Evolution of Nemertesia hydroids (Cnidaria: Hydrozoa,Plumulariidae) from the shallow and deep waters of the NE Atlantic and western Mediterranean

Moura, C. J., Cunha, M. R., Porteiro, F. M., Yesson, C. & Rogers, A. D. (2011) Evolution of Nemertesia hydroids (Cnidaria: Hydrozoa, Plumulariidae) from the shallow and deep waters of the NE Atlantic and Western Mediterranean. —Zoologica Scripta, 41, 79–96. Hydroid species from the genus Nemertesia develop some of the largest and most complex hydrozoan colonies. These colonies are abundant and ecologically important in both shallow and deep waters worldwide. Here, we analyse the systematics of most Nemertesia species from the NE Atlantic and Mediterranean using morphology and phylogenetic inferences of 16S rRNA haplotype data. Phylogeographical analysis revealed multiple movements of taxa to and from the Mediterranean after the Messinian salinity crisis through shallow and deep waters. The nominal species Nemertesia belini and Nemertesia antennina revealed multiple genetic lineages representing cryptic species diversity. Molecular phylogenetic evidence was supported by consistent phenotypic differences between lineages, and three and seven putative species were resolved within the N. belini and N. antennina complexes, respectively. Three putative species of the N. antennina complex found at different seamounts of Azores grouped in a clade clustered amongst the other four cryptic species present at neighbouring bathyal localities of the Gulf of Cadiz. These cryptic species, mostly from the deep sea, form a clade distantly related to the typical N. antennina from European coastal waters. Depth or environmental correlates of depth seem to influence the reproductive strategies of Nemertesia colonies and ultimately speciation. In particular, speciation of these hydroids must have been influenced by hydrography, habitat heterogeneity, isolation by distance and larval dispersal capacity. The deep sea is shown as an important environment in the generation and accumulation of lineages that may occasionally invade coastal waters in the NE Atlantic. Glacial cycles of cooling, along with changes in sea level, and eradication of some coastal faunas likely facilitated speciation and evolutionary transitions from deep to shallow waters.     

Phylogenetic revision of the Hippasterinae (Goniasteridae; Asteroidea): systematics of deep sea corallivores,including one new genus and three new species

The Hippasterinae is a subfamily within the Goniasteridae, consisting of five genera and 26 species, which occur in cold‐water settings ranging from subtidal to abyssal depths. All known genera were included in a cladistic analysis resulting in two most parsimonious trees, supporting the Hippasterinae as monophyletic. Our review supports Sthenaster emmae gen. et sp. nov. as a new genus and species from the tropical Atlantic and two new Evoplosoma species, Evoplosoma claguei sp. nov. and Evoplosoma voratus sp. nov. from seamounts in the North Pacific. Hippasteria caribaea is reassigned to the genus Gilbertaster, which previously contained a single Pacific species. Our analysis supports Evoplosoma as a derived deep water lineage relative to its continental‐shelf, shallow water sister taxa. The genus Hippasteria contains approximately 15 widely distributed, but similar‐looking species, which occur in the northern and southern hemispheres. Except for Gilbertaster, at least one species in each genus has been observed or is inferred to prey on deep‐sea corals, suggesting that this lineage is important to the conservation of deep‐sea coral habitats. The Hippasterinae shares several morphological similarities with Circeaster and Calliaster, suggesting that they may be related. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 266–301.     

