New records for Dinemoura ferox (Copepoda: Siphonostomatoida: Pandaridae) from Pacific sleeper sharks captured in waters off eastern Taiwan

Four of the 27 Pacific sleeper sharks (Somniosus pacificus Bigelow and Schroeder) captured in the western North Pacific Ocean off eastern Taiwan between 19 March and 18 May 2002 hosted the parasitic copepod Dinemoura ferox (Kr?yer, 1838) on their body surface including the fins. This report documents a new host record as well as a new ocean record for D. ferox, which until now has only been reported from the benthopelagic sharks, Somniosus microcephalus (Bloch and Schneider) and Centrophorus squamosus (Bonnaterre), occurring in the north Atlantic Ocean off Greenland and Iceland.     

Revision of the monogenean subfamily Neothoracocotylinae Lebedev, 1969 (Polyopisthocotylea: Thoracocotylidae)

Members of the subfamily Neothoracocotylinae are gastrocotylinean monogeneans on the gills of scombrid fishes of the genera Scomberomorus and Acanthocybium, and reportedly of a coryphaenid fish belonging to the genus Coryphaena. We revise the diagnosis of the subfamily and its two genera and accept only two species as valid. Neothoracocotyle acanthocybii (Meserve, 1938) Hargis, 1956 is known from Acanthocybium solandri throughout the Pacific Ocean and in the western Atlantic. N. coryphaenae (Yamaguti, 1938) Hargis, 1956, known only from a single specimen and described from Coryphaena hippurus in Japan, is synonymised with N. acanthocybii. The sole member of Scomberocotyle, S. scomberomori (Koratha, 1955) Hargis, 1956, infects five species of Scomberomorus in the eastern Pacific Ocean and the western and eastern Atlantic. We record this worm from several new hosts and/or localities, including S. sierra and S. concolor in the eastern Pacific (Mexico to Colombia), S. maculatus and S. cavalla in the western Atlantic (USA to Brazil), and S. tritor in the eastern Atlantic (Sierra Leone to Nigeria).     

Tracing the introduction history of the invasive swimming crab <Emphasis Type="Italic">Charybdis hellerii</Emphasis> (A. Milne-Edwards, 1867) in the Western Atlantic: evidences of high genetic diversity and multiple introductions

The swimming crab Charybdis hellerii is an invader with global distribution in warm waters. Native to the Indo-Pacific, this species invaded the eastern Mediterranean Sea after the Suez Canal opening. In 1987, it was first reported in the Western Atlantic, probably transported via ballast water of ships. Since then, it has been registered from many localities along the American coast from the USA to southern Brazil where it has rapidly established reproducing populations. Our main aim was to investigate the introduction history of this species along the American coast, using a phylogeographic approach. Additionally, we attempted to clarify the identity of this invasive species by molecular analyses and morphological assessment in order to provide a basis for our main investigation. C. hellerii was confirmed as a single species, but both cytochrome c oxidase subunit I and 16S rDNA revealed a genetic structure, splitting the potential source populations of American introductions into two groups: “western Indian Ocean and Mediterranean Sea” (WIO + MS) versus “eastern Indian + western Pacific oceans” (EIO + WPO). Most specimens from America clustered with the former group, supporting the hypothesis that the Mediterranean Sea represented the main source of Western Atlantic populations. However, the clustering of animals from southern Brazil with the latter group indicates that introductions from the eastern Indian or Pacific oceans must also have occurred. The existence of a third group, found exclusively within the American range and genetically related to EIO + WPO, also indicates an independent introduction from an unsampled locality from the native range. The haplotype and nucleotide diversities of American localities were comparable to those of source populations, contradicting a founder effect prediction. This finding might be related to the high propagule pressure associated with introductions via ballast water and the occurrence of multiple introductions from genetic distinct sources. The direct comparison of the haplotype numbers suggested no genetic bottleneck during introduction from the Mediterranean Sea, but a bottleneck might have occurred during introductions from the eastern Indian or Pacific oceans.     

The introduction to Japan of the Titan barnacle,Megabalanus coccopoma (Darwin, 1854) (Cirripedia: Balanomorpha) and the role of shipping in its translocation

The Titan Acorn barnacle, Megabalanus coccopoma, a native of the tropical eastern Pacific, has become established in the western Atlantic (Brazil and the northern Gulf of Mexico to the Carolinas), northwestern Europe and the western Indian Ocean (Mauritius), and therefore its dispersal capabilities are well known. This study reports its introduction to Japan and confirms its occurrence in Australia. In an attempt to determine the source of this introduction, phylogeographic techniques, involving cytochrome c oxidase I sequences of various widely separate populations of M. rosa and M. volcano, were utilized. No significant genetic differentiation or haplotype patterns between widely separated populations of each of the three species were found. Lack of such differentiation indicates recent geographical isolation and thus negates a null hypothesis predicting that the occurrence of one of more of these species in Australia was natural.     

