New records of two roughy fish species of Hoplostethus and a confirmed record of H.crassispinus Kotlyar, 1980 (Trachichthyiformes, Trachichthyidae) from Taiwan.

Two rarely caught species of the roughy fish genus Hoplostethus have been identified for the first time in the fish collections of Taiwan. The first, H.grandperrini Roberts & Gomon, 2012 was previously known only from two type specimens collected in the Southern Hemisphere off the coast of New Caledonia. Its distribution is now extended to the Northern Hemisphere off the coast of Pingtung, southern Taiwan. Our specimen represents the only record of this species since its initial description. The second, H.robustispinus Moore & Dodd, 2010 was originally described from a single specimen collected in the Philippines and was only known from the type locality and a single record off the Paracel Islands, South China Sea. This specimen represents the third record of the species since its original description. A single specimen of H.crassispinus Kotlyar, 1980, whose name has long appeared in the ichthyological literature of Taiwan and adjacent areas, was also identified as the first specimen-based record for Taiwan. Detailed descriptions of these species are provided and compared with available data of respective type specimens and related species, with intraspecific variations also discussed. Also included is a dichotomous key to all known species of the subgenus Hoplostethus in Taiwan.

Hoplostethus roseus, a new roughy fish from the western Pacific based on morphology and DNA barcoding (family Trachichthyidae).

A new species of the roughy fish genus Hoplostethus is described from 11 types and a non-type specimen collected from Taiwanese waters. It can be distinguished from its congeners by a combination of characters: pectoral-fin rays 14-17 (modally 15-16); pyloric caeca 65-84; total gill rakers 19-20; predorsal scales 18-22; oral cavity, branchial chamber, top and underside of tongue, and peritoneum uniformly black; distal margin of membrane between dorsal-fin spines black; caudal fin without a black margin; caudal-fin base brownish. Comparisons of the new species with similar species are provided. DNA barcoding supports the monophyly of the new species, which appears to be closely related to Hoplostethus japonicus [average cytochrome c oxidase subunit I Kimura-2-parameter (COI K2P) distance of 4.1%].

High migratory propensity constitutes a single stock of an exploited cutlassfish species in the Northwest Pacific: A microsatellite approach.

Cutlassfishes, also known as hairtails, include multiple predatory fishes of the family Trichiuridae. They constitute a top marine fish commodity globally, yet the knowledge about their composition and intraspecific genetic structures is still limited. Trichiurus japonicus accounts for a major amount in the northwest Pacific fishery. Previous studies based on mitochondrial DNA markers reported incongruences in its population structure, hence prompting the need for high-resolution markers and avoiding possible shortcomings in its management. Here we genotyped ten novel de novo-assembled transcriptome-derived microsatellite markers on a total of 150 samples across five major fishing grounds (encompassing latitudes 22-39°N). These markers presented a high number of alleles and heterozygosity compared to other marine fishes, corresponding to the large effective population size of ~20,000 per location and cohort differentiation. Population structuring analyses suggested T. japonicus to be a homogenous well-mixed population. This configuration is likely attributed to the majority of its effective population migrates across locations, and the absence of oceanographic barriers at the continental shelves. Qingdao with reportedly high ocean productivity could be a genetic pseudosink based on the high heterozygosity and migratory preference. Moreover, the results of sign tests suggest that T. japonicus experienced a recent bottleneck likely concurrent with historical glaciation events. Further, we demonstrated satisfactory cross-amplifications of our markers on several congeners, indicating a great promise to use these markers to study the population genetics of trichiurids. Together, our findings will serve as an essential groundwork for enhancing resource conservation and management of cutlassfishes.

A new cryptic species of the pineapple fish genus Monocentris (Family Monocentridae) from the western Pacific Ocean, with redescription of M. japonica (Houttuyn, 1782).

