Reproductive cycle of the winged pearl oyster,Pteria penguin (Röding 1793) (Pteriidae) in north-eastern Australia

The spawning cycle of the winged pearl oyster, Pteria penguin, was studied at Orpheus Island, north-eastern Queensland to observe seasonal changes in gonad development, mean oocyte diameter and sex ratio over time. A total of 201 oysters were collected over 10 sampling periods, approximately every 5–6 weeks (mean?=?20 oysters/sample). Histological analysis of gonads showed that spawning activity occurred mainly through the austral mid-spring to late summer (November to March), when mean monthly water temperature ranged between 27.5°C and 29.4°C. There was a primary spawning peak at the beginning of the spawning season in December, followed by a secondary peak in March. Mean oocyte diameter (µm) was highest during the warmer months, ranging from 31.2?±?2.4 in November to 36.2?±?3.2 in March, and sex ratio analysis showed the percentage of females in the population also peaked between 30% and 50% during this period.     

The Seasonal Aggregation of Whale Sharks at Ningaloo Reef, Western Australia: Currents, Migrations and the El Niño/ Southern Oscillation

Whale sharks, Rhincodon typus, seasonally aggregate in coastal waters off Ningaloo Reef, Western Australia. We review the oceanographic setting of the region and present evidence that such aggregations form as a result of migratory behavior associated with climatic and oceanographic processes. We utilise records of whale shark abundance collected at Ningaloo Reef from dedicated searches by boat and aircraft and from log sheets recorded by the tourism industry. Measures of whale shark abundance derived from log sheet data sets were moderately correlated with the Southern Oscillation Index and weakly correlated with coastal sea level, an index of the strength of the Leeuwin Current, and sea surface temperature over the period 1993 to 1998. Abundances of whale sharks derived from boat searches from 1983 to 1992 were also correlated with fluctuations in the Southern Oscillation Index, except during a three year period from 1988 to 1990. We conclude that, at least in some years, there appears to be a link between the abundance of aggregating whale sharks and the physical and biological oceanography of the region, with greater whale shark numbers in La Niña years. The lack of correlation in other years may be due to a combination of uneven quality of data and/or aggregations occurring in response to a complex interaction between the physical and biological oceanography of the region.     

Do they stay or do they go? Acoustic monitoring of whale sharks at Ningaloo Marine Park,Western Australia

Whale sharks Rhincodon typus were monitored via acoustic transmitters at the northern end of Western Australia's Ningaloo Marine Park to establish the extent to which the species inhabits the region beyond the whale‐shark ecotourism industry season, which usually extends from March to August in each year. Despite the vast majority (c. 98%) of photographic submissions of R. typus from Ningaloo Reef being between March and August, acoustic detections from the tagged R. typus at Ningaloo were recorded in all months of the year, but do not preclude the occurrence of extended absences. It is concluded that as a species, R. typus occurs year round at Ningaloo, where it generally remains in close proximity to the reef edge, but that some individuals move outside of the detection range of the array for extended periods.     

Which Environmental Factors Predict Seasonal Variation in the Coral Health of Acropora digitifera and Acropora spicifera at Ningaloo Reef?

The impact of physico-chemical factors on percent coral cover and coral health was examined on a spatial basis for two dominant Acropora species, A. digitifera and A. spicifera, at Ningaloo Reef (north-western Australia) in the southeast Indian Ocean. Coral health was investigated by measuring metabolic indices (RNA/DNA ratio and protein concentration), energy levels (lipid ratio) and autotrophic indices (chlorophyll a (chl a) and zooxanthellae density) at six stations during typical seasons (austral autumn 2010 (March and April), austral winter 2010 (August)) and during an extreme La Niña event in summer 2011 (February). These indices were correlated with 15 physico-chemical factors (measured immediately following coral sampling) to identify predictors for health indices. Variations in metabolic indices (protein concentration and RNA/DNA ratio) for A. spicifera were mainly explained by nitrogen, temperature and zooplankton concentrations under typical conditions, while for A. digitifera, light as well as phytoplankton, in particular picoeukaryotes, were important, possibly due to higher energy requirement for lipid synthesis and storage in A. digitifera. Optimum metabolic values occurred for both Acropora species at 26–28°C when autotrophic indices (chl a and zooxanthellae density) were lowest. The extreme temperature during the La Niña event resulted in a shift of feeding modes, with an increased importance of water column plankton concentrations for metabolic rates of A. digitifera and light and plankton for A. spicifera. Our results suggest that impacts of high sea surface temperatures during extreme events such as La Niña may be mitigated via reduction on metabolic rates in coral host. The high water column plankton concentrations and associated low light levels resulted in a shift towards high symbiont densities, with lower metabolic rates and energy levels than the seasonal norm for the coral host.     

