Medusoid release and spawning of Macrorynchia philippina Kirchenpauer, 1872 (Cnidaria,Hydrozoa,Aglaopheniidae)

The life cycle of the aglaopheniid Macrorynchia philippina Kirchenpauer, 1872, is re-described from examination of live specimens collected from Réunion Island, Indian Ocean. Fertile colonies were collected on the outer slope of the coral reef and medusoid release happened a few hours later. Video sequences were recorded. Colonies were hermaphroditic: each phylactocarp contained one female and one male gonotheca. Sexual dimorphism was remarkable: sex could be recognized by colour, the female being red ochre, including about 40 oocytes disposed in a mosaic feature, and the male yellow ochre, having a homogeneous mass of spermatozoa. The blastostyle ran all around the gonangium near the closure of the two valves of the gonotheca, forming gubernacula. A ring of refringent corpuscles was clearly visible near the apex. Medusoids were indistinguishable inside the gonotheca. Male and female medusoids were released simultaneously at gamete maturity. Medusoid release involved the basal rupture of the blastostyle and the rupture of the links between the ectoderm surrounded the medusoid (the mantle), including the blastostyle (the mantle), and the gonothecal perisarc. While the two valves of the gonotheca were pushed and drew aside, the medusoid emerged by slipping out of the mantle that ruptured distally, forming a sheath; the bell of the medusoid did not contract. Immediately after emergence, quick and strong contractions of the bell allowed the medusoid to swim and induced spawning by breaking the ectoderm surrounding the gametic mass around the spadix. Spawning lasted only a few minutes: both oocytes and spermatozoa were expelled at each contraction. Spent medusoids remained alive only about 2 h. External fertilization gave rise to planulae 1 day later.     

Notes on the life histories of Boergesenia and Valonia (Siphonocladales,Chlorophyta)

Life history studies were carried out with isolates of Boergesenia forbesii (from Western Australia), Valonia fastigiata (Hawaii) and V. utricularis (Canary Islands, Mediterranean Sea) cultivated under laboratory conditions. Ploidy levels of nuclei were identified by micro spectrophotometric DNA content measurements after Feulgen staining. Fundamentally, the life history in both genera is diplohaplontic. Autodiploidization phenomena have been observed favoring the diploid generation. In contrast to other genera of the Siphonocladales s. str. producing biflagellate diploid zoospores (e.g. Ernodesmis, Boodlea), Valonia develops haploid and diploid zoospores with four flagella. No diploid zoospores were observed in Boergesenia.     

Reproduction of the colonial hydroid Obelia geniculata (L., 1758) (Cnidaria,Hydrozoa) in the White Sea

Populations of the colonial hydroid Obelia geniculata in the White Sea reproduce asexually by frustule formation. Young medusae appear in the plankton during July and August. The number of medusae rarely exceeds 36 per m³, and the average number varies every year from 0.4 to 10 per m³. The size of medusae is smaller than reported from other regions. The umbrella of the largest recorded medusa was only 0.57 mm in diameter and the specimen had just 35 tentacles. Only a few mature medusae were found during the study. The colonies in the White Sea are epiphytic and grow only on laminarian thalli. At the beginning of July there are no colonies on thalli from the upper subtidal zone. By the end of August, colonies of O.␣geniculata had increased in density to 30 per m². Hydroid recruitment was attributed to active frustule production by colonies living below that zone. The frustules detach from the stems of the hydroids and are found in plankton. Production of frustules on branches occurs continuously during colony growth until water temperatures climb above 0 °C. We found that water temperature in this Arctic environment is generally too low for medusa maturation and planula development in the species. Propagation by frustule formation is the principal means of reproduction in Obelia geniculata within the White Sea, and this phenomenon accounts for the species being a dominant epiphyte on laminarian thalli there.     

