Halosauropsis Research Articles

Identification keys to halosaurs and notacanthids (Notacanthiformes, Elopomorpha) in the subarctic Atlantic Ocean including three new distributional records and multiple molecular OTUs of Notacanthus cf. chemnitzii

As part of an ongoing effort to monitor the fish diversity in Greenland waters using morphological and molecular taxonomy, and construct pragmatic identification keys, we here update distributions of all known halosaurs (Halosauridae) and notacanthids (Notacanthidae) in the subarctic Atlantic Ocean. New distributions are included for Aldrovandia oleosa, Halosauropsis macrochir, and Notacanthus bonaparte, all caught once in the Denmark Strait off SE Greenland. We also present the first observation of luminous tissues in halosaurs. Photo, illustrative and text identification keys are included for pragmatic identification corroborated by molecular barcoding data, produced as part of the Greenland Fishes Barcoding Project (GLF) introduced in this study. Barcoding data revealed five operational taxonomic units (OTUs) of Notacanthus cf. chemnitzii present, including three distinct haplotypes observed off SE Greenland alone, within this species complex currently described as one circumglobal species.

DNA Barcoding and Genetic Structure Analysis of Deep-Sea Notacanthiform Fishes

Event Abstract Back to Event DNA Barcoding and Genetic Structure Analysis of Deep-Sea Notacanthiform Fishes David Barros-García1*, Rafael Bañon1, Juan Carlos Arronte2, Lourdes Fernandez3, Ramón García3 and Alejandro De Carlos1 1 University of Vigo, Spain 2 Spanish Institute of Oceanography, Spain 3 Spanish Institute of Oceanography, Spain Notacanthiformes Goodrich, 1909 is an order of deep-sea, benthopelagic or benthic fishes distributed from the continental slope to the abyssal plain, at a depth of between 125 and 4,900 m, but mostly occurring at depths of 450-2,500 m. They are characterized by an eel-like body, a snout projecting conspicuously beyond the mouth, large connective tissue nodules inserted between the pterygoid arch and maxilla and pelvic fin webs joined in the ventral midline. Fishes from this order were classified applying DNA barcoding. Cytochrome c oxidase subunit I (COI) sequences belonging to new North Atlantic specimens and already deposited BOLD public records were used. The specimens from the two families of the order, Halosauridae (halosaurs) and Notacanthidae (spiny eels), formed separated monophyletic clades in neighbor-joining trees and the sequences clustered as coherent species. Nine out of 16 species of Halosauridae and 9 out of 10 species of Notacanthidae were represented including 166 sequences of which 96% were successfully identified. The DNA barcode of the rare species Lipogenys gillii was obtained for the first time ever. The DNA barcode was further tested by exploring the genetic structure and historical demography of four species of notacanthiforms from five sample locations of the North Atlantic and South West Pacific. Neutrality tests, mismatch distribution and haplotype networks analyses pointed to a past bottleneck episode followed by a fast demographic expansion for all the samples. The genetic structure of the abyssal halosaur Halosauropsis macrochir showed no significant differences between the North Atlantic and South West Pacific samples. DNA barcoding was successful in validating field identifications and assigning species names to sequences of notacanthiforms worldwide. These results constitute a first example of high connectivity and gene flow in this group of deep-sea fish species. The historical demography suggests population variations that may be due to past glaciation events. References Barros-García, D., Bañón, R., Arronte, J. C., Fernández-Peralta, L., García, R., & de Carlos, A. (2015). DNA barcoding of deep-water notacanthiform fishes (Teleostei, Elopomorpha). Zoologica Scripta. doi:10.1111/zsc.12154 Keywords: DNA barcoding, fish, Population Genetics, systematics, Evolution, Molecular Conference: XV European Congress of Ichthyology, Porto, Portugal, 7 Sep - 11 Sep, 2015. Presentation Type: Oral Presentation Topic: Phylogeny, Systematics and Genetics Citation: Barros-García D, Bañon R, Arronte J, Fernandez L, García R and De Carlos A (2015). DNA Barcoding and Genetic Structure Analysis of Deep-Sea Notacanthiform Fishes. Front. Mar. Sci. Conference Abstract: XV European Congress of Ichthyology. doi: 10.3389/conf.FMARS.2015.03.00179 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Nov 2015; Published Online: 01 Dec 2015. * Correspondence: Mr. David Barros-García, University of Vigo, Vigo, Spain, Davbarros@uvigo.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract Supplemental Data The Authors in Frontiers David Barros-García Rafael Bañon Juan Carlos Arronte Lourdes Fernandez Ramón García Alejandro De Carlos Google David Barros-García Rafael Bañon Juan Carlos Arronte Lourdes Fernandez Ramón García Alejandro De Carlos Google Scholar David Barros-García Rafael Bañon Juan Carlos Arronte Lourdes Fernandez Ramón García Alejandro De Carlos PubMed David Barros-García Rafael Bañon Juan Carlos Arronte Lourdes Fernandez Ramón García Alejandro De Carlos Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Bathyal demersal fishes of Charlie Gibbs Fracture Zone region (49–54°N) of the Mid-Atlantic Ridge, I: Results from trawl surveys