Dynamics of an outbreak population of Acanthaster planci at Lizard Island, northern Great Barrier Reef (1995–1999)

Despite their significant influence on coral reef ecosystems, causes of population outbreaks of crown-of-thorns starfish (Acanthaster planci L.) are still poorly understood. Essentially, outbreaks of A. planci could arise from either (1) a single mass recruitment event or (2) the progressive accumulation of starfish from multiple cohorts. This study explored fine-scale variation in the size, distribution, and abundance of A. planci, during an outbreak at Lizard Island in the northern Great Barrier Reef, to assess the mechanism by which the outbreak occurred. Densities of A. planci around Lizard Island increased very gradually from October 1994 until December 1996, then remained at around 1.0 starfish per 200 m² until June 1998. The population of A. planci comprised individuals ranging in size from 11-cm to 62-cm diameter, representing individuals from multiple (at least four) different cohorts. These data suggest that the outbreak of A. planci at Lizard Island resulted from a prolonged build-up in starfish numbers through multiple successive recruitment events. This study shows that outbreaks of A. planci may arise independently of any sudden or substantial increase in rates of recruitment, such that any factor(s) responsible for the initial onset of outbreaks are likely to be very subtle and difficult to detect.     

Changes in coral assemblages during an outbreak of Acanthaster planci at Lizard Island, northern Great Barrier Reef (1995–1999)

Population outbreaks of crown-of-thorns starfish (Acanthaster planci L.) represent one of the most significant biological disturbances on tropical coral reefs and have the potential to devastate coral communities, thereby altering the biological and physical structure of reef habitats. This study reports on changes in area cover, species diversity and taxonomic composition of corals during an outbreak of A. planci at Lizard Island, in the northern Great Barrier Reef, Australia. Mean coral cover declined by 28.8% across ten locations studied. However, densities of A. planci, and their effects on local coral assemblages, were very patchy. Declines in coral cover were mostly due to the selective removal of certain coral taxa (mainly Acropora and Pocilloporidae corals); such that the greatest coral loss occurred at locations with highest initial cover of preferred coral prey. Most notably, coral assemblages in back-reef locations were transformed from topographically complex staghorn Acropora-dominated habitats, to relatively depauperate assemblages dominated by alcyonacean soft corals. Although coral loss was greatest among formerly dominant taxa (especially Acropora), effects were sufficiently widespread across different coral taxa, such that overall coral diversity tended to decline. Clearly, moderate outbreaks of A. planci have the potential to greatly alter community structure of coral communities even if they do not devastate live corals. Recovery in this instance is expected to be very rapid given that all coral taxa persisted, and effects were greatest among fast growing corals.     

Patterns and rates of erosion in dead Porites across the Great Barrier Reef (Australia) after 2 years and 4 years of exposure

Rates and agents of erosion were investigated experimentally at six sites located along a cross shelf transect from the northern Queensland coast out into the Coral Sea. Rates of internal and external erosion of coral blocks, and accretion by coralline algae were measured after 2 years and 4 years of exposure. Blocks were cut from live colonies of Porites sp., which were collected from the outer barrier reef in north Queensland. They were then washed, dried, measured, weighed and attached to grids that were firmly attached to dead coral substrate at depths of 7–10 m. Significant differences in all three parameters were found within and among sites, and rates increased with increasing duration of exposure. Inshore sites were characterized by low rates of external erosion compared to offshore sites. Agents responsible for internal erosion differed among sites, with boring sponges being most abundant on the two inshore reefs, and molluscs most abundant at the offshore sites. Deposit-feeding polychaetes were more abundant at the two inshore sites, while filter and surface deposit feeders were more common at the offshore sites. Net erosion rates varied among sites (1.090±0.499 to 7.846±3.218 kg m²), and the relative importance of the components of erosion changed markedly along the cross-shelf transect.     

Behaviour of Dinosaurian Track-Makers in the Winton Formation (Cretaceous,Albian–Cenomanian) at Lark Quarry,Western Queensland,Australia: Running or Swimming?

