Along‐ and across‐shore components of the spatial distribution of the clam Tivela mactroides (Born, 1778) (Bivalvia,Veneridae)

Beach clam fisheries often provide an alternate income for traditional fishermen, but this activity is highly vulnerable to urbanization of coastal areas. Tivela mactroides is a beach clam commonly harvested in the Caribbean (Venezuela) and on the south‐eastern Brazilian coast. Only localized records on its spatial structure in size and abundance are available to support management of this clam. The present study showed that the spatial distribution in abundance and size of T. mactroides in Caraguatatuba Bay, state of São Paulo, Brazil, has both along‐ and across‐shore (intertidal and subtidal) components. The nature of this distribution should be taken into account in the design of further population or monitoring studies concerning this species. Clam density varied along‐shore, with a tendency towards higher numbers of individuals in the stations near the northern side of river mouths of this bay. Lower densities were related to the occurrence of sea‐stars and sand‐dollars. The intertidal and subtidal across‐shore distribution of clam abundance and size varied between and within areas (southern and northern). The individuals from the southern area were concentrated at intermediate tidal levels (0.2–0.6 m in relation to mean low water), whereas in the northern area the clams were more homogeneously distributed. The uppermost limit of their distribution was 0.8 m (southern) and 0.4 m (northern), and an upwards tendency towards increased size was more evident in the northern area. In the subtidal, abundance and individual size tended to increase from the deepest (4.5 m) to the shallowest (0.5 m) levels only in the southern area. Individual clams in the northern area tended to be smaller and more abundant than in the southern area. The species had an ontogenic distribution: small‐sized individuals were recorded only in the subtidal. Possible causes for these patterns and for the differences between areas (human exploitation, organic pollution, beach morphodynamics, differential recruitment, and adult–larvae interactions) are discussed, and specific studies are suggested to evaluate formally the proposed hypotheses.     

Similiclava nivea (Cnidaria: Hydrozoa: Similiclavidae): a new family,genus and species of athecate hydroid from the Pacific coast of North America

The hydroid Similiclava nivea, gen. nov., sp. nov., is described from colonies collected in nearshore waters of southern British Columbia, Canada. It has been observed by divers, and recorded as Clava sp., several hundred times at locations between southeast Alaska and southern Oregon, USA. While resembling the hydractiniid Clava multicornis, tentacles of S. nivea are arranged in two close whorls in extended hydranths rather than being scattered over the distal end of the hydranth. Moreover, the hypostome is dome-shaped to flattened instead of being proboscidiform. Similiclava nivea also resembles species of the hydractiniid genera Stylactaria, Hydractinia and Podocoryna, but differs in being monomorphic, in lacking spines on the hydrorhiza and in having numerous (as many as 50 or more) sporosacs borne in a broad whorl below the tentacles on normal hydranths. Molecular analysis using the mitochondrial 16S gene sequences reveals that S. nivea is closer to Clathrozoellidae than to Hydractiniidae, although it is clearly distinct from both. A new family, Similiclavidae, is established to accommodate the species. Hydroids of S. nivea were observed at relatively shallow depths (10–30 m) on rocks and epibiota attached to rocky substrates. Colonies are conspicuous because of the relatively large surface area they occupy (up to 20 cm across, and in aggregations often exceeding 100 or more hydranths) together with the height (about 15 mm high when extended) and striking white colour of living hydranths. The cnidome consists of desmonemes, microbasic euryteles and microbasic mastigophores. A substrate generalist observed on rocks, algae, sponges, barnacles, bryozoans and other hydroids in cold-temperate waters, S. nivea is most prevalent in shallow subtidal areas swept by tidal currents.

http://zoobank.org/urn:lsid:zoobank.org:pub:2691E02E-7E14-4820-8D91-41D9E7E8BF62     

Three new species of Pogonophora,including two vestimentiferans,from hydrothermal sites in the Lau Back-arc Basin (Southwest Pacific Ocean)