A new pineapple fish is described based on 26 type and 80 non-type specimens collected from Taiwan, Vanuatu, the Solomon Islands, and Queensland, Australia. This new species is sympatric with and similar to Monocentris japonica but can be distinguished from the latter in having only 6 or 7 scales on the third scale row below the lateral line; excisura notched and a small pseudo-excisura present on the sagittal otolith; consistently greater head depth, body depth, postorbital length, dorsal-fin-pelvic-fin length, and dorsal-fin-pectoral-fin length in proportion to standard length. A detailed description and designation of neotype are provided for M. japonica. DNA barcoding analysis supports the distinction of the new species with an estimated average COI gene divergence of 3.6 % from M. japonica.

Histology and transcriptomic analyses of barnacles with different base materials and habitats shed lights on the duplication and chemical diversification of barnacle cement proteins.

BACKGROUND: Barnacles are sessile crustaceans that attach to underwater surfaces using barnacle cement proteins. Barnacles have a calcareous or chitinous membranous base, and their substratum varies from biotic (e.g. corals/sponges) to abiotic surfaces. In this study, we tested the hypothesis that the cement protein (CP) composition and chemical properties of different species vary according to the attachment substrate and/or the basal structure. We examined the histological structure of cement glands and explored the variations in cement protein homologs of 12 barnacle species with different attachment habitats and base materials. RESULTS: Cement gland cells in the rocky shore barnacles Tetraclita japonica formosana and Amphibalanus amphitrite are eosinophilic, while others are basophilic. Transcriptome analyses recovered CP homologs from all species except the scleractinian coral barnacle Galkinia sp. A phylogenomic analysis based on sequences of CP homologs did not reflect a clear phylogenetic pattern in attachment substrates. In some species, certain CPs have a remarkable number of paralogous sequences, suggesting that major duplication events occurred in CP genes. The examined CPs across taxa show consistent bias toward particular sets of amino acid. However, the predicted isoelectric point (pI) and hydropathy are highly divergent. In some species, conserved regions are highly repetitive. CONCLUSIONS: Instead of developing specific cement proteins for different attachment substrata, barnacles attached to different substrata rely on a highly duplicated cementation genetic toolkit to generate paralogous CP sequences with diverse chemical and biochemical properties. This general CP cocktail might be the key genetic feature enabling barnacles to adapt to a wide variety of substrata.

Natural polyketide 6-pentyl-2H-pyrone-2-one and its synthetic analogues efficiently prevent marine biofouling.

Biofouling is a widespread phenomenon in oceans worldwide. With increasing human development and activities in open and coastal waters, and due to the environmental impact of AF organotins and copper-based paint, the demand for nontoxic antifouling (AF) paints is increasing. Various bioassays for antimicrobial activity, anti-biofilm formation and anti-barnacle settlement were established to evaluate the possibility of using marine natural products as AF agents. A series of natural products, isolated from the marine-derived fungi Trichoderma atroviride and T. reesei, were evaluated for their AF activity. One pyrone-type compound (1) demonstrated significant inhibitory activities toward barnacle cyprid settlement. Furthermore, a series of pyrone analogues (S1-S6) were synthesized, and their bioactivities were evaluated in the established systems. The results showed that compounds S5 and S6 exhibited a broad spectrum of bioactivities, such as anti-barnacle settlement, anti-biofilm formation and antimicrobial activities.

Variation in global distribution, population structures, and demographic history for four Trichiurus cutlassfishes.

