Phylogenetics of the marine sculpins (Teleostei: Cottidae) of the North American Pacific Coast

With 92 species along the North American Pacific Coast, marine sculpins represent the most species-rich radiation of fishes in this region. I used the mitochondrial cytochrome b gene and the nuclear ribosomal S7 intron for 99 species (76 North American, 19 Asian, and four North Atlantic) to produce the most complete phylogenetic hypothesis yet generated for this assemblage. Maximum likelihood and Bayesian analyses produced highly similar tree topologies. While many previously proposed groupings based on morphology are recovered, the molecular data suggest that a number of genera are para- or polyphyletic. However, this analysis supports the monophyly of one large clade that is found exclusively along the North American Pacific Coast (Chitonotous–Ruscarius–Artedius–Orthonopius–Clinocottus–Leiocottus–Oligocottus). Some sibling species have disjunct ranges, suggesting allopatric speciation. However, many other sibling species have largely overlapping ranges, and repeated habitat shifts appear to have facilitated diversification.     

Feeding patterns in eastern tropical Pacific blennioid fishes (Teleostei: Tripterygiidae,Labrisomidae, Chaenopsidae,Blenniidae)

Summary In terms of species number (47) and numerical abundance, blennioids are the most important primary resident rocky reef fishes in the Gulf of California, Mexico. We present the feeding patterns of the 34 most abundant species of blennioid fishes, 8 of which are Gulf endemics. A total of 2,144 specimens were sampled at 51 anaesthetic stations in 9 areas throughout the Gulf. Four feeding guilds were distinguished: 1) The majority (29 of 34 species) are microcarnivores exhibiting a number of different feeding strategies (ambush and stalking predators, active foragers, pickers, etc.). The more important prey categories were mobile invertebrates, and to some extent also sedentary fauna. Algae were of no importance for most of the latter species. 2) Hypsoblennius brevipinnis and H. gentilis are two omnivorous species, browsing mainly on sessile items including 52% and 13% (Vol.) algae in their diets. 3) Entomacrodus chiostictus and Ophioblennius steindachneri are herbivores, grazing on fine algae. 4) Plagiotremus azaleus specializes in cropping mucus and scales from the body surface of other fishes.Crustaceans account for 58.6% of the total volume of prey items in the 34 species investigated. Benthic amphipods were most important and made up 26% of the total volume of all prey items.Cluster analysis of percentage volumetric data using Squared Euclidian Distance and Horn's Index of Overlap produced distinct subgroups which coarsely reflected taxonomic grouping.The species are separated either by their geographic ranges, habitat and microhabitat preferences, feeding, or a combination thereof. Only rarely do sympatric species significantly overlap in diet.Trophic diversity as measured by the Shannon-index provides a tool for distinguishing: 1) specialists (6 species) from 2) low diversity feeders (18 species) and 3) high diversity generalists (10 species). Two different types of specialists can be distinguished: those which feed on the same items as the generalists but utilize only a very restricted prey spectrum (Stathmonotus sinuscalifornici and the chaenopsids Chaenopsis alepidota and Emblemaria hypacanthus). A second group of specialists (Entomacrodus chiostictus and Ophioblennius steindachneri as well as Plagiotremus azaleus) feed on items not utilized by any of the generalists.There is some evidence that high diversity generalists are numerically more abundant than the other trophic groups.In the labrisomids and blenniids a phylogenetic trend from microcarnivory towards feeding on sessile items appears to be expressed.     

Genetic assessment of species boundaries in the North American Daphnia longispina complex (Crustacea: Daphniidae)

Species boundaries in the North American Daphnia longispina group have proved difficult to establish on the basis of morphology alone. This confusion may be due to hydridization, phenotypic plasticity or the existence of sibling species. We therefore used genetic analysis to delineate species boundaries by examining 27 North American populations belonging to the longispina complex for variation at 15–26 allozyme loci. The populations consisted of Daphnia thorata from two western sites and two eastern sites, Daphnia galeata mendotae from its type location and seven sites across its range, and Daphnia rosea from eight temperate and seven arctic sites. Two populations from the Eurasian longispina complex were also included for reference. Populations assigned to D. galeata mendotae formed a genetically cohesive group, whereas a genetic dichotomy was found between temperate and arctic D. rosea , suggesting that this taxon includes two species. Genetic analysis also confirmed the distinctness of western D. thorata from other members of the longispina group. Unexpectedly, eastern populations resembling D. thorata were genetically more similar to temperate D. rosea than to any helmeted species ( D. galeata, Daphnia hyalina or D. thorata ). Our results suggest that the helmet character is a poor indicator of phylogenetic relationships, as the genetic ability to produce this feature has been lost or acquired several times in the evolution of the longispina group.     

