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1.
Sci Rep ; 13(1): 14521, 2023 09 04.
Artículo en Inglés | MEDLINE | ID: mdl-37666885

RESUMEN

Diprotodontians are the morphologically and ecologically most diverse order of marsupials. However, an approximately 30-million-year gap in the Australian terrestrial vertebrate fossil record means that the first half of diprotodontian evolution is unknown. Fossil taxa from immediately either side of this gap are therefore critical for reconstructing the early evolution of the order. Here we report the likely oldest-known koala relatives (Phascolarctidae), from the late Oligocene Pwerte Marnte Marnte Local Fauna (central Australia). These include coeval species of Madakoala and Nimiokoala, as well as a new probable koala (?Phascolarctidae). The new taxon, Lumakoala blackae gen. et sp. nov., was comparable in size to the smallest-known phascolarctids, with body-mass estimates of 2.2-2.6 kg. Its bunoselenodont upper molars retain the primitive metatherian condition of a continuous centrocrista, and distinct stylar cusps B and D which lacked occlusion with the hypoconid. This structural arrangement: (1) suggests a morphocline within Phascolarctidae from bunoselenodonty to selenodonty; and (2) better clarifies the evolutionary transitions between molar morphologies within Vombatomorphia. We hypothesize that the molar form of Lumakoala blackae approximates the ancestral condition of the suborder Vombatiformes. Furthermore, it provides a plausible link between diprotodontians and the putative polydolopimorphians Chulpasia jimthorselli and Thylacotinga bartholomaii from the early Eocene Tingamarra Local Fauna (eastern Australia), which we infer as having molar morphologies consistent with stem diprotodontians.


Asunto(s)
Marsupiales , Phascolarctidae , Animales , Australia , Fósiles
2.
Anat Rec (Hoboken) ; 306(7): 1842-1863, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37314297

RESUMEN

The late Miocene Dromornis stirtoni is the largest of the giant flightless dromornithid birds. Here, we studied 22 long bones (femora, tibiotarsi, tarsometatarsi) of D. stirtoni to assess its osteohistology to deduce various aspects of its life history. Our results show that D. stirtoni took several years (likely, more than a decade), to reach adult body size, after which its growth rate slowed down, and skeletal maturity occurred. This growth strategy differs from that of its Pleistocene relative, Genyornis newtoni, which experienced faster rates of growth to reach adult body size. We propose that these mihirung birds, separated by millions of years, each responded to the prevailing environmental conditions of the time, by selecting for different growth strategies, with D. stirtoni having an extreme K-selected life history strategy. The presence of medullary bone permitted the identification of female D. stirtoni specimens, and its presence in some bones lacking an OCL layer showed sexual maturity preceded its formation. We postulate that while G. newtoni had a somewhat greater reproductive potential than D. stirtoni, it remained far less than that observed in the extant emu (Dromaius novaehollandiae). Genyornis newtoni survived into the late Pleistocene alongside extant emus and overlapped the arrival of the first humans in Australia, but the former species shortly thereafter became extinct while emus remain prolific.


Asunto(s)
Huesos , Dromaiidae , Animales , Femenino , Australia
3.
R Soc Open Sci ; 10(5): 230211, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37266037

RESUMEN

Diprotodontids were the largest marsupials to exist and an integral part of Australian terrestrial ecosystems until the last members of the group became extinct approximately 40 000 years ago. Despite the frequency with which diprotodontid remains are encountered, key aspects of their morphology, systematics, ecology and evolutionary history remain poorly understood. Here we describe new skeletal remains of the Pliocene taxon Zygomaturus keanei from northern South Australia. This is only the third partial skeleton of a late Cenozoic diprotodontid described in the last century, and the first displaying soft tissue structures associated with footpad impressions. Whereas it is difficult to distinguish Z. keanei and the type species of the genus, Z. trilobus, on dental grounds, the marked cranial and postcranial differences suggest that Z. keanei warrants genus-level distinction. Accordingly, we place it in the monotypic Ambulator gen. nov. We, also recognize the late Miocene Z. gilli as a nomen dubium. Features of the forelimb, manus and pes reveal that Ambulator keanei was more graviportal with greater adaptation to quadrupedal walking than earlier diprotodontids. These adaptations may have been driven by a need to travel longer distances to obtain resources as open habitats expanded in the late Pliocene of inland Australia.

