I assume this is supposed to be the southwest U.S. during the Late Triassic, but there is a hodge-podge of animals from different ages. Still pretty cool though; however, I wish the aetosaur and photosaur were on the scene a little longer, and where is the ubiquitous Postosuchus?
http://www.discovery.com/video-topics/other/dinosaur-videos/triassic-period-reptiles-rule.htm
Showing posts with label reconstructions. Show all posts
Showing posts with label reconstructions. Show all posts
Postosuchus v.2.0 by Jeff Martz
I think this is one of the most amazing reconstructions he has done and is completely revamped from his previous version. Look at the details! I won't comment about the stance for once.
Jeff, when are the posters and T-shirts coming out?
Jeff, when are the posters and T-shirts coming out?
Rioarribasuchus chamaensis Reconstruction
Here is Jeff Martz's recent reconstruction of the aetosaur Rioarribasuchus chamaensis.
His reconstruction is a little different than the one in my 2007 paper. He felt that in the original reconstruction I had the paramedian plates with the pronounced spines too far forward and after much discussion I concur.
I think that this new reconstruction is probably fairly accurate given what we know about Rioarribasuchus and other paratypothoracisin aetosaurs, and it contrasts strongly from other reconstructions that still portray it as a Desmatosuchus-like aetosaur. This relationship was refuted by phylogenetic analysis, and although I really like Matt Celeskey's artwork, the reconstruction as a desmatosuchine is not based upon any actually recovered fossil material. All of the osteoderms with spines in the Rioarribasuchus type material are paramedian plates from the caudal region and nothing homologous with the cervical lateral spines in Desmatosuchus are known.
REFERENCE
Parker, W. G. 2007. Reassessment of the Aetosaur 'Desmatosuchus' chamaensis with a
reanalysis of the phylogeny of the Aetosauria (Archosauria: Pseudosuchia). Journal of Systematic Palaeontology 5:41-68. DOI: 10.1017/S1477201906001994
I think that this new reconstruction is probably fairly accurate given what we know about Rioarribasuchus and other paratypothoracisin aetosaurs, and it contrasts strongly from other reconstructions that still portray it as a Desmatosuchus-like aetosaur. This relationship was refuted by phylogenetic analysis, and although I really like Matt Celeskey's artwork, the reconstruction as a desmatosuchine is not based upon any actually recovered fossil material. All of the osteoderms with spines in the Rioarribasuchus type material are paramedian plates from the caudal region and nothing homologous with the cervical lateral spines in Desmatosuchus are known.
REFERENCE
Parker, W. G. 2007. Reassessment of the Aetosaur 'Desmatosuchus' chamaensis with a
reanalysis of the phylogeny of the Aetosauria (Archosauria: Pseudosuchia). Journal of Systematic Palaeontology 5:41-68. DOI: 10.1017/S1477201906001994
The Ex-Ornithischian Revueltosaurus callenderi
Lukas Panzarin guessed correctly. The reconstruction below is of the Late Triassic pseudosuchian Revueltosaurus callenderi courtesy of Jeff Martz. The new reconstruction is based on new material of this taxon from the Chinle Formation of Petrified Forest National Park.
For those readers not familiar with Revueltosaurus, it was named in 1989 by Adrian Hunt based on isolated teeth from near Revuelto Creek in east-central New Mexico (Bull Canyon Formation of the Dockum Group). The teeth are highly distinctive, leaf-shaped with denticles, and very similar to the teeth of basal ornithischians. Based on these similarities Hunt (1989) tentatively referred Revueltosaurus to the Ornithischia. Below are teeth of Revueltosaurus from Petrified Forest National Park.
However, although no non-dental material of Revueltosaurus was yet known Hunt and Lucas (1994) did consider it to be a bona-fide Ornithischian. Furthermore, these authors erected several other "Ornithischian" taxa from North America based solely on teeth. Heckert (2002) fully redescribed the holotype material and also erected a second species, Revueltosaurus hunti, also based on isolated teeth. As a result, the entire Late Triassic ornithischian record from Narth America and Europe was based solely on isolated teeth. Below is a reconstruction of a hypothesized basal ornithischian.