Notes on the floral morphology in Vivianiaceae (Geraniales)

The functional floral morphology of the three genera of Vivianiaceae (= Ledocarpaceae, Geraniales), Rhynchotheca, Viviania and Balbisia, is compared. Likely pollination mechanisms are inferred from morphology and field observations. The flowers of Viviania are nectariferous and apparently zoophilous with nectar as the (primary) pollinator reward. Balbisia has pollen flowers without nectaries, its showy corolla indicates that it is also zoophilous with pollen as sole pollinator reward; bees were observed as flower visitors. One taxon (B. gracilis) may be anemophilous. Rhynchotheca has flowers without petals, with large, pendulous anthers and lacks nectaries. It shows synchronous mass flowering in its natural populations and is evidently anemophilous. A comparison with other Geraniales shows that nectar flowers with small anthers are likely the ancestral condition in Vivianiaceae. This suggests that the pollen flowers with larger anthers of Balbisia and Rhynchotheca may represent an apomorphic condition. The documentation of pollen flowers and anemophily in Vivianiaceae expands the range of known floral and pollination syndromes in Geraniales.     

The benthic phase of the life cycle ofParapenaeus longirostris (Crustacea,Decapoda, Penaeidae) along the Mediterranean coast of Israel

The population ofP. longirostris along the Mediterranean coast of Israel spends the benthic phase of its life cycle (from body size over 15 mm) on muddy bottom deeper than 45 m. New age groups are recruited within the depth zone of 45–300 m and migrate in both inshore and offshore directions. Inshore migration is limited by unsuitable sandy ground. The limiting line for offshore migration was not found.An age group could be detected during one year within a body size range of TL = 40 mm to TL = 84.5 mm for males and to TL = 102.5 mm for females. Reproductive activity in shallow water, down to a depth of 73 m, takes place during the whole year, while in depths of 150–300 m there is an arrest of reproductive activity from June to August.     

Notes on the biology of the freshwater planarian Dugesia bengalensis (Platyhelminthes Turbellaria Tricladida)

Dugesia bengalensis was described by Kawakatsu (Kawakatsu et al., 1983) from specimens collected in West Bengal. We have been studying populations from many different localities in Santiniketan and adjoining areas of West Bengal and can provide additional biological information.The species is hermaphroditic, and its breeding season was found to occur usually between October and March when the winter temperature falls below 25 °C. Outside of the breeding season, D. bengalensis is capable of asexual reproduction by binary fission (Mahapatra et al., 1987).Development of the reproductive organs appeared to be from neoblasts and other mesenchymal cells and, therefore, to be like that typical of other triclads with the exception that some of the neoblasts used for the reproductive tissue appeared to be derived from the intestinal region (Ghosh, 1988; cf. Teshirogi, 1986).During copulation, the partners were oriented in the same direction and not in a head-to-tail position as has been reported (Hyman, 1945) for some planarians.The oval, stalked cocoons were laid in marshy places, and during the period of summer (usually from April to June) they lay dormant in the sandy soil until the onset of the monsoon rains. Then, typically three or four months after they were laid, the cocoons hatched to yield three or four young, a remarkably low number for freshwater triclads (cf Ball & Reynoldson, 1981).     

Notes on the variation,geographical distribution and ecology ofEuastrum insulare var.basichondrum (Chlorophyta,Desmidiaceae)

Euastrum insulare var.basichondrum, morphologically taking an intermediate position in respect ofCosmarium trilobulatum var.basichondrum andEuastrum bipapillatum, appeared to exhibit such a wide range of variation that it may be considered identical to the other two above-mentioned taxa. This taxon, after having been studied with both light- and scanning electron microscopy, is re-diagnosed. This alga occurs in wet moss cushions in weakly acid to neutral environments. The relation between such a terraqueous habitat and the principally arctic-alpine distribution and a conceivably associated process of speciation is discussed.     

Distributional ecology and behaviour of the early life stages of the box-jellyfish Chironex fleckeri

Laboratory observations on reared life stages of Chironex fleckeri (Cubozoa: Chirodropidae) have been combined with field sampling and observations to outline the life cycle of the species and the spatial and temporal distribution of populations in Queensland, Australia. A seasonal alternation of polypoid and medusoid generations from winter to summer respectively is accompanied by a shift in preferred habitat from tidal estuaries to the open eulittoral zone. The system appears to be constrained by predictable fluctuations in the suitability of the alternate habitats to their resident generations. Observations on behaviour, feeding, physiological tolerances, and sexual and asexual reproduction provide insights into the adaptiveness of this pattern.     

