2019 SVP Annual Meeting Program and Abstracts (1 Viewer)

[Fred Ruhe]

SOCIETY OF VERTEBRATE PALEONTOLOGY OCTOBER 2019
ASBTRACTS OF PAPERS
79TH ANNUAL MEETING
Brisbane Convention and Exhibition Centre
Brisbane, Queensland, Australia
October 9-12, 2019

http://vertpaleo.org/Annual-Meeting...am-book-v5_w-covers.aspx?vsmaid=573&vcid=5063

Bird relates program:

WEDNESDAY AFTERNOON, OCTOBER 9, 2019
TECHNICAL SESSION V: CENOZOIC BIRDS
MEETING ROOM M4
MODERATORS: Thomas Stidham and Anusuya Chinsamy-Turan

A. Chinsamy-Turan, T. H. Worthy, W. D. Handley GROWTH STRATEGIES LINKED TO PREVAILING ENVIRONMENTAL CONDITIONS IN AUSTRALIAN GIANT FLIGHTLESS MIHIRUNG BIRDS (AVES: DROMORNITHIDAE)
The dromornithids were giant flightless birds endemic to Australia. They are
known from the late Paleogene to the late Pleistocene and are represented by eight species in four genera. Here we focus on the largest known dromornithid, and among the heaviest birds (about 610 Kg), the late Miocene aged Dromornis stirtoni; and the medium sized Genyornis newtoni that probably weighed about 250 Kg. Genyornis is the youngest member of the dromornithids and became extinct about 40 000 years ago. Since little is known about the biology of these birds, we undertook a histological investigation of their bones to deduce various aspects of their life history. This study focuses on four tibiotarsi, two tarsometatarsi and a femur of Genyornis that were recovered from the northern desert regions of South Australia. In addition, we expanded our previous osteohistology sample by including additional younger and adult specimens of Dromornis from the late Miocene Alcoota Local Fauna in the Northern Territory of Australia. The bone histology of Dromornis and Genyornis show that these birds experienced a cyclical pattern of growth with alternating rapid and slower rates of osteogenesis. During faster periods of growth they deposited fibrolamellar bone tissue, whilst during periods of slowed growth they formed lamellar bone tissue, which was sometimes associated with lines of arrested growth indicating pauses in osteogenesis and growth. However, we found that these birds differed in the amount of time taken to grow to maturity: Dromornis has over 10 growth cycles while Genyornis shows a maximum of 3 growth cycles. Interestingly, in Genyornis some of the lamellar deposits are wide, indicating that they grew slowly for longer periods of time. The main aridification of Australia is considered to have occurred from the Late Miocene through to the Pleistocene. We postulate that the growth dynamics of the dromornithids were adapted to the particular environment in which they lived, i.e., Dromornis lived before the main aridification and therefore a k-selected lifestyle strategy would have been advantageous. However, as landscape resources became less predictable, then r-selected strategies were favoured by Genyornis. The wide bands of lamellar bone in some of the Genyornis samples may be coincident with lengthy stressful periods (drought).

 

[Fred Ruhe]

A. Chen, N. D. White, R. Benson, M. J. Braun, D. Field TOTAL-EVIDENCE FRAMEWORK REVEALS COMPLEX MORPHOLOGICAL EVOLUTION AND RAPID EVOLUTION IN NIGHTBIRDS (STRISORES)
Strisores is a clade of often insectivorous neoavian birds that includes specialized fliers such as swifts and hummingbirds, as well as a large diversity of nocturnal species such as nightjars. Despite the use of large-scale molecular datasets, the precise phylogenetic relationships among major strisorean groups remain controversial. Given the lack of consensus among recent phylogenomic datasets, we incorporated anatomical data from living and fossil strisoreans into a Bayesian total-evidence framework. This combined analysis of molecular and morphological data resulted in a phylogenetic topology for Strisores that is congruent with the findings of a recent molecular phylogenomic study of modern birds. However, we found that integration of molecular and morphological data did not yield increased statistical confidence in our topology, highlighting apparent homoplasy in both sequence and anatomical data. We suggest that disparate strisorean lineages
have experienced convergent evolution across the skeleton, and that many of the distinctive specializations of strisorean subclades were acquired early in their evolutionary history. Furthermore, the results of applying tip-dating methods to this dataset indicate very rapid diversification of major strisorean lineages shortly following the origin of this clade. These complex patterns have resulted in a challenging phylogenetic problem, which obfuscates the robust inference of ancestral character states.