Oceanographic barriers,divergence, and admixture: Phylogeography and taxonomy of two putative subspecies of short‐finned pilot whale

Genomic phylogeography plays an important role in describing evolutionary processes and their geographic, ecological, or cultural drivers. These drivers are often poorly understood in marine environments, which have fewer obvious barriers to mixing than terrestrial environments. Taxonomic uncertainty of some taxa (e.g., cetaceans), due to the difficulty in obtaining morphological data, can hamper our understanding of these processes. One such taxon, the short‐finned pilot whale, is recognized as a single global species but includes at least two distinct morphological forms described from stranding and drive hunting in Japan, the “Naisa” and “Shiho” forms. Using samples (n = 735) collected throughout their global range, we examine phylogeographic patterns of divergence by comparing mitogenomes and nuclear SNP loci. Our results suggest three types within the species: an Atlantic Ocean type, a western/central Pacific and Indian Ocean (Naisa) type, and an eastern Pacific Ocean and northern Japan (Shiho) type. mtDNA control region differentiation indicates these three types form two subspecies, separated by the East Pacific Barrier: Shiho short‐finned pilot whale, in the eastern Pacific Ocean and northern Japan, and Naisa short‐finned pilot whale, throughout the remainder of the species' distribution. Our data further indicate two diverging populations within the Naisa subspecies, in the Atlantic Ocean and western/central Pacific and Indian Oceans, separated by the Benguela Barrier off South Africa. This study reveals a process of divergence and speciation within a globally‐distributed, mobile marine predator, and indicates the importance of the East Pacific Barrier to this evolutionary process.     

Worldwide phylogeography of the blacktip shark (Carcharhinus limbatus) inferred from mitochondrial DNA reveals isolation of western Atlantic populations coupled with recent Pacific dispersal

Although many coastal shark species have widespread distributions, the genetic relatedness of worldwide populations has been examined for few species. The blacktip shark, (Carcharhinus limbatus), inhabits tropical and subtropical coastal waters throughout the world. In this study, we examined the genetic relationships of blacktip shark populations (n = 364 sharks) throughout the majority of the species' range using the entire mitochondrial control region (1067-1070 nucleotides). Two geographically distinct maternal lineages (western Atlantic, Gulf of Mexico, and Caribbean Sea clades, and eastern Atlantic, Indian, and Pacific Ocean clades) were identified and shallow population structure was detected throughout their geographic ranges. These findings indicate that a major population subdivision exists across the Atlantic Ocean, but not the Pacific Ocean. The historical dispersal of this widespread, coastal species may have been interrupted by the rise of the Isthmus of Panama. This scenario implies historical dispersal across the Pacific Ocean (supported by the recovery of the same common haplotype from the Philippines, Hawaii, and the Gulf of California reflecting recent/contemporary dispersal abilities) and an oceanic barrier to recent migration across the Atlantic. Genetic structure within the eastern Atlantic/Indo-Pacific (Phi(ST) = 0.612, P < 0.001) supports maternal philopatry throughout this area, expanding previous western Atlantic findings. Eastern Atlantic/Indo-Pacific C. limbatus control region haplotypes were paraphyletic to Carcharhinus tilstoni haplotypes in our maximum-parsimony analysis. The greater divergence of western Atlantic C. limbatus than C. tilstoni from eastern Atlantic/Indo-Pacific C. limbatus reflects the taxonomic uncertainty of western Atlantic C. limbatus.     

Population structure in the pan-oceanic wreckfish, Polyprion americanus (Teleostei: Polyprionidae), as indicated by mtDNA variation