BACKGROUND: Species-specific information on distribution and demographic patterns provides important implications for conservation and fisheries management. However, such information is often lacking for morphologically-similar species, which may lead to biases in the assessments of these species and even decrease effort towards sustainable management. Here, we aimed to uncover the distribution range, population structure and demographic history for four exploited Trichiurus cutlassfishes using genetics. These cutlassfishes contribute substantial global fisheries catch, with a high proportion of catch harvested from the NW Pacific. METHODS: We chose the widely available mitochondrial 16S ribosomal RNA (16S) as the genetic marker for cutlassfishes. We compiled the 16S sequence data from both the GenBank and a survey of trawler catch samples along the NW Pacific coasts 22-39°N. Genealogical relationships within each species was visualized with haplotype networks and potential population differentiations were further evaluated with AMOVA. Demographic histories were estimated using neutrality test, mismatch analysis, and the Bayesian skyline plot. The reconstructed phylogenetic trees were used to delimit and estimate the divergence time of species and included populations. RESULTS: In each of two cosmopolitan species, T. lepturus and T. nanhaiensis, we observed distinct populations along the coasts of warm oceans; such population differentiation might result from historical geographic barriers in the Pleistocene. In the NW Pacific, four Trichiurus species vary in their distribution habitats, which reflect differential ecological niches among these species. The small-sized T. brevis are primarily found in nearshore habitats; the warm-affiliated T. nanhaiensis are present along the path of the Kuroshio Current; the cold-affiliated T. japonicus spatially diverged from the widely-distributed T. lepturus, with the latter mainly occupy in warmer regions. Despite these differences, a single well-mixing fish stock, thus one management unit, was identified in each of the four species, presumably due to expansion of their population sizes predated the Last Glacial Maximum and a lack of distribution barrier. The most dominant T. japonicus, which have at least one magnitude higher effective population size than the others, show a unique abrupt size expansion event at 75 to 50-kilo years ago when the low sea level occurred during the ice age. MAIN CONCLUSIONS: The demographic history revealed by our genetic analyses advances understanding of the current distribution and population structure for these congeneric species. Moreover, the uncovered population structure provides insight into the assessment and management of these species. Such information complements contemporary knowledge about these species and enables us to forecast their ability to resist future environmental and anthropogenic disturbances.

Diverse Enzymes With Industrial Applications in Four Thraustochytrid Genera.

Thraustochytrids are heterotrophic fungus-like protists that can dissolve organic matters with enzymes. Four strains, AP45, ASP1, ASP2, and ASP4, were isolated from the coastal water of Taiwan, and respectively identified as Aurantiochytrium sp., Schizochytrium sp., Parietichytrium sp., and Botryochytrium sp. based on 18S rRNA sequences. Transcriptome datasets of these four strains at days 3-5 were generated using Next Generation Sequencing technology, and screened for enzymes with potential industrial applications. Functional annotations based on KEGG database suggest that many unigenes of all four strains were related to the pathways of industrial enzymes. Most of all four strains contained homologous genes for 15 out of the 17 targeted enzymes, and had extra- and/or intra-cellular enzymatic activities, including urease, asparaginase, lipase, glucosidase, alkaline phosphatase and protease. Complete amino sequences of the first-time identified L-asparaginase and phytase in thraustochytrids were retrieved, and respectively categorized to the Type I and BPPhy families based on phylogenetic relationships, protein structural modeling and active sites. Milligram quantities of highly purified, soluble protein of urease and L-asparaginase were successfully harvested and analyzed for recombinant enzymatic activities. These analytical results highlight the diverse enzymes for wide-range applications in thraustochytrids.

An Optimization-Based Locomotion Controller for Quadruped Robots Leveraging Cartesian Impedance Control.

Quadruped robots require compliance to handle unexpected external forces, such as impulsive contact forces from rough terrain, or from physical human-robot interaction. This paper presents a locomotion controller using Cartesian impedance control to coordinate tracking performance and desired compliance, along with Quadratic Programming (QP) to satisfy friction cone constraints, unilateral constraints, and torque limits. First, we resort to projected inverse-dynamics to derive an analytical control law of Cartesian impedance control for constrained and underactuated systems (typically a quadruped robot). Second, we formulate a QP to compute the optimal torques that are as close as possible to the desired values resulting from Cartesian impedance control while satisfying all of the physical constraints. When the desired motion torques lead to violation of physical constraints, the QP will result in a trade-off solution that sacrifices motion performance to ensure physical constraints. The proposed algorithm gives us more insight into the system that benefits from an analytical derivation and more efficient computation compared to hierarchical QP (HQP) controllers that typically require a solution of three QPs or more. Experiments applied on the ANYmal robot with various challenging terrains show the efficiency and performance of our controller.

