User:A Cynical Idealist/sandbox3

Source: Wikipedia, the free encyclopedia.

Eudromaeosaurs
Temporal range: Early Cretaceous – Late Cretaceous, 143–66 Ma Possible Kimmeridgian record
Eudromaeosauria diversity, featuring from top left to lower right: Utahraptor, Deinonychus, Velociraptor and Bambiraptor
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: †Dromaeosauridae
Clade: †Eudromaeosauria
Longrich & Currie, 2009
Type species
†Dromaeosaurus albertensis
Matthew & Brown, 1922
Subfamilies
  • †Dromaeosaurinae
    Matthew & Brown, 1922
  • †Saurornitholestinae
    Longrich & Currie, 2009
  • †Velociraptorinae
    Barsbold, 1983

For classification of genera, see text

Eudromaeosauria ("true dromaeosaurs") is a subgroup of terrestrial dromaeosaurid theropod dinosaurs. They were small to large-sized, feathered hypercarnivores (with diets consisting almost entirely of other terrestrial vertebrates) that flourished in the Cretaceous Period.

Eudromaeosaur fossils are known almost exclusively from the northern hemisphere. They first appeared in the early Cretaceous Period (early Aptian stage, about 124 million years ago) and survived until the end of the Cretaceous (Maastrichtian stage, 66 Ma). The earliest known definitive eudromaeosaur is the probable dromaeosaurine Yurgovuchia, from the Cedar Mountain Formation, dated to 139 million years ago.[1] However, the earlier (143-million-year-old) fossils such as those of Nuthetes and several indeterminate teeth dating to the Kimmeridgian stage may represent eudromaeosaurs.[2][3]

While other dromaeosaurids filled a variety of specialized ecological niches, mainly those of small predators or larger fish-eating forms, eudromaeosaurs functioned as large-bodied predators of often medium- to large-sized prey. Aside from their generally larger size, eudromaeosaurs are characterized by several features of the foot.

History of study

An illustration of the holotype of Dromaeosaurus from 1922

The subfamily Dromaeosaurinae was first erected in 1922 by Matthew and Brown as a part of the "Deinodontidae" (now named Tyrannosauridae).[4] Today, Dromaeosaurinae is part of the larger clade Eudromaeosauria, and it has been formally defined as a monophyletic group including Dromaeosaurus and all the other dromaeosaurs closer to it than to Velociraptor, Microraptor, Passer and Unenlagia.[5]

Eudromaeosauria itself was first defined as a node-based clade by Nick Longrich and Philip J. Currie in 2009, as the most inclusive natural group containing Dromaeosaurus, Velociraptor, Deinonychus, and Saurornitholestes, their most recent common ancestor and all of its other descendants. The various "subfamilies" have also been redefined as clades, usually defined as all species closer to either Velociraptor, Dromaeosaurus, or Saurornitholestes than to either of the other two.[6]

This group is further subdivided into three subfamilies: Dromaeosaurinae, Velociraptorinae, and Saurornitholestinae. Dromaeosaurines are usually found to consist of medium- to giant-sized species, with generally box-shaped skulls while the other subfamilies generally have narrower snouts. Velociraptorinae has traditionally included the more slender-snouted species which are found primarily in Asia, although this group may also include North American genera like Dineobellator and Deinonychus. Saurornitholestinae, the most recently-named subfamily, typically consists of smaller species with shortened snouts. A number of eudromaeosaurs have not been assigned to any particular subfamily, because they are too poorly preserved to be placed confidently in phylogenetic analysis.[7]

Most eudromaeosaur genera are known from only 1-2 specimens. The major exceptions to this are Deinonychus (35 specimens),[8] Utahraptor (2 described, several undescribed specimens)[9][10] Saurornitholestes (over 70 specimens)[11] Velociraptor (10 very complete specimens),[12] and Dromaeosaurus (20 specimens).[13]

Anatomy

Reconstructions of several dromaeosaurids including four eudromaeosaurs

Eudromaeosaurs were all bipedal and had relatively long arms in comparison to other theropods, like most other maniraptorans. Their wrists exhibited the typical maniraptoran condition in the semi-lunate carpal, which allowed them to fold their arms against their body in the same way that modern birds fold their wings. However unlike many other groups of coelurosaurs, eudromaeosaurs possessed relatively short metatarsals.

Their second toe possessed the archetypal sickle-claw that all known dromaeosaurids bore which was held off the ground so that only the third and fourth toes touched the ground when walking. Eudromaeosaurs also generally possessed long and stiff tails, which are believed to have been used for balance. There is some direct evidence of eudromaeosaurs such as Velociraptor being feathered. Today, it is believed that all eudromaeosaurs were fully-feathered and possessed wings, along with most, if not all, other maniraptorans.

Size

See also: Dinosaur size
The size of three of the largest eudromaeosaurs compared to a human

Eudroameosaurs likely evolved from small ancestors, only around 1 kilogram (2.2 lb) in mass.[14] Later eudromaeosaurs were generally larger than this, with most being less than 2–3 metres (6.6–9.8 ft) long[15] and having masses estimated at around 15–40 kilograms (33–88 lb).[16]

Eudromaeosaurs are also known to have reached relatively large sizes. Among these were the dromaeosaurines Achillobator, at around 6 metres (20 ft),[17][15] and Utahraptor at up to 7 metres (23 ft).[18] The largest eudromaeosaurs are estimated to have been more than 200 kilograms (440 lb) in mass.[16] At least one velociraptorine taxon may have achieved gigantic sizes comparable to those found among the dromaeosaurines. So far, this unnamed giant velociraptorine is known only from isolated teeth found on the Isle of Wight, England. The teeth appear to have belonged to an animal similar in size to the North American genus Utahraptor, but the morphology of the teeth suggests that the large size may only be homoplastic.[19] Remains from giant eudromaeosaurs are also reported from the Bissekty[20] and Bayan Shireh formations.[21]

Skull and tooth morphology

Skull diagram of Dromaeosaurus

The main difference in the skull morphology of eudromaeosaur species that has been observed is that those known from Asia have typically narrower skulls than those in North America. This is generally attributed to a phylogenetic difference (most Asian eudromaeosaurs are considered to be velociraptorines), but an analysis by Mark Powers and colleagues in 2020 demonstrated that dromaeosaur snouts in general increased in length during the Cretaceous. The reason for this is not fully understood, but it has been suggested that this reflects a change in the preferred prey of dromaeosaurs that existed from the Early Cretaceous to the Late Cretaceous.[21]

Eudromaeosaur skulls are also relatively solid in comparison to their primitive coelurosaur ancestors (i.e. they had smaller paranasal sinuses). In particular, the skull pneumaticity of oviraptorosaurs, which share a common ancestor with both birds and eudromaeosaurs is much higher than in any eudromaeosaurs. A 2021 survey of the premaxillae, maxillae, nasals, lacrimals, and jugals of several eudromaeosaurs was conducted in an attempt to reconstruct the ancestral condition of facial pneumaticity for coelurosaurs. The pneumatic elements of all five bones show a marked decline from basal coelurosaurs to derived paravians, with eudromaeosaurs completely lacking pneumatic spaces in their premaxillae. The reason for this evolutionary trend is unclear.[22]

Compared to other clades of theropods, eudromaeosaurs exhibited relatively little variation in the dimensions of their skulls. Some researchers have suggested that this is a result of their relatively conservative ecology. According to this estimation, most eudromaeosaurs are hypercarnivores of prey similar in size or larger than themselves, which imposes constraints on the functionally effective range of skull shapes. In the same analysis, it is suggested that the earliest eudromaeosaurs had skulls more like velociraptorines than dromaeosaurines or saurornitholestines due to the morphological similarity of troodontid skulls (believed to be the closest relatives of dromaeosaurids).[23]

The teeth of dromaeosaurines differed from those of velociraptorines in having a low DSDI ratio (their teeth had equally-sized serrations) on both the posterior and on the anterior edges. By contrast, velociraptorines often have larger serrations on the posterior side of the tooth, than the anterior, or no serrations on the anterior side at all.[5][15]

Integument

See also: Feathered dinosaur and List of non-avian dinosaur species preserved with evidence of feathers
The ulna of Dineobellator showing the position of the quill knobs

Throughout the 1990s and early 2000s, a variety of fossil discoveries from the Yixian and Jiufotang formations demonstrated that many small microraptorian dromaeosaurids were covered in coats of feathers and possessed fully asymmetrical pennaceous wing feathers. Among such discoveries were the small dromaeosaurs Sinornithosaurus,[24][25] Microraptor,[26] Changyuraptor,[27] Zhenyuanlong,[28] Wulong,[29] Daurlong,[30] and at least one unnamed taxon (specimen IVPP V13476).[31][32]

In 2007 paleontologists studied the ulna of a specimen of Velociraptor and discovered small bumps on the surface, known as quill knobs. The same feature is present in some bird bones, and represents the attachment point for strong secondary wing feathers. This finding provided the first direct evidence that eudromaeosaurs had feathers.[33][33] In the years since, similar indirect evidence of feathers in true eudromaeosaurs has been found for the genera Dakotaraptor[34] and Dineobellator.[35]

Today, it is generally believed that most, if not all coelurosaurs had a coat of filamentous feathers. Based on the available evidence it is likely that all paravians and oviraptorosaurs (and possibly ornithomimosaurs) had pennaceous wing feathers on their arms.[36]

Feet and claws

A reconstruction of the leg musculature of Deinonychus, emblematic of the condition in eudromaeosaurs

The leg proportions of eudromaeosaurs differed considerably from other maniraptorans and also from the closely-related microraptorian dromaeosaurids. Most of these taxa possessed short femora with long tibiae and metatarsals, which are generally accepted to have been adaptations for cursoriality. Conversely, eudromaeosaurs had long femora and tibiae but relatively short metatarsals. The exact reasons for these adaptations are not fully understood, but some authors have suggested that this is an adaptation to improve the strength and robustness of the legs for the purpose of using their feet during predation.[37]

Aside from their generally larger size when compared to earlier-diverging dromaeosaurids, eudromaeosaurs are characterized by several features of the foot. First, differences existed in the positions of the grooves that anchored blood vessels and keratin sheathes of the toe claws. In primitive dromaeosaurids like Hesperonychus, these grooves ran parallel to each other on either side of the claw along its length. In eudromaeosaurs, the grooves were asymmetrical, with the inner one split into two distinct grooves and elevated toward the top of the claw, while the single outer groove remained positioned at the midline.[6]