The wreckfish Polyprion americanus , a large [>1 m total length ( L _T)] demersal teleost, is distributed globally in temperate waters, including both sides of the North and South Atlantic Oceans, the Mediterranean, the western South Pacific, and the southern Indian Ocean. Wreckfish spawn off the south-eastern U.S. on an area of the Blake Plateau (the Charleston Bump) characterized by an extensive ridge having approximately 100 m relief, in 450–600 m depths. Juvenile wreckfish (<60 cm L _T) are pelagic and, in the North Atlantic, are not reported from the Blake Plateau fishing area, but occur in by-catch and fishery landings in the eastern Atlantic. Analysis of nine restriction fragment length profiles from a PCR-amplified fragment (∼1.5 kb) of the ND1 mitochondrial gene indicated no stock separation between eastern North Atlantic (Azores, Majorca, Madeira), and western North Atlantic (Blake Plateau) wreckfish. Restriction site differences separate western South Atlantic wreckfish from the North Atlantic; however, South Atlantic wreckfish share restriction-site similarities with western Pacific wreckfish that are not shared with North Atlantic wreckfish. North Atlantic circulation provides a mechanism for a long-lived pelagic stage to be dispersed from Blake Plateau spawning grounds to the eastern North Atlantic. Global circulation patterns may explain both the dispersal of mtDNA haplotypes and the disjunct distribution of wreckfish body lengths in a temperate, deep-water vagile species with an extended pelagic juvenile stage such as wreckfish.     

Revision of the monogenean subfamily Priceinae Chauhan, 1953 (Polyopisthocotylea: Thoracocotylidae)

Members of the subfamily Priceinae are gastrocotylinean monogeneans of the gills of scombrid fishes of the genus Scomberomorus (and perhaps the genera Acanthocybium, Rastrelliger and Katsuwonus) from warm to warm-temperate seas of the world. We revise the diagnosis of the subfamily and regard the Mexicotylinae Lebedev, 1984 as a synonym. Two monotypic genera are accepted as valid. Pricea multae Chauhan, 1945 is recorded from seven species of Scomberomorus from the Indo-west Pacific, from off eastern South Africa north to the Persian Gulf and as far east as Fiji. New synonyms we recognise include P. minimae Chauhan, 1945 (described from India, reportedly on Katsuwonus pelamis), P. solandri Gupta & Chanana, 1977 (a single specimen was described from India, reportedly on Acanthocybium solandri) and P. microcotylae Chauhan, 1945 (also described from India, reportedly on Rastrelliger kanagurta). Mexicotyle mexicana (Meserve, 1938) Lebedev, 1984 is recorded on four species of Scomberomorus from the western Atlantic Ocean (United States to Brazil), two in the eastern Pacific (California to Peru) and one from the eastern Atlantic (Ghana).     

Species-level phylogeography and evolutionary history of the hyperdiverse marine gastropod genus Conus

Phylogenetic and paleontological analyses are combined to reveal patterns of species origination and divergence and to define the significance of potential and actual barriers to dispersal in Conus, a species-rich genus of predatory gastropods distributed throughout the world's tropical oceans. Species-level phylogenetic hypotheses are based on nucleotide sequences from the nuclear calmodulin and mitochondrial 16S rRNA genes of 138 Conus species from the Indo-Pacific, eastern Pacific, and Atlantic Ocean regions. Results indicate that extant species descend from two major lineages that diverged at least 33 mya. Their geographic distributions suggest that one clade originated in the Indo-Pacific and the other in the eastern Pacific + western Atlantic. Impediments to dispersal between the western Atlantic and Indian Oceans and the central and eastern Pacific Ocean may have promoted this early separation of Indo-Pacific and eastern Pacific + western Atlantic lineages of Conus. However, because both clades contain both Indo-Pacific and eastern Pacific + western Atlantic species, migrations must have occurred between these regions; at least four migration events took place between regions at different times. In at least three cases, incursions between regions appear to have crossed the East Pacific Barrier. The paleontological record illustrates that distinct sets of Conus species inhabited the Indo-Pacific, eastern Pacific + western Atlantic, and eastern Atlantic + former Tethys Realm in the Tertiary, as is the case today. The ranges of <1% of fossil species (N=841) spanned more than one of these regions throughout the evolutionary history of this group.     

REPORT OF A NEW INVASIVE ALGA IN THE ATLANTIC UNITED STATES: “HETEROSIPHONIA” JAPONICA IN RHODE ISLAND1

Recent collections of tetrasporangiate “Heterosiphonia” japonica Yendo from Watch Hill to Point Judith, Rhode Island, represent the first report of this nonnative alga in the western Atlantic. Native to the Pacific Ocean, this species was unintentionally introduced into European waters by 1984 and has subsequently invaded the eastern Atlantic Ocean widely from France to Norway and south into the Mediterranean Sea. Thus far, all western Atlantic collections of this species are confined to the outer coast of Rhode Island, and at present are not found in Narragansett Bay or in Long Island Sound along the Connecticut coast. Molecular and morphological studies confirm the identity of this newly introduced invasive species.