Halszkaraptorinae

{{Short description|Extinct subfamily of dinosaurs}} {{Automatic taxobox | name = Halszkaraptorines | fossil_range = [[Late Cretaceous]],<br />{{fossilrange|75|71|earliest=Early Cretaceous}}<small>Possible [[Early Cretaceous]] record<ref>{{Cite journal|last1=Kubota |first1=K. |last2=Kobayashi |first2=Y. |last3=Ikeda |first3=T. |title=Early Cretaceous troodontine troodontid (Dinosauria: Theropoda) from the Ohyamashimo Formation of Japan reveals the early evolution of Troodontinae |year=2024 |journal=Scientific Reports |volume=14 |issue=1 |at=16392 |doi=10.1038/s41598-024-66815-2 |doi-access=free |pmid=39054320 |pmc=11272788 |bibcode=2024NatSR..1416392K }}</ref></small> | image = Halszkaraptor escuilliei holotype.png | image_upright = 1.15 | image_caption = Holotype specimen of ''[[Halszkaraptor|Halszkaraptor escuilliei]]'' | taxon = Halszkaraptorinae | authority = Cau ''et al.'', 2017 | type_genus = †''[[Halszkaraptor escuilliei]]'' | type_genus_authority = Cau ''et al.'', 2017 | subdivision_ranks = Genera | subdivision = *†''[[Halszkaraptor]]'' *†''[[Hulsanpes]]'' *†''[[Mahakala omnogovae|Mahakala]]'' *†''[[Natovenator]]'' *†''[[Ningyuansaurus]]''? | synonyms = * '''Halszkaraptoridae'''? <small>Motta ''et al''., 2025</small> }}

'''Halszkaraptorinae''' is an extinct [[Basal (phylogenetics)|basal]] ("primitive") [[subfamily]] of [[Dromaeosauridae]] (or possibly [[Unenlagiidae]]) that includes the enigmatic [[Genus|genera]] ''[[Halszkaraptor]]'', ''[[Natovenator]]'', ''[[Mahakala (dinosaur)|Mahakala]]'', and ''[[Hulsanpes]]''. Halszkaraptorines are definitively known only from [[Late Cretaceous]] strata in [[Asia]], specifically in [[Mongolia]]. It is debated among researchers whether the group had a [[semiaquatic]] lifestyle.

==History of discovery== [[File:Cretaceous-aged dinosaur fossil localities of Mongolia.PNG|thumb|left|300px|[[Cretaceous]]-aged fossil localities of Mongolia; Halszkaraptorine fossils have been collected at the Khulsan (area A), Tugrik Shireh, and Ukhaa Tolgod localities (area B)]] The first known remains of halszkaraptorines were found in sandstone sediments in 1970 during a Polish-Mongolian expedition at the [[Barun Goyot Formation]], [[Gobi Desert]]. Later in 1982, they were described by [[Polish people|Polish]] [[paleontologist|palaeontologist]] [[Halszka Osmólska]] and used as the holotype for the new genus and species ''[[Hulsanpes perlei]]'', honoring the [[Mongolia]]n paleontologist [[Altangerel Perle]]. Although the affinities of these [[fossil]]s were not fully understood, they were tentatively interpreted as belonging to [[Deinonychosauria]].<ref>{{cite journal|last1=Osmólska|first1=H.|date=1982|title=Hulsanpes perlei n.g. n.sp. (Deinonychosauria, Saurischia, Dinosauria) from the Upper Cretaceous Barun Goyot Formation of Mongolia|journal=Neues Jahrbuch für Geologie und Paläontologie, Monatshefte|volume=1982|issue=7|pages=440–448|doi=10.1127/njgpm/1982/1982/440 }}</ref> In 1992 dromaeosaurid-like fossils were recovered from the Tugriken Shire locality of the [[Djadokhta Formation]] and described as a new species in 2007 by Alan H Turner and team. This new taxon, ''[[Mahakala omnogovae]]'', was regarded as a primitive dromaeosaurid mainly based on its body proportions.<ref name=Turner2007>{{cite journal|last1=Turner|first1=A.H.|last2=Pol|first2=D.|last3=Clarke|first3=J.A.|last4=Erickson|first4=G.M.|last5=Norell|first5=M.A.|date=2007|title=A Basal Dromaeosaurid and Size Evolution Preceding Avian Flight|journal=Science|volume=317|issue=5843|pages=1378–1381|bibcode=2007Sci...317.1378T|doi=10.1126/science.1144066|pmid=17823350|url=https://www.researchgate.net/publication/6017738}}</ref> In 2015 the [[Royal Belgian Institute of Natural Sciences]] received a small theropod fossil specimen, hailing from England and Japanese private collections. The specimen, through negotiations between the former institute, [[Eldonia (company)|Eldonia]] and Mongolian authorities, was lastly returned to the Institute of Paleontology and Geology, [[Mongolian Academy of Sciences]]. According to associated documents of the specimen, it was illegally poached from the Djadokhta Formation (Ukhaa Tolgod locality; however, sediments may suggest that, alternatively, it was recovered from nearby Bayn Dzak locality) during an unknown year, eventually falling into private collections. The specimen was formally described in 2017 by Andrea Cau with colleagues, naming the genus and species ''[[Halszkaraptor escuilliei]]'', in honor of Halszka Osmólska and [[François Escuillié]], paleontologists who made negotiations for returning the poached specimen to Mongolia possible. With the naming of ''Halszkaraptor'', the subfamily Halszkaraptorinae was also coined to contain this taxon and relatives, namely ''Hulsanpes'' and ''Mahakala''.<ref name=Cau2017>{{cite journal|last1=Cau|first1=A.|last2=Beyrand|first2=V.|last3=Voeten|first3=D. F. A. E.|last4=Fernandez|first4=V.|last5=Tafforeau|first5=P.|last6=Stein|first6=K.|last7=Barsbold|first7=R.|last8=Tsogtbaatar|first8=K.|last9=Currie|first9=P. J.|last10=Godefroit|first10=P.|date=2017|title=Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs|journal=Nature|volume=552|issue=7685|pages=395–399|bibcode=2017Natur.552..395C|doi=10.1038/nature24679|pmid=29211712|url=https://drive.google.com/file/d/1guyle258BS4kwD7Xwoh6ymDTPJOeqrdl/view|url-access=subscription}} [https://static-content.springer.com/esm/art%3A10.1038%2Fnature24679/MediaObjects/41586_2017_BFnature24679_MOESM1_ESM.pdf Supplementary Information]</ref>

