Wow, the free PDFs just keep coming. Thanks to Paul Heinrich who posted this information on the Dinosaur Mailing List.
"For an unknown period of time free PDF files of papers published in "Geology" and "Geological Society of America Bulletin" can be downloaded free of charge.
A person can access them using the search page at:
http://gsabulletin.gsapubs.org/search.dtl
and the archive pages at:
http://gsabulletin.gsapubs.org/archive/
and
http://geology.gsapubs.org/archive/"
I checked it out and it works.
Happy Downloading.
New Pterosaur Volume Honoring Peter Wellnhofer Now Available
NOW AVAILABLE...
Flugsaurier: Pterosaur papers in honour of Peter Wellnhofer. 2008. Hone, D.W.E., and Buffetaut, E. (eds). Zitteliana B 28. 264pp.
CONTENTS...
Wellnhofer, P. A short history of pterosaur research. p7-19.
Padian, K. Were pterosaur ancestors bipedal or quadrupedal?: Morphometric, functional and phylogenetic considerations. p21-33.
Hone, DW.E., & Benton, M.J. Contrasting supertrees and total-evidence methods: pterosaur origins. p35-60.
Barrett, P.M., Butler, R.J., Edwards, N.P., & Milner, A.R. Pterosaur distribution in time and space: an atlas. p61-107.
Steel, L. The palaeohistology of pterosaur bone: an overview. p109-125.
Bennett, S.C. Morphological evolution of the wing of pterosaurs: mycology and function. p127-141.
Witton, M.P. A new approach to determining pterosaur body mass and its implications for pterosaur flight. p143-159.
Habaib, M.B. Comparative evidence for quadrupedal launch in pterosaurs. p161-168.
Elgin, R.E., Grau, C.A., Palmer, C., Hone, D.W.E., Greenwell, D., & Benton, M.J. Aerodynamic characters of the cranial crest in Pteranodon. p169-176.
Martill, D.M., & Witton, M.P. Catastrophic failure in a pterosaur skull from the Cretaceous Santana Formation of Brazil. p177-185.
Lockley, M., Harris, J.D., & Mirchell, L. A golobal overview of pterosaur ichnology: tracksite distribution in space and time. p187-198.
Unwin, D.M., & D.C. Deeming. Pterosaur eggshell structure and its implications for pterosaur reproductive biology. p199-207.
Martill, D.M., Witton, M.P., & Gale, A. Possible azhdarchoid remains from the Coniacian (Late Cretaceous) of England. p209-218.
Rodrigues, T., & Kellner, A.W.A. Review of the pterodactyloid pterosaur Coloborhynchus. p210-228.
Lu, J., Xu, L., & Ji, Q. Restudy of Liaoxipterus (Istiodactylidae: Pterosauria) with comments on the Chinese istiodactylid pterosaurs. p229-241.
Martill, D.M. First pterosaur remains from Exu Formation (Cretaceous) from the Araripe Basin, Brazil. p243-248.
Buffetaut, E. Late Cretaceous pterosaurs from France: a review. p249-255.
ORDERING INFO...
According to David Hone anyone who wants to order it should contact the publishers. The price is 29 Euros (plus postage). The volumes are still being printed and will be shipped around the end of January.
Contact:
Andreas TrenkleJörg-Tömlinger-Str. 2D-82152 PlaneggGermany Fax ++49-89-89329763 (inside Germany: 089-89329763)email: andreas@trenkle-buch.de
Please note that at this time the publisher does not accept credit cards.
Flugsaurier: Pterosaur papers in honour of Peter Wellnhofer. 2008. Hone, D.W.E., and Buffetaut, E. (eds). Zitteliana B 28. 264pp.
CONTENTS...
Wellnhofer, P. A short history of pterosaur research. p7-19.
Padian, K. Were pterosaur ancestors bipedal or quadrupedal?: Morphometric, functional and phylogenetic considerations. p21-33.
Hone, DW.E., & Benton, M.J. Contrasting supertrees and total-evidence methods: pterosaur origins. p35-60.
Barrett, P.M., Butler, R.J., Edwards, N.P., & Milner, A.R. Pterosaur distribution in time and space: an atlas. p61-107.
Steel, L. The palaeohistology of pterosaur bone: an overview. p109-125.
Bennett, S.C. Morphological evolution of the wing of pterosaurs: mycology and function. p127-141.
Witton, M.P. A new approach to determining pterosaur body mass and its implications for pterosaur flight. p143-159.