4.
Zootaxa ; 5168(1): 39-50, 2022 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-36101302

RESUMEN

A large fossil anserine-like anatid (Aves, Anatidae, Notochen bannockburnensis gen. et sp. nov.) is described based on a distal humerus from the lower Bannockburn Formation, early Miocene (1916 Ma), St Bathans Fauna from New Zealand. Its morphology and size suggest that this taxon represents an early swan rather than a goose. Extant anserines are split into Northern and Southern Hemisphere clades. The St Bathans Fauna is known to have the oldest anserines in the Southern Hemisphere, unnamed cereopsines perhaps ancestral to species of Cnemiornis (New Zealand geese). The elongate and flat morphology of the tuberculum supracondylare ventrale of the new species, however, preclude affinities with cereopsines. It is a rare taxon and the eighth anatid represented in the fauna and is the largest known anseriform from the Oligo-Miocene of Australasia. We also reassess other large anatid specimens from the St Bathans Fauna and identify Miotadorna catrionae Tennyson, Greer, Lubbe, Marx, Richards, Giovanardi Rawlence, 2022 as a junior synonym of Miotadorna sanctibathansi Worthy, Tennyson, Jones, McNamara Douglas, 2007.


Asunto(s)
Anseriformes , Fósiles , Animales , Aves/anatomía & histología , Nueva Zelanda , Filogenia
5.
Zootaxa ; 5168(1): 1-23, 2022 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-36101304

RESUMEN

The Australian Pleistocene fossil record of the Accipitridae (hawks, eagles and Old World vultures) is sparse and poorly known. Only two extinct confirmed accipitrid species have been described for this time period; both have received little investigation since their description. One is Taphaetus lacertosus de Vis, 1905, described from a distal humerus and a quadrate from north-eastern South Australia. While this species was verified as an accipitrid in subsequent studies, its more precise taxonomic affinities have remained conjectural. In this study, a new analysis incorporating newly referred material and phylogenetic analyses using a wide range of accipitriforms reveals that the lectotype humerus of T. lacertosus is an Old World vulture in the subfamily Aegypiinae. The associated quadrate, one of two original syntypes from which de Vis named this species, is of an indeterminate species of ardeid. We erect the novel genus Cryptogyps, to accommodate the species lacertosus, as it cannot be placed in Taphaetus de Vis, 1891, because the type species of this genus, Uroaetus brachialis de Vis, 1889, was transferred back to the genus Uroaetus, a synonym of Aquila Brisson, by de Vis in 1905. Further, U. brachialis is now considered a synonym of Aquila audax (Latham, 1801). Moreover, Taphaetus de Vis, 1891 is a senior homonym of Taphaetus de Vis, 1905, type species Taphaetus lacertosus de Vis, 1905, making the 1905 version of the genus unavailable. Newly referred fossils from Wellington Caves (NSW) and the Nullarbor Plains (WA) reveal this taxon had a wide geographical range across Pleistocene Australia. The referred tarsometatarsus lacks hyper-developed trochleae, indicating that Cryptogyps lacertosus (de Vis, 1905) comb. nov., was probably a scavenger like other aegypiines. Identification of Cryptogyps lacertosus as an aegypiine significantly expands the palaeogeographical range of the Old World vultures, hitherto unknown in Australia. The avian guild of large, obligate scavenging birds of prey, is currently absent in the modern Australian biota, but its former presence is not surprising given the megafauna-rich communities of the Pleistocene.