Hydrothermal fields on the Valu Fa Ridge at about 22°32′S, 176°43′W, were explored by the submersible Nautile during the French BIOLAU expedition in 1989. Pogonophorans were found during six of the 12 dives, at depths of about 1900 m. They were exposed to the influence of hydrothermal fluids but probably did not experience elevated temperatures. One new species of sediment-living perviate pogonophore was collected. Two new obturate pogonophores (vestimentiferans), one belonging to a new family, lived attached to hard substrata. There is a complete faunistic separation of the Lau Basin vestimentiferans from the eastern Pacific vent faunas. Families as well as genera are different, and the Lau species appear to have more in common with cold seep faunas.     

Four new species of Mesomyzostoma (Myzostomida: Annelida)

Mesomyzostoma Remscheid, 1918 currently includes three described species that live in the coelom and/or gonads of comatulid crinoids: Mesomyzostoma reichenspergeri Remscheid, 1918, Mesomyzostoma katoi Okada, 1933 and Mesomyzostoma lanterbecqae Summers and Rouse, 2014 in Summers, Al-Hakim et al. 2014. Here we describe four new species of Mesomyzostoma and assess their phylogenetic relationships using 18S rRNA, cytochrome oxidase subunit I and 16S rRNA sequence data. We also designate a neotype for M. katoi as the original types appear to be lost. We record M. reichenspergeri from the Australian Great Barrier Reef and from northern Papua New Guinea, but samples from the type locality (Aru Islands, Indonesia) and previously recorded host are needed for confirmation. The new species of Mesomyzostoma are one Japanese species: Mesomyzostoma okadai sp. nov., and three Australian species: Mesomyzostoma lobus sp. nov., Mesomyzostoma leukos sp. nov. and Mesomyzostoma botulus sp. nov. The first infects the coelom of crinoid arms and pinnules, and the other three are found in crinoid oral discs. We also record M. leukos sp. nov. and M. botulus sp. nov. from Papua New Guinea. Phylogenetic analyses suggest that M. okadai sp. nov. is the sister group to all other Mesomyzostoma.     

Biological characterization of the obligate symbiosis between Acropyga sauteri Forel (Hymenoptera: Formicidae) and Eumyrmococcus smithii Silvestri (Hemiptera: Pseudococcidae: Rhizoecinae) on Okinawa Island,southern Japan

The ant Acropyga sauteri Forel has an obligate, mutualistic symbiosis with a mealybug, Eumyrmococcus smithii Silvestri, on Okinawa Island, southern Japan. The mealybugs live inside ant nests nearly all their lives, and the ants depend on them for food. Alate foundress queens carry mealybugs during their nuptial flights, using them to establish new colonies at new sites. However, important aspects of the symbiosis have not yet been elucidated. The present study characterizes the basic biology of the symbiosis and describes for the first time the morphologies of all growth stages of E. smithii. Our study suggests that E. smithii has only one nymphal stage, followed by a female pupal stage or male prepupal stage. Intensive sampling of ant nests across seasons showed that A. sauteri prefers nest sites 5–20 cm underground. Acropyga sauteri produced reproductive stages mainly in mid‐March or early April, and numbers of both ant workers and mealybugs increased from spring to summer. Experimental determination of colony identity with a method using nestmate recognition by ants suggested that each ant colony rarely has a perimeter greater than 30 cm, that the ants are monogynous, and that different ant colonies are densely aggregated along the root system of a plant, adjacent to each other but not interflowing. Both symbiotic partners were vulnerable to attacks by several common subaerial ant species following physical disturbance to their nests.     

