Post by Derdadort on Aug 2, 2013 19:33:57 GMT 5
Holotype of Stenopelix valdensis and interpretive drawing of the fossil
(c) Richard J. Butler and Robert M. Sullivan under the Creative Commons Attribution 2.0 Generic license
Classification
Dinosauria
Ornithischia
Marginocepahlia(?)
Ceratopsia(?)
Stenopelix valdensis (Meyer, 1859)
Fossilsite: Obernkirchen Sandstone, Niedersachsen (Germany)
Age: 145-139,5 million years (Berriasium, Lower Cretaceous)
Holotype: GZG 741/2
Description
Stenopelix valdensis ("narrow pelvis from Wealden") was a species of small Ornithischia from the early Cretaceous of Northwestern Germany. It reached a total lenght of about 1,5m and walked probably mainly on its hind limbs.The holotype and only known specimen is in fact shorter than one metre and suggested to be a subadult. Despite the missing skull Stenopelix was most likely a herbivour.
Systematics
The holotype consists of great parts of the postcranial skeleton, neck and skull are missing and many bones had to be destroyed during preparation, however there some replica made of latex. So it's difficult to classify Stenopelix clearly and its affiliation is controversial discussed. For the last decades it was thought to be a Pachycepahlosaurian. This was inter alia supported by the long anterior caudal rips, the exclusion of the pubis from the acetaculum and the tibia, which is shorter than the femur. However, in 2009 Butler et al. showed that those features are indeed a weak evidence for pachycepahlosaurian identity, because they're misinterpretated or also found in non-pachycephalosaurian Ornithischians. Furthermore other pachycephalosaurian features are completly missing in Stenopelix.
S.valdensis very likely belongs to Cerapoda, probably to Marginocephalia.(Butler 2009)
Two years later (2011) a cladistic analysis of Butler et al. showed that Stenopelix is the sister taxon of Yinlong and therefore a primitive ceratopsian.*
Yinlong, probably the sister taxon of Stenopelix
(c) Nobu Tamura under the Creative Commons Attribution 3.0 Unported license
* uncertain, I have no access to the paper
Sources:
1) Richard J. Butler, Robert R. Sullivan, "The phylogenetic position of the ornithischian dinosaur Stenopelix valdensis from the Lower Cretaceous of Germany and the early fossil record of Pachycephalosauria", 2009
2) Thomas R. Holtz, HoltzappendixWinter2011.pdf
3) onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2011.01046.x/abstract
(c) Richard J. Butler and Robert M. Sullivan under the Creative Commons Attribution 2.0 Generic license
Classification
Dinosauria
Ornithischia
Marginocepahlia(?)
Ceratopsia(?)
Stenopelix valdensis (Meyer, 1859)
Fossilsite: Obernkirchen Sandstone, Niedersachsen (Germany)
Age: 145-139,5 million years (Berriasium, Lower Cretaceous)
Holotype: GZG 741/2
Description
Stenopelix valdensis ("narrow pelvis from Wealden") was a species of small Ornithischia from the early Cretaceous of Northwestern Germany. It reached a total lenght of about 1,5m and walked probably mainly on its hind limbs.The holotype and only known specimen is in fact shorter than one metre and suggested to be a subadult. Despite the missing skull Stenopelix was most likely a herbivour.
Systematics
The holotype consists of great parts of the postcranial skeleton, neck and skull are missing and many bones had to be destroyed during preparation, however there some replica made of latex. So it's difficult to classify Stenopelix clearly and its affiliation is controversial discussed. For the last decades it was thought to be a Pachycepahlosaurian. This was inter alia supported by the long anterior caudal rips, the exclusion of the pubis from the acetaculum and the tibia, which is shorter than the femur. However, in 2009 Butler et al. showed that those features are indeed a weak evidence for pachycepahlosaurian identity, because they're misinterpretated or also found in non-pachycephalosaurian Ornithischians. Furthermore other pachycephalosaurian features are completly missing in Stenopelix.
S.valdensis very likely belongs to Cerapoda, probably to Marginocephalia.(Butler 2009)
Two years later (2011) a cladistic analysis of Butler et al. showed that Stenopelix is the sister taxon of Yinlong and therefore a primitive ceratopsian.*
Yinlong, probably the sister taxon of Stenopelix
(c) Nobu Tamura under the Creative Commons Attribution 3.0 Unported license
* uncertain, I have no access to the paper
Sources:
1) Richard J. Butler, Robert R. Sullivan, "The phylogenetic position of the ornithischian dinosaur Stenopelix valdensis from the Lower Cretaceous of Germany and the early fossil record of Pachycephalosauria", 2009
2) Thomas R. Holtz, HoltzappendixWinter2011.pdf
3) onlinelibrary.wiley.com/doi/10.1111/j.1475-4983.2011.01046.x/abstract