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Daniel J.d. Natusch - One of the best experts on this subject based on the ideXlab platform.

  • Species delimitation and systematics of the green pythons (Morelia viridis complex) of melanesia and Australia.
    Molecular phylogenetics and evolution, 2019
    Co-Authors: Daniel J.d. Natusch, Damien Esquerré, Jessica A. Lyons, Amir Hamidy, Alan R. Lemmon, Emily Moriarty Lemmon, Awal Riyanto, J. Scott Keogh, Stephen C. Donnellan
    Abstract:

    Abstract Molecular data sets and the increasing use of integrative systematics is revealing cryptic diversity in a range of taxa – particularly in remote and poorly sampled landscapes like the island of New Guinea. Green pythons (Morelia viridis complex) are one of the most conspicuous elements of this island’s fauna, with large numbers taken from the wild to supply international demand for exotic pets. We test hypotheses about species boundaries in green pythons from across New Guinea and Australia with mitochondrial genomes, 389 nuclear exons, and comprehensive assessment of morphological variation. Strong genetic structuring of green python populations and species delimitation methods confirm the presence of two species, broadly occurring north and south of New Guinea’s central mountains. Our data also support three subspecies within the northern species. Subtle but consistent morphological divergence among the putative taxa is concordant with patterns of molecular divergence. Our extensive sampling identifies several zones of hitherto unknown biogeographical significance on the island of New Guinea. We revise the taxonomy of the group, discuss the relevance of our findings in the context of Papuan biogeography and the implications of our systematic changes for the conservation management of these taxa.

  • Geographic and Sexual Variations in Body Size, Morphology, and Diet among Five Populations of Green Pythons (Morelia viridis)
    Journal of Herpetology, 2014
    Co-Authors: Daniel J.d. Natusch, Jessica A. Lyons
    Abstract:

    Abstract Body sizes and morphological traits of animals are often strongly influenced by their diet. Several studies have shown this to be true for snakes and have linked intraspecific differences in these attributes to geographic and sexual variations in prey sizes and diet. To help clarify anecdotal reports of morphological variation among populations of Green Pythons (Morelia viridis), we assessed geographic and sexual variations in the body size, morphology, and diet of 908 individuals from five sites in Australia and New Guinea. Body sizes and morphology differed among populations and, although some variation could be explained by sampling biases, we found no significant geographic dietary variation to help explain these differences. Juvenile Green Pythons preyed exclusively on small lizards and adults preyed on mammals, while birds comprised only 2.5% of all dietary records. Within all populations females grow to larger body sizes, although we observed little sexual dimorphism in other traits. Males...

  • effects of consumer preferences for rarity on the harvest of wild populations within a species
    Ecological Economics, 2013
    Co-Authors: Jessica A. Lyons, Daniel J.d. Natusch
    Abstract:

    Economic theory predicts that exploitation of a species alone is unlikely to result in extinction because of escalating costs involved in finding increasingly rare individuals of a declining species. However, a recently proposed hypothesis, the Anthropogenic Allee Effect (AAE), proposes that if people place disproportionate value on rare species, this may result in a cycle whereby increased exploitation reduces the population size, thus increasing its value and ultimately leading to its extinction in the wild. We tested this hypothesis using data collected on wild harvests, preferences of pet keepers and sale prices of different populations of green pythons (Morelia viridis) and hypothesized that the AAE could occur among population within species, not just between them. The rarity of populations of green pythons was strongly positively correlated with price and negatively correlated with harvest levels. The two populations that were deemed most desirable by pet collectors exhibited abnormal coloration and were found to be suffering from the effects of over-exploitation for the pet trade. Adequate regulation and enforcement are needed to reduce the effects of demand on illegal harvesting and conservationists and government bodies should be aware of the effects of disclosing the rarity of a species and its populations.

  • Relationships between ontogenetic changes in prey selection, head shape, sexual maturity, and colour in an Australasian python (Morelia viridis)
    Biological Journal of the Linnean Society, 2012
    Co-Authors: Daniel J.d. Natusch, Jessica A. Lyons
    Abstract:

    Prey selection in many species is known to change ontogenetically, suggesting that associated changes in trophic structure may also be important. Several studies have examined relationships between prey selection and the size of trophic structures; however, few have explored these changes over ontogeny or the effects that they may have on a species broader ecology. The present study addressed this issue by examining relationships between changes in head size and prey selection in juveniles and adults from three populations of the python Morelia viridis and related them to changes in sexual maturity and ontogenetic changes in colour (OCC). Our scaling data for head size showed that juveniles and adults scaled mostly with negative allometry, and allometric slopes were significantly different before and after OCC. The change in head shape allometry was strongly associated with changes in prey selection from ectothermic to endothermic prey and with OCC in two of the three populations studied. OCC in the other population varied widely and may be the result of isolation on an oceanic island. Negatively allometric head growth is common in vertebrates and may serve a functional role in M. viridis by reducing the maximum ingestible prey size in adults, thus aiding arboreality. Our data do not allow us to test which of these changes have causal or resultant effects on one another; however, we suggest they may be part of an overall evolutionary defence‐foraging strategy that circumvents costs imposed by restricting foraging opportunities to certain habitats. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, , ••‐••.

