Halszkaraptor
   HOME

TheInfoList



OR:

''Halszkaraptor'' (; meaning " Halszka's seizer") is a
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of
waterfowl Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae (three species of screamers), Anseranatidae (the magpie goose), and Anatidae, the largest family, which i ...
-like
dromaeosaurid Dromaeosauridae () is a family of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...
dinosaurs from
Mongolia Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 million, ...
that lived during the Late
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
period. It contains only one known
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
, ''Halszkaraptor escuilliei''. The type specimen (
holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...
) has been compared to the
bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...
s of extant
crocodilia Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period ( Cenomanian stage) and are the closest livi ...
ns and
aquatic birds A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in freshwater ecosystems, although others make no distinction from seabi ...
, and found evidence of a
semiaquatic In biology, semiaquatic can refer to various types of animals that spend part of their time in water, or plants that naturally grow partially submerged in water. Examples are given below. Semiaquatic animals Semi aquatic animals include: * Ve ...
lifestyle, while some researchers question about semiaquatic ecology. A
phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
analysis revealed it was a member of the basal subfamily
Halszkaraptorinae Halszkaraptorinae is a basal ("primitive") subfamily of Dromaeosauridae (or possibly Unenlagiidae) that includes the enigmatic genera '' Halszkaraptor'', '' Natovenator'', ''Mahakala'', and ''Hulsanpes''. Halszkaraptorines are definitively known ...
, along with ''
Mahakala Mahākāla is a deity common to Hinduism and Tantric Buddhism. In Buddhism, Mahākāla is regarded as the sacred '' Dharmapāla'' ("Protector of the Dharma"), while in Hinduism, Mahākāla is a fierce manifestation of the Hindu god Shiva and th ...
'' and ''
Hulsanpes ''Hulsanpes'' ( meaning " Khulsan foot") is a genus of halszkaraptorine theropod dinosaurs that lived during the Late Cretaceous in what is now the Barun Goyot Formation of Mongolia, about 75-72 million years ago. The remains were found in 1970 a ...
''.


History of discovery

The
holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...
specimen of ''Halszkaraptor'' likely came from the
Djadochta Formation The Djadochta Formation (sometimes Transcription (linguistics), transcribed and also known as Djadokhta, Djadokata, or Dzhadokhtskaya) is a highly fossiliferous geological formation situated in Central Asia, Gobi Desert, dating from the Late Creta ...
at Ukhaa Tolgod in southern Mongolia, and was illegally removed by fossil poachers. The fossil found its way to Japan and Great Britain, being owned by several collectors for some years until the Eldonia company of fossil dealer François Escuillié obtained it. He identified it as a new species, and in 2015 took it to the
Royal Belgian Institute of Natural Sciences The Museum of Natural Sciences of Belgium (french: Muséum des sciences naturelles de Belgique, nl, Museum voor Natuurwetenschappen van België) is a museum dedicated to natural history, located in Brussels, Belgium. The museum is a part of t ...
in
Brussels Brussels (french: Bruxelles or ; nl, Brussel ), officially the Brussels-Capital Region (All text and all but one graphic show the English name as Brussels-Capital Region.) (french: link=no, Région de Bruxelles-Capitale; nl, link=no, Bruss ...
, showing it to
paleontologists Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...
Pascal Godefroit Pascal Godefroit is a Belgian paleontologist. He discovered dinosaurs like '' Olorotitan'' in 2003. Godefroit is the director of earth and life sciences This list of life sciences comprises the branches of science that involve the scientific st ...
and Andrea Cau for further verification. After verifying its authenticity, among other means by scanning it with synchrotron radiation, a beam of X-rays, at the
European Synchrotron Radiation Facility The European Synchrotron Radiation Facility (ESRF) is a joint research facility situated in Grenoble, France, supported by 22 countries (13 member countries: France, Germany, Italy, the UK, Spain, Switzerland, Belgium, the Netherlands, Denmark, ...
, Cau and other prominent paleontologists described the genus in a detailed study published in the journal ''
Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
''. The fossil was returned to the Mongolian authorities.Supplementary Information
/ref> The holotype, MPC D-102/109, was found in a layer of orange
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...
of the Bayn Dzak Member of the Djadochta Formation, dating from the late
Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...
, about seventy-five million years old. It consists of a relatively complete skeleton with skull. In 2017, the fossil was not further prepared. Work by the fossil dealers had at that point generally exposed the left side of the skeleton. The synchrotron revealed that the bones continued into the rock and that the piece was probably not a chimaera, an artificial assembly of bones of disparate species, though the top of the snout had been restored with plaster and some elements had been reattached to the rock by glue. The skeleton is largely articulated and not compressed. It represents a subadult individual, about one year old. The
type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...
''Halszkaraptor escuilliei'' was in 2017 named and described by Andrea Cau, Vincent Beyrand, Dennis F. A. E. Voeten, Vincent Fernandez, Paul Tafforeau, Koen Stein,
Rinchen Barsbold , Rinchyengiin Barsbold, born December 21, 1935 in Ulaanbaatar) is a Mongolian paleontologist and geologist. He works with the Institute of Geology, at Ulaanbaatar, Mongolia. He is an expert in vertebrate paleontology and Mesozoic stratigraphy. Bar ...
, Khishigjav Tsogtbaatar,
Philip John Currie Philip John Currie (born March 13, 1949) is a Canadian palaeontologist and museum curator who helped found the Royal Tyrrell Museum of Palaeontology in Drumheller, Alberta and is now a professor at the University of Alberta in Edmonton. In the ...
, and Pascal Godefroit. The generic name combines a reference to the late Polish paleontologist
Halszka Osmólska Halszka Osmólska (September 15, 1930 – March 31, 2008) was a Polish paleontologist who had specialized in Mongolian dinosaurs. Biography She was born in 1930 in Poznań. In 1949, she began to study biology at Faculty of Biology and Earth Scie ...
, who was involved in many expeditions to Mongolia and named the closely related ''
Hulsanpes ''Hulsanpes'' ( meaning " Khulsan foot") is a genus of halszkaraptorine theropod dinosaurs that lived during the Late Cretaceous in what is now the Barun Goyot Formation of Mongolia, about 75-72 million years ago. The remains were found in 1970 a ...
'', with
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
''raptor'', "robber". The specific name honours Escuillié for having made the specimen available to science.


