Dragon's Paradise Lost: Palaeobiogeography, Evolution and Extinction of the Largest-Ever Terrestrial Lizards (Varanidae)

BACKGROUND: The largest living lizard species, Varanus komodoensis Ouwens 1912, is vulnerable to extinction, being restricted to a few isolated islands in eastern Indonesia, between Java and Australia, where it is the dominant terrestrial carnivore. Understanding how large-bodied varanids responded to past environmental change underpins long-term management of V. komodoensis populations. METHODOLOGY/PRINCIPAL FINDINGS: We reconstruct the palaeobiogeography of Neogene giant varanids and identify a new (unnamed) species from the island of Timor. Our data reject the long-held perception that V. komodoensis became a giant because of insular evolution or as a specialist hunter of pygmy Stegodon. Phyletic giantism, coupled with a westward dispersal from mainland Australia, provides the most parsimonious explanation for the palaeodistribution of V. komodoensis and the newly identified species of giant varanid from Timor. Pliocene giant varanid fossils from Australia are morphologically referable to V. komodoensis suggesting an ultimate origin for V. komodoensis on mainland Australia (>3.8 million years ago). Varanus komodoensis body size has remained stable over the last 900,000 years (ka) on Flores, a time marked by major faunal turnovers, extinction of the island's megafauna, the arrival of early hominids by 880 ka, co-existence with Homo floresiensis, and the arrival of modern humans by 10 ka. Within the last 2000 years their populations have contracted severely. CONCLUSIONS/SIGNIFICANCE: Giant varanids were once a ubiquitous part of Subcontinental Eurasian and Australasian faunas during the Neogene. Extinction played a pivotal role in the reduction of their ranges and diversity throughout the late Quaternary, leaving only V. komodoensis as an isolated long-term survivor. The events over the last two millennia now threaten its future survival

A new giant sauropod, Australotitan cooperensis gen. et sp. nov., from the mid-Cretaceous of Australia

A new giant sauropod, Australotitan cooperensis gen. et sp. nov., represents the first record of dinosaurs from the southern-central Winton Formation of the Eromanga Basin, Australia. We estimate the type locality to be 270–300 m from the base of the Winton Formation and compare this to the semi-contemporaneous sauropod taxa, Diamantinasaurus matildae Hocknull et al., 2009, Wintonotitan wattsi Hocknull et al., 2009 and Savannasaurus elliottorum Poropat et al., 2016. The new titanosaurian is the largest dinosaur from Australia as represented by osteological remains and based on limb-size comparisons it reached a size similar to that of the giant titanosaurians from South America. Using 3-D surface scan models we compare features of the appendicular skeleton that differentiate Australotitan cooperensis gen. et sp. nov. as a new taxon. A key limitation to the study of sauropods is the inability to easily and directly compare specimens. Therefore, 3-D cybertypes have become a more standard way to undertake direct comparative assessments. Uncoloured, low resolution, and uncharacterized 3-D surface models can lead to misinterpretations, in particular identification of pre-, syn- and post-depositional distortion. We propose a method for identifying, documenting and illustrating these distortions directly onto the 3-D geometric surface of the models using a colour reference scheme. This new method is repeatable for researchers when observing and documenting specimens including taphonomic alterations and geometric differences. A detailed comparative and preliminary computational phylogenetic assessment supports a shared ancestry for all four Winton Formation taxa, albeit with limited statistical support. Palaeobiogeographical interpretations from these resultant phylogenetic hypotheses remain equivocal due to contrary Asian and South American relationships with the Australian taxa. Temporal and palaeoenvironmental differences between the northern and southern-central sauropod locations are considered to explain the taxonomic and morphological diversity of sauropods from the Winton Formation. Interpretations for this diversity are explored, including an eco-morphocline and/or chronocline across newly developed terrestrial environments as the basin fills

The architecture of cancellous bone in the hindlimb of moa (Aves: Dinornithiformes), with implications for stance and gait

