4 exopod with I; III spine formula, (vii) a male antenna with 4 overlapping plates on the distal segment, (viii) a male maxilliped corpus bearing a prominent myxal process ornamented with dense corrugations along inner margin. Conclusion Together with Caligus madeirensis sp. nov., the Caligus fauna of Portugal consists of 13 species reported from 17 Portuguese marine fishes. Considering the large number of marine fish species (510 spp.) currently recorded from Portuguese waters it seems that only 3.3% of the Portuguese marine fishes have been found to be infested with species of the genus Caligus O.F. Müller, 1758, the result of which, however, might be due to limited sampling. Electronic supplementary material The online version of this article (10.1007/s11686-020-00290-3) contains supplementary material, which is available to authorized users.
Project description:A new genus and species of calanoid copepods belonging to the group of Bradfordian families, Pogonura rugosa gen. et sp. nov., is described from the deep-sea hyperbenthic layers off Nagannu Island, Okinawa Prefecture, southwestern Japan. Pogonura gen. nov. is similar to another Bradfordian genus Procenognatha in sharing the following characteristics: (1) segmentation of the antennule, fused segments II-IV, X-XI, XXVII-XXVIII in females and II-IV, X-XII, XXVII-XXVIII, right XXII-XXIII in males; (2) retained setae on the ancestral segments I-IV of the antennary exopod; (3) setules on the mandibular gnathobase; (4) 3 sclerotized setae on the maxillary endopod; (5) absence of sensory seta on the maxilliped; (6) large spinules on the posterior surface of the rami of legs 2 and 3; and (7) setation and segmentation of female leg 5. Pogonura gen. nov. is distinctly distinguished from Procenognatha by the following features: (1) reduction of a seta on the ancestral segment IX of the antennary exopod, (2) 8 setae (7 in Procenognatha) on the maxillular exopod, (3) 5 brush-like setae (6 in Procenognatha) on the maxillary endopod, and (4) reduction of right endopod of male leg 5. The systematic position of Pogonura gen. nov. in the Bradfordian families is also discussed. Although this new genus shares synapomorphies with some diaixid genera, an assignment of this genus to any Bradfordian family should be pending until the taxonomy of this family group is clearly settled.
Project description:A new species, Boholina reducta sp. nov., was found in a brackish pool within an anchialine cave in Tra Ban Island in Bai Tu Long Bay, north Vietnam. The new species is clearly distinguished from all the six species currently known in the genus Boholina by the following unique characteristics: reduction of the septum between gonopores; narrow and pointed rostrum; basal segment of mandibular palp armed with three setae; maxillule without seta on the basal exite, and exopod with 11 setae; second and third endopodal segments of the maxilliped bearing three setae each; exopod of male right leg 5 2-segmented, with two strong and one vestigial spines on the outer margin of the distal segment; and last exopodal segment of female leg 5 bearing only one spine on the outer margin. We provide a description of the new species, along with detailed illustrations and scanning electron microscopy photographs. The identification key to Boholina species is updated as well. This is the first record of the genus Boholina from Vietnam.
Project description:During the analysis of phytal meiobenthic samples collected from a rocky-sandy beach in the state of Nayarit, in the Mexican Pacific, several specimens of harpacticoid copepods were obtained and taxonomically examined. These specimens were found to represent an undescribed species of the peltidiid genus Peltidium Philippi, 1839. The new species, Peltidium nayarit sp. n. is described herein. It resembles Peltidium nichollsi Geddes and Peltidium lerneri Geddes from Bahamas but also the widespread Peltidium speciosum Thompson & Scott and Peltidium purpureum Philippi. The new species from the Mexican Pacific differs from its known congeners by its possession of a unique combination of characters, including a modified pectinate seta on the antennary exopod, three terminal setae on the second endopodal segment of leg 1, third exopodal segment of leg 1 with three elements, inner terminal claw twice as long as outer claw, female fifth leg with 5 exopodal setae, exopodal setae I-III stout, spinulose and seta IV being as long as seta V. This is the second species of the family known to be distributed in the Eastern Tropical Pacific and in Mexico. Pending additional data, the distribution of this species appears to be restricted to this area of the Mexican Pacific.
