Geographic and taxonomic patterns of extinction risk in Australian squamates

Viral pathogens are being increasingly described in association with mass morbidity and mortality events in reptiles. However, our knowledge of reptile viruses remains limited. Herein, we describe the meta-transcriptomic investigation of a mass morbidity and mortality event in a colony of central bearded dragons (Pogona vitticeps) in 2014. Severe, extensive proliferation of the respiratory epithelium was consistently found in affected dragons. Similar proliferative lung lesions were identified in bearded dragons from the same colony in 2020 in association with increased intermittent mortality. Total RNA sequencing identified two divergent DNA viruses: a reptile-infecting circovirus, denoted bearded dragon circovirus (BDCV), and the first exogeneous reptilian chaphamaparvovirus—bearded dragon chaphamaparvovirus (BDchPV). Phylogenetic analysis revealed that BDCV was most closely related to bat-associated circoviruses, exhibiting 70% amino acid sequence identity in the Replicase (Rep) protein. In contrast, in the nonstructural (NS) protein, the newly discovered BDchPV showed approximately 31%–35% identity to parvoviruses obtained from tilapia fish and crocodiles in China. Subsequent specific PCR assays revealed BDCV and BDchPV in both diseased and apparently normal captive reptiles, although only BDCV was found in those animals with proliferative pulmonary lesions and respiratory disease. This study expands our understanding of viral diversity in captive reptiles.

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“…Squamates (scaled reptiles) are one of the most diverse groups of vertebrate fauna in Australia [ 1 ]. Bearded dragons ( Pogona spp.…”

Section: Introductionmentioning

confidence: 99%

Meta-Transcriptomic Discovery of a Divergent Circovirus and a Chaphamaparvovirus in Captive Reptiles with Proliferative Respiratory Syndrome

Chang

Hall

et al. 2020

Viruses

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“…We excluded the following species because no specimens were available: Cyrtodactylus kimberleyensis and Diplodactylus kenneallyi (known only from their holotypes), Strophurus rankini , Gehyra pulingka and Aprasia picturata . To account for potential taxonomic issues, all museum specimen records acquired from the Online Zoological Collections of Australian Museums (https://www.ozcam.org.au/) were georeferenced in q GIS v3.6.2 (https://qgis.org/en/site/) against expert verified distributional data collated as part of the 2017 International Union for Conservation of Nature (IUCN) Red List assessment of all Australian squamates (Chapple et al., 2019; IUCN, 2019; Tingley et al., 2019). Specimens within the distributional polygons were preferentially chosen to minimize potential taxonomic issues.…”

Section: Methodsmentioning

confidence: 99%

Environmental correlates of morphological diversity in Australian geckos

Norris

Tingley

Meiri

et al. 2021

Global Ecol. Biogeogr.

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Aim Climatic variation has long been regarded as a primary source of morphological variation. However, there is mixed support for the adherence of reptiles to ecogeographical hypotheses, such as Bergmann’s rule (body size decreases with temperature) and Allen’s rule (limb length increases with temperature). We quantified body and limb morphology among the diverse Australian gecko fauna (4 families, 30 genera, 226 of the 231 described species) to investigate environmental correlates of morphological variation in this radiation. Location Australia. Major taxa studied Geckos (Squamata: Gekkota; the families Gekkonidae, Carphodactylidae, Diplodactylidae and Pygopodidae). Methods We measured 20 external features of ethanol‐preserved museum specimens. We investigated whether principal component axes of morphology were correlated with three key environmental variables, and the microhabitat occupied by each species. Results Morphology varied greatly among Australian gecko families and genera, although there was a strong phylogenetic signal in morphology. After accounting for phylogeny, morphology was correlated with a species’ microhabitat use. Saxicolous species and species with variable microhabitat requirements (i.e., generalists) had larger body dimensions than terrestrial species. Saxicolous species also had longer proportional forelimbs and hindlimbs than terrestrial species. Main conclusions Our results highlight the importance of phylogeny and microhabitat use in shaping the morphology of Australian geckos. We find little evidence that Australian geckos adhere to Bergmann’s rule or Allen’s rule, suggesting that these ecogeographical hypotheses provide limited insight into the adaptive potential of lizard species to altered environmental conditions.

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“…Currently, most of the information we have on the extent of this pressure comes from seizures and the presence of Australian reptile species in overseas markets 2 , 15 , 20 . Unfortunately, because we only have a limited understanding of the population dynamics of most Australian reptiles, and the threatening processes that affect them 22 , 23 , there is often insufficient information to assess the effects of illegal collecting on local populations.…”

Section: Introductionmentioning

confidence: 99%

“…Species at a high trophic level, low population density, small geographic range size and/or slow life history are already predisposed to increased risk of extinction 27 , and long-lived species with slow growth rates, infrequent reproduction, and small litter sizes are likely susceptible to overharvesting. Unfortunately, we know so little about the threats to most Australian reptiles 22 , 28 , 29 that it is difficult to ascertain which species may be most vulnerable to the impacts of illegal collecting. One notable exception is the threatened broad-headed snake ( Hoplocephalus bungaroides ) (IUCN status: Vulnerable; Australian Commonwealth status: Vulnerable; NSW status: Endangered), a species endemic to the Sydney region of south-eastern Australia, which has been extensively studied over the last few decades (e.g.…”

Section: Introductionmentioning

confidence: 99%

Slow life history leaves endangered snake vulnerable to illegal collecting

Jolly

Takach

Webb

2021

Sci Rep

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Global wildlife trade is a multibillion-dollar industry and a significant driver of vertebrate extinction risk. Yet, few studies have quantified the impact of wild harvesting for the illicit pet trade on populations. Long-lived species, by virtue of their slow life history characteristics, may be unable to sustain even low levels of collecting. Here, we assessed the impact of illegal collecting on populations of endangered broad-headed snakes (Hoplocephalus bungaroides) at gated (protected) and ungated (unprotected) sites. Because broad-headed snakes are long-lived, grow slowly and reproduce infrequently, populations are likely vulnerable to increases in adult mortality. Long-term data revealed that annual survival rates of snakes were significantly lower in the ungated population than the gated population, consistent with the hypothesis of human removal of snakes for the pet trade. Population viability analysis showed that the ungated population has a strongly negative population growth rate and is only prevented from ultimate extinction by dispersal of small numbers of individuals from the gated population. Sensitivity analyses showed that the removal of a small number of adult females was sufficient to impose negative population growth and suggests that threatened species with slow life histories are likely to be especially vulnerable to illegal collecting.

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Geographic and taxonomic patterns of extinction risk in Australian squamates

Abstract: for providing expert advice during the post-workshop review stage. We thank the experts involved in the New Guinea assessment workshop, for their information on species with distributions spanning Torres

Cited by 53 publications

References 29 publications

Meta-Transcriptomic Discovery of a Divergent Circovirus and a Chaphamaparvovirus in Captive Reptiles with Proliferative Respiratory Syndrome

Meta-Transcriptomic Discovery of a Divergent Circovirus and a Chaphamaparvovirus in Captive Reptiles with Proliferative Respiratory Syndrome

Environmental correlates of morphological diversity in Australian geckos

Slow life history leaves endangered snake vulnerable to illegal collecting

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