Review of 2023

Another quiet year for this blog, mostly consisting of conference trip reports, though I also found time to write about Prehistoric Planet Season 2 and a new post on alvarezsaur paleobiology (which is already demanding further followups—such is the nature of science!). Behind the scenes, I've made substantial progress on a variety of research projects, which I hope I'll get to discuss in more detail over the coming year. In addition, I've maintained work on New Dinosaur Alert and Through Time and Clades.

Those who follow me on Tumblr might have noticed that I've started posting a lot about Doraemon on there. It's been refreshing, to be honest, to simply share my thoughts and observations on a media franchise (especially one so extensive yet rarely discussed in English-speaking circles), as opposed to scientific writing where I may feel the need to double-check half a dozen references for every other sentence I write.

I have no intention of halting my scientific communications entirely though, so let's take a look at what 2023 had to offer in maniraptoran research. As always, my coverage of papers about modern birds is necessarily going to be incomplete, so I put more focus on those that have more direct connections to paleontology, such as studies on anatomy, ontogeny, and higher-order phylogeny.

General and non-paravian maniraptorans

• Downy feather fossils from the Zhonggou Formation
  
• Experimental preservation of melanin in feathers
• Morphological disparity and evolutionary rates in the limbs of maniraptorans (and other theropods)
• Review of the evolution of avian nesting behavior
  
• Review of the evolution of contact incubation in maniraptorans
  
• Evolution of claw function in alvarezsaurs and therizinosaurs
• New alvarezsaur Jaculinykus yaruui
  
• Ontogeny of alvarezsaurids
• Range of shoulder motion in Mononykus
  

Holotype of Jaculinykus yaruui (A–C), life restoration by Seiji Yamamoto (D), and phylogenetic diagram showing the known distribution of a bird-like sleeping posture among maniraptorans (E), from Kubo et al. (2023).

• New indeterminate maniraptoran Migmanychion laiyang
• Maniraptoran teeth from the Middle Jurassic of the United Kingdom
  
• Hindlimb musculature of Falcarius
  
• Reconstruction of non-contractile soft tissues in the hindlimb of Nothronychus
  
• Evolution of body shape and mass distribution in pennaraptorans (and other dinosaurs)
• Rarity of molt evidence in Mesozoic pennaraptorans
  
• Evolution of the propatagium in pennaraptorans
• Caenagnathids from the Aguja Formation
  
• Caenagnathids from the Scollard Formation
  
• Feasibility of contact incubation in oviraptorids

Depiction of an oviraptorid incubating its eggs (A) and schematic showing how the "inverted cone" shape of an oviraptorid nest would have increased surface area available for accommodating a large clutch of eggs (B–C), from Hogan (2023).

 General and non-neornithean paravians

• Evolution of the avian-like cephalic thermoregulation system
• Dental microstructure of paravians
• Preservation of phaeomelanin in paravian (and other vertebrate) fossils
  
• Preservation of corneous β-proteins in fossil paravian feathers
  
• Effect of flapping on early paravian locomotion based on robotic modeling
  
• Review of bone histology in dromaeosaurids and troodontids
  
• Plumage coloration of Wulong
  
• Large dromaeosaurids from the Quantou Formation
  
• Dromaeosaurid from the Villalba de la Sierra Formation
• New specimens of Kansaignathus
  
• New specimen of Shri
  

Life restoration of Wulong by Bob Nicholls with coloration informed by analyses of preserved melanosomes, from Croudace et al. (2023).

• Troodontid from the Early Cretaceous of China
• Bone histology of Liaoningvenator
  
• Eggshell mineralization and body temperatures in troodontids
• Enamel biogeochemistry suggests omnivory in troodontids
  
• Avialan tracks from the Wonthaggi Formation
  
• Putative avialan teeth from the Late Cretaceous of Canada reinterpreted as those of crocodylians
• New anchiornithid Fujianvenator prodigiosus
  
• Evidence for folivory in Jeholornis
  

Specimen of Jeholornis that preserves phytoliths as gut contents, suggesting leaf-eating behavior, from Wu et al. (2023).