Asunto(s)
Águilas , Rapaces , Animales , Australia , Fósiles , Filogenia
6.
R Soc Open Sci ; 9(5): 220135, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35620001

RESUMEN

Nocturnal birds display diverse adaptations of the visual system to low-light conditions. The skulls of birds reflect many of these and are used increasingly to infer nocturnality in extinct species. However, it is unclear how reliable such assessments are, particularly in cases of recent evolutionary transitions to nocturnality. Here, we investigate a case of recently evolved nocturnality in the world's only nocturnal hawk, the letter-winged kite Elanus scriptus. We employed phylogenetically informed analyses of orbit, optic foramen and endocast measurements from three-dimensional reconstructions of micro-computed tomography scanned skulls of the letter-winged kite, two congeners, and 13 other accipitrid and falconid raptors. Contrary to earlier suggestions, the letter-winged kite was not unique in any of our metrics. However, all species of Elanus have significantly higher ratios of orbit versus optic foramen diameter, suggesting high visual sensitivity at the expense of acuity. In addition, visual system morphology varies greatly across accipitrid species, likely reflecting hunting styles. Overall, our results suggest that the transition to nocturnality can occur rapidly and without changes to key hard-tissue indicators of vision, but also that hard-tissue anatomy of the visual system may provide a means of inferring a range of raptor behaviours, well beyond nocturnality.

8.
BMC Evol Biol ; 19(1): 233, 2019 12 27.
Artículo en Inglés | MEDLINE | ID: mdl-31881941

RESUMEN

BACKGROUND: Palaeognathae is a basal clade within Aves and include the large and flightless ratites and the smaller, volant tinamous. Although much research has been conducted on various aspects of palaeognath morphology, ecology, and evolutionary history, there are still areas which require investigation. This study aimed to fill gaps in our knowledge of the Southern Cassowary, Casuarius casuarius, for which information on the skeletal systems of the syrinx, hyoid and larynx is lacking - despite these structures having been recognised as performing key functional roles associated with vocalisation, respiration and feeding. Previous research into the syrinx and hyoid have also indicated these structures to be valuable for determining evolutionary relationships among neognath taxa, and thus suggest they would also be informative for palaeognath phylogenetic analyses, which still exhibits strong conflict between morphological and molecular trees. RESULTS: The morphology of the syrinx, hyoid and larynx of C. casuarius is described from CT scans. The syrinx is of the simple tracheo-bronchial syrinx type, lacking specialised elements such as the pessulus; the hyoid is relatively short with longer ceratobranchials compared to epibranchials; and the larynx is comprised of entirely cartilaginous, standard avian anatomical elements including a concave, basin-like cricoid and fused cricoid wings. As in the larynx, both the syrinx and hyoid lack ossification and all three structures were most similar to Dromaius. We documented substantial variation across palaeognaths in the skeletal character states of the syrinx, hyoid, and larynx, using both the literature and novel observations (e.g. of C. casuarius). Notably, new synapomorphies linking Dinornithiformes and Tinamidae are identified, consistent with the molecular evidence for this clade. These shared morphological character traits include the ossification of the cricoid and arytenoid cartilages, and an additional cranial character, the articulation between the maxillary process of the nasal and the maxilla. CONCLUSION: Syrinx, hyoid and larynx characters of palaeognaths display greater concordance with molecular trees than do other morphological traits. These structures might therefore be less prone to homoplasy related to flightlessness and gigantism, compared to typical morphological traits emphasised in previous phylogenetic studies.


Asunto(s)
Laringe/anatomía & histología , Paleognatos/anatomía & histología , Paleognatos/genética , Filogenia , Animales , Evolución Biológica , Femenino , Glotis/anatomía & histología , Masculino , Orofaringe/anatomía & histología , Paleognatos/clasificación , Vocalización Animal
9.
Biol Lett ; 15(8): 20190467, 2019 08 30.
Artículo en Inglés | MEDLINE | ID: mdl-31387471

RESUMEN

Insular avifaunas have repeatedly spawned evolutionary novelties in the form of unusually large, often flightless species. We report fossils from the Early Miocene St Bathans Fauna of New Zealand that attests to the former existence of a giant psittaciform, which is described as a new genus and species. The fossils are two incomplete tibiotarsi from a bird with an estimated mass of 7 kg, double that of the heaviest known parrot, the kakapo Strigops habroptila. These psittaciform fossils show that parrots join the growing group of avian taxa prone to giantism in insular species, currently restricted to palaeognaths, anatids, sylviornithids, columbids, aptornithids, ciconiids, tytonids, falconids and accipitrids.