==Description== [[File:Halszkaraptorinae size comparison.png|thumb|Size of known halszkaraptorines compared to a human]] Halszkaraptorines were relatively small theropods, reaching lengths similar to those of modern-day [[duck]]s.<ref name=Turner2007/><ref name=Cau2017/> They are diagnosed by their long necks, [[proximal]] [[caudal vertebrae]] with oriented [[articular processes]] (projections of the vertebra fits with an adjacent vertebra) and prominent [[Facet joint|zygapophyseal]] [[Lamina of the vertebral arch|laminae]] (plates of bone that form the posterior walls of each vertebra), a flattened [[ulna]] with a sharp [[Anatomical terms of location#Anterior and posterior|posterior]] margin, [[Ilium (bone)|ilium]] with a shelf-like supratrochanteric (above the [[trochanter]] of the femur) process, [[metacarpal]] III shaft [[Transverse plane|transversely]] as thick as that of metacarpal II, a posterodistal surface on the [[Femur#Other animals|femoral]] shaft with an elongate fossa bound by a [[Anatomical terms of location#Medial and lateral|lateral]] crest and the proximal half of [[metatarsal]] III being unconstricted and markedly convex [[anterior]]ly.<ref name=Cau2017/>

==Classification== Halszkaraptorinae is defined as the most inclusive clade that contains ''[[Halszkaraptor]] escuilliei'' but not ''[[Dromaeosaurus]] albertensis'', ''[[Unenlagia]] comahuensis'', ''[[Saurornithoides]] mongoliensis'' or ''[[Andean condor|Vultur gryphus]]''.<ref name=Cau2017/> The [[cladogram]] below is based on the phylogenetic analysis conducted in 2022 by Lee ''et al''. in their description of ''[[Natovenator]]''.<ref name="Natovenator">{{cite journal|last1=Lee|first1=S.|last2=Lee|first2=Y.-N.|last3=Currie|first3=P. J.|last4=Sissons|first4=R.|last5=Park|first5=J.-Y.|last6=Kim|first6=S.-H.|last7=Barsbold|first7=R.|last8=Tsogtbaatar|first8=K.|date=2022|title=A non-avian dinosaur with a streamlined body exhibits potential adaptations for swimming|journal=Communications Biology|volume=5|number=1185|page=1185 |doi=10.1038/s42003-022-04119-9|doi-access=free|pmid=36456823 |issn=2399-3642|pmc=9715538}}</ref>