Demersal fishes were sampled by single-warp otter trawl (OTSB) at three sites on the Mid-Atlantic Ridge (MAR), to the northeast (NE), northwest (NW) and southeast (SE) of the Charlie–Gibbs Fracture Zone at approximately 2500m depth. The mean abundance was 4109fishkm−2 (SD 3714) and biomass 897.1kgkm−2 (SD 842.9) compared with 1996fishkm−2 (SD 1497) and 721.2kgkm−2 (SD 387) at the same depth on the Porcupine Seabight (PSB) segment of the NE Atlantic Ocean margin from previous studies. There was no significant difference in biomass or abundance between the three sites on the MAR, nor in comparison with the ocean margin. A total of fish 22 species were recorded at the three MAR sites with evidence of highest species richness at the SE site. No unique species were found on the ridge; but there were differences in species composition between the PSB and the MAR. Coryphaenoides brevibarbis and Antimora rostrata were important at both the NE and NW trawl sites on the MAR whereas Halosauropsis macrochir was most important in the SE. We conclude that the MAR is an important habitat for species otherwise confined to narrow strips of appropriate depth around the North Atlantic Ocean margins. The MAR supports similar population densities to ocean margin settings but with differences in relative importance of different species between regions.

Bathyal demersal fishes of the Charlie-Gibbs Fracture Zone region (49°–54°N) of the Mid-Atlantic Ridge: III. Results from remotely operated vehicle (ROV) video transects

Demersal fish were assessed by remotely operated vehicle (ROV) video transects at sites to the NE, NW (54°N), SE and SW (49°N) of the Charlie-Gibbs Fracture Zone (CGFZ) at ca. 2500m depth on the Mid-Atlantic Ridge. At each site, three different slope categories (flat, 10° slope and >30° slope) were sampled with four transects, each surveying 2000m3 of suprabenthic water. This resulted in 12 high-definition video transects at every site, covering a total of 24,000m3 suprabenthic water. Six species were observed; which was fewer than in surveys using baited landers (19 species) and trawls (26 species) in the same area. Bathysaurus ferox, Halosauropsis macrochir, Antimora rostrata and Polyacanthonotus challengeri did not vary in density between sites, while Coryphaenoides brevibarbis and Coryphaenoides armatus were significantly more abundant at the northern sites; the latter supporting findings using baited landers. The halosaur H. macrochir was the only species affected by slope. The majority of observed fish showed no reaction to one or more of the stimuli produced by the ROV, however burst swimming was observed at least once in all species except B. ferox. The most abundant species, C. brevibarbis, was particularly affected by the presence of the ROV.