• Taphonomy of feathers in Sapeornis
• Flight performance of Confuciusornis
  
• New jinguofortisid Cratonavis zhui
• New enantiornithean Castignovolucris sebei
  
• Enantiornithean from the La Huérguina Formation
  
• Molting in juvenile enantiornitheans (based on feathers preserved in Burmese amber)
• Redescription of Dapingfangornis
  
• Diet of pengornithids
• Diet of longipterygids
  
• New specimen of Parabohaiornis
• Quantification of gastral masses in Archaeorhynchus and Iteravis
  
• Locomotor ecology of Ichthyornis
• Femoral blood flow rates in avialans
• Avialan from the La Colonia Formation
  

General and miscellaneous crown birds

• In a Class of Their Own by Gary Ritchison published
  
• Update of Cenozoic fossil birds of Argentina
• Ecological predictors of avian bill and leg length variation
• Ecological and life-history drivers of avian skull evolution
• Avian beak shape correlates with nest material use
• Innovation and elaboration of avian beak shape
  
• Casque ontogeny in birds
  
• Comparative morphology of the avian bony columella

Suitability of modern bird casques as potential analogues for similar skull structures in extinct dinosaurs, from Green and Gignac (2023).

• Review of avian neck evolution, function, and development
• Role of the neck in avian macroevolution and mosaicism
  
• Bird clades with less complex appendicular skeletons tend to have higher species richness
  
• Quantification of avian humeral pneumaticity
• Nonpathological inflammation drives avian pygostyle development
• Quantification of bone surface textures for ontogenetic ageing of bird specimens
  
• Allometry of avian pectoral flight muscles
• Review of form–function relationships in avian bills
  
• Mechanism of avian postural stability
• Radial porosity profiles as a tool for tracing locomotor maturation in avian limb bones
• Functional trade-offs in foot morphology of Australian birds
  
• Evolution of avian hindlimb use
  
• Changes in avian functional diversity
• Decoupled spatiotemporal patterns of avian taxonomic and functional diversity

Phylogenetic distribution of foot dexterity in birds, from Gutiérrez-Ibáñez et al. (2023).

• Review of the avian visual system
• Predictors of avian eye size variation
  
• Evolution of avian eye size
• Review of avian eye color variation
  
• Pupil dynamics in birds (and mammals)
• Blinking mechanisms of birds
  
• Evolution of gaze following in birds (and other archosaurs)
• Review of the avian taste system
  
• Mechanistic hypotheses for proprioceptive sensing within the avian lumbosacral spinal cord
• Morphological evolution of avian wings follows a mechanical sensitivity gradient
• Correlation between avian wing morphology and life history
  
• Phylogenetic comparative analysis of avian alula morphology
• Relationships between avian flight feather count and underlying skeletal size
  
• Review of elongated tail feather function in birds
• Molecular and cellular characterization of avian reticulate scales
• Evolutionary predictors of avian coloration
• Melanin-rich skin color associated with increased net diversification rates in birds

Correlations between habitat use and climate with bird coloration, from Delhey et al. (2023).

• Parental provisioning drives brain size in birds
• Metabolic scaling of birds (and mammals)
• Birds are better at regulating heat loss through their legs than through their bills
  
• Review of avian heterothermy
  
• Review of avian migration genetics
• Determinants of avian mitochondrial genetic diversity
  
• Evolution of avian retroelements in relation to adaptation for arid environments
• Changes in avian body size in the Yucatán Peninsula since the Late Pleistocene
• Variation in avian nest-building behavior
  
• Evolution of extra-pair paternity and paternal care in birds
• Life history variation in birds (and mammals)
  
• Review of mixed-species avian flock classification
  
• Effect of sociality on avian competitive interactions
• Review of the island syndrome in birds
  
• Avian island diversity–area relationships
  
• Strength of the island rule in birds associated with absence of predators
  
• Review of Beringia as an engine of avian speciation
• An elevational phylogeographic diversity gradient in Neotropical birds is decoupled from speciation rates
  
• Review of avian biogeography in Amazonia
• Estimation of undiscovered anthropogenic avian extinctions
  
• Digital reconstruction of cranial suture ontogeny in the common ostrich and Eurasian magpie
• Vegaviids from the López de Bertodano Formation
  
• Jaw anatomy of Vegavis
  
• Rhamphotheca anatomy of pelagornithids from the Eocene of Antarctica
• Bone microstructure of pelagornithids from the Buchak Formation
  
• Covariation in sternum and pelvis shape in waterbirds
• Energy expenditure in seabirds
  
• Eggshell composition and surface properties in avian brood parasites

Depiction of a pelagornithid showing inferred beak structure, from Piro and Acosta Hospitaleche (2023).