Habaib, M.B. Comparative evidence for quadrupedal launch in pterosaurs. p161-168.
Elgin, R.E., Grau, C.A., Palmer, C., Hone, D.W.E., Greenwell, D., & Benton, M.J. Aerodynamic characters of the cranial crest in Pteranodon. p169-176.
Martill, D.M., & Witton, M.P. Catastrophic failure in a pterosaur skull from the Cretaceous Santana Formation of Brazil. p177-185.
Lockley, M., Harris, J.D., & Mirchell, L. A golobal overview of pterosaur ichnology: tracksite distribution in space and time. p187-198.
Unwin, D.M., & D.C. Deeming. Pterosaur eggshell structure and its implications for pterosaur reproductive biology. p199-207.
Martill, D.M., Witton, M.P., & Gale, A. Possible azhdarchoid remains from the Coniacian (Late Cretaceous) of England. p209-218.
Rodrigues, T., & Kellner, A.W.A. Review of the pterodactyloid pterosaur Coloborhynchus. p210-228.
Lu, J., Xu, L., & Ji, Q. Restudy of Liaoxipterus (Istiodactylidae: Pterosauria) with comments on the Chinese istiodactylid pterosaurs. p229-241.
Martill, D.M. First pterosaur remains from Exu Formation (Cretaceous) from the Araripe Basin, Brazil. p243-248.
Buffetaut, E. Late Cretaceous pterosaurs from France: a review. p249-255.
ORDERING INFO...
According to David Hone anyone who wants to order it should contact the publishers. The price is 29 Euros (plus postage). The volumes are still being printed and will be shipped around the end of January.
Contact:
Andreas TrenkleJörg-Tömlinger-Str. 2D-82152 PlaneggGermany Fax ++49-89-89329763 (inside Germany: 089-89329763)email: andreas@trenkle-buch.de
Please note that at this time the publisher does not accept credit cards.
Conodonts Squished by Thoughtless Dinosaurs
The 52nd annual meeting of the Palaeontological Association was held in December 2008 in the University of Glasgow. Although I was unable to attend (someday I will) the following poster presentation caught my eye. Probably not too many people are experts on World War I tunnels, stromatolites, conodonts, dinosaurs, and archosaur trackways but here is where all of these fields finally collide....
Belvedere, M., Mietto, P., Avanzini, M., and M. Rigo. 2008. Dinosaurs stepping on the conodont animals; p. 44 in Programme and Abstracts for the 52nd meeting of the Palaeontological Association. The Palaeontological Association Newsletter 69.
On the roof of a First World War tunnel in the Monte Pasubio (North Eastern Italy), on a supratidal stromatolitic bed of the Dolomia Principale Formation, 11 tracks have been found. Among them occur some clear dinosaurian tridactyl footprints, from small grallatorid-like to medium-large eubrontid, as well as some tetradactyl footprints. This formation contains the principal dinosaur footprints for the Triassic of the southern alps. All previous findings were on fallen blocks which, given the poor paleontological content of the formation, and the lack of precise stratigraphical position, made their biostratigraphical constraints very difficult to determine. In this case, for the first time, the trampled surface crops out in situ, about 500m from the bottom of the formation. Conodont sampling was carried out on the subtidal level just below the trampled surface. Unexpectedly, two conodonts were found: an advanced Epigondolella praeslovakensis and a true Mockina slovakensis, an association exclusive for the Middle Norian (latest Alaunian). Thus being so precisely contrained, the ichnoassociation could be used to date the other isolated blocks of the Dolomites. Moreover this co-occurrence of tetrpod footprints and conodonts can be used to confirm the Middle Norian age of the Eubrontes-Grallator biochron.
Dinosaur skeletons covered with ammonites have been found in marine strata , but as the authors state this is a first for conodonts and footprints. It's too bad that this does not happen more often to tie together marine and non-marine biostratigraphies. By the way, the small tridactyl tracks probably are ornithodiran as no self respecting pseudosuchian would stomp on conodonts ;).
Belvedere, M., Mietto, P., Avanzini, M., and M. Rigo. 2008. Dinosaurs stepping on the conodont animals; p. 44 in Programme and Abstracts for the 52nd meeting of the Palaeontological Association. The Palaeontological Association Newsletter 69.