Alxo see: https://www.birdforum.net/showthread.php?t=380349

 

[Fred Ruhe]

D. J. Field, E. E. Saupe CLIMATIC SHIFTS DROVE MAJOR CONTRACTIONS IN AVIAN LATITUDINAL DISTRIBUTIONS THROUGHOUT THE CENOZOIC
Numerous higher-level avian clades are restricted to Earth’s lower latitudes, leading to historical biogeographic reconstructions favoring a Gondwanan origin of crown birds and many deep subclades. However, such ‘tropicalrestricted’ clades are frequently represented by stem-lineage fossils well outside the ranges of their closest living relatives, often on northern continents. To assess the drivers of these geographic disjunctions, we combined ecological niche modeling, paleoclimate models, and the early Cenozoic fossil record to examine the influence of climatic change on avian geographic distributions over the last ~56 million years. By modeling the distribution of suitable habitable area through time, we illustrate that most high latitude Paleogene fossil-bearing localities would have been suitable for occupancy by present-day 'tropical' clade representatives when the fossils were deposited. Potentially-suitable habitat for numerous higher-level clades is inferred to have become progressively restricted towards the tropics throughout the Cenozoic, culminating in relatively narrow circumtropical distributions in the present day. This pattern manifests in a pronounced sharpening of the avian latitudinal diversity gradient through the Paleogene and Neogene. Our results support coarse-scale niche conservatism at the clade level, and are consistent with a scenario whereby climate change over geological timescales has largely dictated the geographic distributions of major avian clades. The distinctive modern bias towards high avian diversity at tropical latitudes for most hierarchical taxonomic levels may therefore represent a relatively recent phenomenon, overprinting a complex biogeographic history characterized by dramatic geographic range shifts driven by Earth’s changing climate and intercontinental dispersal. Earth’s current climatic trajectory portends a return to a megathermal state, which may dramatically influence the geographic distributions of many range-restricted extant clades.

 

[Fred Ruhe]

P. Scofield, V. De Pietri, A. Mannering, L. Love, G. Mayr MEDICAL CT REVEALS THE OLDEST, SMALLEST, AND PHYLOGENETICALLY MOST BASAL PELAGORNITHID (AVES: ODONTOPTERYGIFORMES), FROM THE EARLY PALEOCENE OF NEW ZEALAND
Although huge advances have been made in the last 20 years in the use of computed tomography (CT) in paleontology, the majority of recent studies use specialist micro-micro-􀀦􀀷􀀃 􀀋􀈝􀀦􀀷􀀌􀀃 􀁈􀁆􀁋􀁑􀁒􀁏􀁒􀁊􀁜􀀑 Here we show how the use of advanced medical CT using dual energy can (in some cases) allow the 􀁕􀁄􀁆􀁗􀁈􀁕􀁌􀁖􀁄􀁗􀁌􀁒􀁑􀀃􀁄􀁑􀁇􀀃􀁇􀁈􀁖􀁆􀁕􀁌􀁓􀁗􀁌􀁒􀁑􀀃􀁒􀁉􀀃􀁉􀁒􀁖􀁖􀁌􀁏􀁖􀀃􀁅􀁈􀁗􀁗􀁈􀁕􀀃􀁗􀁋􀁄􀁑􀀃􀁘􀁖􀁌􀁑􀁊􀀃􀁖􀁓􀁈􀁆􀁌􀁄􀁏􀁌􀁖􀁗􀀃 this study we scanned and segmented a partial skeleton of a small-sized pelagornithid bird from the early Paleocene of New Zealand. The new taxon investigated was in a pyrite-rich glauconitic greensand that did not allow 􀁘􀁆􀁆􀁈􀁖􀁖􀁉􀁘􀁏􀀃 􀁌􀁐􀁄􀁊􀁌􀁑􀁊􀀃 􀁘􀁖􀁌􀁑􀁊􀀃 􀈝􀀦􀀷􀀑􀀃 􀀥􀁜􀀃 􀁘􀁖􀁌􀁑􀁊􀀃 􀁄􀀃 􀁈􀁇􀁌􀁆􀁄􀁏􀀃 􀀶􀁌􀁈􀁐􀁈􀁑􀁖􀀃 􀀧􀁘􀁄􀁏􀀃 Energy CTSOMATOM Definition scanner a high quality scan free of metallic x-ray artefacts was produced. Thus we were able to describe and characterise the oldest record of the Pelagornithidae globally, the smallest known species, and the first pre-Eocene pelagornithid from the Southern Hemisphere. The skull of the new species exhibits the characteristic pelagornithid morphology, but the postcranial skeleton distinctly differs from other pelagornithids and various plesiomorphic features indicate that it is the earliest-diverging representative of the Pelagornithidae. The much stouter humerus suggests that the new species was less adapted to sustained soaring than previously known pelagornithids. Pseudoteeth therefore evolved before pelagornithids became highly specialized gliders. The new species furthermore suggests that pelagornithids evolved in the Southern Hemisphere and documents a very early radiation of neornithine seabirds, which may have been triggered by changes in marine ecosystems at the end of the Mesozoic.

