Winter migration of rockhopper penguins (Eudyptes c. chrysocome) breeding in the Southwest Atlantic: is utilisation of different foraging areas reflected in opposing population trends?

Rockhopper penguins (Eudyptes chrysocome) breeding on Staten Island, Argentina, were satellite tracked in 2002 and 2003 during the onset of their winter migration. After their moult, the dispersal of 24 birds was monitored for a mean period of 50.0±40.3 days. Birds travelled at a mean velocity of 3.1±1.1 km/h. The mean minimum distance travelled was 1,640±1,425 km; the maximum distance to the colony was generally less than 1,000 km, although one bird travelled more than 2,000 km from the colony. The penguins dispersed over an area totalling about 1.3 million km2, ranging from 50 to 62°S and from 49°W in the Atlantic to 92°W in the Pacific, and covering polar, sub-polar and temperate waters in oceanic regions as well as shelf waters. Despite the very wide dispersal, both temporally and spatially, two important wintering grounds for rockhopper penguins from Staten Island could be identified, both located over shelf regions: one extended from Staten Island to the north along the coast of Tierra del Fuego up to the Magellan Strait; the other was located over the Burdwood Bank, an isolated extension of the Patagonian Shelf to the south of the Falkland Islands. The Drake Passage also appeared to be an important area for wintering penguins, although dispersal was far more widely spread. Comparison with data obtained during winter from rockhopper penguins originating from the Falkland Islands showed that the area off the coast of Tierra del Fuego was used more or less exclusively by birds from Staten Island, whereas the Burdwood Bank was shared with penguins coming from southern colonies in the Falkland Islands. The implications of these findings are discussed with regard to (a) opposing population trends of rockhopper penguins in the Southwest Atlantic, and (b) the urgent need to establish adequate conservation measures for species and habitat protection.     

Mega-epibenthos at Bouvet Island (South Atlantic): a spatially isolated biodiversity hot spot on a tiny geological spot

Mega-epibenthic diversity was analysed using a seabed photography at four stations off Bouvet Island and one station at the Spiess Seamount in the South Atlantic. Surprisingly, the intermediate-scale diversity within the area of investigation was not lower compared to that on the Patagonian shelf and only moderately lower than that on the Antarctic continental shelf. This result is incompatible with Mac Arthur and Wilson’s Island Biogeography Theory describing species richness as a function of immigration of new species into an area and its extension. The relatively high species number and the very small extension of the Bouvet shelf compared to the much larger continental shelves of the other two areas can be explained by long-range dispersal of marine benthic animals in the Antarctic Circumpolar Current and high habitat heterogeneity. The observed uncoupling of intermediate-scale from large-scale background species diversity on the Antarctic shelf raises the question whether in these benthic systems an upper capacity limit for diversity exists.     

A comparative analysis of island floras challenges taxonomy‐based biogeographical models of speciation

Speciation on islands, and particularly the divergence of species in situ, has long been debated. Here, we present one of the first, complete assessments of the geographic modes of speciation for the flora of a small oceanic island. Cocos Island (Costa Rica) is pristine; it is located 550 km off the Pacific coast of Central America. It harbors 189 native plant species, 33 of which are endemic. Using phylogenetic data from insular and mainland congeneric species, we show that all of the endemic species are derived from independent colonization events rather than in situ speciation. This is in sharp contrast to the results of a study carried out in a comparable system, Lord Howe Island (Australia), where as much as 8.2% of the plant species were the product of sympatric speciation. Differences in physiography and age between the islands may be responsible for the contrasting patterns of speciation observed. Importantly, comparing phylogenetic assessments of the modes of speciation with taxonomy‐based measures shows that widely used island biogeography approaches overestimate rates of in situ speciation.     