The second distinguishing characteristic of eudromaeosaurs is an expanded and enlarged "heel" on the last bone in the second toe (phalanx), which bore the enlarged, sickle-like toe claw. Finally, the first bone of the second toe also possessed an enlarged expansion at the joint, another adaptation relating to the unusually enlarged claw, and which helped the animal hold the claw high off the ground. Also unlike their more basal relatives, the sickle claw of eudromaeosaurs was sharper and more blade-like. In unenlagiines and microraptorines, the claw is broader at its base.[6]

Tail

The tail of Dromaeosaurus, showing the caudotheca

Most eudromaeosaurs for which the caudal vertebrae are known have more such vertebrae than their maniraptoran relatives. They generally had more than 30 caudal vertebrae, with at least the nine most anterior vertebrae bearing transverse processes.[1] They also possessed structures called "caudotheca", which are highly elongated prezygapophyses and chevrons.[38] These elongations of the bone encase the caudal vertebrae and form a rod-like structure. In some derived dromaeosaurines — namely Achillobator, Utahraptor, and Yurgovuchia — the caudotheca are reduced in length in comparison with related taxa.[1]

The tails of non-avian paravians, including eudromaeosaurs, are composed of vertebrae of two different shapes. The anterior caudal vertebrae are very typical of the shape of other coelurosaurs. The posterior caudal vertebrae, on the other hand, are marked by a loss of their transverse processes, a reduction in their neural spines, and the haemal arches take the shape of an upside-down 'T' in cross-section. The centra of the posterior caudals are also highly elongated. Unlike most other coelurosaurs, this transition in the shape of the vertebrae is abrupt, rather than having a gradual change in morphology. This condition is called a "Type-2 Transition", to contrast with the similarly bifurcated, but morphologically distinct, "Type-1 Transition" seen in ornithomimosaurs.[1]

Paleobiology and behavior

Skull function

Finite element analysis results testing the strain on the skulls of several eudromaeosaurs (A-E)

Eudromaeosaur skulls have been characterized in the scientific literature as being relatively conservative in comparison to their maniraptoran relatives. The skulls had few pneumatic spaces, especially in comparison to birds and oviraptorosaurs[22] and retained the slightly tapered rostrum of primitive tetanurans without any significant changes in length or depth.[23] This is largely a result of the dietary ecology of eudromaeosaurs, which took on a traditionally carnivorous role in contrast to all other maniraptorans, which were either herbivorous or omnivorous.[39]

A 2024 paper studying eudromaeosaur skulls performed several analyses, including finite element analysis (FEA) in an attempt to infer their physical properties. Their results supported the hypothesis that Deinonychus was adapted to hunt large prey (especially the sympatric ornithopod Tenontosaurus) due to a suggested relatively high bite force and slow bite speed. The same analysis recovered a relatively high mechanical advantage for the skull of Dromaeosaurus and a high resistance to bending, both of which are associated with tackling large vertebrate prey.[23] This is consistent with the loss of pneumatic elements in the facial bones of eudromaeosaurs, which have been suggested to be adaptations for subduing and feeding on large prey.[22]

In velociraptorine taxa, the structure of the fenestrae in the skull are adapted for dispersing the strain of any force exerted on it throughout the skull, which leads to less strain on each of the individual points of leverage on the skull. Similarities between velociraptorines and troodontids led the authors to suggest that a velociraptorine skull condition may be ancestral to eudromaeosaurs.[23] Other researchers have suggested that the fenestration of the velociraptorine skull is a derived condition resulting from the expansion of cranial sinuses.[21] Another study of theropod bite forces suggested that Dromaeosaurus and Saurornitholestes were better adapted to crushing the bones of relatively small prey.[40]

Teeth and diet

See also: The Fighting Dinosaurs and Dinosaur diet and feeding
Two eudromaeosaur teeth: Zapsalis (left) and Velociraptor (right)
  • Morphological disparity in teeth[41]
  • Gnawing behavior[42]
  • Juvenile ceratopsian bite marks[43]
  • Yurgovuchia found with ankylosaur and iguanodont remains[1]
  • Azhdarchid scavenging[44]
  • Cedar mountain niche partitioning[45]
  • Fighting dinosaurs[46]
  • Actual feeding process[47]
  • Diet vs unenlagiines[48]
  • Digging predation[49]

Eudromaeosaurs are presumed to have all been hypercarnivores. However, their considerable variation in size and distribution throughout the Cretaceous implies that there was likely a great variety in the composition of their prey.

Possible modes of eudromaeosaur predation
  • Hunting much smaller animals
    Hunting much smaller animals
  • Restraining and disemboweling similarly-sized animals
    Restraining and disemboweling similarly-sized animals
  • Individual combat with larger or similarly-sized animals
    Individual combat with larger or similarly-sized animals
  • Forming groups to hunt larger animals
    Forming groups to hunt larger animals

Metabolism and thermoregulation

A CT scan of a Velociraptor skull showing the nasal cavity in yellow

All eudromaeosaurs (and coelurosaurs in general) are presumed to have been endotherms. The presence of feathers has been suggested to have been an adaptation initially developed for insulation, which would be of limited use to fully ectothermic organisms. Therefore, the presence of feathers can probably be used to indirectly infer the presence of endothermy.[36] However, eudromaeosaurs were likely not as efficient in their thermoregulation as modern mammals or birds and were believed to have possessed a lower average metabolic rate than these modern animals.[50]

In a 2023 study of the skull anatomy of several extinct and extant theropods used computed tomography to model the volumes of their nasal cavities and compare them to the volumes of the skulls as a whole. These were subjected to a regression analysis which recovered a relationship between these two volumes and the efficiency of the nasal passage as a thermoregulatory apparatus. Under this analysis, the eudromaeosaur tested, Velociraptor, was suggested to have been capable of much less efficient nasal thermoregulation than modern birds. This is consistent with earlier suggestions that dromaeosaurs had a lower metabolic rate than modern birds.[51]

Arm and wing function

Diagram of the arms of several dinosaurs including maniraptorans (left); semilunate carpal of Linheraptor (right)

Like most paravians, eudromaeosaurs possessed a highly derived semilunate carpal formed by the co-ossification of the three distal-most carpal bones. This condition allows for the hand to be folded flat against the ulna in order to hold their wings close to the body.[52] The resting position of the elbow would likely have been an extremely acute angle for eudromaeosaurs, with the wings held close to the body, but not fully folded in the manner of modern birds.[53]

The mobility capabilities of eudromaeosaur arms were reconstructed in a 2006 analysis which used both direct observation of skeletal muscle correlates and phylogenetic inferences based on extant taxa. Among modern birds, tinamous and neognaths are believed to have had shoulder anatomy most similar to eudromaeosaurs, whereas most ratites are believed to have secondarily lost a significant ammount of shoulder mobility. The skeletons of several eudromaeosaurs, including Velociraptor and Saurornitholestes, were compared and preserved many elements homologous with the arm musculature of both Sphenosuchus and Archaeopteryx, implying a relatively conservative archosaur shoulder musculature. One major difference found was that Dromaeosaurus and some similar taxa possibly possessed relatively strong biceps compared to other maniraptorans of a similar size.[54]

A depiction of a dromaeosaur using its wings to stabilize itself while feeding on live prey

The arm function of Deinonychus and Saurornitholestes has also been studied in detail in order to infer the estimated total range of motion for the arms. The remains of these genera were modeled, articulated, and measured based on the morphology of the articular surfaces of the limb bones. Several functional hypotheses were suggested and the results of the modeling were used to falsify these hypotheses. It was inferred from this analysis that it was impossible for eudromaeosaurs to use their hands to dig, scratch themselves, probe small crevices, or carry objects with a single hand. Other functional uses for the arms and hands such as carrying objects with both hands, maintain balance, or bring objects to its mouth to feed could not be falsified. Velociraptor, despite being known from very complete remains, has not had its forelimb mobility extensively studied because most of the specimens are preserved fully articulated and have not been fully removed from the rocks in which they were found.[55]

Claw function

See also: Claw function in Dromaeosauridae
A diagram showing possible functions of the sickle-claw in eudromaeosaurs
  • Claw biomechanics[57]
  • Muscular modeling of claws[58]
  • Ontogenetic dietary shift in Deinonychus[59]

Locomotion

See also: Wing-assisted incline running
  • Walking cycle reconstruction[60]
  • Comparative dromaeosaurid locomotion[61]
  • Purpose of the claws[62]

Eyes and senses

See also: Dinosaur vision and Dinosaur senses

Reproduction

A life reconstruction of Deinonychus brooding with the aid of its wings
  • Possible Deinonychus egg[67]
  • Coloration of eggs[68]
  • Description of a dromaeosaur ootaxon[69]

Growth and ontogeny

Ontogenetic size of Utahraptor
  • Ontogenetic variation in Deinonychus[70]
  • Baby dromaeosaur from Prince Creek[71]
  • Growth patterns[72]
  • Review of Pennaraptora[73]

Classification

Technical diagnosis

The original definition of Eudromaeosauria was a node-based definition. It was defined as the least-inclusive clade containing Utahraptor ostrommaysi, Velociraptor mongoliensis, Deinonychus antirrhopus, and Saurornitholestes langstoni. The apomorphic features of the group were left unresolved at the time of its naming.[6]

In 2012, Alan Turner, Mark Norell, and Peter Makovicky published a review of paravian systematics, which included a list of potential apomorphic characteristics for the group. These included a posteriorly-extending process of the premaxilla separating the maxilla from the nasal bone, a sharply demarcated process on the frontal bone along the orbital margin, a notch on the edge of the frontal near the lacrimal suture, a rounded internal mandibular fenestra, a shallow prootic process on the lateral side of the braincase, the lack of a carotid process on the posterior cervical vertebrae, highly elongated centra in the dorsal vertebrae, and a shortened acromio process of the scapula that does not project anteriorly to the coracoids.[5]

Mark Powers and several colleagues, including Alan Turner, published a second review of the literature in 2021 in relation to eudromaeosaurs specifically. They recovered a monophyletic Eudromaeosauria with several synapomorphies. These included a frontal that is "L"-shaped in dorsal view, a short coracoid, and second metatarsal much shorter than the four metatarsal. They also recovered some more weakly-supported synapomorphies including a paroccipital process that is dorsally twisted, short and relatively massive posterior dorsal vertebrae, and coracoids that are weakly flexed.[74]

Relationships

The skulls of several velociraptorine eudromaeosaurs compared side-by-side

One of the primary phylogenetic matrices in the scientific literature is the so-called "TWiG Matrix" from the Theropod Working Group. This matrix was first published on by Steven Brusatte and colleagues in 2014 in a comprehensive analysis of coelurosaur phylogeny. This matrix included 150 taxa coded for 853 anatomical characters.[75] This matrix has been elaborated upon with the addition of new taxa by several authors, and it remains one of the foremost datasets in modern theropod systematics.[76][77][78][79] A cladogram showing the affinities of Eudromaeosauria within Paraves based on the TWiG Matrix from Napoli and colleagues (2021) is shown below.[76]

Paraves

This classification scheme is the most conventional and widely used, but it is not universally accepted by researchers. There are several competing hypotheses regarding the interrelationships of paravian dinosaurs including those posed by Andrea Cau and colleagues in 2017,[77] Scott Hartman and colleagues in 2019,[80] and Matías Motta and colleagues in 2020.[81]

Subgroups

Dromaeosaurus albertensis (cast)
Saurornitholestes langstoni (MOR 660R)
Velociraptor mongoliensis (MPC-D 100/54)

Eudromaeosauria is divided into three major subgroups. The composition of these groups is not universally agreed upon, but there is consensus on the classification of a few key taxa. Most phylogenetic analyses recover these three groups with varying members and varying degrees of confidence.