 

[Fred Ruhe]

R. D. Marek THE SURROGATE ARM: FUNCTIONAL AND ECOLOGICAL DRIVERS OF NECK MORPHOLOGY IN EXTANT AVES
With the forelimbs primarily adapted for flight, the avian neck allows the head to perform a variety of tasks that would be carried out by the grasping hands of their dinosaur antecedents. This has created a strong additional selection pressure on the cervical column and has resulted in the evolution of a vast array of neck morphologies in extant birds. However, no quantitative assessment of this variation has been undertaken and as such there is little understanding of how the neck evolved to become such an important component of avian biology. Here I use a holistic approach to understand functional and ecological drivers in avian neck shape and length in a diverse selection (46 species) of modern birds by combining three-dimensiona geometric morphometrics with multivariate statistics and quantitative dissection. I analysed the effects of ecology on the overall morphology of the avian cervical column by comparing cervical shape trajectories of a number of ecological groups (diet and locomotor mode) using Phenotypic Trajectory Analysis. Procrustes Distance phylogenetic Generalised Least-Squares models were used to assess the impact of ecological and functional factors (neck length, body mass and head mass) on the morphology of specific cervical regions. Results show that functional, not ecological, factors (particularly body mass and neck length) correlate with much of the variation in cervical morphology in different regions of the cervical column. Specialised species with ecologies that require radically different cervical motions (such as carnivores and piscivores) are the only ecological groups to show significant variation in cervical shape. Quantitative dissection reveals the muscles of these specialised groups have significantly different properties to other birds and these properties are linked to morphological variation in the vertebrae they attach to. Therefore, despite the appearance of abundant variability, the morphology of avian cervical column is actually highly generalised and only varies when specific cervical motions are required, such as for the tearing of flesh from prey in carnivorous taxa. The functional signal seen in both osteological and soft-tissue data instils confidence in future work that will investigate the evolution of the neck of dinosaurs and track the role of the cervical column as forelimbs adapt for flight in early birds.

 

[Fred Ruhe]

S. Giovanardi, D. T. Ksepka, D. B. Thomas A NEW SPHENISCIFORM FOSSIL FROM THE NORTH ISLAND OF NEW ZEALAND FURTHER RESOLVES THE BAUPLAN OF EXTINCT GIANT PENGUINS
New Zealand is a key area for understanding the ancient history of penguins (Order Sphenisciformes). Fossils from New Zealand range in age from Paleocene up to Pleistocene, constituting a sampling period that spans more than 60 million years. The New Zealand fossil record includes many ‘giant’ penguin species (i.e., larger than living penguins) which may have represented an extinct foraging guild. Kairuku, Pachydyptes, Palaeeudyptes and Kumimanu were all from New Zealand but taxa belonging to this guild were found also in Antarctica, South America and Australia. These taxa are characterized by different forelimb proportions and elongated spear-like beaks in addition to their large body sizes. These traits hint at differences in locomotion and foraging when compared with living species, although most body plans for ancient penguins are inferred from largely incomplete skeletons. Here we describe a mostly-complete giant-sized penguin with many bones articulated in life position. The fossil was found in an Oligocene silty mudstone from the North Island of New Zealand and currently represents the most complete pre-Pleistocene vertebrate reported from this region. The specimen shares several morphological features with the New Zealandendemic taxon Kairuku and in preliminary phylogenetic analyses the new fossil forms a clade with this genus. Furthermore, the forelimb elements of Kairuku grebneffi, a similarly-aged giant penguin from the South Island of New Zealand, are almost identical in size when compared with the North Island specimen. The hindlimbs elements of the North Island fossil are significantly longer, exceeding in length all previously described specimens of Kairuku. Moreover, the specimen presents a mixture of characters that show a transitional state between the ancestral body plan found in other Eocene-Oligocene giant penguins and the apomorphic body plan found in Kairuku, providing insight into the diversification of ‘giant’ penguins.