The extinct, flightless moa of New Zealand included some of the largest birds to have existed and possessed many distinguishing pelvic and hindlimb osteological features. These features may have influenced stance and gait in moa compared with extant birds. One means of assessing locomotor biomechanics, particularly for extinct species, is quantitative analysis of the architecture of cancellous bone, since this architecture is adapted to suit its mechanical environment with high sensitivity. This study investigated the three-dimensional architecture of cancellous bone in the femur, tibiotarsus and fibula of three moa species: Dinornis robustus, Pachyornis elephantopus and Megalapteryx didinus. Using computed tomographic X-ray scanning and previously developed fabric analysis techniques, the spatial variation in cancellous bone fabric patterns in moa was found to be largely comparable with that previously reported for extant birds, particularly large species. Moa hence likely used postures and kinematics similar to those employed by large extant bird species, but this interpretation is tentative on account of relatively small sample sizes. A point of major difference between moa and extant birds concerns the diaphyses; cancellous bone invades the medullary cavity in both groups, but the invasion is far more extensive in moa. Combined with previous assessments of cortical geometry, this further paints a picture of at least some moa species possessing very robust limb bones, for which a convincing explanation remains to be determine

New Forearm Elements Discovered of Holotype Specimen Australovenator wintonensis from Winton, Queensland, Australia

New skeletal elements are reported of the holotype specimen Australovenator wintonensis, from the type locality, near Winton, central western Queensland. New elements include left and right humeri, right radius, right radiale, right distal carpal 1, near complete right metacarpal I, left manual phalanx II-1, left manual phalanx II-2, near complete left manual phalanx II-3 and a left manual phalanx III-3. These new elements combined with those previously described are compared against other neovenatorids

Extinction of eastern Sahul megafauna coincides with sustained environmental deterioration

Abstract: Explanations for the Upper Pleistocene extinction of megafauna from Sahul (Australia and New Guinea) remain unresolved. Extinction hypotheses have advanced climate or human-driven scenarios, in spite of over three quarters of Sahul lacking reliable biogeographic or chronologic data. Here we present new megafauna from north-eastern Australia that suffered extinction sometime after 40,100 (±1700) years ago. Megafauna fossils preserved alongside leaves, seeds, pollen and insects, indicate a sclerophyllous forest with heathy understorey that was home to aquatic and terrestrial carnivorous reptiles and megaherbivores, including the world’s largest kangaroo. Megafauna species diversity is greater compared to southern sites of similar age, which is contrary to expectations if extinctions followed proposed migration routes for people across Sahul. Our results do not support rapid or synchronous human-mediated continental-wide extinction, or the proposed timing of peak extinction events. Instead, megafauna extinctions coincide with regionally staggered spatio-temporal deterioration in hydroclimate coupled with sustained environmental change

Additional specimens of Bohra (Marsupialia: Macropodidae) from the Pliocene of Queensland

Volume: 51Start Page: 26End Page: 2

Loandalia fredrayorum Marks & Hocknull, 2006, sp. nov.

