Michael Habib

University of California, Los Angeles | UCLA · Department of Medicine

Pterosaurs thrived in and around water for 160 + million years but their take-off from water is poorly understood. A purportedly low floating position and forward centre of gravity barred pterosaurs from a bird-like bipedal running launch. Quadrupedal water launch similar to extant water-feeding birds and bats has been proposed for the largest pter...

Pterosaurs were the first vertebrate flyers and lived for over 160 million years. However, aspects of their flight anatomy and flight performance remain unclear. Using laser-stimulated fluorescence, we observed direct soft tissue evidence of a wing root fairing in a pterosaur, a feature that smooths out the wing–body junction, reducing associated d...

In the recent study in Current Biology by Pei and colleagues¹, we used two proxies — wing loading and specific lift — to reconstruct powered flight potential across the vaned feathered fossil pennaraptorans. The results recovered multiple origins of powered flight. We respectfully disagree with the criticism raised by Serrano and Chiappe² that wing...

The study of early theropod flight involves avialans as well as other pennaraptorans. It requires the study of anatomy that is familiar to the modern ornithologist, but also very different and alien. Early theropod flight therefore necessitates study methods that can incorporate what we know about sophisticated powered and unpowered flight in livin...

The origin of flight in birds and its relationship to bird origins itself has achieved something of a renaissance in recent years, driven by the discovery of a suite of small-bodied taxa with large pennaceous feathers. As some of these specimens date back to the Middle Jurassic and predate the earliest known birds, understanding how these potential...

Uncertainties in the phylogeny of birds (Avialae) and their closest relatives have impeded deeper understanding of early theropod flight. To help address this, we produced an updated evolutionary hypothesis through an automated analysis of the Theropod Working Group (TWiG) coelurosaurian phylogenetic data matrix. Our larger, more resolved, and bett...

The rachises of extant feathers, composed of dense cortex and spongy internal medulla, are flexible and light, yet stiff enough to withstand the load required for flight, among other functions. Incomplete knowledge of early feathers prevents a full understanding of how cylindrical rachises have evolved. Bizarre feathers with unusually wide and flat...

Limb length, cursoriality and speed have long been areas of significant interest in theropod paleobiology, since locomotory capacity, especially running ability, is critical in the pursuit of prey and to avoid becoming prey. The impact of allometry on running ability, and the limiting effect of large body size, are aspects that are traditionally ov...

Evolution of birds from non-flying theropod dinosaurs is a classic evolutionary transition, but a deeper understanding of early flight has been frustrated by disagreement on the relationships between birds (Avialae) and their closest theropod relatives. We address this through a larger, more resolved evolutionary hypothesis produced by a novel auto...

Animal flight is ecologically important and has a long evolutionary history. It has evolved independently in many distantly related clades of animals. Powered flight has evolved only three times in vertebrates, making it evolutionarily rare. Major recent fossil discoveries have provided key data on fossil flying vertebrates and critical insights re...

This study addresses questions related to the size limits of flying birds and tradeoffs associated with the evolution of large size. Flight imposes unique limits on size in animals, and as such, form and function in large flyers can provide unique insights regarding the mechanical and physiological limits of vertebrate animals. We focused on specia...

Pterosaurs are most well‐known for their expanded and altered forelimbs, which supported muscular membrane wings. Indeed, pterosaurs possessed one of the most derived hand morphologies of any vertebrate animal. However, several pterosaur lineages also possessed enormously expanded cranial and cervical proportions. The most extreme cases occur withi...

The bizarre scansoriopterygid theropods Yi and Ambopteryx had skin stretched between elongate fingers that form a potential membranous wing. This wing is thought to have been used in aerial locomotion, but this has never been tested. Using laser-stimulated fluorescence imaging, we re-evaluate their anatomy and perform aerodynamic calculations cover...

The evolution of flight in feathered dinosaurs and early birds over millions of years required flight feathers whose architecture features hierarchical branches. While barb-based feather forms were investigated, feather shafts and vanes are under-studied. Here, we take a multidisciplinary approach to study their molecular control and bio-architectu...

Limb length, cursoriality and speed have long been areas of significant interest in theropod paleobiology as locomotory capacity, especially running ability, is critical in not just in prey pursuit but also to avoid become prey oneself. One aspect that is traditionally overlooked is the impact of allometry on running ability and the limiting effect...

Azhdarchid pterosaurs have been known since 1972 from upper Campanian deposits of Alberta, Canada. Originally represented by only very fragmentary remains tentatively assigned to the genus Quetzalcoatlus, additional material uncovered over the years has revealed that the taxonomic identity of the Alberta pterosaur material is at odds with this in t...