On the roof of a First World War tunnel in the Monte Pasubio (North Eastern Italy), on a supratidal stromatolitic bed of the Dolomia Principale Formation, 11 tracks have been found. Among them occur some clear dinosaurian tridactyl footprints, from small grallatorid-like to medium-large eubrontid, as well as some tetradactyl footprints. This formation contains the principal dinosaur footprints for the Triassic of the southern alps. All previous findings were on fallen blocks which, given the poor paleontological content of the formation, and the lack of precise stratigraphical position, made their biostratigraphical constraints very difficult to determine. In this case, for the first time, the trampled surface crops out in situ, about 500m from the bottom of the formation. Conodont sampling was carried out on the subtidal level just below the trampled surface. Unexpectedly, two conodonts were found: an advanced Epigondolella praeslovakensis and a true Mockina slovakensis, an association exclusive for the Middle Norian (latest Alaunian). Thus being so precisely contrained, the ichnoassociation could be used to date the other isolated blocks of the Dolomites. Moreover this co-occurrence of tetrpod footprints and conodonts can be used to confirm the Middle Norian age of the Eubrontes-Grallator biochron.
Dinosaur skeletons covered with ammonites have been found in marine strata , but as the authors state this is a first for conodonts and footprints. It's too bad that this does not happen more often to tie together marine and non-marine biostratigraphies. By the way, the small tridactyl tracks probably are ornithodiran as no self respecting pseudosuchian would stomp on conodonts ;).
My Favorite Kind of News Story
Mesalands Community College professor (and phytosaur expert) Axel Hungerbuehler is finding some great Late Triassic material in the Redonda Formation (Dockum Group) of New Mexico. Obviously I always get excited about the discovery of new aetosaur material.... oh yeah, there is some dinosaur material as well (which, of course, got the headline). Other related stories can be found here and here.
Students discover possible dinosaur fossil
By Thomas Garcia, Freedom New Mexico
January 13, 2009 - 9:21PM
A Mesalands Community College paleontology class has found a fossil that could be of a new form of Triassic reptile at an eastern New Mexico dig site. “I think that we have found a new form of aetosaurs,” said Axel Hungerbuehler, professor of Paleontology at Mesalands Community College.
The aetosaur, or eagle lizard, fossils were among numerous fossils excavated at a site in the Redonda formation in Quay County. Aetosaurs, a heavily armored plant-eater that lived in the Triassic period an estimated 200 Million years ago, are identified by the armor plating on their back and sides. Each of the plates has a distinct pattern and shape, Hungerbuehler said.
“The analysis of the armor plates found at the dig site indicates that we have found a new form of aetosaur,” Hungerbuehler said. In addition to the plates, they have identified bones of the internal skeleton of an aetosaur, including parts of the hip and several leg bones.
So far, however, no complete articulated skeletons have been excavated from the site, Hungerbuehler said.
Several more dinosaur-like elements, including another hip bone (pubis) and several hollow limb bones, were also recovered, Hungerbuehler said.
“These bones are not from the same individual dinosaur that was found in 2007,” Hungerbuehler said. “They could be fossils of a similar type of dinosaur.”
In 2007 a field class found a hip bone (ilium) of an un-named primitive dinosaur that was collected at the Redonda Formation site.
“We have not done enough examination of the fossil to determine if it is a new and previously undiscovered type of primitive dinosaur,” Hungerbuehler said. “A definite identification will be done once these fossils have been freed from their rocky host and they can be carefully cleaned.”
This all started during the summer of 2006, when three field classes and several volunteers of Mesalands Community College’s Dinosaur Museum started excavating bones of reptiles at the current dig site.
Hungerbuehler said an abundance of fossils were found in red and green siltstones, and sandstones of the Upper Triassic estimated to be 200 million years old. To date, about 250 field numbers have been recorded.
At the site they have found that bones occur in two different settings.
• In coarser layers of sandstones, bones are evenly distributed and show signs like breaking and abrasion, indicating they have been washed together by water currents.
• In red, fine-grained siltstones, undamaged bones have been found in spots of dense concentrations.
These probably represent skeletons that fell apart at the spot. Many of the bones still await preparation.
Items identified from the records kept in the field and the bones already freed from the rock in Mesalands Community College’s Dinosaur Museum Lab include:
• Phytosaurs — semiaquatic crocodile-like reptiles - two phytosaur skulls and parts of a large lower jaw were recovered, plus numerous bones of the body.