According to Turner and colleagues in 2012, technical diagnoses for the first subfamily of eudromaeosaurs, the Dromaeosaurinae, can be established based on several synapomorphies. These include fully serrated teeth; vertically oriented pubis; pubic boot (or end) projecting anteriorly and posteriorly; the jugal process of the maxilla, in a ventral view to the external antorbital fenestra, is dorsoventrally wide. This subfamily includes the eponymous Dromaeosaurus and all of its closest relatives.[5]

When erected by Barsbold in 1983, the second subfamily of eudromaeosaurs — Velociraptorinae — was conceived as a group containing Velociraptor and supposed closely related species.[82] It was not until 1998 that this group was defined as a clade by Paul Sereno. Sereno defined the group as all dromaeosaurids more closely related to Velociraptor than to Dromaeosaurus.[83] While several studies have since recovered a group of dromaeosaurids closely related to Velociraptor, they vary widely regarding which species are actually velociraptorines and which are either more basal or closer to Dromaeosaurus.

In 2005, Novas and Pol found a distinct velociraptorine clade close to the traditional view, which included Velociraptor, Deinonychus, and material that was later named Tsaagan. The analysis conducted by Turner and colleagues also supported a traditional, monophyletic of Velociraptorinae.[5] However, some studies found a very different group of dromaeosaurids in velociraptorinae, such as Longrich and Currie (2009), which found Deinonychus to be a non-velociraptorine, non-dromaeosaurine eudromaeosaur, and Saurornitholestes to be a member of a more basal group they named Saurornitholestinae.[6] A larger analysis in 2013 found some traditional velociraptorines, such as Tsaagan, to be more basal than Velociraptor, while others to be more closely related to Dromaeosaurus, making them dromaeosaurines. This study found Balaur, previously found to be a velociraptorine by most analyses, to be an avialan instead.[84]

Saurornitholestinae is the third, and most recently named, subfamily of Eudromaeosauria. The saurornitholestines are generally found to include three monotypic genera: Atrociraptor marshalli, Bambiraptor feinbergi, and Saurornitholestes langstoni. All are medium-sized dromaeosaurs from the Late Cretaceous of western North America. The group was originally recognized by Longrich and Currie as the sister taxon to a clade formed by the Dromaeosaurinae and Velociraptorinae.[6] However, not all phylogenetic analyses recover this group with the same proposed genera.[5][1][80]

Occasionally, phylogenetic analyses will produce results that do not conform to the traditional topology that includes only three sub-clades. In their description of Acheroraptor in 2013, Evans and colleagues recovered the genera Atrociraptor and Deinonychus in a clade more derived than Saurornitholestinae, but more basal than either Dromaeosaurinae or Velociraptorinae.[85] In the 2020 description of Dineobellator, Jasinski and colleagues recovered the genera Utahraptor, Achillobator, and Adasaurus in a clade that was the sister-taxon of Velociraptorinae.[35] A similar result to Jasinski and colleagues was recovered by Hartman and colleagues a year earlier.[80] None of these aberrant clades have received strong support from subsequent analyses.[76][78][86][87]

Additionally, in some analyses, one or more of the subfamilies are recovered as containing only their eponymous genus. Under these results, the subfamily is functionally indistinguishable from the genus.[5][88]

Taxonomic uncertainty

The precise nature of the relationship between the three main subgroups of eudromaeosaurs is not known with confidence. Saurornitholestines are sometimes regarded as the most early-diverging eudromaeosaurs, while others find them to be closely related to dromaeosaurines. Several analyses have recovered incongruent results. Below is a summary of the three possible classification schemes based on the findings of different analyses.

Choiniere et al. (2014)[89]

Eudrom.

Dromaeosaurinae

Saurornitholestinae

Velociraptorinae

Napoli et al. (2021)[76]

Eudrom.

Saurornitholestinae

Dromaeosaurinae

Velociraptorinae

Czepiński (2022)[87]

Eudrom.

Velociraptorinae

Dromaeosaurinae

Saurornitholestinae

The internal composition of the three eudromaeosaur subfamilies is even more contentious than the relationships betweem the subfamilies themselves. Multiple different competing phylogenetic matrices have been proposed in the literature under various methodological frameworks. Besides the TWiG Matrix (mentioned above) there is the matrix compiled by Mark Powers,[87] the one compiled by Scott Hartman and colleagues,[80] Jonah Choiniere's matrix,[89] Lindsay Zanno's matrix,[90] Andrea Cau's matrix,[86] and the matrix published by Phil Currie and David Evans.[35] Some researchers have combined one or more of these matrices to produce additional novel results.[35][91] The list below includes a summary of the possible classifications for each dromaeosaur genus that have been thus far suggested by various researchers.

Possible Affinities of Eudromaeosaur Genera

Unambiguous Eudromaeosaurs

Genus Suggested classifications
Acheroraptor Originally described as a velociraptorine,[85] subsequently recovered as a saurornitholestine[74]
Achillobator Generally believed to be a dromaeosaurine,[76][77] has been recovered as being closely related to, but outside of, velociraptorines[35]
Adasaurus Originally described as a dromaeosaurine,[82] generally believed to be a velociraptorine,[76][78][35] but has been subsequently recovered as a dromaeosaurine,[92] a saurornitholestine,[90] or as a basal member of eudromaeosauria[35][87][93]
Atrociraptor Originally described as a velociraptorine,[94] subsequently recovered as a dromaeosaurine,[88] a saurornitholestine,[91][74] or as being outside all three subfamilies[85]
Bambiraptor Either a saurornitholestine,[6] a junior synonym of Saurornitholestes,[95] or a basal member of eudromaeosauria,[35][91][76][96] has also been found as a velociraptorine[86]
Boreonykus Originally described as a velociraptorine,[97] has also been recovered as a dromaeosaurine[35][78]
Deinonychus Variously found as a dromaeosaurine,[88][74] a velociraptorine,[76][78][21] a saurornitholestine,[91][87] or being outside of all three groups[85][91]
Dineobellator Originally described as a velociraptorine,[35] which has been supported,[74][78] may be outside of all three major subfamilies[91]
Dromaeosaurus Must belong to Dromaeosaurinae by definition[5]
Itemirus Originally assigned to its own family ("Itemiridae") outside of dromaeosauridae,[98] later recovered as a dromaeosaurine[99] or possibly a velociraptorine[6]
Kansaignathus Early-diverging velociraptorine[78][100]
Kuru Velociraptorine very closely related to Velociraptor[76][78][87]
Luanchuanraptor Described as a velociraptorine[101]
Linheraptor Originally described as a basal eudromaeosaur closely related to Tsaagan,[102] has also been recovered as a velociraptorine[76][21][78][87] and a dromaeosaurine[80]
Saurornitholestes Must belong to Saurornitholestinae by definition[5]
Shri Generally accepted to be a velociraptorine[76][87]
Tsaagan Originally described as a velociraptorine,[103] which has been supported by subsequent analyses,[21][76][78] has also been recovered as a dromaeosaurine[80][90] or as being outside all three subfamilies,[88] generally agreed to be a close relative of Linheraptor[102][76]
Utahraptor Generally believed to be a dromaeosaurine,[88][76][78][1][21][5] has been suggested to be a velociraptorine[96] or to be outside all three subfamilies[85]
Velociraptor Must belong to Velociraptorinae by definition[5]
Yurgovuchia Originally described as a dromaeosaurine,[1] may be a basal eudromaeosaur[80]

Possible Eudromaeosaurs

Genus Suggested classifications
Balaur Described as a velociraptorine,[76] has been recovered as a dromaeosaurine, may be a stem-avialan[84][80]
Dakotaraptor Believed by some to be a chimera,[104][35][86] originally described as a dromaeosaurine,[88] subsequently found as a possible unenlagiine[80]
Dromaeosauroides Potentially dubious genus, only known from teeth, originally described as a dromaeosaurine,[105] subsequently recovered as an indeterminate dromaeosaurid[106]
Hesperonychus Originally described as a microraptorian,[6] but may be an avialan,[80] a eudromaeosaur, or some other kind of dromaeosaurid[35]
Nuthetes Potentially dubious genus, only known from teeth, may or may not be a velociraptorine[107][108]
Ornithodesmus Potentially dubious genus, may be an unenlagiine[80] or a eudromaeosaur[109]
Pyroraptor May be a dromaeosaurine or an indeterminate eudromaeosaur,[110] has been recovered as an unenlagiine[80]
Tianyuraptor Generally believed to be a microraptorian,[93] sometimes recovered as a eudroameosaur[93] or an unenlagiine[21]
Ulughbegsaurus Originally described as a carcharodontosaur, but may be a large eudromaeosaur[20]
Variraptor May be a dromaeosaurine, an indeterminate eudromaeosaur, an unenlagiine,[110] or a microraptorian[80]
Vectiraptor Tentatively described as a eudromaeosaur[110]
Yixianosaurus Originally described as an indeterminate maniraptoran,[111] but has since been recovered as an anchiornithid,[77] a scansoriopterygid,[112] as a basal eudromaeosaur,[80] or some other kind of stem-paravian[113]
Zapsalis Potentially dubious genus, only known from teeth, possible junior synonym of Saurornitholestes[96]

Evolutionary history

Evolutionary origin

See also: Origin of birds
Nuthetes (center), which is the most ancient eudromaeosaur to be named thus far