  • Consumer driven conservation of green pythons is possible if the price is right: A reply to Pernetta (2012)
    Biological Conservation, 2012
    Co-Authors: Jessica A. Lyons, Daniel J.d. Natusch
    Abstract:

    Preventing unsustainable and illegal trade of wildlife is vital for protecting biodiversity, yet finding ways to monitor and minimise such trade cost-effectively remains a significant challenge. Recently, Pernetta (2012) criticised our suggestion to use eggshells as a means of regulating the laundering of illegally wild-caught green pythons (Morelia viridis) through breeding farms in Indonesia viz. if a snake was bred at a farm it must have an accompanying eggshell (Lyons and Natusch 2011). Pernetta (2012) suggested that such a method may create demand for gravid females from wild populations and argued that it should not be used as the sole tool for preventing laundering. Instead, Pernetta (2012) suggested that a chain of custody should be set up whereby microsatellite genotyping and parentage assignment techniques would provide a fool-proof method of unequivocally identifying wild-caught snakes, the funding for which could be procured via a conservation tax levied from end consumers. We agree with Pernetta (2012) that the eggshell method should not be used as the sole tool, but one part of a multi tiered, integrated and holistic approach to combating illegal harvest of green pythons. Despite being omitted from Pernetta’s (2012) review, our paper also suggested several other means of minimising illegal collection; educating the consumer market, husbandry training, determining the economic viability of green python farming and allowing limited legal collection of wild individuals. The beauty of the eggshell method, however, lies in its simplicity; it is cost effective and can be implemented immediately. We argue, based on our fieldwork, that unless demand for green pythons (and therefore market price) significantly increases, the time involved in searching for gravid females makes it impractical. Indeed, of the 1733 green pythons collected by traders and thoroughly examined by us, 0.4% (7) were gravid females. While it may be naive to assume that intensive searching for selective harvests will not occur in the future, currently every snake encountered by collectors is taken for the pet trade – gravid or not. Although microsatellite genotyping and parentage assignment techniques may be a valid means of regulating illegal trade, they will take a considerable time to introduce and have significant associated cost. These techniques are currently not done for any species in Indonesia, not even those of high commercial value or those that are globally threatened, and it is a stretch to expect Indonesian authorities to introduce this system for green pythons. Further, many of the farms regularly exporting green pythons from Indonesia do not have parent stock from which to allow parentage assignment. As an initial step in monitoring and enforcement, which can be implemented immediately at minimal cost, proof of breeding (in the form of eggshells) is sufficient to identify which farms are providing fallacious breeding records. Simply the added request of enclosing eggshells (and not even measuring them) would curtail much of this trade. We suggest, therefore, that while the application of genetic forensic techniques may be more reliable than the eggshell method, the significant cost involved currently makes them impractical for regulating farming operations in Indonesia. Despite consumers preferring captive-bred green pythons over wild-caught ones (Auylia, 2003) Indonesian ‘‘farm-bred’’ snakes are attractive due to their lower market price (USD 225 compared to USD 500, respectively). Indonesian exporters currently sell snakes at these prices because of the reduced cost involved in collecting and exporting wild-caught individuals. By comparison, housing, feeding and breeding green pythons at farms may not be economically feasible if prices are not increased. Raising the price of farm-bred individuals, however, and imposing a conservation tax on their exportation will inevitably reduce demand for some snakes from Indonesia. For breeding farms to be successful, and in the presence of proper regulatory measures for preventing illegal harvests, they should provide a cheaper, more acceptable product to the consumer than wild-caught animals. Thus, for sustainable farming of green pythons, changing consumer attitudes from being price-based to conservation focussed can be achieved – but only if the price is right.

Jessica A. Lyons - One of the best experts on this subject based on the ideXlab platform.