• Large carnivorous reptile, A large reptile, perhaps, a rauisuchian (Rau’s crocodiles) which includes the largest predators in the Late Triassic, is represented by the tip of a lower jaw. The element is currently under study by students at Mesalands to confirm the identity
Students discover possible dinosaur fossil
By Thomas Garcia, Freedom New Mexico
January 13, 2009 - 9:21PM
A Mesalands Community College paleontology class has found a fossil that could be of a new form of Triassic reptile at an eastern New Mexico dig site. “I think that we have found a new form of aetosaurs,” said Axel Hungerbuehler, professor of Paleontology at Mesalands Community College.
The aetosaur, or eagle lizard, fossils were among numerous fossils excavated at a site in the Redonda formation in Quay County. Aetosaurs, a heavily armored plant-eater that lived in the Triassic period an estimated 200 Million years ago, are identified by the armor plating on their back and sides. Each of the plates has a distinct pattern and shape, Hungerbuehler said.
“The analysis of the armor plates found at the dig site indicates that we have found a new form of aetosaur,” Hungerbuehler said. In addition to the plates, they have identified bones of the internal skeleton of an aetosaur, including parts of the hip and several leg bones.
So far, however, no complete articulated skeletons have been excavated from the site, Hungerbuehler said.
Several more dinosaur-like elements, including another hip bone (pubis) and several hollow limb bones, were also recovered, Hungerbuehler said.
“These bones are not from the same individual dinosaur that was found in 2007,” Hungerbuehler said. “They could be fossils of a similar type of dinosaur.”
In 2007 a field class found a hip bone (ilium) of an un-named primitive dinosaur that was collected at the Redonda Formation site.
“We have not done enough examination of the fossil to determine if it is a new and previously undiscovered type of primitive dinosaur,” Hungerbuehler said. “A definite identification will be done once these fossils have been freed from their rocky host and they can be carefully cleaned.”
This all started during the summer of 2006, when three field classes and several volunteers of Mesalands Community College’s Dinosaur Museum started excavating bones of reptiles at the current dig site.
Hungerbuehler said an abundance of fossils were found in red and green siltstones, and sandstones of the Upper Triassic estimated to be 200 million years old. To date, about 250 field numbers have been recorded.
At the site they have found that bones occur in two different settings.
• In coarser layers of sandstones, bones are evenly distributed and show signs like breaking and abrasion, indicating they have been washed together by water currents.
• In red, fine-grained siltstones, undamaged bones have been found in spots of dense concentrations.
These probably represent skeletons that fell apart at the spot. Many of the bones still await preparation.
Items identified from the records kept in the field and the bones already freed from the rock in Mesalands Community College’s Dinosaur Museum Lab include:
• Phytosaurs — semiaquatic crocodile-like reptiles - two phytosaur skulls and parts of a large lower jaw were recovered, plus numerous bones of the body.
• Large carnivorous reptile, A large reptile, perhaps, a rauisuchian (Rau’s crocodiles) which includes the largest predators in the Late Triassic, is represented by the tip of a lower jaw. The element is currently under study by students at Mesalands to confirm the identity
Relaunch of Stuttgarter Beiträge zur Naturkunde Serie B as the open access journal Palaeodiversity
Thanks to Randy Irmis for bringing this to my attention. The journal Stuttgarter Beiträge zur Naturkunde Serie B has been relaunched as a new open access journal Palaeodiversity. The first issue was released in late 2008 and contains a new paper by Rainer Schoch on the phylogeny of the Capitosauria (the amount of temnospondyl work pubished in 2008 is just amazing!).
Also of great interest is that the journal site is offering free downloads of articles (including some Triassic articles) from back issues of Stuttgarter Beiträge zur Naturkunde Serie from 1999 with a promise that more will follow (www.palaeodiversity.org/backissues.htm).
Schoch, R. R. 2008. The Capitosauria (Amphibia): characters, phylogeny, and stratigraphy. Palaeodiversity 1:189-226.
