[D] Hulsanpes perlei [sG] [T]
Describer
Osmolska, 1982
Time
Cretaceous Late Campanian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Dromaeosauridae
Diet
Carnivore
Fossilsite
Barun Goyot Formation, Khulsan, Mongolia
Info
Genus - Typespecies
Comments by Mickey Mortimer
Etymology
\\\"Perle\\\'s Khulsan foot\\\", Altangerel Perle being a paleontologist and Khulsan being the Mongolian locality where it was discovered. mid Campanian, Late Cretaceous Barun Goyot Formation, Mongolia
Holotype
(ZPAL MgD-I/173) (juvenile) (30-40 cm) otico-occipital fragment, metatarsal II (~34 mm), phalanx II-1 (~6.5 mm), proximal phalanx II-2, metatarsal III (~39 mm), proximal phalanx III-1, metatarsal IV (~36 mm) Diagnosis- metatarsal III flattens and widens to overlap metatarsal II in anterior view.
Description
This specimen was discovered in 1970 and described twelve years later. Using Confuciusornis and Yandangornis as guides, we can estimate Hulsanpes was about 30-40 cm long, but it was juvenile based on the rough bone texture and the badly abraded articular joints. The metatarsus \\\"lacks even incipient fusion\\\" (contra Holtz), and is non-arctometatarsalian to the point that metatarsal III expands proximally. It is fairly slender and metatarsal III is slightly more robust than the others. Distally, metatarsal III flattens and widens to partially overlap metatarsal II.
The metatarsus is concave posteriorly, with metatarsal III inset compared to the others. The distal end of metatarsal III is shallowly grooved with a symmetrical ginglymus. The distal end of metatarsal IV is transversely flattened and diverges from metatarsal III. The articular surface is narrow and undivided, with a groove posterior to it. Pedal phalanx I-1 is rather similar to Deinonychus. The proximal end has an elongate articular surface divided asymmetrically by a ridge, showing that the articulation of metatarsal II was ginglymoid.
The distal end is divided asymmetrically by a long groove that extends more dorsally than ventrally. The medial condyle is a bit wider and lower. The ligamental fossae are deep and the lateral one is more centrally placed. Although the second digit could apparently hyperextend, the proximoventral heel of phalanx II-2 was not well-developed.
Relationships
First of all, let\\\'s try to figure out why Hulsanpes has been connected to birds lately. Tom Holtz wrote in September of 1995 that the metatarsals and distal tarsals are fused at least distally in this species, like birds. He also cryptically said \\\"future work may show why this is no surprise....\\\".
Then in May of 1997, Tom said that Hulsanpes is almost certainly not a dromaeosaurid. So Tom seems to be the start of all this. If this is based off a published work, I have not heard of it. The description specifically states that the metatarsus is unfused however, contradicting Holtz\\\'s statement (but not his conclusion). So, let\\\'s compare this species to basal avians as well as dromaeosaurs to see if there is any additional support for avian relations. Osmolska allied this species with dromaeosaurids, but noted it resembled troodontids in the narrow metatarsus and weakly developed second pedal digit. He dismissed avian origins based on the lack of fusion.
The non-arctometatarsalian pes agrees with both dromaeosaurs and basal avians, but it is less constricted proximally than either Deinonychus, Velociraptor, Rahonavis or Archaeopteryx, instead expanding slightly as in Yandangornis, confuciusornithids, enantiornithines and Patagopteryx. The posteriorly concave metatarsus is absent in Velociraptor and Mononykus, present in some enantiornithines, Patagopteryx and Vorona, but in Elmisaurus as well, so this isn\\\'t neccessarily an avian character. The second digit was clearly hyperextendable, based on the dorsally extended articulation on phalanx II-1.
This is of course present in dromaeosaurids and Rahonavis, has been advocated for Archaeopteryx and Patagopteryx, but is absent in Confuciusornis. Hulsanpes certainly lacks the ornithurine character of \\\"proximal end of metatarsal III displaced plantarily compared to other metatarsals\\\". Hulsanpes also lacks the enantiornithine character of \\\"strongly reduced metatarsal IV\\\", though this is only verified to my knowledge in American specimens and Concornis. So Hulsanpes is a member of the Yandangornis + Pygostylia clade based on the proximally expanded third metatarsal, but not an enantiornithine or ornithurine (although comparisons with Asian enantiornithines would be useful).
This leaves Yandangornis, confuciusornithids, Vorona and Patagopteryx as possible close relatives. Perhaps Hulsanpes is just basal to the Yandangornis + Pygostylia clade, based on the lack of fusion, or it may be due to the juvenile age of the specimen. Hulsanpes appears to resemble Vorona and Patagopteryx more than confuciusornithids based on the presence of a ginglymoideal articulation on metatarsal II. Data for Yandangornis is lacking. So I recommend referring Hulsanpes to the Yandangornis + Pygostylia group, but excluding it from the Ornithurae and provisionally the Enantiornithes.