Living with my small stomach: The experiences of post-bariatric surgery patients within 1 year after discharge.

AIMS AND OBJECTIVES: To explore how patients adapt to their changed body and life within the first year of receiving bariatric surgery. BACKGROUND: Bariatric surgery is used to treat severely obese patients. Most studies investigating the postsurgery period are about weight loss related issues. However, few studies have investigated these patients' subjective live experiences within the first year after discharge. DESIGN: A qualitative research using grounded theory method was applied. METHODS: In-depth interviews were conducted with 17 participants with a mean age of 34.5 years. The constant comparative method was used to analyse the interview data. FINDINGS: The core concept of "living with my small stomach" indicates that postbariatric patients are confronted with multidimensional challenges over time in their live experiences. Post-bariatric surgery patients felt "unexpected body discomforts" in the initial period after discharge. Qualitative analysis generated two different types of living processes-either in the "life modification" process or a "suffering" process. The associated categories and subcategories delineated the living process after discharge. In the life modification process, five categories were identified: "being forced to change meal habits," "bad feelings due to unsatisfied eating desires," "choosing food for quality rather than quantity," "persisting and confronting" and "getting support from family members." In the suffering process, three categories were identified: "health becoming worse due to loss of albumin," "suffering from bad health" and "emotional disturbances." Finally, most participants would engage in "valuing my changed body" by "doing the right things and maintaining my new life." CONCLUSIONS: How to modify one's life is the main concern of postbariatric patients. These patients need to either engage in the process of making life modifications or suffer from complications. RELEVANCE TO CLINICAL PRACTICE: Patients need support and health education regarding living with their small stomach. In addition, we should be more sensitive about the need to detect malabsorption early.

Description of five new coral associated Barnacles of the genus Trevathana (Balanomorpha: Pyrgomatidae) in Pacific Waters.

Five new species of coral inhabiting barnacles of the genus Trevathana (Balanomorpha: Pyrgomatidae), T. dongshaensis sp. nov., T. conica sp. nov., T. doni sp. nov., T. longidonta sp. nov. and T. taiwanus sp. nov., are described. These species are found in West Pacific waters including Japan, Taiwan (mainland and adjacent outlying islands including Dongsha Atoll) and Papua New Guinea. The species exhibit morphological differences in the scutum, the tergum, and cirri II and III, and form distinct clades in a phylogenetic tree based on DNA sequences of two genes, 12S rDNA and cytochrome C oxidase subunit I. Three of the five species, T. dongshaensis sp. nov., T. conica sp. nov. and T. taiwanus sp. nov., have relatively narrow distribution ranges and were recorded from the Dongsha Atoll (T. dongshaensis sp. nov. and T. conica sp. nov.) and the Taiwanese mainland (T. taiwanus sp. nov.). Trevathana longidonta sp. nov. and T. doni sp. nov. have wider distributions. Trevathana longidonta sp. nov. was collected from Japan, Taiwan and Dongsha Atoll and T. doni sp. nov. was collected from Taiwan, Dongsha Atoll and Papua New Guinea. In the waters of Japan, Taiwan and Dongsha Atoll, all the recorded Trevathana species inhabit corals of the family Merulinidae. However, in Papua New Guinea, T. doni sp. nov. is also recorded in the coral Oxypora, belonging to the family Lobophylliidae, and individuals living on Lobophyllidae and Merulinidae did not exhibit great variation in the divergence of the COI and 12S genes.

Phylogenetic relationships of Darwin's "Mr. Arthrobalanus": The burrowing barnacles (Cirripedia: Acrothoracica).