Bathyal demersal fishes of Charlie-Gibbs Fracture Zone region (49–54°N) of the Mid-Atlantic Ridge: II. Baited camera lander observations

Demersal fishes appearing at baited cameras at 2500m depth either side of the axis of the Northern Mid-Atlantic Ridge (MAR) at 54°N and 49°, north and south of the Charlie Gibbs fracture Zone respectively, showed significant differences in species composition between north and south. A total of 19 taxa were observed, with Hydrolagus affinis, Bathyraja richardsoni, Halosauropsis macrochir, Histobranchus bathybius, Synaphobranchus kaupii, Coryphaenoides armatus, Corphaenoides brevibarbis, Coryphaenoides mediterraneus/leptolepis, Antimora rostrata and Spectrunculus crassa occurring at all locations. The total species assemblage comprised 40% of species captured by trawl at the same locations indicating a high proportion of scavenging species on the MAR. The most abundant was C. armatus showing shorter arrival times and larger body size in the north, suggestive of higher population density and higher food availability. The next most abundant species A. rostrata however showed faster arrival in the south but larger size in the North. No differences could be discerned between stations at the same latitude east and west of MAR axis.

High variability in spatial and temporal size-based trophodynamics of deep-sea fishes from the Mid-Atlantic Ridge elucidated by stable isotopes

Demersal fish play an important role in the deep-sea ecosystem by acting as a link to mobile food in the water column, consuming benthic fauna, breaking down large food parcels and dispersing organic matter over large areas. Poor diet resolution from stomach content analysis often impairs the ability to assess differences in inter- and intra-population trophodynamics and therefore understand resource partitioning among deep-sea fishes. Antimora rostrata (predator–scavenger), Coryphaenoides armatus (predator–scavenger), Coryphaenoides brevibarbis (predator) and Halosauropsis macrochir (predator) were collected from 3 stations on the Mid-Atlantic Ridge (MAR) in 2007 and 2009 to investigate trophic ecology using δ13C and δ15N. Variability in lipid-normalised δ13C (δ13Cn) and δ15N was explained by body length in all species but slope and significance of the isotope–length relationships varied both temporally and spatially. δ15N increases with length were observed in A. rostrata at all stations, C. brevibarbis and H. macrochir at one or more stations but were absent in C. armatus. δ13Cn increased with length in A. rostrata but the slope of δ13Cn–length relationships varied spatially and temporally in C. armatus and C. brevibarbis. The co-occurring δ13Cn and δ15N size-based trends in A. rostrata and H. macrochir suggested that size-based trends were a result of increasing trophic position. In C. armatus and C. brevibarbis the isotope-length trends were difficult to distinguish among trophic position increases, shifts in resource use i.e. benthic to pelagic or internal physiology. However, the overall strength, direction and significance of isotope-length trends varied temporally and spatially which suggested varying degrees of overlap in trophic ecology and feeding plasticity among these species.

Haematozoans from deep water fishes trawled off the Cape Verde Islands and over the Porcupine Seabight, with a revision of species within the genus Desseria (Adeleorina: Haemogregarinidae)

Archived blood smears from 32 of 113 fishes in 18 families and 12 orders, trawled from deep North Atlantic waters off the Cape Verde Islands in 1999 and over the Porcupine Seabight in 2001 were found to harbour haematozoans. These included four species of haemogregarines (Adeleorina, Haemogregarinidae) and a species of trypanosome (Trypanosomatina, Trypanosomatidae) located in Porcupine Seabight fishes. Also present were Haemohormidium-like structures of uncertain status found in samples from this location and from the Cape Verde Islands. Although material was limited, two of the haemogregarines were provisionally named Desseria harriottae sp. n. from Harriotta raleighana Goode et Bean (Chimaeriformes, Rhinochimaeridae), and Haemogregarina bathysauri sp. n. from Bathysaurus ferox Günther (Aulopiformes, Bathysauridae). The two remaining haemogregarines were identified as Desseria marshalllairdi (Khan, Threlfall et Whitty, 1992) from Halosauropsis macrochir (Günther) (Notacanthiformes, Halosauridae), and Haemogregarina michaeljohnstoni (Davies et Merrett, 2000) from Cataetyx laticeps Koefoed (Ophidiformes, Bythitidae). The name H. michaeljohnstoni was proposed to replace Haemogregarinajohnstoni Davies et Merrett, 2000 from C. laticeps and to avoid confusion with Hepatozoon johnstoni (Mackerras, 1961) Smith, 1996 from varanid lizards, originally named Haemogregarina johnstoni Mackerras, 1961. The trypanosome formed a mixed parasitaemia with D. harriottae in H. raleighana and was provisionally named Trypanosoma harriottae sp. n. No blood parasites had been described previously from cartilaginous fishes of the Holocephali, making the finds in H. raleighana unique. Haemohormidium-like structures were located in erythrocytes in one fish, Coryphaenoides armatus (Hector), among the Cape Verde Islands samples and in 12 species of fishes from the Porcupine Seabight; all these hosts were bony fishes. Finally, the haemogregarine species listed in the genus Desseria Siddall, 1995 were reassessed. Of the original list of 41 species, 30 were retained and 5 species added, including D. harriottae, so that the genus now contains 35 species.