Description

''Halszkaraptor'' was about the size of a
mallard duck The mallard () or wild duck (''Anas platyrhynchos'') is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurasia, and North Africa, and has been introduced species, introduced to New Zealand, Australia, Peru, Bra ...
. The head was about long, the neck , the back and the sacrum . The describing authors indicated some distinguishing traits. Some of these were
autapomorphies In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to t ...
, unique derived characters. The
premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...
, the front snout bone, forms a flattened snout, occupying 32% of the snout length. The premaxilla bears eleven teeth. The
jugal bone The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species. Anato ...
is rod-shaped and its ascending branch occupies only a tenth of the bar behind the eye socket, not reaching the orbit. The neck is extremely elongated, representing half of the snout-sacrum length. The
postzygapophyses The articular processes or zygapophyses ( Greek ζυγον = " yoke" (because it links two vertebrae) + απο = "away" + φυσις = " process") of a vertebra are projections of the vertebra that serve the purpose of fitting with an adjacent vert ...
, rear joint processes, of the neck vertebrae bear no epipophyses, additional processes on their upper rim. The neck vertebrae have extremely reduced
neural spine The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...
s: on the second to fifth vertebrae these are only low ridges and subsequent neck vertebrae lack them completely. In the second to fifth neck vertebrae the normally paired postzygapophyses have fused into a single lobe-shaped process. The neural spines of the tail vertebrae are extremely shortened: at the first three tail vertebrae they are formed like low bumps and subsequent tail vertebrae lack them completely. The chevrons of the tail base are large with a pentagonal profile. The first phalanx of the third finger has 47% of the length of the third
metacarpal In human anatomy, the metacarpal bones or metacarpus form the intermediate part of the skeletal hand located between the phalanges of the fingers and the carpal bones of the wrist, which forms the connection to the forearm. The metacarpal bones ar ...
. Furthermore, a unique combination is present of traits that in themselves are not unique. The external bony
nostril A nostril (or naris , plural ''nares'' ) is either of the two orifices of the nose. They enable the entry and exit of air and other gasses through the nasal cavities. In birds and mammals, they contain branched bones or cartilages called turbi ...
is situated behind the main body of the premaxilla, the point where it connects to the front branch of the
maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...
. The descending branch of the
postorbital bone The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some v ...
is rod-shaped. The number of vertebrae of the neck and back totals twenty-two. Only the seventh, eighth and ninth neck vertebrae have pleurocoels, pneumatic depressions on their sides. The transition between the tail base and the middle tail is situated at the seventh to eighth vertebra. The third finger is longer than the second finger.