Reference
Osmolska, 1982. Hulsanpes perlei n. g. n. sp. (Deinonychosauria, Saurischia, Dinosauria) from the Upper Cretaceous Barun Goyot Formation of Mongolia. Neues Jahrbuch fur Geologie und Palaeontologie, Monatshefte 1982(7), pp 440-448
Osmolska, 1982
Time
Cretaceous Late Campanian
Classification
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora Dromaeosauridae
Diet
Carnivore
Fossilsite
Barun Goyot Formation, Khulsan, Mongolia
Info
Genus - Typespecies
Comments by Mickey Mortimer
Etymology
\\\"Perle\\\'s Khulsan foot\\\", Altangerel Perle being a paleontologist and Khulsan being the Mongolian locality where it was discovered. mid Campanian, Late Cretaceous Barun Goyot Formation, Mongolia
Holotype
(ZPAL MgD-I/173) (juvenile) (30-40 cm) otico-occipital fragment, metatarsal II (~34 mm), phalanx II-1 (~6.5 mm), proximal phalanx II-2, metatarsal III (~39 mm), proximal phalanx III-1, metatarsal IV (~36 mm) Diagnosis- metatarsal III flattens and widens to overlap metatarsal II in anterior view.
Description
This specimen was discovered in 1970 and described twelve years later. Using Confuciusornis and Yandangornis as guides, we can estimate Hulsanpes was about 30-40 cm long, but it was juvenile based on the rough bone texture and the badly abraded articular joints. The metatarsus \\\"lacks even incipient fusion\\\" (contra Holtz), and is non-arctometatarsalian to the point that metatarsal III expands proximally. It is fairly slender and metatarsal III is slightly more robust than the others. Distally, metatarsal III flattens and widens to partially overlap metatarsal II.
The metatarsus is concave posteriorly, with metatarsal III inset compared to the others. The distal end of metatarsal III is shallowly grooved with a symmetrical ginglymus. The distal end of metatarsal IV is transversely flattened and diverges from metatarsal III. The articular surface is narrow and undivided, with a groove posterior to it. Pedal phalanx I-1 is rather similar to Deinonychus. The proximal end has an elongate articular surface divided asymmetrically by a ridge, showing that the articulation of metatarsal II was ginglymoid.
The distal end is divided asymmetrically by a long groove that extends more dorsally than ventrally. The medial condyle is a bit wider and lower. The ligamental fossae are deep and the lateral one is more centrally placed. Although the second digit could apparently hyperextend, the proximoventral heel of phalanx II-2 was not well-developed.
Relationships
First of all, let\\\'s try to figure out why Hulsanpes has been connected to birds lately. Tom Holtz wrote in September of 1995 that the metatarsals and distal tarsals are fused at least distally in this species, like birds. He also cryptically said \\\"future work may show why this is no surprise....\\\".
Then in May of 1997, Tom said that Hulsanpes is almost certainly not a dromaeosaurid. So Tom seems to be the start of all this. If this is based off a published work, I have not heard of it. The description specifically states that the metatarsus is unfused however, contradicting Holtz\\\'s statement (but not his conclusion). So, let\\\'s compare this species to basal avians as well as dromaeosaurs to see if there is any additional support for avian relations. Osmolska allied this species with dromaeosaurids, but noted it resembled troodontids in the narrow metatarsus and weakly developed second pedal digit. He dismissed avian origins based on the lack of fusion.
The non-arctometatarsalian pes agrees with both dromaeosaurs and basal avians, but it is less constricted proximally than either Deinonychus, Velociraptor, Rahonavis or Archaeopteryx, instead expanding slightly as in Yandangornis, confuciusornithids, enantiornithines and Patagopteryx. The posteriorly concave metatarsus is absent in Velociraptor and Mononykus, present in some enantiornithines, Patagopteryx and Vorona, but in Elmisaurus as well, so this isn\\\'t neccessarily an avian character. The second digit was clearly hyperextendable, based on the dorsally extended articulation on phalanx II-1.
This is of course present in dromaeosaurids and Rahonavis, has been advocated for Archaeopteryx and Patagopteryx, but is absent in Confuciusornis. Hulsanpes certainly lacks the ornithurine character of \\\"proximal end of metatarsal III displaced plantarily compared to other metatarsals\\\". Hulsanpes also lacks the enantiornithine character of \\\"strongly reduced metatarsal IV\\\", though this is only verified to my knowledge in American specimens and Concornis. So Hulsanpes is a member of the Yandangornis + Pygostylia clade based on the proximally expanded third metatarsal, but not an enantiornithine or ornithurine (although comparisons with Asian enantiornithines would be useful).
This leaves Yandangornis, confuciusornithids, Vorona and Patagopteryx as possible close relatives. Perhaps Hulsanpes is just basal to the Yandangornis + Pygostylia clade, based on the lack of fusion, or it may be due to the juvenile age of the specimen. Hulsanpes appears to resemble Vorona and Patagopteryx more than confuciusornithids based on the presence of a ginglymoideal articulation on metatarsal II. Data for Yandangornis is lacking. So I recommend referring Hulsanpes to the Yandangornis + Pygostylia group, but excluding it from the Ornithurae and provisionally the Enantiornithes.
Reference
Osmolska, 1982. Hulsanpes perlei n. g. n. sp. (Deinonychosauria, Saurischia, Dinosauria) from the Upper Cretaceous Barun Goyot Formation of Mongolia. Neues Jahrbuch fur Geologie und Palaeontologie, Monatshefte 1982(7), pp 440-448