Evidence of hybrid speciation in the North American primroses Primula suffrutescensP. parryiP. rusbyi and P. angustifolia (Primulaceae)

The genetic structure of tetraploid (4x = 44) North American species of Primula subgenus Auriculastrum: P. suffrutescens, P. parryi, P. rusbyi, and P. angustifolia was analyzed at seven enzyme loci and compared with that of the related diploid P. cuneifolia and P. nipponica. The studied tetraploid species showed fixed or almost fixed heterozygosity at various loci, indicating a hybrid origin. About half of their alleles were shared with Cuneifolia taxa sampled, suggesting that they arose from crosses involving a maternal Cuneifolia-like ancestor. A preliminary survey of their possible paternal species, as inferred from their genotypes, was carried out among different Primula groups. Several paternal alleles expected were observed in subgenus Aleuritia, particularly among taxa of sect. Crystallophlomis (e.g., P. chionantha, P. minor, and P. nivalis xanthobasis). However, none of these taxa proved to be a suitable paternal species. Hybridization events that originated P. suffrutescens, P. parryi, P. rusbyi, and P. angustifolia presumably occurred during Pleistocene secondary contacts in Beringia and involved a maternal Cuneifolia-like ancestor and at least two paternal species, for sect. Suffrutescens and Parryi, respectively. Further studies, involving a genetic survey of Aleuritia taxa from Siberia will be needed to detect such paternal species, if not extinct.     

Lack of genetic differentiation in the fat snook Centropomus parallelus (Teleostei: Centropomidae) along the Brazilian coast

The patterns of genetic variation in a fragment of the cytochrome b mtDNA gene in 130 individuals of the fat snook (Centropomus parallelus) did not show evidence of genetic differentiation along the Brazilian coast as shown in F‐statistics and AMOVA analyses, indicating the existence of high gene flow among the studied populations. In addition, the study of the evolutionary demography of the species using mismatch distribution analysis and statistical tests such as Tajima’s D and Fu’s F indicate that it experienced a pattern of population expansion during its recent evolutionary history.     

Biogeographical patterns of rocky intertidal communities along the Pacific coast of North America

Aim Our aim in this paper is to present the first broad‐scale quantification of species abundance for rocky intertidal communities along the Pacific coast of North America. Here we examine the community‐level marine biogeographical patterns in the context of formerly described biogeographical regions, and we evaluate the combined effects of geographical distance and environmental conditions on patterns of species similarity across this region. Location Pacific coast of North America. Methods Data on the percentage cover of benthic marine organisms were collected at 67 rocky intertidal sites from south‐eastern Alaska, USA, to central Baja California Sur, Mexico. Cluster analysis and non‐metric multidimensional scaling were used to evaluate the spatial patterns of species similarity among sites relative to those of previously defined biogeographical regions. Matrices of similarity in species composition among all sites were computed and analysed with respect to geographical distance and long‐term mean sea surface temperature (SST) as a measure of environmental conditions. Results We found a high degree of spatial structure in the similarity of intertidal communities along the coast. Cluster analysis identified 13 major community structure ‘groups’. Although breaks between clusters of sites generally occurred at major biogeographical boundaries, some of the larger biogeographical regions contained several clusters of sites that did not group according to spatial position or identifiable coastal features. Additionally, there were several outliers – sites that grouped alone or with sites outside their region – for which localized features may play an important role in driving community structure. Patterns of species similarity at the large scale were highly correlated with geographical distance among sites and with SST. Importantly, we found community similarity to be highly correlated with long‐term mean SST while controlling for the effects of geographical distance. Main conclusions These findings reveal a high degree of spatial structure in the similarity of rocky intertidal communities of the north‐east Pacific, and are generally consistent with those of previously described biogeographical regions, with some notable differences. Breaks in similarity among clusters are generally coincident with known biogeographical and oceanographic discontinuities. The strong correlations between species similarity and both geographical position and SST suggest that both geography and oceanographic conditions have a large influence on patterns of intertidal community structure along the Pacific coast of North America.     