Birds utilize a unique structure, called a syrinx, for the production of their vocalizations. The origins of the syrinx are not well understood. New work, utilizing first principles–based models, suggests that a key element in selection for the early syrinx might be the position of this vocal structure: although the larynx sits at the cranial end o...

A cervical vertebra of the large, pelagic pterodactyloid pterosaur Pteranodon sp. from the Late Cretaceous Niobrara Formation of Kansas, USA is significant for its association with a tooth from the large lamniform shark, Cretoxyrhina mantelli . Though the tooth does not pierce the vertebral periosteum, the intimate association of the fossils—in whi...

We describe an exquisitely preserved new avian fossil (BMNHC-PH-919) from the Lower Cretaceous Yixian Formation of eastern Inner Mongolia, China. Although morphologically similar to Cathayornithidae and other small-sized enantiornithines from China’s Jehol Biota, many morphological features indicate that it represents a new species, here named Juno...

Palaeopropithecids, or " sloth lemurs, " are a diverse clade of large-bodied Malagasy subfossil primates characterized by their inferred suspensory positional behavior. The most recently discovered genus of the palaeopropithecids is Babakotia, and it has been described as more arboreal than Mesopropithecus, but less than Palaeopropithecus. In this...

Background: Powered flight is implicated as a major driver for the success of birds. Here we examine the effectiveness of three hypothesized pathways for the evolution of the flight stroke, the forelimb motion that powers aerial locomotion, in a terrestrial setting across a range of stem and basal avians: flap running, Wing Assisted Incline Runnin...

Calculations. Spreadsheet for WAIR and leaping height calculations.

Body width estimation. Furcula width for Deinonychosaurians and early avians used to calculate body width estimate.

WAIR calculation using ALL flapping rate. WAIR values using flap rate from regression from Jackson (2009) all taxa.

Equation description and justifications. Explanation for equations used.

Flap running. Increased in velocity after 10 iterations for flap running analysis.

HOrixontal jumping. Horizontal distance gain due to flap based thrust for non-avian theropods and Archaeopteryx.

Leaping take off values using ALL. Body weight support values for ground based take off with a leaping speeds of 3.8, 4.1 and 5.1 m/s using flap rate from regression from Jackson (2009) all taxa.

Leaping take off values using GF. Body weight support values for ground based take off with a leaping speeds of 3.8, 4.1 and 5.1 m/s using flap rate from regression of ground foraging birds from Jackson (2009).

WAIR and leaping takeoff based on previous models of Microraptor, Archaeopteryx, Caudipteryx and Protoarchaeopteryx. WAIR and leaping takeoff values for models taken from the literature. Data for Archaeopteryx from Yalden (1984), Microraptor specimens from: Chatterjee & Templin (2007), Alexander et al. (2010) and Dyke et al. (2013). Caudipteryx and...

Extant avian nexus. Nexus file for the Modified flapping rate regression. Nodal dates form Jetz et al. (2012). Taxa and measurements from Askew, Marsh & Ellington (2001) and Jackson (2009).

Humerus percentage of forelimb. Humerus percentage of forelimb calculation compared to bodysize in avian and non-avian theropods.

WAIR calculation using MOD flapping rate. WAIR values using flap rate from regression based on modified dataset adding galliform birds from Askew, Marsh & Ellington (2001) and Jackson (2009).

Vertical jumping. Height gain due to flap based thrust for non-avian theropods and Archaeopteryx.

Theropod mapping. Mapping of W.A.I.R. values across theropod and early avian phylogeny. Topology based on Dececchi & Larsson (2013).

Measurement data. Measurement data for non-avian and avian theropods used in this analysis.

WAIR calculation using GF flapping rate. WAIR values using flap rate from regression of ground foraging birds from Jackson (2009).

Modelling passerine bird take off. Take off calculations for passerine birds from Jackson (2009).

Leaping take off values using MOD. Body weight support values for ground based take off with a leaping speeds of 3.8, 4.1 and 5.1 m/s using flap rate from regression based on modified dataset adding galliform birds form Askew, Marsh & Ellington (2001) and Jackson (2009).

Fossils of enormous extinct seabirds are now illuminating how such behemoths took wing

The hugely extended neck of giant sauropods, while possibly advantageous in feeding, could have carried important energetic costs. Inertial effects could result in significant surges of the neck during locomotion. Moving blood to the upper neck and head could also be costly in sauropods, particularly if the neck was habitually elevated, since the c...

The hugely extended neck of giant sauropods, while possibly advantageous in feeding, could have carried important energetic costs. Inertial effects could result in significant surges of the neck during locomotion. Moving blood to the upper neck and head could also be costly in sauropods, particularly if the neck was habitually elevated, since the c...

