Two new species of Parahesione (Annelida: Hesionidae) associated with ghost shrimps (Crustacea: Decapoda) and their phylogenetic relationships

Two new species of Hesionidae, Parahesione pulvinata sp. nov. and Parahesione apiculata sp. nov. are described based on materials collected at tidal flats in Okinawa (Japan) from burrows of the ghost shrimps Neocallichirus jousseaumei and Glypturus armatus. The two new species are characterized by having eight enlarged cirri, dorsal cirrophores with dorsal foliose lobe and biramous parapodia, and by lacking median antenna. Parahesione apiculata sp. nov. has digitate lobes on the posterior margin of the dorsal foliose lobe (absent in P. pulvinata sp. nov.). The two new species were never found outside the ghost shrimp burrows, suggesting they are obligate symbionts. Phylogenetic analyses based on four concatenated genes suggest that the symbiotic lifestyle has evolved several times in Hesionidae.

Synonymization of two, monotypic black-coral-commensal scale worm genera, Antipathipolyeunoa Pettibone, 1991 and Parahololepidella Pettibone, 1969 (Polynoidae, Aphroditiformia)

Parahololepidella Pettibone, 1969 is a polynoid genus commensal with the antipatharian genus Tanacetipathes Opresko, 2001. These scale worms are elongate with numerous segments and small elytra. To date, the only other known polynoid associated with Tanacetipathes is Antipathipolyeunoa Pettibone, 1991. By re-examining the holotype of Antipathipolyeunoa, we have identified several overlooked characters that no longer distinguish this genus from Parahololepidella. Based on the presence of chaetae on the tentacular segment and elytral irregularity on posterior segments, we propose synonymizing Antipathipolyeunoa with Parahololepidella.

A transcriptome-based phylogeny for Polynoidae (Annelida: Aphroditiformia)

Polynoidae is the most diverse radiation of Aphroditiformia and one of the most successful groups of all Annelida in terms of diversity and habitats colonized. With such an unmatched diversity, phylogenetic investigations have struggled to understand their evolutionary relationships. Previous phylogenetic analyses have slowly increased taxon sampling and employed methodologies, but despite their diversity and biological importance, large genomic sampling is limited. To investigate the internal relationships within Polynoidae, we conducted the first phylogenomic analyses of the group based on 12 transcriptomes collected from species inhabiting a broad array of habitats, including shallow and deep waters, as well as hydrothermal vents, anchialine caves and the midwater. Our phylogenomic analyses of Polynoidae recovered congruent tree topologies representing the clades Polynoinae, Macellicephalinae and Lepidonotopodinae. Members of Polynoinae and Macellicephalinae clustered in well supported and independent clades. In contrast, Lepidonotopodinae taxa were always recovered nested within Macellicephalinae. Though our sampling only covers a small proportion of the species known for Polynoidae, our results provide a robust phylogenomic framework to build from, emphasizing previously hypothesized relationships between Macellicephalinae and Lepidonotopodinae taxa, while providing new insights on the origin of enigmatic cave and pelagic lineages.

An integrative re-evaluation of Typhlatya shrimp within the karst aquifer of the Yucatán Peninsula, Mexico

The Yucatán Peninsula, Mexico is a carbonate platform well-known for extensive karst networks of densely stratified aquifer ecosystems. This aquifer supports diverse anchialine fauna, including species of the globally distributed anchialine shrimp genus Typhlatya (Atyidae). Four species (T. campecheae, T. pearsei, T. dzilamensis and T. mitchelli) are endemic to the Peninsula, of which three are federally listed in Mexico. This first integrative evaluation (i.e., molecular, morphological, broad geographic and type locality sampling, and environmental data) of Yucatán Typhlatya reveals considerable species identity conflict in prior phylogenetic assessments, broad species ranges, syntopy within cave systems and five genetic lineages (of which two are new to science). Despite sampling from the type locality of endangered T. campecheae, specimens (and molecular data) were indistinguishable from vulnerable T. pearsei. Ancestral/divergence reconstructions support convergent evolution of a low-salinity ancestor for a post-Paleogene arc Yucatán + Cuba Typhlatya clade within the anchialine Atyidae clade. A secondary adaptation for the coastal-restricted euryhaline (2–37 psu), Typhlatya dzilamensis (unknown conservation status) was identified, while remaining species lineages were low-salinity (< 5 psu) adapted and found within the meteoric lens of inland and coastal caves. This study demonstrates the need for integrative/interdisciplinary approaches when conducting biodiversity assessments in complex and poorly studied aquifers.

