Are the funnel-canal organs the ‘campaniform sensilla’ of the shore crab,Carcinus maenas (Decapoda,Crustacea)?

Summary The funnel-canal organs on the dactyls of the shore crab, Carcinus maenas, are innervated by 3–24 sensory cells with unbranched dendrites, which attain a length of 500–1400 m. The outer dendritic segments are enclosed in a dendritic sheath and pass through the cuticle within a canal. Two dendrite types can be distinguished according to ultrastructural criteria: Type I has a long ciliary segment, A-tubules with an osmiophilic core and arms, and a thick ciliary rootlet. Type II possesses only a short ciliary segment and a thin ciliary rootlet. Each funnel-canal organ contains two type-I dendrites. Their ciliary bases appear a few m distal to those of the type-II dendrites (1 to 22 in number). Two inner and two to eight outer enveloping cells belong to a sensillum. The innermost enveloping cell contains a large scolopale. In the second enveloping cell single scolopale rods are present. Thus, the funnel-canal organs are characterized by structural features typical for mechano-sensitive scolopidia, on the one hand, and for chemoreceptors, on the other. Therefore, the funnel-canal organs are very likely bimodal sensilla (contact chemoreceptors). A comparison with other arthropod sensilla shows that cuticular mechanoreceptors of aquatic crustaceans generally exhibit a scolopidial organization.     

Ultrastructure of the larval stemmata,the stemmata nerves and the optic neuropils of the larval cotton bollworm,Heliothis armigera (Hübner) (Lepidoptera : Noctuidae)

Ultrastructure of stemmata (larval eyes), stemmatal nerves, and the optic neuropils of 5th-instar larvae of cotton bollworm, Heliothis armigera (Hübner) (Lepidoptera : Noctuidae), were examined with scanning and transmission electron microscopes. Six stemmata are on each side of the head. Each stemma consists of 7 retinula cells arranged into 2 tiers. Stemmata I and II have 4 distal retinula cells and 3 proximal cells, the other 4 stemmata (III–IV) have 3 distal cells and 4 proximal cells. Stemmata I and IV have a short proximal rhabdom and the rhabdomere of each proximal cell has its microvilli projecting in only one direction. On the other hand, each stemma (in stemmata II–V) has a long proximal rhabdom and the rhabdomere of each proximal cell has microvilli pitched in several different directions relative to the horizontal plane. An axon projects proximally from each retinula cell body. The stemmatal nerve is composed of the 42 retinular axons from all of the 6 stemmata on the same side of the head. Each stemmatal nerve projects to the ipsilateral optic neuropil. Axons from each stemma are in a fasicle (within the stemmatal nerve), which consists of 7 axons, 3–4 of them are thick and terminate synaptically in the proximal neuropil; the others are thinner and terminate in the distal neuropil. Organelles, particularly lysosomes, undergo ultrastructural transformations relative to ambient light levels. The functional significance of abovementioned structures are discussed in light of current knowledge.     

The Status of the Stock and the Current Fishery for the Atka Mackerel,Pleurogrammus monopterygius (Pallas, 1810), in the Olyutorsky–Navarin Area,Bering Sea

Russian Journal of Marine Biology - The dynamics of the Atka mackerel stock in the Olyutorsky–Navarin area in 1994–2019 is inferred from bottom-trawl surveys, fishery statistics,...     

Additions to the knowledge ofUrumaquia robusta (Xenarthra, Phyllophaga, Megatheriidae) from the Urumaco Formation (Late Miocene), Estado Falcön, Venezuela

We describe new remains ofUrumaquia robusta Carlini, Brandoni &; Sänchez, 2006, which significantly improve the knowledge of the species and allow a more precise discussion about the relationships with the rest of the South American Megatheriinae. The new remains (ulna, phalanx, femora, patella, tibia, astragalus, navicular, metatarsals IV–V) described here suggest close affinities of this taxon with the species ofPyramiodontherium and withMegatheriops rectidens, based on morphological similarities of the ulna (length, gracility), femur (general morphology, shape of the medial margin), and astragalus (angle between the discoidal and odontoid facets). In fact, the shape of femoral medial margin is a shared derived character amongUrumaquia, Pyramiodontherium andMegatheriops. However, and despite the increasing information concerning Tertiary species, their phylogenetic relationships are only partially understood.     