The leading edge and shape of the pterosaur wing is constrained by the skeleton. Although it has long been known that at least some pterosaurs had posteriorly curved distal wing phalanges, affecting the shape of the wingtip, this has been little studied despite that this may have profound effects on flight performance. Here we examine the evidence...

Despite being known for nearly two centuries, new specimens of the derived non-pterodactyloid pterosaur Rhamphorhynchus continue to be discovered and reveal new information about their anatomy and palaeobiology. Here we describe a specimen held in the collections of the Royal Tyrrell Museum of Palaeontology, Alberta, Canada that shows both preserva...

Palaeopropithecids, or 'loth lemurs', are a diverse clade of large-bodied Malagasy subfossil primates characterized by their inferred suspensory positional behaviour. The most recently discovered genus of the family is Babakotia. This genus has been described as more arboreal than Mesopropithecus, but less than Palaeopropithecus. For better underst...

Microraptorines are a group of predatory dromaeosaurid theropod dinosaurs with aerodynamic capacity. These close relatives of birds are essential for testing hypotheses explaining the origin and early evolution of avian flight. Here we describe a new 'four-winged' microraptorine, Changyuraptor yangi, from the Early Cretaceous Jehol Biota of China....

Objectives: This study correlates the Singing Voice Handicap Index (SVHI) scores with videostrobolaryngoscopy in healthy professional singers as a measure of self-perceived vocal health versus actual pathology seen on examination. The objective was to measure the strength of self-assessment among professional singers and determine if there is a be...

The discovery of Hongshanornis longicresta, a small ornithuromorph bird with unusually long hindlimb proportions, was followed by the discovery of two closely related species, Longicrusavis houi and Parahongshanornis chaoyangensis. Together forming the Hongshanornithidae, these species reveal important information about the early diversity and morp...

We present an annotated and illustrated catalogue of all original fossils, casts, and sculpted replicas of pterosaur specimens from the Upper Jurassic Solnhofen limestones of southern Germany that are housed at Carnegie Museum of Natural History (Pittsburgh, Pennsylvania, U.S.A.). The museum obtained its substantial Solnhofen pterosaur fossil colle...

The study of biomechanics most often takes a classic adaptationist approach, examining the functional abilities of organisms in relation to what is allowed by physical parameters. This approach generally assumes strong selection and is less concerned with evolutionary stochasticity in determining the presence of biological traits. It is equally imp...

The evolution of powered flight in birds remains a contentious issue in vertebrate paleontology. The small dromaeosaurid dinosaur Microraptor gui preserves evidence of extensive, lift-generating feathers on each manus and forearm, but also preserves evidence of lift-generating feathers associated with the hindlimbs, effectively forming a pair of "...

Microraptoran dinosaurs may have experienced intrinsic difficulties with pitch control because they retained a trunk of typical dromaeosaurid proportions, as opposed to the shortened trunk of ornithurine birds. As a result, any appreciable forward sweep of the wings could bring the center of lift in front of the center of gravity, resulting in a po...

Palaeopropithecids or “sloth lemurs” are a diverse clade of large-bodied Malagasy subfossil primates characterized by their suspensory positional behaviors. The most recently discovered genus of the family is Babakotia. This species has been described as more arboreal than Mesopropithecus but less than Palaeopropithecus. A remarkably complete skele...

Structural strength (section moduli) for humeri and femora of several living species of wing-propelled divers, along with two species of Tonsala. (DOC)

The plotopterids (Aves, Plotopteridae) were a group of extinct wing-propelled marine birds that are known from Paleogene-aged sediments (Eocene to Miocene), mostly around the Pacific Rim (especially Japan and the northwest coast of North America). While these birds exhibit a strikingly similar wing morphology to penguins (Spheniscidae), they also s...

The size and flight mechanics of giant pterosaurs have received considerable research interest for the last century but are confused by conflicting interpretations of pterosaur biology and flight capabilities. Avian biomechanical parameters have often been applied to pterosaurs in such research but, due to considerable differences in avian and pter...

Mass-specific bone strength was examined in the forelimb and hindlimb of 64 species of birds to determine if aquaflying birds (which utilize the wings for propulsion underwater) differ in their skeletal strength compared with other avian taxa. Long bone strengths were estimated from cross-sectional measurements. Compared with the expectation from g...

Analyses of life-history, ecological, and geographic trait differences among species, their causes, correlates, and likely consequences are increasingly important for understanding and conserving biodiversity in the face of rapid global change. Assembling multispecies trait data from diverse literature sources into a single comprehensive data set r...

Pterosaurs faced unique challenges while launching into flight, especially from the ground. The largest pterosaurs far exceeded the size of the largest known flying birds (both living and fossil). This implies that pterosaurs were able to launch and fly at very high body masses. Large-bodied flyers face special difficulties in launching, because fl...

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