The zoeal development of Platymaia wyvillethomsoni Miers, 1886 (Crustacea: Decapoda: Majoidea: Inachidae) described from laboratory reared material

The spider crab Platymaia wyvillethomsoni was reared in the laboratory, from hatching to the megalopal stage at 20°C. The larval development comprises two zoeal stages and a megalopa. The zoeal stages are described for the first time and compared with those of the four known species of the family Inachidae from the northern Pacific. The zoeal characters (carapace spines, antenna, mouthpart appendages, pleon and telson fork) of P. wyvillethomsoni are significantly different from those of two Achaeus species from northern Pacific and other inachid genera (Inachus and Macropodia) from the Atlantic. Therefore, this species should not be placed in the family Inachidae based on zoeal morphology. A provisional key for the identification of known zoeae of the family from the northern Pacific is provided.     

Growth of larval and juvenile Diaphus theta (Pisces: Myctophidae) in the transitional waters of the western North Pacific

Diaphus theta is one of the most common myctophid fish species in the subarctic and transitional waters of the North Pacific. The growth of larval and juvenile D. theta was investigated using sagittal otolith increment analysis of specimens caught in transitional waters of the western North Pacific. Samples taken over a 24-h period demonstrated that otoliths exhibited daily growth cycles, allowing accurate determination of age. Calcification of the incremental zone of otoliths took place only at night, suggesting that the formation cycle of the increment of juvenile D. theta was different from that of shallow-water fishes and would be related to their diel vertical migration. The relationships between standard length (SL) and daily growth increment (D) were expressed as linear equations: SL = 2.65 + 0.141D (r ² = 0.942) for larvae of 5.1–9.6 mm SL and SL = 3.54 + 0.129D (r ² = 0.933) for juveniles of 13.7–27.6 mm SL. The growth rates were 0.14 mm d⁻¹ in larvae and 0.13 mm d⁻¹ in juveniles; this is slow compared with tropical or subtropical mycto-phid species, in which growth occurs at about twice these rates. The larval period, including the metamorphic stage, was long compared with species at lower latitudes and was estimated to be 71 days. The slow growth rate and long period of larval stage of D. theta would be the life history pattern of high-latitudinal species adapted to a low-temperature habitat. Received: March 23, 2001 / Revised: July 5, 2001 / Accepted: July 19, 2001     

Larval development of bigmouth manefish Caristius macropus (Perciformes: Caristiidae) from the western North Pacific

Larvae of bigmouth manefish Caristius macropus are described and illustrated on the basis of seven specimens (4.2–10.5 mm in body length) from the Kuroshio waters (0–60 m depth) and the transition waters (surface) between the Kuroshio and Oyashio fronts of the western North Pacific. The present larvae of C. macropus are distinguished from those of Paracaristius maderensis that inhabit the North Pacific by having 39–40 myomeres, 34 dorsal-fin rays, and 22 anal-fin rays. The present study, along with previous studies of the early life stages of caristiids, shows that larvae of the family may be defined by the following characters: body elongate in preflexion stage but becoming deep bodied and hatchet shaped after notochord flexion; anus located near vertical through base of pectoral fin; head large, without spination or serration; a distinct vertical band on the posterior tail throughout the larval stages, and two bands gradually appearing on the tail and trunk during the flexion and postflexion stages; and melanophores present around the notochord tip by the flexion stage. Adult C. macropus are found in the subarctic and temperate waters of the North Pacific; however, the present study and other occurrences of early life stages of the species probably indicate that C. macropus may spawn over a wide area in the North Pacific.     

Patterns of genetic diversity of the cryptogenic red alga Polysiphonia morrowii (Ceramiales,Rhodophyta) suggest multiple origins of the Atlantic populations

The red alga Polysiphonia morrowii, native to the North Pacific (Northeast Asia), has recently been reported worldwide. To determine the origin of the French and Argentine populations of this introduced species, we compared samples from these two areas with samples collected in Korea and at Hakodate, Japan, the type locality of the species. Combined analyses of chloroplastic (rbcL) and mitochondrial (cox1) DNA revealed that the French and Argentine populations are closely related and differ substantially from the Korean and Japanese populations. The genetic structure of P. morrowii populations from South Atlantic and North Atlantic, which showed high haplotype diversity compared with populations from the North Pacific, suggested the occurrence of multiple introduction events from areas outside of the so‐called native regions. Although similar, the French and Argentine populations are not genetically identical. Thus, the genetic structure of these two introduced areas may have been modified by cryptic and recurrent introduction events directly from Asia or from other introduced areas that act as introduction relays. In addition, the large number of private cytoplasmic types identified in the two introduced regions strongly suggests that local populations of P. morrowii existed before the recent detection of these invasions. Our results suggest that the most likely scenario is that the source population(s) of the French and Argentine populations was not located only in the North Pacific and/or that P. morrowii is a cryptogenic species.     