Asunto(s)
Loros , Animales , Evolución Biológica , Fósiles , Nueva Zelanda , Filogenia
10.
Sci Rep ; 8(1): 235, 2018 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-29321543

RESUMEN

A new genus and species of fossil bat is described from New Zealand's only pre-Pleistocene Cenozoic terrestrial fauna, the early Miocene St Bathans Fauna of Central Otago, South Island. Bayesian total evidence phylogenetic analysis places this new Southern Hemisphere taxon among the burrowing bats (mystacinids) of New Zealand and Australia, although its lower dentition also resembles Africa's endemic sucker-footed bats (myzopodids). As the first new bat genus to be added to New Zealand's fauna in more than 150 years, it provides new insight into the original diversity of chiropterans in Australasia. It also underscores the significant decline in morphological diversity that has taken place in the highly distinctive, semi-terrestrial bat family Mystacinidae since the Miocene. This bat was relatively large, with an estimated body mass of ~40 g, and its dentition suggests it had an omnivorous diet. Its striking dental autapomorphies, including development of a large hypocone, signal a shift of diet compared with other mystacinids, and may provide evidence of an adaptive radiation in feeding strategy in this group of noctilionoid bats.


Asunto(s)
Biodiversidad , Quirópteros/anatomía & histología , Fósiles , Animales , Teorema de Bayes , Evolución Biológica , Quirópteros/clasificación , Quirópteros/genética , Ecología , Nueva Zelanda , Fenotipo , Filogenia
11.
R Soc Open Sci ; 4(10): 170975, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29134094

RESUMEN

The extinct dromornithids, gastornithids and phorusrhacids are among the most spectacular birds to have ever lived, with some giants exceeding 500 kg. The affinities and evolution of these and other related extinct birds remain contentious, with previous phylogenetic analyses being affected by widespread convergence and limited taxon sampling. We address these problems using both parsimony and tip-dated Bayesian approaches on an expansive taxon set that includes all key extinct flightless and flighted (e.g. Vegavis and lithornithids) forms, an extensive array of extant fowl (Galloanseres), representative Neoaves and palaeognaths. The Paleogene volant Lithornithidae are recovered as stem palaeognaths in the Bayesian analyses. The Galloanseres comprise four clades inferred to have diverged in the Late Cretaceous on Gondwana. In addition to Anseriformes and Galliformes, we recognize a robust new clade (Gastornithiformes) for the giant flightless Dromornithidae (Australia) and Gastornithidae (Eurasia, North America). This clade exhibits parallels to ratite palaeognaths in that flight presumably was lost and giant size attained multiple times. A fourth clade is represented by the Cretaceous Vegavis (Antarctica), which was strongly excluded from Anseriformes; thus, a crucial molecular calibration point needs to be reconsidered. The presbyornithids Wilaru (Australia) and Presbyornis (Northern Hemisphere) are robustly found to be the sister group to Anatoidea (Anseranatidae + Anatidae), a relatively more basal position than hitherto recognized. South America's largest bird, Brontornis, is not a galloansere, but a member of Neoaves related to Cariamiformes; therefore, giant Galloanseres remain unknown from this continent. Trait analyses showed that while gigantism and flightlessness evolved repeatedly in groups, diet is constrained by phylogeny: all giant Galloanseres and palaeognaths are herbivores or mainly herbivorous, and giant neoavians are zoophagous or omnivorous.

12.
R Soc Open Sci ; 4(6): 170233, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28680676

RESUMEN

Megapodes are unusual galliform birds that use passive heat sources to incubate their eggs. Evolutionary relationships of extant megapode taxa have become clearer with the advent of molecular analyses, but the systematics of large, extinct forms (Progura gallinacea, Progura naracoortensis) from the late Cenozoic of Australia has been a source of confusion. It was recently suggested that the two species of Progura were synonymous, and that this taxon dwarfed into the extant malleefowl Leipoa ocellata in the Late Pleistocene. Here, we review previously described fossils along with newly discovered material from several localities, and present a substantial taxonomic revision. We show that P. gallinacea and P. naracoortensis are generically distinct, describe two new species of megapode from the Thylacoleo Caves of south-central Australia, and a new genus from Curramulka Quarry in southern Australia. We also show that L. ocellata was contemporaneous with larger species. Our phylogenetic analysis places four extinct taxa in a derived clade with the extant Australo-Papuan brush-turkeys Talegalla fuscirostris, L. ocellata, Alectura lathami and Aepypodius bruijnii. Therefore, diversity of brush-turkeys halved during the Quaternary, matching extinction rates of scrubfowl in the Pacific. Unlike extant brush-turkeys, all the extinct taxa appear to have been burrow-nesters.

