Breedng season, larval development and diseprsal of Lingula anatina (Brachiopoda, Inarticulata) from Townsville, Australia

A discrete but protracted breeding season, extending from October to April, was defined for Lingula anatina from Townsville, Australia, using gonad indices, sizes of developing ova, occurrence of planktonic larvae and analysis of size frequency distribution of an adult population. Comparison of temperate and tropical records suggests that the duration of the breeding season is regulated by temperature. The minimum age at which larvae achieve competence to settle is approximately the same in temperate and tropical waters, but in both regions development and growth occur at a very variable rate. A number of morphological features which can be considered precursors to settlement are closely associated in their development, which may proceed in response to settlement cues provided by proximity to the substratum. The varying intensity of such cues in different environments may be responsible for delays before some larvae realize competence to settle, accounting for much of the variability in the development process. Accordingly, differences between collections of Indo-West Pacific Lingula larvae can be rationalized; all records are now referred to L. anatina . Extension of pelagic larval life in lingulid larvae appears to involve a strategy different from that of most other marine invertebrates.     

Modern Data on the Innervation of the Lophophore in Lingula anatina (Brachiopoda) Support the Monophyly of the Lophophorates

Evolutionary relationships among members of the Lophophorata remain unclear. Traditionally, the Lophophorata included three phyla: Brachiopoda, Bryozoa or Ectoprocta, and Phoronida. All species in these phyla have a lophophore, which is regarded as a homologous structure of the lophophorates. Because the organization of the nervous system has been traditionally used to establish relationships among groups of animals, information on the organization of the nervous system in the lophophore of phoronids, brachiopods, and bryozoans may help clarify relationships among the lophophorates. In the current study, the innervation of the lophophore of the inarticulate brachiopod Lingula anatina is investigated by modern methods. The lophophore of L. anatina contains three brachial nerves: the main, accessory, and lower brachial nerves. The main brachial nerve is located at the base of the dorsal side of the brachial fold and gives rise to the cross neurite bundles, which pass through the connective tissue and connect the main and accessory brachial nerves. Nerves emanating from the accessory brachial nerve account for most of the tentacle innervation and comprise the frontal, latero-frontal, and latero-abfrontal neurite bundles. The lower brachial nerve gives rise to the abfrontal neurite bundles of the outer tentacles. Comparative analysis revealed the presence of many similar features in the organization of the lophophore nervous system in phoronids, brachiopods, and bryozoans. The main brachial nerve of L. anatina is similar to the dorsal ganglion of phoronids and the cerebral ganglion of bryozoans. The accessory brachial nerve of L. anatina is similar to the minor nerve ring of phoronids and the circumoral nerve ring of bryozoans. All lophophorates have intertentacular neurite bundles, which innervate adjacent tentacles. The presence of similar nerve elements in the lophophore of phoronids, brachiopods, and bryozoans supports the homology of the lophophore and the monophyly of the lophophorates.     

Genetic structure of three populations of the 'living fossil' brachiopod Lingula from Queensland, Australia

An electrophoretic survey of enzyme variation demonstrates that the genomes of three populations of the inarticulate brachiopod Lingula contain a higher level of variability than the average for marine, tropical invertebrates, and for other brachiopods. Genetic distances between populations from localities up to 1200 km apart were very small, indicating that the populations belong to a single species, L. anatina Lamarck. These data suggest that larval dispersal is capable of maintaining a homogeneous gene pool over this range. It is predicted that the dispersal mechanism is sufficiently efficacious to ensure gene-flow throughout most of the Indo-West Pacific distribution of Lingula. Further investigations of genetic distance should support the hypothesis, based on studies of adult and larval morphology, that many presently recognized species should be reassigned to L. anatina.     

