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Richards, Stephen J. - One of the best experts on this subject based on the ideXlab platform.

Stephen Richards - One of the best experts on this subject based on the ideXlab platform.

  • revision of the Litoria watjulumensis anura pelodryadidae group from the australian monsoonal tropics including the resurrection of l spaldingi
    Zootaxa, 2021
    Co-Authors: Stephen C Donnellan, Luke C Price, Paul Doughty, Sarah R Catalano, Stephen Pederson, Kieren J Mitchell, Aidan Suhendran, Stephen Richards
    Abstract:

    We show that the Wotjulum frog, Litoria watjulumensis (Copland, 1957), comprises two deeply divergent mitochondrial DNA lineages that are also reciprocally monophyletic for a nuclear gene locus and have discrete distributions. The taxa are differentiated in multivariate analysis of shape but show no appreciable differences in colour and pattern. The two taxa differ substantially in the degree of female biased sexual size dimorphism, with the western taxon showing considerably more pronounced dimorphism. We subsequently resurrect Litoria (Hyla) spaldingi (Hosmer, 1964) for populations from east of the Daly River system in the Northern Territory through to western Queensland and restrict L. watjulumensis to populations from the Kimberley region of north-western Australia and the Victoria River system of the western Northern Territory. The complex advertisement call of L. spaldingi is described for the first time.

  • a new species of large green treefrog Litoria pelodryadidae from papua indonesia
    Zootaxa, 2021
    Co-Authors: Paul M Oliver, Rainer Gunther, Burhan Tjaturadi, Stephen Richards
    Abstract:

    We describe a new species of large green treefrog from southern Papua Province, Indonesia. Litoria lubisi sp. nov. is placed in the L. infrafrenata Group based on its size, colouration and configuration of hand webbing, but differs from other members of this group in aspects of body size and proportions, extent of hand webbing, colouration and male advertisement call. Litoria lubisi sp. nov. occurs in close proximity to two other species in the L. infrafrenata Group, emphasising an until-recently overlooked pattern that multiple species of large, arboreal Litoria have overlapping distributions across much of the lowlands of southern New Guinea.

  • two new species of treefrog pelodrydidae Litoria from southern new guinea elucidated by dna barcoding
    Zootaxa, 2019
    Co-Authors: Paul M Oliver, Stephen Richards, Stephen C Donnellan
    Abstract:

    New Guinea is home to the world’s most diverse insular frog biota, but only a small number of taxa have been included in genetically informed assessments of species diversity. Here we describe two new species of New Guinea treefrog in the genus Litoria that were first flagged during assessments of genetic diversity (DNA barcoding) and are currently only known from the holotypes. Litoria pterodactyla sp. nov. is a large green species in the Litoria graminea species complex from hill forests in Western Province, Papua New Guinea and is the third member of this group known from south of the Central Cordillera. Litoria vivissimia sp. nov. is a small, spike-nosed species from mid-montane forests on the Central Cordillera. It is morphologically very similar to Litoria pronimia , but occurs nearly 1000 m higher than any known locality for that species. More extensive genetically informed assessment of diversity in New Guinea frogs seems certain to reveal many more as-yet-unrecognised taxa in complexes of morphologically similar species.

  • systematics of new guinea treefrogs Litoria pelodryadidae with erectile rostral spikes an extended description of Litoria pronimia and a new species from the foja mountains
    Zootaxa, 2019
    Co-Authors: Paul M Oliver, Rainer Gunther, Mumpuni Mumpuni, Stephen Richards
    Abstract:

    A small number of treefrog species (Litoria) from Melanesia are unusual amongst Anura in having distinctive fleshy rostral spikes. Here, we first present an extended description for Litoria pronimia Menzies, a small species that is widespread along the southern edge of the Central Cordillera of New Guinea, and in which males have a long and erectile rostral spike. Second, we describe Litoria pinocchio sp. nov. a new, morphologically similar, yet geographically disjunct species from the Foja Mountains in northern Papua Province, Indonesia. The new species differs from Litoria pronimia in aspects of body shape, proportions and colouration. A review of variation in the size, structure and degree of sexual dimorphism of the rostral spike across different species of Litoria suggests varying function including mate selection and camouflage.

