Halszkaraptor escuilliei is a Dromaeosaur (Theropods normally referred to as raptors) from the Halszkaraptorinae family. It is a small bipedal feathered dinosaur with a toothed beak, long flexible neck, short feathered arms, slender legs, and a long tail.
Halszkaraptor would have lived in the relatively dry area of what is now South-central Mongolia, near bodies of water; swimming in the water using its arms like flippers to hunt for fish, and laying eggs on land. Because of the completeness of the skeleton, it was able to be attributed to the new Halszkaraptorinae family, along with two other already-described Dromaeosaurs (Mahakala omnogovae, Hulsanpes perlei).
The holotype is an almost complete skeleton that wasn't flattened during the fossilization process. It is thought to have been poached from an unspecified area of Ukhaa Tolgod, a fossil-rich area of the Ömnögov province Mongolia. It was kept in private collections until 2015, when French fossil dealer François Escuillié transferred the specimen to the Royal Belgian Institute of Natural Sciences. It was then returned to the Institute of Paleontology and Geology, Mongolian Academy of Sciences and described in 2017.
Halszkaraptor is unique in the fact that it appears to have been at least partially aquatic, as evidenced by its arms being similar to modern swimming birds, serpentine neck, and and toothed beak similar to modern semi-aquatic birds. This was disputed in 2020, but that was heavily refuted by the original author, as the dispute contained many errors and innaccuracies.
Halszkaraptor means "Halszka's raptor". 'Halszka' to honour Halszka Osmólska, a Polish paleontologist who specialised in Mongolian dinosaurs, and who discovered the oldest-known member of the new Halszkaraptorinae family: Hulsanpes perlei. "Raptor" is because this is part of the group of dinosaurs known as raptors. Escuilliei is to honour François Escuillié, who helped return the holotype back to Mongolia after it was poached.