Dromaeosaurids presumably originated in the Middle Jurassic, along with their relatives the troodontids and avialans.[114] This is inferred from their phylogeny, but no dromaeosaur fossils have yet been discovered from this timeframe. This has been interpreted as a taphonomic bias as a result of the presumably fragile skeletons of the earliest dromaeosaurs.[115] Eudromaeosaurs, as derived members of Dromaeosauridae, likely evolved slightly later in the Jurassic Period, or possibly even at the beginning of the Cretaceous.[116]

Evidence of their presence, pending the eventual discovery of body fossils, is limited to fossilized teeth. These teeth, which may or may not be attributable to velociraptorine eudromaeosaurs were discovered in the Langenberg Quarry in Lower Saxony, Germany, which is estimated to be Kimmeridgian in age. Teeth of a similar morphology have also been discovered from the roughly contemporaneous Alcobaça Formation of Portugal. If these teeth belong to eudromaeosaurs, then they may suggest a European origin of the group.[3] Isolated teeth that may belong to eudromaeosaurs have also been discovered in Ethiopia. These teeth date to the Tithonian stage, of the Late Jurassic period. What implications this may have for the evolutionary history of the group are not clear.[117]

The next fossil evidence of eudromaeosaurs possibly comes from the beginning of the Early Cretaceous. Teeth from the Berriasian-aged Lulworth Formation of England were found and named "Megalosaurus destructor" in the 19th-century. These teeth have since been reassigned to the genus Nuthetes, which has been suggested to be a eudromaeosaur. However, this is not universally accepted, and some researchers have suggested that these teeth belong to tyrannosauroids.[107] The similarly-aged Jydegaard Formation of Denmark has also yielded the tooth taxon Dromaeosauroides, which may have been a dromaeosaurine eudromaeosaur,[118] although some authors consider it to be dubious or an indeterminate dromaeosaurid.[106]

The earliest definitive eudromaeosaurs are known from the Valanginian-aged Yellow Cat Member of the Cedar Mountain Formation in Utah. These genera, Utahraptor and Yurgovuchia, are typically assigned to dromaeosaurinae, and may suggest a North American origin of dromaeosaurines, or even eudromaeosaurs as a whole.[1] Alternatively, some taxa from the Cedar Mountain Formation have been suggested to descend from Asian ancestors, and there may have been a land connection via Beringia between Asia and North America.[119]

Diversification and dispersal

See also: Biogeography of Paravian Dinosaurs
Itemirus from the Turonian of Uzbekistan
Velociraptor from the Campanian of Mongolia

The suggested Late Jurassic or Early Cretaceous origin of eudromaeosaurs is consistent with the fossil record because known eudromaeosaur fossils have a much narrower geographic distribution than Dromaeosauridae as a whole. Eudromaeosaurs are so-far only known from the Northern Hemisphere, whereas dromaeosaurids as a whole had a cosmopolitan distribution. This distribution suggests that eudroameosaurs evolved after Pangaea split into Laurasia and Gondwana, and they were therefore unable to colonize the Southern Hemisphere.[120]

There is a large gap in the general richness of terrestrial fossils in North America during the middle of the Cretaceous Period. The only eudromaeosaur genus from the Albian or Aptian (a roughly 20 million-year-long period) is Deinonychus, which is known from the Antlers and Cloverly formations throughout the western United States.[121] At some point during this gap in the fossil record, eudromaeosaurs dispersed from their ancestral home in either Europe or North America and colonized Asia.[78][21] Cenomanian and Turonian deposits have yielded several eudromaeosaurs of varying affinities including Achillobator, Itemirus, and a large unnamed taxon from the Bissekty Formation.[20]

Velociraptorines appear for the first time in the Santonian of Kyrgyzstan (unless Deinonychus is a velociraptorine) with the taxon Kansaignathus from the Yalovach Formation. The bulk of known velociraptorine diversity would thereafter be found in Asia, and it would include the famous Velociraptor as well as taxa like Tsaagan, Kuru, and Adasaurus.[78][100] Some North American taxa (Acheroraptor and Dineobellator) have also been suggested to be velociraptorines, which would indicate a more complex pattern of dispersal for this clade.[78][85]

Eudromaeosaurs may have also colonized Europe during the Cretaceous. The taxa Balaur, Variraptor, and Pyroraptor have all been suggested to be eudromaeosaurs, and they are each known from the Late Cretaceous of Europe.[122][123] North America appears to have been the only continent on which saurornitholestines lived. Unambiguous members of this group are only known from the Campanian and Maastrichtian of western North America.[96] Dromaeosaur teeth are also known from the Late Cretaceous of Appalachia, although it is not known if these animals arrived before or after the Western Interior Seaway split Appalachia from Laramidia.[124]

Extinction

See also: Cretaceous–Paleogene extinction event, Cretaceous–Paleogene boundary, and Chicxulub crater
Dineobellator from the Maastrichtian of New Mexico, one of the last surviving eudromaeosaurs

Eudromaeosaurs were among the last of the non-avian dinosaurs to persist until the end of the Cretaceous Period. Most eudromaeosaur genera are known from the Campanian and the Maastrichtian, the two stages at the end of the Cretaceous. Several eudromaeosaurs would have lived to see the asteroid impact at the very end of the Cretaceous which led to their extinction alongside all other non-avian dinosaurs.[125]

Several eudromaeosaurs are known from the Maastrichtian of Laramidia. These included Acheroraptor and the possible chimera Dakotaraptor from the Hell Creek Formation[88] and Dineobellator from the Ojo Alamo Formation.[35] The taxon Luanchuanraptor was discovered in the terminal Qiupa Formation of central China.[101] Indeterminate eudromaeosaur remains have also been found at the Udurchukan, Scollard, and Javelina formations. Other localities dated to the very end of the Cretaceous in South America, Africa, and Antarctica have not yielded eudromaeosuar fossils as of yet.[125]

The exact trajectory of non-avian dinosaur diversity at the end of the Cretaceous is not confidently known. Some researchers have suggested that the diversity of dinosaurs was declining leading up to the Chixulub Impact, but this has been met with resistance by other researchers.[126][127][128] The relative rarity of dromaeosaurid remains make it difficult to assess if they were increasing or decreasing in diversity, if either, near the end of the Cretaceous.[115]

It is possible that some individual eudromaeosaurs (or other small non-avian dinosaurs) survived the immediate aftermath of the asteroid impact, but they likely would have been deprived of food. Herbivorous dinosaurs would have found plant material scarce, and carnivores would therefore have quickly found prey in short supply and starved to death. Even if they survived all subsequent environmental disasters and the ecological collapse, any survivors would have likely been too few in number to produce a viable population, resulting in their inevitable extinction.[129]

Paleoecology

  • Velociraptor endocranium[130]
  • Ecology of mesopredators in Aguja[131]
  • Prince Creek teeth and ecology[132]