Long-term development of the crustacean plankton in the Saidenbach Reservoir (Germany) – changes,causes, consequences

The rates of development and food intake of the copepod Temora longicornis (Müller) were studied using artificial blooms of Phaeocystis globosa Scherffel under different conditions of nutrient limitation. Mesocosms with 800 l of natural seawater were manipulated by inoculation with cultured P. globosa and by addition of nitrogen and/or phosphorus, to obtain N- or P-limited blooms of P. globosa. During development and ageing of these blooms, water from the mesocosms was used as medium for incubation of nauplii of T. longicornis. Only moderate rates of naupliar development as well as high rates of mortality were observed, irrespective of major differences of nutrient conditions and density of P. globosa. Grazing by the nauplii on P. globosa seemed to be low, suggesting a low food quality of this alga at all physiological conditions studied. The results of this study indicate a low capability of T. longicornis nauplii for control of nuisance algal blooms caused by P. globosa.     

The cytology,histochemistry, and ultrastructure of the cell types found in the digestive gland of the slug,Agriolimax reticulatus (Müller)

Summary Four cell types have been identified in the digestive glands from light and electron microscope studies. The possible functions of each cell type are discussed.Thin cells are undifferentiated. Calcium cells contain spherules of calcium salts which have a characteristic ultrastructure. Different protein granules are found apically. Digestive cells are present as two distinct forms. One form is believed to be absorbing food material and digesting it intracellularly, and the other form is a secreting cell. Both forms contain green and yellow granules and histochemistry shows these granules to be distinct. Protein granules also occur apically.Excretory cells are distinguished by having a large central vacuole containing excretory granules. Histochemistry shows these granules, like the yellow granules of digestive cells, to be composed mainly of lipofuscin.It is suggested that digestive cells form excretory cells.     

On the muscles of expression in the geladaTheropithecus gelada (Rüppell) (primates,Cercopithecidae)

Musculature innervated by the N. facialis inTheropithecus gelada (Rüppell) is patterned on broad lines in agreement with related genera of catarrhine monkeys, but presents some specializations and divergences in detail. Noteworthy is the extension to the labial margins superficially of the combined levator labii superioris and zygomaticus in the upper and the pars mandibularis of trachelo-platysma in the lower lip. A specialization of the medial fibres of levator labii superioris forms a sling-like structure within the upper lip and serves to implement the lip-flip gesture characteristic of the genus. Its antagonist is the orbicularis oris. Special features of all other facialis muscles are considered.Abbreviations ABD Anterior belly of digastricus - AE Arteria facialis - ALS Arteria labialis superior - ANL Arteria lateralis nasi - AP Auricularis posterior - APA Arteria auricularis posterior - AS Arteria auricularis superior - A.Se. Arteria septi nasi - A.Sy. Arteria symphysialis - BP Buccal pouch - LAO Depressor anguli oris - FTA Fronto-temporo-auricularis - GLI Glandulae labialis inferiores - GLS Glandulae labialis superioris - LAO Levator anguli oris - LG Artery to labial glands - LLAN Levator labii superioris alaeque nasi - LLS Levator labii superioris - M Masseter - MM Musculus mentalis - NP Notoplatysma - O Occipitalis - OO Orbicularis oris - O.Oc Orbicularis oculi - P Procerus - SH Sterno-hyoideus - TP Trachelo-platysma - VL Vena labialis communis - VP Venous plexus of dorsum nasi - ZM Zygomaticus minor - Zy Zygomaticus     

Cleft,Crevice, or the Inner Thigh: ‘Another Place’ for the Establishment of the Invasive Barnacle Austrominius modestus (Darwin, 1854)

The proliferation of anthropogenic infrastructure in the marine environment has aided the establishment and spread of invasive species. These structures can create novel habitats in areas normally characterised as void of suitable settlement sites. The habitat requirements of the invasive acorn barnacle Austrominius modestus (Darwin, 1854) were assessed using a novel sampling site at Crosby Beach, Liverpool. Austrominius modestus has spread rapidly around the UK since its initial introduction, becoming locally dominant in many estuarine areas including the Antony Gormley art installation, ‘Another Place’, at Crosby Beach. The installation consists of 100 replicate solid cast-iron life-size human figures, located at a range of heights on the shore. We recorded the distribution and abundance of A. modestus present on all of the statues at various positions during the summer of 2006. The positions varied in location, exposure, direction, and rugosity. Although parameters such as rugosity and exposure did influence patterns of recruitment, they were less important than interactions between shore height and direction, and specific location on the beach. The addition of a suitable substrate to a sheltered and estuarine region of Liverpool Bay has facilitated the establishment of A. modestus. Understanding the habitat requirements of invasive species is important if we are to make predictions about their spread and the likelihood of invasion success. Austrominius modestus has already become locally dominant in some regions of the UK and, with projections of favourable warming conditions and the global expansion of artificial structures, the continued spread of this species can be expected. The implications of this on the balance between native and invasive species dominance should be considered.     

