Halszkaraptorinae is a basal ("primitive") subfamily of Dromaeosauridae (or possibly Unenlagiidae) that includes the enigmatic generaHalszkaraptor, Mahakala, and Hulsanpes. A comparison of the fossils of Halszkaraptor with the bones of extantcrocodilians and aquatic birds revealed evidence of a semiaquatic lifestyle.[1] The group is named after Polish paleontologist Halszka Osmólska.[2]
Description[]
Halszkaraptorinae is defined as the most inclusive clade that contains Halszkaraptor escuilliei but not Dromaeosaurus albertensis, Unenlagia comahuensis, Saurornithoides mongoliensis or Vultur gryphus. The subfamily is diagnosed by their long necks, proximalcaudal vertebrae with oriented articular processes (projections of the vertebra fits with an adjacent vertebra) and prominent zygapophyseallaminae (plates of bone that form the posterior walls of each vertebra), a flattened ulna with a sharp posterior margin, ilium with a shelf-like supratrochanteric (above the trochanter of the femur) process, metacarpal III shaft transversely as thick as that of metacarpal II, a posterodistal surface on the femoral shaft with an elongate fossa bound by a lateral crest and the proximal half of metatarsal III being unconstricted and markedly convex
anteriorly.[1]
Classification[]
The cladogram below is based on the phylogenetic analysis conducted in 2017 by Cau et al. using updated data from the Theropod Working Group in their description of Halszkaraptor.[1]