A remarkable assemblage of dinosaur trackways in the Winton Formation (Albian–Cenomanian) at Lark Quarry, in western Queensland, Australia, has long been regarded as evidence of a stampede involving small theropods, whose tracks were classified in the ichnogenus Skartopus, and small ornithopods, whose tracks represented a second ichnogenus, Wintonopus. However, one recently-published study has claimed that existing interpretation of Lark Quarry is incorrect: it maintains that all the track-makers were ornithopods, that the ichnogenus Skartopus is a variant form of Wintonopus, and that most of the Lark Quarry track-makers were not running but more probably swimming downstream in a current of water. Those iconoclastic claims are investigated here and shown to be untenable. They derive from overgeneralized interpretation of the Lark Quarry track assemblage and invoke ad hoc auxiliary hypotheses which are either untestable or demonstrably incorrect. Closer inspection of the evidence underpinning those claims corroborates the existing interpretation of Lark Quarry as the site of a dinosaurian stampede and confirms the validity of the original distinction between theropod tracks (Skartopus) and ornithopod tracks (Wintonopus).     

Effects of recent increases in salinity and nutrient concentrations on the microbialite community of Lake Clifton (Western Australia): are the thrombolites at risk?

There has been a strong research focus on optical properties in temperate estuaries but very much less in tropical estuaries. These properties comprise light and beam attenuation dominated by suspended particulate matter, Chl a, and CDOM. Spatially and temporally distributed data on optical properties in a tropical wet and dry estuary are compared and discussed in relation to those of temperate estuaries. Sampling in the Nha Phu estuary, Vietnam, consisted of five stations on a transect from head to mouth that was sampled four times during dry conditions and three times during wet conditions between May 2006 and April 2008. Methods comprised CTD, optical measurements, and water sampling for suspended matter, Chl a, and CDOM. Results showed high light attenuation—K _d(PAR)—in wet conditions and low in dry. K _d(PAR) was highest at the estuary head and lower in the outer part. Spatial and temporal variations in K _d(PAR) were in general dominated by variations in suspended particulate matter concentrations in both wet and dry conditions. Chl a concentrations were low and showed no strong variations between wet and dry conditions. CDOM absorption coefficients were higher in wet conditions with high values at the head and lower in the central part of the estuary. The depth of the photic zone was reduced by up to 50% during wet conditions. A residence time in the estuary of 5–6 days was derived from the rate of change of K _d(PAR) after a period of heavy rain and discharge of freshwater into the estuary. This complied with a residence time of four and a half days derived from a basic physical relation. Optical properties were in general comparable to temperate estuaries in dry conditions although Chl a concentrations were lower in Nha Phu. A second distinctive point, as compared to temperate estuaries, was the episodic character with days of strong rainfall followed by longer periods of dry weather. All sampling, both wet and dry, was carried out in the dry season which implies a less definitive perception of wet and dry seasons.     

Spatial pattern of water bugs (Nepomorpha,Gerromorpha) at different scales in the Szigetköz (Hungary)

In 2003, 26 Heteroptera species (16 aquatic and 10 semiaquatic) were collected from 53 sampling sites in the Szigetköz region in Hungary. Hyocoris cimicoides and Gerris argentatus were the most frequent aquatic and semiaquatic species, respectively. Large differences both in the species number and species composition were observed among the different flood-prevention areas, arm systems and habitats. Strong negative correlation was found between the average number of aquatic species and current velocity, and a strong positive correlation between the average number of aquatic and semiaquatic species and macrophyte density. From a faunistic point of view, the marsh at Arak is the most interesting and valuable site.     

Microbial Fossils in the 2.63 Ga Jeerinah Formation,Western Australia—Evidence of Microbial Oxidation

A diamond drill core from the upper part of the Jeerinah Formation (～2.63 Ga), underlying the Hamersley Group, deposited at a time when the oxygen concentrations in the marine environment were extremely low, was examined for microbial fossils. The paper presents organo-mineral structures in the form of twisted stalks produced by bacteria being present in the laminated black carbonaceous shale sediments. These twisted stalks are organo-mineral structures produced by microaerophilic Fe(II)-oxidizing-type bacteria such as Gallionella and/or Mariprofundus that are active at very low-oxygen concentrations, thus providing evidence for oxygen being present in the marine environment at 2.63 Ga.     