Properties of the β-d-glucosidase (cellobiase) from the wood-rotting fungus,Coriolus versicolor

Summary Structural and kinetic parameters of the -d-glucosidase (cellobiase, -d-glucoside glucohydrolase) from Coriolus versicolor have been determined. It is a high molecular weight glycoprotein (300,000 d) composed 10% by weight of protein, 90% by weight of carbohydrate in which glucose is the primary hexose sugar. The K_m for 4-nitrophenyl--d-glucopyranoside (4 NPG) and cellobiose are 0.276 and 2.94 mM respectively at pH 4.5 and 40°. d-Glucose is a competitive inhibitor with a K_i of 1.8 mM with 4 NPG as substrate, and at high concentrations, cellobiose exhibits a substrate inhibition effect on the enzyme, so negating attempts to overcome the competitive inhibition of glucose by increasing the concentration of the substrate.     

Ionic regulation of the haemolymph in the larvae of the dragonfly Aeshna cyanea (Müller) (Odonata, Anisoptera).

The ionic regulation of the haemolymph of larvae of Aeshna cyanea (Müller) was studied by means of two types of experiments. In the first the change in internal ionic composition was followed as a function of the time spent in a given experimental medium. These experiments led to the conclusion that: 1. the haemolymph composition does not change when larvae are starved in tap water for 10 days; 2. the haemolymph ionic concentrations (Na and Cl) have initial marked increase when the animals are kept in hypertonic media of diluted sea water; after 80 hours however, both concentrations stay constant. In a second series of experiments the internal ionic concentration was compared to a series of different concentrations of external media. From this, the relation between the internal and external ionic concentration was elaborated : in hypotonic media the internal Na and Cl concentrations stay constant, in hypertonic media there is a parallelism between the increase of the external concentration and haemolymph concentration, the internal Na concentration being always slightly hypertonic, the Cl concentration markedly hypotonic. Finally, when larvae are placed in glass distilled water, the internal Na and Cl concentrations begin to decrease after 60 hours.     

The roles of the Chantransia phase of Lemanea (Lemaneaceae,Batrachospermales, Rhodophyta) and of the ‘Mushroom’ phase of Himanthalia (Himanthaliaceae,Fucales, Phaeophyta)

Summary

The life cycle of the Batrachospermales (freshwater florideophyte red such as Batrachospermum, Lemanea) is a shortened variant of the ‘normal’ marine florideophyte life cycle. The perennial Chantransia diploid phase is microscopic and encrusting. Each winter it produces one or more semi-erect haploid gametophytes by vegetative meiosis. Gamete production and fertilization is followed by production of diploid carposporophytes; these produce diploid carpospores which disperse, and regenerate the Chantransia phase. The question of the extent to which the Chantransia phase contributes resources to the gametophyte was approached by physiological-hydrodynamic modelling. These computations suggest that the photosynthetic rates in situ on an area basis are 20 times greater for the gametophyte than the Chantransia phase; this agrees with the observed ratios of peak biomass. The conclusion is that the Chantransia phase has a negligible role in provisioning the growing gametophyte, and that the role of the Chantransia phase is to occupy space with living biomass throughout the year, including exposure at summer drawdown, and (perhaps) by dispersal via production of monospores. A similar conclusion is arrived at on the basis of biomass data for the role of the perennial ‘mushroom’ phase of the semelparous marine Fucalean brown alga Himanthalia elongata in relation to the short-lived but much larger reproductive receptacles.     

Comparison of the directionality of the halogen,hydrogen, and lithium bonds between HOOOH and XF (X = Cl,Br, H,Li)

Detailed electrostatic potential (ESP) analyses were performed to compare the directionality of halogen bonds with those of hydrogen bonds and lithium bonds. To do this, the interactions of HOOOH with the molecules XF (X?=?Cl, Br, H, Li) were investigated. For each molecule, the percentage of the van der Waals (vdW) molecular surface that intersected with the ESP surface was used to roughly quantify the directionality of the halogen/hydrogen/lithium bond associated with the molecule. The size of the region of intersection was found to increase in the following order: ClF?<?BrF?<?HF?<?LiF. The maximum ESP in the region of intersection, V _{S, max}, was observed to become more positive according to the sequence ClF?<?BrF?<?HF?<?LiF. For ClF and BrF, the positive electrostatic potential was concentrated in a very small region of the vdW molecular surface. On the other hand, for HF and LiF, the positive electrostatic potential was more diffusely scattered across the vdW surface than for ClF and BrF. Also, the optimized geometries of the dipolymers HOOOH···?XF (X?=?Cl, Br, H, Li) indicated that halogen bonds are more directional than hydrogen bonds and lithium bonds, consistent with the results of ESP analyses.