Patterns of range-wide genetic variation in six North American bumble bee (Apidae: Bombus) species

The increasing evidence for population declines in bumble bee (Bombus) species worldwide has accelerated research efforts to explain losses in these important pollinators. In North America, a number of once widespread Bombus species have suffered serious reductions in range and abundance, although other species remain healthy. To examine whether declining and stable species exhibit different levels of genetic diversity or population fragmentation, we used microsatellite markers to genotype populations sampled across the geographic distributions of two declining (Bombus occidentalis and Bombus pensylvanicus) and four stable (Bombus bifarius; Bombus vosnesenskii; Bombus impatiens and Bombus bimaculatus) Bombus species. Populations of declining species generally have reduced levels of genetic diversity throughout their range compared to codistributed stable species. Genetic diversity can be affected by overall range size and degree of isolation of local populations, potentially confounding comparisons among species in some cases. We find no evidence for consistent differences in gene flow among stable and declining species, with all species exhibiting weak genetic differentiation over large distances (e.g. >1000 km). Populations on islands and at high elevations experience relatively strong genetic drift, suggesting that some conditions lead to genetic isolation in otherwise weakly differentiated species. B. occidentalis and B. bifarius exhibit stronger genetic differentiation than the other species, indicating greater phylogeographic structure consistent with their broader geographic distributions across topographically complex regions of western North America. Screening genetic diversity in North American Bombus should prove useful for identifying species that warrant monitoring, and developing management strategies that promote high levels of gene flow will be a key component in efforts to maintain healthy populations.     

Shellfish subsidies along the Pacific coast of North America

Spatial subsidies are associated with pronounced ecosystem responses, as nutrients cross ecological boundaries and cascade through food webs. While the importance of subsidies is known, the role of shellfish, specifically molluscs, as a marine subsidy has not been formally described. Focusing primarily on the Pacific coast of North America, we identify vectors that transport shellfish-derived nutrients into coastal terrestrial environments, including birds, mammals, and over 13 000 yr of marine resource use by people. Evidence from recipient ecosystems suggests shellfish drastically influence soil chemistry, forest productivity and the diversity of primary producers at the regional and landscape level. Responses in higher trophic levels have not yet been investigated, but given documented responses in lower trophic levels, this may be due to a lack of examination. To determine if the processes we describe within the northeast Pacific are pertinent to coastal environments worldwide, we also explore shellfish subsidies globally, with a specific focus on temperate and tropical islands. As shellfish are not as spatially or temporally constrained as other subsidies, our examination suggests our findings are applicable to many other geographical regions along the marine–terrestrial interface.     

Genetic variability in Chondrostoma from Austrian, French and Greek rivers (Teleostei, Cyprinidae)

Allozyme variation in Chondrostoma from Austrian, French and northern Greek rivers was investigated. Populations of C. nasus from the upper Danube catchment are genetically very similar and apparently connected by high level of gene flow. Chondrostoma nasus has conserved all major allozyme polymorphisms during its recent range expansion into the Rhone basin. Chondrostoma vardarense from the Axios and Aliakmonas rivers share most of their allozymes with C. nasus from the upper Danube catchment, but have less genetic variation, a possible consequence of a genetic bottleneck following river capture.     

BIODIVERSITY RESEARCH: Genetic diversity in two introduced biofouling amphipods (Ampithoe valida & Jassa marmorata) along the Pacific North American coast: investigation into molecular identification and cryptic diversity

Aim We investigated patterns of genetic diversity among invasive populations of Ampithoe valida and Jassa marmorata from the Pacific North American coast to assess the accuracy of morphological identification and determine whether or not cryptic diversity and multiple introductions contribute to the contemporary distribution of these species in the region. Location Native range: Atlantic North American coast; Invaded range: Pacific North American coast. Methods We assessed indices of genetic diversity based on DNA sequence data from the mitochondrial cytochrome c oxidase subunit I (COI) gene, determined the distribution of COI haplotypes among populations in both the invasive and putative native ranges of A. valida and J. marmorata and reconstructed phylogenetic relationships among COI haplotypes using both maximum parsimony and Bayesian approaches. Results Phylogenetic inference indicates that inaccurate species‐level identifications by morphological criteria are common among Jassa specimens. In addition, our data reveal the presence of three well supported but previously unrecognized clades of A. valida among specimens in the north‐eastern Pacific. Different species of Jassa and different genetic lineages of Ampithoe exhibit striking disparity in geographic distribution across the region as well as substantial differences in genetic diversity indices. Main conclusions Molecular genetic methods greatly improve the accuracy and resolution of identifications for invasive benthic marine amphipods at the species level and below. Our data suggest that multiple cryptic introductions of Ampithoe have occurred in the north‐eastern Pacific and highlight uncertainty regarding the origin and invasion histories of both Jassa and Ampithoe species. Additional morphological and genetic analyses are necessary to clarify the taxonomy and native biogeography of both amphipod genera.     