Distribution, Population Biology, and Trophic Ecology of the Deepwater Demersal Fish Halosauropsis macrochir (Pisces: Halosauridae) on the Mid-Atlantic Ridge

Halosauropsis macrochir ranked amongst the most abundant and widespread demersal fishes on the mid-Atlantic Ridge of the North Atlantic (Iceland-Azores) with greatest abundance at 1700–3500 m. All sizes, ranging from 10–76 cm total length, occurred in the area without any apparent spatial pattern or depth trend. Using otolith sections displaying growth increments assumed to represent annuli, the age range recorded was 2–36 years, but most individuals were <20 years. Length and weight at age data were used to fit growth models. No differences between sexes in length and weight at age were observed. The majority of samples had a surplus of males. Diet analysis showed that H. macrochir feeds on Crustacea, Teleostei, Polychaeta, and Cephalopoda, but few prey could be identified to lower taxonomical levels. The mid-Atlantic Ridge constitutes a major portion of the North Atlantic living space of the abyssal halosaur where it completes its full life cycle, primarily as an actively foraging euryophagous micronekton/epibenthos and infauna feeder, becoming a partial piscivore with increasing size.

Osteology of Halosauridae (Notacanthiformes)

With reference to three species (Halosaurus pectoralis (McCulloch, 1926), Halosauropsis macro-chir (Gunther, 1878), and Aldrovandia phalacra (Vaillant, 1888)), specific features of skeleton structure in all three genera of Halosauridae fish are described. It is recommended to use the obtained results for the specification of classification of these fish.

Small-scale distribution of deep-sea demersal nekton and other megafauna in the Charlie-Gibbs Fracture Zone of the Mid-Atlantic Ridge

Abstract Videotapes from manned submersibles diving in the area of the Charlie-Gibbs Fracture Zone of the Mid-Atlantic Ridge were used to investigate the distribution of fishes, large crustaceans, epifaunal and sessile organisms, and environmental features along a series of transects. Submersibles MIR 1 and MIR 2 conducted paired dives in an area of mixed sediment and rock (beginning depth ca. 3000 m) and on a large pocket of abyssal-like sediments (depth ca. 4000 m). In the shallower area, the submersibles passed over extremely heterogeneous terrain with a diversity of nekton, epifaunal forms and sessile forms. In the first pair of dives, MIR 1 rose along the Mid-Atlantic Ridge from 3000 to 1700 m, while MIR 2 remained near the 3000 m isobath. Nekton seen in these relatively shallow dives included large and small macrourids (genus Coryphaenoides ), shrimp (infraorder Penaeidea), Halosauropsis macrochir , Aldrovandia sp., Antimora rostrata , and alepocephalids. The last two were more characteristic of the upper areas of the slope reached by MIR 1, as it rose along the Mid-Atlantic Ridge to depths less than 3000 m. Distributions of some forms seemed associated with depth and/or the presence of hard substrate. Sessile organisms such as sponges and large cnidaria were more likely to be found in rocky areas. The second pair of dives occurred in an abyssal area and the submersibles passed over sediment-covered plains, with little relief and many fewer countable organisms and features. The most evident of these were holes, mounds, small cerianthid anemones, small macrourids and the holothurian Benthodytes sp. A few large macrourids and shrimp also were seen in these deeper dives, as well as squat lobsters ( Munidopsis sp.). Sponges and larger cnidaria were mostly associated with a few small areas of rocky substrate. Holes and mounds showed distributions suggesting large-scale patterning. Over all dives, most sessile and epifaunal forms showed clumped distributions. However, large holothurians and large nekton often had distributions not significantly different from random.