In 2004 I discovered skeletal material of R. callenderi from the Petrified Forest Member (Chinle Formation) of Petrified Forest National Park. This amazing site (named the Revueltosaurus Quarry) has provided hundreds of bones of numerous individuals of R. callenderi. This was the first recognized non-dental material of this taxon. Below are Randy Irmis, Lori Browne, and Jeff Martz initially excavating the site in 2004.
In 2005 we published a preliminary description of this material. Interestingly the recovered skeletons were not of an ornithischian, or even a dinosaur, but rather from a crocodile-line archosaur (Pseudosuchia). Amazingly, the ornithischian-like dentition was simply a convergence. We argued that none of the North American and European teeth could be unambiguously considered to represent ornithischians. Thus, the entire Late Triassic record of ornithischians from these continents was essentially erased. Below is a cladogram showing the revised position of Revueltosaurus.
A few authors (e.g., Heckert, 2005) have argued against this interpretation, insisting that some of these teeth do represent ornithischians; however, there are no clear characters of these teeth that support this interpretation (Irmis et al, 2007).
In 2006 the Revueltosaurus Quarry yielded a superbly preserved almost complete skeleton of R. callenderi, which I featured at a recent Society of Vertebrate Paleontology meeting. A full description of this specimen (and thus the taxon) is almost complete. One really neat character (I think) apparent in Jeff's reconstruction is the large size of the skull in relation to the postcranial skeleton. The skull is quite a bit longer than the femur, and this is a bit odd considering the skull "accomplishes" this without elongating the forward portion of the skull as in champsosaurids, phytosaurs, and crocodiles.
I have jokingly refered to Revueltosaurus as the "duck-billed platypus" of the Triassic because of its ornithichian-like dentition, aetosaur-like armor carapace, and other characteristics found only in rauisuchians and crocodylomorphs.
Indeed Revueltosaurus belongs to a previously unrecognized clade of archosaur, which hopefully will elucidate phylogentic relationships within Pseudosuchia.
By the way...the PDF of Parker et al (2005) is freely available from the link in the reference below.
REFERENCES
Heckert, A. B. 2002 A revision of the Upper Triassic ornithischian dinosaur Revueltosaurus, with a description of a new species. New Mexico Museum of Natural History and Science Bulletin 21:253–267.
Heckert, A.B. 2005. Krzyzanowskisaurus, a new name for a probable ornithischian dinosaur from the Upper Triassic Chinle Group, Arizona and New Mexico, USA. New Mexico Museum of Natural History and Science Bulletin 29: 77-83.
Hunt, A. P. 1989. A new ?ornithischian dinosaur from the Bull Canyon Formation (Upper Triassic) of east-central New Mexico. pp. 355–358 in Dawn of the age of dinosaurs in the American Southwest (ed. S. G. Lucas & A. P. Hunt). New Mexico Museum of Natural History, Albuquerque, NM.
Hunt, A. P., and S.G. Lucas. 1994. Ornithischian dinosaurs from the Upper Triassic of the United States. pp. 227–241 in In the Shadows of the Dinosaurs: Early Mesozoic Tetrapods (ed. N. C. Fraser & H.-D. Sues). Cambridge University Press.
Irmis, R.B., Parker, W.G., Nesbitt, S.J., and Liu, J. 2006. Early ornithischian dinosaurs: the Triassic record. Historical Biology 19:3-22.
Parker, W.G., Irmis, R.B., Nesbitt, S.J., Martz, J.W., and L.S. Browne. 2005. The Late Triassic pseudosuchian Revueltosaurus callenderi and its implications for the diversity of early ornithischian dinosaurs. Proceedings of the Royal Society B 272:963-969. doi:10.1098/rspb.2004.3047
For those readers not familiar with Revueltosaurus, it was named in 1989 by Adrian Hunt based on isolated teeth from near Revuelto Creek in east-central New Mexico (Bull Canyon Formation of the Dockum Group). The teeth are highly distinctive, leaf-shaped with denticles, and very similar to the teeth of basal ornithischians. Based on these similarities Hunt (1989) tentatively referred Revueltosaurus to the Ornithischia. Below are teeth of Revueltosaurus from Petrified Forest National Park.