{{clade| style=font-size:90%; line-height:90%; |label1=[[Dromaeosauridae]] |1={{clade |label1='''Halszkaraptorinae''' |1={{clade |1=''[[Halszkaraptor]]'' <div style="{{MirrorH}}">[[File:Halszkaraptor reconstruction by Tom Parker.png|80px]]</div> |2={{clade |1=''[[Natovenator]]'' |2=''[[Hulsanpes]]''<div style="{{MirrorH}}">[[File:Hulsanpes no background.png|60px]]</div> |3=''[[Mahakala omnogovae|Mahakala]]'' <div style="{{MirrorH}}">[[File:Mahakala omnogovae no background.png|60px]]</div>}} }} |2={{clade |1=[[Unenlagiinae]] <div style="{{MirrorH}}">[[File:Austroraptor Restoration.png|80px]]</div> |2={{clade |1=''[[Pyroraptor]]'' <div style="{{MirrorH}}">[[File:Pyroraptor olympius reconstruction.png|80px]]</div> |2={{clade |1=''[[Zhenyuanlong]]'' [[File:Zhenyuanlong life restoration (white background).jpg|60px]] |2=[[Microraptoria]] <div style="{{MirrorH}}">[[File:Changyuraptor.jpg|80px]]</div> |3={{clade |1=''[[Bambiraptor]]'' [[File:Bambiraptor reconstruction.jpg|80px]] |2=[[Eudromaeosauria]] <div style="{{MirrorH}}">[[File:Deinonychus ewilloughby.png|80px]]</div> }} }} }} }} }} }}

In 2025, Motta ''et al''., (2025) recovered Halszkaraptorinae (which they elevate to [[family (taxonomy)|family]] level) (along with [[Unenlagiidae]], [[Anchiornithidae]], and ''[[Archaeopteryx]]'') as within [[Avialae]].<ref name="Motta2025">{{cite journal |last1=Motta |first1=Matías J. |last2=Agnolína |first2=Federico L. |last3=Eglia |first3=Federico Brissón |last4=Rozadillaa |first4=Sebastián |last5=Novas |first5=Fernando E. |title=Phylogenetic relationships of Unenlagiidae among Paraves (Dinosauria) |journal=Journal of Systematic Palaeontology |date=22 Aug 2025 |volume=23 |issue=1 |doi=10.1080/14772019.2025.2529608 |url=https://www.tandfonline.com/doi/full/10.1080/14772019.2025.2529608 |access-date=22 August 2025|url-access=subscription }}</ref> The two trees recovered are reproduced below:

{{columns-start|num=2}} ;Consensus Improved (equal weighting) {{clade| style=font-size: 80%; line-height:75% |label1='''[[Pennaraptora]]''' |1={{clade |1={{clade |1=[[Scansoriopterygidae]] |2=[[Oviraptorosauria]] }} |label2=[[Paraves]] |2={{clade |1=[[Troodontidae]] |label2=[[Eumaniraptora]] |2={{clade |label1=[[Dromaeosauridae]] |1={{clade |1=[[Microraptoria]] |2=[[Eudromaeosauria|Eudromaeosauridae]] }} |label2=[[Avialae]] |2={{clade |label1=[[Unenlagiinia]] |1={{clade |1=[[Halszkaraptorinae|Halszkaraptoridae]] |2=[[Unenlagiidae]] }} |2={{clade |1={{clade |1=[[Anchiornithidae]] |2=''[[Archaeopteryx]]'' }} |2={{clade |1=''[[Jeholornis]]'' |2=[[Pygostylia]] }} }} }} }} }} }} }} {{column}} ;Consensus Improved (implied weighting) {{clade| style=font-size: 80%; line-height:75% |label1='''[[Pennaraptora]]''' |1={{clade |1={{clade |1=[[Scansoriopterygidae]] |2=[[Oviraptorosauria]] }} |label2=[[Paraves]] |2={{clade |1=[[Troodontidae]] |label2=[[Eumaniraptora]] |2={{clade |label1=[[Dromaeosauridae]] |1={{clade |1=[[Microraptoria]] |2=[[Eudromaeosauria|Eudromaeosauridae]] }} |label2=[[Avialae]] |2={{clade |label1=[[Unenlagiinia]] |1={{clade |1=[[Halszkaraptorinae|Halszkaraptoridae]] |2=[[Unenlagiidae]] }} |2={{clade |1=[[Anchiornithidae]] |2={{clade |1={{clade |1=''[[Fujianvenator]]'' |2=''[[Archaeopteryx]]'' }} |2={{clade |1=''[[Jeholornis]]'' |2=[[Pygostylia]] }} }} }} }} }} }} }} }} {{columns-end}}