Effects of the East Australian Current on the genetic structure of a direct developing muricid snail (Bedeva hanleyi, Angas): variability within and among local populations

This paper examines the model that the East Australian Current (EAC) is an important determinant of genetic structure for the direct developing intertidal snail Bedeva hanleyi. Above latitude 33^o S on the east coast of Australia the EAC typically flows parallel to the shore in a southerly direction, whilst below 33^o S the direction of flow is predominantly offshore. Based on this flow-pattern it was predicted that B. hanleyi should exhibit greater genetic subdivision in the region south of 33^o S, due to smaller amounts of inter-population gene-flow via rafting. To test this hypothesis, collections of 45 individuals were made from each of 10–32 local populations/˜ 400 km region. Data for six polymorphic and apparently unlinked allozyme loci were consistent with the hypothesized effects of the EAC. Local populations from the northern region exhibited significantly more alleles per locus (mean = 2.2, cf. 1.8 for southern populations) and greater Hardy-Weinberg-expected heterozygosities (mean = 0.299, cf. 0.185 for southern populations) (one-tailed t -test; P <0.05 in each case). Moreover, the weighted jackknife ±mean SE) standardized genetic variance (θ) among southern populations (0.156 ± 0.025) was more than 50% higher than that among northern populations (0.103 ± 0.018).     

Vegetation formations and associations of the zonobiomes along the North American Pacific coast

This phytosociological study, carried out according to the Braun-Blanquet method and supported by cluster analysis, describes Walter's zonobiomes along the North American Pacific coast between British Columbia (Canada) and Baja California Sur (Mexico). Fourteen floristic associations have been identified and each is characterized by a unique floristic combination, a distinctive geographical range and particular bioclimatic conditions.Abbreviations of the associations that appear in table and figures AE Fraxino trifoliatae-Aesculetum parryi - AM Ambrosio chenopodifoliae-Larreetum tridentatae - BE Bergerocacto emoryi-Agavetum shawii - CA Calystegio intermediae-Ceanothetum megacarpi - CE Cercidio praecocis-Prosopidetum palmeri - CY Antigono leptopi-Cyrtocarpetum edulis - DU Malosmo laurinae-Quercetum dumosae - ID Agavo cerulatae-Idrietum columnaris - LO Lonicero denudatae-Quercetum agrifoliae - OX Oxalido oreganae-Sequoietum sempervirentis - RO Roso minutifoliae-Aesculetum parryi - TH Thujo plicatae-Tsugetum heterophyllae - UM Umbellulario californicae-Quercetum agrifoliae - YU Yucco validae-Fouquierietum diguetii     

Genetic population structure of the Dakota skipper (Lepidoptera: Hesperia dacotae): A North American native prairie obligate

A range-wide survey of Dakotaskipper (Hesperia dacotae) populationsassessed levels of genetic variability andgeographic scale of population structure inthis species of conservation concern. Thisspecies exists on isolated patches of nativetall- and mixed-grass prairie within a highlymodified landscape dominated by agriculture. It has been extirpated from the southernportion of its range and has sufferedrange-wide declines. Nine populations weresampled from western Minnesota, eastern SouthDakota, and southern Manitoba. Starch gelelectrophoresis was used to resolve 21 isozymeloci in 278 Dakota skippers. Dakota skipperpopulations were approximately as variable asother lepidopterans found in isolated habitats. Genetic distances indicated that Manitobapopulations were somewhat distinct from ones inMinnesota and South Dakota. Isolation-by-distance was detected range-wideand among the seven southern-most populations. Genetically effective immigration rates weresmall at both range-wide and regional scalesand effective populations sizes were lowsuggesting that Dakota skipper populations aregenetically isolated from one another, althoughthey were likely more connected in the recentpast. Genotype assignment tests revealed twoclusters of populations in Minnesota and SouthDakota that were not apparent from theisolation-by-distance results. Significantheterozygote deficiencies relative toHardy-Weinberg expectations and high inbreedingcoefficients suggest structure within samplelocations. Management recommendations includethe maximization of effective population sizein each Dakota skipper population to offset theeffects of drift and habitat corridors in somecases. Habitat management should consider thewithin-site population structure and possibletemporal population structure detected in thisstudy.     