Fine scale endemism on coral reefs: archipelagic differentiation in turbinid gastropods

The perceived wide geographic range of organisms in the sea, facilitated by ready dispersal of waterborne dispersal stages, is a challenge for hypotheses of marine speciation but a boon to efforts of marine conservation. Wide species ranges are especially striking in the reef-rich Indo-west Pacific, the largest and most diverse marine biogeographic region, extending across half the planet. The insular marine biota of the tropical Pacific is characterized by wide-ranging species and provides the most striking examples of long distance dispersal, with endemism largely confined to the most remote island groups. Here we show that the gastropod Astralium "rhodostomum" has developed endemic clades on almost every Pacific archipelago sampled, a pattern unprecedented in marine biogeography, and reminiscent of the terrestrial biota of oceanic islands. Mitochondrial DNA sequences indicate that this species-complex is comprised of at least 30 geographically isolated clades, separated by as little as 180 km. Evidence suggests that such fine scale endemism and high diversity is not exceptional, but likely characterizes a substantial fraction of the reef biota. These results imply that (1) marine speciation can regularly occur over much finer spatial scales than generally accepted, (2) the diversity of coral reefs is even higher than suggested by morphology-based estimates, and (3) conservation efforts need to focus at the archipelagic level in the sea as on land.     

Foraging a new trail with northern fur seals (Callorhinus ursinus): Lactating seals from islands with contrasting population dynamics have different foraging strategies,and forage at scales previously unrecognized by GPS interpolated dive data

We reconstructed the foraging tracks of lactating northern fur seals (Callorhinus ursinus) from two eastern Bering Sea islands (St. Paul Island and Bogoslof Island) using linear interpolation between GPS locations recorded at a maximum of four times per hour and compared it to tri‐axial accelerometer and magnetometer data collected at 16 Hz to reconstruct pseudotracks between the GPS fixes. The high‐resolution data revealed distances swum per foraging trip were much greater than the distances calculated using linearly interpolated GPS tracks (1.5 times further for St. Paul fur seals and 1.9 times further for Bogoslof fur seals). First passage time metrics calculated from the high resolution data revealed that the optimal scale at which the seals searched for prey was 500 m (radius of circle searched) for fur seals from St. Paul Island that went off‐shelf, and 50 m for fur seals from Bogoslof Island and surprisingly, 50 m for fur seals from St. Paul that foraged on‐shelf. These area‐restricted search scales were significantly smaller than those calculated from GPS data alone (12 km for St. Paul and 6 km for Bogoslof) indicating that higher resolution movement data can reveal novel information about foraging behaviors that have important ecological implications.     

Controls on reef development and the terrigenous-carbonate interface on a shallow shelf,Nicaragua (Central America)

Marine geology and physical oceanographic data collected during two field projects (∼4 months) on the Caribbean shelf of Nicaragua indicate a surprising dominance of carbonate deposition and reef growth on a shelf that is receiving an abnormally large volume of terrigenous sediments. High rainfall rates (∼400–500 cm/year), coupled with a warm tropical climate, encourage rapid denudation of the country’s central volcanic highland and transport of large volumes of terrigenous sediment and fresh water to the coast. Estimates suggest that three times more fresh water and fifteen times more sediment are introduced per unit length of coastline than on the east coast of the United States. Distribution of the terrigenous facies, development of carbonate sediment suites, and the location and quality of viable reefs are strongly controlled by the dynamic interaction near the coasts of highly turbid fresh to brackish water effluents from thirteen rivers with clear marine waters of the shelf. Oceanic water from the central Caribbean drift current intersects the shelf and moves slowely in a dominant northwest direction toward the Yucatan Channel. A sluggish secondary gyre moves to the south toward Costa Rica. In contrast, the turbid coastal water is deflected to the south in response to density gradients, surface water slopes, and momentum supplied by the steady northeast trade winds. A distinct two-layered flow is commonly present in the sediment-rich coastal boundary zone, which is typically 10–20 km wide. The low-salinity upper layer is frictionally uncoupled from the ambient shelf water and therefore can expand out of the normally coherent coastal boundary zone during periods of abnormal flooding or times when instability is introduced into the northeast trades. Reef distribution, abruptness of the terrigenous-carbonate interface, and general shelf morphology reflect the long-term dynamic structure of the shelf waters. A smooth-bottomed ramp of siliciclastic sands to silts and clays mantles the inner shelf floor in a linear belt paralleling the coast. This belt generally corresponds to the western flank of the coastal boundary zone. Occurrence of reefs is generally confined to areas outside this zone. Terrigenous clays and silts of the inner shelf are abruptly (<20 km from the coast) replaced byHalimeda-rich sediment of the middle and outer shelf. Within the carbonate facies belt, reef complexes thrive as small, isolated masses; large, reef-capped platforms; reef fringes around islands; and shelfedge structures with vertical relief that can exceed 25 m. In general, the frequency and proliferation of reefs increase away from the turbid coastal boundary layer and toward the cooler and saltier water that upwells at the shelf margin.     