However, although no non-dental material of Revueltosaurus was yet known Hunt and Lucas (1994) did consider it to be a bona-fide Ornithischian. Furthermore, these authors erected several other "Ornithischian" taxa from North America based solely on teeth. Heckert (2002) fully redescribed the holotype material and also erected a second species, Revueltosaurus hunti, also based on isolated teeth. As a result, the entire Late Triassic ornithischian record from Narth America and Europe was based solely on isolated teeth. Below is a reconstruction of a hypothesized basal ornithischian.
In 2004 I discovered skeletal material of R. callenderi from the Petrified Forest Member (Chinle Formation) of Petrified Forest National Park. This amazing site (named the Revueltosaurus Quarry) has provided hundreds of bones of numerous individuals of R. callenderi. This was the first recognized non-dental material of this taxon. Below are Randy Irmis, Lori Browne, and Jeff Martz initially excavating the site in 2004.
In 2005 we published a preliminary description of this material. Interestingly the recovered skeletons were not of an ornithischian, or even a dinosaur, but rather from a crocodile-line archosaur (Pseudosuchia). Amazingly, the ornithischian-like dentition was simply a convergence. We argued that none of the North American and European teeth could be unambiguously considered to represent ornithischians. Thus, the entire Late Triassic record of ornithischians from these continents was essentially erased. Below is a cladogram showing the revised position of Revueltosaurus.A few authors (e.g., Heckert, 2005) have argued against this interpretation, insisting that some of these teeth do represent ornithischians; however, there are no clear characters of these teeth that support this interpretation (Irmis et al, 2007).In 2006 the Revueltosaurus Quarry yielded a superbly preserved almost complete skeleton of R. callenderi, which I featured at a recent Society of Vertebrate Paleontology meeting. A full description of this specimen (and thus the taxon) is almost complete. One really neat character (I think) apparent in Jeff's reconstruction is the large size of the skull in relation to the postcranial skeleton. The skull is quite a bit longer than the femur, and this is a bit odd considering the skull "accomplishes" this without elongating the forward portion of the skull as in champsosaurids, phytosaurs, and crocodiles.
I have jokingly refered to Revueltosaurus as the "duck-billed platypus" of the Triassic because of its ornithichian-like dentition, aetosaur-like armor carapace, and other characteristics found only in rauisuchians and crocodylomorphs.
Indeed Revueltosaurus belongs to a previously unrecognized clade of archosaur, which hopefully will elucidate phylogentic relationships within Pseudosuchia.
By the way...the PDF of Parker et al (2005) is freely available from the link in the reference below.
REFERENCES
Heckert, A. B. 2002 A revision of the Upper Triassic ornithischian dinosaur Revueltosaurus, with a description of a new species. New Mexico Museum of Natural History and Science Bulletin 21:253–267.
Heckert, A.B. 2005. Krzyzanowskisaurus, a new name for a probable ornithischian dinosaur from the Upper Triassic Chinle Group, Arizona and New Mexico, USA. New Mexico Museum of Natural History and Science Bulletin 29: 77-83.
Hunt, A. P. 1989. A new ?ornithischian dinosaur from the Bull Canyon Formation (Upper Triassic) of east-central New Mexico. pp. 355–358 in Dawn of the age of dinosaurs in the American Southwest (ed. S. G. Lucas & A. P. Hunt). New Mexico Museum of Natural History, Albuquerque, NM.
Hunt, A. P., and S.G. Lucas. 1994. Ornithischian dinosaurs from the Upper Triassic of the United States. pp. 227–241 in In the Shadows of the Dinosaurs: Early Mesozoic Tetrapods (ed. N. C. Fraser & H.-D. Sues). Cambridge University Press.