 

[Fred Ruhe]

K. A. Matts, R. E. Fordyce A NEW LOOK AT THE LATE OLIGOCENE PLATYDYPTES PENGUINS OF ZEALANDIA
The dense bones of penguins are predisposed to fossilise, producing an excellent record of fossil penguins in ancient shelf sediments of Zealandia - proto-New Zealand. Of note is the endemic Platydyptes, one of the few described later Oligocene genera, which has been recovered mostly from the bioclastic Otekaike Limestone of Hakataramea, Waitaki region. Other studies have identified Platydyptes as one of the most crownward of the stem penguins, showing it as a precursor for the crown radiation of penguins. First named by Marples in 1952 the genus was last reviewed by Simpson in 1971. Since then new material including partially articulated skeletons, as well as isolated bones, have been collected. Initially separated from each other by the size of the humerus of mature birds, the three named species appear to be distinct: P. novaezealandiae (humerus length = 104mm), P. amiesi (hl = 117mm), and P. marplesi (hl = 93mm). New material from Hakataramea, including OU22804, has shown an unnamed possible fourth species with a humerus (hl = 119mm) distinctly broader than the three named species. Specimen OU22804 is a semi-articulated, partially-complete skeleton from the Otekaike Limestone (Waitakian, latest Oligocene), including several rarer elements; a partial mandible indicates a long spear-like bill, and a quadrate is comparable to Kairuku. OU22116 is also a partial skeleton which has both humeri and the taxonomically diagnostic tarsometatarsus. These partial skeletons alongside the holotypes of the genus have been key in redescription of the genus. Species of Aptenodytes (modern King and Emperor penguins), of similar size to Platydyptes, have helped with reconstruction of the body plan of Platydyptes, especially for interpolating incomplete vertebral columns, information valuable in revealing insight on structure, systematics and lifestyle of Platydyptes

 

[Fred Ruhe]

T. Stidham, Z. Li AVIAN EVOLUTION NEAR THE TIBETAN PLATEAU AND EVIDENCE FOR CENTRAL ASIAN ARIDITY IN THE LATE MIOCENE BASED ON THE FIRST FOSSIL SKELETON OF A SANDGROUSE (AVES: PTEROCLIDAE) FROM THE LINXIA BASIN IN WESTERN CHINA
Adding to the rapidly growing avian fauna of vultures, falcons, pheasants, and ostrich from the Liushu Formation (7.25- 11.1 Ma), is a partial skeleton of a sandgrouse (Columbiformes) that is the most complete fossil of the group known, the oldest record of the group in Asia, and fills a significant temporal gap in their Neogene history. The specimen includes articulated and associated elements of the wing, shoulder girdle, vertebrae, and hind limb. The skeleton preserves a notarium of four fused vertebrae that is present also in pteroclids and columbids. The fossil’s coracoids have short shafts unlike that of stem pteroclids and columbids. The dorsal supracondylar tubercle on the humerus is elongate and differs from that of columbids. The radiale has a much less distinct groove for m. ulnometacarpalis ventralis than the condition in the sandgrouse genus Syrrhaptes. The furcula has a unique elongate (caudodorsally directed) articulation with the coracoid that may be an autapomorphy of this extinct species. Despite occurring within the extant geographic range of the Asian endemic Syrrhaptes, it appears that the fossil is a member of the crown pteroclid clade, and also outside of crown Syrrhaptes. This pteroclid skeleton was found associated with the foot of an ergilornithine gruoid and mammalian remains, and the majority of the sandgrouse skeleton is adjacent to and in contact with a horned bovid skull roof. The mixture of articulated, semicomplete individuals, and broken, unassociated vertebrate remains in otherwise structureless fine-grained sediments parallels that seen at other localities in the Liushu Formation. That taphonomy potentially suggests flood plain deposition during a flash flood event (possibly related to the seasonal Asian monsoon). Males of extant sandgrouse are known for their unusual use of modified breast feathers for absorbing water from permanent water bodies and transporting it long distances to supply their young. Extant and fossil sandgrouse are known from arid habitats across Eurasia and Africa. The interpretation of the Linxia Basin deposits at the northeastern edge of the Qinghai-Tibetan Plateau has been as an arid savannah habitat occupied by a diverse Hipparion fauna. The occurrence of a sandgrouse within this environmental setting reinforces the hypothesis of drying and increased aridity in Central Asia associated coincidentally with the rise of the plateau. Even though fossil fish are unknown in the formation, the discovery of this sandgrouse points to the past presence of permanent water bodies in the area.

