Zhiheng li

University of Texas at Austin | UT · Department of Geological Sciences

Angiosperms became the dominant plant group in early to middle Cretaceous terrestrial ecosystems, coincident with the timing of the earliest pulse of bird diversification. While living birds and angiosperms exhibit strong interactions across pollination/nectivory, seed dispersal/frugivory, and folivory, documentation of the evolutionary origins and...

The toothed members of Pterosauria display an extremely wide range of tooth morphologies that supported a variety of feeding habits. Histological studies on the teeth of different pterosaur clades are potentially valuable in understanding the development of their tooth diversity. In this study, we used histological sections and scanning electron mi...

Although it is commonly considered that, in birds, there is a trend towards reduced dentition, teeth persisted in birds for 90 Ma and numerous macroscopic morphologies are observed. However, the extent to which the microstructure of bird teeth differs from other lineages is poorly understood. To explore the microstructural differences of the teeth...

Chondrocytes with remnants of nuclei and biomolecules were recently reported in two Cretaceous dinosaurs from North America and China. For multiple reasons, it was hypothesized that calcified cartilage (CC) had a better potential than bone to preserve ancient cells. Here we provide the first experimental test to this hypothesis by focusing on the m...

As one of the mysteries volant vertebrates, pterosaurs were completely extinct in the K-Pg extinction event, which hampered our understanding of their flight. Recent studies on pterosaur flight usually use birds as analogies, since their shoulder girdle share many features. However, it was also proposed that these two groups may differ in some crit...

Angiosperms became the dominant plant group in early to middle Cretaceous terrestrial ecosystems, coincident with the timing of the earliest pulse of bird diversification. While birds and angiosperms exhibit strong interactions across pollination/nectivory, seed dispersal/frugivory, and folivory, documentation of the evolutionary origins and constr...

The Cretaceous is a critical time interval that encompasses explosive diversifications of terrestrial vertebrates, particularly the period when the earliest-branching birds, after divergence from their theropod ancestors, evolved the characteristic avian Bauplan that led eventually to their global radiation. This early phylogenetic diversity is ove...

Most modern birds have scales covering feet, but our knowledge of early avian scales is limited, mainly due to their scarcity in the fossil record. Here we describe the morphological details of scutellate and interstitial scales preserved in IVPP V15077, a specimen of the Early Cretaceous bird Gansus from the Changma Basin in northwestern Gansu Pro...

Significance Owls, with their largely nocturnal habits, contrast strikingly with the vast majority of diurnal birds. A new spectacular late Miocene owl skeleton from China unexpectedly preserves the oldest evidence for daytime behavior in owls. The extinct owl is a member of the clade Surniini, which contains most living diurnal owl species. Analys...

A unique form of melanosomes contributing to brilliant iridescent colors in modern bird feathers, previously unknown in fossil birds, is identified in the Early Cretaceous bird Eoconfuciusornis. The discovery highlights the complexity of plumage color nanostructures utilized early in bird evolution as far back as 130 million years ago.

The globally distributed extinct clade Enantiornithes comprises the most diverse early radiation of birds in the Mesozoic with species exhibiting a wide range of body sizes, morphologies, and ecologies. The fossil of a new enantiornithine bird, Brevirostruavis macrohyoideus gen. et sp. nov., from the Lower Cretaceous Jiufotang Formation in Liaoning...

Previous findings on dinosaur cartilage material from the Late Cretaceous of Montana suggested that cartilage is a vertebrate tissue with unique characteristics that favor nuclear preservation. Here, we analyze additional dinosaur cartilage in Caudipteryx (STM4-3) from the Early Cretaceous Jehol biota of Northeast China. The cartilage fragment is h...

Here we report a new avian fossil from the Late Miocene Linxia Basin, Northwest China, with exceptional soft-tissue preservation. This specimen preserves parts of cervical vertebrae and tracheal rings that are typically ostrich-like, but cannot be diagnosed at the species level. Therefore, the fossil is referred to Struthio sp. The new specimen was...

The transformation of the bird skull from an ancestral akinetic, heavy, and toothed dino-saurian morphology to a highly derived, lightweight, edentulous, and kinetic skull is an innovation as significant as powered flight and feathers. Our understanding of evolutionary assembly of the modern form and function of avian cranium has been impeded by th...