Hybridization of beaked redfish (Sebastes mentella) with small redfish (Sebastes viviparus) and diversification of redfish (Actinopterygii: Scorpaeniformes) in the Irminger Sea

We searched for Sebastes mentella and Sebastes viviparus hybrids in samples of redfish with external traits typical of S. mentella. The samples were collected in the Irminger Sea in 2007 (n = 131) and 2010 (n = 72). Hybrids were identified using MDH-2* locus coding malate dehydrogenase. Both samples contained hybrids (two and one individuals, respectively). The results of our investigations and previously published data show that interspecific hybridization may have a strong impact on the genetic structure of S. mentella in the Irminger Sea, presumably being one of the main reasons for the differentiation of allele frequencies of some genes between samples collected at different depths. This should be taken into consideration in studies of Irminger Sea redfish.     

Crustaceans associated with the deep-water gorgonian corals Paragorgia arborea (L., 1758) and Primnoa resedaeformis (Gunn., 1763)

To explore the crustacean fauna associated with deep-water gorgonian corals, suction samples were taken from colonies of Paragorgia arborea and Primnoa resedaeformis using a Remotely Operated Vehicle. Seven colonies of P. arborea and eight of P. resedaeformis were sampled from 330–500?m depth in the Northeast Channel off Nova Scotia. A total of 17 species were identified as being associated with the corals. The P. arborea fauna was richer than the P. resedaeformis fauna in both abundance and number of species, with 1303 versus 102 individuals and 16 versus seven species, respectively. However, 13 of the species associated with P. arborea were from hydroids attached to the coral. Amphipods dominated the fauna both in abundance and numbers of species and the most common species were Metopa bruzelii, Stenopleustes malmgreni, Proboloides calcarata and Aeginella spinosa. The isopod Munna boecki and the cirripede Ornatoscalpellum stroemii were also quite common. The most strongly associated crustaceans were two parasitic poecilostomatid copepods; these are common also on tropical gorgonians and are most likely obligate associates. The frequently occurring shrimp Pandalus propinquus probably avoids predation by seeking protection among the coral branches. Shrimp counts from video records showed that visual inspection without physically disturbing colonies will generally not reveal the crustaceans hidden in coral colonies. The galatheid Eumunida picta was observed on P. resedaeformis colonies. The fauna of the deep-water gorgonians corresponded to the fauna of tropical shallow-water gorgonians in the numerical dominance of amphipods and parasitic copepods; however, species richness is higher and decapods, which constitute a rich fauna on tropical gorgonians, were only represented by two species.     

Taxonomic revision and systematic notes on some Halecium species (Cnidaria,Hydrozoa)

Although the genus Halecium is easy to recognize, identifications at the species level are often difficult, this even for quite common and supposedly well‐known species of the north‐eastern Atlantic. This paper revises and re‐describes some Halecium species which resemble each other closely and which are not easy to distinguish. Additional information on a few rare species is also provided. The study is based on material collected from the North Atlantic, Mediterranean, South Africa, and New Zealand. Halecium scutum Clark, is recognized as a valid species and distinct from both H. beanii and H. halecinum; colony form and microscopic characters allow a distinction. The pinnate colony form of H. halecinum is a characteristic trait, but not all colonies show this growth form. Halecium beanii can occur in monosiphonic and polysiphonic colonies. Monosiphonic colonies of H. beanii have probably been misidentified by some authors as H. lankesterii. The differences of H. lankesteri to H. beanii and H. petrosum are discussed. The South African population of the reportedly cosmopolitan H. beanii has distinct gonothecae and could belong to a separate species. The Mediterranean Halecium mediterraneum is hardly distinguishable from the New Zealandic H. delicatulum, but it is kept separate mainly for biogeographic reasons. The rare Mediterranean Halecium banyulense is re‐described based on a second find from Naples. The male gonothecae of Halecium corrugatissimum are described for the first time.     