Diversity of the free-living marine and freshwater Copepoda (Crustacea) in Costa Rica: a review

The studies on marine copepods of Costa Rica started in the 1990’s and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a moderate diversity of continental copepods (25 species), which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic). By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific) and 45 from the Caribbean coast (8% of species known from the Caribbean Basin). Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the marine habitats should emphasize oceanic environments including deep waters but also littoral communities. Several Costa Rican records of freshwater copepods are likely to represent undescribed species. Also, the biogeographic relevance of the inland copepod fauna of Costa Rica requires more detailed surveys.     

Distribution of recent benthic foraminifera on the Sunda Shelf (South China Sea)

In this study we investigate the species composition and spatial distribution patterns of Rose Bengal stained and unstained benthic foraminifera from the central part of the Sunda Shelf in the south-western South China Sea in relation to environmental factors. The uppermost centimetre of the surface sediments (> 150 μm) from 45 sites from inner (60 m) to outer shelf (226 m) water depths revealed 584 species including 443 stained species.The univariate analyses of individual species abundances and community parameters and next canonical correspondence analysis were used to relate the faunal data to a set of measured environmental parameters. Four biofacies recognised on the Sunda Shelf are most strongly correlated to water depth, primary production and sediment type of the habitat. The inner shelf biofacies (CCA cluster A), defined by Ammomassilina alveoliniformis and Asterorotalia pulchella, occurs in fine grained sediments classified as modern terrigenous mud in the region with the highest primary production values. The high-energy inner shelf biofacies (CCA cluster B), defined by Heterolepa dutemplei and Textularia lythostrota, occurs in modern terrigenous sand and silt dominated sediments, northeast from the Natuna Island. The high-energy outer shelf biofacies (CCA cluster C), defined by Cibicidoides pachyderma and Textularia bocki, is sandwiched between assemblages of biofacies D. It occurs in the region characterised by neritic relict sand. In the shallow-waters on the Sunda Shelf the relationship of benthic foraminiferal faunal composition to grain size of sediments indirectly signals the prevailing bottom hydrodynamic conditions. The dominance of the epibenthic foraminifera attached to bigger particles (e.g. Cibicides lobatulus, Planulina arimiensis) and much higher abundances of empty tests suggest greater current velocities northeast of Natuna Island. The outer shelf biofacies (CCA cluster D) is defined by Facetocochlea pulchra and Bulimina marginata. It occurs in an area covered with modern terrigenous silt and mud and is characterised by lower annual primary production, but seasonally influenced by weak upwelling.     