Southern African skate biodiversity and distribution

The skates (Family Rajidae) have 12 genera and possibly 28 species off southern Africa (southern Angola, Namibia, South Africa and Mozambique). The geographic and bathymetric distribution and the taxonomic composition of the southern African skate fauna are analysed and the distribution mapped. The southern African skate fauna is best known off the temperate west coast of South Africa from the intertidal to approximately 1,200 meters, but poorly known below 1,200 m and sketchily known in warm-temperate and tropical parts of the area. Southern African skates of the temperate continental shelves above 100 m are not diverse and regularly include one species of the genus Dipturus, one species of Leucoraja, two species of Raja (including R. straeleni, the most abundant skate in southern African waters) and the giant skate Rostroraja alba. All of these skates are ‘shelf overlap’ species that range onto the outer shelves and uppermost slopes, and none are confined to inshore environments. Skate diversity increases on the outer shelves and upper slopes. At least half of the skate species are endemic to the southern African region; other species also occur off East or West Africa, a few extend to European waters, and records of one species, Amblyraja taaf, appear to be of strays from nearby sub-Antarctic seas. The genus Bathyraja and softnose skate group (Arhynchobatinae) are surprisingly limited (a single species) in deep-water off southern Africa (unlike other regions including the Antarctic), and almost all of southern African skates are members of the Rajinae. Amongst rajines, the tribes Amblyrajini (Amblyraja, two species, Leucoraja, two species, and Rajella, five species) Rajini (Dipturus, six species, Okamejei, one species, Raja, two species, and Rostroraja, one species), and Anacanthobatini (Anacanthobatis, two species, and Cruriraja, three species) predominate, while Gurgesiellini has a species of Neoraja and possibly two of Malacoraja.     

Tri-locus sequence data reject a “Gondwanan origin hypothesis” for the African/South Pacific crab genus Hymenosoma

Crabs of the family Hymenosomatidae are common in coastal and shelf regions throughout much of the southern hemisphere. One of the genera in the family, Hymenosoma, is represented in Africa and the South Pacific (Australia and New Zealand). This distribution can be explained either by vicariance (presence of the genus on the Gondwanan supercontinent and divergence following its break-up) or more recent transoceanic dispersal from one region to the other. We tested these hypotheses by reconstructing phylogenetic relationships among the seven presently-accepted species in the genus, as well as examining their placement among other hymenosomatid crabs, using sequence data from two nuclear markers (Adenine Nucleotide Transporter [ANT] exon 2 and 18S rDNA) and three mitochondrial markers (COI, 12S and 16S rDNA). The five southern African representatives of the genus were recovered as a monophyletic lineage, and another southern African species, Neorhynchoplax bovis, was identified as their sister taxon. The two species of Hymenosoma from the South Pacific neither clustered with their African congeners, nor with each other, and should therefore both be placed into different genera. Molecular dating supports a post-Gondwanan origin of the Hymenosomatidae. While long-distance dispersal cannot be ruled out to explain the presence of the family Hymenosomatidae on the former Gondwanan land-masses and beyond, the evolutionary history of the African species of Hymenosoma indicates that a third means of speciation may be important in this group: gradual along-coast dispersal from tropical towards temperate regions, with range expansions into formerly inhospitable habitat during warm climatic phases, followed by adaptation and speciation during subsequent cooler phases.     

Isolation of alkane‐degrading bacteria from deep‐sea Mediterranean sediments

Aims: To isolate and identify alkane‐degrading bacteria from deep‐sea superficial sediments sampled at a north‐western Mediterranean station. Methods and Results: Sediments from the water/sediment interface at a 2400 m depth were sampled with a multicorer at the ANTARES site off the French Mediterranean coast and were promptly enriched with Maya crude oil as the sole source of carbon and energy. Alkane‐degrading bacteria belonging to the genera Alcanivorax, Pseudomonas, Marinobacter, Rhodococcus and Clavibacter‐like were isolated, indicating that the same groups were potentially involved in hydrocarbon biodegradation in deep sea as in coastal waters. Conclusions: These results confirm that members of Alcanivorax are important obligate alkane degraders in deep‐sea environments and coexist with other degrading bacteria inhabiting the deep‐subsurface sediment of the Mediterranean. Significance and Impact of the Study: The results suggest that the isolates obtained have potential applications in bioremediation strategies in deep‐sea environments and highlight the need to identify specific piezophilic hydrocarbon‐degrading bacteria (HCB) from these environments.     