The evolution of mating systems in a group of brooding sea anemones (Epiactis)

Summary

The sea anemone genus Epiactis provides an unusually good opportunity to study the evolution of brooding and mating systems. The four Epiactis species on the Pacific coast of North America all brood their offspring up to the juvenile stage, but each has a different combination of internal vs. external brooding and gonochory vs. simultaneous or gynodioecious hermaphroditism. Two of the four species (E. prolifera and E. lisbethae) were indistinguishable with allozymes (20 loci), but could be differentiated using multilocus DNA fingerprinting. Phylogenetic analyses of the allozyme data by distance and parsimony methods using three outgroups suggest that the four nominal Epiactis species are polyphyletic, with the two internal brooders evolving independently of the two external brooders. This topology does not allow inferences about the evolutionary order of hermaphroditism, dioecy and gynodioecy. Separate sexes and obligate outcrossing are of ten believed to be ancestral, with hermaphroditism and the potential for self-fertilization being favored in taxa where restricted dispersal promotes inbreeding. Previous studies of population genetic structure in these Epiactis species is consistent with this hypothesis, as even the cross-fertile species were highly inbred.     

Intraspecific sterility barrier confirms that introduction of Sphaerotrichia divaricata (Phaeophyceae,Chordariales) into the Mediterranean was from Japan

Crossing studies revealed an intraspecific sterility barrier on the level of zygote formation between Japanese Sphaerotrichia divaricata and isolates of the same species from the Northeast Pacific and the North Atlantic. Because no consistent morphological differences exist between sporophytes from Japan and other areas, we propose not to distinguish the intersterile populations as different species. Japanese Sphaerotrichia and isolates from a recently detected population in the Étang de Thau, French Mediterranean coast, are interfertile. The crossing studies support the assumption that this Mediterranean population is a recent introduction from Japan.     

Diversity and distribution of foliose Bangiales (Rhodophyta) in West Greenland: a link between the North Atlantic and North Pacific

Greenland is a continental island in the northern part of the North Atlantic where the foliose Bangiales flora is poorly known. It is an important area for the study of algal biogeography because of the region’s glacial history, in which Greenland has been alternately exposed to or isolated from the North Pacific via the Bering Strait. A molecular study using 3′ rbcL + 5′ rbcL–S sequences was undertaken to assess the diversity of foliose Bangiales on the west coast of Greenland and rbcL sequences were used to study the Greenland flora in a larger phylogenetic and floristic context. New and historic collections document seven species in four genera from the west coast of Greenland. All species had a close link to North Pacific species, being either conspecific with them or North Atlantic–North Pacific vicariant counterparts.     

An analysis of competitive interactions between 3 hermit crab species

Summary Competition for empty gastropod shells in a group of three sympatric hermit crabs (Pagurus hirsutiusculus, Pagurus granosimanus, and Pagurus beringanus) was studied in the San Juan Archipelago, Washington State. Estimates of the competitive effects of each species on the others' shell supplies were derived using field data on shell utilization and the results of laboratory experiments to determine rates of acquisition and exchange of shells and preferences for different shell species. Each species experienced approximately an order of magnitude more intraspecific competition than interspecific competition for empty shells. This resulted from differences in preference for shell shapes, shell size use, and habitat use between P. hirsutiusculus and P. granosimanus, and largely from differences in habitat use between P. beringanus and the other two species. Experiments involving the release and recensusing of marked empty shells were used to estimate competitive effects more directly for the interaction between P. hirsutiusculus and P. granosimanus. Results were consistent with the estimates derived from data on resource partitioning. Possible causes of the low levels of interspecific competition are discussed, and results are compared with studies of other organisms that estimated both inter- and intra-specific competition.     