Egg surface structure in the annual fishes Simpsonichthys (subgenera Ophthalmolebias and Xenurolebias) and Nematolebias (Teleostei: Cyprinodontiformes: Rivulidae): variability and phylogenetic significance

The surfaces of the egg chorion of nine species of Simpsonichthys , two of Nematolebias and eight other species of rivulids were studied with scanning electron microscopy revealing details of ornamentation that were previously undocumented. Surface structures of eggs of Simpsonichthys of the subgenus Ophthalmolebias are described for the first time: eggs of Simpsonichthys constanciae , Simpsonichthys perpendicularis , Simpsonichthys rosaceus and Simpsonichthys suzarti are ornamented with a very characteristic palm-like structure, that is restricted to these species among the rivulids examined. The surface of the egg chorion of Simpsonichthys bokermanni lacks the well-developed palm-like structure, but has a characteristic conical projection, distinct from the structures of other rivulids examined, that is proposed as homologous to the palm-like structure. Simpsonichthys bokermanni shares with Nematolebias papilliferus and Nematolebias whitei the presence of concentric rows of spiny projections around the micropylar region. Species of Simpsonichthys of the subgenus Ophthalmolebias , Simpsonichthys myersi (of the subgenus Xenurolebias ), and N. whitei share the presence of large rounded protuberances on the surface of the egg chorion. The phylogenetic significance of these features are evaluated and discussed in light of current knowledge about rivulid relationships.     

Low genetic diversity contrasts with high phenotypic variability in heptaploid Spartina densiflora populations invading the Pacific coast of North America

Species can respond to environmental pressures through genetic and epigenetic changes and through phenotypic plasticity, but few studies have evaluated the relationships between genetic differentiation and phenotypic plasticity of plant species along changing environmental conditions throughout wide latitudinal ranges. We studied inter‐ and intrapopulation genetic diversity (using simple sequence repeats and chloroplast DNA sequencing) and inter‐ and intrapopulation phenotypic variability of 33 plant traits (using field and common‐garden measurements) for five populations of the invasive cordgrass Spartina densiflora Brongn. along the Pacific coast of North America from San Francisco Bay to Vancouver Island. Studied populations showed very low genetic diversity, high levels of phenotypic variability when growing in contrasted environments and high intrapopulation phenotypic variability for many plant traits. This intrapopulation phenotypic variability was especially high, irrespective of environmental conditions, for those traits showing also high phenotypic plasticity. Within‐population variation represented 84% of the total genetic variation coinciding with certain individual plants keeping consistent responses for three plant traits (chlorophyll b and carotenoid contents, and dead shoot biomass) in the field and in common‐garden conditions. These populations have most likely undergone genetic bottleneck since their introduction from South America; multiple introductions are unknown but possible as the population from Vancouver Island was the most recent and one of the most genetically diverse. S. densiflora appears as a species that would not be very affected itself by climate change and sea‐level rise as it can disperse, establish, and acclimate to contrasted environments along wide latitudinal ranges.     

Pronounced genetic structure of mitochondrial DNA among populations of the circumglobally distributed grey mullet (Mugil cephalus)

Mitochondrial (ml) DNA genotypes of grey mullet ( Mugil cephalus ) from ocean basins around the world were analysed to estimate the amount of genetic differentiation in this cosmopolitan but mostly coastally-restricted species. Extensive genetic diversity was observed. Among 115 specimens from nine locales, 26 different haplotypes were detected using a battery of 13 restriction endonucleases. In phenetic analyses, these haplotypes grouped into seven distinct clusters whose members were in almost perfect accord with the geographic sources of the samples. Thus contemporary gene flow between the widespread collection locales must be absent or nearly so. Results contrast with the relative uniformity in mtDNA composition previously reported for populations of some circumglobally distributed pelagic fishes, and demonstrate that certain marine fishes with cosmopolitan distributions can exhibit pronounced population genetic structure even in the face of morphological conservatism.     