Project description:A 2016 collaborative survey of commercial fish parasites in Moreton Bay, Queensland, Australia led to the discovery of two new species of parasitic copepods belonging to the family Bomolochidae. Females of Nothobomolochus johndaveorum n. sp. were found attached to the gill filaments of Gerres subfasciatus and Gerres oyena. The new species most closely resembles N. leiognathicola and N. quadriceros. All 3 species possess 3 modified setae on the first antennulary segment that are approximately the same length and have a robust seta on the second antennulary segment adjacent to the 3 modified setae giving a superficial appearance of 4 modified setae on the antennule. The new species can be distinguished from these two species in its possession of longer inner setae on the first two endopodal segments of leg 4: the seta on endopodal segment 1 extends past the midline of the distal segment in the new species vs to the proximal margin of the distal segment in the other two species, and the seta on segment 2 extends well beyond the distal margin of the endopod in the new species vs just to the margin in the other two species. Females and males of Unicolax longicrus n. sp. were found in the nasal sinuses of Sillago maculata and Sillago ciliata. The new species differs from 6 of its 7 congeners in having a leg 4 exopod formula of II, I, 4 rather than II, I, 3 or II, I, 5. The new species resembles U. anonymous in this feature, but differs in its possession of a leg 5 that is relatively longer and less wide, and, whereas U. anonymous possesses inner and outer distal spines on leg 5 that are approximately the same length, those of the new species are relatively longer and asymmetrical. Unicolax longicrus n. sp. is unique among its congeners in its possession of a leg 4 with highly elongated endopodal segments 2 and 3, from which its name is derived. In addition to describing the two new species, host and locality reports for all species of Nothobomolochus and Unicolax are reviewed.
Project description:BACKGROUND: The Caligidae is a family of parasitic copepods containing over 30 recognised genera. They are commercially important parasites as they cause disease in numerous finfish aquaculture facilities globally. Morphological features are used to distinguish between the genera and Pseudocaligus has traditionally been differentiated from Caligus solely by the presence of a much reduced form of the fourth thoracic leg. Currently there are numerous DNA sequences available for Caligus spp. but only the type species, Pseudocaligus brevipedis, has molecular data available, so systematic studies using molecular phylogenetic analyses have been limited. METHODS: Three gene regions, SSU rDNA, 16S and CO1, for Pseudocaligus fugu from puffer fish from Japan and Pseudocaligus uniartus from rabbit fish from Indonesia are sequenced and molecular phylogenetic analyses performed in order to infer phylogenetic relationships between Pseudocaligus and other caligid copepods. RESULTS: The analysis revealed that there was no discrete grouping of Pseudocaligus spp. and that they had a polyphyletic distribution within Caligus taxa. Pseudocaligus fugu grouped with Caligus elongatus and contained a unique synapomorphy in the SSU rDNA region only seen in members of that clade. Pseudocaligus uniartus formed a well-supported group, in the SSU rDNA analyses, with a Caligus sp. that also infects rabbit fish, but was unresolved in the other analyses. Pseudocaligus brevipedis consistently and robustly grouped with Caligus curtus and C. centrodonti in all analyses. The majority of Lepeophtheirus spp. form a monophyletic sister group to the Caligus clade; however, L. natalensis is unresolved in all analyses and does not form part of the main Lepeophtheirus clade. CONCLUSIONS: These findings do not support the morphological-based distinction between Pseudocaligus and Caligus, suggesting that the reduced fourth leg is a feature that has evolved on multiple occasions throughout caligid evolution. Congruent molecular phylogenetic data support groupings based on the presence of morphological features, such as lunules, geography and host fish type rather than appendage morphology. Therefore, we support the synonymy of Pseudocaligus with Caligus.
Project description:Redescriptions of two pennellid copepods, Peniculus minuticaudae Shiino, 1956 and Peniculus truncatus Shiino, 1956, are provided, based on postmetamorphic adult females collected from marine ranched fishes captured at Tongyeong marine living resources research & conservation center, Korea. Peniculus minuticaudae was collected from the soft fin rays of black scraper Thamnaconus modestus. It can be distinguished from the other two closely related congeners Peniculus ostraciontis Yamaguti, 1939 and Peniculus truncatus by having a well developed triangular-shaped abdomen; the abdomen is rudimentary in other two species. This is thefirst report of the occurrence of Peniculus minuticaudae in Korea. Peniculus truncatus was collected from the dorsal fin of Korean rockfish Sebastes schlegelii. It can be distinguished from Peniculus minuticaudae by the combination of a rudimentary abdomen, long neck and setae on leg 1 and from Peniculus ostraciontis by the long neck, slender trunk, and setae on leg 1. It is also shown that Peniculus truncatus captured from the same host in Korea was misidentified as Peniculus ostraciontis and hence, this is thesecond record of the occurrence of Peniculus truncatus in Korea. A key is provided for the 14 nominal species of Peniculus.