Fish parasites in the bathyal zone: The halosaur Halosauropsis macrochir (Günther, 1878) from the Mid-Atlantic Ridge

Abstract A total of 42 Halosauropsis macrochir from a single position on the Mid-Atlantic Ridge (MAR) were collected for studies on parasites and feeding ecology. A total of 9 different parasite species were found, with most of them belonging to the Digenea (4 species) and Nematoda (3). The host specific Degeneria halosauri , (Digenea) and Cystidicolidae indet. (Nematoda) were the predominant species, reaching a prevalence of 100.0% and 57.1% with intensities of infection of 1–12 and 1–10, respectively. Less host specific parasites such as Gonocerca phycidis (Digenea) and Tetraphyllidea indet. (Cestoda) occurred at low rates of infection. The parasite fauna of this bathyal fish can be described as predominantly adult and host specific, with larval and less host specific components. A total of 16 different food groups were identified, most of them of benthic origin or associated with the benthopelagial. The predominant prey organisms belonged to the Crustacea (e.g., Copepoda, Gammaridea, Amphipoda and Isopoda), which serve as main parasite vectors for H. macrochir . This deep-sea fish seems to follow a general pattern of fish parasites in the deep sea, with most isolated parasites belonging to the digeneans, nematodes and a cestode. The parasite composition is caused by the narrow depth range of the species and the restricted distribution of the fish family Halosauridae. The species richness was found to be lower than other demersal fish from the deep sea and shallow waters, however, higher than those from deep-sea fish living in the pelagial.

A NEW SPECIES OF COMEPHORONEMA (NEMATODA: CYSTIDICOLIDAE) FROM THE STOMACH OF THE ABYSSAL HALOSAUR HALOSAUROPSIS MACROCHIR (TELEOSTEI) FROM THE MID-ATLANTIC RIDGE

A new species of parasitic nematode Comephoronema macrochiri n. sp. (Cystidicolidae), is described from the stomach of the marine deep-sea fish Halosauropsis macrochir (abyssal halosaur) from the Mid-Atlantic Ridge (MAR). The new species, studied with both light and scanning electron microscopy, is characterized mainly by 6 pairs of preanal papillae, by which it principally differs from members of Ascarophis; the spicules are 297-375 microm and 99-120 microm long and fully developed eggs possess 2 long filaments on 1 pole. Rhabdochona beatriceinsleyae is transferred to Comephoronema as C. beatriceinsleyae (Holloway and Klewer, 1969) n. comb. Comephoronema macrochiri differs from all other congeners mainly in having eggs with filaments on 1 pole only, and from individual species by some additional features such as the number of preanal papillae, the shape of pseudolabial projections, and the body and organ measurements.

Structural variation in the inner ears of four deep‐sea elopomorph fishes

Deep-sea fishes have evolved in dark or dimly lit environments devoid of the visual cues available to shallow-water species. Because of the limited opportunity for visual scene analysis by deep-sea fishes, it is reasonable to hypothesize that the inner ears of at least some such species may have evolved structural adaptations to enhance hearing capabilities in lieu of vision. As an initial test of this hypothesis, scanning electron microscopy was used to examine the structure of the inner ears of four deep-sea elopomorph species inhabiting different depths: Synaphobranchus kaupii, Synaphobranchus bathybius, Polyacanthonotus challengeri, and Halosauropsis macrochir. The shape of the sensory epithelia and hair cell ciliary bundle orientation of the saccule, lagena, and utricle, the three otolithic organs associated with audition and vestibular function, are described. The saccules of all four species have a common, alternating ciliary bundle orientation pattern. In contrast, the lagena exhibits more interspecific diversity in shape and ciliary bundle orientation, suggesting that it has special adaptations in these species. The macula neglecta, a sensory epithelium of unknown function, is present in all four species.