Redescription of a rare deep-sea batfish, <Emphasis Type="Italic">Halieutopsis bathyoreos</Emphasis> (Lophiiformes: Ogcocephalidae)

Halieutopsis bathyoreos Bradbury, 1988 (Lophiiformes: Ogcocephalidae), previously described only on the basis of the holotype (62.6mm in standard length) from the central North Pacific, is redescribed on the basis of the holotype and six additional specimens (41.2–68.7mm in standard length) collected from the western South Pacific, off Papua New Guinea, and the western North Pacific, including the Japanese Archipelago. Halieutopsis bathyoreos is distinguished from its congeners by having a shelflike rostrum extending anteriorly well beyond the mouth, a dorsal escal lobe slightly bisected ventrally, an illicial cavity square in outline and completely visible in ventral view, and lacking tubercles on the ventral surface of the disk. The following characters are newly added to the diagnoses of this species: rostrum width 21–29% of head length, tubercles on the dorsal surface of the disk about half the diameter of those on the lateral margin, and 13–15 large lateral-line scales on the tail.     

An introduced population of Chorda asiatica (Chordaceae,Laminariales) in Puget Sound,Pacific coast of North America

Northeastern Pacific Ocean and northwestern Atlantic Ocean populations of Chorda species, which have not been examined in previous phylogenetic studies, were investigated. All specimens that were collected in Hood Canal, Puget Sound, WA, USA, Pacific coast of North America, showed identical ITS‐5.8S rDNA sequences, and they were included in the clade of Japanese Chorda asiatica. With morphological data added to the molecular data, they were identified as C. asiatica and were concluded to be non‐indigenous populations, most likely introduced with oyster spat together with Sargassum muticum. Specimens collected in New York, NY, USA, Atlantic coast of North America, were genetically closest to C. filum from Newfoundland and were identified as C. filum. The genetic divergence of the North Atlantic populations of C. filum was relatively small compared to that of Japanese C. asiatica considering their broader distributional ranges on both sides of the Atlantic.     

PORPHYRA REDIVIVA SP. NOV. (RHODOPHYTA): A NEW SPECIES FROM NORTHEAST PACIFIC SALT MARSHES1

A new species, Porphyra rediviva (Bangiales, Rhodophyta), is described from the northeast Pacific based on morphological, cytological, reproductive, ecological, and molecular characters. This species occurs at high intertidal levels in salt marshes along the coasts of Washington, Oregon, and northern California and exhibits a growth optimum at reduced salinity. It is further distinguished by a distinct demarcation between male and female sectors of the gametophytic thalli of epilithic specimens. The species is found most commonly in the drift or trapped in Salicornia beds, but these detached blades never have been found with sporangia or gametangia. Molecular analyses using restriction fragment length polymorphism patterns of polymerase chain reaction–amplified ribosomal DNA (rDNA) show that this salt marsh Porphyra is conspecific throughout its range and is distinct from other Pacific Porphyra species with similar reproductive patterns. Based on molecular data, P. rediviva is related most closely to P. purpurea from the North Atlantic. Fixed rDNA polymorphisms between the two taxa, however, support ecological and cytological evidence that they should be considered different species.     

Trans‐Pacific and trans‐Arctic pathways of the intertidal macroalga Fucus distichus L. reveal multiple glacial refugia and colonizations from the North Pacific to the North Atlantic

Aim We examined the phylogeography of the cold‐temperate macroalgal species Fucus distichus L., a key foundation species in rocky intertidal shores and the only Fucus species to occur naturally in both the North Pacific and the North Atlantic. Location North Pacific and North Atlantic oceans (42° to 77° N). Methods We genotyped individuals from 23 populations for a mitochondrial DNA (mtDNA) intergenic spacer (IGS) (n = 608) and the cytochrome c oxidase subunit I (COI) region (n = 276), as well as for six nuclear microsatellite loci (n = 592). Phylogeographic structure and connectivity were assessed using population genetic and phylogenetic network analyses. Results IGS mtDNA haplotype diversity was highest in the North Pacific, and divergence between Pacific haplotypes was much older than that of the single cluster of Atlantic haplotypes. Two ancestral Pacific IGS/COI clusters led to a widespread Atlantic cluster. High mtDNA and microsatellite diversities were observed in Prince William Sound, Alaska, 11 years after severe disturbance by the 1989 Exxon Valdez oil spill. Main conclusions At least two colonizations occurred from the older North Pacific populations to the North Atlantic between the opening of the Bering Strait and the onset of the Last Glacial Maximum. One colonization event was from the Japanese Archipelago/eastern Aleutians, and a second was from the Alaskan mainland around the Gulf of Alaska. Japanese populations probably arose from a single recolonization event from the eastern Aleutian Islands before the North Pacific–North Atlantic colonization. In the North Atlantic, the Last Glacial Maximum forced the species into at least two known glacial refugia: the Nova Scotia/Newfoundland (Canada) region and Andøya (northern Norway). The presence of two private haplotypes in the central Atlantic suggests the possibility of colonization from other refugia that are now too warm to support F. distichus. With the continuing decline in Arctic ice cover as a result of global climate change, renewed contact between North Pacific and North Atlantic populations of Fucus species is expected.     