Abstract - The phylogeny of the largest amphibians, the Triassic capitosaurs, is still much debated. One key taxon for the understanding of their relationships, Odenwaldia heidelbergensis from the Buntsandstein of Waldkatzenbach, is restudied here. A phylogenetic analysis performed on the basis of 66 characters and 25 taxa gives a new hypothesis of relationships. It rests to a large degree on previous data matrices, but many character codings have been changed with respect to new observations as well as the discovery of new taxa. The present data indicate that all classic capitosaur taxa do form a clade. The Capitosauria (all taxa more closely related to Parotosuchus than to Trematosaurus) excludes Benthosuchus and Edingerella but includes Wetlugasaurus, Sclerothorax, Watsonisuchus, Parotosuchus, and all other capitosaurs. All capitosaurs above Watsonisuchus are referred to as the Capitosauroidea, which includes Parotosuchus, Cherninia + Odenwaldia, Eryosuchus, Xenotosuchus, and a vast capitosaur crown clade. The crown includes two main branches: (1) the “Eucyclotosauria” (Cyclotosaurus, Kupferzellia, Procyclotosaurus, Stanocephalosaurus pronus) and (2) the “Paracyclotosauria” (Stanocephalosaurus birdi, Paracyclotosaurus, Mastodonsaurus, and the heylerosaurids Eocyclotosaurus and Quasicyclotosaurus). Stratigraphically, capitosaur phylogeny still reveals a rather poor match. However, the present phylogenetic hypothesis matches the stratigraphic ranges more precisely than the previous ones. The early branching between the “Eucyclotosauria” and “Paracyclotosauria” is more consistent with the fossil record than an alternative concept, in which Cyclotosaurus and the heylerosaurids form sister taxa (“Pancyclotosauria”). In any case, the otic fenestra and several other probably correlated features in the palate must have evolved two times independently within the crown capitosauroids.
Also of great interest is that the journal site is offering free downloads of articles (including some Triassic articles) from back issues of Stuttgarter Beiträge zur Naturkunde Serie from 1999 with a promise that more will follow (www.palaeodiversity.org/backissues.htm).
Schoch, R. R. 2008. The Capitosauria (Amphibia): characters, phylogeny, and stratigraphy. Palaeodiversity 1:189-226.
Abstract - The phylogeny of the largest amphibians, the Triassic capitosaurs, is still much debated. One key taxon for the understanding of their relationships, Odenwaldia heidelbergensis from the Buntsandstein of Waldkatzenbach, is restudied here. A phylogenetic analysis performed on the basis of 66 characters and 25 taxa gives a new hypothesis of relationships. It rests to a large degree on previous data matrices, but many character codings have been changed with respect to new observations as well as the discovery of new taxa. The present data indicate that all classic capitosaur taxa do form a clade. The Capitosauria (all taxa more closely related to Parotosuchus than to Trematosaurus) excludes Benthosuchus and Edingerella but includes Wetlugasaurus, Sclerothorax, Watsonisuchus, Parotosuchus, and all other capitosaurs. All capitosaurs above Watsonisuchus are referred to as the Capitosauroidea, which includes Parotosuchus, Cherninia + Odenwaldia, Eryosuchus, Xenotosuchus, and a vast capitosaur crown clade. The crown includes two main branches: (1) the “Eucyclotosauria” (Cyclotosaurus, Kupferzellia, Procyclotosaurus, Stanocephalosaurus pronus) and (2) the “Paracyclotosauria” (Stanocephalosaurus birdi, Paracyclotosaurus, Mastodonsaurus, and the heylerosaurids Eocyclotosaurus and Quasicyclotosaurus). Stratigraphically, capitosaur phylogeny still reveals a rather poor match. However, the present phylogenetic hypothesis matches the stratigraphic ranges more precisely than the previous ones. The early branching between the “Eucyclotosauria” and “Paracyclotosauria” is more consistent with the fossil record than an alternative concept, in which Cyclotosaurus and the heylerosaurids form sister taxa (“Pancyclotosauria”). In any case, the otic fenestra and several other probably correlated features in the palate must have evolved two times independently within the crown capitosauroids.
Using Detrital Zircons to Reconstruct Chinle Paleogeography
Dickinson, W.R., and G.E. Gehrels. 2008. U-Pb Ages of Detrital Zircons in Relation to Paleogeography: Triassic Paleodrainage Networks and Sediment Dispersal Across Southwest Laurentia. Journal of Sedimentary Research 78:745-764.