A mutant ofDunaliella parva CCAP 19/9 leaking large amounts of glycerol into the medium

A mutant of the halotolerant green algaDunaliella parva, which leaks large amounts of intracellular glycerol into the surrounding medium, was isolated. The mutant has potential applications in the commercial production of glycerol on a large scale since there is no need to extract glycerol from the cells. The mutant was compared with the wild type and it was found that, despite the leakage of glycerol, the mutant showed the same growth rate as the wild type. However, when the rates of oxygen evolution and uptake and intracellular starch content between mutant and wild type were compared at high salinity, considerable differences were found.     

Instar sizes,life cycles,and food habits of five Rhyacophila (Trichoptera: Rhyacophilidae) species from the Appalachian Mountains of South Carolina,U.S.A.

The larval head widths at each instar, life cycles, and food habits of late instars were determined for five species of Rhyacophila from two Appalachian mountain streams in South Carolina, U.S.A. Rhyacophila acutiloba Morse & Ross was univoltine with two cohorts, one emerging in the spring and another presumably emerging in early autumn. Rhyacophila fuscula (Walker), R. nigrita Banks, and R. carolina Banks were apparently multicohort, univoltine species with extended flight periods. Rhyacophila minor Banks was univoltine with a spring emergence. All species were predaceous and consumed mainly Plecoptera nymphs and Trichoptera larvae.     

Coulonia parva n. sp., a new species of Astropectinidae (Asteroidea; Echinodermata) from the Santonian (Upper Cretaceous) of Sierra de Montsech (southern Pyrenees, Spain)

A new astropectinid sea star,Coulonia parva n. sp., is described from the Santonian of the Sierra de Montsech, northern Spain. The single specimen shows part of a rather weathered ventral side. It is characterized by comparatively long arms (R/r approx. 3/1), with one row of actinals reaching far into the arms; inferomarginals on the interbrachial arc have deep fasciolar grooves that are less developed on the arms; there are no larger spines on adambulacrals and probably also on inferomarginals. Based on presence of deep marginal fascioles,C. parva n. sp. is inferred to have shared the capability for self-burial with the relatedC. platyspina Hess &Blake.      

Distribution and life cycle of the North American Spionid polychaeteMarenzelleria viridis (Verrill, 1873) in the Ems estuary

In 1983 the first specimens of the North American spionid polychaeteMarenzelleria viridis were found along the European mainland shore in the Ems estuary. Since then, this polychaete has spread over several estuaries around the North Sea and the Baltic. In the inner part of the Ems estuary juveniles were predominantly present in muddy sediments high in the intertidal zone; in more sandy sediments at higher salinities juveniles and adults co-occured. Detailed information was obtained at a muddy and at a sandy station. Gametes were present in the coelomic fluid from November through March. In May new recruits were found in the sediment samples, reaching densities of over 10⁵ M⁻² at the muddy station, andc. 2000 m⁻² at the sandy station. During summer, densities decreased at the muddy station, coinciding with a density increase at the sandy station, suggesting migration of juveniles from a nursery to the adult habitat. Cage experiments showed that the decrease of juveniles at the muddy station could be attributed to migration and not to mortality due to predation. At the sandy habitat palps and anterior parts ofM. viridis made up 4–11% of the stomach content of juvenile plaice (Pleuronectes platessa). In juvenile flounder (Platichthys flesus) only in Aprilc. 10% of the stomach content consisted ofM. viridis. During 1983–1990 increasing densities ofM. viridis at the sandy habitat coincided with a reduced abundance ofNereis diversicolor, however, this inverse relationship was not found to be statistically significant. Density fluctuations ofM. viridis andCorophium volutator showed a significant positive relationship, the cause of which is not yet understood.     

The life-cycle,ecology and host specificity of the freshwater leech Alboglossiphonia polypompholyx (Glossiphoniidae) in Egypt

Alboglossiphonia polypompholyx spends most of its life cycle endoparasitic in the mantle cavity of the snail Bulinus truncatus — possibly its only host. Adult A. polypompholyx leaves the snail about one month before the commencement of egg-laying. Hatching occurred after about 15 d and after brooding on the venter of the parent for 7–10 d, the young briefly become free-living before entering the mantle cavity of B. truncatus. Within the mantle cavity, A. polypompholyx feeds and grows for 16–20 weeks before leaving the snail as adults. In the field and in laboratory experiments, adult leeches left the snails in August/September and January with cocoons produced in October/November and February/March, respectively. Free-living adult leeches do not feed and die 1–2 months after the cessation of brooding.     

