Study of the marine planktonic dinoflagellate Ceratium divaricatum (Dinophyceae), a confused and considerably variable species

The species Ceratium divaricatum (Lemmermann) Kofoid has largely been subject to misidentification and taxonomic confusion. The history of the species is complex: originally illustrated by Bergh (1881) as Ceratium tripos var., for which Lemmermann (1899) gave it the name Ceratium tripos var. divaricatum; the name Ceratium divaricatum was used by Kofoid (1908) with no specification of authors or references. It shows a high degree of morphological variation and development of autotomy of the apical and antapical horns. This great morphological variation has led to misidentifications in routine examinations of phytoplankton materials, and several names have been used for this species, including Ceratium dens, Ceratium porrectum and Ceratium tripos var. ponticum, as well as Ceratium balechii, a proposed new species for intermediate forms. Here, the species is redescribed, on the basis of material from Mexican Pacific coasts. Morphological and ecologic differences exist among this species and other closely related ones. Distribution of C. divaricatum is wider than previously documented (mainly because of previous misidentifications): the North Pacific Ocean, from British Columbia in Canada to temperate or subtropical waters of Mexico, and then is interrupted to reappear again in coasts of Peru and Chile, and also in coasts of the Benguela area, the South‐west Atlantic Ocean. In tropical and equatorial areas of the Pacific Ocean, a more delicate form occurs, herein proposed as a variety of this species: Ceratium divaricatum var. balechii. C. divaricatum and var. balechii may be relatively abundant, even producing non‐toxic red tides, in various spots along coasts of the Pacific Ocean (Canada to Mexico). It appears to be a neritic form, with high sensibility to changes in water temperature, and presumably associated to upwelling areas.     

Is the tiger shark Galeocerdo cuvier a coastal species? Expanding its distribution range in the Atlantic Ocean using at‐sea observer data

The occurrence of tiger shark Galeocerdo cuvier in the Atlantic Ocean was assessed using at‐sea observer data from multiple pelagic longline fisheries. Geographic positions of 2764 G. cuvier recorded between 1992 and 2013 and covering a wide area of the Atlantic Ocean were compared with the currently accepted distribution ranges of the species. Most records fell outside those ranges in both the Southern and Northern Hemispheres, which strongly suggests that the distribution range of G. cuvier in the open ocean is considerably larger than previously described     

Blitzkrieg in a Marine Invasion: Caulerpa racemosa var. cylindracea (Bryopsidales, Chlorophyta) Reaches the Canary Islands (North-East Atlantic)

On the basis of morphological and genetic studies (rDNA ITS1, 5.8S, ITS2, and a 18S rDNA intron), we confirm here that Caulerpa racemosa var. cylindracea (Sonder) Verlaque, Huisman et Boudouresque, a southwestern Australian taxon recently introduced into the Mediterranean Sea also occurs in the Canary Islands. This is the first report of C. racemosa var. cylindracea in the Atlantic. It was observed for the first time in the Canary Archipelago in 1997–1998. The speed and regional scale of expansion (north Atlantic Ocean and the Mediterranean Sea) of this invasive species appear to be among the most dramatic ever recorded. The possible outcome of this introduction in the Atlantic is discussed.     

Grateloupia turuturu (Halymeniaceae,Rhodophyta) is the correct name of the non-native species in the Atlantic known as Grateloupia doryphora

Grateloupia doryphora (Montagne) Howe, originally described from Peru, has repeatedly been reported as an invasive species in Atlantic and Mediterranean waters. Various attempts to explain this species' route of introduction have been unsatisfactory. New evidence from comparative rbcL sequence analysis and morphology suggests that this adventive species in the NE and NW Atlantic corresponds with G. turuturu Yamada, originally described from Japan. This provenance follows a well-recognized trend of invasive marine organisms that have colonized the Atlantic Ocean and Mediterranean Sea from Pacific NE Asia.     

<Emphasis Type="Italic">Bathyraja leucomelanos</Emphasis>, a new species of softnose skate (Chondrichthyes: Arhynchobatidae) from New Caledonia

A new species of softnose skate (Arhynchobatidae) is described, based on a single adult male measuring 895 mm TL that was collected at a depth of 953–1,022 m on the Coriolis Bank off western New Caledonia in the southwestern Pacific Ocean. The specimen conforms to the genus Bathyraja in having the rostral cartilage continuous with the neurocranium and very slender and uncalcified over its length. Bathyraja leucomelanos sp. nov. differs from its congeners through a combination of the following characters: distinctive coloration of the disc with white dorsal and black ventral surfaces, dorsal surface of the disc entirely covered with dermal denticles, ventral surface naked, anterior portion of the anterior margin of the disc straight, snout long and very broad with orbit about 6.0 times in preorbital length, orbit 0.73 times interorbital width, mouth 6.8% TL, tail 0.88 times precloacal length, accessory terminal 2 cartilage of the clasper having an expanded disc-shaped tip, and alar thorn tip undulating. Molecular barcoding from the COI sequence reveals that this new species is genetically close to B. spinicauda from the North Atlantic Ocean.     