  • Species delimitation and systematics of the green pythons (Morelia viridis complex) of melanesia and Australia.
    Molecular phylogenetics and evolution, 2019
    Co-Authors: Daniel J.d. Natusch, Damien Esquerré, Jessica A. Lyons, Amir Hamidy, Alan R. Lemmon, Emily Moriarty Lemmon, Awal Riyanto, J. Scott Keogh, Stephen C. Donnellan
    Abstract:

    Abstract Molecular data sets and the increasing use of integrative systematics is revealing cryptic diversity in a range of taxa – particularly in remote and poorly sampled landscapes like the island of New Guinea. Green pythons (Morelia viridis complex) are one of the most conspicuous elements of this island’s fauna, with large numbers taken from the wild to supply international demand for exotic pets. We test hypotheses about species boundaries in green pythons from across New Guinea and Australia with mitochondrial genomes, 389 nuclear exons, and comprehensive assessment of morphological variation. Strong genetic structuring of green python populations and species delimitation methods confirm the presence of two species, broadly occurring north and south of New Guinea’s central mountains. Our data also support three subspecies within the northern species. Subtle but consistent morphological divergence among the putative taxa is concordant with patterns of molecular divergence. Our extensive sampling identifies several zones of hitherto unknown biogeographical significance on the island of New Guinea. We revise the taxonomy of the group, discuss the relevance of our findings in the context of Papuan biogeography and the implications of our systematic changes for the conservation management of these taxa.

  • Geographic and Sexual Variations in Body Size, Morphology, and Diet among Five Populations of Green Pythons (Morelia viridis)
    Journal of Herpetology, 2014
    Co-Authors: Daniel J.d. Natusch, Jessica A. Lyons
    Abstract:

    Abstract Body sizes and morphological traits of animals are often strongly influenced by their diet. Several studies have shown this to be true for snakes and have linked intraspecific differences in these attributes to geographic and sexual variations in prey sizes and diet. To help clarify anecdotal reports of morphological variation among populations of Green Pythons (Morelia viridis), we assessed geographic and sexual variations in the body size, morphology, and diet of 908 individuals from five sites in Australia and New Guinea. Body sizes and morphology differed among populations and, although some variation could be explained by sampling biases, we found no significant geographic dietary variation to help explain these differences. Juvenile Green Pythons preyed exclusively on small lizards and adults preyed on mammals, while birds comprised only 2.5% of all dietary records. Within all populations females grow to larger body sizes, although we observed little sexual dimorphism in other traits. Males...

  • effects of consumer preferences for rarity on the harvest of wild populations within a species
    Ecological Economics, 2013
    Co-Authors: Jessica A. Lyons, Daniel J.d. Natusch
    Abstract:

    Economic theory predicts that exploitation of a species alone is unlikely to result in extinction because of escalating costs involved in finding increasingly rare individuals of a declining species. However, a recently proposed hypothesis, the Anthropogenic Allee Effect (AAE), proposes that if people place disproportionate value on rare species, this may result in a cycle whereby increased exploitation reduces the population size, thus increasing its value and ultimately leading to its extinction in the wild. We tested this hypothesis using data collected on wild harvests, preferences of pet keepers and sale prices of different populations of green pythons (Morelia viridis) and hypothesized that the AAE could occur among population within species, not just between them. The rarity of populations of green pythons was strongly positively correlated with price and negatively correlated with harvest levels. The two populations that were deemed most desirable by pet collectors exhibited abnormal coloration and were found to be suffering from the effects of over-exploitation for the pet trade. Adequate regulation and enforcement are needed to reduce the effects of demand on illegal harvesting and conservationists and government bodies should be aware of the effects of disclosing the rarity of a species and its populations.

  • Relationships between ontogenetic changes in prey selection, head shape, sexual maturity, and colour in an Australasian python (Morelia viridis)
    Biological Journal of the Linnean Society, 2012
    Co-Authors: Daniel J.d. Natusch, Jessica A. Lyons
    Abstract:

    Prey selection in many species is known to change ontogenetically, suggesting that associated changes in trophic structure may also be important. Several studies have examined relationships between prey selection and the size of trophic structures; however, few have explored these changes over ontogeny or the effects that they may have on a species broader ecology. The present study addressed this issue by examining relationships between changes in head size and prey selection in juveniles and adults from three populations of the python Morelia viridis and related them to changes in sexual maturity and ontogenetic changes in colour (OCC). Our scaling data for head size showed that juveniles and adults scaled mostly with negative allometry, and allometric slopes were significantly different before and after OCC. The change in head shape allometry was strongly associated with changes in prey selection from ectothermic to endothermic prey and with OCC in two of the three populations studied. OCC in the other population varied widely and may be the result of isolation on an oceanic island. Negatively allometric head growth is common in vertebrates and may serve a functional role in M. viridis by reducing the maximum ingestible prey size in adults, thus aiding arboreality. Our data do not allow us to test which of these changes have causal or resultant effects on one another; however, we suggest they may be part of an overall evolutionary defence‐foraging strategy that circumvents costs imposed by restricting foraging opportunities to certain habitats. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, , ••‐••.