  • a new species of treefrog Litoria from cape york peninsula australia
    Zootaxa, 2016
    Co-Authors: Keith R Mcdonald, Stephen Richards, Jodi J L Rowley, Greta J Frankham
    Abstract:

    We describe a new species of treefrog from northern Australia. Litoria bella sp. nov. is morphologically and genetically most similar to frogs in the L. gracilenta and L. chloris groups but is distinguished from all members in these groups by a combination of a moderately large male body size (34.5–41.8 mm SVL), near-immaculate green dorsum, orange venter, bright orange digits and webbing, bluish purple lateral surfaces of the thighs, no pale canthal stripe, white bones, and a highly-pulsed, single-note, male advertisement call with a pulse rate of 56–64 pulses/s and dominant frequency of 2.6–2.8 kHz. Litoria bella sp. nov. has a patchy distribution across the Cape York Peninsula, inhabiting rainforest and monsoon vine thicket in close association with watercourses. The new species’ affinities lie with L. auae from southern New Guinea rather than with L. gracilenta from eastern Australia. Molecular data suggest that the L. gracilenta group should be expanded to include L. chloris and L. xanthomera , two moderately large green treefrogs from eastern Australia.

Kirsten M. Parris - One of the best experts on this subject based on the ideXlab platform.

  • Interspecific variation in the phenology of advertisement calling in a temperate Australian frog community
    Ecology and evolution, 2015
    Co-Authors: Geoffrey W. Heard, Stefano Canessa, Kirsten M. Parris
    Abstract:

    Spatial and temporal partitioning of resources underlies the coexistence of species with similar niches. In communities of frogs and toads, the phenology of advertisement calling provides insights into temporal partitioning of reproductive effort and its implications for community dynamics. This study assessed the phenology of advertisement calling in an anuran community from Melbourne, in southern Australia. We collated data from 1432 surveys of 253 sites and used logistic regression to quantify seasonality in the nightly probability of calling and the influence of meteorological variables on this probability for six species of frogs. We found limited overlap in the predicted seasonal peaks of calling among these species. Those shown to have overlapping calling peaks are unlikely to be in direct competition, due to differences in larval ecology (Crinia signifera and Litoria ewingii) or differences in calling behavior and acoustics (Limnodynastes dumerilii and Litoria raniformis). In contrast, closely related and ecologically similar species (Crinia signfera and Crinia parinsignifera;Litoria ewingii and Litoria verreauxii) appear to have staggered seasonal peaks of calling. In combination with interspecific variation in the meteorological correlates of calling, these results may be indicative of temporal partitioning of reproductive activity to facilitate coexistence, as has been reported for tropical and temperate anurans from other parts of the globe.

  • distribution habitat requirements and conservation of the cascade treefrog Litoria pearsoniana anura hylidae
    Biological Conservation, 2001
    Co-Authors: Kirsten M. Parris
    Abstract:

    Thirty-three species of Australian frogs have apparently declined in abundance since the late 1970s, some perhaps to extinction. The cascade treefrog Litoria pearsoniana, a stream-breeding frog from the forests of sub-tropical eastern Australia, was listed as an endangered species in Queensland following reports of population declines between 1978 and 1984. However, these reports were based on limited field data. I conducted a stratified survey across the geographic and environmental range of L. pearsoniana to determine its current distribution, abundance and habitat requirements. I detected L. pearsoniana in all major areas of mesic forest within its historical range, and at 29 of 65 sites surveyed. Statistical habitat modelling demonstrated that L. pearsoniana was most likely to occur at large streams with mesic midstorey vegetation, as indicated by the presence of palms. Abundance of the species, conditional on presence at a site, increased with increasing stream size. Litoria pearsoniana appears to have recovered from earlier population declines. However, suitability of habitat for the species in extensive areas of public forest may be threatened by cattle grazing, and the associated practices of tree clearing and frequent burning.