The discovery in the 1980's that DNA could be extracted and sequenced from extinct animals opened-up a whole new area of research in paleobiology. The oldest authenticated sequence ever recovered is between 1.65 and 1.1 million years (My) old and extrapolation models on DNA degradation suggest that this is close to the temporal limit of DNA surviva...

The recent finding of a fossil entombed in a Late Cretaceous amber-Oculudentavis khaungraae-was claimed to represent a humming bird-sized dinosaur. Regardless of the intriguing evolutionary hypotheses about the bauplan of Mesozoic dinosaurs (including birds) posited therein, this enigmatic animal demonstrates various morphologies resembling lizards...

As key components of the tetrapod pectoral girdle, the scapula and coracoid have played a significant role in the evolution of forelimb locomotion among terrestrial vertebrates. The transition from a rigid fused scapulocoracoid in ancestral non-avian theropods to a presumably more flexible separated scapula-coracoid in early birds is considered to...

Here we report a new avian fossil from the Late Miocene Linxia Basin, Northwest China, with exceptional soft-tissue preservation. This specimen preserves parts of cervical vertebrae and tracheal rings that are typically ostrich-like, but cannot be diagnosed at the species level. Therefore, the fossil is referred to Struthio sp. The new specimen was...

Iodine‐based contrasting agents for computed tomography (CT) have been used for decades in medicine. Agents like Lugol's iodine enhance the contrasts between soft tissues and mineralized (skeletal) tissues. Because a recent study on extant avian heads showed that iodine–ethanol (I2E) is a better contrast enhancer overall than the standard Lugol's i...

The nearly complete skull of a raven (Aves, Corvidae) is reported from middle Pleistocene sediments (∼450–580 ka) of Jinyuan Cave near the city of Dalian on the Liaodong Peninsula of Liaoning Province, China. The new fossil closely resembles that of the Common Raven (Corvus corax), a species with a Holarctic extant distribution. It is one of the re...

Gastroliths, where preserved, can provide indirect evidence regarding diet in extinct avian and non-avian dinosaurs. Masses of gastroliths consistent with the presence of a gastric mill are preserved in many Early Cretaceous Jehol birds mostly belonging to the Ornithuromorpha. Gastroliths are also present in basal birds Sapeornis and Jeholornis in...

The early evolution of flight is one of the most studied topics in vertebrate paleontology. Living birds have evolved to utilize a variety of flight styles, but studies focused on inferring flight strategies in Mesozoic birds are often contradictory and without a clear consensus, making it necessary to find additional informative characteristics th...

Yanornithidae is an Early Cretaceous ornithuromorph clade that preserves the oldest direct evidence indicative of a piscivorous diet in avian evolution. The family hitherto contained only a single genus Yanornis and two putative species. The yanornithids are readily distinguishable from other Mesozoic avians in having a long rostrum packed with num...

The remains of ovarian follicles reported in nine specimens of basal birds represents one of the most remarkable examples of soft-tissue preservation in the Early Cretaceous Jehol Biota. This discovery was immediately contested and the structures alternatively interpreted as ingested seeds. Fragments of the purported follicles preserved in an enant...

Living birds are unique among vertebrates in the formation of a female-specific bone tissue called medullary bone (MB) that is strictly associated with reproductive activity. MB is a rapidly mobilized source of calcium and phosphorus for the production of eggshell. Among living taxa, its skeletal distribution can be highly extensive such that it ev...

Background: Tooth morphology within theropod dinosaurs has been extensively investigated and shows high disparity throughout the Cretaceous. Changes or diversification in feeding ecology, i.e., adoption of an herbivorous diet (e.g., granivorous), is proposed as a major driver of tooth evolution in Paraves (e.g., Microraptor, troodontids and aviala...

The partial skeleton of a new extinct taxon, Linxiavis inaquosus, from the Liushu Formation (6–9 Ma) at the edge of the Tibetan Plateau in Gansu Province, China is the most substantial known fossil record of sandgrouse (Pteroclidae). While adding to the rapidly growing known Liushu avian fauna of vultures, falcons, pheasants, and ostrich, this new...

