Thomas A. Stidham

Chinese Academy of Sciences | CAS · Key Laboratory of Vertebrate Evolution and Human Origins

Fossils attributable to the extinct waterfowl clade Presbyornithidae and the large flightless Gastornithidae from the early Eocene (~52–53 Ma) of Ellesmere Island, in northernmost Canada are the oldest Cenozoic avian fossils from the Arctic. Except for its slightly larger size, the Arctic presbyornithid humerus is not distinguishable from fossils o...

Significance Molecular (DNA) studies suggest that birds radiated rapidly in the wake of the Cretaceous–Paleogene mass extinction (66 Ma), diversifying into nearly all the major groups we recognize today. However, fossil evidence for this pattern has been difficult to find because of the poor fossilization potential of small, delicate-boned birds. W...

Significance We report the second most basal clade of the short-tailed birds (Pygostylia) from the Early Cretaceous. The new family Jinguofortisidae exhibits a mosaic assembly of plesiomorphic nonavian theropod characteristics, particularly of the fused scapulocoracoid and more derived flight-related features, further increasing the known ecomorpho...

While pelagornithid or ‘bony-toothed’ bird fossils representing multiple species are known from Antarctica, a new dentary fragment of a pelagornithid bird from the middle Eocene Submeseta Formation on Seymour Island, Antarctica represents a species with a body size on par with the largest known species in the clade. Measurements from the partial ‘t...

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 partial skeleton of a fossil snake is described from the Upper Miocene “Liushu” Formation of the Linxia Basin, Gansu Province, in the northeastern Tibetan Plateau of China. Material preserves rare cranial materials of the palatomaxillary arch, in addition to a series of vertebrae, represents a new species of erycine sand boa, Eryx linxiaensis s...

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...

Fossil evidence is indispensable for studying the derivation, divergence, and dispersal of squirrels as they responded to global Cenozoic climatic and paleoenvironmental change. Among these fossil records, the earliest known definitive fossil squirrels in Eurasia occur after the Eocene/Oligocene Boundary and are slightly younger than the oldest rec...

The independent movements and flexibility of various parts of the skull, called cranial kinesis, are an evolutionary innovation that is found in living vertebrates only in some squamates and crown birds and is considered to be a major factor underpinning much of the enormous phenotypic and ecological diversity of living birds, the most diverse grou...

Whether or not nonavian dinosaur biodiversity declined prior to the end-Cretaceous mass extinction remains controversial as the result of sampling biases in the fossil record, differences in the analytical approaches used, and the rarity of high-precision geochronological dating of dinosaur fossils. Using magnetostratigraphy, cyclostratigraphy, and...

The independent movements and flexibility of various parts of the skull, called cranial kinesis, is an evolutionary innovation that is found in living vertebrates only in some squamates and crown birds, and considered to be a major factor underpinning much of the enormous phenotypic and ecological diversity of living birds, the most diverse group o...

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 latest Paleocene charophyte flora collected from the South Gobi area in the Junggar Basin, western China, includes the geographically widespread taxa Peckichara torulosa var. varians (Dollfus and Fritel, 1919) Sanjuan, Vicente, and Eaton, 2020, Lychnothmanus vectensis (Groves, 1926) Soulié-Märsche, 1989, and Gyrogona lemani capitata Grambast and...

We describe six specimens consisting of cranial remains and associated partial presacral axial series belonging to ornithuromorph birds from the Changma locality of the Lower Cretaceous Xiagou Formation of northwestern Gansu Province, China. Comparison among specimens is limited by the paucity of overlapping elements, their differing exposed views,...

The Spot-billed Pelican (Pelecanus philippensis) is a threatened species of Pelecanidae that was extirpated during the 20th century across much of its Asian geographic distribution, including in the Philippines and China. The idea that this species did not reside in China is in conflict with published reports from the early 20th century and data fr...

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...

With its large size and range of habitats, Texas has one of the most diverse insect faunas of the United States with many endemic species. Despite more than a century of active study, knowledge of the insect diversity in Texas remains incomplete. Here, we report 19 species and subspecies records of Mantodea, Orthoptera, and Phasmatodea for the firs...

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...

Columba congi is an extinct species that was described as part of the Early Pleistocene (~1.7 Ma) fauna from locality 12 of the UNESCO Zhoukoudian or "Peking Man" site in Beijing, China. Only four partial humeri of the original type series of 11 bones can be located, and the features present in those specimens do not support the original diagnosis....

Supplementary Information for "Cretaceous bird with dinosaur skull sheds light on avian cranial evolution"

While the morphology and evolution of the quadrate among early birds and through the evolutionary origin of birds is not well known, we add to knowledge about that past diversity through description of the morphology of the quadrate in the unusually elongate skull of the Cretaceous enantiornithine bird Longipteryx chaoyangensis. The lateral and cau...