The barnacles of the superorder Acrothoracica are small, burrowing, epibiotic, and dioecious (large female with dwarf male) crustaceans largely found in the carbonate sediments and skeletons of marine invertebrates. The acrothoracicans represent the Cirripedia with the most plesiomorphic characters and have prominently featured in phylogenetic speculations concerning these crustaceans. Traditionally, Acrothoracica was divided into two main orders, Pygophora and Apygophora. The Apygophora had uniramus cirri and no anus. The Pygophora had biramus terminal cirri and an anus and was further divided into two families, Lithoglyptidae and Cryptophialidae. Kolbasov (2009) revised the superorder Acrothoracica on the basis of morphological examinations of females, dwarf males, and cyprids and rearranged the acrothoracican species into two new orders, Lithoglyptida and Cryptophialida. The present study is the first attempt to reconstruct the phylogenetic relationships of acrothoracican barnacles by sequencing two mitochondrial (cytochrome C oxidase I and 16S ribosomal DNA) and two nuclear (18S ribosomal DNA and histone H3) markers of 8 of the 11 genera comprising 23 acrothoracican species. All monophylies of the eight acrothoracican genera sampled in this study were strongly supported. The deep interfamilial relationship constructed is consistent with the recent morphological phylogenetic relationship proposed by Kolbasov, Newman, and Høeg (Kolbasov, 2009) that Cryptophialidae (order Cryptophialida) is the sister group to all other acrothoracicans (order Lithoglyptida). According to an ancestral character state reconstruction analysis, the posterior lobes of females; armament of opercular bars, attachment stalk, lateral projections of the body, and aperture slits in dwarf males; and habitat use appear to have phylogenetic importance.

Improved resolution and a novel phylogeny for the Neotropical triplefin blennies (Teleostei: Tripterygiidae).

The triplefin blennies (Teleostei: Tripterygiidae) are a diverse group of small-bodied benthic fishes associated with rocky or coral reefs. The Neotropics contain four genera and 26 species, many of which have only been recently described. A recent molecular phylogeny (Lin and Hastings, 2013) contrasts with previous phylogenies based on morphology in recovering the four Neotropical genera as a single clade with respect to the Indo-Pacific genera; however, relationships within and among genera were poorly resolved. This study reports a novel topology based on an expanded seven-loci molecular dataset. Individual gene trees have poor resolution, but concatenated analyses show strong support for most nodes, likely due to emergent support from concatenation. Consistent with Lin and Hastings (2013), three of the Neotropical genera, Axoclinus, Enneanectes, and Crocodilichthys, form a well-supported clade, but relationships of the fourth (Lepidonectes) are not confidently resolved. The monophyly of Axoclinus is well supported, but Enneanectes is paraphyletic with the inclusion of Axoclinus and Crocodilichthys. Improved resolution allows for reinterpretation of the biogeography of the Neotropical Tripterygiidae. Broader taxon sampling is still necessary for resolving the relationships within Tripterygiidae globally.

The complete mitochondrial genome of Poecilia formosa (Actinopterygii: Cyprinodontiformes: Poeciliidae).

The complete mitochondrial genome sequence of the Poecilia formosa is first reported in this study. The length of genome is 16 550 bp, including 13 protein-coding genes, 2 ribosomal RNA genes and 22 transfer RNA genes. Congeneric mitogenome sequence identity is 87.7% with P. reticulate and 93.1% with P. sphenops. The reconstructed phylogenetic relationships of 16 Cyprinodontiformes species based on 13 protein-coding genes were highly supported and the clade of all Poecilia fishes included had a support value of 100%. Our results shall provide a better understanding in the evolutionary histories of the Cyprinodontiformes.

The origins and evolution of dwarf males and habitat use in thoracican barnacles.

Barnacles are exceptional in having various sexual systems (androdioecy, hermaphroditism, dioecy) and with a high morphological diversity of males, though these are always minute (dwarf) compared to their female or hermaphrodite partners. For the first time, we use a multiple DNA marker-based phylogeny to elucidate the ancestral states and evolution of (1) dwarf males, (2) their morphology when present, (3) their attachment site on the partner, and (4) habitat use in thoracican barnacles. Our taxon sampling was especially rich in rare deep-sea Scalpelliformes and comprised species with diverse sexual systems and dwarf male morphologies. Within the thoracican barnacles dwarf male evolution is subject to extensive convergence, but always correlated to similar ecological conditions. Males evolved convergently at least four times from purely hermaphroditic ancestors, in each case correlated with the invasion into habitats with low mating group sizes. The independent evolution of dwarf males in these lineages dovetails with the males having different morphologies and occurring in several different locations on their sexual partner.