Though a tradeoff between growth rate and locomotor performance has been proposed, empirical data on this relationship are still limited. Here we statistically analyze the associations of growth rate and flight ability in birds by assessing how growth rate is correlated with three wing parameters of birds: flight muscle ratio, wing aspect ratio, an...

The pterosaur is the first known vertebrate clade to achieve powered flight. Its hyoid apparatus shows a simplification similar to that of birds, although samples of the apparatus are rare, limiting the ability to make an accurate determination. In this study we reveal a new pterosaur specimen, including the first definite basihyal. Through the com...

Living birds are unique among vertebrates in the formation of a female-specific bone tissue called medullary bone (MB) that is strictly associated with reproductive activity. MB is a rapidly mobilized source of calcium and phosphorus for the production of eggshell. Among living taxa, its skeletal distribution can be highly extensive such that it ev...

Despite having one of the most robust fossil records within core-gruiform birds (rails, cranes, and allies), the biogeographic history of Gruidae (cranes) and key drivers of diversification within this group remain largely unknown. The Eogruidae of Eurasia represent some of the earliest known crane-like fossils. Here, we present description of a ne...

The avian predentary is a small skeletal structure located rostral to the paired dentaries found only in Mesozoic ornithuromorphs. The evolution and function of this enigmatic element is unknown. Skeletal tissues forming the predentary and the lower jaws in the basal ornithuromorph Yanornis martini are identified using computed-tomography, scanning...

Most living birds exhibit cranial kinesis—movement between the rostrum and braincase—in which force is transferred through the palatal and jugal bars. The palate alone distinguishes the Paleognathae from the Neognathae, with cranial kinesis more developed in neognaths. Most previous palatal studies were based on 2D data and rarely incorporated data...

Understanding non-crown dinosaur reproduction is hindered by a paucity of directly associated adults with reproductive traces. Here we describe a new enantiornithine, Avimaia schweitzerae gen. et sp. nov., from the Lower Cretaceous Xiagou Formation with an unlaid egg two-dimensionally preserved within the abdominothoracic cavity. Ground-sections re...

During the dinosaur–bird transition, feathers of bird ancestors must have been molecularly modified to become biomechanically suitable for flight. We report molecular moieties in fossil feathers that shed light on that transition. Pennaceous feathers attached to the right forelimb of the Jurassic dinosaur Anchiornis were composed of both feather β-...

In its most basic conception, a novelty is simply something new. However, when many previously proposed evolutionary novelties have been illuminated by genetic, developmental, and fossil data, they have refined and narrowed our concept of biological "newness." For example, they show that these novelties can occur at one or multiple levels of biolog...

The tongue, with fleshy, muscular, and bony components, is an innovation of the earliest land-dwelling vertebrates with key functions in both feeding and respiration. Here, we bring together evidence from preserved hyoid elements from dinosaurs and outgroup archosaurs, including pterosaurs, with enhanced contrast x-ray computed tomography data from...

Major morphological evolution of bony hyoid traits in bird-line archosaurs with new data obtained from Avialae, Palaeognathae, and Neognathae. The hyoid elements are labeled as abbreviation, pg-paraglossal, bh-basihyal, cb-ceratobranchial, ep-epibranchial. Bony hyoid characters include: (1) origin of the narrow, arrow-shaped basihyal (not always mi...

Material of extinct taxa examined. Published specimens are indicated with an associated reference. (DOCX)

Homologous muscles proposed across reptilians and examined in this project. Muscles experiencing major shifts, or considered as neomorphs of birds, are indicated in bold face; dash lines indicate it is not present. All proposed homologies were reviewed from previous studies and new proposed homologies are indicated with an asterisk (*). (DOCX)

Character list used to reconstruct the major transitions of hyolingual evolution with Archosaria. (DOCX)

Data matrix (character list and coding). (DOCX)

Parsimony-based ancestral state reconstruction of hyoid features summarized in Fig 3 and the supplemental tables. Characters numbers correspond to states described in Supplemental Data Files 1, 2: the character descriptions and matrix. (JPG)

Skulls of basal archosaurs and non-avian dinosaurs with associated hyoids evaluated. a, Euparkeria capensis (SAM 5867); b, Jeholosaurus shangyuanensis (IVPP V12530); c, Gongbusaurus wucaiwanensis. (IVPP 14559); d, Massospondylus carinatus (cast, BP/1/4934); e, Syntarsus kayentakatae (MNA V2623); f, Similicaudipteryx yixianensis (STM22-6); g, Sinosa...