Muscular adaptations in swimming scale worms (Polynoidae, Annelida)

Annelids are predominantly found along with the seafloor, but over time have colonized a vast diversity of habitats, such as the water column, where different modes of locomotion are necessary. Yet, little is known about their potential muscular adaptation to the continuous swimming behaviour required in the water column. The musculature and motility were examined for five scale worm species of Polynoidae (Aphroditiformia, Annelida) found in shallow waters, deep sea or caves and which exhibit crawling, occasional swimming or continuous swimming, respectively. Their parapodial musculature was reconstructed using microCT and computational three-dimensional analyses, and the muscular functions were interpreted from video recordings of their locomotion. Since most benthic scale worms are able to swim for short distances using body and parapodial muscle movements, suitable musculature for swimming is already present. Our results indicate that rather than rearrangements or addition of muscles, a shift to a pelagic lifestyle is mainly accompanied by structural loss of muscle bundles and density, as well as elongation of extrinsic dorsal and ventral parapodial muscles. Our study documents clear differences in locomotion and musculature among closely related annelids with different lifestyles as well as points to myoanatomical adaptations for accessing the water column.

Morphological convergence and adaptation in cave and pelagic scale worms (Polynoidae, Annelida)

Across Annelida, accessing the water column drives morphological and lifestyle modifications-yet in the primarily "benthic" scale worms, the ecological significance of swimming has largely been ignored. We investigated genetic, morphological and behavioural adaptations associated with swimming across Polynoidae, using mitogenomics and comparative methods. Mitochondrial genomes from cave and pelagic polynoids were highly similar, with non-significant rearrangements only present in cave Gesiella. Gene orders of the new mitogenomes were highly similar to shallow water species, suggestive of an underlying polynoid ground pattern. Being the first phylogenetic analyses to include the holopelagic Drieschia, we recovered this species nested among shallow water terminals, suggesting a shallow water ancestry. Based on these results, our phylogenetic reconstructions showed that swimming evolved independently three times in Polynoidae, involving convergent adaptations in morphology and motility patterns across the deep sea (Branchipolynoe), midwater (Drieschia) and anchialine caves (Pelagomacellicephala and Gesiella). Phylogenetic generalized least-squares (PGLS) analyses showed that holopelagic and anchialine cave species exhibit hypertrophy of the dorsal cirri, yet, these morphological modifications are achieved along different evolutionary pathways, i.e., elongation of the cirrophore versus style. Together, these findings suggest that a water column lifestyle elicits similar morphological adaptations, favouring bodies designed for drifting and sensing.

Broad North Atlantic distribution of a meiobenthic annelid - against all odds

DNA barcoding and population genetic studies have revealed an unforeseen hidden diversity of cryptic species among microscopic marine benthos, otherwise exhibiting highly similar and simple morphologies. This has led to a paradigm shift, rejecting cosmopolitism of marine meiofauna until genetically proven and challenging the "Everything is Everywhere, but the environment selects" hypothesis that claims ubiquitous distribution of microscopic organisms. With phylogenetic and species delimitation analyses of worldwide genetic samples of the meiofaunal family Dinophilidae (Annelida) we here resolve three genera within the family and showcase an exceptionally broad, boreal, North Atlantic distribution of a single microscopic marine species with no obvious means of dispersal besides vicariance. With its endobenthic lifestyle, small size, limited migratory powers and lack of pelagic larvae, the broad distribution of Dinophilus vorticoides seems to constitute a "meiofaunal paradox". This species feasts in the biofilm among sand grains, but also on macroalgae and ice within which it can likely survive long-distance rafting dispersal due to its varying lifecycle stages; eggs encapsulated in cocoons and dormant encystment stages. Though often neglected and possibly underestimated among marine microscopic species, dormancy may be a highly significant factor for explaining wide distribution patterns and a key to solving this meiofaunal paradox.

Phylogeny and biogeography of the scaleless scale worm Pisione (Sigalionidae, Annelida)