13.
R Soc Open Sci ; 4(11): 171621, 2017 11.
Artículo en Inglés | MEDLINE | ID: mdl-29292801

RESUMEN

[This corrects the article DOI: 10.1098/rsos.170975.].

14.
Sci Rep ; 6: 38317, 2016 12 06.
Artículo en Inglés | MEDLINE | ID: mdl-27922064

RESUMEN

We report the unprecedented Lapita exploitation and subsequent extinction of large megafauna tortoises (?Meiolania damelipi) on tropical islands during the late Holocene over a 281,000 km2 region of the southwest Pacific spanning from the Vanuatu archipelago to Viti Levu in Fiji. Zooarchaeological analyses have identified seven early archaeological sites with the remains of this distinctive hornless tortoise, unlike the Gondwanan horned meiolaniid radiation to the southwest. These large tortoise radiations in the Pacific may have contributed to the rapid dispersal of early mobile Neolithic hunters throughout southwest Melanesia and on to western Polynesia. Subsequent rapid extinctions of these terrestrial herbivorous megafauna are likely to have led to significant changes in ecosystems that help explain changes in current archaeological patterns from Post-Lapita contexts in the region.


Asunto(s)
Dieta Paleolítica/historia , Extinción Biológica , Fósiles/historia , Nativos de Hawái y Otras Islas del Pacífico/historia , Tortugas/fisiología , Distribución Animal/fisiología , Animales , Arqueología , Fósiles/anatomía & histología , Historia Antigua , Humanos , Islas del Pacífico , Tortugas/anatomía & histología
15.
Nature ; 539(7628): 280-283, 2016 11 10.
Artículo en Inglés | MEDLINE | ID: mdl-27806378

RESUMEN

Elucidating the material culture of early people in arid Australia and the nature of their environmental interactions is essential for understanding the adaptability of populations and the potential causes of megafaunal extinctions 50-40 thousand years ago (ka). Humans colonized the continent by 50 ka, but an apparent lack of cultural innovations compared to people in Europe and Africa has been deemed a barrier to early settlement in the extensive arid zone. Here we present evidence from Warratyi rock shelter in the southern interior that shows that humans occupied arid Australia by around 49 ka, 10 thousand years (kyr) earlier than previously reported. The site preserves the only reliably dated, stratified evidence of extinct Australian megafauna, including the giant marsupial Diprotodon optatum, alongside artefacts more than 46 kyr old. We also report on the earliest-known use of ochre in Australia and Southeast Asia (at or before 49-46 ka), gypsum pigment (40-33 ka), bone tools (40-38 ka), hafted tools (38-35 ka), and backed artefacts (30-24 ka), each up to 10 kyr older than any other known occurrence. Thus, our evidence shows that people not only settled in the arid interior within a few millennia of entering the continent, but also developed key technologies much earlier than previously recorded for Australia and Southeast Asia.


Asunto(s)
Evolución Cultural/historia , Clima Desértico , Extinción Biológica , Migración Humana/historia , Tecnología/historia , Animales , Arqueología , Asia Sudoriental , Australia , Aves , Colorantes/historia , Historia Antigua , Humanos , Marsupiales
16.
Mol Phylogenet Evol ; 102: 295-304, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27261250