The photosynthesis of Dunaliella parva Lerche as a function of temperature,light and salinity

The photosynthetic behaviour of Dunaliella parva Lerche from the athalassic lagoon of Fuente de Piedra (Málaga, Southern Spain) was studied experimentally at three NaCl concentrations (1, 2 and 3 M), five temperatures (15, 23, 31, 38 and 42°C) and nine different irradiances between 82 and 891 mol m^–2 s^–1. Results are analyzed to define the best growing conditions for the algae. D. parva shows the highest photosynthetic rates at a NaCl molarity of 2 M, under a moderate light intensity (600 mol m^–2 s^–1) at 31°C. Above this light intensity a clear photoinhibition of the photosynthesis was found at 2 M and 3 M of NaCl. D. parva is a halotolerant and a thermoresistant species as evidenced by its net photosynthesis rate and positive values of oxygen evolution at 42°C.Two methods for modelling photosynthesis vs. irradiance curves are discussed. The first is a single model, based on third-order polynomial equations, and the second is double model, based on hyperbolical Michaelis-Menten type functions and negative exponential to define photoinhibition.     

Pleoanamorphic life cycle ofExophiala (Wangiella) dermatitidis

The anamorph life cycle of the black yeastExophiala (Wangiella) dermatitidis is described. The fungus is dimorphic, yeast cells being the prevalent form of propagation. The fungus is strongly hydrophilic, probably completing its anamorph life cycle in submersion. Adaptation to dry conditions is slow. Types of conidiogenesis comprise annellidic, phialidic and sympodial reproduction, in addition to isotropic development. Phialoconidia fail to germinate under the conditions tested, and thus may have a function other than dispersal. Sterile, multicellular bodies resembling aCapronia teleomorph are described.     

The life cycle of Laodicea indica (Laodiceidae,Leptomedusae, Cnidaria)

The life cycle of Laodicea indica is described. In the Bismarck Sea this species shows a normal alternation of generations in the wet season; but in the dry season the cycle is contracted, and planulae give rise to gonothecae without formation of a hydroid colony. Medusae are liberated about 3 d after planula settlement. This life cycle pattern is previously unreported in hydromedusae. The possible adaptive value of such a life cycle and the evolution of polyp reduction in hydromedusan life cycles are discussed.     

Description of the larva of <Emphasis Type="Italic">Curteria</Emphasis> Southcott, 1961 (Acari,Parasitengona, Erythraeidae) with notes on biology and life cycle

The larvae of Curteria episcopalis (C.L. Koch, 1837) and Curteria southcotti Gabryś, 1992, are described based on specimens reared in the laboratory. Pedroerythraeus Haitlinger, 2004 is considered a junior synonym of Curteria. Data on habitat specificity and phenology of the species as well as on development of eggs into larvae are given.     

Holostephanus metorchis (Digenea: Cyathocotylidae) from chicks experimentally infected with metacercariae from a fish, Pseudorasbora parva, in the Republic of Korea

Holostephanus metorchis (Digenea: Cyathocotylidae) is a parasite of birds, transmitted by freshwater fishes. H. metorchis adults were recovered from chicks experimentally infected with metacercariae collected from freshwater fishes, Pseudorasbora parva. The metacercariae were oval, surrounded with thick fibrous capsules. In adult flukes, the holdfast organ occupied the ventral concavity, and the anterior testis did not reach the level of the ventral sucker. Based on these morphological characteristics, these flukes were identified as H. metorchis.     

Taxonomic implications of life cycle and basidium morphology of Ochropsora ariae and O. nambuana (Uredinales)

Ochropsora ariae was found to host-alternate between Anemone pseudo-altaica and Aruncus dioicus var. tenuifolius and Ochropsora nambuana between Anemone flaccida and Elaeagnus multiflora var. hortensis in Japan. Both species produced a sessile, thin-walled, cylindrical probasidium (teliospore), which turned into a four-celled metabasidium by continuous apical elongation of the probasidium. Several probasidia of O. nambuana were produced from a basal basidiogenous cell in a sorus hymenium. Life cycle and probasidium/metabasidium morphology showed the taxonomic identity of Ceraceopsora elaeagni with O. nambuana. Developmental morphology of the basidium found in the two Ochropsora species raised a question against the taxonomic separation of Ochropsora and Aplopsora.