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 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...

Early Palaeolithic wooden implements are exceptionally rare. The best known are the spears and throwing sticks from Schöningen, Germany dated to ca. 300–330 thousand years (kyr) ago 1,2 and the 171-kyr old digging sticks from Poggetti Vecchi, Italy ³ . Here, we report a unique assemblage of 35 wooden implements from the site of Gantangqing, southwe...

The relatively extensive fossil record of owls (Aves, Strigiformes) in North America and Europe stands in stark contrast to the paucity of fossil strigiformes from Africa. The first occurrence of a fossil owl from the Paleogene of Africa extends the fossil record of this clade on that continent by as much as 25 million years, and confirms the prese...

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...

Hereditary hierarchy is one of the major features of complex societies. Without a written record, prehistoric evidence for hereditary hierarchy is rare. Intentional cranial deformation (ICD) is a ritualized and cross-generational cultural practice that embodies social identity and cultural beliefs in adults through the behavior of permanently and i...

A new bird coracoid from the Uinta Formation in the Uinta Basin in Utah (USA) records the presence of the only known pangalliform from the middle Eocene of North America, occurring in a >15 million year gap in their history. This fossil represents a new taxon, informally termed the Uintan paraortygid, which is also currently the best-supported reco...

The Spot-billed Pelican (Pelecanus philippensis) is a lesser-known pelican species that experienced a significant reduction across its geographic range during the mid-late twentieth century as the result of extirpation of many populations in Asia. Through direct examination of museum skins, we verified the species identification of four nineteenth...

Hereditary hierarchy is one of the major features of complex societies. Without a written record, prehistoric evidence for hereditary hierarchy is rare. Intentional cranial deformation (ICD) is a cross-generational cultural practice that embodies social identity and culture beliefs in adults through the behavior of altering infant head shape. There...

A new species of stick insect, Diapheromera arena n.sp., from western Texas and New Mexico is the first new species of Diapheromera described from the United States in several decades. It lacks armature on the head of both sexes and has a unique apomorphy of a distinctly swollen third antennal segment that easily differentiates it from other specie...

The fossil avian genus Presbyornis and its relatives (Family Presbyornithidae) are almost universally considered as one of the oldest known filter-feeding specialists among Anseriformes. Such an assumption is based almost entirely on the bill morphology which in Presbyornis is very similar to that of some modern ducks. However, the quadrate bone (k...

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...

A notable reorganization of the waterfowl communities apparently took place across Eurasia during the middle to early late Miocene, when primitive and extinct anatid taxa (e.g. Mionetta) were replaced by more derived forms, including extant genera. However, little is known about the diversity of Eurasian waterfowl and their palaeobiogeography durin...

Two new species of fossil hamsters (Cricetinae, Cricetidae) collected from early Pliocene sediments (∼4.4 Ma) in the Zanda Basin, southwestern Tibet (China), demonstrate greater past diversity among cricetines in the hinterland of the Tibetan Plateau within the Himalayan Range (beyond the previously known ‘Plesiodipus’ thibetensis from the late Mio...

A new fossil specimen from the early Middle Eocene of an Irdin Manha Formation equivalent (Erden Obo Section) in Nei Mongol (Inner Mongolia), China appears to be derived from an ameghinornithid-like species, and may represent the first record of the Ameghinornithidae in Asia. This new specimen exhibits the subcircular lateral condyle outline, the a...

New fossils from the latest Pliocene portion of the Tatrot Formation exposed in the Siwalik Hills of northern India represent the first fossil record of a darter (Anhingidae) from India. The darter fossils possibly represent a new species, but the limited information on the fossil record of this group restricts their taxonomic allocation. The Plioc...

Deltatheroidans are primitive metatherian mammals (relatives of marsupials), previously thought to have become extinct during the Cretaceous mass extinction. Here, we report a tiny new deltatheroidan mammal (Gurbanodelta kara gen. et sp. nov.) discovered at the South Gobi locality in China (Xinjiang Province) that is the first Cenozoic record of th...

Stidham, T.A. & Zelenkov, N.V., September 2016. North American–Asian aquatic bird dispersal in the Miocene: evidence from a new species of diving duck (Anseriformes: Anatidae) from North America (Nevada) with affinities to Mongolian taxa. Alcheringa 41, XXX–XXX. ISSN 0311-5518. Prehistoric intercontinental dispersals are often used to explain the m...

Although molecular divergence dating analyses suggest that the neoavian radiation was well under way by the early Paleocene, bird specimens and localities remain poorly represented for this time period. This paucity of data obscures our understanding of the initial phases of the neoavian diversification, particularly in terms of morphological and e...