Abstract - Integration of detrital zircon studies with data on biostratigraphy, isopachs, facies, and paleocurrents can improve reconstructions of paleogeography for ancient fluvial systems. U-Pb ages for 1808 individual detrital zircon grains in 20 samples of Triassic fluvial sandstone on the Colorado Plateau and High Plains, U.S.A., help constrain paleodrainage paths and patterns of sediment dispersal across southwest Laurentia. The dominant paleoflow was from southeast to northwest from sources as distant as the Ouachita orogen, and segments of Mesoamerica beyond it, to the Cordilleran margin in the Great Basin. Detrital zircons in Middle Triassic Moenkopi strata deposited along the distal eastern flank of the Sonoma foreland basin were derived from varied sources to the south and southeast, as were similar populations of detrital zircons in Upper Triassic Chinle strata exposed along the southern margin of the Colorado Plateau. Basal Chinle (-Dockum) strata of the High Plains to the east contain detrital zircon populations dominated by Cambrian grains derived from the nearby Amarillo–Wichita uplift, as do Gartra strata of northeast Utah to which the Cambrian grains were transported across eroded roots of Ancestral Rocky Mountains uplifts along upstream reaches of the Eagle paleoriver of northwest Colorado. The central locus of the Chinle–Dockum fluvial system lay along the tectonic furrow of an elongate backarc basin formed by dynamic subsidence inland from the Cordilleran magmatic arc. A lower Chinle–Dockum trunk paleoriver and the upper Chinle–Dockum Cottonwood paleovalley document longitudinal paleoflow parallel to the axis of the basin. Detrital zircon populations show that headwaters of both paleodrainages tapped the Ouachita orogen, the Permian–Triassic East Mexico arc, and associated rock assemblages of southwest Laurentia and adjacent Mesoamerica. Sediment sources in the Mesozoic Cordilleran arc became increasingly more prominent during Late Triassic time.
_________________________________________________________________
This is part of an ongoing project to reconstruct Triassic paleogeography using detrital zircons, especially the Chinle-Dockum paleoriver systems. The results reinforce the hypothesis of Riggs et al. (1996) that during early Chinle and Dockum deposition the two basins were linked by a single river system. One aspect of this paper that caught my eye is that the authors acknowledge the current confusion regarding ranks among Chinle-Dockum stratigraphic units, and leave this unresolved. Their results hinge on hypothesized unit correlations (supported in part by detrital zircon provenance), namely that the Sonsela, Poleo, and Trujillo sandstones are equivalents as are the Shinarump, Santa Rosa, and Agua Zarca. However, recent paleomag work by Kate Zeigler has suggested that the Sonsela and Poleo are probably not equivalent (Zeigler et al. 2008) and this work needs to be expanded to the other units. It is important to note however, that the "Sonsela" of Dickinson and Gehrels is only equivalent to a medial sandstone bed (Jasper Forest bed) in the expanded Sonsela Member of the Chinle (see Jeff Martz's detailed discussion of the stratigraphy of the Chinle in Petrified Forest National Park), and that other portions of the member may be Poleo equivalent. Nonetheless, the Dickinson and Gehrels paper is an important part of a plethora of new research projects that are clarifying the stratigraphy, biostratigraphy, and paleogeography of the Chinle and Dockum.
As part of this, I'm excited that the stratigraphic and biostratigraphic work being done in Petrified Forest National Park (and mentioned by Jeff), is being supplemented by paleomag work, isotopic dating, provenance work, chemostratigraphic work, and a host of sedimentological and paleosol studies. As a result of the work in the park and regional studies such as this, we are getting very close to finally being able to put together a detailed paleontological and geological history of the park, which will hopefully serve as a standard for the rest of the American southwest.
REFERENCES
Riggs, N. R., Lehman, T. M., Gehrels, G. E., and W. R. Dickinson. 1996. Detrital zircon link between headwaters and terminus of the Upper Triassic Chinle-Dockum paleoriver system. Science 273:97-100.
Zeigler, K. E., Kelley, S., and J. W. Geissman. 2008. Revisions to stratigraphic nomenclature of the Upper Triassic Chinle Group in New Mexico: New insights from geologic mapping, sedimentology, and magnetostratigraphic/paleomagnetic data. Rocky Mountain Geology 43:121-141.