See also

References

  1. ^ a b c d e f g h i Senter, Phil; Kirkland, James I.; Deblieux, Donald D.; Madsen, Scott; Toth, Natalie (2012). "New Dromaeosaurids (Dinosauria: Theropoda) from the Lower Cretaceous of Utah, and the Evolution of the Dromaeosaurid Tail". PLOS ONE. 7 (5): e36790. Bibcode:2012PLoSO...736790S. doi:10.1371/journal.pone.0036790. PMC 3352940. PMID 22615813.
  2. ^ Sweetman S.C. (2004). "The first record of velociraptorine dinosaurs (Saurischia, Theropoda) from the Wealden (Early Cretaceous, Barremian) of southern England" (PDF). Cretaceous Research. 25 (3): 353–364. doi:10.1016/j.cretres.2004.01.004.
  3. ^ a b Van der Lubbe, T.; Richter, U.; Knotschke, N. (2009). "Velociraptorine dromaeosaurid teeth from the Kimmeridgian (Late Jurassic) of Germany" (PDF). Acta Palaeontologica Polonica. 54 (3): 401–408. doi:10.4202/app.2008.0007.
  4. ^ Matthew, W. D.; Brown, B. (1922). "The family Deinodontidae, with notice of a new genus from the Cretaceous of Alberta". Bulletin of the American Museum of Natural History. 46: 367–385. hdl:2246/1300.
  5. ^ a b c d e f g h i j k Turner, A.H.; Makovicky, P.J.; Norell, M.A. (2012). "A Review of Dromaeosaurid Systematics and Paravian Phylogeny". Bulletin of the American Museum of Natural History. 2012 (371): 1–206. doi:10.1206/748.1. hdl:2246/6352. S2CID 83572446. Cite error: The named reference "Turner2012" was defined multiple times with different content (see the help page).
  6. ^ a b c d e f g h i Longrich, N.R.; Currie, P.J. (2009). "A microraptorine (Dinosauria–Dromaeosauridae) from the Late Cretaceous of North America". PNAS. 106 (13): 5002–7. Bibcode:2009PNAS..106.5002L. doi:10.1073/pnas.0811664106. PMC 2664043. PMID 19289829.
  7. ^ Turner, A.S.; Hwang, S.H.; Norell, M.A. (2007). "A small derived theropod from Öösh, Early Cretaceous, Baykhangor Mongolia" (PDF). American Museum Novitates (3557): 1–27. doi:10.1206/0003-0082(2007)3557[1:ASDTFS]2.0.CO;2. hdl:2246/5845. S2CID 31096081. Archived from the original (PDF) on 2009-03-26. Retrieved 2007-03-29.
  8. ^ "†Deinonychus antirrhopus, Ostrom 1969 (maniraptoran)". The Paleobiology Database. Total: 35 collections each including a single occurrence
  9. ^ "†Utahraptor ostrommaysi, Kirkland et al. 1993 (maniraptoran)". The Paleobiology Database. Total: 2 collections each including a single occurrence
  10. ^ Williams, Carter (February 25, 2021). "Several more Utahraptor fossils discovered from 136M-year-old block 1st found in Utah". KSL.com. Deseret Digital Media. Archived from the original on February 27, 2021.
  11. ^ "†Saurornitholestes langstoni, Sues 1978 (maniraptoran)". The Paleobiology Database. Total: 76 collections including 78 occurrences
  12. ^ "†Velociraptor mongoliensis Osborn 1924 (maniraptoran)". The Paleobiology Database. Total: 10 collections each including a single occurrence
  13. ^ "†Dromaeosaurus albertensis Matthew and Brown 1922 (maniraptoran)". The Paleobiology Database. Total: 20 collections each including a single occurrence
  14. ^ Benson, Roger B. J.; Campione, Nicolás E.; Carrano, Matthew T.; Mannion, Philip D.; Sullivan, Corwin; Upchurch, Paul; Evans, David C. (2014). "Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage". PLOS Biology. 12 (5): e1001853. doi:10.1371/journal.pbio.1001853. PMC 4011683. PMID 24802911.
  15. ^ a b c Holtz, T.R.; Rey, L.V. (2007). Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages. Random House. ISBN 9780375824197. Genus List for Holtz 2012 Weight Information
  16. ^ a b Molina-Pérez, Rubén; Larramendi, Asier (2019). Dinosaur Facts and Figures: The Theropods and Other Dinosauriformes. Translated by Connolly, David; Ramírez Cruz, Gonzalo Ángel. Illustrated by Andrey Atuchin and Sante Mazzei. Princeton University Press. ISBN 978-0691180311.
  17. ^ Perle, A.; Norell, M.A.; Clark, J. (1999). "A new maniraptoran Theropod−Achillobator giganticus (Dromaeosauridae)−from the Upper Cretaceous of Burkhant, Mongolia". Contributions from the Geology and Mineralogy Chair, National Museum of Mongolia (101): 1–105. OCLC 69865262.
  18. ^ Kirkland, J. I.; Burge, D.; Gaston, R. (1993). "A large dromaeosaurid (Theropoda) from the Lower Cretaceous of Eastern Utah". Hunteria. 2 (10): 1–16.
  19. ^ Naish, D. Hutt, and Martill, D.M. (2001). "Saurischian dinosaurs: theropods." in Martill, D.M. and Naish, D. (eds). Dinosaurs of the Isle of Wight. The Palaeontological Association, Field Guides to Fossils. 10, 242–309.
  20. ^ a b c Sues, Hans-Dieter; Averianov, Alexander; Britt, Brooks B. (2022-12-22). "A giant dromaeosaurid theropod from the Upper Cretaceous (Turonian) Bissekty Formation of Uzbekistan and the status of Ulughbegsaurus uzbekistanensis". Geological Magazine. 160 (2): 355–360. doi:10.1017/S0016756822000954. ISSN 0016-7568.
  21. ^ a b c d e f g h i Powers, Mark James; Sullivan, Corwin; Currie, Philip John (2020). "Re-examining ratio based premaxillary and maxillary characters in Eudromaeosauria (Dinosauria: Theropoda): Divergent trends in snout morphology between Asian and North American taxa". Palaeogeography, Palaeoclimatology, Palaeoecology. 547. Bibcode:2020PPP...54709704P. doi:10.1016/j.palaeo.2020.109704.
  22. ^ a b c Brownstein, Chase Doran (2021). "Dromaeosaurid crania demonstrate the progressive loss of facial pneumaticity in coelurosaurian dinosaurs". Zoological Journal of the Linnean Society. 191: 87–112. doi:10.1093/zoolinnean/zlaa048.
  23. ^ a b c d Tse, Yuen Ting; Miller, Case Vincent; Pittman, Michael (2024). "Morphological disparity and structural performance of the dromaeosaurid skull informs ecology and evolutionary history". BMC Ecology and Evolution. 24 (1): 39. Bibcode:2024BMCEE..24...39T. doi:10.1186/s12862-024-02222-5. PMC 11020771. PMID 38622512.
  24. ^ Wu, Xiao-Chun; Xu, Xing; Wang, Xiao-Lin (1999). "A dromaeosaurid dinosaur with a filamentous integument from the Yixian Formation of China". Nature. 401 (6750): 262–266. Bibcode:1999Natur.401..262X. doi:10.1038/45769. S2CID 4430574.
  25. ^ Liu, J.; Ji, S.; Tang, F.; Gao, C. (2004). "A new species of dromaeosaurids from the Yixian Formation of western Liaoning". Geological Bulletin of China. 23 (8): 778–783. abstract)
  26. ^ Xu, Xing; Zhou, Zhonghe; Wang, Xiaolin (2000). "The smallest known non-avian theropod dinosaur" (PDF). Nature. 408 (6813): 705–708. Bibcode:2000Natur.408..705X. doi:10.1038/35047056. PMID 11130069. S2CID 4411157. Archived from the original (PDF) on 2008-12-17.
  27. ^ Gang Han; Luis M. Chiappe; Shu-An Ji; Michael Habib; Alan H. Turner; Anusuya Chinsamy; Xueling Liu; Lizhuo Han (2014). "A new raptorial dinosaur with exceptionally long feathering provides insights into dromaeosaurid flight performance". Nature Communications. 5: Article number 4382. Bibcode:2014NatCo...5.4382H. doi:10.1038/ncomms5382. PMID 25025742.
  28. ^ Lü, Junchang; Brusatte, Stephen L. (2015). "A large, short-armed, winged dromaeosaurid (Dinosauria: Theropoda) from the Early Cretaceous of China and its implications for feather evolution". Scientific Reports. 5: 11775. Bibcode:2015NatSR...511775L. doi:10.1038/srep11775. PMC 4504142. PMID 26181289.
  29. ^ Poust, Ashley W.; Gao, Chunling; Varricchio, David J.; Wu, Jianlin; Fengjiao, Zhang (2020). "A new microraptorine theropod from the Jehol Biota and growth in early dromaeosaurids". The Anatomical Record. 303 (4): 963–987. doi:10.1002/ar.24343. PMID 31943887. S2CID 210334980.
  30. ^ Wang, Xuri; Cau, Andrea; Guo, Bin; Ma, Feimin; Qing, Gele; Liu, Yichuan (2022). "Intestinal preservation in a birdlike dinosaur supports conservatism in digestive canal evolution among theropods". Scientific Reports. 12 (1): 19965. doi:10.1038/s41598-022-24602-x. PMC 9675785. PMID 36402874. S2CID 253672525.
  31. ^ Xu, Xing; Zhou, Zhonghe; Wang, Xiaolin; Kuang, Xuewen; Zhang, Fucheng; Du, Xiangke (2003). "Four-winged dinosaurs from China". Nature. 421 (6921): 335–340. Bibcode:2003Natur.421..335X. doi:10.1038/nature01342. ISSN 0028-0836. PMID 12540892. S2CID 1160118.
  32. ^ Xu, Xing; Li, Feng (2016). "A new microraptorine specimen (Theropoda: Dromaeosauridae) with a brief comment on the evolution of compound bones in theropods". Vertebrata PalAsiatica. 54 (4): 269–285.
  33. ^ a b Turner, A.H.; Makovicky, P.J.; Norell, M.A. (2007). "Feather quill knobs in the dinosaur Velociraptor". Science. 317 (5845): 1721. Bibcode:2007Sci...317.1721T. doi:10.1126/science.1145076. PMID 17885130. Cite error: The named reference "turneretal2007b" was defined multiple times with different content (see the help page).
  34. ^ Robert A. DePalma; David A. Burnham; Larry D. Martin; Peter L. Larson; Robert T. Bakker (2015). "The first giant raptor (Theropoda: Dromaeosauridae) from the Hell Creek Formation". Paleontological Contributions. 14: 1–15.
  35. ^ a b c d e f g h i j k l m Jasinski, Steven E.; Sullivan, Robert M.; Dodson, Peter (December 2020). "New Dromaeosaurid Dinosaur (Theropoda, Dromaeosauridae) from New Mexico and Biodiversity of Dromaeosaurids at the end of the Cretaceous". Scientific Reports. 10 (1): 5105. Bibcode:2020NatSR..10.5105J. doi:10.1038/s41598-020-61480-7. PMC 7099077. PMID 32218481.