 

[Fred Ruhe]

N. Smith, J. Watkins, J. Jay PHYLOGENETIC RELATIONSHIPS OF SULIDAE (AVES: SULIFORMES) INFERRED FROM EXTERNAL MORPHOLOGICAL CHARACTERS AND CONGRUENCE BETWEEN MORPHOLOGICAL AND MOLECULAR DATASETS
Sulidae are a group of seabirds comprised of ten species of gannets and boobies. They were historically classified within the polyphyletic avian order Pelecaniformes, a group notable for long-standing conflicts between molecular and morphological estimates of relationships. Diverse phylogenetic datasets focused on sulid relationships exist for DNA, osteological, and behavioral characters. However, no external morphological (e.g., plumage traits) dataset exists, and no attempt has been made to analyze the varying levels of congruence of these disparate datasets. We present a new dataset of 24 external morphological characters collected for Sulidae and outgroups. The dataset was analyzed using maximum parsimony to infer evolutionary relationships within Sulidae. Our results exhibit some congruence with previous analyses (e.g., monophyly of Sulidae, Morus, and a Sula neubouxii + Sula variegata clade), but differ primarily in: 1) failing to recover Sula monophyly; and 2) the position of Papasula. The latter result confirms that independent forms of character data (nuclear genes, mitochondrial genes, osteology, external morphology) all differ in the placement of this enigmatic species. Trees inferred from osteological, behavioral, and external morphological datasets show variable congruence and conflict with the molecular topology, cautioning against simplistic arguments regarding “molecules vs. morphology” debates in phylogenetics. Additionally, statistical tests reveal that osteological, behavioral, and external morphological datasets all possess significant phylogenetic signal on the molecular tree, and also do not differ significantly from each other in measures of homoplasy or retained synapomorphy. These results lay the groundwork for more rigorous total evidence analyses of sulid phylogeny incorporating disparate data, and also suggest that the relationships of extinct sulids can be robustly resolved within such a framework. Future work requires a two-fold approach of rigorously assessing hypotheses of primary homology in avian morphological characters, and testing hypotheses of convergence using modern phylogenetic comparative methods.

 

[Fred Ruhe]

N. J. Rawlence EXTINCT BIRDS OF NEW ZEALAND: HOW ANCIENT DNA AND MORPHOLOGY IS RAPIDLY INCREASING THE NUMBER OF HUMAN DRIVEN EXTINCTIONS
The arrival of humans in Aotearoa New Zealand resulted in the loss of 50% of its unique biodiversity due to hunting, habitat destruction and predation by introduced predators. New Zealand is unique in that the often confounding effects of humans and climate change can be clearly separated, and studied in isolation. The arrival of humans and the consequent extinctions occured at a time of relative climatic stability. New Zealand's rich Late Quaternary fossil record, spanning the past 60,000 years, and the recent archaeological record, contain the remains of many of New Zealand's extinct avain species. The advent of ancient DNA, combined with morphological analysis, has revolutionised our understanding of New Zealand's extinct avain biodiversity. The current rate of discovery of extinct Late Quaternary birds in New Zealand is unprecidented, with seven new species described since 2009. This talk will highlight several of these new taxa including the Kohatu Shag (Leucocarbo septentrionalis), Pouwa (Cygnus sumnerensis), Waitaha Penguin (Megadyptes antipodes waitaha), Richdale's Penguin (M. antipodes richdalei) and Warham's Penguin (Eudyptes warhami). These examples illustrate the vulnerability of insular island fauna, and consequent biological turnover events, and have implications for 're-wilding' ecosystems and how conservation paleontology can inform the management of threatened species.

Enjoy,

Fred