A new species of diving duck from lacustrine deposits inside the middle Miocene High Rock Caldera in north-west Nevada (USA) appears to be more closely related to the stiff-tailed ducks Oxyura and Nomonyx than to other Oligocene and Miocene anatid taxa. The new species, Lavadytis pyrenae sp. nov., is represented by 24 fragments of humeri, tibiotars...

The oviraptorosaurian theropod Caenagnathasia was first described from the Late Cretaceous (Turonian) vertebrate assemblage from the Bissekty Formation of the Kyzylkum Desert, Uzbekistan. Here we report a partial pair of oviraptorosaurian fused lower jaws, comprising the symphysial region, from the Upper Cretaceous (Campanian) Iren Dabasu Formation...

Birds are maniraptoran theropod dinosaurs. The evidence supporting the systematic position of Avialae as a derived clade within Dinosauria is voluminous and derived from multiple independent lines of evidence. In contrast, a paucity of selectively chosen data weakly support, at best, alternative proposals regarding the origin of birds and feathers....

The Ameghinornithidae are an enigmatic group of potentially flightless Paleogene birds currently known from three European species. Herein, we report a new fossil that represents the first record of an ameghinornithid-like bird from Africa. The new speci- men was collected from the early Oligocene Jebel Qatrani Formation exposed in the Fayum Depres...

An avian coracoid from the early Pleistocene Qigequan Formation in the Qaidam Basin, Qinghai Province, China, in the northern part of the Qinghai-Tibetan Plateau represents one of the few avian fossils from the region. The specimen is from an individual of a shelduck (Tadorna sp.), and its phylogenetic position is supported by the presence of a pro...

We report a new fossil specimen of a pelican from the Tatrot Formation of the Siwalik Hills, India. It likely represents Pelecanus sivalensis Davies, 1880, the smaller of the two previously published species from the Siwalik Group stratigraphic sequence. This complete tarsometatarsus is the first fossil bone of a pelican collected in India for over...

A humerus and a coracoid from the Early Eocene Wasatch Formation in the Washakie Basin of south-western Wyoming are the oldest materials (by ~2 million years) of the pelecaniform Limnofregata (Aves) and represent a new large species, Limnofregata hutchisoni sp. nov. This fossil is the oldest known member of the frigatebird lineage. Other than its l...

Two new avian fossils from the Late Eocene of Xinjiang in western China appear to document the possible first occurrence of the extinct anseriform group Romainvilliinae (Anatidae) within China and Asia. The tarsometatarsus has several anseriform and anatid characters, and a combination of traits only reported from the romainvilliines among waterfow...

The study of spatial patterns in biotic compositional variability in deep time is key to understanding the macroecological response of species assemblages to global change. Globally warm climatic phases are marked by the expansion of megathermal climates into currently extra-tropical areas. However, there is currently little information on whether...

The fossil record of birds prior to the last ~1 million years of the Paleocene in North America is more poorly known than that of the latest Cretaceous. Lithornithids and rare neognathous birds represent the only known avian records from North America in the middle to late Paleocene. However, late Tiffanian (~ 58 Ma) Bullion Creek and Sentinel Butt...

The early Pliocene is a relatively poorly understood period in southern Africa. Fossil deposits such as Langebaanweg (c. 5.0 Ma) and Makapansgat (c. 2.5 Ma) have each produced large and well-documented faunal assemblages, and it is clear that a significant turnover of fauna occurred between the early and late Pliocene respectively. However, the tem...

A quadrate from the external cave deposits of Plovers Lake in the Bloubank River Valley of South Africa is the first fossil bird to be described from the locality and is the youngest known lovebird fossil from southern Africa. The past presence of Agapornis in the Pleistocene of Gauteng Province, South Africa, hundreds of kilometers from the geogra...

The arboreal camel cricket, Gammarotettix bilobatus Thomas, is abundant and widespread in California. It emerges in mid to late February, survives into late May and early June, and utilizes 8 host-plant species (coast live oak, barberry, Christmas berry, California lilac, California buckeye, Monterey pine, black locust, and California bay), some of...

Fossils of Cretaceous feathers are extremely rare, especially from clastic sediments. Here we report on a partial pennaceous feather collected from the lower Campanian Point Lookout Sandstone of northwestern New Mexico (New Mexico Museum of Natural History locality L-7468). The feather is from a laterally discontinuous shale at the top of the Point...

The previous report of the presence of lovebirds (Agapornis) at the Plio-Pleistocene Kromdraai B fossil locality is confirmed by the identification of a humerus from Member 3. That fossil specimen differs from extant lovebird species in morphology, and its slightly smaller size indicates that it likely represents an extinct taxon. This lovebird spe...

A new species of fossil grasshopper, Mioedipoda reisereri Stidham & Stidham, is the first insect to be described from the Miocene (15.5 million year old) Buffalo Canyon Formation of west-central Nevada. This fossil is identified as an oedipodine and is the oldest supportable band-winged grasshopper from North America. This species appears to be a p...