  36. ^ a b Xu, Xing (2020), Foth, Christian; Rauhut, Oliver W. M. (eds.), "Filamentous Integuments in Nonavialan Theropods and Their Kin: Advances and Future Perspectives for Understanding the Evolution of Feathers", The Evolution of Feathers: From Their Origin to the Present, Fascinating Life Sciences, Cham: Springer International Publishing, pp. 67–78, doi:10.1007/978-3-030-27223-4_5, ISBN 978-3-030-27223-4, S2CID 216384668
  37. ^ Dececchi, T. Alexander; Mloszewska, Aleksandra M.; Holtz, Thomas R.; Habib, Michael B.; Larsson, Hans C. E. (2020). "The fast and the frugal: Divergent locomotory strategies drive limb lengthening in theropod dinosaurs". PLOS ONE. 15 (5): e0223698. Bibcode:2020PLoSO..1523698D. doi:10.1371/journal.pone.0223698. PMC 7220109. PMID 32401793.
  38. ^ Horner, John R.; Woodward, Holly N.; Bailleul, Alida M. (2016). "Mineralized tissues in dinosaurs interpreted as having formed through metaplasia: A preliminary evaluation". Comptes Rendus Palevol. 15 (1–2): 176–196. Bibcode:2016CRPal..15..176H. doi:10.1016/j.crpv.2015.01.006.
  39. ^ Zanno, Lindsay E.; Makovicky, Peter J. (2011). "Herbivorous ecomorphology and specialization patterns in theropod dinosaur evolution". Proceedings of the National Academy of Sciences. 108 (1): 232–237. Bibcode:2011PNAS..108..232Z. doi:10.1073/pnas.1011924108. PMC 3017133. PMID 21173263.
  40. ^ Monfroy, Quentin T. (2017). "Correlation between the size, shape and position of the teeth on the jaws and the bite force in Theropoda". Historical Biology. 29 (8): 1089–1105. doi:10.1080/08912963.2017.1286652.
  41. ^ Larson, Derek W.; Brown, Caleb M.; Evans, David C. (2016). "Dental Disparity and Ecological Stability in Bird-like Dinosaurs prior to the End-Cretaceous Mass Extinction". Current Biology. 26 (10): 1325–1333. doi:10.1016/j.cub.2016.03.039. PMID 27112293.
  42. ^ Brown, Caleb M.; Tanke, Darren H.; Hone, David W.E. (2021). "Rare evidence for 'gnawing-like' behavior in a small-bodied theropod dinosaur". PeerJ. 9: e11557. doi:10.7717/peerj.11557. PMC 8234920. PMID 34221716.
  43. ^ Hone, David W.E.; Tanke, Darren H.; Brown, Caleb M. (2018). "Bite marks on the frill of a juvenile Centrosaurus from the Late Cretaceous Dinosaur Provincial Park Formation, Alberta, Canada". PeerJ. 6: e5748. doi:10.7717/peerj.5748. PMC 6188009. PMID 30345174.
  44. ^ Hone, David; Tsuihiji, Takanobu; Watabe, Mahito; Tsogtbaatr, Khishigjaw (2012). "Pterosaurs as a food source for small dromaeosaurs". Palaeogeography, Palaeoclimatology, Palaeoecology. 331–332: 27–30. doi:10.1016/j.palaeo.2012.02.021.
  45. ^ Frederickson, J. A.; Engel, M. H.; Cifelli, R. L. (2018). "Niche Partitioning in Theropod Dinosaurs: Diet and Habitat Preference in Predators from the Uppermost Cedar Mountain Formation (Utah, U.S.A.)". Scientific Reports. 8: 17872. Bibcode:2018NatSR...817872F. doi:10.1038/s41598-018-35689-6. PMID 30552378.
  46. ^ Carpenter, Kenneth (1998). "Evidence of Predatory Behavior by Carnivorous Dinosaurs" (PDF). GAIA. 15: 135–144. ISSN 0871-5424.
  47. ^ Torices, A.; Wilkinson, R.; Arbour, V.M.; Ruiz-Omeñaca, J.I.; Currie, P.J. (2018). "Puncture-and-Pull Biomechanics in the Teeth of Predatory Coelurosaurian Dinosaurs". Current Biology. 28 (9): 1467–1474. Bibcode:2018CBio...28E1467T. doi:10.1016/j.cub.2018.03.042. PMID 29706515.
  48. ^ Gianechini, Federico A.; Ercoli, Marcos D.; Díaz-Martínez, Ignacio (2020). "Differential locomotor and predatory strategies of Gondwanan and derived Laurasian dromaeosaurids (Dinosauria, Theropoda, Paraves): Inferences from morphometric and comparative anatomical studies". Journal of Anatomy. 236 (5): 772–797. doi:10.1111/joa.13153. PMC 7163733. PMID 32023660.
  49. ^ Simpson, Edward L.; Hilbert-Wolf, Hannah L.; Wizevich, Michael C.; Tindall, Sarah E.; Fasinski, Ben R.; Storm, Lauren P.; Needle, Mattathias D. (2010). "Predatory digging behavior by dinosaurs". Geology. 38 (8): 699–702. Bibcode:2010Geo....38..699S. doi:10.1130/G31019.1.
  50. ^ Paul, Gregory S. (2002). Dinosaurs of the Air: The Evolution and Loss of Flight in Dinosaurs and Birds. Baltimore: Johns Hopkins University Press. ISBN 978-0-8018-6763-7.
  51. ^ Tada, Seishiro; Tsuihiji, Takanobu; Matsumoto, Ryoko; Hanai, Tomoya; Iwami, Yasuko; Tomita, Naoki; Sato, Hideaki; Tsogtbaatar, Khishigjav (2023). "Evolutionary process toward avian-like cephalic thermoregulation system in Theropoda elucidated based on nasal structures". Royal Society Open Science. 10 (4). Bibcode:2023RSOS...1020997T. doi:10.1098/rsos.220997. PMID 37063996.
  52. ^ Xu, Xing; Han, Fenglu; Zhao, Qi (2014). "Homologies and homeotic transformation of the theropod 'semilunate' carpal". Scientific Reports. 4: 6042. Bibcode:2014NatSR...4E6042X. doi:10.1038/srep06042. PMID 25116378.
  53. ^ Senter, Phil; Robins, James H. (2015). "Resting Orientations of Dinosaur Scapulae and Forelimbs: A Numerical Analysis, with Implications for Reconstructions and Museum Mounts". PLOS ONE. 10 (12): e0144036. Bibcode:2015PLoSO..1044036S. doi:10.1371/journal.pone.0144036. PMC 4684415. PMID 26675035.
  54. ^ Jasinoski, Sandra C.; Russell, Anthony P.; Currie, Philip J. (2006). "An integrative phylogenetic and extrapolatory approach to the reconstruction of dromaeosaur (Theropoda: Eumaniraptora) shoulder musculature". Zoological Journal of the Linnean Society. 146 (3): 301–344. doi:10.1111/j.1096-3642.2006.00200.x.
  55. ^ Senter, Phil (2006). "Comparison of forelimb function between Deinonychus and Bambiraptor (Theropoda: Dromaeosauridae)". Journal of Vertebrate Paleontology. 26 (4): 897. doi:10.1671/0272-4634(2006)26[897:COFFBD]2.0.CO;2. ISSN 0272-4634.
  56. ^ Fowler, Denver; Freedman, Elizabeth; Scannella, John; Kambic, Robert (December 14, 2011). "The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds". PLOS ONE. 6 (12): e28964. doi:10.1371/journal.pone.0028964. PMC 3237572. PMID 22194962.
  57. ^ Manning, Phillip L.; Margetts, Lee; Johnson, Mark R.; Withers, Philip J.; Sellers, William I.; Falkingham, Peter L.; Mummery, Paul M.; Barrett, Paul M.; Raymont, David R. (2009). "Biomechanics of Dromaeosaurid Dinosaur Claws: Application of X-Ray Microtomography, Nanoindentation, and Finite Element Analysis". The Anatomical Record. 292 (9): 1397–1405. doi:10.1002/ar.20986. PMID 19711472.
  58. ^ Bishop, Peter J. (2019). "Testing the function of dromaeosaurid (Dinosauria, Theropoda) 'sickle claws' through musculoskeletal modelling and optimization". PeerJ. 7: e7577. doi:10.7717/peerj.7577. PMID 31523517.
  59. ^ Frederickson, J.A.; Engel, M.H.; Cifelli, R.L. (2020). "Ontogenetic dietary shifts in Deinonychus antirrhopus (Theropoda; Dromaeosauridae): Insights into the ecology and social behavior of raptorial dinosaurs through stable isotope analysis". Palaeogeography, Palaeoclimatology, Palaeoecology. 552. Bibcode:2020PPP...55209780F. doi:10.1016/j.palaeo.2020.109780.
  60. ^ Manafzadeh, Armita R.; Gatesy, Stephen M.; Bhullar, Bhart-Anjan S. (2024). "Articular surface interactions distinguish dinosaurian locomotor joint poses". Nature Communications. 15 (1): 854. Bibcode:2024NatCo..15..854M. doi:10.1038/s41467-024-44832-z. PMC 10873393. PMID 38365765.
  61. ^ Gianechini, Federico A.; Ercoli, Marcos D.; Díaz-Martínez, Ignacio (2020). "Differential locomotor and predatory strategies of Gondwanan and derived Laurasian dromaeosaurids (Dinosauria, Theropoda, Paraves): Inferences from morphometric and comparative anatomical studies". Journal of Anatomy. 236 (5): 772–797. doi:10.1111/joa.13153. PMC 7163733. PMID 32023660.
  62. ^ Manning, Phillip L.; Payne, David; Pennicott, John; Barrett, Paul M.; Ennos, Roland A. (2006). "Dinosaur killer claws or climbing crampons?". Biology Letters. 2 (1): 110–112. doi:10.1098/rsbl.2005.0395. PMC 1617199. PMID 17148340.
  63. ^ Schmitz, L.; Motani, R. (14 April 2011). "Nocturnality in Dinosaurs Inferred from Scleral Ring and Orbit Morphology". Science. 332 (6030): 705–708. Bibcode:2011Sci...332..705S. doi:10.1126/science.1200043. PMID 21493820. S2CID 33253407.
  64. ^ Choiniere, Jonah N.; Neenan, James M.; Schmitz, Lars; Ford, David P.; Chapelle, Kimberley E. J.; Balanoff, Amy M.; Sipla, Justin S.; Georgi, Justin A.; Walsh, Stig A.; Norell, Mark A.; Xu, Xing; Clark, James M.; Benson, Roger B. J. (7 May 2021). "Evolution of vision and hearing modalities in theropod dinosaurs". Science. 372 (6542): 610–613. Bibcode:2021Sci...372..610C. doi:10.1126/science.abe7941. ISSN 0036-8075. PMID 33958472. S2CID 233872840.
  65. ^ Zelenitsky, Darla K; Therrien, François; Kobayashi, Yoshitsugu (28 October 2008). "Olfactory acuity in theropods: palaeobiological and evolutionary implications". Proceedings of the Royal Society B: Biological Sciences. 276 (1657): 667–673. doi:10.1098/rspb.2008.1075. PMC 2660930. PMID 18957367.
  66. ^ Zelenitsky, Darla K.; Therrien, François; Ridgely, Ryan C.; McGee, Amanda R.; Witmer, Lawrence M. (13 April 2011). "Evolution of olfaction in non-avian theropod dinosaurs and birds". Proceedings of the Royal Society B: Biological Sciences. 278 (1725): 3625–3634. doi:10.1098/rspb.2011.0238. PMC 3203493. PMID 21490022.
