Pseudostomella Dolichopoda Todaro, 2012 and P. cataphracta Ruppert, 1970 (Gastrotricha: Thaumastodermatidae): new records from Brazil and USA and an updated key to the genus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Pseudostomella dolichopoda was originally described from the north coast of Sao Paulo, Brazil, and P. cataphracta from North Carolina, USA. Herein we report new distributional records of both species: P. dolichopoda is recorded from Espirito Santo, Brazil and P. cataphracta from Florida, USA. An updated identification key for the genus Pseudostomella is also provided. © 2016 Check List and Authors.Pseudostomella dolichopoda was originally described from the north coast of Sao Paulo, Brazil, and P. cataphracta from North Carolina, USA. Herein we report new distributional records of both species: P. dolichopoda is recorded from Espirito Santo, Brazil12617CNQP - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)478825/2013-72014/23856-0This work was supported by grants from Conselho Nacional de Desenvolvimento Científico e Tecnológico – CNPq (478825/2013-7), Programa de Inovação e Qualidade no Ensino de Graduação – UFMG (PIQEG 2014-31) and Fundação de Amparo á Pesquisa do Estado de Sã

Pseudostomella dolichopoda Todaro, 2012 and P. cataphracta Ruppert, 1970 (Gastrotricha: Thaumastodermatidae): new records from Brazil and USA and an updated key to the genus

Pseudostomella dolichopoda was originally described from the north coast of São Paulo, Brazil, and P. cataphracta from North Carolina, USA. Herein we report new distributional records of both species: P. dolichopoda is recorded from Espírito Santo, Brazil and P. cataphracta from Florida, USA. An updated identification key for the genus Pseudostomella is also provided

Spatio-temporal changes in the abundance of the populations of the gastrotrich community in a shallow lake of tropical Africa

AbstractStudies on the biodiversity and population dynamics of freshwater planktonic Gastrotricha have been carried out in conjunction with a physical–chemical analysis of the water in the Yaounde Municipal Lake (Cameroon, Central Africa) over a 14 months period (November 1996–December 1997). The results obtained allow to consider the Yaounde Municipal Lake as an eutrophic lake. It harbours eight species of Gastrotricha belonging to four genera (Chaetonotus, Dasydytes, Neogossea and Polymerurus) of the order Chaetonotida. This community was characterized by high abundances of populations, and was dominated by the genus Neogossea and Chaetonotus reaching up to 2000ind.L−1. Polymerurus was mostly abundant at the almost anoxic bottom layers. The highest abundances were found mostly during the rainy season, when there is an important sedimentation process of organic matter, and were influenced by several different environmental factors such as dissolved oxygen, temperature and pH of the water.Finally this community which may play an important role in the water bodies, is a potential water quality indicator

Gastrotricha: A Marine Sister for a Freshwater Puzzle

Background: Within an evolutionary framework of Gastrotricha Marinellina flagellata and Redudasys fornerise bear special interest, as they are the only Macrodasyida that inhabit freshwater ecosystems. Notwithstanding, these rare animals are poorly known; found only once (Austria and Brazil), they are currently systematised as incertae sedis. Here we report on the rediscovery of Redudasys fornerise, provide an account on morphological novelties and present a hypothesis on its phylogenetic relationship based on molecular data. Methodology/Principal Findings: Specimens were surveyed using DIC microscopy and SEM, and used to obtain the 18 S rRNA gene sequence; molecular data was analyzed cladistically in conjunction with data from 42 additional species belonging to the near complete Macrodasyida taxonomic spectrum. Morphological analysis, while providing new information on taxonomically relevant traits (adhesive tubes, protonephridia and sensorial bristles), failed to detect elements of the male system, thus stressing the parthenogenetic nature of the Brazilian species. Phylogenetic analysis, carried out with ML, MP and Bayesian approaches, yielded topologies with strong nodal support and highly congruent with each other. Among the supported groups is the previously undocumented clade showing the alliance between Redudasys fornerise and Dactylopodola agadasys; other strongly sustained clades include the densely sampled families Thaumastodermatidae and Turbanellidae and most genera. Conclusions/Significance: A reconsideration of the morphological traits of Dactylopodola agadasys in light of the new information on Redudasys fornerise makes the alliance between these two taxa very likely. As a result, we create Anandrodasys gen. nov. to contain members of the previously described D. agadasys and erect Redudasyidae fam. nov. to reflect this novel relationship between Anandrodasys and Redudasys. From an ecological perspective, the derived position of Redudasys, which is deeply nested within the Macrodasyida clade, unequivocally demonstrates that invasion of freshwater by gastrotrichs has taken place at least twice, in contrast with the single event hypothesis recently put forward