Blood cells and coelomocytes of the inarticulate brachiopod Lingula anatina

Three cell types are described from the coelomic cavity of the pedicle of the brachiopod Lingula anatina . Erythrocytes are abundant in the blood vessels of the mantle and also occur, in reduced numbers, in the pedicle. Phagocytic amoebocytes, characterized by a variable number of electrondense, homogeneous granules are common in the coelomic fluid of the pedicle. The enigmatic spindle bodies described by earlier authors constitute the most common cell type encountered in the pedicle coelom of aquarium-maintained specimens. The origin of spindle bodies from muscle cells is suggested.     

Population structure and dispersal of the saltmarsh mosquito Aedes vigilax in Queensland, Australia

Population genetics of the mosquito Aedes vigilax (Skuse) (Diptera: Culicidae), a major vector of arboviruses (e.g. Barmah Forest, Ross River), were investigated to obtain an indirect estimate of mosquito dispersal characteristics in typical habitats of Aedes vigilax in south-east Queensland: on the off-shore islands of Moreton Bay and on the mainland where disjunct breeding populations of Ae. vigilax are distributed along intertidal marsh. Six allozyme loci were assessed for genetic differentiation between samples from 11 localities. Significant larval variation between some breeding sites was attributed to site-specific selection. Nonsignificant genetic differentiation was found among collections of adult mosquitoes caught in light traps throughout the study area (exceeding 60x27 km), indicating widespread dispersal. As distances of < or = 9 km over water did not appear to act as effective barriers to Ae. vigilax dispersal, localized control activities applied to Ae. vigilax breeding sites are unlikely to be effective against the vagile adult population. Therefore, the contiguous shires programme of broad acre control is endorsed to prevent the spread of arboviruses carried by Ae. vigilax     

Population structure of Macrobrachium australiense (Decapoda: Palaemonidae) in Western Queensland, Australia: the role of contemporary and historical processes

Rivers of Western Queensland, Australia, represent a discontinuous and variable aquatic habitat for the freshwater fauna of the region. Rivers periodically fluctuate between being highly fragmented, with numerous disconnected waterholes and ephemeral channels, and being highly connected by a dominant system of anastomosing channels. We used mitochondrial sequences to investigate the genetic structure and inferred patterns of dispersal associated with this flow regime for the freshwater prawn, Macrobrachium australiense (Decapoda: Palaemonidae), sampling 28 localities throughout eight catchments. Based on a 505 base pair fragment of mitochondrial cytochrome c oxidase subunit I, we identified 98 haplotypes in a sample of 402 individuals. The haplotypes clustered into two main clades corresponding geographically to the major drainages: the Lake Eyre and Murray-Darling basins. Populations of M. australiense inhabiting the two basins appear to have diverged around 800,000 years ago (estimated sequence divergence of 1.6%). Analysis of population differentiation indicated contemporary high levels of genetic subdivision and restricted gene flow among populations within and among catchments. Phylogenetic analysis detected a series of historical range expansions in the region and we suggest that climate fluctuations during the Pleistocene have resulted in extensive floods that have promoted historical movements of aquatic organisms across catchment boundaries.     

Genetic structure and dispersal of Macrobrachium australiense (Decapoda: Palaemonidae) in western Queensland, Australia

SUMMARY 1. The freshwater prawn, Macrobrachium australiense (Decapoda: Palaemonidae), is an abundant species throughout the rivers of western Queensland, and it is thought to have effective dispersal capabilities. Given the very low topographical relief of the western Queensland landscape and the vast nature of episodic flooding, it was predicted that widespread dispersal in this species would occur within, and possibly between the four major catchments of the region: the Darling, Bulloo, Cooper and Diamantina. We analysed eight polymorphic allozyme systems and a fragment of the cytochrome c oxidase subunit 1 (COI) mitochondrial DNA (mtDNA) gene to determine the extent of recent and historical patterns of dispersal at nested spatial scales, within and between catchments.
2. Large and significant levels of allozyme and mtDNA differentiation were revealed among all catchments, indicating that dispersal of M. australiense does not occur across catchment boundaries, although this species is reportedly capable of overland movement. In contrast, no significant patterns of genetic differentiation were resolved between major subcatchments of the Darling and Cooper, or between sites within these subcatchments, indicating that populations of M. australiense are panmictic within catchments.
3. The MtDNA data resolved two divergent and reciprocally monophyletic clades, with the first representing the Darling catchment, and the second corresponding to the Bulloo, Cooper and Diamantina catchments. We postulate that extreme variation in historical climatic patterns and palaeohydrologic conditions played an important role in shaping the population structure of M. australiense throughout western Queensland during the Quaternary.     