Skull

The snout, though elongated, is transversely expanded in front, creating a spoon-shaped profile in top view. It is also flat, and its width is 180% of its height. The top profile in side view is hollow. The expanded area consists of a relatively long premaxilla. This bone is internally excavated by a system of air chambers. From a larger chamber in the rear, neurovascular channels permeate the entire bone, not just the sides as in ''
Neovenator ''Neovenator'' (nee-o-ven-a-tor meaning "new hunter") is a genus of carcharodontosaurian theropod dinosaur. It is known from several skeletons found in the Early Cretaceous (Barremian~130-125 million years ago) Wessex Formation on the south coa ...
'', but the top also. These channels probably housed electro-sensory organs. Each premaxilla bears eleven teeth, a record among the entire Dinosauria. Theropods normally have four premaxillary teeth and the previous record for this group was seven, as found in
spinosaurids The Spinosauridae (or spinosaurids) are a clade or family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. They came into prominence during the Cretaceous period. Spinosaurid fossils have been recovered worldwide, includi ...
. In ''Halskaraptor'', the premaxillary teeth are very closely packed, touching each other, and are very elongated, gradually recurving. The teeth in the maxilla, estimated in number at twenty to twenty-five, are more robust, curve only at their tips, and are spaced at a larger distance. They are more transversely flattened, with an oval cross-section. The
dentary In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
of the lower jaw likewise bears an estimated twenty to twenty-five teeth. The nostrils are relatively retracted. They are also unique for a theropod in being obliquely oriented to the top in front view. Despite the length of the snout, the main opening in the side of the front skull, the
antorbital fenestra An antorbital fenestra (plural: fenestrae) is an opening in the skull that is in front of the eye sockets. This skull character is largely associated with archosauriforms, first appearing during the Triassic Period. Among extant archosaurs, bird ...
, is short; shorter than high. The rear skull roof is vaulted.


Postcranial skeleton

The
vertebral column The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordate ...
of ''Halszkaraptor'' contains ten neck vertebrae, twelve back vertebrae and six sacral vertebrae. The preserved tail vertebrae include the first twenty caudals and a series of six from the middle tail. The neck is very elongated. It equals 290% of the skull length and 150% of the back length. This implies that it represents half of the snout-sacrum length, a value that is the highest for all known Mesozoic paravians. Within the Paraves, only some more recent birds have a proportionally longer neck. Among more basal theropods only some
oviraptorosaurs Oviraptorosaurs ("egg thief lizards") are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, with or ...
approach this value; even ornithomimosaurs never surpass 40%. The length is not caused by a greater number of vertebrae, as in the Oviraptorosauria, but by an elongation of the individual vertebrae. The sixth cervical vertebra is the longest, being four times longer than tall. The neck vertebrae generally have a simplified structure, as exemplified by the lack of rear epipophyses. Most are not pneumatised by pleurocoels, depressions in which diverticula of
air sac Air sacs are spaces within an organism where there is the constant presence of air. Among modern animals, birds possess the most air sacs (9–11), with their extinct dinosaurian relatives showing a great increase in the pneumatization (presence ...
s penetrate the bone walls. On the front neck, the neural spines, normally rectangular plates, have been reduced to a low ridge; more to behind they have disappeared. At the first five neck vertebrae, the postzygapophyses have no separating space in between them but are fused into a single lobe. With other basal maniraptoriforms these rear joint processes are sometimes connected by a plate, but in that case the bony shelf is notched by a postspinal fossa causing a concave profile in top view; in ''Halszkaraptor'' this groove is absent and the profile is convex. The neck ribs are short, no longer than the vertebral bodies. The back vertebrae are not pneumatised. The tail is not stiffened by long zygapophyses or chevrons as in derived eudromaeosaurs. The tail base is rather short in that the transition point to the middle tail, where the transverse processes cease to exist, is at the eighth vertebra. The transition is also very gradual in morphology. The neural spines of the front tail are already strongly reduced: only the first three vertebrae possess them and they are formed like low bumps.