Paleognaths

• Evolution of eggshell structure in paleognaths
• Effect of data type on paleognath phylogenetics
• Absence of allopreening in paleognaths
  
• Ostrich femur cast from the Pleistocene of China rediscovered
• Syrinx morphology of the common ostrich
  
• Morphometrics of the appendicular skeleton of common ostriches
  
• Natal down structure of the common ostrich
  
• Eggshell structure and composition in the common ostrich
• Running speed of Opisthodactylus
  
• Ontogeny of the feeding apparatus of greater rheas
• Ontogeny of hindlimb bone texture in greater rheas
  
• Play in juvenile greater rheas
• Diversity of elephant birds based on ancient DNA
• Moa tracks from the Maniototo Conglomerate Formation
  
• Character displacement of egg colors during tinamou speciation
• Atlas of pectoral anatomy in the Andean tinamou

Phylogeny of elephant birds based on ancient DNA, from Grealy et al. (2023).

Galloanserans

• Evolution of the galloanseran quadrate
  
• Locomotor performance of developing galloanserans
  
• New stem-anseriform Anachronornis anhimops and indeterminate galloanseran Danielsavis nazensis
  
• New presbyornithid Murgonornis archeri
  
• New Miocene ducks Lavanttalornis hassleri, Mioquerquedula palaeotagaica, Selenonetta lacustrina, Tagayanetta palaeobaikalensis, and Mionetta defossa (also new genus Caerulonettion for "Mionetta" natator)
• Reevaluation of "Anas" soporata and "Anas" velox as members of Mioquerquedula and Protomelanitta respectively
  
• Binocular vision and foraging in anatids
  
• Phylogeny of the bean goose species complex
• Consistent changes in muscle metabolism underlie dive performance in diving ducks
  
• Effects of speed on foot kinematics of mallards

Skull and vertebrae from the holotype of Anachronornis anhimops, from Houde et al. (2023).

• New possible stem-galliform Tegulavis corbalani
• Putative rusty-margined guan × helmeted guineafowl hybrid refuted
• Reduction of wing area affects estimated stress in flight muscles of chickens
  
• Behavioral and musculoskeletal changes as a result of wing disuse in chickens
• Differential growth of the adductor muscles, eyeball, and brain in chickens
  
• Genetic basis of feathered feet in chickens
  
• Developmental pathway underlying transition of skin appendage fate in chicken embryos
• Cognitive ecology of mirror self-recognition in chickens
• Muscle forces and strain distribution in the femur of Cabot's tragopans
  
• Effect of keratin cortex thickness on iridescent feather colors in common pheasants
  

Miscellaneous neoavians

• New perplexicervicid Perplexicervix paucituberculata
  
• Structure and function of tuberculate neck vertebrae of perplexicervicids
  
• Flamingo egg from the Pleistocene of Mexico
• New Pleistocene sandgrouse Pterocles bosporanus
  
• Structure of the water-holding feathers of Namaqua sandgrouse
  
• Biogeographic history of pigeons
• Evolutionary history of the rock pigeon
  
• New genus Nubotis for the Nubian bustard ("Neotis" nuba)
  
• Role of egg darkness and nest similarity in crypsis of cuckoo eggs

Neck vertebrae of perplexicervicids, from Mayr et al. (2023).

Strisoreans

• Systematics of South American nightjars, including new genera Quechuavis for the Tschudi's nightjar ("Systellura" decussata) and Tepuiornis for the Roraiman nightjar ("Setopagis" whitelyi)
  
• Convergence in hearing-related genes between echolocating birds and mammals
  
• Unorthodox feeding styles drive negative correlation between foot and bill size in hummingbirds
  
• Morphology and niche evolution influence speciation rates in hummingbirds
  
• Absence of song suggests heterogeneity of vocal learning in hummingbirds
• Hummingbird blood traits track oxygen availability across space and time
• Hummingbirds use wing inertial effects to improve maneuverability
  
• Ecological drivers and consequences of torpor in Andean hummingbirds
  
• Hybridization explains rapid gorget color divergence in Heliodoxa hummingbirds
• Phylogenetic discordance in the blue-throated starfrontlet and golden-bellied starfrontlet
• Reevaluation of Lophornis "melaniae" as a synonym of the spangled coquette (Lophornis stictolophus)
  
• New genus Dicranurania for the Mexican woodnymph ("Eupherusa" ridgwayi)

Phylogenetic distribution of unorthodox feeding behaviors in hummingbirds, from Colwell et al. (2023).