Biodiversity estimates and ecological interpretations of meiofaunal communities are biased by the taxonomic approach

Accurate assessments of biodiversity are crucial to advising ecosystem-monitoring programs and understanding ecosystem function. Nevertheless, a standard operating procedure to assess biodiversity accurately and consistently has not been established. This is especially true for meiofauna, a diverse community (>20 phyla) of small benthic invertebrates that have fundamental ecological roles. Recent studies show that metabarcoding is a cost-effective and timeeffective method to estimate meiofauna biodiversity, in contrast to morphological-based taxonomy. Here, we compare biodiversity assessments of a diverse meiofaunal community derived by applying multiple taxonomic methods based on comparative morphology, molecular phylogenetic analysis, DNA barcoding of individual specimens, and metabarcoding of environmental DNA. We show that biodiversity estimates are strongly biased across taxonomic methods and phyla. Such biases affect understanding of community structures and ecological interpretations. This study supports the urgency of improving aspects of environmental high-throughput sequencing and the value of taxonomists in correctly understanding biodiversity estimates

Phenotypic Plasticity Opposes Species Invasions by Altering Fitness Surface

Understanding species invasion is a central problem in ecology because invasions of exotic species severely impact ecosystems, and because invasions underlie fundamental ecological processes. However, the influence on invasions of phenotypic plasticity, a key component of many species interactions, is unknown. We present a model in which phenotypic plasticity of a resident species increases its ability to oppose invaders, and plasticity of an invader increases its ability to displace residents. Whereas these effects are expected due to increased fitness associated with phenotypic plasticity, the model additionally reveals a new and unforeseen mechanism by which plasticity affects invasions: phenotypic plasticity increases the steepness of the fitness surface, thereby making invasion more difficult, even by phenotypically plastic invaders. Our results should apply to phenotypically plastic responses to any fluctuating environmental factors including predation risk, and to other factors that affect the fitness surface such as the generalism of predators. We extend the results to competition, and argue that phenotypic plasticity's effect on the fitness surface will destabilize coexistence at local scales, but stabilize coexistence at regional scales. Our study emphasizes the need to incorporate variable interaction strengths due to phenotypic plasticity into invasion biology and ecological theory on competition and coexistence in fragmented landscapes

Spatiotemporal Size-Class Distribution of Turbanella mustela (Gastrotricha: Macrodasyida) on a Northern California Beach and Its Effect on Tidal Suspension

The size-class distribution of the marine interstitial gastrotrich Turbanella mustela Wieser was analyzed at a high-energy beach in northern California. Five 100-um size classes, each corresponding to a particular sexual phase of the species, fluctuated in percentage abundance at both temporal and spatial scales. On average, the most abundant size classes over the 3-day period were the 100-199-um group (prereproductive juveniles) and the 200-299-um group (male phase). Significant differences were evident spatially, where aggregations at the vertical and horizontal level contributed to patchy size-class distributions. Members of the largest size class (postreproductive or male phase) were in low abundance, and juveniles and reproductive individuals made up the bulk of the population. The smallest size class (100-199 um) was most aggregated in the top 5 cm of sand and differed significantly in percentage abundance from all other size classes at that depth. This size class is also the only size class to decrease significantly in percentage abundance on a vertical scale and increase in percentage abundance on a horizontal scale. Three hypotheses accounting for the observed size-class variations are entertained: sexual phase stratification, interspecific interactions, and intraspecific trophic relations. All three hypotheses are important for understanding the importance of these size-class aggregations and may lead to a better understanding of the factors that influence local spatial patterns in gastrotrichs. Size-class stratification may also function in the planktonic dispersal of individuals in both tidal and longshore directions, ultimately affecting the geographic distribution of the species

Cephalopharynx cannoni Hochberg 2004, sp. nov.