Ecology and field biology of two dominant Camponotus ants (Hymenoptera: Formicidae) in the Brazilian savannah

Camponotus renggeri and C. rufipes are very abundant in Brazilian cerrado savannah, where they feed extensively on liquid rewards and commonly associate with plants bearing extrafloral nectaries and honeydew-producing insects. Here, we provide a qualitative and quantitative field account on the natural history and ecology of these two ant species. The study was carried out in a cerrado reserve in south-eastern Brazil across a rainy/hot season (summer) and a dry/cold season (winter). The ants were found in two vegetation physiognomies: all nests of C. rufipes were located in the cerrado sensu stricto (scrub of shrubs and trees, 3–8 m tall), whereas C. renggeri occurred mostly in the cerradão (forest with more or less merging canopy, 10–12 m tall). Both species nested in fallen or erect dead trunks, as well as underground. In addition, C. rufipes built nests using dead plant material arranged or not around shrub bases. Colonies of C. rufipes were generally more populous than those of C. renggeri, and both species had colonies with more than one dealated queen. Both species were active mainly at night and foraged for resources near their nests, mainly extrafloral nectar and hemipteran honeydew (aphids and mealybugs). The average size of the home ranges of C. renggeri in cerrado sensu stricto and cerradão varied from ≈ 2.8 to 4.0 m² and apparently were not affected by season. In C. rufipes, however, foraging grounds in cerrado sensu stricto showed a twofold increase from dry/cold (≈ 4.5 m²) to rainy/hot season (≈ 9.8 m²). Our study highlights the importance of natural history data to understand the foraging ecology and role of these ants in cerrado savannah.     

Observations on the spectral reflectances of certain high Andean Penaincisalia and Thecloxurina,with the description of a new species (Lepidoptera: Lycaenidae: Eumaeini)

The eumaeine hairstreak species Thecloxurina tegulina Bálint and Boyer, sp. n. from SW Peru, department Apurímac (type locality: Karkatera, NW of Ampay, 3,200 m, 13°34′286″S; 72°58′501″W) is described on the basis of qualitative and quantitative wing pattern, male genital and spectral characters. The spectral reflectance of the closely related genera Penaincisalia and Thecloxurina are investigated and compared. It is demonstrated that the spectral characteristics of the two genera are qualitatively differing, and the taxa investigated representing the two genera (Penaincisalia:Thecloxurina = 3:5) also have characteristic species dependent reflectance peaks measured at normal incidence.     

Taxonomy of the genus Tantunema Siddiqi, 1982 (Dorylaimida: Tylencholaimidae) with description of one new and two known species

One new and two known species of the genus Tantunema Siddiqi, 1982 are described and illustrated. Tantunema indicum sp. nov. is characterized by having a small body (length 0.32–0.45 mm); lip region cap-like, set off by slight constriction; odontostyle 6–7 µm and odontophore 8–10 µm long; pharyngeal expansion gradual, expanded part occupying about 35–41% of total neck length, lumen of posterior expanded part widened and thickened; female genital system mono-opisthodelphic, anterior genital branch absent; tail short, hemispheroid, 0.8–1.1 anal body diameter long. Tantunema pakistanense (Timm, 1964) comb. nov. (=Tylencholaimus pakistanensis Timm, 1964) and Tantunema intermedium (Peña-Santiago and Coomans, 1996) Andrássy, 2009 are redescribed. A diagnostic compendium and key to species of the genus is also provided.     

The hermit crab Sympagurus dimorphus (Anomura: Parapaguridae) at the edge of its range in the south-western Atlantic Ocean: population and morphometry features

