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 and formally described in 1982 by Halszka Osmólska, who noted that the genus is represented by an immature individual. Hulsanpes represents the first record of the basal dromaeosauridsubfamilyHalszkaraptorinae
.
History of discovery
Right partial wall of the braincase
The first
deinonychosaur taxon, but due to the lack of more material, she tentatively classified the genus as a dromaeosaurid taxon. In an etymological aspect, the generic name, Hulsanpes, can be translated as "Khulsan pes" and is derived from the Latinized name of the type locality Khulsan and the Latin pēs meaning "foot" (Hulsan + pēs). The specific name, perlei, is in honour to the veteran Mongolian paleontologist Altangerel Perle.[1]
Description
Artists reconstruction of Hulsanpes runningRight metatarsus and phalanx of metatarsal III in articulation
The holotype specimen is represented by a very small immature individual and therefore all the available data is somewhat limited. The roughly textured bones are indicators of an early stage of life, probably a post-hatchling chick. The genus itself can be distinguished in having the contact area of metatarsal III and IV straight in a frontal view and the lower end of metatarsal IV projected to the lower lateral side.[2]
Overall, the preserved right
phalanges preserved but only one being complete. The first phalanx of metatarsal III is very eroded missing most of its lower part but preserving the upper one; it remains articulated to the metatarsal. The first phalanx of metatarsal II is complete but the second one is severely damaged, lacking most of the lower region, however, it is articulated to the first phalanx.[1][2]
The partial
braincase is a small element, measuring just 1 cm (10 mm) in length, it is embedded in a small portion of the sandstone layer. In general, the morphology is very complex and has an irregular shape. Based on comparisons with other maniraptorans, the preserved portion can be identified as the right inner side of the prootic-opisthotic bones in the braincase.[2]
Classification
First and second phalanges of metatarsal II
When first described in 1982, Osmólska tentatively placed Hulsanpes within the
Averaptora incertae sedis based on the fact that the extremely gracile metatarsals are similar to Avialae and metatarsal III interpreted to be pinched at the upper region.[5] This latter statement has been proven to be incorrect though.[2]
After several inconsistencies surrounding the placement of the genus, in
sister species of Mahakala. The cladogram below is based on the results obtained in the phylogenetic analysis performed during the description using updated data from the Theropod Working Group:[6]
Hulsanpes has been re-classified as a halszkaraptorine taxon, updating various aspects about the life-style of these animals. Hulsanpes had a similar life-style to those of the modern-day
nests.[6][7] However, it appears to be that Hulsanpes may have been more terrestrial based on the holotype metatarsus, which features adaptations for a more subcursorial life-style, supporting the diversification within this subfamily.[2]
Paleoecology
The holotype specimen was recovered from the
source competition with other species in the formation.[2]
^Senter, P.; Barsbold, R.; Britt, B. B; Burnham, D. A. (2004). "Systematics and evolution of Dromaeosauridae (Dinosauria, Theropoda)". Bulletin of Gunma Natural History Museum. 8: 1–20.
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