The ‘Oxycythereis’ problem: taxonomy and palaeobiogeography of deep‐sea ostracod genera Pennyella and Rugocythereis

Systematic revision of the globally distributed deep‐sea ostracod genera Pennyella Neale, 1974 and Rugocythereis Dingle, Lord and Boomer, 1990, which have been considered to correspond, at least partially, to nomen nudum but widely used genus name ‘Oxycythereis,’ was conducted to reduce taxonomic uncertainty of these important components of the Modern and fossil deep‐sea ostracod community. Approximately 100 specimens from 18 species were examined, ranging in age from the Cretaceous to the present day. Nine new species are described: Pennyella rexi, Pennyella sanfordae, Pennyella liowae, Pennyella schellenbergi, Pennyella majorani, Pennyella iani, Pennyella ayressi, Rugocythereis melonis and Rugocythereis zarikiani. Emended generic concepts of Pennyella and Rugocythereis are proposed, and the palaeobiogeographical distributions of these two genera are discussed.     

Distributional range extension of the seagrass Halophila nipponica into coastal waters off the Korean peninsula

Eight temperate seagrass species (five in the genus Zostera, two in the genus Phyllospadix, and Ruppia maritima) have been previously reported in coastal waters off the Korean peninsula, which lies between 33°N and 43°N. Recently, a species of Halophila, a genus which occurs predominantly in tropical and subtropical areas, has been observed on the southern coast of Korea for the first time. The species was identified as Halophila nipponica. H. nipponica is distributed in warm temperate regions of Japan influenced by the warm Tsushima Current and was previously unknown outside the Japanese archipelago. Thus, we are able to report a range extension into Korea. The Korean Halophila meadow that we observed covered an area of about 2.1 ha, with average shoot density of about 1300 m⁻². We measured morphological features of vegetative and reproductive organs between June and September 2007. Morphological and reproductive features of the Halophila species in Korea were similar to those of the species in Japan. Increased water temperature in the coastal waters of Korea may at least partially account for the persistence of this new population.     

Phylogeography of the Indo‐West Pacific maskrays (Dasyatidae,Neotrygon): a complex example of chondrichthyan radiation in the Cenozoic

Maskrays of the genus Neotrygon (Dasyatidae) have dispersed widely in the Indo‐West Pacific being represented largely by an assemblage of narrow‐ranging coastal endemics. Phylogenetic reconstruction methods reproduced nearly identical and statistically robust topologies supporting the monophyly of the genus Neotrygon within the family Dasyatidae, the genus Taeniura being consistently basal to Neotrygon, and Dasyatis being polyphyletic to the genera Taeniurops and Pteroplatytrygon. The Neotrygon kuhlii complex, once considered to be an assemblage of color variants of the same biological species, is the most derived and widely dispersed subgroup of the genus. Mitochondrial (COI, 16S) and nuclear (RAG1) phylogenies used in synergy with molecular dating identified paleoclimatic fluctuations responsible for periods of vicariance and dispersal promoting population fragmentation and speciation in Neotrygon. Signatures of population differentiation exist in N. ningalooensis and N. annotata, yet a large‐scale geological event, such as the collision between the Australian and Eurasian Plates, coupled with subsequent sea‐level falls, appears to have separated a once homogeneous population of the ancestral form of N. kuhlii into southern Indian Ocean and northern Pacific taxa some 4–16 million years ago. Repeated climatic oscillations, and the subsequent establishment of land and shallow sea connections within and between Australia and parts of the Indo‐Malay Archipelago, have both promoted speciation and established zones of secondary contact within the Indian and Pacific Ocean basins.     