The Lepocreadiidae (Digenea) of fishes from the north-east Atlantic: review of the genusParalepidapedon Shimazu & Shimura, 1984, with a description ofP. williamsi n. sp.

A new species,Paralepidapedon williamsi, is described from the fishCottunculus microps and an unidentified fish of the suborder Cottoidei in the NE Atlantic Ocean. This species is the first member of the genus to be recognized in the Atlantic Ocean. Its general morphology is similar to that of the other members of the genus, but it is distinguished by its large eggs and the relatively few gland-cells associated with the external seminal vesicle. The genusParalepidapedon, which differs fromNeolepidapedon in the possession of a uroproct, is reviewed and a key to the species given. The genus is considered to include five species.     

Revision of genus Melamphaes (Melamphaidae): Part 4. Multi-raker species: M. ebelingi, M. occlusus sp. nova, and M. nikolayi sp. nova

In the fourth part of the revision of the genus Melamphaes (Melamphaidae) multi-raker species (20 and more rakers at the first gill arch, rarely 19??in M. ebelingi) with eight soft rays in the ventral fin are considered. In this species, temporal spine is absent, there are 15 rays in the pectoral fin, and there are 11 to 12 abdominal vertebrae. M. ebelingi inhabits tropical and subtropical waters of the Atlantic Ocean. A new catch of this rare species in the northeastern part of the ocean is reported. The new species M. occlusus is described from one specimen from the subtropical part of the southwestern part of the Indian Ocean. Still another new species, M. nikolayi, is described from one specimen from the northwestern part of the Pacific Ocean (subtropical waters). A table for identification of 15 multi-raker species of the genus Melamphaes is provided.     

Revision of the genus <Emphasis Type="Italic">Melamphaes</Emphasis> (Melamphaidae): Part 3. Multirakered species: <Emphasis Type="Italic">M. suborbitalis,M. parini</Emphasis>, and <Emphasis Type="Italic">M. acanthomus</Emphasis>

In the third part of the revision of the genus Melamphaes Melamphaidae (Melamphaidae), we examine multirakered species (20 and more rakers at the first gill arch) with seven soft rays in the ventral fin that have a posttemporal (temporal) spine directed anteriorly-upwards, with 14–15 rays in the pectoral fin, and 11 (rarely 12) trunk vertebrae. M. suborbitalis inhabits the Atlantic Ocean (in the north up to 57°N, in the south, up to 40°S), the Indian Ocean (is known in its southwestern part), and the western part of the Pacific Ocean. There is no significant evidence on catches of this species in the eastern part of the Pacific Ocean. Apparently, M. suborbitalis is absent in the tropical waters of the oceans. Until recently, M. parini was known from the holotype caught in the Sea of Okhotsk. Two specimens of this rare species: from the central (the area of the Hawaiian Islands) and the northeastern part of the Pacific Ocean are reported. M. acanthomus is an endemic of the eastern part of the Pacific Ocean where it is known along the coasts of America from California to the northern coast of Chile (approximately between 33°N and 21°S).     

EST and Mitochondrial DNA Sequences Support a Distinct Pacific Form of Salmon Louse, <Emphasis Type="Italic">Lepeophtheirus salmonis</Emphasis>

Nuclear deoxyribonucleic acid sequences from approximately 15,000 salmon louse expressed sequence tags (ESTs), the complete mitochondrial genome (16,148bp) of salmon louse, and 16S ribosomal ribonucleic acid (rRNA) and cytochrome oxidase subunit I (COI) genes from 68 salmon lice collected from Japan, Alaska, and western Canada support a Pacific lineage of Lepeophtheirus salmonis that is distinct from that occurring in the Atlantic Ocean. On average, nuclear genes are 3.2% different, the complete mitochondrial genome is 7.1% different, and 16S rRNA and COI genes are 4.2% and 6.1% different, respectively. Reduced genetic diversity within the Pacific form of L. salmonis is consistent with an introduction into the Pacific from the Atlantic Ocean. The level of divergence is consistent with the hypothesis that the Pacific form of L. salmonis coevolved with Pacific salmon (Onchorhynchus spp.) and the Atlantic form coevolved with Atlantic salmonids (Salmo spp.) independently for the last 2.5–11 million years. The level of genetic divergence coincides with the opportunity for migration of fish between the Atlantic and Pacific Ocean basins via the Arctic Ocean with the opening of the Bering Strait, approximately 5 million years ago. The genetic differences may help explain apparent differences in pathogenicity and environmental sensitivity documented for the Atlantic and Pacific forms of L. salmonis. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

A new species of parasitic copepod,Shiinoa bakeri (Shiinoidae), with a new host record for Shiinoa elagata Cressey

Summary A new species of Shiinoa parasitic on the nasal lamellae of Indian Ocean and western Atlantic lutjanid fishes is described. A new record of Shiinoa elagata, originally described from Pacific Elagatus bipinnulatus, is reported from western Atlantic Sphyraena barracuda from Belize. The new species described herein brings the total number of Shiinoa species described to four. The family Shiinoidae is redefined.     