  • Consumer driven conservation of green pythons is possible if the price is right: A reply to Pernetta (2012)
    Biological Conservation, 2012
    Co-Authors: Jessica A. Lyons, Daniel J.d. Natusch
    Abstract:

    Preventing unsustainable and illegal trade of wildlife is vital for protecting biodiversity, yet finding ways to monitor and minimise such trade cost-effectively remains a significant challenge. Recently, Pernetta (2012) criticised our suggestion to use eggshells as a means of regulating the laundering of illegally wild-caught green pythons (Morelia viridis) through breeding farms in Indonesia viz. if a snake was bred at a farm it must have an accompanying eggshell (Lyons and Natusch 2011). Pernetta (2012) suggested that such a method may create demand for gravid females from wild populations and argued that it should not be used as the sole tool for preventing laundering. Instead, Pernetta (2012) suggested that a chain of custody should be set up whereby microsatellite genotyping and parentage assignment techniques would provide a fool-proof method of unequivocally identifying wild-caught snakes, the funding for which could be procured via a conservation tax levied from end consumers. We agree with Pernetta (2012) that the eggshell method should not be used as the sole tool, but one part of a multi tiered, integrated and holistic approach to combating illegal harvest of green pythons. Despite being omitted from Pernetta’s (2012) review, our paper also suggested several other means of minimising illegal collection; educating the consumer market, husbandry training, determining the economic viability of green python farming and allowing limited legal collection of wild individuals. The beauty of the eggshell method, however, lies in its simplicity; it is cost effective and can be implemented immediately. We argue, based on our fieldwork, that unless demand for green pythons (and therefore market price) significantly increases, the time involved in searching for gravid females makes it impractical. Indeed, of the 1733 green pythons collected by traders and thoroughly examined by us, 0.4% (7) were gravid females. While it may be naive to assume that intensive searching for selective harvests will not occur in the future, currently every snake encountered by collectors is taken for the pet trade – gravid or not. Although microsatellite genotyping and parentage assignment techniques may be a valid means of regulating illegal trade, they will take a considerable time to introduce and have significant associated cost. These techniques are currently not done for any species in Indonesia, not even those of high commercial value or those that are globally threatened, and it is a stretch to expect Indonesian authorities to introduce this system for green pythons. Further, many of the farms regularly exporting green pythons from Indonesia do not have parent stock from which to allow parentage assignment. As an initial step in monitoring and enforcement, which can be implemented immediately at minimal cost, proof of breeding (in the form of eggshells) is sufficient to identify which farms are providing fallacious breeding records. Simply the added request of enclosing eggshells (and not even measuring them) would curtail much of this trade. We suggest, therefore, that while the application of genetic forensic techniques may be more reliable than the eggshell method, the significant cost involved currently makes them impractical for regulating farming operations in Indonesia. Despite consumers preferring captive-bred green pythons over wild-caught ones (Auylia, 2003) Indonesian ‘‘farm-bred’’ snakes are attractive due to their lower market price (USD 225 compared to USD 500, respectively). Indonesian exporters currently sell snakes at these prices because of the reduced cost involved in collecting and exporting wild-caught individuals. By comparison, housing, feeding and breeding green pythons at farms may not be economically feasible if prices are not increased. Raising the price of farm-bred individuals, however, and imposing a conservation tax on their exportation will inevitably reduce demand for some snakes from Indonesia. For breeding farms to be successful, and in the presence of proper regulatory measures for preventing illegal harvests, they should provide a cheaper, more acceptable product to the consumer than wild-caught animals. Thus, for sustainable farming of green pythons, changing consumer attitudes from being price-based to conservation focussed can be achieved – but only if the price is right.

Stanislav N. Gorb - One of the best experts on this subject based on the ideXlab platform.

  • Nanoscale Pattern Formation in Biological Surfaces
    Biologically-Inspired Systems, 2020
    Co-Authors: Alexander E Filippov, Stanislav N. Gorb
    Abstract:

    In the present chapter, three problems of nanoscale pattern formation will be discussed. (1) The particular symmetry violation in the dimple-like nano-pattern on the belly scales of the pythonid snake Morelia viridis is analyzed using correlation analysis of the distances between individual nanostructures. (2) Pattern formation in the multi-component colloidal secretion of whip-spiders (cerotegument) is numerically simulated and discussed. (3) Pattern formation of the springtail cuticle nanostructures.