Pisione is a scaleless group of small scale worms inhabiting sandy bottoms in shallow marine waters. This group was once considered rare, but now 45 described species can be characterized, among others, by their paired, segmental copulatory organs (one to multiple external pairs), which display a complexity of various accessory structures. The evolutionary significance of these unique organs was suggested in the late 1960s, but has been heavily debated since the late 1990s and remains controversial. In the present paper, we study the internal relationships within Pisione, employing combined phylogenetic analyses of both molecular and morphological data from 16 terminals of Pisione, as well as two terminals of Pisionidens, and eight additional scale worms as outgroups. Our taxon sampling covers all geographical areas where the genus has been reported, as well as most of their morphological and copulatory variability, including representatives of the "africana," "remota," "crassa," and "papuensis" groups, established previously by Yamanishi. We hereby provide a first insight into the relationships of the genus, testing previously proposed hypotheses on the evolutionary significance of male copulatory structures within Pisione, while attempting to understand patterns of distribution. The phylogenetic analyses using maximum likelihood and Bayesian methods consistently recovered two large clades spanning the East Atlantic (including the Mediterranean) and the Indo-Pacific-West Atlantic, respectively. Character optimization on our trees revealed a high degree of homoplasy in both non-reproductive and sexual characters of Pisione, with buccal acicula found to be the sole apomorphy among the morphological features assessed herein, with none defining the biogeographical subclades within. Overall, our comparative analyses highlight the high degree of morphological variation in this widely distributed genus, rejecting previous assertions of an increasing number and complexity of copulatory structures across the genus.

In situ ingestion of microfibres by meiofauna from sandy beaches

Microfibres are widespread contaminants in marine environments across the globe. Detecting in situ ingestion of microfibres by small marine organisms is necessary to understand their potential accumulation in marine food webs and their role in marine pollution. We have examined the gut contents of meiofauna from six sandy beaches in the Atlantic Ocean and the Mediterranean. Out of twenty taxonomic groups, three species of the common sandy beach annelid Saccocirrus displayed in situ ingestion of microfibres in all sites. Laboratory observations showed that species of Saccocirrus are able to egest microfibres with no obvious physical injury. We suggest that their non-selective microphagous suspension-feeding behaviour makes Saccocirrus more prone to ingest microfibres. Although microfibres are rapidly egested with no apparent harm, there is still the potential for trophic transfer into marine food webs through predation of Saccocirrus.

New species of Pisionidens (Sigalionidae, Annelida) from Akumal, México

Pisionidens Aiyar & Alikuhni, 1943 is a genus of small scale-less annelids formerly belonging to the family 'Pisionidae', now synonymized with the scale worm family Sigalionidae. A new species from Akumal, México, Pisionidens ixazaluohae n. sp., is herein described, including a genetic barcode, and diagnosed by parapodia from segment 8, males having a continuous line of midventral pores, and the presence of a single copulatory segment without parapodia. The new species differs in morphology from the three previously described species, including P. indica (Aiyar & Alikuhni, 1940), representing the only other species previously reported from the Caribbean Sea and Gulf of Mexico. A comparative table with a summary of the main taxonomic characters of all described species of the genus, including information on distribution, is provided.

The use of microsensors to study the role of the loading rate and surface velocity on the growth and the composition of nitrifying biofilms

The good composition and activity of biofilms are very important for successful operation and control of fixed-film biological reactors employed in liquid effluents treatment. During the last decade, microsensors have been applied to study microbial ecology. These sensors could provide information regarding the microbial activity concerning nitrification and denitrification that occur inside biofilms. Other techniques of molecular biology, such as fluorescence in situ hybridization (FISH), have also contributed to this matter because their application aids in the identification of the bacterial populations that compose the biofilms. The focus of this paper was to study the loading rate and surface velocity to promote the development of nitrifying biofilms in three distinct flow cells that were employed in the post treatment of a synthetic wastewater simulating the effluent from a UASB (Upflow Anaerobic Sludge Blanket) reactor. Using the FISH technique, it was found that the population of ammonia-oxidizing-bacteria was greater than that of nitrite-oxidizing-bacteria; this was also supported by the lower production of nitrate determined by physicochemical and microsensor analyses. It was verified that the loading rate and surface velocity that promoted the greatest nitrogen removal were 0.25 g N-amon m(-2)biofilm day(-1) and 1 m h(-1), respectively.

Elderly Mexican women's perceptions of exercise and conflicting role responsibilities

The purpose of this pilot study was to explore elderly Mexican women's readiness to exercise, and their multiple roles. Fifty older women were sampled from two separate neighborhoods of low socio-economic status. Readiness to exercise was examined using the Stages of Change - Exercise instrument with six categories: precontemplation nonbelievers, precontemplation believers, contemplation, preparation, action, and maintenance. Time devoted to the following functional roles was explored: wife, household, grandmother, personal care, and recreational. Women fell mainly under the first three stages of change both, precontemplation nonbelievers and believers, and the contemplation stage. The stages of change scale and role commitments were not significantly related. Nevertheless, precontemplators devoted less time in all the roles than the women in the other categories of stage of change.