Some new and little known phytoplankton forms from the West Indian Ocean

New records of Pterosperma spp., Pachysphaera spp. and Meringosphaera spp. are made from light microscope studies of cleared millipore filter disc samples from the West Indian Ocean. One new species and one new form of the genus Pterosperma are described from these samples. An occurrence of the newly described species, Pterosperma parvareopunctatum, is also recorded from the gut contents of an ostracod from a deep haul in the East Atlantic Ocean.     

Meristic and morphometric variation in the lancet fish,Alepisaurus, with notes on the distribution of A. ferox and A. brevirostris

Abstract

Meristies and morphometries are reported for 81 specimens of Alepisaurus ferox and 31 of A. brevirostris, mostly from the Pacific Ocean. The holotype and topotype of A. ferox and two paratypes of A. brevirostris, all from the Atlantic Ocean, were also examined. For specimens longer than aJoout 500 mm SL, ferox is distinguishable from brevirostris by its relatively longer head and snout. In ferox the dorsal fin origin is a1bove or behind the hind margin of the operculum; in brevirostris it is in front. Paoific Ocean ferox have significantly fewer dorsal fin rays (mean 36.6) than Atlantic (40.5) and Indian Ocean (40.8) examples. In the Pacific, ferox can be distinguished from brevirostris by its fewer dorsal rays, but in the Atlantic and the Indian Ocean there is considerable overlap in dorsal ray counts. A. ferox is found world-wide, whereas brevirostris is not known from the North Pacific. The northernmost record of brevirostris in the Pacific is from 14°47′S.     

Panbiogeographical analysis of distribution patterns in hagfishes (Craniata: Myxinidae)

Aim To analyse the worldwide distribution patterns of hagfishes using panbiogeographical track analysis, and to attempt to correlate these patterns with the tectonic history of the ocean basins. Location Atlantic and Pacific oceans. Method The distributions of 47 out of 70 species of hagfish (in the genera Eptatretus, Myxine, Nemamyxine, Neomyxine, and Paramyxine) were studied by the panbiogeographical method of track analysis. The analysis was performed using distributional data obtained from the collections included in the Ocean Biogeographic Information System (OBIS, http://www.iobis.org ) and FishBase ( http://www.fishbase.org ), with additional records from the literature. Individual tracks were obtained for each species by plotting localities and connecting them by minimum‐spanning trees. Generalized tracks were determined from the spatial overlap between individual tracks. Results Six generalized tracks were found: in the Gulf of Mexico, Caribbean Sea, South‐eastern Atlantic, Western Pacific, North‐eastern Pacific and South‐eastern Pacific. Main conclusions The distribution patterns of myxinids are marked by a high degree of endemism and vicariance, and are correlated with the tectonic features involved in many of the events that led to the development of oceanic basins. The main massing of the group is around the Pacific Basin. In the Atlantic Ocean, the distribution of Myxine glutinosa seems to correspond to a classic trans‐oceanic track and vicariance resulting from the opening of the Atlantic Ocean during the Cretaceous. In the Pacific Ocean, the distribution of the Eptatretus and Paramyxine species is clearly associated with the margins of the Pacific tectonic plate. The generalized tracks of hagfishes are shared by several other groups of marine organisms, including many from shallow tropical waters, implying a common history for this marine biota. Overall, vicariance is a major feature of hagfish distribution, suggesting vicariant differentiation of widespread ancestors as a result of sea‐floor spreading between continents in connection with ocean formation.     

Plectorhinchus macrolepis (Actinopterygii: Haemulidae) in the western Atlantic Ocean

Morphometric measurements, meristic counts and DNA barcoding identified the presence of a biglip grunt Plectorhinchus macrolepis in the western Atlantic Ocean. As the species is endemic to the tropical eastern Atlantic Ocean and has not previously been reported in the western Atlantic Ocean, we discuss the possible means by which it might have dispersed to the western Atlantic Ocean. Even though this species is not considered established in Paranaguá Bay, we advocate monitoring of possible new individuals and other exotic fish species.     

A new species of Ainudrilus (Tubificidae) from South Georgia,and other subantarctic freshwater oligochaetes

The freshwater oligochaetes of the subantarctic islands are reviewed and new records are given. Ainudrilus dartnalli sp.n. (subfamily Rhyacodrilinae) is described from freshwater sites on South Georgia (South Atlantic Ocean). It differs from the closely related, southwest Australian, A. nharna Pinder & Brinkhurst, by its longer clitellum, the longer upper teeth of its ventral somatic chaetae, its straighter and fewer penial chaetae, and by the proportions of its spermathecae. Range extensions are given for two widespread naidids, Nais variabilis Piguet and N. communis Piguet, from the Falkland Islands (S. Atlantic). Moreover, new material of N. elinguis Müller is recorded from Macquarie Island (Southern Ocean, SW of New Zealand).