  • Correlation analysis of symmetry breaking in the surface nanostructure ordering: case study of the ventral scale of the snake Morelia viridis
    Applied Physics A, 2016
    Co-Authors: Alexander Kovalev, Alexander E Filippov, Stanislav N. Gorb
    Abstract:

    In contrast to the majority of inorganic or artificial materials, there is no ideal long-range ordering of structures on the surface in biological systems. Local symmetry of the ordering on biological surfaces is also often broken. In the present paper, the particular symmetry violation was analyzed for dimple-like nano-pattern on the belly scales of the skin of the pythonid snake Morelia viridis using correlation analysis and statistics of the distances between individual nanostructures. The results of the analysis performed on M. viridis were compared with a well-studied nano-nipple pattern on the eye of the sphingid moth Manduca sexta, used as a reference. The analysis revealed non-random, but very specific symmetry violation. In the case of the moth eye, the nano-nipple arrangement forms a set of domains, while in the case of the snake skin, the nano-dimples arrangement resembles an ordering of particles (molecules) in amorphous (glass) state. The function of the nano-dimples arrangement may be to provide both friction and strength isotropy of the skin. A simple model is suggested, which provides the results almost perfectly coinciding with the experimental ones. Possible mechanisms of the appearance of the above nano-formations are discussed.

  • Scratch resistance of the ventral skin surface in four snake species (Squamata, Serpentes).
    Zoology, 2016
    Co-Authors: Mariechristin G Klein, Stanislav N. Gorb
    Abstract:

    Snakes are limbless tetrapods highly specialized for sliding locomotion on various substrates. Their skin is constantly exposed to high friction forces, which promotes abrasion. Snake skin has material and surface specializations, presumably optimized for friction and abrasion resistance. We found that different snake species living in different habitats have different abrasion patterns and hypothesized that this correlates with specific epidermal architecture and surface topography. To test this hypothesis artificial scratches, under controlled load conditions, were created on the ventral skin material (epidermis) of four snake species adapted to different habitats: Lampropeltis getula californiae (stony and sandy soil substrates), Epicrates cenchria cenchria (trees, soil and water), Morelia viridis (trees), and Gongylophis colubrinus (burrowing in sand). Abrasion appearance on the skin surface was examined using scanning electron microscopy and white light interferometry. The material failure was different between the species, which we attribute to differences in the epidermis' response to the same abrasive challenge. We also discuss abrasion resistance mechanisms and the correlation with the different ultrastructure and surface microstructure.

  • Ultrastructure and wear patterns of the ventral epidermis of four snake species (Squamata, Serpentes).
    Zoology, 2014
    Co-Authors: Mariechristin G Klein, Stanislav N. Gorb
    Abstract:

    Snakes are limbless tetrapods highly specialized for sliding locomotion. This locomotion leads to the skin being exposed to friction loads, especially on the ventral body side, which leads to wear. It is presumed that snakes therefore have specific optimizations for minimizing abrasion. Scales from snakes with habitat, locomotor and/or behavior specializations have specific gradients in material properties that may be due to different epidermal architecture. To approach this issue we examined the skin of Lampropeltis getula californiae (terrestrial), Epicrates cenchria cenchria (generalist), Morelia viridis (arboreal), and Gongylophis colubrinus (burrowing) with a focus on (i) the ultrastructure of the ventral epidermis and (ii) the qualitative abrasion pattern of the ventral scales. Scanning and transmission electron microscopy revealed variations in the structure, thickness, layering, and material composition of the epidermis between the species. Furthermore, SEM and white light interferometer images of the scale surface showed that the abrasion patterns differed, even when the snakes were reared on the same substrate. These data support the idea that (i) a specific gradient in material properties may be due to a variation in epidermis architecture (thickness/ultrastructure) and (ii) this variation may be an optimization of material properties for specific ways of life. (C) 2014 Elsevier GmbH. All rights reserved.

  • epidermis architecture and material properties of the skin of four snake species
    Journal of the Royal Society Interface, 2012
    Co-Authors: Mariechristin G Klein, Stanislav N. Gorb
    Abstract:

    On the basis of structural and experimental data, it was previously demonstrated that the snake integument consists of a hard, robust, inflexible outer surface (Oberhautchen and β-layer) and softer, flexible inner layers (α-layers). It is not clear whether this phenomenon is a general adaptation of snakes to limbless locomotion or only to specific conditions, such as habitat and locomotion. The aim of the present study was to compare the structure and material properties of the outer scale layers (OSLs) and inner scale layers (ISLs) of the exuvium epidermis in four snake species specialized to live in different habitats: Lampropeltis getula californiae (terrestrial), Epicrates cenchria cenchria (generalist), Morelia viridis (arboreal) and Gongylophis colubrinus (sand-burrowing). Scanning electron microscopy (SEM) of skin cross sections revealed a strong variation in the epidermis structure between species. The nanoindentation experiments clearly demonstrated a gradient of material properties along the epidermis in the integument of all the species studied. The presence of such a gradient is a possible adaptation to locomotion and wear minimization on natural substrates. In general, the difference in both the effective elastic modulus and hardness of the OSL and ISL between species was not large compared with the difference in epidermis thickness and architecture.