Life-cycles of three populations of Potamogeton pectinatus L. at different degrees of wave exposure in the Askö area,Northern Baltic proper

Potamogeton pectinatus L. populations were studied at three stations over an annual cycle.The maximum standing crop of 17.5 g dry weight (wt.) m⁻² was recorded a the most sheltered station, decreasing slightly at the intermediate station to 15.8 g dry wt.m⁻², and being only 4.8 g dry wt.m⁻² at the most exposed station.Flowering and seed production occurred at all three stations. The maximum proportion of dry weight allocated to reproduction was higher at the more exposed stations (4%), while at the sheltered station only 1% was allocated to reproductive parts. The number of overwintering tubers produced per m² decreased from 115 per m² to 45 per m² with lowered exposure. Conversely, the number of flowers per inflorescence and flowers per m² was highest at the most sheltered station, decreasing from 9 to 6 and 945 to 672 per m², respectively, with increasing exposure. No definite trend could be found for seed production, which was highly variable and dependent on a successful period of fertilization during calm weather. At the sheltered locality more resources were allocated to vegetative shoots and rhizomes which were also able to overwinter.The resource allocation of Potamogeton pectinatus seems to be strongly influenced by environmental factors. This is discussed in relation to current reproductive strategy concepts.     

Long-term trends in the breeding populations of waterbirds (1951–1985) at a sewage treatment plant

Long-term (1951–1985) data on the breeding waterbird populations and habitat modifications at Cape Flats sewage treatment works (Strandfontein) and Rondevlei Bird Sanctuary (Rondevlei) were assessed to establish the main factors affecting the breeding species richness and nest abundance. Fifty-two 'water-associated' breeding species were recorded in the Zeekoe River catchment waterbodies, 46 (88.5%) at Strandfontein, 38 (73.1%) at Rondevlei Bird Sanctuary (Rondevlei), 33 (63.5%) at Zeekoevlei and ten (19.2%) at Princess Vlei. Thirteen (25.5%) of the species were unique to Strandfontein and five (9.8%) to Rondevlei. Sorenson's similarity indices indicated high similarity (C_s = 0.81) in species richness and low similarity in nest abundance pattern (C_N = 0.10) for the paired sites Strandfontein-Rondevlei. The lowest breeding species richness (11 species) was in winter (June) and the peak (42 species) was in spring (October). Twenty-four species joined the breeding population of Strandfontein during 1959–1976 (during which time pond water surface area increased 2372%). The mean breeding species richness increased significantly (χ ² ₂ = 14.42, P <0.001) at Strandfontein during three distinctive periods: 1951–1958 (pre-construction), 1959–1976 (construction) and 1977–1985 (stabilization). At Rondevlei there were no significant differences in breeding species richness during the same periods. However, there were significant differences in the nest abundance pattern between these grouped years, both at Strandfontein (χ ² ₂ = 1472.2, P <0.001) and at Rondevlei (χ ² ₂ = 60.28, P <0.001). It is suggested that the same pool of species use the heterogeneous habitats at all the sites in the catchment according to their availability. The remarkable increase in species richness and nest abundance at Strandfontein after the late 1970s is attributed to higher habitat structural complexity, broad habitat types, stabilization and maturation of pond water and the subsequent increase in food diversity and availability. The decrease in Rondevlei nesting populations after the 1960s is probably related to fluctuations in water levels, cover of mudbanks with vegetation and high density of alien fish. A multipurpose management concept for conservation is proposed for the Zeekoe River catchment area. Strandfontein provides the greatest diversity of aquatic habitats not available elsewhere in the catchment (habitats for rare breeders such as Avocet, Black-winged Stilt, Red-billed Teal and some plovers) Rondevlei has a complementary habitat spectrum (suitable for Great Crested Grebe, Podiceps cristatus, Little Bittern, Ixobrychus minutus, and reedbed species). Zeekoevlei provides a large area of reedbed habitat for colonial breeding species (African Spoonbill and herons) and Princess Vlei is suggested for attracting Laridae.     

Ecological Constraints on the Foraging Effort of Western Gorillas (Gorilla gorilla gorilla) at Bai Hoköu, Central African Republic