AN ATLANTIC POPULATION OF PIKEA CALIFORNICA (DUMONTIACEAE,RHODOPHYTA)1

The marine red alga Pikea californica Harvey, previously known only from the east coast of Japan and the west coast of North America, was found in 1983 to be abundant in the surge zone throughout the Isles of Scilly archipelago, off SW England. Examination of herbarium material showed that the population was present in 1967. All plants observed in July 1983 and September 1984 were sterile, but reproductive male and female plants were collected in November 1983. The habitat and phenology of P. californica in the Isles of Scilly closely resemble those of Pacific populations. English plants are vegetatively and reproductively identical to the type and other California specimens. They can easily be distinguished from Sphaerococcus coronopifolius Stackhouse (Sphaerococcaceae, Gigartinales), the most similar species in the flora of the British Isles, by the presence in transverse sections of several lacunae, representing axial and whorl-branchlet filaments, in contrast to the single axial filament of S. coronopifolius. It is possible that the Isles of Scilly population of P. californica is a relict of a species once more widespread, but it seems more likely that it is another example of the well-established pattern of marine introductions into the British Isles from the North Pacific. The range of temperature regimes occupied by P. Californica in the Pacific suggests that the species could become more widespread in Europe, but at present it appears to be confined to the Isles of Scilly.     

THE GENUS PIKEA (DUMONTIACEAE,RHODOPHYTA) IN ENGLAND AND THE NORTH PACIFIC: COMPARATIVE MORPHOLOGICAL,LIFE HISTORY,AND MOLECULAR STUDIES1

A Pikea species attributed to Pikea californica Harvey has been established in England since at least 1967. Previously, this species was believed to occur only in Japan and Pacific North America. Comparative morphological studies on field-collected material and cultured isolates from England, California, and Japan and analysis of organellar DNA restriction fragment length polymorphisms, detected using labeled organellar DNA as a non-radioactive probe, showed that English Pikea is conspecific with P. californica from California. Both populations consist of dioecious gametophytes with heteromorphic life histories involving crustose tetrasporophytes; 96% of organellar DNA bands were shared between interoceanic samples. A second dioecious species of Pikea, P. pinnata Setchell in Collins, Holden et Setchell, grows sympatrically with P. californica near San Francisco but can be distinguished by softer texture, more regular branching pattern, and elongate cystocarpic axes. Pikea pinnata and P. californica samples shared 49–50% of organellar DNA bands, consistent with their being distinct species. Herbarium specimens of P. robusta Abbott resemble P. pinnata in some morphological features but axes are much wider; P. robusta may represent a further, strictly sub-tidal species but fertile material is unknown. Pikea thalli from Japan, previously attributed to P. californica and described here as Pikea yoshizakii sp. nov., are monoecious and show a strikingly different type of life history. After fertilization, gonimoblast filaments grow outward through the cortex and form tetrasporangial nemathecia; released tetraspores develop directly into erect thalli. Tetrasporoblastic life histories are characteristic of certain members of the Phyllophoraceae but were previously unknown in the Dumontiaceae. Japanese P. yoshizakii shared 55 and 56% of organellar DNA bands with P. californica and P. pinnata, respectively; phylogenetic analysis indicated equally distant relationships to both species. Pikea yoshizakii or a closely similar species with the same life history occurs in southern California and Mexico.     