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

  • Species delimitation and systematics of the green pythons (Morelia viridis complex) of melanesia and Australia.
    Molecular phylogenetics and evolution, 2019
    Co-Authors: Daniel J.d. Natusch, Damien Esquerré, Jessica A. Lyons, Amir Hamidy, Alan R. Lemmon, Emily Moriarty Lemmon, Awal Riyanto, J. Scott Keogh, Stephen C. Donnellan
    Abstract:

    Abstract Molecular data sets and the increasing use of integrative systematics is revealing cryptic diversity in a range of taxa – particularly in remote and poorly sampled landscapes like the island of New Guinea. Green pythons (Morelia viridis complex) are one of the most conspicuous elements of this island’s fauna, with large numbers taken from the wild to supply international demand for exotic pets. We test hypotheses about species boundaries in green pythons from across New Guinea and Australia with mitochondrial genomes, 389 nuclear exons, and comprehensive assessment of morphological variation. Strong genetic structuring of green python populations and species delimitation methods confirm the presence of two species, broadly occurring north and south of New Guinea’s central mountains. Our data also support three subspecies within the northern species. Subtle but consistent morphological divergence among the putative taxa is concordant with patterns of molecular divergence. Our extensive sampling identifies several zones of hitherto unknown biogeographical significance on the island of New Guinea. We revise the taxonomy of the group, discuss the relevance of our findings in the context of Papuan biogeography and the implications of our systematic changes for the conservation management of these taxa.

  • Phylogeographic analysis of the green python, Morelia viridis, reveals cryptic diversity
    Molecular phylogenetics and evolution, 2003
    Co-Authors: Lesley H. Rawlings, Stephen C. Donnellan
    Abstract:

    Green pythons, which are regionally variable in colour patterns, are found throughout the lowland rainforest of New Guinea and adjacent far northeastern Australia. The species is popular in commercial trade and management of this trade and its impacts on natural populations could be assisted by molecular identification tools. We used mitochondrial nucleotide sequences and a limited allozyme data to test whether significantly differentiated populations occur within the species range. Phylogenetic analysis of mtDNA sequences revealed hierarchal phylogeographic structure both within New Guinea and between New Guinea and Australia. Strongly supported reciprocally monophyletic mitochondrial lineages, northern and southern, were found either side of the central mountain range that runs nearly the length of New Guinea. Limited allozyme data suggest that population differentiation is reflected in the nuclear as well as the mitochondrial genome. A previous morphological analysis did not find any phenotypic concordance with the pattern of differentiation observed in the molecular data. The southern mitochondrial lineage includes all of the Australian haplotypes, which form a single lineage, nested among the southern New Guinean haplotypes.

Anja Kipar - One of the best experts on this subject based on the ideXlab platform.

  • Serpentoviruses: More than Respiratory Pathogens.
    Journal of virology, 2020
    Co-Authors: Eva Dervas, Jussi Hepojoki, Teemu Smura, Udo Hetzel, Barbara Prähauser, Katharina Windbichler, Sandra Blümich, Antonio Ramis, Anja Kipar
    Abstract:

    In recent years, nidoviruses have emerged as important respiratory pathogens of reptiles, affecting captive python populations. In pythons, nidovirus (recently reclassified as serpentovirus) infection induces an inflammation of the upper respiratory and alimentary tract which can develop into a severe, often fatal proliferative pneumonia. We observed pyogranulomatous and fibrinonecrotic lesions in organ systems other than the respiratory tract during full postmortem examinations on 30 serpentovirus reverse transcription-PCR (RT-PCR)-positive pythons of varying species originating from Switzerland and Spain. The observations prompted us to study whether this not yet reported wider distribution of lesions is associated with previously unknown serpentoviruses or changes in the serpentovirus genome. RT-PCR and inoculation of Morelia viridis cell cultures served to recruit the cases and obtain virus isolates. Immunohistochemistry and immunofluorescence staining against serpentovirus nucleoprotein demonstrated that the virus infects not only a broad spectrum of epithelia (respiratory and alimentary epithelium, hepatocytes, renal tubules, pancreatic ducts, etc.), but also intravascular monocytes, intralesional macrophages, and endothelial cells. With next-generation sequencing we obtained a full-length genome for a novel serpentovirus species circulating in Switzerland. Analysis of viral genomes recovered from pythons showing serpentovirus infection-associated respiratory or systemic disease did not reveal sequence association to phenotypes; however, functional studies with different strains are needed to confirm this observation. The results indicate that serpentoviruses have a broad cell and tissue tropism, further suggesting that the course of infection could vary and involve lesions in a broad spectrum of tissues and organ systems as a consequence of monocyte-mediated viral systemic spread.IMPORTANCE During the last years, python nidoviruses (now reclassified as serpentoviruses) have become a primary cause of fatal disease in pythons. Serpentoviruses represent a threat to captive snake collections, as they spread rapidly and can be associated with high morbidity and mortality. Our study indicates that, different from previous evidence, the viruses do not only affect the respiratory tract, but can spread in the entire body with blood monocytes, have a broad spectrum of target cells, and can induce a variety of lesions. Nidovirales is an order of animal and human viruses that comprises important zoonotic pathogens such as Middle East respiratory syndrome coronavirus (MERS-CoV), severe acute respiratory syndrome coronavirus (SARS-CoV), and SARS-CoV-2. Serpentoviruses belong to the same order as the above-mentioned human viruses and show similar characteristics (rapid spread, respiratory and gastrointestinal tropism, etc.). The present study confirms the relevance of natural animal diseases to better understand the complexity of viruses of the order Nidovirales.

