ORCID Profile
0000-0002-9904-1501
Current Organisations
Flinders University
,
University of Sydney
,
Macquarie University
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Publisher: Springer Science and Business Media LLC
Date: 19-10-2015
DOI: 10.1038/NATURE13825
Abstract: Reproduction in jawed vertebrates (gnathostomes) involves either external or internal fertilization. It is commonly argued that internal fertilization can evolve from external, but not the reverse. Male copulatory claspers are present in certain placoderms, fossil jawed vertebrates retrieved as a paraphyletic segment of the gnathostome stem group in recent studies. This suggests that internal fertilization could be primitive for gnathostomes, but such a conclusion depends on demonstrating that copulation was not just a specialized feature of certain placoderm subgroups. The reproductive biology of antiarchs, consistently identified as the least crownward placoderms and thus of great interest in this context, has until now remained unknown. Here we show that certain antiarchs possessed dermal claspers in the males, while females bore paired dermal plates inferred to have facilitated copulation. These structures are not associated with pelvic fins. The clasper morphology resembles that of ptyctodonts, a more crownward placoderm group, suggesting that all placoderm claspers are homologous and that internal fertilization characterized all placoderms. This implies that external fertilization and spawning, which characterize most extant aquatic gnathostomes, must be derived from internal fertilization, even though this transformation has been thought implausible. Alternatively, the substantial morphological evidence for placoderm paraphyly must be rejected.
Publisher: SAGE Publications
Date: 13-06-2019
Abstract: This article explores street-level discretion of Australian welfare workers when working with clients from culturally and linguistically erse (CALD) backgrounds. The research is situated within the context of New Public Management (NPM) and neoliberalism in the welfare sector. Findings suggest that workers’ discretion oscillates between extra support for clients, or further scrutiny and sanction. Such contradictory patterns of discretion highlight workers’ capacity to resist neoliberalism while concurrently upholding it. The article argues that cultural understanding, recognition of the limitations in welfare-to-work policies and neoliberalism, and how those factors, together with ethnicity, may influence street-level discretion are necessary for welfare workers to support CALD clients effectively.
Publisher: Wiley
Date: 05-2009
Publisher: Informa UK Limited
Date: 22-05-2017
Publisher: Wiley
Date: 19-04-2018
DOI: 10.1002/AJS4.35
Publisher: eLife Sciences Publications, Ltd
Date: 29-05-2018
DOI: 10.7554/ELIFE.34349
Abstract: The skull of ‘Ligulalepis’ from the Early Devonian of Australia (AM-F101607) has significantly expanded our knowledge of early osteichthyan anatomy, but its phylogenetic position has remained uncertain. We herein describe a second skull of ‘Ligulalepis’ and present micro-CT data on both specimens to reveal novel anatomical features, including cranial endocasts. Several features previously considered to link ‘Ligulalepis’ with actinopterygians are now considered generalized osteichthyan characters or of uncertain polarity. The presence of a lateral cranial canal is shown to be variable in its development between specimens. Other notable new features include the presence of a pineal foramen, the some detail of skull roof sutures, the shape of the nasal capsules, a placoderm-like hypophysial vein, and a chondrichthyan-like labyrinth system. New phylogenetic analyses place ‘Ligulalepis’ as a stem osteichthyan, specifically as the sister taxon to ‘psarolepids’ plus crown osteichthyans. The precise position of ‘psarolepids’ differs between parsimony and Bayesian analyses.
Publisher: Wiley
Date: 16-12-2018
DOI: 10.1002/SPP2.1243
Publisher: Cambridge University Press (CUP)
Date: 27-03-2008
DOI: 10.1017/S0954102008001144
Abstract: A new basal actinopterygian fish, Donnrosenia schaefferi gen. et sp. nov., is described from the Middle Devonian (Givetian) Aztec Siltstone of southern Victoria Land, Antarctica. Donnrosenia gen. nov. is characterized by the large parietals which are of almost equivalent size to the frontals, very small intertemporals, a small accessory operculum situated dorsally to the prominent anterodorsal process of the suboperculum, a deep dentary with anterior flexure, porous ornamentation on the clavicle, an elongate body form with macromeric squamation, an absence of paired fringing fulcra on the fins, and pectoral lepidotrichia which are unsegmented for much of their length. A phylogenetic analysis based on dermal skeletal features of Devonian actinopterygians indicates that Donnrosenia gen. nov. is the sister taxon to Howqualepis from the Middle Devonian of Victoria, Australia, and is embedded within a possible clade containing the actinopterygians from the Gogo Formation, Western Australia. This supports the concept of an endemic radiation of East Gondwanan actinopterygians, and reinforces the already strong biogeographical similarities between the Middle Devonian palaeofaunas of Australia and Antarctica.
Publisher: Elsevier BV
Date: 03-2010
Publisher: Cambridge University Press (CUP)
Date: 03-2018
DOI: 10.1017/S1755691018000750
Abstract: The earliest tetrapodomorph fishes appear in Chinese deposits of Early Devonian age, and by the Middle Devonian they were widespread globally. Evidence for the earliest digitated tetrapods comes from largely uncontested Middle Devonian trackways and Late Devonian body fossils. The East Gondwana Provence (Australasia, Antarctica) fills vital gaps in the phylogenetic and biogeographic history of the tetrapods, with the Gondwanan clade Canowindididae exhibiting a high degree of endemism within the early part of the stem tetrapod radiation. New anatomical details of Koharalepis , from the Middle Devonian Aztec Siltstone of Antarctica, are elucidated from synchrotron scan data. These include the position of the orbit, the condition of the hyomandibular, the shape of the palate and arrangement of the vomerine fangs. Biogeographical and phylogenetic models of stem tetrapod origins and radiations are discussed.
No related grants have been discovered for Tran Nguyen.