Gruiforms and charadriiforms

• New possible stem-limpkin Papulavis annae
• Phylogeny of laterallin and pardirallin rails
• Provenance of the only known egg of the Tristan moorhen
• Ancient mitogenomes of moho and takahē
  
• New Eocene charadriiform Charadriisimilis essexensis
  
• New genus Hesperoburhinus for American dikkops ("Burhinus" bistriatus and "Burhinus" superciliaris)
  
• Systematics of the Kentish plover species complex
• Plains-wanderers from the Pleistocene of Australia
• Cause of genetic diversity declines in whimbrels and curlews
  
• Eurasian woodcocks produce the most brilliant white plumage patches among birds
• Asymmetry of feather ornaments in whiskered auklets

Limb bones from the holotype of Charadriisimilis essexensis, from Mayr and Kitchener (2023).

Phaethoquornitheans

• New stem-tropicbird Clymenoptilon novaezealandicum
  
• Loons from the Liuchungchi Formation
  
• New stem-penguins Kumimanu fordycei and Petradyptes stonehousei
  
• Hydrodynamic performance of penguin wings
  
• Ecomorphological variation of the penguin wing
• Bone histology of Adélie penguins
• Nesting Adélie penguins accrue large quantities of sleep through seconds-long microsleeps
  
• Small penguin skull from the Bahía Inglesa Formation
• New Pliocene penguin Eudyptula wilsonae
  
• Pleistocene decline of the African penguin

Holotype of Clymenoptilon novaezealandicum, from Mayr et al. (2023).

• New stem-albatross Plotornis archaeonautes
• Drivers of shape variation in the compound bill of albatrosses
• Movement of wandering albatrosses suggests sensitivity to infrasound cues at sea
  
• New Pliocene petrel Macronectes tinae
  
• Recently extinct subspecies of Abbott's booby from the Mascarenes
  
• Gannet from the Miocene of Portugal
• Gannet from the Hurupi Formation
  
• Anhingas from the Solimões Formation
  
• New Oligocene cormorant Praecarbo strigoniensis
  
• Phylogeny of microcormorants, including new genus Afrocarbo for the reed ("Microcarbo" africanus) and crowned ("Microcarbo" coronatus) cormorants
  
• New stem-ibis Rhynchaeites litoralis
• New Miocene pelican Pelecanus paranensis
  
• Morphological covariance in skull and hindlimb dimensions of herons
  
• Phylogeny of herons
• Osteology of recently extinct night herons

Phylogeny of herons, from Hruska et al. (2023).

Telluravians

• Pace of avian mitochondrial molecular evolution varies with seasonal migration distance
  
• Genetic evidence for population size expansion in North American boreal birds prior to the Last Glacial Maximum
• Tail feather strength in tail-assisted climbing birds achieved through geometric change
• Skull shape predicts feeding ecology in vultures
  
• New Pliocene condor Vultur messii
  
• Long-term record of diet and nest usage in Andean condors
• Anomalous binocular vision in the African harrier-hawk
  
• Coprolites of bearded vultures from the Pleistocene of Portugal
• New large Pleistocene eagles Dynatoaetus gaffae and Dynatoaetus pachyosteus
  
• Role of culture in dietary specialization of Eurasian griffon vultures
  
• Visual fields of the harpy eagle
  
• Concentration of tropical forest nutrient hotspots generated by harpy eagles
• Obstacle avoidance by Harris's hawks during aerial pursuit

Foot bones of Dynatoaetus gaffae, from Mather et al. (2023).

• Ecomorphology of owl feet
• Binocular field configuration in owls
  
• Convergent evolution of dim light vision between owls and deep-diving whales
  
• Island volcanism predicts pheomelanin-based plumage coloration in the barn owl species complex
  
• Hindlimb muscle architecture of the American barn owl
  
• New Miocene owl Yarquen dolgopolae
  
• New stem-trogon Eotrogon stenorhynchus
  
• Evolution of coloration in coraciiforms
• Diversification of the dollarbird–azure roller species complex
  
• Color diversification of kingfishers
• Genomic signatures of convergent shifts to plunge diving in kingfishers
  
• Phylogenetic discordance in Todiramphus kingfishers
  
• Biomechanical trade-offs in bill shape of barbets
• Phylogeny of Neotropical barbets
• Assessment of evidence for mutualism between greater honeyguides and honey badgers
• Culturally determined interspecies communication between greater honeyguides and humans
  
• Upper beak depression dominates cranial kinesis in woodpeckers
  
• Convergent genomic signatures of local adaptation in downy and hairy woodpeckers
• Phorusrhacid tracks from the Río Negro Formation
  
• Claw function in the red-legged seriema

Phorusrhacid tracks from the Río Negro Formation, from Melchor et al. (2023).