Sympagurus dimorphus is one of the 12 hermit crab species recorded for Argentinean waters. Despite the high abundance registered in some scallop fishing grounds, its biology remains little known. In the present study, we analysed some population features of S. dimorphus living in symbiosis with Epizoanthus paguricola from a series of samples taken in the Argentine Sea, south-western Atlantic Ocean. Our results showed that S. dimorphus was commonly found from 40ºS to lower latitudes, in a patchy distribution along the shelf-break front. The overall sex ratio was 1:1. The smallest ovigerous female measured 6 mm in cephalothoracic shield length and this size was used as parameter to define the size of juveniles. The sex ratio size class pattern corresponded to Type IV or anomalous curve. S. dimorphus is a dimorphic species, as evidenced by the larger size of the males and the positive allometric growth of the right cheliped. The species also showed asymmetry, with the left uropod always larger than the right one. To the best to our knowledge, this is the first report on population features and relative growth for a member of the genus, based on long-term sampling. This species presents a patchy distribution along the shelf-break of Argentina. Its density tended to decrease over the five-year sampling period regarding the recruitment of hermits associated with colonies of zoanthids. In addition, the relatively homogeneous nature of this refuge does not seem to influence the growth of the hermit crab, which presents sexual dimorphism in relation to the sex/size conditions.     

Review of the Fridericia species (Oligochaeta: Enchytraeidae) possessing two spermathecal diverticula and description of a new species

A new Fridericia species (Fridericia lacii sp. nov.) is described. Including this new species the number of valid Fridericia species with two diverticula per spermatheca is 50. The present study provides an opportunity for the comparison and separation of Fridericia species on the basis of spermatheca and diverticulum characteristics. Nine tables summarize the two larger groups and five subgroups of species possessing bidiverticulate spermathecae. The new species is distinguished from all known valid congeners in this assemblage by the following combination of traits: (1) 4–7 mm long, 200–290 µm wide (in vivo) with 30–36 segments; (2) maximum four chaetae per bundle; (3) all pairs of pharyngeal glands with ventral lobes, the third is the largest with posterior projections; (4) only three pairs of preclitellar nephridia; (5) oesophageal appendages type a; (6) mucocytes type a, lenticytes small; (7) chylus cells in preclitellar segments; (8) clitellum girdle‐shaped, glands in transverse rows, between the bursal slits only granulocytes; bursal slit is longitudinal; (9) seminal vesicle small or absent; (10) sperm funnel one‐half as long as the body diameter, collar narrower than the funnel body; (11) subneural glands absent; (12) the ampulla of the spermatheca with two sessile (or with short stalks), spherical, thin‐walled diverticula, communication with the oesophagus separate, ectal duct about as long as body diameter, one floppy ectal gland at the orifice.     

Schistosoma curassoni Brumpt, 1931 in sheep and goats in Senegal

A survey of 5722 sheep and 1752 goats at the abatoir in Dakar, Senegal showed that the overall prevalence of schistosomiasis was 2·1%. Of the 112 animals where identification of the schistosome species was possible, all were infected with Schistosoma curassoni, and 2·7% had mixed infections with S. bovis. The adult worms of S. curassoni are described, and on the basis of egg morphology this species is shown to be distinct from S. bovis and S. mattheei. Eggs of S. curassoni measured 146 μm ± 16·8 × 63·3 μm ± 4·5 from sheep and 149·4 μm ± 13·2 × 62·8 μm ± 4·9 from mouse liver, and appear to be indistinguishable from the eggs of S. haematobium Guede Chantier, Senegal which measure 153·1 μm ± 11·1 × 62·4 μm ± 12·1 from mouse liver. However, S. curassoni differs from S. haematobium in that it develops more quickly than S. haematobium in hamsters, uterine eggs becoming visible at least 20 days earlier; the adult worms of S. curassoni are nearly double the size of S. haematobium in hamsters at 70 days post infection.

Also, S. curassoni develops well in sheep and cattle unlike S. haematobium, but will not develop to maturity in baboons like S. haematobium.     