Abstract - Integration of detrital zircon studies with data on biostratigraphy, isopachs, facies, and paleocurrents can improve reconstructions of paleogeography for ancient fluvial systems. U-Pb ages for 1808 individual detrital zircon grains in 20 samples of Triassic fluvial sandstone on the Colorado Plateau and High Plains, U.S.A., help constrain paleodrainage paths and patterns of sediment dispersal across southwest Laurentia. The dominant paleoflow was from southeast to northwest from sources as distant as the Ouachita orogen, and segments of Mesoamerica beyond it, to the Cordilleran margin in the Great Basin. Detrital zircons in Middle Triassic Moenkopi strata deposited along the distal eastern flank of the Sonoma foreland basin were derived from varied sources to the south and southeast, as were similar populations of detrital zircons in Upper Triassic Chinle strata exposed along the southern margin of the Colorado Plateau. Basal Chinle (-Dockum) strata of the High Plains to the east contain detrital zircon populations dominated by Cambrian grains derived from the nearby Amarillo–Wichita uplift, as do Gartra strata of northeast Utah to which the Cambrian grains were transported across eroded roots of Ancestral Rocky Mountains uplifts along upstream reaches of the Eagle paleoriver of northwest Colorado. The central locus of the Chinle–Dockum fluvial system lay along the tectonic furrow of an elongate backarc basin formed by dynamic subsidence inland from the Cordilleran magmatic arc. A lower Chinle–Dockum trunk paleoriver and the upper Chinle–Dockum Cottonwood paleovalley document longitudinal paleoflow parallel to the axis of the basin. Detrital zircon populations show that headwaters of both paleodrainages tapped the Ouachita orogen, the Permian–Triassic East Mexico arc, and associated rock assemblages of southwest Laurentia and adjacent Mesoamerica. Sediment sources in the Mesozoic Cordilleran arc became increasingly more prominent during Late Triassic time.
_________________________________________________________________
This is part of an ongoing project to reconstruct Triassic paleogeography using detrital zircons, especially the Chinle-Dockum paleoriver systems. The results reinforce the hypothesis of Riggs et al. (1996) that during early Chinle and Dockum deposition the two basins were linked by a single river system. One aspect of this paper that caught my eye is that the authors acknowledge the current confusion regarding ranks among Chinle-Dockum stratigraphic units, and leave this unresolved. Their results hinge on hypothesized unit correlations (supported in part by detrital zircon provenance), namely that the Sonsela, Poleo, and Trujillo sandstones are equivalents as are the Shinarump, Santa Rosa, and Agua Zarca. However, recent paleomag work by Kate Zeigler has suggested that the Sonsela and Poleo are probably not equivalent (Zeigler et al. 2008) and this work needs to be expanded to the other units. It is important to note however, that the "Sonsela" of Dickinson and Gehrels is only equivalent to a medial sandstone bed (Jasper Forest bed) in the expanded Sonsela Member of the Chinle (see Jeff Martz's detailed discussion of the stratigraphy of the Chinle in Petrified Forest National Park), and that other portions of the member may be Poleo equivalent. Nonetheless, the Dickinson and Gehrels paper is an important part of a plethora of new research projects that are clarifying the stratigraphy, biostratigraphy, and paleogeography of the Chinle and Dockum.
As part of this, I'm excited that the stratigraphic and biostratigraphic work being done in Petrified Forest National Park (and mentioned by Jeff), is being supplemented by paleomag work, isotopic dating, provenance work, chemostratigraphic work, and a host of sedimentological and paleosol studies. As a result of the work in the park and regional studies such as this, we are getting very close to finally being able to put together a detailed paleontological and geological history of the park, which will hopefully serve as a standard for the rest of the American southwest.
REFERENCES
Riggs, N. R., Lehman, T. M., Gehrels, G. E., and W. R. Dickinson. 1996. Detrital zircon link between headwaters and terminus of the Upper Triassic Chinle-Dockum paleoriver system. Science 273:97-100.
Zeigler, K. E., Kelley, S., and J. W. Geissman. 2008. Revisions to stratigraphic nomenclature of the Upper Triassic Chinle Group in New Mexico: New insights from geologic mapping, sedimentology, and magnetostratigraphic/paleomagnetic data. Rocky Mountain Geology 43:121-141.
I just gotta say this....
Unlike my colleague Jeff Martz I am not drinking myself into a stupor tonight because of some horrible singer, but reading through a few papers over the last few days has finally pushed me to the edge as well...and like Jeff I need to talk about this.
There are two errors, which should not be, that persistently show up in the Triassic literature. One is relatively minor but annoying, whereas the other is not only annoying but does have implications.
1) For the last 13 years Long and Murry (1995) has likely been the most cited paper for Late Triassic vertebrate paleontology. Prior to this Phillip Murry published quite a few papers dating back to the early 1980s on Triassic paleontology and Geology. His name, although uncommon, has only five letters in it. Why, with a simple name and numerous citations do many people continue to misspell his name (as Murray) in many papers? And why do the reviewers not catch this either? Again, nothing major but just annoying seeing it in paper after paper.