Rod Outer Segment Renewal in the Retinae of Deep-sea Fish

Outer segment renewal involves the synthesis of disc material in the photoreceptor inner segments, the shedding of the tips of the photoreceptor outer segments, and their phagocytosis by the retinal pigment epithelial cells. It has been suggested that in the retinae of deep-sea fish no renewal of outer segments may take place. In order to assess outer segment renewal in deep-sea fish retinae we counted (i) periciliary vesicles in rod inner segments as a parameter for disc-synthesis activity and (ii) phagosomes in retinal pigment epithelial cells as a parameter of shedding and phagocytosis in 12 species of deep-sea fish with multibank or single bank retinae. We also measured the lengths of rod outer segments in order to evaluate the balance between synthesis and phagocytotic activity. In four of these species ( Synaphobranchus kaupi, Nematonurus armatus, Coryphaenoides guentheri and Halosauropsis macrochir) we further recorded size-related changes of these parameters and their relation to the position of a given rod within the banks in the retina. The number of periciliary vesicles was highest in inner segments of the most vitread bank and in the periphery of the retina. Phagosomes were most abundant in retinal pigment epithelial cells of the central retina. Long rod outer segments were most frequently recorded in the peripheral retina indicating that in this region new synthesis may outbalance shedding. Vitread rod outer segments were only slightly longer than sclerad ones. Larger animals had shorter rod outer segments than small ones. We present evidence that rod outer segment renewal takes place in the retina of all deep-sea fish. Vitread rods may be more active in this respect than sclerad ones. Copyright © 1996 Elsevier Science Ltd.

New plagioporines (Digenea: Opecoelidae) from deep-sea fishes of the North Atlantic Ocean

Three new species of digenean are described from demersal fishes taken in deep waters of the northwestern and northeastern Atlantic Ocean: Podocotyle schistotesticulata n. sp. from Antimora rostrata; P. harrisae n. sp. from Coryphaenoides (Lionurus) carapinus; and Gaevskajatrema halosauropsi n. sp. from Halosauropsis macrochir. The status of the nominal species of the genus Podocotyle Dujardin, 1845 is presented in annotated summary, along with a tabulation of the distinctive characteristics of recognised species of the genus. Gaevskajatrema Gibson & Bray, 1982 is discussed and its diagnosis amended.

Scavenging deep demersal fishes of the Porcupine Seabight, north-east Atlantic: observations by baited camera, trap and trawl

Demersal fishes on the continental rise and slope were sampled by trawl, baited trap and a baited camera. Seventy-one different species were trawled, but only 18 species approached baits. At rise soundings (4100 m to 2250 m) Coryphaenoides (Nematonurus) armatus was dominant at baits and comprised 41·5% of the trawl catch. On the slope (&lt;2250 m) Synaphobranchus kaupi was dominant at baits and comprised 32·7% of the trawl catch. At 1500–2501 m Antimora rostrata competed at baits and comprised 5–10% of trawl catches. At 1500–1650 m Centroscymnus coelolepis also consumed baits but was not captured by trawl. For C. (N.) armatus abundance was proportional to tarr2 (where tarr= arrival time), demonstrating that arrival time of the first fish at baits provides an estimate of population density. Maximum estimated abundance at 2897 m was 877 km-2, more than five times the abundance on the abyssal plain. Halosauropsis macrochir, Lepidion eques, Coryphaenoides guentheri, Gadiculus argenteus and Coryphaenoides rupestris were important in trawl samples but absent or rare at baits.