  • Python nidoviruses, more than respiratory pathogens
    2020
    Co-Authors: Eva Dervas, Jussi Hepojoki, Teemu Smura, Udo Hetzel, Barbara Prähauser, Katharina Windbichler, Sandra Blümich, Antonio Ramis, Anja Kipar
    Abstract:

    In recent years nidoviruses have emerged as an important respiratory pathogen of reptiles, affecting especially captive python populations. In pythons, nidovirus infection induces an inflammation of the upper respiratory and alimentary tract which can develop into a severe and often fatal proliferative pneumonia. We observed pyogranulomatous and fibrinonecrotic lesions in organ systems other than the respiratory tract during full post mortem examinations on 30 nidovirus RT-PCR positive pythons of varying species originating from Switzerland and Spain. The observations prompted us to study whether the atypical tissue tropism associates with previously unknown nidoviruses or changes in the nidovirus genome. RT-PCR and inoculation of Morelia viridis cell cultures served to recruit the cases and to obtain virus isolates. Immunohistochemistry and immunofluorescence staining against nidovirus nucleoprotein demonstrated that the virus not only infects a broad spectrum of epithelial (respiratory and alimentary epithelium, hepatocytes, renal tubules, pancreatic ducts etc.), but also intravascular monocytes, intralesional macrophages and endothelial cells. By next-generation sequencing we obtained full length genome for a novel nidovirus species circulating in Switzerland. Analysis of viral genomes recovered from pythons showing nidovirus infection-associated respiratory or systemic disease did not explain the observed phenotypes. The results indicate that python nidoviruses have a broad cell and tissue tropism, further suggesting that the course of infection could vary and involve lesions in a broad spectrum of tissues and organ systems as a consequence of monocyte-mediated systemic spread of the virus.

  • Python nidoviruses, more than respiratory pathogens
    2020
    Co-Authors: Eva Dervas, Jussi Hepojoki, Teemu Smura, Udo Hetzel, Barbara Prähauser, Katharina Windbichler, Sandra Blümich, Antonio Ramis, Anja Kipar
    Abstract:

    ABSTRACTIn recent years nidoviruses have emerged as an important respiratory pathogen of reptiles, affecting especially captive python populations. In pythons, nidovirus infection induces an inflammation of the upper respiratory and alimentary tract which can develop into a severe and often fatal proliferative pneumonia. We observed pyogranulomatous and fibrinonecrotic lesions in organ systems other than the respiratory tract during full post mortem examinations on 30 nidovirus RT-PCR positive pythons of varying species originating from Switzerland and Spain. The observations prompted us to study whether the atypical tissue tropism associates with previously unknown nidoviruses or changes in the nidovirus genome. RT-PCR and inoculation of Morelia viridis cell cultures served to recruit the cases and to obtain virus isolates. Immunohistochemistry and immunofluorescence staining against nidovirus nucleoprotein demonstrated that the virus not only infects a broad spectrum of epithelial (respiratory and alimentary epithelium, hepatocytes, renal tubules, pancreatic ducts etc.), but also intravascular monocytes, intralesional macrophages and endothelial cells. By next-generation sequencing we obtained full length genome for a novel nidovirus species circulating in Switzerland. Analysis of viral genomes recovered from pythons showing nidovirus infection-associated respiratory or systemic disease did not explain the observed phenotypes. The results indicate that python nidoviruses have a broad cell and tissue tropism, further suggesting that the course of infection could vary and involve lesions in a broad spectrum of tissues and organ systems as a consequence of monocyte-mediated systemic spread of the virus.IMPORTANCEDuring the last years, python nidoviruses have become a primary cause of fatal disease in pythons. Nidoviruses represent a threat to captive snake collections, as they spread rapidly and can be associated with high morbidity and mortality. Our study indicates that, different from previously evidence, the viruses do not only affect the respiratory tract, but can spread in the entire body with blood monocytes, have a broad spectrum of target cells, and can induce a variety of lesions. Nidovirales is an order of animal and human viruses that compromise important zoonotic pathogens such as MERS-CoV and SARS-CoV, as well as the recently emerged SARS-CoV-2. Python nidoviruses belong to the same subfamily as the mentioned human viruses and show similar characteristics (rapid spread, respiratory and gastrointestinal tropism, etc.). The present study confirms the relevance of natural animal diseases to better understand the complexity of viruses of the order nidovirales.