Irmis, R.B., Parker, W.G., Nesbitt, S.J., and Liu, J. 2006. Early ornithischian dinosaurs: the Triassic record. Historical Biology 19:3-22.
Parker, W.G., Irmis, R.B., Nesbitt, S.J., Martz, J.W., and L.S. Browne. 2005. The Late Triassic pseudosuchian Revueltosaurus callenderi and its implications for the diversity of early ornithischian dinosaurs. Proceedings of the Royal Society B 272:963-969. doi:10.1098/rspb.2004.3047
Triassic Critter Reconstructions
Here is one of my favorite Triassic critter reconstructions done recently by Jeff Martz. Any ideas on what it is?
Note: Anyone who has already seen this please refrain from answering for a bit. Thanks.
Note: Anyone who has already seen this please refrain from answering for a bit. Thanks.
New Triassic Critter Reconstruction II
Here is another new Late Triassic critter reconstraction from the Chinle/Dockum courtesy of Jeff Martz. As with the last one I'll leave the ID up to you with discussion to follow.
New Triassic Critter Reconstructions
Not only is Jeff Martz a really good geologist and paleontologist he also is very skilled as an illustrator (check out his M.S. thesis Martz [2002], his skeletal reconstruction of Desmatosuchus [from Parker, 2008], and this link at Discovery News for other examples of his work). Jeff has recently initiated a new series of Late Triassic animal reconstructions from Petrified Forest National Park and has generously offered to let me share some of them on my site rather than showing them on his site. The park has been sorely lacking up-to-date reconstructions of many of its Triassic animals, as most existing reconstructions date from the 1980s and do not include the majority of new finds. This is the first of the series and I won't tell you what taxon this is. Instead I'll leave to you to guess its identity. 
These represent slightly different reconstructions of the same animal. It is challenging to try to provide realistic yet thought provoking reconstructions, especially regarding skin color, texture, and soft tissue. The coloration and patterning of most animals fall into a few broad catagories including camouflage, disruptive patterning, and/or sexual display. The animal featured here is most likely a carnivore and thus was provided with more of a disruptive pattern that would allow the animal a mechanism to distract prey by making the body outline hard to see, and thus distance and speed difficult to judge. The upper reconstruction adds hypothesized soft parts including a 'dewlap' and other features which may or may not have been present, and thus are speculative yet feasible for display.
As long as Jeff is willing, I hope to provide more of these new reconstructions in the future.
REFERENCES
Martz, J.W. 2002. The morphology and ontogeny of Typothorax coccinarum (Archosauria, Stagonolepididae) from the upper triassic of the American Southwest. Unpublished M.S. thesis. Texas Tech University, Lubbock.
Parker, W.G. 2008. Description of new material of the aetosaur Desmatosuchus spurensis (Archosauria: Suchia) from the Chinle Formation of Arizona and a revision of the genus Desmatosuchus. PaleoBios , 28:1-40.
These represent slightly different reconstructions of the same animal. It is challenging to try to provide realistic yet thought provoking reconstructions, especially regarding skin color, texture, and soft tissue. The coloration and patterning of most animals fall into a few broad catagories including camouflage, disruptive patterning, and/or sexual display. The animal featured here is most likely a carnivore and thus was provided with more of a disruptive pattern that would allow the animal a mechanism to distract prey by making the body outline hard to see, and thus distance and speed difficult to judge. The upper reconstruction adds hypothesized soft parts including a 'dewlap' and other features which may or may not have been present, and thus are speculative yet feasible for display.
As long as Jeff is willing, I hope to provide more of these new reconstructions in the future.
REFERENCES
Martz, J.W. 2002. The morphology and ontogeny of Typothorax coccinarum (Archosauria, Stagonolepididae) from the upper triassic of the American Southwest. Unpublished M.S. thesis. Texas Tech University, Lubbock.
Parker, W.G. 2008. Description of new material of the aetosaur Desmatosuchus spurensis (Archosauria: Suchia) from the Chinle Formation of Arizona and a revision of the genus Desmatosuchus. PaleoBios , 28:1-40.
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