Ultrastructure and immunocytochemistry of the nervous system of the larvae ofLingula anatina andGlottidia sp. (Brachiopoda)

Summary Planktotrophic brachiopod larvae ofGlottidia sp. have been investigated for the occurrence of glyoxylic acid induced fluorescence in catecholamines (CA), and serotonin-like (5-HT) and neuropeptide FMRFamidelike (FMRFamide) immunoreactivity (ir). The location of CA, 5-HT-ir and FMRFamide-ir cells and processes were compared with the location of neurons and nerve processes found by transmission electron microscopy. The apical ganglion contains 5-HT-ir and FMRFamideir cells and processes and CA processes. From the dorsal part of the apical ganglion extend dorsal 5-HT-ir and FMRFamide-ir processes; from the nine pairs of tentacles stage (9. pt) they project to the ventral ganglion. These dorsal lophophore processes follow themusculus lophophoralis and them. brachialis. The 5-HT-ir and some of the FMRFamide-ir processes project along the muscles to the tentacles. From the ventral part of the apical ganglion extend CA, 5-HT-ir and FMRFamide-ir processes which follow the ciliary band of the lophophore and project to the tentacles. An intense band of CA processes was also observed in the lophophore, but the dorsal/ventral location could not be ascertained. The ventral ganglion contains 5-HT-ir and FMRFamide-ir cells which project either caudally on the metasome or rostrally as part of the dorsal lophophore processes. The neuropil of the ventral ganglion contains CA, 5-HT-ir and FMRFamide-ir processes. The nervous system of the planktotrophic brachiopod larvae seems to consist of a ventral lophophore system innervating the ciliary bands and a dorsal lophophore system including the ventral ganglion innervating the body musculature. The latter system develops later in ontogeny and is regarded as a specialization due to the presence of shells and associated musculature. The former system is regarded as homologous with the nervous system of actinotroch larvae (Phoronida) and planktotrophic larvae of the echinoderms.     

Sphaeromatid lsopods (Crustacea) from Brackish Waters in Queensland, Australia

Exosphaeroides fluvialis gen. et sp.n. is recorded from a number of estuaries along the mainland coast of Queensland and Cymodetta gracilipes sp.n. is recorded from sediment amongst mangroves and in a 'dry' location on Lizard Island, in the Great Barrier Reef. The brackish water species Cymodetta gambosa Bowman & Kühne is redescribed and the genus is transferred from the hemibranchiate to the platybranchiate group of Sphaeromatidae. Another brackish water sphaeromatid, Exosphaeroma alatum Baker, is also redescribed and is removed from the hemibranchiate Sphaeromatidae to form the type-species of a eubranchiate genus, Ptyosphaera gen.n. Details are given of the occurrence of sphaeromatid isopods in brackish water in Australia. Sphaeroma triste Heller, a wood-boring sphaeromatid, is reported from Australia for the first time. A discussion is given concerning the colonization of brackish water and freshwater by sphaeromatids throughout the world.     