First study on gene expression of cement proteins and potential adhesion-related genes of a membranous-based barnacle as revealed from Next-Generation Sequencing technology.

This is the first study applying Next-Generation Sequencing (NGS) technology to survey the kinds, expression location, and pattern of adhesion-related genes in a membranous-based barnacle. A total of 77,528,326 and 59,244,468 raw sequence reads of total RNA were generated from the prosoma and the basis of Tetraclita japonica formosana, respectively. In addition, 55,441 and 67,774 genes were further assembled and analyzed. The combined sequence data from both body parts generates a total of 79,833 genes of which 47.7% were shared. Homologues of barnacle cement proteins - CP-19K, -52K, and -100K - were found and all were dominantly expressed at the basis where the cement gland complex is located. This is the main area where transcripts of cement proteins and other potential adhesion-related genes were detected. The absence of another common barnacle cement protein, CP-20K, in the adult transcriptome suggested a possible life-stage restricted gene function and/or a different mechanism in adhesion between membranous-based and calcareous-based barnacles.

Phylogeny and biogeography of a shallow water fish clade (Teleostei: Blenniiformes).

BACKGROUND: The Blenniiformes comprises six families, 151 genera and nearly 900 species of small teleost fishes closely associated with coastal benthic habitats. They provide an unparalleled opportunity for studying marine biogeography because they include the globally distributed families Tripterygiidae (triplefin blennies) and Blenniidae (combtooth blennies), the temperate Clinidae (kelp blennies), and three largely Neotropical families (Labrisomidae, Chaenopsidae, and Dactyloscopidae). However, interpretation of these distributional patterns has been hindered by largely unresolved inter-familial relationships and the lack of evidence of monophyly of the Labrisomidae. RESULTS: We explored the phylogenetic relationships of the Blenniiformes based on one mitochondrial (COI) and four nuclear (TMO-4C4, RAG1, Rhodopsin, and Histone H3) loci for 150 blenniiform species, and representative outgroups (Gobiesocidae, Opistognathidae and Grammatidae). According to the consensus of Bayesian Inference, Maximum Likelihood, and Maximum Parsimony analyses, the monophyly of the Blenniiformes and the Tripterygiidae, Blenniidae, Clinidae, and Dactyloscopidae is supported. The Tripterygiidae is the sister group of all other blennies, and the Blenniidae is the sister group of the remaining blennies. The monophyly of the Labrisomidae is supported with the exclusion of the Cryptotremini and inclusion of Stathmonotus, and we elevate two subgenera of Labrisomus to establish a monophyletic classification within the family. The monophyly of the Chaenopsidae is supported with the exclusion of Stathmonotus (placed in the Stathmonotini) and Neoclinus and Mccoskerichthys (placed in the Neoclinini). The origin of the Blenniiformes was estimated in the present-day IndoPacific region, corresponding to the Tethys Sea approximately 60.3 mya. A largely Neotropical lineage including the Labrisomidae, Chaenopsidae and Dactyloscopidae (node IV) evolved around 37.6 mya when the Neotropics were increasingly separated from the IndoPacific, but well before the closure of the Tethys Sea. CONCLUSIONS: Relationships recovered in this study are similar to those of earlier analyses within the Clinidae and Chaenopsidae, and partially similar within the Blenniidae, but tripterygiid relationships remain poorly resolved. We present the first comprehensive phylogenetic hypothesis for a monophyletic Labrisomidae with five tribes (Labrisomini, Mnierpini, Paraclinini, Stathmonotini and Starksiini). Global distributions of blenny genera included in our analysis support the evolution of a largely Neotropical clade whose closest relatives (clinids and cryptotremines) are temperate in distribution.