Stephonyx californiensis sp. nov. (Amphipoda: Lysianassoidea: Uristidae), a new bathyal scavenger species from the Central Gulf of California,Mexico, and comments on the bathymetric and geographic distribution of the Stephonyx species group

A new species of scavenger amphipod of the genus Stephonyx is described and illustrated. The specimen was caught at 1150 m depth with a modified rectangular lobster trap positioned on the sea bottom in the central Gulf of California, Mexico. The new species is characterised by the absence of eyes; the lateral cephalic lobes medially developed and acute; antennae subequal in length; gnathopod 1 chelate, dactylus simple with three distal stout setae, inner margin sinuous with minute setae; gnathopod 2 subchelate, carpus with ventral margin crenulate, propodus subovate, palm deeply excavate, and dactylus slightly shorter than palm; maxilliped inner plate laceolate, with seven marginal nodular robust setae, distally; telson, each lobe with two dorsal robust setae, distal margin truncated, with one penicillate and two simple setae, in addition to two short spines. Stephonyx californiensis sp. nov. is morphologically similar to S. arabiensis, S talismani, S. laqueus and S. perexcavatus. The new species increases the number of Stephonyx species around the world to 14, with one species inhabiting from the continental shelf to abyssal depths (to 3000 m), 11 species occurring in bathyal depths (201–2000 m), and two other species restricted to abyssal depths (2001–4000 m).

www.zoobank.org/urn:lsid:zoobank.org:pub:346C3B15-E56A-4E17-9C5F-C9FDBB2AED92     

A new genus of Atlantic octocorals (Octocorallia: Gorgoniidae): systematics of gorgoniids with asymmetric sclerites

Gorgonian corals from the families Gorgoniidae and Plexauridae are among the most abundant and diverse shallow‐water cnidarians found along tropical and temperate Atlantic coasts and reefs. Some morphological traits in the Gorgoniidae comprise a taxonomic challenge due to their morphological plasticity as well as a lack of discrete character states among most genera. Some gorgoniids have asymmetrical sclerites in the surface coenenchyme, a character trait that consists of a continuum among several genera and can cause confusion with members of the family Plexauridae. The collection of a unique gorgoniid in Tobago (Trinidad and Tobago), which contains this trait but also maintains affinities to many different genera, stimulated a wider morphological comparison of gorgoniids using scanning electron microscopy (SEM). Using the morphology of asymmetrical sclerites, gorgoniids could be grouped in four monophyletic clades that were compatible with recent molecular phylogenies and provide a provisional subfamilial classification: (1) a derived clade including gorgoniids with scaphoid sclerites, comprising the reef fauna from the western Atlantic (e.g. Gorgonia, Pseudopterogorgia [ = Antillogorgia], Pterogorgia, and Phyllogorgia); (2) a related group with taxa containing capstan sclerites including genera with short capstans and/or disk‐spindles sclerites such as Pacifogorgia and Leptogorgia ( = Lophogorgia); (3) a clade of gorgoniids with asymmetrical spiny sclerites including the Atlantic genus Muriceopsis and the Indopacific Pinnigorgia together with the distant single species from the new genus and species Tobagogorgia hardyi (it is worth noting that Muriceopsis was previously classified in the Plexauridae, but there is overwhelming molecular support that groups it with the Gorgoniidae and morphological evidence that suggests affinity with Pinnigorgia); and finally (4) a basal clade with long and spiny spindles, which includes some African species such as Filigorgia angolana and F. schoutedeni as well as other new combinations (all species previously classified as Leptogorgia but not phylogenetically related). The combined set of sclerites of Tobagogorgia (e.g. both asymmetrical and irregularly bent spindles) separates it from the diagnostic characters of related genera such as Muriceopsis and Pinnigorgia. The latter two genera are also profusely branched, including pinnate patterns, whereas T. hardyi has only one or two branches. Externally, T. hardyi looks like some Leptogorgia colonies that branch minimally but it is clear that the sclerites are very different and thus also their phylogenetic divergence.     