  • nidovirus associated proliferative pneumonia in the green tree python Morelia viridis
    Journal of Virology, 2017
    Co-Authors: Eva Dervas, Jussi Hepojoki, Andrea S Laimbacher, Fernando Romeropalomo, C Jelinek, Saskia Keller, Teemu Smura, Satu Hepojoki, Anja Kipar
    Abstract:

    In 2014 we observed a noticeable increase in the number of sudden deaths among green tree pythons (Morelia viridis). Pathological examination revealed the accumulation of mucoid material within the airways and lungs in association with enlargement of the entire lung. We performed a full necropsy and histological examination on 12 affected green tree pythons from 7 different breeders to characterize the pathogenesis of this mucinous pneumonia. By histology we could show a marked hyperplasia of the airway epithelium and of faveolar type II pneumocytes. Since routine microbiological tests failed to identify a causative agent, we studied lung tissue samples from a few diseased snakes by next-generation sequencing (NGS). From the NGS data we could assemble a piece of RNA genome whose sequence was <85% identical to that of nidoviruses previously identified in ball pythons and Indian pythons. We then employed reverse transcription-PCR to demonstrate the presence of the novel nidovirus in all diseased snakes. To attempt virus isolation, we established primary cultures of Morelia viridis liver and brain cells, which we inoculated with homogenates of lung tissue from infected individuals. Ultrastructural examination of concentrated cell culture supernatants showed the presence of nidovirus particles, and subsequent NGS analysis yielded the full genome of the novel virus Morelia viridis nidovirus (MVNV). We then generated an antibody against MVNV nucleoprotein, which we used alongside RNA in situ hybridization to demonstrate viral antigen and RNA in the affected lungs. This suggests that in natural infection MVNV damages the respiratory tract epithelium, which then results in epithelial hyperplasia, most likely as an exaggerated regenerative attempt in association with increased epithelial turnover.IMPORTANCE Novel nidoviruses associated with severe respiratory disease were fairly recently identified in ball pythons and Indian pythons. Herein we report on the isolation and identification of a further nidovirus from green tree pythons (Morelia viridis) with fatal pneumonia. We thoroughly characterized the pathological changes in the infected individuals and show that nidovirus infection is associated with marked epithelial proliferation in the respiratory tract. We speculate that this and the associated excess mucus production can lead to the animals' death by inhibiting normal gas exchange in the lungs. The virus was predominantly detected in the respiratory tract, which renders transmission via the respiratory route likely. Nidoviruses cause sudden outbreaks with high rates of mortality in breeding collections, and most affected snakes die without prior clinical signs. These findings, together with those of other groups, indicate that nidoviruses are a likely cause of severe pneumonia in pythons.

  • Nidovirus-Associated Proliferative Pneumonia in the Green Tree Python (Morelia viridis)
    Journal of virology, 2017
    Co-Authors: Eva Dervas, Jussi Hepojoki, Andrea S Laimbacher, C Jelinek, Saskia Keller, Teemu Smura, Satu Hepojoki, Anja Kipar, Fernando Romero-palomo, Udo Hetzel
    Abstract:

    In 2014 we observed a noticeable increase in the number of sudden deaths among green tree pythons (Morelia viridis). Pathological examination revealed the accumulation of mucoid material within the airways and lungs in association with enlargement of the entire lung. We performed a full necropsy and histological examination on 12 affected green tree pythons from 7 different breeders to characterize the pathogenesis of this mucinous pneumonia. By histology we could show a marked hyperplasia of the airway epithelium and of faveolar type II pneumocytes. Since routine microbiological tests failed to identify a causative agent, we studied lung tissue samples from a few diseased snakes by next-generation sequencing (NGS). From the NGS data we could assemble a piece of RNA genome whose sequence was