Avialan skulls with associated hyoid elements preserved. a, Confuciusornis sanctus (IVPP 13175); b, Confuciusornis sp. (STM 13–6); c, Rapaxavis pani (DNHM D2522); d, Sulcavis geeorum (BMNH ph 000805); e, Longusunguis kurochkini (IVPP V17864); f, Yanornis martini (IVPP V12558); g and h, photograph and line drawing of Hongshanornis sp. (STM 7–56). Th...

Modifications to the upper vocal tract involving hyper-elongated tracheae have evolved many times within crown birds, and their evolution has been linked to a ‘size exaggeration’ hypothesis in acoustic signaling and communication, whereby smaller-sized birds can produce louder sounds. A fossil skeleton of a new extinct species of wildfowl (Gallifor...

Significance We report an Early Cretaceous bird from 120 My ago that has a completely fused carpometacarpus and pelvis, pushing back the date for these avian traits by over 40 My. We suggest that this taxon grew more rapidly than other basal birds, but the degree of bone fusion is not causally linked with growth pattern in primitive birds. We hypot...

The interplay between the pectoral module (the pectoral girdle and limbs) and the pelvic module (the pelvic girdle and limbs) plays a key role in shaping avian evolution, but prior empirical studies on trait covariation between the two modules are limited. Here we empirically test whether (size-corrected) sternal keel length and ilium length are co...

R code

1000 time-calibrated phylogenetic trees used in present study

Raw data and ecological group

Supplementary Figures, Supplementary Table and Supplementary References

The hindlimb of theropod dinosaurs changed appreciably in the lineage leading to extant birds, becoming more ‘crouched’ in association with changes to body shape and gait dynamics. This postural evolution included anatomical changes of the foot and ankle, altering the moment arms and control of the muscles that manipulated the tarsometatarsus and d...

From complex songs to simple honks, birds produce sounds using a unique vocal organ called the syrinx. Located close to the heart at the tracheobronchial junction, vocal folds or membranes attached to modified mineralized rings vibrate to produce sound. Syringeal components were not thought to commonly enter the fossil record, and the few reported...

Neogene fossils of Old World vultures (Aegypiinae and Gypaetinae) are known from both Old World and New World records. There are no extant Old World vultures in the Americas today, although a large diversity of Gypaetinae is known from Miocene to late Pleistocene records. Despite a comparatively large number of North American gypaetine fossils, com...

Diffusible iodine-based contrast-enhanced computed tomography presents a comparatively new tool kit for imaging fine-scale three-dimensional phenotypes that is rapidly becoming standard anatomical practice. However, relatively few studies have attempted to look at subtle differences in staining protocols or attempted to model tissue reactions to ga...

Table S3. Comparisons of iodine‐based contrast agents with alternatives commonly used in contrast‐enhanced μCT imaging.

Table S1. A Microsoft excel file containing the contents of Table 1 along with additional columns of specimen preparation and imaging parameters for readers to manipulate and use for comparing and contrasting various aspects of specimen affinities, sizes, preparation regimes, and μCT imaging.

Table S2. This sample reporting spreadsheet, or a modified version thereof, is intended to be helpful for ensuring the full documentation (and later reporting) of specimen storage, preparation, and CT‐scanning parameters at each stage of diceCT imaging research.

Morphologists have historically had to rely on destructive procedures to visualize the three-dimensional (3-D) anatomy of animals. More recently, however, non-destructive techniques have come to the forefront. These include X-ray computed tomography (CT), which has been used most commonly to examine the mineralized, hard-tissue anatomy of living an...

Within Anseriformes, waterfowl (ducks, geese, and swans) exhibit three specialized feeding modes that are distinctive among Aves: filter-feeding with fine and dense keratinous lamellae on a flat, mediolaterally expanded bill; cropping or grazing vegetation with large and robust lamellae with a dorsoventrally expanded bill; and sharp lamellae associ...