RESUMEN

The New Zealand acanthisittid wrens are the sister-taxon to all other "perching birds" (Passeriformes) and - including recently extinct species - represent the most diverse endemic passerine family in New Zealand. Consequently, they are important for understanding both the early evolution of Passeriformes and the New Zealand biota. However, five of the seven species have become extinct since the arrival of humans in New Zealand, complicating evolutionary analyses. The results of morphological analyses have been largely equivocal, and no comprehensive genetic analysis of Acanthisittidae has been undertaken. We present novel mitochondrial genome sequences from four acanthisittid species (three extinct, one extant), allowing us to resolve the phylogeny and revise the taxonomy of acanthisittids. Reanalysis of morphological data in light of our genetic results confirms a close relationship between the extant rifleman (Acanthisitta chloris) and an extinct Miocene wren (Kuiornis indicator), making Kuiornis a useful calibration point for molecular dating of passerines. Our molecular dating analyses reveal that the stout-legged wrens (Pachyplichas) diverged relatively recently from a more gracile (Xenicus-like) ancestor. Further, our results suggest a possible Early Oligocene origin of the basal Lyall's wren (Traversia) lineage, which would imply that Acanthisittidae survived the Oligocene marine inundation of New Zealand and therefore that the inundation was not complete.


Asunto(s)
Genoma Mitocondrial , Pájaros Cantores/clasificación , Animales , Teorema de Bayes , Evolución Biológica , Huesos/metabolismo , ADN/química , ADN/aislamiento & purificación , ADN/metabolismo , ADN Mitocondrial/química , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , Extinción Biológica , Nueva Zelanda , Filogenia , Análisis de Secuencia de ADN , Pájaros Cantores/genética
17.
PLoS One ; 11(3): e0150871, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27027304

RESUMEN

The giant flightless bird Sylviornis neocaledoniae (Aves: Sylviornithidae) existed on La Grande Terre and Ile des Pins, New Caledonia, until the late Holocene when it went extinct shortly after human arrival on these islands. The species was generally considered to be a megapode (Megapodiidae) until the family Sylviornithidae was erected for it in 2005 to reflect multiple cranial autapomorphies. However, despite thousands of bones having been reported for this unique and enigmatic taxon, the postcranial anatomy has remained largely unknown. We rectify this deficiency and describe the postcranial skeleton of S. neocaledoniae based on ~600 fossils and use data from this and its cranial anatomy to make a comprehensive assessment of its phylogenetic affinities. Sylviornis neocaledoniae is found to be a stem galliform, distant from megapodiids, and the sister taxon to the extinct flightless Megavitiornis altirostris from Fiji, which we transfer to the family Sylviornithidae. These two species form the sister group to extant crown-group galliforms. Several other fossil galloanseres also included in the phylogenetic analysis reveal novel hypotheses of their relationships as follows: Dromornis planei (Dromornithidae) is recovered as a stem galliform rather than a stem anseriform; Presbyornis pervetus (Presbyornithidae) is the sister group to Anseranatidae, not to Anatidae; Vegavis iaai is a crown anseriform but remains unresolved relative to Presbyornis pervetus, Anseranatidae and Anatidae. Sylviornis neocaledoniae was reconstructed herein to be 0.8 m tall in a resting stance and weigh 27-34 kg. The postcranial anatomy of S. neocaledoniae shows no indication of the specialised adaptation to digging seen in megapodiids, with for example, its ungual morphology differing little from that of chicken Gallus gallus. These observations and its phylogenetic placement as stem galliforms makes it improbable that this species employed ectothermic incubation or was a mound-builder. Sylviornis neocaledoniae can therefore be excluded as the constructor of tumuli in New Caledonia.


Asunto(s)
Aves/clasificación , Animales , Aves/anatomía & histología , Vértebras Cervicales/anatomía & histología , Extinción Biológica , Fémur/anatomía & histología , Pie/anatomía & histología , Fósiles , Nueva Zelanda , Pelvis/anatomía & histología , Filogenia , Tarso Animal/anatomía & histología
18.
R Soc Open Sci ; 3(2): 150635, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26998335