Loandalia fredrayorum sp. nov. Fig. 2, a–d. Etymology: For Frederick Marks and Raymond Fitzgerald. Material: Holotype. QMC G 223179, Loandalia fredrayorum sp. nov. [Middle Banks Moreton Bay, S 27 ° 12 ’, E 153 ° 19 ’, collected July/ August 1982]. Paratype. QMC G 223180 [Middle Banks Moreton Bay, S 27 ° 12 ’, E 153 ° 19 ’, July/ August 1982]. Habitat is a submerged sandbank with a depth of 3– 11 m. Diagnosis: Singular palpostyles. Parapodia uniramous on chaetiger 1, thereafter biramous; notopodial spine emergent at chaetiger 9; notopodial chaetae numbering 2–4; neurochaetae numbering 20–24; ventral cirri from chaetiger 7; dorsally positioned anus with two lateral papillae­like anal cirri. Description: Pilargid of large size, length 181mm, width 1.85mm (without chaetae), 2.55 (with chaetae); 218 chaetigers. Body of preserved individuals creamy/white to reddish/brown. Body corpulent; posterior segments slightly dorso­ventrally flattened. Chaetiger 1–6 inflated, with segmentation inconspicuous, surface areolated; lateral­grooves extend from first parapodia to pygidium (Fig 2, a). Prostomium discrete; palpophores divided; palpostyles are singular and papillae­like. Pharynx eversible; eye spots absent. First parapodium uniramous with remaining chaetigers biramous; notopodial lobes present at chaetiger 2, fully developed by chaetiger 6; 2–4 notochaetae present from chaetiger 2; notopodial spines weakly emerging at chaetiger 9, fully emergent at chaetiger 46. Neuropodial lobe larger than notopodia, reduced in chaetiger 1–4; simple curved neurochaetae with numerous whorled teeth; Neurochaetae in 5–6 bundles of 4, totalling 20–24 neurochaetae per parapodia; emergent neuroacicula from chaetiger 1, positioned anterior to chaetae. Ventral cirri appears from chaetiger 7, fully developed on chaetiger 8– 9 (Fig 2, b). Two most posterior segments possesses emergent notopodial spines and neuroacicula, chaetae are absent, with considerably reduced parapodia lobes. Pygidium as an anal plate, 2 lateral anal cirri present, papillae­like, mid ventral anal cirrus not visible; ventral surface of pygidium plate has ‘m’ like groove (Fig 2, d); anus is positioned dorsally (Fig 2, c). Remarks: Loandalia fredrayorum differs from all other species of Loandalia by possessing the highest neurochaetae count, 20–24. L. fredrayorum differs from L. aberrans, L. gracilis, L. indica and L. ocularis by possessing uniramous parapodia only on chaetiger 1, rest biramous. Differs further from L. aberrans by the absence of dorsal cirri. L. fredrayorum differs from L. bennei, L. evelinae, L. riojai and L. gladstonensis sp. nov. by possessing singular palpostyles. Differing further from L. bennei, L. evelinae and L. gladstonensis by possessing notopodial spines emergent at chaetiger 9. L. fredrayorum differs from L. tricuspis and L. vivianneae by possessing ventral cirri starting at chaetiger 7 versus chaetiger 4; and notopodial spines starting at chaetiger 9 versus chaetiger 7. L. fredrayorum differs from L. americana, L. evelinae and L. maculata by possessing ventral cirri starting from chaetiger 7 versus chaetiger 6. Further differing from L. americana by possessing an emergent notopodial spine from chaetiger 9 versus chaetiger 2. L. fredrayorum differs further from L. fauveli by possessing a notopodial spine at chaetiger 9 versus chaetiger 8. L. fredrayorum differs further from L. maculata by possessing a notopodial spine at chaetiger 9 versus chaetiger 6. L. fredrayorum differs from L. salazarvallejoi by possessing anal cirri that are papillae­like versus elongate (longer than pygidium). Distinguishing features summarised in table 1.Published as part of Marks, Shona & Hocknull, Scott, 2006, New species of Loandalia (Polychaeta: Pilargidae) from Queensland, Australia, pp. 59-68 in Zootaxa 1119 on pages 62-63, DOI: 10.5281/zenodo.17168

Loandalia Monro

Genus Loandalia Monro Type Species: Loandalia aberrans Monro, 1936. Type number NHM 1936 ­ 2­8 ­ 3376. [Angola, Africa] Generic composition: L. americana Hartman (1947), [Gulf of Mexico]; L. bennei (Solís­Weiss 1983), [Mazatlan Bay, Mexico]; L. evelinae (León­González 1991), [Bahia of California]; L. fauveli Berkeley & Berkeley (1941), [Southern California]; L. fredrayorum sp. nov., [Moreton Bay, Australia]; L. gladstonensis sp. nov., [Gladstone Harbour, Australia]; L. gracilis Hartmann­Schröder (1959), [El Salvador]; L. indica Thomas (1963), [Arabian Sea]; L. maculata Intes & Le Loeuff (1975), [Ivory Coast]; L. ocularis Emerson & Fauchald (1971), [Santa Barbara, California]; L. riojai Salazar­Vallejo (1986), [Bahia of Manzanillo, Mexico]; L.salazarvallejoi León­González (1991), [Western Coast of Baja California, Mexico]; L. tricuspis Müller (1858), [Brazil]; L. vivianneae (Salazar­Vallejo & Reyes­Barragán 1990), [Eastern Mexico]. Diagnosis: Body cylindrical. Prostomium wider then long and reduced; biarticulated palps reduced. Median and lateral antennae absent; peristomial cirri absent. Jaws absent. Emergent notopodia spine present, straight; capillary notochaetae present, beside spine; notoacicula absent. Dorsal cirri absent (except L. aberrans). Ventral cirri present.Published as part of Marks, Shona & Hocknull, Scott, 2006, New species of Loandalia (Polychaeta: Pilargidae) from Queensland, Australia, pp. 59-68 in Zootaxa 1119 on page 61, DOI: 10.5281/zenodo.17168

Loandalia gladstonensis Marks & Hocknull, 2006, sp. nov.