Distribution and species composition of juvenile and adult scombropids (Teleostei,Scombropidae) in Japanese coastal waters

Two scombropid fishes, Scombrops boops and Scombrops gilberti, are closely related and commercially important species in Japan. These species are often confused in commercial markets because of their morphological similarity. In this study, scombropid specimens collected from various Japanese coastal waters were subjected to polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) analysis and phylogenetic analysis of the 16S rRNA gene in mitochondrial DNA. These analyses showed that all the scombropid specimens collected from localities in the Sea of Japan were identified as S. boops, whereas those from the Pacific Ocean included two species, S. boops and S. gilberti. Almost all juvenile (<200 mm standard body length, S_L) S. gilberti originated from the Pacific coastal waters of the northern Japan, whereas adults (>400 mm S_L) were found only in deep water off the Izu Peninsula to the Izu Islands. This suggests that S. gilberti might migrate extensively during its life cycle. In addition, differences in the number of specimens and the distribution between the two species suggest that S. gilberti is less abundant than S. boops in Japanese waters.     

Diversity of Chroothece (Rhodophyta,Stylonematales) including two new species

Chroothece has been reported from a range of freshwater environments, including streams, shallow ponds, trickling water on cliffs and moist soils, mostly in Europe and North America. The identification of genera and species by morphology is difficult because of overlaps in critical characters. To help clarify diversity within the genus, samples from Spain and from other regions (UK and Guam, western Pacific) were compared. Ecological and morphological data from field and cultured material were correlated with molecular data (rbcL gene sequences) that differentiate two new species: Chroothece thermalis I. Chapuis, P. Sánchez, M. Aboal & O. Necchi Jr., sp. nov. in a thermal spring and Chroothece lobata M. Aboal, B. A. Whitton, I. Chapuis, P. Sánchez & O. Necchi Jr., sp. nov. in a semi-arid stream. The results suggest recognition of four species, C. thermalis, C. lobata, C. richteriana Hansgirg and C. rupestris Hansgirg, from Spain. Morphology and ecology are useful to help distinguish these species, but the genus needs further study for possible cryptic diversity.     

Three gene phylogeny of the Thoreales (Rhodophyta) reveals high species diversity

The freshwater red algal order Thoreales has triphasic life history composed of a diminutive diploid “Chantransia” stage, a distinctive macroscopic gametophyte with multi‐axial growth and carposporophytes that develop on the gametophyte thallus. This order is comprised of two genera, Thorea and Nemalionopsis. Thorea has been widely reported with numerous species, whereas Nemalionopsis has been more rarely observed with only a few species described. DNA sequences from three loci (rbcL, cox1, and LSU) were used to examine the phylogenetic affinity of specimens collected from geographically distant locations including North America, South America, Europe, Pacific Islands, Southeast Asia, China, and India. Sixteen species of Thorea and two species of Nemalionopsis were recognized. Morphological observations confirmed the distinctness of the two genera and also provided some characters to distinguish species. However, many of the collections were in “Chantransia” stage rather than gametophyte stage, meaning that key diagnostic morphological characters were unavailable. Three new species are proposed primarily based on the DNA sequence data generated in this study, Thorea kokosinga‐pueschelii, T. mauitukitukii, and T. quisqueyana. In addition to these newly described species, one DNA sequence from GenBank was not closely associated with other Thorea clades and may represent further diversity in the genus. Two species in Nemalionopsis are recognized, N. shawii and N. parkeri nom. et stat. nov. Thorea harbors more diversity than had been recognized by morphological data alone. Distribution data indicated that Nemalionopsis is common in the Pacific region, whereas Thorea is more globally distributed. Most species of Thorea have a regional distribution, but Thorea hispida appears to be cosmopolitan.     

Pselaphotumulus,a new genus of pselaphine endemic to New Zealand (Coleoptera: Staphylinidae: Pselaphinae: Pselaphitae)

ABSTRACT

Pselaphotumulus Owens and Carlton, gen. nov., is described as the sixth genus in the tribe Pselaphini known from New Zealand. Three new species are described: Pselaphotumulus aorerei, sp. nov., Pselaphotumulus dubius, sp. nov. and Pselaphotumulus unus, sp. nov.. Three species, Pselaphus cavelli (Broun 1893), Pselaphus oviceps (Broun 1917) and Pselaphus urquharti (Broun 1917) are transferred to Pselaphotumulus, nov. combs. Lectotypes from type series in the New Zealand Broun Collection (Natural History Museum, London) are designated for these three species. Habitus photographs, distributional maps and line drawings of diagnostic characters are provided for each species. A key to species is provided. Searches of museum collections have not yielded representatives outside of New Zealand, suggesting that this is the first endemic genus in the tribe Pselaphini described from the New Zealand’s main islands, specifically, the South Island. Pselaphotumulus species exhibit restricted distribution patterns that approximately coincide with the Pacific/Indo Australian Plate boundary.