Breeding biology of the Pale-bellied Tyrant-manakin Neopelma pallescens (Aves: Pipridae) in south-eastern Brazil

The Pale-bellied Tyrant-manakin (Neopelma pallescens) inhabits semi-deciduous and riparian forests in central-north South America. Contrary to most manakins, there is no evident sexual dichromatism in the species and little is known about its breeding biology. We studied the breeding biology of a colour-banded population of the species from August to December 2016 and from August to October 2017 in the Campus Florestal of the Universidade Federal de Viçosa, south-eastern Brazil. The breeding season extended from early September to late November. The species is promiscuous, with males exhibiting simple courtship displays (exploded leks) in individual arenas. The nest (n = 13) is a cup attached by its top lip between forked branches and is very simple, with a structural layer made with dry grass stems and heads, attached to the branch with spider silk. The outer and lining layers are absent. The mean clutch size was 1.8 eggs (n = 11), which are oval and pale coloured, covered with spots of different shades of brown, often concentrated in the larger pole. Mean egg length and width (± SD) were 21.0 ± 0.9 × 15.8 ± 0.7 mm (n = 14) and the mean weight was 2.8 ± 0.4 g (n = 10). The incubation period could not be estimated, but the nestling period was 15 days (n = 2). The simple percentage of successful nests was 15.4%, with 76.9% of the nests depredated and 7.7% abandoned. This is the first detailed study about the breeding biology of any Neopelma species, providing relevant data for the study of the evolution of life history strategies not only for the genus, but for the whole family Pipridae.     

Two new nematodes,Pseudelzalia longiseta gen. nov., sp. nov. and Paramonohystera sinica sp. nov. (Monhysterida: Xyalidae), from sediment in the East China Sea

Pseudelzalia longiseta gen. nov, sp. nov. and Paramonohystera sinica sp. nov. from subtidal sediment in the East China Sea are described. Pseudelzalia is characterized by 6 labial papillae and 10 cephalic setae, cylindrical buccal cavity, elongate (>2 anal body diameter) spicules, and conico-cylindrical tail devoid of terminal setae. It differs from Elzalia by the absence of terminal setae. Pseudelzalia longiseta sp. nov. is 647–853 μm long, has 7–8 μm long cervical setae, 11–14 μm long caudal setae, 25–41 μm long spicules about 2.1–2.7 anal diameter, and pointed tail-tip. Paramonohystera sinica possesses 12 cephalic setae, a character found in four congeners: Paramonohystera buetschlii (Bresslau and Schuurmans Stekhoven in Schuurmans Stekhoven, 1935, Paramonohystera pilosa Boucher, 1971, Paramonohystera concinna Lorenzen, 1977 and Paramonohystera halerba Fadeeva and Belogurov, 1987. It differs from P. buetschlii by shorter body (933–1023 μm versus 2000–2200 μm); from P. pilosa by the much shorter spicules (79–88 μm versus 167 μm) and narrower head (13–16 µm versus 32 µm); from P.concinna by smooth cephalic setae (versus segmented); and from P. halerba by the absence of two rows of setae on the ventral side of the tail (versus present). Based on the evaluation of nominal species, we recognize 14 valid species and provide an emended diagnosis and a tabular key for Paramonohystera.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:474B8F17-AED7-4078-8176-DFC499B78526     

First record of Monobrachium parasitum Mereschkowsky, 1877 (Cnidaria: Hydrozoa) from Brazil,in the tropical southwestern Atlantic,and its implication for bipolarity concepts

Project HABITATS was recently initiated in the Campos Basin (20.5–24° S), state of Rio de Janeiro, to assess biological impacts of petroleum exploration and exploitation on the continental shelf and slope of Brazil. Among species discovered in benthic samples from the area is the hydroid Monobrachium parasitum Mereschkowsky, 1877, occurring in an epibiotic association with the pelecypod mollusc Mendicula ferruginosa (Forbes, 1844): this is the first report of an association between the two species. Monobrachium parasitum has always been reported from cold waters, and is generally considered bipolar. This report records the occurrence of M. parasitum at lower latitudes, where they have seldom been collected: it is also the first account of this species from South America and the southwestern Atlantic. Moreover, the bathymetric distribution of M. parasitum is extended to a depth of 998 m. No previous records exist of hydroids from the Brazilian continental slope.