Reproduction and growth of Craterocephalus marjoriae and C. stercusmuscarum (Pisces: Atherinidae) in south-eastern Queensland, Australia

SUMMARY. 1. The reproductive cycle and growth of Craterocephalus marjoriae and Craterocephalus stercusmuscarum (Atherinidae) were studied in Brisbane, south-eastern Queensland, over a 17-month period (1981–82).
2. Both species had a 5-month breeding season in spring and summer, with a breeding peak in spring (September-October). Multiple spawning occurred but life time fecundity was not determined.
3. Gonosomatic index values and mean fecundity per female were higher in Craterocephalus marjoriae than in C. stercusmuscarum. Fecundity increased with body length in both species according to the relationship, F=aL^b. Growth rates were similar and growth was adequately described by the von Bertalanffy equation. Both species grew rapidly during the first year and reached maturity the following season. Reproductive strategies are considered in relation to seasonal flooding in the streams inhabited.     

The ecology of pre-imaginal simuliidae (Diptera) in South-East Queensland,Australia

A study of the pre-imaginal simuliid fauna of South-East Queensland was conducted to elucidate some of the aspects of their ecology. A total of 17 species of three genera (Cnephia, Austrosimulium and Simulium) bred in the area. The highest diversity of species was found to occur in mountainous areas near the coast which had the following conditions: high rainfall, steep relief, cool temperatures, on the edge of forests with streams of the order 1–3 (using a 1 : 250,000 map).More detailed studies of A. bancrofti, S. nicholsoni and S. ornatipes were made to investigate microdistribution, colonization, drift, pupation timing and population changes. Current velocity was the most important factor determining the distribution of A. bancrofti, while the distribution of S. nicholsoni was influenced by a preference for vegetation substrate and current velocity. Late instar larvae of A. bancrofti and S. ornatipes occurred in faster currents than early instar larvae. Pupae of these two species primarily occurred on the downstream side of submerged substrates. Colonization of a particular stream was dependent on the oviposition preference of gravid females while drift, looping, or descent on silk threads was used for larval dispersal from the oviposition site. Early instars of A. bancrofti drifted from quiet reaches of mature rivers to rapids, while S. ornatipes larvae appeared to be more sessile with limited dispersal from site of egg masses. Drift occurred throughout 24 hours with little change in total numbers. Early instars of A. bancrofti however showed a definite diurnal tendency while the proportion of late instars increased at night. Pupation of S. ornatipes was diurnal under undisturbed conditions. The larvae of A. bancrofti and S. nicholsoni both developed in the Brisbane River system, however the populations of A. bancrofti peaked in late winter, a dry season with stable water conditions while S. nicholsoni larvae were most abundant from late summer, at the end of the rains to the early winter. The larvae of S. ornatipes, which occur in small streams down to temporary trickles, were most numerous during the warm rainy period.Department of Parasitology, University of Queensland     

Stratigraphic and geographic distribution of acrotretids (Brachiopoda,Lingulata) in the Middle and Late Cambrian

The analysis of the taxonomic composition and distribution of acrotretids (Brachiopoda) in the Middle Cambrian and early Late Cambrian shows that, in the later half of the Cambrian, the order Acrotretida was the most abundant brachiopod order and many of its representatives were cosmopolites. The structure, mode of life, and biological features of acrotretids, along with the arrangement of continents with epicontinental seasmostly in the low latitudes, promoted the wide dispersal of this group on the Earth in the Cambrian.     

Periodontal disease in feral pigs (Sus scrofa) from Queensland, Australia

Periodontal lesions were present in 26 of 107 feral pigs (Sus scrofa) that were shot in southern Queensland. The severity of the lesions varied from gingivitis to extensive destruction of the alveolus and its contents. Examination of slaughtered domestic pigs revealed a similar prevalence of lesions (12 of 52). Only cheek teeth were affected, and molars were affected more frequently than premolars. In both feral and domestic pigs, prevalence of periodontal disease affecting bone increased with age. Although periodontal disease is recognized as a common and often serious problem in many mammalian species, both domestic and wild, it has rarely been recorded in the pig. It is considered that the most severe lesions would have interfered with mastication but that the contribution of the disease to mortality of feral pigs in Australia is probably not great.     