Distribution of gravel-sized empty tests of large benthic foraminifers as practical depositional indicators in tropical reef and shelf carbonate environments

To explore the utility of gravel-sized tests of large benthic foraminifers (LBFs) as practical paleoenvironmental indicators of tropical reef and shelf carbonate environments, depth and spatial distributions of gravel-sized empty tests of LBFs were examined using 39 surface sediment samples collected from depths shallower than 200 m off the west coast of Miyako Island (Ryukyu Islands, northwest Pacific). Distributions of the LBF tests were mainly related to water depth, topography, and substrate type. Q-mode cluster analysis based on the binary (presence/absence) data of LBF associations (4–2-mm size fraction) clearly delineates four depositional environments: bay, back reef to fore reef, flat shelf, and shelf slope. Application of this modern dataset to fossil LBF data from larger foraminiferal limestones of the Pleistocene Ryukyu Group indicate that a test section was deposited in an outer flat shelf at depths between 54 and 99 m. Comparisons of these results with previous reports suggest that our foraminiferal analysis using gravel-sized tests is methodologically easier than conventional analyses including smaller sized tests to distinguish similar levels of depositional environments. However, taxonomic and environmental similarities make the applicability of this dataset to fossil LBF data from Quaternary tropical carbonate environments in the northwest Pacific.     

Rotifer distributions in the coastal waters of the northeast Pacific Ocean

Absolute abundance of rotifers was assessed from 5 to 80 km across the continental shelf off of the southern Oregon coast (U.S.A.) in the northeast Pacific Ocean. A total of 97 vertically stratified water samples were collected at 49 stations from two depths, 3 and 30 m. Coastal upwelling conditions were indicated, with decreased temperature, increased salinity and higher chlorophyll-a concentrations closer to shore. Two rotifer genera, Synchaeta and Trichocercaoccurred within 16 km of shore with densities increasing closer to shore. Synchaeta reached densities of 64 inds l^–1 while Trichocerca was sparse (<1 inds. l^–1). Rotifers were most abundant at 3 m and the densest aggregations appear to be associated with estuary outlets, suggesting that estuaries may be important in exporting rotifers to nearshore coastal waters.     

Genetic exchange between anchialine cave populations by means of larval dispersal: the case of a new gastropod species Neritilia cavernicola

Despite being limited to caves, many anchialine taxa have disjunct insular distributions, which raises questions about their origins and colonization history. This study deals with the new gastropod Neritilia cavernicola sp. n. (Neritopsina: Neritiliidae) from anchialine caves on two islands in the Philippines that are separated by the deep Bohol Strait and situated 200 km apart along the coastline of Cebu Island. Neritilia cavernicola is an obligate stygobiont and most closely resembles Neritilia littoralis , which lives in interstitial waters of the Nansei-shoto Islands, Japan. Its eggs and larval shells are identical to those of other Neritilia species, despite their different adult habitats. This suggests a marine planktotrophic phase (as occurs in amphidromous riverine species of Neritilia ), and consequent migration between islands via ocean currents. Here we present the first genetic structure for anchialine cave organisms; comparisons of 1276 bp sequences from mitochondrial cytochrome oxidase I show no evidence of genetic isolation between the islands. All individuals evidently are part of a panmictic population and the low vagility of adults and their seemingly isolated cave habitats do not limit gene flow in N. cavernicola . This migration model, based on marine larval dispersal, may be widely applicable to anchialine stygobites with insular distributions, as many such organisms (including shrimps, crabs and fishes) are phylogenetically allied to amphidromous species.     