Project description:Soyer, 1964 known from Banyuls-sur-Mer only. The latter two species can be separated by the armature complement of the syncoxa of the maxilliped, by the structure of the antenna, and by the inner armature complement of the third exopodal segment of the fourth swimming leg.
Project description:Two populations of new species are described for Hexapleomera Dudich, 1931 from the southeastern coast and Jeju island of South Korea (north west Pacific). The specimens were collected using a light trap set overnight at the entrance near a pier or harbour. Hexapleomera ulsanasp. n. is clearly differentiated from other species in the genus by the uropod with five articles, a maxillule palp with four distal setae, the maxilliped coxa with three proximal setae, the epignath with short and blunt spiniform seta, the propodus of pereopods 2-3 with three ventral setae, and the maxilla with a rugged shape of the distal margin. Differences of mitochondrial cytochrome c oxidase subunit I (mtCOI) gene observed between two populations of H. ulsana from different regions (Ulsan and Jeju Island) and between H. ulsana and H. urashima (Japan) were 1.1 % and 32.4 %, respectively. Two genetically-close populations differed in the setae on pleopod 3, the proximal setae on the maxilliped coxa, and the ventral setae on pereopods 2-3, which showed that geographical distance affected the morphological divergence. In addition, a comprehensive comparison with previous records of Hexapleomera was conducted and close examinations on the appendages, known to have morphological variations between the individuals of one species and/or between different genders, were carried out based on new species and discussed herein.
Project description:<h4>Background</h4>The beating or fanning movements of three pairs of maxilliped flagella in crabs and crayfish modify exhalent gill currents while drawing water over chemoreceptors on the head. They play an integral part both in signalling by distributing urine odours, and in active chemosensation.<h4>Results</h4>The rhythmical maxilliped movements start with maxilliped 3 followed after a delay of 15 to 20 ms in shore crabs by maxilliped 2 and then maxilliped 1, at a frequency of 18 to 20 Hz in crabs and 10 to 13 Hz in signal crayfish. The contraction of a single abductor muscle controls the power stroke (abduction) of each flagellum, which is accompanied by flaring of feather-like setae which increase its surface area. No muscle can bring about the return stroke (adduction). Release of an isolated flagellum from an imposed abduction is followed by a rapid recoil to its resting adducted position. The relationship between the extent of abduction and the angular velocity of the return stroke indicates the operation of a spring. Blue fluorescence under UV light, and its dependence on the pH of the bathing medium, indicates that resilin is present at the joint between an exopodite and flagellum, at the annuli of a flagellum and at the base of the setae.<h4>Conclusion</h4>Resilin is progressively bent as a flagellum is abducted and resumes its natural shape when the joint recoils. Other distortions of the exopodites may also contribute to this spring-like action. The joint is therefore controlled by a single abductor muscle operating against a spring in which the elastic properties of resilin play a key role.
Project description:The oceanographic conditions of the Pacific Ocean are largely modified by El Niño (EN), affecting several ecological processes. Parasites and other marine organisms respond to environmental variation, but the influence of the EN cycle on the seasonal variation of parasitic copepods has not been yet evaluated. We analysed the relation between infection parameters (prevalence and mean intensity) of the widespread parasitic copepods Caligus bonito and Charopinopsis quaternia in the dolphinfish Coryphaena hippurus and oceanography during the strong 2015-16 EN. Fish were collected from capture fisheries on the Ecuadorian coast (Tropical Eastern Pacific) over a 2-year period. Variations of sea surface temperature (SST), salinity, chlorophyll a (Chl-a), Oceanic Niño Index (ONI), total host length (TL) and monthly infection parameters of both copepod species were analysed using time series and cross-correlations. We used the generalised additive models for determine the relationship between environmental variables and infection parameters. The total body length of the ovigerous females and the length of the eggs of C. bonito were measured in both periods. Infection parameters of both C. bonito and Ch. quaternia showed seasonal and annual patterns associated with the variation of environmental variables examined (SST, salinity, Chl-a and ONI 1+2). Infection parameters of both copepod species were significantly correlated with ONI 1+2, SST, TL and Chl-a throughout the GAMLSS model, and the explained deviance contribution ranged from 16%-36%. Our results suggest than an anomaly higher than +0.5°C triggers a risen in infection parameters of both parasitic copepods. This risen could be related to increases in egg length, female numbers and the total length of the ovigerous females in EN period. This study provides the first evidence showing that tropical parasitic copepods are sensitive to the influence of EN event, especially from SST variations. The observed behaviour of parasitic copepods likely affects the host populations and structure of the marine ecosystem at different scales.