Global seagrass distribution and diversity: A bioregional model

Seagrasses, marine flowering plants, are widely distributed along temperate and tropical coastlines of the world. Seagrasses have key ecological roles in coastal ecosystems and can form extensive meadows supporting high biodiversity. The global species diversity of seagrasses is low (< 60 species), but species can have ranges that extend for thousands of kilometers of coastline. Seagrass bioregions are defined here, based on species assemblages, species distributional ranges, and tropical and temperate influences. Six global bioregions are presented: four temperate and two tropical. The temperate bioregions include the Temperate North Atlantic, the Temperate North Pacific, the Mediterranean, and the Temperate Southern Oceans. The Temperate North Atlantic has low seagrass diversity, the major species being Zostera marina, typically occurring in estuaries and lagoons. The Temperate North Pacific has high seagrass diversity with Zostera spp. in estuaries and lagoons as well as Phyllospadix spp. in the surf zone. The Mediterranean region has clear water with vast meadows of moderate diversity of both temperate and tropical seagrasses, dominated by deep-growing Posidonia oceanica. The Temperate Southern Oceans bioregion includes the temperate southern coastlines of Australia, Africa and South America. Extensive meadows of low-to-high diversity temperate seagrasses are found in this bioregion, dominated by various species of Posidonia and Zostera. The tropical bioregions are the Tropical Atlantic and the Tropical Indo-Pacific, both supporting mega-herbivore grazers, including sea turtles and sirenia. The Tropical Atlantic bioregion has clear water with a high diversity of seagrasses on reefs and shallow banks, dominated by Thalassia testudinum. The vast Tropical Indo-Pacific has the highest seagrass diversity in the world, with as many as 14 species growing together on reef flats although seagrasses also occur in very deep waters. The global distribution of seagrass genera is remarkably consistent north and south of the equator; the northern and southern hemispheres share ten seagrass genera and only have one unique genus each. Some genera are much more speciose than others, with the genus Halophila having the most seagrass species. There are roughly the same number of temperate and tropical seagrass genera as well as species. The most widely distributed seagrass is Ruppia maritima, which occurs in tropical and temperate zones in a wide variety of habitats. Seagrass bioregions at the scale of ocean basins are identified based on species distributions which are supported by genetic patterns of diversity. Seagrass bioregions provide a useful framework for interpreting ecological, physiological and genetic results collected in specific locations or from particular species.     

Nematode assemblages from the Kandalaksha Depression (White Sea, 251–288 m water depth)

The shallow-water nematodes of the White Sea are relatively well studied; however, information on the nematode fauna inhabiting the deepest part of this sea is very scarce. The composition of the nematode assemblages (at species and genus level) was studied in samples collected during four sampling occasions in the deepest part of the Kandalaksha Depression (the White Sea) in July 1998, October 1998, May 1999, and November 1999. Samples were collected from a depth of 251–288 m with the aid of a multicorer. In total, 59 nematode morphotypes belonging to 37 genera and 18 families were distinguished. The genera Sabatieria and Filipjeva dominated at all stations, followed by Aponema, Desmoscolex, and Quadricoma. The composition of the dominant genera can be considered typical for this depth range in temperate and Arctic waters, although Filipjeva and Aponema were among the dominant genera for the first time. The most abundant species were Sabatieria ornata, Aponema bathyalis, and Filipjeva filipjevi. In general, diversity of the nematode assemblages was lower than in the temperate and Arctic continental shelf and slope with reduced evenness and species richness. The evenness of nematode assemblages and other diversity indices decreased with increasing sediment depth. Based on the valid species and genera recorded, the nematode fauna of the Kandalaksha Depression showed a higher resemblance to that found in the shallow waters of Kandalaksha Bay.     

Mangrove expansion and salt marsh decline at mangrove poleward limits

Mangroves are species of halophytic intertidal trees and shrubs derived from tropical genera and are likely delimited in latitudinal range by varying sensitivity to cold. There is now sufficient evidence that mangrove species have proliferated at or near their poleward limits on at least five continents over the past half century, at the expense of salt marsh. Avicennia is the most cold‐tolerant genus worldwide, and is the subject of most of the observed changes. Avicennia germinans has extended in range along the USA Atlantic coast and expanded into salt marsh as a consequence of lower frost frequency and intensity in the southern USA. The genus has also expanded into salt marsh at its southern limit in Peru, and on the Pacific coast of Mexico. Mangroves of several species have expanded in extent and replaced salt marsh where protected within mangrove reserves in Guangdong Province, China. In south‐eastern Australia, the expansion of Avicennia marina into salt marshes is now well documented, and Rhizophora stylosa has extended its range southward, while showing strong population growth within estuaries along its southern limits in northern New South Wales. Avicennia marina has extended its range southwards in South Africa. The changes are consistent with the poleward extension of temperature thresholds coincident with sea‐level rise, although the specific mechanism of range extension might be complicated by limitations on dispersal or other factors. The shift from salt marsh to mangrove dominance on subtropical and temperate shorelines has important implications for ecological structure, function, and global change adaptation.     