Habitat use by three rat species (

Ship rats (Rattus rattus) were removed from sites on Pearl Island, southern Stewart Island, in 2004 and 2005, to test whether they excluded Pacific rats (R. exulans) or Norway rats (R. norvegicus) or both from podocarp-broadleaf forest. As predators can influence habitat use in rodents, Pearl Island was selected because no mammalian predators of rodents are present. Rats were trapped in two other habitats to clarify rat distribution on the island and to obtain samples for stable isotope investigation of food partitioning within habitats. The experimental removal of ship rats failed, as Pacific rats were found to share forest and shrubland with ship rats. This result contrasted with the restricted distribution of Pacific rats on Stewart Island. Ship rats were ubiquitous, and appear to have been the dominant species in podocarp-broadleaf forest on Pearl Island. The largest species, the Norway rat, was trapped only on the foreshore of Pearl Island, but on Stewart Island it is more widespread. Ship rats and Norway rats were partitioning the coastal habitat by exploiting different food sources. Stable isotopic ratios (δ¹⁵N and δ¹³C) in muscle samples from Norway rats revealed a strong marine signature, suggesting intensive foraging in the intertidal zone. Ship rats trapped in the same habitat exhibited mixed terrestrial and marine sources in their diet. There was little obvious partitioning between ship rats and Pacific rats in forest, except a possible delay in breeding in Pacific rats relative to ship rats. Whether Norway rats select the intertidal zone to forage, or were excluded from forest by ship rats is unknown, but competitive exclusion is likely. Estimated densities of rats were low (2.1–5.1 rats ha^-1 in forest, 1.42 rats ha^-1 in shrubland) and similar to other New Zealand sites with low soil fertility. Further research will be required to elucidate the roles of food quality, habitat structure and predation in facilitating habitat selection in these species.     

Environmental confirmation of multiple ice age refugia for Pacific cod, Gadus macrocephalus

The concept of species surviving through quaternary climatic extremes by retreating to glacial refugia, and then evolving genetically during re-population movements of the following interglacial, has been in the literature for over 40 years. Recently, advances in genetic analysis have enabled this concept to be validated and theories regarding population expansions and contractions to be built. For the major Northern Hemisphere species of cod, Gadus morhua (Atlantic cod) and Gadus macrocephalus (Pacific cod), genetic analysis has suggested retreat to separate refugia on both sides of their respective ocean basins during the last glacial period. Ecosystem niche modelling has previously confirmed that environmental conditions during the last glacial were compatible with the existence of these separate refugia for Atlantic cod. Here it is shown that such modelling also confirms a reduced core glacial distribution for G. macrocephalus, but probable refugia on either side of the Pacific. Existing mitochondrial DNA analyses suggest two separate glacial populations in the northwest Pacific, which modelling confirms, with predicted separate marine refugia in the land-locked Sea of Japan basin and the Sea of Okhotsk. Existing mitochondrial DNA for the northeast Pacific populations is less conclusive regarding whether there were one or two separate refugia off this coast, and their location. Using environmental niche models this study shows the glacial NE Pacific environment could support two marine refugia, one centred in the Aleutians/Gulf of Alaska and the other off British Columbia. The intervening Cordilleran Ice Sheet, and the glacially sub-aerial and ice-free Queen Charlotte Islands shelf, is hypothesised to have constrained exchange between glacial stocks either side of the Islands. The postulated southern marine refugium is off-shore from an established terrestrial refugium, suggesting greater dependence of species and ecosystems during environmental change. An earth system approach to evolutionary change could enhance understanding of past and future ecosystems.     

Infestation of walleye pollock with the parasitic copepod Haemobaphes diceraus Wilson, 1917 (Copepoda: Pennellidae) in waters of Sakhalin and the Kuril Islands

The infestation of walleye pollock with a parasitic copepod Haemobaphes diceraus at the coasts of Sakhalin and the Kuril Islands was studied during the spring of 2008. The extensiveness of the infestation in Pacific waters of the northern Kurils was 1.85–1.97%. In the southern Kurils it was from 2.0% (northeast of Iturup Island) to 7.41% (Prostor Bay), in the Tatar Strait it was 1.61%, and off northern Sakhalin Island it was 0.46%.     