<i>Cephalopharynx cannoni</i> sp. nov. <p>(figures 2–7)</p> <p> <i>Material examined</i></p> <p>HOLOTYPE: Australia, Queensland, North Stradbroke Island, Amity Point, intertidal in medium sand (June 2002), whole-mount (polyvinyl lactophenol): G219290.</p> <p>PARATYPES: same location as holotype, two adult whole-mounts (polyvinyl lactophenol): G219291–G219292; three immature wholemounts (polyvinyl lactophenol): G219293–G219295; two sectioned specimens stained with Mallory’s trichrome: G219296–G219297.</p> <p> <i>Other material.</i> Fourteen specimens collected intertidally, studied alive and as whole-mounts (June 2002). One specimen collected subtidally in July 2002.</p> <p> <i>Etymology</i></p> <p> The genus and subfamily are named after the anterior position of the pharynx (greek <i>cephalo</i>: head; greek <i>pharynx</i>: throat). Species epithet is dedicated to Dr Lester R. G. Cannon, former Senior Curator of Invertebrate Zoology at the Queensland Museum.</p> <p> <i>Description</i></p> <p> Animals to 384 <i>µ</i> m long and 192 <i>µ</i> m wide with an oval body (figure 2). A tail is never present. Body opaque with a glandular intestine. The entire epidermis is ciliated and may be partly syncytial. Epidermis height to 8 <i>µ</i> m in section with cilia to 6 <i>µ</i> m long. The distal edge of the epithelium is strongly eosinophilic. Dermal and adenal rhabdites absent. Anterior kidney-shaped eyes present and consisting of numerous small (<i>ca</i> 1–2 <i>µ</i> m) black pigment granules. Ventral and slightly posterior to the eyes is a vertically orientated pharynx rosulatus to 58 <i>µ</i> m long and 46 <i>µ</i> m wide (figure 3). The pharynx has a slight posterior incline. In cross-section, approximately 20 columnar cells are present, each <i>ca</i> 9 <i>µ</i> m high with translucent cytoplasm and a basal nucleus. Posteriorly, the pharynx leads into a short oesophagus and a sac-shaped gut that extends to about three-quarters of the body length. In section, gut cells are either translucent or highly eosinophilic and to 12 <i>µ</i> m high. Some cells are shaped as inverted goblets. Diatoms were regularly present in the gut lumen. Subepidermal musculature consists of circular and longitudinal fibres. In one crosssection, approximately 10 longitudinal muscles could be counted in a 50 <i>µ</i> m span. Caudal adhesive glands absent. Protonephridia difficult to identify in most specimens but appear to branch posterior to pharynx and open separately behind mouth.</p> <p> <i>Male reproductive system.</i> A single elongate testis is present immediately behind the pharynx and ventral to the vitellaria (figure 3). The testis is orientated transversely but curved along its length. The exact position of the testis is somewhat variable in living specimens. The left side is a compact germinal zone while free sperm are present along the curve and anterior portion of the testis. The entire testis is lined with circular musculature. In cross-section, the testis is 24 <i>µ</i> m diameter. Anteriorly, the testis leads into a slightly more dorsal vesicula granulorum, also curved. The vesicula granulorum is highly elongate and bent at <i>ca</i> 50% length (figure 4A, B, D). Externally, it is lined with thick (3 <i>µ</i> m) spiral muscles, and internally, masses of small (1 <i>µ</i> m), circular, eosinophilic secretions are present along the entire length (figure 4C, D). The spiral musculature of the vesicula granulorum is continuous with the male genital canal that houses a sclerotic stylet. The spiral musculature of the canal, however, is more circularly orientated, thinner (1–2 <i>µ</i> m), and also lines a series of longitudinal muscles. Circular muscles do not extend down to the atrium, but stop at the distal end of the stylet. The eosinophilic secretions of the vesicula granulorum are present in the proximal opening of the canal and stylet, and masses of secretions (presumably as compact glands) are present outside the male canal on either side (figures 4C, 5A). The stylet is an elongate tubular organ, to 108 <i>µ</i> m long, with two slight bends along its length (figure 5B, 6). The proximal opening is rimmed and up to 15 <i>µ</i> m wide. Approximately 3 <i>µ</i> m from the opening is an external ring followed by a pair of shark fin-shaped structures (9 <i>µ</i> m long) on either side. The stylet narrows to 11 <i>µ</i> m at <i>ca</i> 50% length. Close to the distal end is a bendable lip-like structure to 54 <i>µ</i> m long. When in the male canal, the lip-like structure is bent back along the length of the stylet. During fixation, the lip unfolds from the stylet.