Taxonomic revision of the South American fish genus Chalceus Cuvier (Teleostei: Ostariophysi: Characiformes) with the description of three new species

The Neotropical characid fishes of the genus Chalceus Cuvier, 1817, are reviewed. In total, five species are recognized (including three new species). Chalceus epakros sp. nov. is the most widespread geographically, occurring in many rivers of the Amazon basin, the Río Orinoco and in the Essequibo River drainage in Guyana. Chalceus guaporensis sp. nov. is restricted to the upper Rio Madeira, Rio Guaporé and Río Madre de Dios, of Brazil, Bolivia and Peru, respectively. Chalceus spilogyros sp. nov. occurs only in the Rio Trombetas, lower Rio Tapajós and lower Rio Madeira drainages. Chalceus macrolepidotus Cuvier occurs in the Rio Negro drainage, middle and lower Río Orinoco basin and in the rivers of the Atlantic slopes of the Guianas, and Chalceus erythrurus Cope in the Rio Amazonas and Rio Solimões to Río Ucayali drainage in Peru. Chalceus ararapeera Cuvier & Valenciennes and Creagrutus pellegrini Puyo are considered synonyms of C. macrolepidotus , and Pellegrinina heterolepis Fowler is placed into the synonymy of C. erythrurus . Characters pertaining to the monophyly of Chalceus are discussed and a key to species is presented.  © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society , 2004, 140 , 103−135.     

Evaluating the effects of historic bottleneck events: an assessment of microsatellite variability in the endangered,North Atlantic right whale

Commercial exploitation reduced the North Atlantic right whale (Eubalaena glacialis) population from c. 12,000 in the 11th century to around 300 by the 21st century. We examine the effect of this population decline on levels of genetic variation at 16 microsatellite loci and contrast levels of variability to that in a closely related species (E. australis). Of the 13 loci developed from the E. glacialis genome, 100% were polymorphic in E. australis. In contrast, nine loci were polymorphic in E. glacialis and four were fixed. Both allelic diversity (A) and heterozygosity (H) were significantly lower in E. glacialis than E. australis (A = 3.2 +/- 2.6 vs. A= 6.9 +/- 3.3, P < 0.001; H= 0.31 +/- 0.25 vs. H= 0.72 +/- 0.23, P < 0.001, respectively). Bottleneck anlayses indicate that the population is in mutation-drift equilibrium and that a genetic bottleneck did not occur during the most recent decline (18th-20th centuries). Nevertheless, low frequency alleles are relatively uncommon in E. glacialis, suggesting that genetic variability has been reduced in this population. Possible origins of low genetic variability are discussed, including the slow but continual erosion of alleles during the 800-year period of decline.     

Structures and immunolocalization of Na+, K+ -ATPase, Na+ /H+ exchanger 3 and vacuolar-type H+ -ATPase in the gills of blennies (Teleostei: Blenniidae) inhabiting rocky intertidal areas

The structure and immunolocalization of the ion transporters Na(+) ,K(+) -ATPase (NKA), Na(+) /H(+) exchanger (NHE3) and vacuolar-type H(+) -ATPase (VHA) were examined in the gills of teleosts of the family Blenniidae, which inhabit rocky shores with vertical zonation in subtropical seas. These features were compared among the following species with different ecologies: the amphibious rockskipper blenny Andamia tetradactylus, the intertidal white-finned blenny Praealticus tanegasimae and the purely marine yaeyama blenny Ecsenius yaeyamaensis. Light and electron microscopic observations indicated that thick gill filaments were arranged close to each other and alternately on two hemibranches of a gill arch in the opercular space of A. tetradactylus. Many mucous cells (MC) and mitochondrion-rich cells (MRC) were present in the interlamellar regions of the gill filament. An immunohistochemical study demonstrated that numerous NKA, NHE3 and some VHA were located predominantly on presumed MRCs of gill filaments and at the base of the lamellae. Analyses using serial (mirror image) sections of the gills indicated that only a few NKA immunoreactive cells (IRC) were colocalized with VHA on some MRCs in the filaments. In the gills of P. tanegasimae, NKA- and NHE3-IRCs were observed in the interlamellar region of the filaments and at the base of the lamellae. VHA-IRCs were located sparsely on the lamellae and filaments. In the gills of E. yaeyamaensis, the lamellae and filaments were thin and straight, respectively. MCs were located at the tip as well as found scattered in the interlamellar region of gill filaments. NKA-, NHE3- and VHA-IRCs were moderately frequently observed in the filaments and rarely on the lamellae. This study shows that the structure and distribution of ion transporters in the gills differ among the three blennid species, presumably reflecting their different ecologies.