A most isolated benthos: coastal bryozoans of Bouvet Island

Bouvet Island is, uniquely, thousands of km from the next nearest land, even other islands. Its Southern Ocean location, isolation and the exposure of its surrounding cliffs have resulted in only rare visits by ship and its coastal marine fauna is little known. For animal taxa with non-pelagic larvae, such as cheilostome bryozoans, the shelf environment of Bouvet is a rare example of isolated oceanic communities. Agassiz trawl samples of the 2003 ANT XXI-2 cruise of the PFS Polarstern collected a total of 18 species of cheilostomes at four sites around Bouvet Island. Of these only four had been reported before amongst the 20 species of cheilostome previously known from this locality. Furthermore eight of the genera are reported for the first time from Bouvet Island. The assemblages were dominated by Austroflustra vulgaris, and in one case Nematoflustra flagellata. The bryozoan fauna seems to be depauperate and bears only low (32% at species and 46% at genus level) similarity to any location within 3,000 km. Its species composition is typically Southern Ocean, with most affinity to the Scotia Arc and Weddell Sea whereas at generic level it is most similar to the Subantarctic Prince Edward Archipelago.     

A large population of king crabs in Palmer Deep on the west Antarctic Peninsula shelf and potential invasive impacts

Lithodid crabs (and other skeleton-crushing predators) may have been excluded from cold Antarctic continental shelf waters for more than 14 Myr. The west Antarctic Peninsula shelf is warming rapidly and has been hypothesized to be soon invaded by lithodids. A remotely operated vehicle survey in Palmer Deep, a basin 120 km onto the Antarctic shelf, revealed a large, reproductive population of lithodids, providing the first evidence that king crabs have crossed the Antarctic shelf. DNA sequencing and morphology indicate the lithodid is Neolithodes yaldwyni Ahyong & Dawson, previously reported only from Ross Sea waters. We estimate a N. yaldwyni population density of 10 600 km(-2) and a population size of 1.55 × 10(6) in Palmer Deep, a density similar to lithodid populations of commercial interest around Alaska and South Georgia. The lithodid occurred at depths of more than 850 m and temperatures of more than 1.4°C in Palmer Deep, and was not found in extensive surveys of the colder shelf at depths of 430-725 m. Where N. yaldwyni occurred, crab traces were abundant, megafaunal diversity reduced and echinoderms absent, suggesting that the crabs have major ecological impacts. Antarctic Peninsula shelf waters are warming at approximately 0.01°C yr(-1); if N. yaldwyni is currently limited by cold temperatures, it could spread up onto the shelf (400-600 m depths) within 1-2 decades. The Palmer Deep N. yaldwyni population provides an important model for the potential invasive impacts of crushing predators on vulnerable Antarctic shelf ecosystems.     

Late Holocene variability in pelagic fish scales and dinoflagellate cysts along the west coast of Vancouver Island, NE Pacific Ocean

Fish stocks and dinoflagellates are essential components of the marine food chain. Sediment cores from a predominantly anoxic basin in Effingham Inlet, Vancouver Island, British Columbia, archive a late Holocene (500–5300 years BP) record of paleoproductivity in the North American Coastal Upwelling Domain (CUD). We present evidence that late Holocene changes in the dinoflagellate cyst assemblages, sedimentary record, and fish stocks in the northeastern Pacific Ocean fluctuated, at least partially, in accordance with regional and global climate cycles.Principal components analysis (PCA), and trend, wavelet and spectral analyses were used to identify relationships, cycles and trends in sediment grey-scale values, and the abundances of fish scales and dinoflagellate cysts on centennial to millennial time scales. Most observed cycles fluctuated in intensity over time, particularly following transition of the regional climate to a higher rainfall phase that impacted coastal oceanic dynamics 3400 ± 150 years ago. Correlation of the marine paleoproductivity records observed in Effingham Inlet with solar influenced climate proxy cycles observed in the North Atlantic region indicates that solar forcing at different scales might have influenced the climate in the northeast Pacific as well. In particular an 1100- to 1400-year cycle in regional climate is well represented in the fish productivity proxy and sedimentological record. It was also observed that colder water, high-productivity, Selenopemphix nephroides and anchovy-dominated “Anchovy Regime” ecosystems alternate with warmer water, herring-dominated “Herring Regime” ecosystems at millennial time scales. The fish scale record preserved in Effingham Inlet indicates that the NE Pacific is now in transition from an ‘anchovy-’ to a ‘herring’-dominated regime.     