  67. ^ Grellet-Tinner, Gerald; Makovicky, Peter (1 June 2006). "A possible egg of the dromaeosaur Deinonychus antirrhopus: phylogenetic and biological implications". Canadian Journal of Earth Sciences. 43 (6): 705–719. Bibcode:2006CaJES..43..705G. doi:10.1139/E06-033.
  68. ^ Wiemann, Jasmina; Yang, Tzu-Ruei; Norell, Mark A. (31 October 2018). "Dinosaur egg colour had a single evolutionary origin". Nature. 563 (7732): 555–558. Bibcode:2018Natur.563..555W. doi:10.1038/s41586-018-0646-5. PMID 30464264. S2CID 53188171.
  69. ^ Wu, Rui; Niu, Kecheng; Zhang, Shukang; Xue, Yu; Han, Fenglu (2024). "A new ootype of putative dromaeosaurid eggs from the Upper Cretaceous of southern China". Cretaceous Research. 161. Bibcode:2024CrRes.16105909W. doi:10.1016/j.cretres.2024.105909.
  70. ^ Parsons, William L.; Parsons, Kristen M. (2015). "Morphological Variations within the Ontogeny of Deinonychus antirrhopus (Theropoda, Dromaeosauridae)". PLOS ONE. 10 (4): e0121476. Bibcode:2015PLoSO..1021476P. doi:10.1371/journal.pone.0121476. PMC 4398413. PMID 25875499.
  71. ^ Chiarenza, Alfio Alessandro; Fiorillo, Anthony R.; Tykoski, Ronald S.; McCarthy, Paul J.; Flaig, Peter P.; Contreras, Dori L. (2020). "The first juvenile dromaeosaurid (Dinosauria: Theropoda) from Arctic Alaska". PLOS ONE. 15 (7): e0235078. Bibcode:2020PLoSO..1535078C. doi:10.1371/journal.pone.0235078. PMC 7343144. PMID 32639990.
  72. ^ Erickson, Gregory M.; Curry Rogers, Kristina; Varricchio, David J.; Norell, Mark A.; Xu, Xing (2007). "Growth patterns in brooding dinosaurs reveals the timing of sexual maturity in non-avian dinosaurs and genesis of the avian condition". Biology Letters. 3 (5): 558–561. doi:10.1098/rsbl.2007.0254. PMC 2396186. PMID 17638674.
  73. ^ Pittman, Michael; Xu, Xing (2020). "Pennaraptoran Theropod Dinosaurs Past Progress and New Frontiers". Bulletin of the American Museum of Natural History. 440: 1. doi:10.1206/0003-0090.440.1.1.
  74. ^ a b c d e Powers, Mark J.; Fabbri, Matteo; Doschak, Michael R.; Bhullar, Bhart-Anjan S.; Evans, David C.; Norell, Mark A.; Currie, Philip J. (2021). "A new hypothesis of eudromaeosaurian evolution: CT scans assist in testing and constructing morphological characters". Journal of Vertebrate Paleontology. 41 (5). Bibcode:2021JVPal..41E0087P. doi:10.1080/02724634.2021.2010087.
  75. ^ Brusatte, Stephen L.; Lloyd, Graeme T.; Wang, Steve C.; Norell, Mark A. (2014). "Gradual Assembly of Avian Body Plan Culminated in Rapid Rates of Evolution across the Dinosaur-Bird Transition" (PDF). Current Biology. 24 (20): 2386–2392. doi:10.1016/j.cub.2014.08.034. PMID 25264248. S2CID 8879023.
  76. ^ a b c d e f g h i j k l m n o Napoli, J. G.; Ruebenstahl, A. A.; Bhullar, B.-A. S.; Turner, A. H.; Norell, M. A. (2021). "A New Dromaeosaurid (Dinosauria: Coelurosauria) from Khulsan, Central Mongolia" (PDF). American Museum Novitates (3982): 1–47. doi:10.1206/3982.1. hdl:2246/7286. ISSN 0003-0082. S2CID 243849373.
  77. ^ a b c d Cau, Andrea; Beyrand, Vincent; Voeten, Dennis F. A. E.; Fernandez, Vincent; Tafforeau, Paul; Stein, Koen; Barsbold, Rinchen; Tsogtbaatar, Khishigjav; Currie, Philip J. (December 2017). "Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs". Nature. 552 (7685): 395–399. Bibcode:2017Natur.552..395C. doi:10.1038/nature24679. ISSN 1476-4687. PMID 29211712. S2CID 4471941.
  78. ^ a b c d e f g h i j k l m n Averianov, A. O.; Lopatin, A. V. (2021). "A New Theropod Dinosaur (Theropoda, Dromaeosauridae) from the Late Cretaceous of Tajikistan". Doklady Earth Sciences. 499 (1): 570–574. Bibcode:2021DokES.499..570A. doi:10.1134/S1028334X21070047. S2CID 239088573.
  79. ^ Turner, A.H.; Montanari, S.; Norell, M.A. (2021). "A new dromaeosaurid from the Late Cretaceous Khulsan locality of Mongolia". American Museum Novitates (3965): 1–46. doi:10.1206/3965.1.
  80. ^ a b c d e f g h i j k l m n Hartman, S.; Mortimer, M.; Wahl, W.R.; Lomax, D.R.; Lippincott, J.; Lovelace, D.M. (2019). "A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight". PeerJ. 7: e7247. doi:10.7717/peerj.7247. PMC 6626525. PMID 31333906.
  81. ^ Matías J. Motta; Federico L. Agnolín; Federico Brissón Egli; Fernando E. Novas (2020). "New theropod dinosaur from the Upper Cretaceous of Patagonia sheds light on the paravian radiation in Gondwana". The Science of Nature. 107 (3): Article number 24. Bibcode:2020SciNa.107...24M. doi:10.1007/s00114-020-01682-1. hdl:11336/135530. PMID 32468191. S2CID 218913199.
  82. ^ a b Barsbold, R. (1983). "Хищные динозавры мела Монголии" [Carnivorous dinosaurs from the Cretaceous of Mongolia] (PDF). Transactions of the Joint Soviet-Mongolian Paleontological Expedition (in Russian). 19: 89. Translated paper
  83. ^ Sereno, P. C. (1998). "A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 210 (1): 41–83. doi:10.1127/njgpa/210/1998/41.
  84. ^ a b Godefroit, Pascal; Cau, Andrea; Hu, Dong-Yu; Escuillié, François; Wu, Wenhao; Dyke, Gareth (2013). "A Jurassic avialan dinosaur from China resolves the early phylogenetic history of birds". Nature. 498 (7454): 359–362. Bibcode:2013Natur.498..359G. doi:10.1038/nature12168. PMID 23719374. S2CID 4364892. Cite error: The named reference "AurornisNature" was defined multiple times with different content (see the help page).
  85. ^ a b c d e f Evans, D. C.; Larson, D. W.; Currie, P. J. (2013). "A new dromaeosaurid (Dinosauria: Theropoda) with Asian affinities from the latest Cretaceous of North America". Naturwissenschaften. 100 (11): 1041–9. Bibcode:2013NW....100.1041E. doi:10.1007/s00114-013-1107-5. PMID 24248432. S2CID 14978813.
  86. ^ a b c d Cau A. (2024). A Unified Framework for Predatory Dinosaur Macroevolution. Bollettino della Società Paleontologica Italiana, 63(1): 1-19.
  87. ^ a b c d e f g h Czepiński, Łukasz (2023). "Skull of a dromaeosaurid Shri devi from the Upper Cretaceous of the Gobi Desert suggests convergence to the North American forms". Acta Palaeontologica Polonica. 68. doi:10.4202/app.01065.2023. S2CID 259441055.
  88. ^ a b c d e f g DePalma, R. A.; Burnham, D. A.; Martin, L. D.; Larson, P. L.; Bakker, R. T. (2015). "The First Giant Raptor (Theropoda: Dromaeosauridae) from the Hell Creek Formation". Paleontological Contributions (14). doi:10.17161/paleo.1808.18764.
  89. ^ a b Choiniere, Jonah N.; Clark, James M.; Norell, Mark A.; Xu, Xing (2014). "Cranial Osteology of Haplocheirus sollers Choiniere et al., 2010 (Theropoda: Alvarezsauroidea)". American Museum Novitates (3816): 1–44. doi:10.1206/3816.1. S2CID 4667472.
  90. ^ a b c Zanno, Lindsay E. (2010). "A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora)". Journal of Systematic Palaeontology. 8 (4): 503–543. Bibcode:2010JSPal...8..503Z. doi:10.1080/14772019.2010.488045.
  91. ^ a b c d e f Jasinski, Steven E.; Sullivan, Robert M.; Carter, Aja M.; Johnson, Erynn H.; Dalman, Sebastian G.; Zariwala, Juned; Currie, Philip J. (2022-11-07). "Osteology and reassessment of Dineobellator notohesperus, a southern eudromaeosaur (Theropoda: Dromaeosauridae: Eudromaeosauria) from the latest Cretaceous of New Mexico". The Anatomical Record: ar.25103. doi:10.1002/ar.25103. ISSN 1932-8486. PMID 36342817. S2CID 253382718.
  92. ^ Makovicky, P. J.; Apesteguía, S.; Agnolín, F. L. (2005). "The earliest dromaeosaurid theropod from South America". Nature. 437 (7061): 1007–1011. Bibcode:2005Natur.437.1007M. doi:10.1038/nature03996. PMID 16222297. S2CID 27078534.
  93. ^ a b c Agnolín, Federico L.; Motta, Matias J.; Brissón Egli, Federico; Lo Coco, Gastón; Novas, Fernando E. (2019-02-12). "Paravian Phylogeny and the Dinosaur-Bird Transition: An Overview". Frontiers in Earth Science. 6. doi:10.3389/feart.2018.00252. hdl:11336/130197. ISSN 2296-6463. Cite error: The named reference "tianyuraptor" was defined multiple times with different content (see the help page).
  94. ^ Currie, P. J. and D. J. Varricchio (2004). "A new dromaeosaurid from the Horseshoe Canyon Formation (Upper Cretaceous) of Alberta, Canada". Pp. 112–132 in P. J. Currie, E. B. Koppelhus, M. A. Shugar and J. L. Wright. (eds.), Feathered Dragons. Indianapolis: Indiana University Press. [1]
  95. ^ Pittman, M.; O'Connor, J.; Tse, E.; Makovicky, P.; Field, D.J.; Ma, W.; Turner, A.H.; Norell, M.A.; Pei, R.; Xu, X. (2020). "Chapter 2 – The Fossil Record of Mesozoic and Paleocene Pennaraptorans" (PDF). In Pittman, M.; Xing, X. (eds.). Pennaraptoran Theropod Dinosaurs: Past Progress and New Frontiers. Bulletin of the American Museum Of Natural History. pp. 37–95. doi:10.17863/CAM.59245. ISSN 0003-0090.
  96. ^ a b c d Currie, Philip J.; Evans, David C. (2020). "Cranial Anatomy of New Specimens of Saurornitholestes langstoni (Dinosauria, Theropoda, Dromaeosauridae) from the Dinosaur Park Formation (Campanian) of Alberta". The Anatomical Record. 303 (4): 691–715. doi:10.1002/ar.24241. PMID 31497925.
  97. ^ Bell, P. R.; Currie, P. J. (2015). "A high-latitude dromaeosaurid, Boreonykus certekorum, gen. et sp. nov. (Theropoda), from the upper Campanian Wapiti Formation, west-central Alberta". Journal of Vertebrate Paleontology. 36 (1). doi:10.1080/02724634.2015.1034359.
  98. ^ Kurzanov, S. M. (1976) Braincase structure in the carnosaur Itemirus n. gen. and some aspects of the cranial anatomy of dinosaurs. Paleontological Journal 10:361-369.