Classification

''Halszkaraptor'' was placed in the
Dromaeosauridae Dromaeosauridae () is a family of feathered theropod dinosaurs. They were generally small to medium-sized feathered carnivores that flourished in the Cretaceous Period. The name Dromaeosauridae means 'running lizards', from Greek ('), meaning ...
in 2017. A new clade
Halszkaraptorinae Halszkaraptorinae is a basal ("primitive") subfamily of Dromaeosauridae (or possibly Unenlagiidae) that includes the enigmatic genera '' Halszkaraptor'', '' Natovenator'', ''Mahakala'', and ''Hulsanpes''. Halszkaraptorines are definitively known ...
was coined, containing ''Halszkaraptor'' and its close relatives ''Hulsanpes'' and ''Mahakala''. The
cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...
below is based on the phylogenetic analysis conducted in 2017 by Cau ''etal.'' using updated data from the Theropod Working Group. The analysis showed that Halszkaraptorinae was the basalmost known dromaeosaurid group. ''Halszkaraptor'' occupied a basal position within Halszkaraptorinae, as the sister group of a clade formed by ''Hulsanpes'' and ''Mahakala''.


Paleobiology

Andrea Cau argues that ''Halszkaraptor'' had characteristics that allowed it to spend time both in water and on land, including strong hindlimbs for running and smaller flipper-like forelimbs for swimming. The short tail would have brought the
centre of gravity In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force ma ...
more to the front, which is more useful for swimming than walking. The torso would have been held more vertical than is normal with theropods. To this end, there are adaptations for an improved extension of the hindlimb, in the hip joint and the thighbone. It had many sharp, backward-curving
teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, t ...
in its mouth, a long neck and
sensory neuron Sensory neurons, also known as afferent neurons, are neurons in the nervous system, that convert a specific type of stimulus, via their receptors, into action potentials or graded potentials. This process is called sensory transduction. The cel ...
s in its snout that may have allowed it to detect vibrations in water, leading scientists to believe that it hunted aquatic prey. It had to come up onto land to reproduce, because, like all dinosaurs, it needed to lay its
egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...
s on land. A more recent analysis performed by Cau specifically points out similarities to modern-day
merganser ''Mergus'' is the genus of the typical mergansers , fish-eating ducks in the subfamily Anatinae. The genus name is a Latin word used by Pliny the Elder and other Roman authors to refer to an unspecified waterbird. The common merganser (''Mer ...
s. He stated that these birds are probably the closest ecological analogs to ''Halszkaraptor'' as they share similar traits with this dromaeosaurid taxon, such as the long neck and a serrated snout edge used to catch small prey. While they are less active moving on land, assuming a hip-extended body posture, on water, they use a distinct
swimming Swimming is the self-propulsion of a person through water, or other liquid, usually for recreation, sport, exercise, or survival. Locomotion is achieved through coordinated movement of the limbs and the body to achieve hydrodynamic thrust that r ...
model including forelimb-propelled locomotion. This particular behaviour has also been inferred for ''Halszkaraptor'', and seems to support a
piscivorous A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evoluti ...
and aquatic life-style similar to that of mergansers. Other researchers have either disagreed with or merely followed Cau's interpretation. In 2019, Brownstein argued that the features noted for ''Halszkaraptor'' do not directly support its ability to swim. He also suggested that this dinosaur may be a basal dromaeosaur with transitional features, although Cau rebutted his claims a year later. In 2021, Hone and Holtz noted that since ''Halszkaraptor'' and many modern aquatic birds with no flattened
ungual An ungual (from Latin ''unguis'', i.e. ''nail'') is a highly modified distal toe bone which ends in a hoof, claw, or nail. Elephants and ungulates have ungual phalanges, as did the sauropod Sauropoda (), whose members are known as sauropods (; ...
s is said to be semi-aquatic, having flattened unguals like ''Spinosaurus'' do not necessarily suggest that the animal can swim; they didn't propose their own view on this dinosaur's potential ability to swim. In 2022, Fabbri and his colleagues doubted Cau's interpretation based on their analysis on bone density on many theropods which showed that ''Halszkaratpor'' had low bone density, a trait not observed in semi-aquatic animals.


See also

*
Timeline of dromaeosaurid research This timeline of dromaeosaurid research is a chronological listing of events in the history of paleontology focused on the dromaeosaurids, a group of sickle-clawed, bird-like theropod dinosaurs including animals like ''Velociraptor''. Since the ...


References


External links

* *
3D skeletal model of ''Halszkaraptor escuilliei''
at
Sketchfab Sketchfab is a 3D modeling platform website to publish, share, discover, buy and sell 3D, VR and AR content. It provides a viewer based on the WebGL and WebXR technologies that allows users to display 3D models on the web, to be viewed on ...
{{Taxonbar, from=Q44884994 Djadochta fauna Dromaeosaurs Fossil taxa described in 2017