Description of a new species of coral-inhabiting barnacle, Darwiniella angularis sp. n. (Cirripedia, Pyrgomatidae) from Taiwan.

The present study has identified a new species from the previously monotypic genus Darwiniella Anderson, 1992. Darwiniella angularissp. n. is similar to Darwiniella conjugatum (Darwin, 1854) in external shell morphology and arthropodal characters. Darwiniella conjugatum, however, has a sharper tergal spur and a less obvious adductor plate angle when compared to Darwiniella angularissp. n. Molecular analyses on mitochondrial DNA 12S rDNA and COI regions also support the morphological differences. Sequence divergences in 12S rDNA and COI between Darwiniella conjugatum and Darwiniella angularissp. n. are 5% and 13% respectively, which are equivalent to the inter-specific sequence divergences in other barnacles. Both Darwiniella species are common on Cyphastrea Milne-Edwards and Haime, 1848 corals and Darwiniella angularissp. n. is also collected from Astreopora de Blainville, 1830 corals in Taiwan.

Evolution of a Neotropical marine fish lineage (Subfamily Chaenopsinae, Suborder Blennioidei) based on phylogenetic analysis of combined molecular and morphological data.

Phylogenetic relationships within tube blennies (Chaenopsinae) were reconstructed using Bayesian, maximum parsimony and likelihood analyses of multiple molecular markers (mitochondrial DNA: COI; nuclear DNA: TMO-4C4, RAG1, Rhodopsin, and Histone H3) and 148 morphological characters. This total-evidence based topology is well-resolved and congruent across analytical methods with strong support for the monophyly of the Chaenopsinae, all included genera and several internal nodes. A rapid radiation in the early evolution of chaenopsins is inferred from the relatively poor support values for relationships among basal lineages and their divergence into different habitats (rocky reefs, coral reefs and the reef/sand interface). Rates of molecular evolution in chaenopsins, as inferred by divergence among four putative transisthmian geminate species pairs, are rapid compared to other fishes. Conflicts among genetic markers and morphology are especially evident within the genus Coralliozetus, with different species relationships supported by morphology, TMO-4C4, and RAG1 plus Rhodopsin. This study hypothesizes a novel sistergroup relationship between Ekemblemaria and Hemiemblemaria, consistent with morphological, molecular and habitat use data. Our total evidence phylogenetic hypothesis indicates that previously hypothesized morphological characters supporting a close relationship between Hemiemblemaria and Chaenopsis plus Lucayablennius resulted from convergent evolution in these relatively free-swimming blennies.

Retinoic acid and Wnt/beta-catenin have complementary roles in anterior/posterior patterning embryos of the basal chordate amphioxus.

A role for Wnt/beta-catenin signaling in axial patterning has been demonstrated in animals as basal as cnidarians, while roles in axial patterning for retinoic acid (RA) probably evolved in the deuterostomes and may be chordate-specific. In vertebrates, these two pathways interact both directly and indirectly. To investigate the evolutionary origins of interactions between these two pathways, we manipulated Wnt/beta-catenin and RA signaling in the basal chordate amphioxus during the gastrula stage, which is the RA-sensitive period for anterior/posterior (A/P) patterning. The results show that Wnt/beta-catenin and RA signaling have distinctly different roles in patterning the A/P axis of the amphioxus gastrula. Wnt/beta-catenin specifies the identity of the ends of the embryo (high Wnt = posterior; low Wnt = anterior) but not intervening positions. Thus, upregulation of Wnt/beta-catenin signaling induces ectopic expression of posterior markers at the anterior tip of the embryo. In contrast, RA specifies position along the A/P axis, but not the identity of the ends of the embryo-increased RA signaling strongly affects the domains of Hox expression along the A/P axis but has little or no effect on the expression of either anterior or posterior markers. Although the two pathways may both influence such things as specification of neuronal identity, interactions between them in A/P patterning appear to be minimal.