Recent studies demonstrate that western lowland gorillas incorporate much more fruit into their diet than Virunga mountain gorillas do. Very little is known, however, about how the frugivorous behavior of western gorillas influences their daily ranging behavior, which may ultimately affect social factors such as group size and structure. I examined the influence of diet and the spatiotemporal availability of plant foods on the foraging effort of nonhabituated western lowland gorilla groups during 17 months at Bai Hoköu in the Dzanga-Ndoki National Park, Central African Republic. I determined diet from indirect methods and gorilla plant food availability and spatial distribution from phenology and line transects. Daily path length gives an estimate of foraging effort and was the distance paced, following fresh gorilla trails, from morning to evening nest sites. The availability and distribution of fruit and its consumption by gorillas varied seasonally. When concentrating on fruits, gorillas traveled significantly farther (mean = 3.1 km/day) than when their diet consisted mostly of nonfruit vegetation, such as leaves and woody pith, stems, and bark (mean = 2.1 km/day). The amount of herbaceous vegetation in the diet did not vary seasonally and did not influence daily path length. The best environmental predictor of foraging effort was fruit density, or a measure combining both density and spatial pattern: coefficient of dispersion. In addition, when fruit patches were small, path length tended to increase but not significantly. Compared with results of other studies, gorillas at Bai Hoköu travel farther (mean = 2.6 km/day) than gorillas in Gabon (mean = 1.7 km/day) and five times farther than mountain gorillas in the Virungas (mean = 0.5 km/day). Increased foraging effort of gorillas in this region, especially during the fruiting season, may have profound effects on group size and structure.     

Redescription of Rugopharynx australis (Mönnig, 1926) and the description of R. moennigi n. sp. (Nematoda: Strongyloidea) from kangaroos (Marsupialia: Macropodidae) in Australia

Systematic Parasitology - Rugopharynx australis (Mönnig, 1926) (Nematoda: Strongyloidea) is redescribed based on specimens from the type host, Osphranter rufus (Desmarest), together with...     

Microatoll microbialites of Lake Clifton,Western Australia: Morphological analogues ofCryptozoön proliferum Hall,the first formally-named stromatolite

Summary The Linnaean nameCryptozo?n proliferum Hall was proposed in 1883 for a previously undescribed life-form preserved in spectacular exposures of Cambrian limestones in New York State, USA. It is now recognised that these are exposures of stromatolitic microbialites, laminated organosedimentary structures formed from interaction between a benthic microbial community (BMC) and the environment. Microbialites are neither fossil organisms nor trace fossils. These complex structures are the products of dissipative, self-organising systems involving a BMC, the external environment and the accreting microbialite. Functionally analogous BMCs of different species compositions may build similar structures in similar environments in quite separate periods. The type exposures ofCryptozo?n proliferum show objects composed of complex, concentric rings, up to a metre in diameter, that have grown laterally without any restriction other than that provided by neighbouring structures. They are not the relicts of domes truncated by penecontemporaneous erosion or Pleistocene glaciation, but depositional forms in which upward growth was restricted. Analogous modern structures occur on a reef platform along the north east shore of hyposaline Lake Clifton, Western Australia. These are tabular thrombolitic microbialites that vary lakeward across the reef platform from low, compound structures to discrete, concentric structures up to 50 cm high. The Lake Clifton forms are, in turn, morphological analogues of microatolls found on coral reef platforms. Coral microatolls are coral colonies with flat, dead tops and living perimeters in which upward growth is constrained by the sea surface. In shallow water they form circular rims of laterally growing coral around a dead centre. In deeper water they form coral heads that develop flat tops on reaching sea level. It is concluded that both the tabular microbialites of Lake Clifton and the type exposures ofCryptozo?n proliferum are analogous to coral microatolls in both form and origin-structures that have been able to grow laterally, but in which upward growth is restricted by subaerial exposure. Similar microatoll microbialites have been described from other modern environments, including Great Salt Lake, Utah, USA and Stocking Island, Exuma Cays, Bahamas. Ancient examples may include some of the “tufa” deposits of the Basal Purbeck Formation in Dorset, UK, as well as the coalesced domal bioherms of the Upper Cambrian Arrinthrunga Formation of the Georgina Basin, Central Australia, and the “washbowl” structures described from the B?tsfjord Formation of the Varanger Peninsula, north Norway. Progress towards a reliable interpretation of ancient microbialites depends on an understanding of modern environments in which analogous structures are forming. This study of microatolls has demonstrated that other sessile life forms may create colonial ecomorphs that, used cautiously, can serve as analogues for understanding the factors controlling the growth and form of microbialites. The surprising lack of pre-Pleistocene examples of microatolls recorded to date has simply been due to their lack of recognition in the geological record. They occur in sequences from the Proterozoic onwards, and provide powerful environmental indicators of ancient reef platforms on which biological growth was adjusted to contemporary sea level.     

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     

Four new species of Rugopharynx Mönnig, 1927 (Nematoda: Strongyloidea) parasitic in the stomachs of macropodid marsupials from Australia

Systematic Parasitology - Four new species of Rugopharynx Mönnig, 1927 are described from macropodid marsupials in Australia, some identified initially using molecular methods. Rugopharynx...