New Mid-Cretaceous (Latest Albian) Dinosaurs from Winton,Queensland, Australia

Background

Australia''s dinosaurian fossil record is exceptionally poor compared to that of other similar-sized continents. Most taxa are known from fragmentary isolated remains with uncertain taxonomic and phylogenetic placement. A better understanding of the Australian dinosaurian record is crucial to understanding the global palaeobiogeography of dinosaurian groups, including groups previously considered to have had Gondwanan origins, such as the titanosaurs and carcharodontosaurids.

Methodology/Principal Findings

We describe three new dinosaurs from the late Early Cretaceous (latest Albian) Winton Formation of eastern Australia, including; Wintonotitan wattsi gen. et sp. nov., a basal titanosauriform; Diamantinasaurus matildae gen. et sp. nov., a derived lithostrotian titanosaur; and Australovenator wintonensis gen. et sp. nov., an allosauroid. We compare an isolated astragalus from the Early Cretaceous of southern Australia; formerly identified as Allosaurus sp., and conclude that it most-likely represents Australovenator sp.

Conclusion/Significance

The occurrence of Australovenator from the Aptian to latest Albian confirms the presence in Australia of allosauroids basal to the Carcharodontosauridae. These new taxa, along with the fragmentary remains of other taxa, indicate a diverse Early Cretaceous sauropod and theropod fauna in Australia, including plesiomorphic forms (e.g. Wintonotitan and Australovenator) and more derived forms (e.g. Diamantinasaurus).     

The spatial and vertical distribution of living (stained) benthic foraminifera from a tropical,intertidal environment,north Queensland,Australia

We investigated the distribution of living (stained) benthic foraminifera across a tropical, intertidal shoreline adjacent to Cocoa Creek, Queensland, Australia for the purpose of better understanding the nature of test production and ultimately fossil assemblage development within such environments. Short cores (up to 1 m) were collected during the wet and dry season, along an elevational gradient comprising non-vegetated intertidal mudflat and higher-intertidal mangrove forest environments. The distribution of stained specimens can be broadly delineated into assemblages characterising ‘upper mangrove’ (2.64–2.91 m above Lowest Astronomical Tide (LAT)) and ‘low mangrove-mudflat’ (1.62–2.18 m above LAT) environments. Agglutinated species were generally limited to upper mangrove stations. Calcareous species occurred within all of the intertidal environments examined but differ in their composition between upper and lower intertidal settings. Upper mangrove faunas were characterised by the agglutinated species Arenoparrella mexicana, Haplophragmoides wilberti, Miliammina fusca, Miliammina obliqua and Trochammina inflata and the calcareous species Helenina anderseni. Live (stained) assemblages at lower intertidal elevations were dominated by the calcareous species Ammonia aoteana, as well as Rosalina spp., Elphidium oceanicum, Triloculina oblonga, Ammonia pustulosa and Shackoinella globosa.     

SomeCortinarius spp. (Agaricales) of the Cooloola Sand-Mass,Queensland, Australia

Four distinct species ofCortinarius referable to subg.Dermocybe are described from the Cooloola Sand-Mass, Queensland; two are formally recognized asC. alkalivirens, spec. nova andC. chromobasis, spec. nova, whilst notes are provided for the other two. Chemical methods and cladistic studies are applied and indicate a new section of the subgenus is required.Australodermocybe sect. nova is proposed.     

A new species of Gillbeea (Cunoniaceae) from north-eastern Queensland, Australia

Gillbeea whypallana sp. nov. is described from the Wet Tropics of North Queensland. This species differs from G. adenopetala in the larger serrate asymmetrical stipules, hirsute leaves and fruits and the number of lateral veindleaflet. Gillbeea adenopetala and G. whypallana both differ from G. papuana in having hairs on the lateral margins of the petals, and in having more than two ovules per carpel. The comparative morphology of the three Gillbeea species is described and illustrated, and the phylogenetic placement of the genus within the Cunoniaceae is discussed briefly.