Molecular and morphological comparison of larvae and juveniles of five species of callionymids,with ontogenetic evidence on the monophyly of Repomucenus (Callionymidae)

Dragonet fishes (Callionymidae) are benthic inhabitants of shallow waters, even in tidal pools, down to depths below 900 m in all subtropical, tropical and temperate oceans. The family comprises 200 species in 20 genera worldwide, of which 18 species in 6 genera occur in Korea. Classification within the family Callionymidae has been controversial because of the differing proposals of Fricke and Nakabo (Fishes of Japan with pictorial keys to the species, 1983). For example, Fricke suggested genus Repomucenus and Bathycallionymus, whose genera contains most callionymid species in Korean waters, as junior synonym of genus Callionymus while Nakabo (Fishes of Japan with pictorial keys to the species, 1983) suggested as valid. In such cases, when classifications of adults have taxonomic contention, examination of larval characters may prove informative. Therefore, in this study, the authors conducted comprehensive molecular and morphological analyses on larvae and juveniles of five species in the genus Repomucenus and discussed their taxonomic status within the family Callionymidae. Larval and juvenile callionymids show high morphological similarities during their ontogenetic development. Nonetheless, the following morphological differences were observed in melanophore distribution and preopercular spine development: (a) stellate or punctate melanophores in Bathycallionymus kaianus vs. branched melanophores in genus Repomucenus, (b) melanophores on the abdominal cavity gradually disappearing in B. kaianus vs. gradually becoming prominent in Repomucenus and (c) preopercular spine development giving rise to one perpendicular spine in B. kaianus vs. two or three spines in Repomucenus. Molecular analysis based on 16S ribosomal RNA showed similar results to the morphological analysis. Genera Bathycallionymus and Repomucenus showed significant genetic distance (d = 0.113–0.120); moreover, genus Callionymus, which was suggested as a senior synonym of genus Bathycallionymus and Repomucenus by Fricke (Journal of Natural History, 2014, 48, 2419–2448), also showed considerable difference (d = 0.226–0.246). In the present study, the monophyly of genus Repomucenus seemed well supported by the results of morphological and molecular analyses of larval stage Callionymidae.     

A molecular phylogenetic appraisal of the systematics of the Aglaopheniidae (Cnidaria: Hydrozoa,Leptothecata) from the north‐east Atlantic and west Mediterranean

The hydrozoan family Aglaopheniidae (Cnidaria) is widespread worldwide and contains some of the most easily recognizable hydroids because of their large colony size and characteristic microscopic structure. The systematics of the group has, however, been controversial and dedicated molecular analyses are lacking. We therefore analysed existing and new 16S rRNA sequences of Aglaopheniidae, in a total of 98 16S sequences corresponding to 25 putative species (25 nominal and three undescribed) from seven genera. The monophyly of the subfamilies Gymnangiinae and Aglaopheniinae, and tribes Aglaopheniini and Cladocarpini were not verified with 16S sequence data. The genera Gymnangium and Aglaophenia can only be considered valid if both Gymnangium gracicaule and Aglaophenia latecarinata are removed from their respective genera. The phenotypically similar Cladocarpus and Streptocaulus are probably monophyletic and clearly distinct genetically. The genus Lytocarpia may be polyphyletic. The nominal species Aglaophenia pluma, Aglaophenia tubiformis, and Aglaophenia octodonta are probably conspecific, as are also the species Aglaophenia acacia and Aglaophenia elongata. The 16S data revealed the existence of two potentially unnamed species of Aglaophenia respectively from the Azores and Madeira. The phylogeographical structure of the taxa with the greatest representation of haplotypes from the north‐east Atlantic and Mediterranean, revealed the influence of Mediterranean waters in Madeira and the Azores, and gene flow between deep waters of the Mediterranean and Atlantic. The last glaciations in Europe may have caused genetic bottlenecks but also high intraspecific haplotype diversity. Finally, Macrorhynchia philippina was detected in samples from Madeira and possibly represents an invasive species. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 717–727.     