Tjaturadi Burhan - One of the best experts on this subject based on the ideXlab platform.

Kara M Soule - One of the best experts on this subject based on the ideXlab platform.

  • light regulated photosynthetic gene expression and phosphoribulokinase enzyme activity in the heterokont alga vaucheria litorea xanthophyceae and its symbiotic molluskan partner elysia chlorotica gastropoda 1
    Journal of Phycology, 2012
    Co-Authors: Kara M Soule, Mary E Rumpho
    Abstract:

    Photosynthesis is composed of tightly coupled reactions requiring finely tuned nucleocytosolic-plastid interaction. Herein, we examined the influence of light on select photosynthetic gene expression and enzyme activity in the plastid-containing mollusk (sea slug) Elysia chlorotica and its heterokont algal prey Vaucheria litorea C. Agardh. Transcript levels of nuclear photosynthetic genes (psbO and prk) were significantly lower in E. chlorotica compared with V. litorea, whereas plastid photosynthesis genes (psaA and rbcL) were more comparable, although still lower in the animal. None of the genes responded similarly to changes in light conditions over a 24 h period in the sea slug compared with the alga. Activity of the nuclear-encoded photosynthetic enzyme phosphoribulokinase (PRK) exhibited redox regulation in vitro in crude extracts of both organisms sequentially treated with oxidizing and reducing agents. However, PRK was differentially affected in vivo by redox and light versus dark treatment in V. litorea, but not in E. chlorotica. Overall, these results support the active transcription of algal nuclear and plastid genes in E. chlorotica, as well as sustained activity of a nuclear-encoded plastid enzyme, even after several months of starvation (absence of algal prey). The apparent absence of tight transcriptional regulation and redox control suggests that essential nuclear-encoded regulatory factors in V. litorea are probably not present in the sea slug. These findings are discussed relative to light regulation of photosynthetic gene expression in the green and red algal lineages and in the context of the sea slug/algal plastid kleptoplastic association.

  • molecular characterization of the calvin cycle enzyme phosphoribulokinase in the stramenopile alga vaucheria litorea and the plastid hosting mollusc elysia chlorotica
    Molecular Plant, 2009
    Co-Authors: Mary E Rumpho, Sirisha Pochareddy, Jared M Worful, Elizabeth J Summe, Debashish Hattacharya, Karen N. Pelletreau, Mary S Tyle, James R Manha, Jungho Lee, Kara M Soule
    Abstract:

    Phosphoribulokinase (PRK), a nuclear-encoded plastid-localized enzyme unique to the photosynthetic carbon reduction (Calvin) cycle, was cloned and characterized from the stramenopile alga Vaucheria litorea. This alga is the source of plastids for the mollusc (sea slug) Elysia chlorotica which enable the animal to survive for months solely by photoautotrophic CO2 fixation. The 1633-bp V. litorea prk gene was cloned and the coding region, found to be interrupted by four introns, encodes a 405-amino acid protein. This protein contains the typical bipartite target sequence expected of nuclear-encoded proteins that are directed to complex (i.e. four membrane-bound) algal plastids. De novo synthesis of PRK and enzyme activity were detected in E. chlorotica in spite of having been starved of V. litorea for several months. Unlike the algal enzyme, PRK in the sea slug did not exhibit redox regulation. Two copies of partial PRK-encoding genes were isolated from both sea slug and aposymbiotic sea slug egg DNA using PCR. Each copy contains the nucleotide region spanning exon 1 and part of exon 2 of V. litorea prk, including the bipartite targeting peptide. However, the larger prk fragment also includes intron 1. The exon and intron sequences of prk in E. chlorotica and V. litorea are nearly identical. These data suggest that PRK is differentially regulated in V. litorea and E. chlorotica and at least a portion of the V. litorea nuclear PRK gene is present in sea slugs that have been starved for several months.