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Graphical abstract Electrostatic potential (ESP) contour maps in the xz plane of ClF and BrF

     

Research ethics: the case with the tule (kuna), Urabbá, Colombia

An ethical analysis was performed during the development of a research project titled "Culture, nourishment and malaria in the Kuna aboriginals of Urabá, Colombia." This project had 2 objectives; (1) to investigate the prevalence of malaria and its relationship with hypovitaminosis A and nutritional status, and (2) to understand the community's conceptions and practices towards malaria. The current paper summarizes reflections concerning the application of ethical principles and moral values during the course of the malaria research project. Two intercultural relationships were clearly defined: the culture of the Tule (Kuna) Indians, with a traditional medical system, and the culture of the research group, focused on the biomedical model. The rationale and the discussion proposed during the writing of the project proposal was presented as well as the dilemmas that developed during the project within the communities. These problems required rapid decision-making in situations for which the scientists had not been adequately prepared. A need was indicated for application of ethical principles to permeate the analysis throughout the research process in a horizontal manner, such that the human dignity of the participants and the ethnicity of the community are preserved above the purposes of the project. In the research process, mediation between the ethics of conviction and the ethics of consequences must take precedence, with both outcomes tied to an informed consent in place during the process. The establishment of national and local research ethics committees was indicated as necessary to preserve the lifestyle and culture of the ethnic groups. These values were seen as endangered given the trading pressures and health policies in a globalized world.     

Review of the western palaearctic Ichneumon-flies of the genus Rhorus Förster, 1869 (Hymenoptera,Ichneumonidae: Ctenopelmatinae). II. The species of the punctus,longicornis, chrysopygus,and substitutor groups,the species with the black metasoma and some others

The Western Palaearctic species of Rhorus with the black metasoma and all the species of 4 speciesgroups (the punctus, longicornis, chrysopygus, and substitutor) are revised. Fourteen new species from the Western Palaearctic Region (mainly from Europe) are described: Rh. arkhyz sp. n., Rh. avacha sp. n., Rh. boreator sp. n., Rh. brevigena sp. n., Rh. gauldi sp. n., Rh. humalai sp. n., Rh. jussilai sp. n., Rh. laricis sp. n., Rh. olenek sp. n., Rh. pristiphorae sp. n., Rh. romani sp. n., Rh. suecicus sp. n., Rh. ucrainicus sp. n., and Rh. xanthopygus sp. n. A key to 40 species is given.     

Reproductive biology of the marine catfish,Genidens genidens (Siluriformes,Ariidae), in the Jacarepaguá Lagoon system,Rio de Janeiro,Brazil

Synopsis Genidens genidens was sampled at the Jacarepaguá Lagoon system (23° S, 43° W), Rio de Janeiro State, Brazil, using cast nets and beach seines, to study its reproductive biology. Spawning period extended from October to February, but was more intense from December to January, coinciding with high surface water temperature and low salinity in the area. After spawning, males mouthbrood the eggs for two to three months until development is completed. Mean length at first maturity for females was approximately 180 mm TL, and at 250 mm TL, all females were mature. Batch fecundity was very low, ranging from 7 to 30 eggs for fish with 170 mm TL (37.0 g TW) to 228 mm TL (104.0 g TW), respectively, and was linearly related to fish total length and total weight. Sexual dimorphism starts after sexual maturity, with females having relatively longer pelvic fins than males. Both sexes exhibited very low condition during the spawning season, probably due to changes in feeding activity related to the reproductive cycle. A strong predominance of males during the main spawning/brooding period suggests that females migrate from the area after spawning is completed.Present address: Virginia Institute of Marine Science, School of Marine Science, The College of William and MaryGloucester Point, VA 23062, U.S.A.     

Physiological, Endocrine, and Genetic Bases of Anadromy in the Brook Charr, Salvelinus Fontinalis, of the Laval River (Québec, Canada)

Brook charr, Salvelinus fontinalis, often display alternate life history styles in coastal areas. In the Laval River, some brook charr remain freshwater residents, while others undergo seasonal migrations between freshwater and saltwater environments. In the present paper, we examined physiological (electrolyte concentrations, gill Na⁺, K⁺-ATPase activity, and thyroid hormone levels) as well as genetic differences (neutral genetic markers) between anadromous and river-resident fish from the Laval River. We also examined how artificial rearing conditions affected seasonal variations in the osmoregulatory physiology of a domestic strain derived from wild anadromous fish. Sympatric anadromous and resident forms of brook charr of the Laval River exhibited differences in gill Na⁺, K⁺-ATPase activity, plasma thyroxine (T₄), and triidothyronine (T₃) concentrations. In domestic anadromous charr, rearing conditions during development had no negative impact on osmoregulatory ability or on gill Na⁺, K⁺-ATPase activity. These results argued for an important hereditary component of gill Na⁺, K⁺-ATPase activity. However, the spring increase in T₄ was present only in wild fish. Significant differences observed at microsatellite loci further suggested that at least some level of reproductive isolation may have occurred between anadromous and resident charr in the Laval River.