Tasmanomysis oculata n.g. n.sp. from Tasmanian waters (Crustacea: Mysidacea: Mysini)

Tasmanomysis oculata n.g. n.sp. belonging to the Tribe Mysini is described from the coastal waters of southern Tasmania. This new genus superficially resembles the monospecific genus Arthromysis Colosi,1924 known only from the Straits of Magellan. The form of the pleopods in the male together with the segmentation of the thoracic legs and shape of the telson clearly distinguish the two genera.     

DIVERSITY AND MORPHOLOGY OF SKELETONEMA SPECIES IN SOUTHERN BRAZIL,SOUTHWESTERN ATLANTIC OCEAN1

We examined the morphology of Skeletonema species occurring in coastal waters of southern Brazil, on the basis of LM, SEM, and TEM analyses of six isolated strains and of 13 field samples from the Patos Lagoon estuary and the adjacent Cassino Beach. We concluded that the genus Skeletonema is highly diverse in coastal waters of southern Brazil, with the occurrence of four confirmed species: S. costatum, S. pseudocostatum, S. potamos, and S. tropicum. In addition, EM details must still be provided for S. menzelii, and genetic studies should be conducted to confirm the identity of S. cf. grethae and S. subsalsum. The high diversity in this geographic area can be attributed to the proximity of the Subtropical Convergence and to the freshwater ecosystems of Patos Lagoon and La Plata River that favor the presence of warm‐, cold‐, and brackish‐water species.     

Phragmoplastins,the Trentepohliales,and the Evolution of the Cytokinesis in Green Plants

Representatives of the monophyletic Trentepohliales are widely distributed in the tropics, subtropics, and temperate regions worldwide. They grow in soil, or are epilithic, epiphytic or endophytic. The family comprises approximately 70 species placed in at least four genera (Trentepohlia, Cephaleuros, Phycopeltis and Stomatochroon), with Trentepohlia sensu lato (including Printzina and Physolinum) accounting for half of the species in this family. PCR amplification and sequencing of the 18 SSU rDNA of 18 isolates of the Trentepohliaceae were used to assess the monophyly of the genus Cephaleuros and to determine the phylogenetic relationships among species of Trentepohlia sensu lato. Distance, Parsimony, and Maximum Likelihood analyses indicate that Trentepohlia sensu lato is basal and includes two species recently transferred to Phycopeltis (P. umbrina) and Printzina (P. lagenifera). In contrast, Cephaleuros is a derived monophyletic clade. Analysis of isolates of C. virescens, from the USA, Taiwan, and South Africa indicate that this taxon may consist of different species sharing a convergent morphology. The results of this study have implications for the taxonomy of the genera.     

Geographical and ecological distribution of marine halacarid genera and species (Acari: Halacaridae)

At the end of 2002, the number of marine halacarid species was 1018, that of genera 51. A single genus, Copidognathus contains 33% of all species (336). Eleven genera are monotypic. Geographical provinces with a large number of species are the tropical western Pacific, temperate northeastern Atlantic, temperate southeastern Pacific, and Mediterranean-Black Sea. Most records of halacarid species are from temperate and tropical areas; 10% of species are known from polar zones. On a generic level, 29 genera are recorded from tropical and temperate but not from polar provinces, five genera are restricted to the tropics, and none to polar regions. The majority (920 species or 90%) of all species live in the upper 200 m. Records of genera with exclusively algivorous or brackish/fresh water species are bound to littoral habitats; all the other genera occur in more than one depth zone. Arenicolous genera, though most abundant in the littoral zone, have representatives in the bathyal. Four marine genera (Copidognathus, Halacarellus, Isobactrus, Lohmannella) have representatives in coastal fresh water, and three genera, Acarothrix, Caspihalacarus and Peregrinacarus, are predominantly inhabitants of diluted brackish and fresh water. None of the free-living halacarid genera of the world's oceans appears to be endemic to one geographical province.