The eastern Pacific species of Bathygobius (Perciformes: Gobiidae)

The circumtropical gobiid genus Bathygobius Bleeker is defined and three Eastern Pacific species are redescribed, with first dorsal fin pattern and postorbital blotches being shown to be additional characters of diagnostic value. Two mainland species are recognised, the Mexican-Panamanian B. ramosus Ginsburg 1947 and the Panamanian B. andrei (Sauvage 1880). B. ramosus is now reported from Clarión Island, Revillagigedos, and also from Cocos Island. Meristic variation of ramosus is tabulated for local populations and PCA analysis of their morphometry suggests regional differentiation in this species, with Tres Marias and Revillagigedos populations clustering away from mainland and Montuosa material. An insular species, B. lineatus (Jenyns 1842) from the Galapagos is defined, with B. arundelii (Garman 1899) from Clipperton Island and B. l. lupinus Ginsburg 1947 from Lobos de Afuera, off Peru, placed as nominal subspecies of lineatus. This species resembles the Indo-west Pacific B. fuscus and Atlantic basin B. soporator more closely than it does ramosus and andrei and may be the product of transpacific dispersal. A similar origin for B. ramosus is discussed but it seems more likely that both B. ramosus and B. andrei have Caribbean sister species.     

Rapid, independent evolution of flightlessness in four species of Pacific Island rails (Rallidae): an analysis based on mitochondrial sequence data

Flightless rails were once ubiquitous in the avifauna of Pacific oceanic islands. Most species have become extinct since human colonization of islands began about 2000 years ago. In this study, we use mitochondrial sequence data to estimate the phylogenetic relationships and ages of four species of flightless insular rails in the genus Porzana : palmeri , from Laysan Island in the Hawaiian archipelago; sandwichensis , from the island of Hawaii; monasa , from Kosrae Island in Micronesia; and atra , from Henderson Island in the Pitcairn group. Although all four species survived into historic times, all but atra are now extinct. The optimal trees show that palmeri is descended from Porzana pusilla , a volant crake distributed widely throughout the Old World. Porzana sandwichensis , P. monasa , and P. atra are each descended from the lineage leading to P. tabuensis , a volant rail widespread in northern and eastern Australia and on islands north to Micronesia and the Philippines and east through Polynesia. Loss of flight appears to have evolved rapidly in these insular rails, based on both sequence divergence values and data on the ages of the islands. In the case of the Laysan Rail ( palmeri ), divergences including loss of flight probably evolved in less than 125,000 years .     

The area of potential shallow-water tropical and subtropical coral ecosystems in the United States

Geographic information system-based analysis was used to derive comprehensive, consistent estimates of the potential area of broadly defined, shallow-water, tropical and subtropical coral ecosystems within the territorial sea and exclusive economic zone of the United States. A coral ecosystem is composed of habitats including unconsolidated sediment, mangrove, hermatypic coral, colonized hardbottom, and submerged vegetation, and major structural zones like reef crest, lagoon, and fore reef. This broad definition reflects the importance of both reef and non-reef habitats and structural zones in the function of these ecosystems. Nautical charts, published by the National Oceanic and Atmospheric Administration’s Office of the Coast Survey, provide a consistent source of 10-fathom (∼18 m) and 100-fathom (∼183 m) depth curve information. The 10-fathom or 100-fathom depth curves are used as surrogates for the potential distribution and extent of shallow-water coral ecosystems in tropical and subtropical U.S. waters. An estimated 36,813 sq·km area has been identified where coral ecosystems can potentially be found in waters less than 10 fathoms (18 m) deep. In addition, an estimated 143,059 sq·km area has been identified where coral ecosystems potentially can be found in U.S. waters at depths down to 100 fathoms (183 m). Results also indicate that previous studies underestimated the extent of potential coral ecosystems for some locations in U.S. tropical and subtropical waters by as much as 100% and that the regional distribution of coral ecosystems has been incorrectly reported.