Loandalia gladstonensis sp. nov. Fig 3, a–d. Etymology: Gladstone Harbour, type locality. Type Material: Holotype. QMC G 222948, Loandalia gladstonensis sp. nov. [Gladstone Harbour; station GH 144, S 23 ° 57 ’ 976 ”, E 151 ° 20 ’ 908 ”; depth 0–5m]. Paratypes. QMC G 222949, [Gladstone Harbour; station GH 148, S 23 ° 50 ’ 894 ”, E 151 ° 13 ’ 811 ”; intertidal]. QMC G 222950, [Gladstone Harbour; station GH038, S 23 ° 47 ’ 162 ”, E 151 ° 13 ’ 276 ”; intertidal]. QMC G 222951, [Gladstone Harbour; station GH 140, S 23 ° 51 ’ 170 ”, E 151 ° 18 ’ 892 ”; depth 0–5m]. QMC G 222952, [Gladstone Harbour; station GH016, S 23 ° 44 ’ 431 ”, E 151 °08’ 132 ”; intertidal]. QMC G 222953, [Gladstone Harbour, station GH014; S 23 ° 43 ’ 562 ”, E 151 ° 13 ’ 276 ”; depth 0–5m]. Habitat is intertidal or at depths of 0–5m, usually with sand or muddy substrates. Diagnosis: Bifid palpostyles; chaetigers 1–5 inflated; pharynx with distal ring of papillae (2 groups of 5); chaetiger 1 uniramous with remaining chaetigers biramous; single notochaeta present; straight emergent spine from chaetiger 7–8; ventral cirri present from chaetiger 5; 5–6 neurochaetae; posterior most segment possesses emergent notopodial spines and neuroacicula, with reduced parapodial lobes. Description: Pilargids of small size, length 30–62mm, with 79–114 chaetigers. Body of preserved individuals creamy/white to reddish/brown. Body slender with chaetiger 1–5 inflated; segmentation inconspicuous. Posterior segments slightly dorso­ventrally flattened. Prostomium discrete; palpophores divided; palpostyles papilla­like and bifid. Pharynx eversible with distal ring of 10 papillae, 5 dorsal and 5 ventral to pharyngeal slit; papillose band on pharynx, proximal to prostomium; pharyngeal slit vertical. Eye spots present, subdermal at chaetiger 1 (Fig 3, a). First parapodium uniramous with remaining chaetigers biramous; first neuropodia positioned dorsally compared to remaining chaetigers. Notopodial lobes fully developed by chaetiger 4; a single notochaetae present from chaetiger 2; notopodial spines emerging at chaetiger 7–8, increasing in length in posterior most 10 segments. Neuropodial lobe larger than notopodia, reduced in chaetiger 1–2; neurochaetae capillaries with numerous whorled teeth; 5–6 neurochaetae present per parapodia; emergent acicular from chaetiger 2. Ventral cirri from chaetiger 5 (Fig 3, b). Posterior most segment possesses emergent notopodial spines and neuroacicula, with considerably reduced parapodial lobes. Pygidium as an anal plate, dorsally concave with dorsal terminating anus, positioned at base of concave plate; 3 anal cirri present, papillaelike, 2 laterally and 1 mid ventrally positioned (Fig 3, c&d). Remarks: Loandalia gladstonensis differs from all species of Loandalia (except L. bennei, L. evelinae and L. riojai) by possessing bifid palpostyles. L. bennei, L. evelinae and L. riojai possess bifid palpostyles. L. gladstonensis further differs from L. gracilis and L. indica by possessing uniramous parapodia. L. gladstonensis differs from L. riojai, L. indica, L. ocularis, L. fauveli and L. americana by possessing a higher number of pharyngeal papillae (10). L. gladstonensis differs from L. evelinae, L. bennei and L. riojai by possessing a large rounded plate as the pygidium with papillae­like anal cirri. L. gladstonensis differs from L. evelinae, L. ocularis and L. vivianneae by the presence of emergent spines and neuroacicula on the last segment. L. gladstonensis differs from L. aberrans by lacking dorsal cirri. L. salazarvallejoi and L. fredrayorum differ from L. gladstonensis by possessing emergent notopodial spines starting at chaetiger 9 and 10 respectively; higher neurochaetae counts, 10–12 and 20–24 respectively. L. gladstonensis differs from L. maculata and L. tricuspis by possessing ventral cirri starting at chaetiger 5, versus chaetiger 4 in L. tricuspis and chaetiger 6 in L. maculata. Distinguishing features summarised in table 1.Published as part of Marks, Shona & Hocknull, Scott, 2006, New species of Loandalia (Polychaeta: Pilargidae) from Queensland, Australia, pp. 59-68 in Zootaxa 1119 on pages 65-66, DOI: 10.5281/zenodo.17168

Late Pleistocene-Holocene occurrence of Chaeropus (Peramelidae) and Macrotis (Thylacomyidae) from Queensland

Volume: 51Start Page: 38End Page: 3