  99. ^ Sues, H.-D.; Averianov, A. (2014). "Dromaeosauridae (Dinosauria: Theropoda) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan and the phylogenetic position of Itemirus medullaris Kurzanov, 1976". Cretaceous Research. 51: 225–240. doi:10.1016/j.cretres.2014.06.007.
  100. ^ a b Averianov, Alexander O.; Lopatin, Alexey V. (2023-03-08). "New data on Kansaignathus sogdianus, a dromaeosaurid theropod from the Upper Cretaceous of Tajikistan". Cretaceous Research. 147: 105524. Bibcode:2023CrRes.14705524A. doi:10.1016/j.cretres.2023.105524. ISSN 0195-6671. S2CID 257453407.
  101. ^ a b Lü, J.-C.; Xu, L.; Zhang, X.-L.; Ji, Q.; Jia, S.-H.; Hu, W.-Y.; Zhang, J.-M.; Wu, Y.-H. (2007). "New dromaeosaurid dinosaur from the Late Cretaceous Qiupa Formation of Luanchuan area, western Henan, China". Geological Bulletin of China. 26 (7): 777–786.
  102. ^ a b Xu Xing; Choinere, J.N.; Pittman, M.; Tan, Q.W.; Xiao, D.; Li, Z.Q.; Tan, L.; Clark, J.M.; Norell, M.A.; Hone, D.W.E.; Sullivan, C. (2010). "A new dromaeosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Wulansuhai Formation of Inner Mongolia, China" (PDF). Zootaxa (2403): 1–9. Retrieved 2010-03-19.
  103. ^ Norell, M.A.; Clark, J.M.; Turner, A.H.; Makovicky, P.J.; Barsbold, R.; Rowe, T. (2006). "A new dromaeosaurid theropod from Ukhaa Tolgod (Ömnögov, Mongolia)". American Museum Novitates (3545): 1–51. doi:10.1206/0003-0082(2006)3545[1:ANDTFU]2.0.CO;2. hdl:2246/5823.
  104. ^ Arbour, V.M.; Zanno, L.E.; Larson, D.W.; Evans, D.C.; Sues, H. (2015). "The furculae of the dromaeosaurid dinosaur Dakotaraptor steini are trionychid turtle entoplastra". PeerJ. 3: e1957. doi:10.7717/peerj.1691. PMC 4756751. PMID 26893972.
  105. ^ Bonde, N.; Christiansen, P. (2003). "New dinosaurs from Denmark". Comptes Rendus Palevol. 2 (1): 13–26. Bibcode:2003CRPal...2...13B. doi:10.1016/S1631-0683(03)00009-5.
  106. ^ a b Lindgren, J.; Currie, P. J.; Rees, J.; Siverson, M.; Lindström, S.; Alwmark, C. (2008). "Theropod dinosaur teeth from the lowermost Cretaceous Rabekke Formation on Bornholm, Denmark". Geobios. 41 (2): 253–262. Bibcode:2008Geobi..41..253L. doi:10.1016/j.geobios.2007.05.001.
  107. ^ a b Rauhut, O. W. M.; Milner, A. C.; Moore-Fay, S. (2010). "Cranial osteology and phylogenetic position of the theropod dinosaur Proceratosaurus bradleyi (Woodward, 1910) from the Middle Jurassic of England". Zoological Journal of the Linnean Society. 158 (1): 155–195. doi:10.1111/j.1096-3642.2009.00591.x.
  108. ^ Milner, A. C. (2002). "Theropod dinosaurs of the Purbeck Limestone Group, southern England". Special Papers in Palaeontology. 68: 191–201.
  109. ^ Norell, M.A. and Makovicky, P. (1997). "Important features of the dromaeosaur skeleton: Information from a new specimen." American Museum Novitates, 3215: 1-28.
  110. ^ a b c Longrich, Nicholas R.; Martill, David M.; Jacobs, Megan L. (2022). "A new dromaeosaurid dinosaur from the Wessex Formation (Lower Cretaceous, Barremian) of the Isle of Wight, and implications for European palaeobiogeography". Cretaceous Research. 134. Bibcode:2022CrRes.13405123L. doi:10.1016/j.cretres.2021.105123.
  111. ^ Xu, X. and Wang, X. (2003). "A new maniraptoran dinosaur from the Early Cretaceous Yixian Formation of western Liaoning". Vertebrata PalAsiatica, 41(3): 195–202.
  112. ^ Lefèvre, Ulysse; Cau, Andrea; Cincotta, Aude; Hu, Dongyu; Chinsamy, Anusuya; Escuillié, François; Godefroit, Pascal (2017). "A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers". The Science of Nature. 104 (9–10): 74. Bibcode:2017SciNa.104...74L. doi:10.1007/s00114-017-1496-y. PMID 28831510. S2CID 253637872.
  113. ^ Xu Xing, Corwin Sullivan & Wang Shuo (2013) The systematic position of the enigmatic theropod dinosaur Yixianosaurus longimanus. Vertebrata PalAsiatica 51(3): 169-183
  114. ^ Hu, Dongyu; Hou, Lianhai; Zhang, Lijun; Xu, Xing (2009-09-24). "A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus". Nature. 461 (7264): 640–643. Bibcode:2009Natur.461..640H. doi:10.1038/nature08322. ISSN 0028-0836. PMID 19794491. S2CID 205218015.
  115. ^ a b Allison, Peter A.; Bottjer, David J. (2010), Taphonomy: Bias and Process Through Time, Topics in Geobiology, vol. 32, Springer Netherlands, pp. 1–17, doi:10.1007/978-90-481-8643-3_1, ISBN 9789048186426, S2CID 55502956
  116. ^ Upchurch, Paul; Hunn, Craig A; Norman, David B (2002-03-22). "An analysis of dinosaurian biogeography: evidence for the existence of vicariance and dispersal patterns caused by geological events". Proceedings of the Royal Society of London. Series B: Biological Sciences. 269 (1491): 613–621. doi:10.1098/rspb.2001.1921. ISSN 0962-8452. PMC 1690931. PMID 11916478.
  117. ^ Goodwin, M. B.; Clemens, W. A.; Hutchison, J. H.; Wood, C. B.; Zavada, M. S.; Kemp, A.; Duffin, C. J.; Schaff, C. R. (1999). "Mesozoic continental vertebrates with associated palynostratigraphic dates from the northwestern Ethiopian plateau". Journal of Vertebrate Paleontology. 19 (4): 728–741. doi:10.1080/02724634.1999.10011185.
  118. ^ Christiansen P. & Bonde N. (2003). "The first dinosaur from Denmark". Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 227 (2): 287–299. doi:10.1127/njgpa/227/2003/287.
  119. ^ Kirkland, J.I. (1998). "A new hadrosaurid from the upper Cedar Mountain Formation (Albian-Cenomanian: Cretaceous) of eastern Utah – the oldest known hadrosaurid (lambeosaurine?)". In Lucas, S.G.; Kirkland, J.I.; Estep, J.W. (eds.). Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin. Vol. 14. pp. 283–295.
  120. ^ Ding, Anyang; Pittman, Michael; Upchurch, Paul; O’Connor, Jingmai; Field, Daniel J.; Xu, Xing (2020). "The Biogeography of Coelurosaurian Theropods and its Impact on their Evolutionary History" (PDF). Bulletin of the American Museum of Natural History (440). doi:10.1101/634170.
  121. ^ "Deinonychus antirrhopus — Age range and collections". The Paleobiology Database. Retrieved 2024-07-11.
  122. ^ Buffetaut, Eric; Chanthasit, Phornphen (2009). "New data on the Dromaeosauridae (Dinosauria: Theropoda) from the Late Cretaceous of southern France". Bulletin de la Société Géologique de France. 180 (2): 145–154. doi:10.2113/gssgfbull.180.2.145.
  123. ^ Cau, Andrea; Brougham, Tom; Naish, Darren (2015). "The phylogenetic affinities of the bizarre Late Cretaceous Romanian theropod Balaur bondoc (Dinosauria, Maniraptora): Dromaeosaurid or flightless bird?". PeerJ. 3: e1032. doi:10.7717/peerj.1032. PMC 4476167. PMID 26157616.
  124. ^ Brownstein, Chase (2018). "The biogeography and ecology of the Cretaceous non-avian dinosaurs of Appalachia". Palaeontologia Electronica: 1–56. doi:10.26879/801.
  125. ^ a b le Loeuff, J. (2012). "Paleobiogeography and biodiversity of Late Maastrichtian dinosaurs: How many dinosaur species became extinct at the Cretaceous-Tertiary boundary?". Bulletin de la Société Géologique de France. 183 (6): 547–559. doi:10.2113/gssgfbull.183.6.547.
  126. ^ le Loeuff, J. (2012). "Paleobiogeography and biodiversity of Late Maastrichtian dinosaurs: How many dinosaur species became extinct at the Cretaceous-Tertiary boundary?". Bulletin de la Société Géologique de France. 183 (6): 547–559. doi:10.2113/gssgfbull.183.6.547.
  127. ^ Bonsor, Joseph A.; Barrett, Paul M.; Raven, Thomas J.; Cooper, Natalie (2020). "Dinosaur diversification rates were not in decline prior to the K-Pg boundary". Royal Society Open Science. 7 (11). doi:10.1098/rsos.201195. PMC 7735361. PMID 33391800.
  128. ^ Condamine, Fabien L.; Guinot, Guillaume; Benton, Michael J.; Currie, Philip J. (2021). "Dinosaur biodiversity declined well before the asteroid impact, influenced by ecological and environmental pressures". Nature Communications. 12. doi:10.1038/s41467-021-23754-0. PMID 34188028.
  129. ^ Robertson, D. S.; McKenna, M. C.; Toon, O. B.; et al. (2004). "Survival in the first hours of the Cenozoic" (PDF). Geological Society of America Bulletin. 116 (5–6): 760–768. Bibcode:2004GSAB..116..760R. doi:10.1130/B25402.1. S2CID 44010682. Archived from the original (PDF) on 2019-05-07.
  130. ^ King, J. Logan; Sipla, Justin S.; Georgi, Justin A.; Balanoff, Amy M.; Neenan, James M. (2020). "The endocranium and trophic ecology of Velociraptor mongoliensis". Journal of Anatomy. 237 (5): 861–869. doi:10.1111/joa.13253. PMC 7542195. PMID 32648601.
  131. ^ Wick, Steven L.; Lehman, Thomas M.; Brink, Alyson A. (2015). "A theropod tooth assemblage from the lower Aguja Formation (Early Campanian) of West Texas, and the roles of small theropod and varanoid lizard mesopredators in a tropical predator guild". Palaeogeography, Palaeoclimatology, Palaeoecology. 418: 229–244. Bibcode:2015PPP...418..229W. doi:10.1016/j.palaeo.2014.11.018.
  132. ^ Fiorillo, Anthony R.; Gangloff, Roland A. (2000). "Theropod teeth from the Prince Creek Formation (Cretaceous) of northern Alaska, with speculations on Arctic Dinosaur paleoecology". Journal of Vertebrate Paleontology. 20 (4): 675. doi:10.1671/0272-4634(2000)020[0675:TTFTPC]2.0.CO;2. ISSN 0272-4634.
Retrieved from "https://en.wikipedia.org/w/index.php?title=User:A_Cynical_Idealist/sandbox3&oldid=1234998057"