RESUMEN

Presbyornithids were the dominant birds in Palaeogene lacustrine assemblages, especially in the Northern Hemisphere, but are thought to have disappeared worldwide by the mid-Eocene. Now classified within Anseriformes (screamers, ducks, swans and geese), their relationships have long been obscured by their strange wader-like skeletal morphology. Reassessment of the late Oligocene South Australian material attributed to Wilaru tedfordi, long considered to be of a stone-curlew (Burhinidae, Charadriiformes), reveals that this taxon represents the first record of a presbyornithid in Australia. We also describe the larger Wilaru prideauxi sp. nov. from the early Miocene of South Australia, showing that presbyornithids survived in Australia at least until ca 22 Ma. Unlike on other continents, where presbyornithids were replaced by aquatic crown-group anatids (ducks, swans and geese), species of Wilaru lived alongside these waterfowl in Australia. The morphology of the tarsometatarsus of these species indicates that, contrary to other presbyornithids, they were predominantly terrestrial birds, which probably contributed to their long-term survival in Australia. The morphological similarity between species of Wilaru and the Eocene South American presbyornithid Telmabates antiquus supports our hypothesis of a Gondwanan radiation during the evolutionary history of the Presbyornithidae. Teviornis gobiensis from the Late Cretaceous of Mongolia is here also reassessed and confirmed as a presbyornithid. These findings underscore the temporal continuance of Australia's vertebrates and provide a new context in which the phylogeny and evolutionary history of presbyornithids can be examined.

19.
Proc Biol Sci ; 283(1822)2016 01 13.
Artículo en Inglés | MEDLINE | ID: mdl-26763698

RESUMEN

The moa (Dinornithiformes) are large to gigantic extinct terrestrial birds of New Zealand. Knowledge about niche partitioning, feeding mode and preference among moa species is limited, hampering palaeoecological reconstruction and evaluation of the impacts of their extinction on remnant native biota, or the viability of exotic species as proposed ecological 'surrogates'. Here we apply three-dimensional finite-element analysis to compare the biomechanical performance of skulls from five of the six moa genera, and two extant ratites, to predict the range of moa feeding behaviours relative to each other and to living relatives. Mechanical performance during biting was compared using simulations of the birds clipping twigs based on muscle reconstruction of mummified moa remains. Other simulated food acquisition strategies included lateral shaking, pullback and dorsoventral movement of the skull. We found evidence for limited overlap in biomechanical performance between the extant emu (Dromaius novaehollandiae) and extinct upland moa (Megalapteryx didinus) based on similarities in mandibular stress distribution in two loading cases, but overall our findings suggest that moa species exploited their habitats in different ways, relative to both each other and extant ratites. The broad range of feeding strategies used by moa, as inferred from interspecific differences in biomechanical performance of the skull, provides insight into mechanisms that facilitated high diversities of these avian herbivores in prehistoric New Zealand.


Asunto(s)
Aves/fisiología , Herbivoria , Cráneo/fisiología , Animales , Fenómenos Biomecánicos , Extinción Biológica , Fósiles , Imagenología Tridimensional , Nueva Zelanda , Cráneo/anatomía & histología , Especificidad de la Especie
20.
PLoS One ; 10(6): e0128871, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26083758

RESUMEN

The New Zealand endemic bat family Mystacinidae comprises just two Recent species referred to a single genus, Mystacina. The family was once more diverse and widespread, with an additional six extinct taxa recorded from Australia and New Zealand. Here, a new mystacinid is described from the early Miocene (19-16 Ma) St Bathans Fauna of Central Otago, South Island, New Zealand. It is the first pre-Pleistocene record of the modern genus and it extends the evolutionary history of Mystacina back at least 16 million years. Extant Mystacina species occupy old-growth rainforest and are semi-terrestrial with an exceptionally broad omnivorous diet. The majority of the plants inhabited, pollinated, dispersed or eaten by modern Mystacina were well-established in southern New Zealand in the early Miocene, based on the fossil record from sites at or near where the bat fossils are found. Similarly, many of the arthropod prey of living Mystacina are recorded as fossils in the same area. Although none of the Miocene plant and arthropod species is extant, most are closely related to modern taxa, demonstrating potentially long-standing ecological associations with Mystacina.


Asunto(s)
Evolución Biológica , Quirópteros/fisiología , Dieta , Fósiles , Filogenia , Animales , Quirópteros/anatomía & histología , Quirópteros/clasificación , Ecosistema , Cadena Alimentaria , Nueva Zelanda , Plantas , Bosque Lluvioso
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