Halszkaraptor

Halszkaraptor; Temporal range: Late Cretaceous PreЄ Є O S D C P T J K Pg N ↓
	Reconstruction of Halszkaraptor by Gabriel N. U.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Suborder:	Theropoda
Family:	†Dromaeosauridae
Subfamily:	†Halszkaraptorinae
Genus:	†Halszkaraptor; Cau et al., 2017
Type species
	†Halszkaraptor escuilliei; Cau et al., 2017

Halszkaraptor (meaning 'Halszka's seizer') is a genus of small dromaeosaurid theropod dinosaur. It lived in present-day Mongolia, likely in the Djadochta Formation, during the Late Cretaceous period around 75 million years ago. The genus contains one known species, Halszkaraptor escuilliei.

Description[]

220px-Halszkaraptor Size Comparison by PaleoGeek.svg — Size of *Halszkaraptor* compared to a human

The holotype specimen (MPC D-102/109) has been compared to the bones of extant crocodilians and aquatic birds, and found evidence of a semiaquatic lifestyle. A phylogenetic analysis revealed it was a member of the basal subfamily Halszkaraptorinae, along with Mahakala and Hulsanpes.

The type species 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, Khishigjav Tsogtbaatar, Philip John Currie, and Pascal Godefroit. The generic name combines a reference to the late Polish paleontologist Halszka Osmólska, who was involved in many expeditions to Mongolia and named the closely related Hulsanpes, with Latin raptor, "robber". The specific name honours Escuillié for having made the specimen available to science.

Scientists compared the type specimen fossil, to the bones of extant crocodilians and aquatic to semi-aquatic birds, and found possible evidence of a semiaquatic lifestyle. The Halszkaraptor was about the size of a duck. Halszkaraptor likely 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.

News reconstruction Halszkaraptor escuilliei Saint Thomas Production — A Speculative Illustration of *Halszkraptor* with a differently colored plumage and consuming fish; by Saint_Thomas_Production

However a latter publication by the Nature' documentary site has cast Doubt to this animal's degree of aquatic abilities, if it had any at all. The documentary concluded that this animal showed the basic patterns of the maniraptorans and had transationary features with no identifiable aquatic inclinations.

These studies are prone to change; and further evaluation continues. A more recent analysis performed by Cau specifically points out similarities to modern-day mergansers. 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 model including forelimb-propelled locomotion. This particular behaviour has also been inferred for Halszkaraptor, and seems to support a piscivorous and aquatic life-style similar to that of mergansers.

Classification[]

In 2017, Halszkaraptor was placed in the Dromaeosauridae family and a new clade, Halszkaraptorinae, was made, in which Hulsanpes and Mahakala were also placed. A phylogenetic analysis done by Cau et al. in 2017 recovered Halszkaraptorinae as the most basal dromaeosaurid clade known to date, and found that Halszkaraptor was located in a more basal sister group to a clade formed by Hulsanpes and Mahakala.

Dicovery and History[]

Halszkraptor fossil — Fossil of *Halskaraptor*

The holotype specimen of Halszkaraptor likely came from the Djadochta Formation 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 in Brussels, showing it to paleontologists Pascal Godefroit 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, Cau and other prominent paleontologists described the genus in a detailed study published in the journal Nature. The fossil was returned to the Mongolian authorities.

The holotype, MPC D-102/109, was found in a layer of orange sandstone of the Bayn Dzak Member of the Djadochta Formation, dating from the late Campanian, 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.

Paleobiology[]

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 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.

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 in its mouth, a long neck and sensory neurons 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 eggs on land.

A more recent analysis performed by Cau specifically points out similarities to modern-day mergansers. 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 model including forelimb-propelled locomotion. This particular behaviour has also been inferred for Halszkaraptor, and seems to support a piscivorous and aquatic life-style similar to that of mergansers.

Then, in 2019, Brownstein argued that some of Halszkaraptor's "sub-aquatic" features did not actually support the semi-aquatic lifestyle that had been proposed for it, and that Halszkaraptor was probably just a basal transitional dromaeosaur with weird features. This argument was rebutted by Cau a year later.

In 2021, Hone and Holt suggested that although Halszkaraptor had no flattened unguals, many modern aquatic birds shared this trait, and so having flattened unguals does not actually suggest Halszkaraptor's swimming ability.

in 2022, Fabbri and colleagues challenged Halszkaraptor's semi-aquatic ecology when their analysis of bone-density showed that Halszkaraptor had a low bone-density, unlike modern semi-aquatic animals whose high bone-density suggests subaqueous foraging.

Halszkaraptor

Contents

Description[]

Classification[]

Dicovery and History[]

Paleobiology[]

In popular culture[]

Other Wikis[]

Gallery[]

References[]

Halszkaraptor Temporal range: Late Cretaceous PreЄ Є O S D C P T J K Pg N ↓

Reconstruction of Halszkaraptor by Gabriel N. U.
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Suborder:	Theropoda
Family:	†Dromaeosauridae
Subfamily:	†Halszkaraptorinae
Genus:	†Halszkaraptor Cau et al., 2017
Type species
†Halszkaraptor escuilliei Cau et al., 2017