==Paleobiology== [[File:Natovenator_hunting_fish.png|thumb|[[Paleoart|Life restoration]] of ''Natovenator'']] In 2017 a comparison of the fossils of ''Halszkaraptor'' with the [[bone]]s of [[Neontology|extant]] [[crocodilia]]ns and aquatic [[bird]]s revealed evidence of a [[semiaquatic]] lifestyle. Cau and colleagues suggested that halszkaraptorines were obligate [[biped]]s on land, but also [[Aquatic locomotion|swimmers]] that used its forelimbs to push through [[water]] and used their long necks for [[foraging]]. Such traits allowed them to exploit both terrestrial and aquatic paleoecosystems.<ref name="Cau2017" /> A 2024 study by Tse, Miller, and Pittman, focusing on the skull morphology and bite forces of various dromaeosaurids discovered that ''Halszkaraptor'' had a rapid bite unsuited to piscivorous feeding as previously hypothesized based on its skull morphology, and instead suggest it was an insectivore that hunted small invertebrates possibly in low-light conditions (at night or in murky water), since it likely had exceptional low-light vision among dromaeosaurids based on its relatively large orbit size.<ref>{{Cite journal|last1=Tse |first1=Y. T. |last2=Miller |first2=C. V. |last3=Pittman |first3=M. |year=2024 |title=Morphological disparity and structural performance of the dromaeosaurid skull informs ecology and evolutionary history |journal=BMC Ecology and Evolution |volume=24 |issue=1 |at=39 |doi=10.1186/s12862-024-02222-5 |pmid=38622512 |pmc=11020771 |doi-access=free |bibcode=2024BMCEE..24...39T }}</ref>

Other researchers have either disagreed with or merely followed Cau's interpretation as a semiaquatic dinosaur. 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,<ref name=":0">{{cite journal|last1=Brownstein|first1=C.D.|year=2019|title=''Halszkaraptor escuilliei'' and the evolution of the paravian bauplan|journal=Nature|volume=9|issue=1 |page=16455|doi=10.1038/s41598-019-52867-2|pmid=31712644 |pmc=6848195 |bibcode=2019NatSR...916455B |doi-access=free}}</ref> although Cau rebutted his claims a year later.<ref>{{cite journal|last1=Cau|first1=A.|date=2020|title=The body plan of Halszkaraptor escuilliei (Dinosauria, Theropoda) is not a transitional form along the evolution of dromaeosaurid hypercarnivory|journal=PeerJ|volume=8|article-number=e8672|doi=10.7717/peerj.8672|doi-access=free|pmc=7047864|pmid=32140312}}</ref> In 2021, Hone and Holtz noted that since ''Halszkaraptor'' and many modern aquatic birds with no flattened [[ungual]]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.<ref>{{cite journal |last1=Hone|first11=D.W.E.|last2=Holtz|first2=Thomas R. Jr.|title=Evaluating the ecology of Spinosaurus: Shoreline generalist or aquatic pursuit specialist? |journal=Palaeontologia Electronica |date=2021 |volume=24 |issue=1 |pages=a03|url=https://palaeo-electronica.org/content/2021/3219-the-ecology-of-spinosaurus|doi=10.26879/1110|doi-access=free|hdl=1903/28570|hdl-access=free}}</ref> In 2022, Fabbri and his colleagues argued against a semi-aquatic ecology for ''Halszkaraptor'', noting that it had low bone density, a trait not observed in semi-aquatic animals.<ref name=":1">{{cite journal |last1=Fabbri |first1=Matteo |last2=Navalón |first2=Guillermo |last3=Benson |first3=Roger B. J. |last4=Pol |first4=Diego |last5=O'Connor |first5=Jingmai |last6=Bhullar |first6=Bhart-Anjan S. |last7=Erickson |first7=Gregory M. |last8=Norell |first8=Mark A. |last9=Orkney |first9=Andrew |last10=Lamanna |first10=Matthew C. |last11=Zouhri |first11=Samir |last12=Becker |first12=Justine |last13=Emke |first13=Amanda |last14=Dal Sasso |first14=Cristiano |last15=Bindellini |first15=Gabriele |last16=Maganuco |first16=Simone |last17=Auditore |first17=Marco |last18=Ibrahim |first18=Nizar |title=Subaqueous foraging among carnivorous dinosaurs |journal=Nature |date=March 23, 2022 |volume=603 |issue=7903 |pages=852–857 |doi=10.1038/s41586-022-04528-0 |pmid=35322229 |bibcode=2022Natur.603..852F |s2cid=247630374 |url=https://ora.ox.ac.uk/objects/uuid:264b7ca2-1190-4b76-ab93-074cedf897e1 }}</ref> In response, Cau has pointed out on his blog that swans similarly have low bone density yet have adaptations for semi-aquatic feeding.<ref>{{Cite web|url=https://theropoda.blogspot.com/2022/03/limpatto-della-densita-ossea-di.html|title=Theropoda: L'impatto della densità ossea di Halszkaraptor sulla sua ecologia|first=Andrea|last=Cau|date=26 March 2022|access-date=28 March 2023}}</ref>

==References== {{Reflist}}

{{Dromaeosauridae}} {{Taxonbar|from=Q44884133}}

[[Category:Halszkaraptorinae| ]] [[Category:Dinosaur subfamilies]] [[Category:Campanian dinosaurs]] [[Category:Dinosaurs of Mongolia]]