</p> <p> <i>Female reproductive system.</i> The female organs include paired vitellaria, a single ovary, bursa, and uterus (figure 3). Paired vitellaria extend from 30% body length to the posterior one-third of the body. Vitellaria are compact eosinophilic strands, approximately 15 <i>µ</i> m high by 10 <i>µ</i> m wide in section, and ventro-lateral to the gut. Caudally, the vitellaria connect to the common female genital canal close to the site of the ovary. The canal is highly muscular with thick walls surrounded by longitudinal muscles (figures 3, 7). Distally, the canal leads into a uterus. The walls of the uterus were lined with longitudinal muscles extending from the female canal. A light, alcian blue-staining flocculent material was always present in the lumen of the uterus. Proximal to the uterus and ovary is an elongate bursa, sheathed in longitudinal muscle, and partially collapsed in all specimens examined.</p> <p> <i>Cladistics.</i> Eleven characters were assembled for cladistic analysis (tables 1, 2). A heuristic search found seven most parsimonious trees (Length <b>=</b> 19, Consistency Index <b>=</b> 0.684, Retention Index <b>=</b> 0.647). The strict consensus tree placed Phaenocorinae as the most basal subfamily within the Typhloplanidae with Cephalopharynginae as the sister group to the remaining seven families (figure 8). Typhloplaninae and Mesostominae were sister taxa with 55% bootstrap support. There was 67% bootstrap support for Cephalopharynginae plus the remaining seven families. Selective exclusion of protonephridial characters (3 and 4) resulted in a single most parsimonious tree (figure 9A; L <b>=</b> 14, CI <b>=</b> 0.625, RI <b>=</b> 0.571). Removal of characters pertaining to the testes (8–10) resulted in 20 most parsimonious trees (figure 9B; L <b>=</b> 14, CI <b>=</b> 0.714, RI <b>=</b> 0.636). Exclusion of pharyngeal characters (1 and 2) resulted in 43 most parsimonious trees with minimal resolution of ingroup relationships in a strict consensus tree (L <b>=</b> 16, CI <b>=</b> 0.625, RI <b>=</b> 0.571).</p> <p>Increasing the number of heuristic replications to 10 000 failed to find additional trees. A branch and bound search was also employed in PAUP but resulted in the same number of trees and same tree topology as the original heuristic search. An exhaustive search also found seven most parsimonious trees with shortest length of 19.</p>Published as part of <i>Hochberg, Rick, 2004, A new genus and subfamily of Typhloplanidae (Platyhelminthes, Rhabdocoela) from Australia with a cladistic analysis of subfamily relationships, pp. 925-937 in Journal of Natural History 38 (8)</i> on pages 928-933, DOI: 10.1080/0022293021000058970, <a href="http://zenodo.org/record/4653743">http://zenodo.org/record/4653743</a&gt

Cephalopharynx Hochberg 2004, gen. nov.

Genus <i>Cephalopharynx</i> gen. nov. <p> <i>Diagnosis</i></p> <p>With characters of the subfamily. Testis without vas deferens, connects directly to vesicula granulorum. Stylet present. Single ovary, bursa and uterus. Paired strand-like vitellaria.</p>Published as part of <i>Hochberg, Rick, 2004, A new genus and subfamily of Typhloplanidae (Platyhelminthes, Rhabdocoela) from Australia with a cladistic analysis of subfamily relationships, pp. 925-937 in Journal of Natural History 38 (8)</i> on page 928, DOI: 10.1080/0022293021000058970, <a href="http://zenodo.org/record/4653743">http://zenodo.org/record/4653743</a&gt