• New Miocene falcon Thegornis sosae
• Innovative problem solving in striated caracaras
• New Pleistocene falcon Falco powelli
  
• New vastanavid Avolatavis europaeus and messelasturids Tynskya brevitarsus and Tynskya crassitarsus
  
• New halcyornithids ?Pulchrapollia eximia and ?Pulchrapollia tenuipes
  
• Decline in dietary breadth of kākāpō
• Shifting drivers of kākāpō decline
• Review of the taxonomy of black cockatoos
• Individual preferences for sound tool design in palm cockatoos
  
• Flexible tool set transport in Tanimbar corellas
• Innovative food-soaking behavior in Tanimbar corellas
• Beak papillae and nerves of the African gray parrot
  
• Mirror responses in African gray parrots
• Changes in amazon parrot diversity after human arrival to the Caribbean
  
• Cranial adaptations of the night parrot
• Phylogeny of lovebirds
• Dual function of prokinesis in the feeding and locomotion of rosy-faced lovebirds
• How yellow-collared lovebirds dissipate heat before, during, and after flight
  
• Fast visual adaptation to dim light in budgerigars
• Role of anterior forebrain pathway of budgerigars in producing learned vocalizations

Holotype of ?Pulchrapollia eximia, from Mayr and Kitchener (2023).

• New stem-passeriform Sororavis solitarius
• Carotenoid-dependent plumage coloration associated with reduced male care in passeriforms
  
• Evolution of ground nesting in passeriforms
• Variable macroevolutionary outcomes of interhemispheric dispersal in passeriforms
• Origins of Indo-Pacific montane avifauna
  
• Phylogeography of passeriforms from Amazonian white-sand ecosystems
• Evolution of nest architecture in tyrannidans
• New genus Protopelma for the Serra do Mar tyrant-manakin ("Neopelma" chrysolophum)
  
• New extant tityrid Schiffornis cracrafti
  
• Phylogeography of royal flycatchers
• New genus Neophilydor for the rufous-rumped ("Philydor" erythrocercum) and slaty-winged ("Philydor" fuscipenne) foliage-gleaners

Phylogenetic distribution of next architecture in tyrannidans, from Ocampo et al. (2023).

• Songbirds that display more complex vocal learning are better problem solvers
• New Oligocene bowerbird Sericuloides marynguyenae
  
• New genus Pinarostola for the marbled ("Pycnopygius" cinereus) and plain ("Pycnopygius" ixoides) honeyeaters
  
• Genomic basis for batrachotoxin resistance in toxic corvideans
• Phylogenetic position of white-crowned shrikes
• Diversification of Cyanolyca jays
• Long-term memory of experienced Mexican jays facilitates problem-solving by naïve group members
  
• Social influences on delayed gratification in Eurasian jays and New Caledonian crows
  
• Phylogenetic position of Nearctic magpies
  
• Western jackdaws can selectively adjust social associations while preserving long-term relationships
  
• Reevaluation of Corvus "fangshannus" as a synonym of the extant common raven (Corvus corax)
  
• Carrion crows flexibly apply statistical inferences based on previous experience
• Genomic basis of leg length divergence in tits
  
• Systematics of larks, including new genus Plocealauda for the Bengal bush lark ("Mirafra" assamica) and closely related species
• Taxonomy of Corypha larks
• Phylogenetic position of the Nicobar bulbul
  
• New genus Stictocerthia for pygmy babblers ("Dasycrotapha" plateni and "Dasycrotapha" pygmaea)

Phylogeny of larks, from Alström et al. (2023).

• Group augmentation underlies the evolution of complex sociality in the superb starling
• New extant thrush, the Darién nightingale-thrush (Catharus arcanus)
  
• Biogeographic history and egg coloration in Turdus thrushes
  
• Signaling function of plumage coloration in the chestnut thrush
• New genus Karoocichla for the Karoo scrub robin ("Cercotrichas" coryphaeus)
• Taxonomy of niltavine flycatchers
  
• Phylogeography of Asian Ploceus weaverbirds
• Combined measures of mimetic fidelity explain imperfect mimicry in the eggs of the cuckoo finch
• Phylogeny of parrotfinches
  
• Mitogenomes of accentors
  
• Acoustic model of the upper vocal tract in the house sparrow
• Introgression underlies phylogenetic uncertainty but not parallel plumage evolution in wagtails
  
• Beak morphometry and morphogenesis across songbird radiations
  
• Exceptionalism of songbird adaptive radiations
• Phylogenetic discordance in buntings
  
• Phylogeny of blue seedeaters
• Physical basis of carotenoid redshift in Ramphocelus tanagers
• Genomic basis of Darwin's finch evolution
• Persistence associated with extractive foraging explains variation in innovation in Darwin's finches