2) Having done my graduate work and published several papers concerning the aetosaur Desmatosuchus, I have noticed and continue to notice that despite being known by good material for over 80 years people continue to incorrectly assign material to this genus. Historically, any robust spiked aetosaur has been assigned to his taxon and that has caused much confusion; however, since 1985 the genus has been diagnosed using in part the ornamentation of its dermal osteoderms. Desmatosuchus is the only aetosaur genus that combines an ornamentation of randomly placed pits and grooves (with no radial patterning at all), a depressed anterior lamina (a smooth area of the osteoderm that underlies the preceding plate), and a centrally placed dorsal boss. This has been repeated numerous times in the literature yet I constantly come across material with a strong radial pattern being assigned to the genus. Last year a major Triassic exhibit opened in a major U. S. natural history museum. In this exhibit (which is for the most part very well done) Desmatosuchus is represented by an osteoderm, which has an extreme radial patterning, a posteriorly placed boss, and a raised anterior bar, the exact reverse of the diagnosis of Desmatosuchus.
When I was visiting museum collections on a very limited budget as a graduate student it was extremely frustrating to travel to institutions and then find out that all of the Desmatosuchus material was misidentified. It is even more frustrating to see this continuing, and yes it does have implications. Periodically you will see papers come out where comparisons with Desmatosuchus are being made, yet it quickly becomes apparent (at least to me) that the comparisons are based on a misidentified specimen. Desmatosuchus also possibly has some biostratigraphic significance, but again many voucher specimens for purported occurrences are based on misidentifications. Finally, a misidentification of material as Desmatosuchus eventually placed me in one of the most frustrating and unfortunate situations I have every found myself in in my entire life.
I do realize that misidentifications happen all the time with lots of fossils, however, it is unfortunate when it is done over and over again. Below are some representative plates and drawings of Desmatosuchus spurensis. The photographed material is MNA V9300. The drawings are from Long and Ballew (1985).
OK...rant over. Thanks for reading and please ID your Desmatosuchus material correctly.
REFERENCE
Long, R. A., and K. L. Ballew. 1985. Aetosaur dermal armor from the Late Triassic of southwestern North America, with special reference to material from the Chinle Formation of Petrified Forest National Park. Museum of Northern Arizona Bulletin 54:45-68.
Triassic Literature Recap - 2008
2008 was an excellent year for new and exciting infomation on the Triassic. Some highlights included two new (and somewhat conflicting) basal turtle discoveries, several new temnospondyls, a reexamination of "dinosaur superiority", ethical controversy, and finally several important dissertations. These dissertations as well as published abstracts promise that 2009 will be just as exciting.
This is not an entirely exhaustive list, but hopefully fairly complete. It does not include all geological papers or invertebrates. It was also cross-checked with Tracy Ford's dinohunter site.
By the way...the most prolific author for Triassic VP in 2008 is...... Mike Benton with five papers.
2008 Triassic Vertebrate Paleontology Literature
Brusatte, S.L., Benton, M.J., Ruta, M., and G.T. Lloyd. 2008. Superiority, competition, and opportunism in the evolutionary radiation of dinosaurs. Science 321:1485-1488.
Brusatte, S. L., Benton, M. J., Ruta, M., and G. T. Lloyd. 2008. The first 50 Myr of dinosaur evolution: macroevolutionary pattern and morphological disparity. Biology Letters, published online, 4pp.
Buffetaut, E., and M. Novak. 2008. A cyamodont placodont (Reptilia: Sauropterygia) from the Triassic of Solovenia. Palaeontology 51:1301-1306.
Butler, R. J., Upchurch, P., and D. B. Norman. 2008. The phylogeny of the ornithischian dinosaurs. Journal of Systematic Palaeontology 4:1-40.
Cisneros, J. C. 2008. Taxonomic status of the reptile genus Procolophon from the Gondwanana Triassic. Palaeontographic Africana 43:7-17.
Cisneros, J. C. 2008. Phylogenetic relationships of procolophonid parareptiles with remarks on thier geological record. Journal of Systematic Paleontology 6:345-366.
Cisneros, J. C. 2008. New basal procolophonid reptile from the Katberg formation (Lower Triassic) of the South African Karoo. Paleoworld 17:126-134.
Cleveland D. M., Nordt, L. C., and S. C. Atchley. 2008. Paleosols, trace fossils, and precipitation estimates of the uppermost Triassic strata in northern New Mexico. Palaeogeography, Palaeoclimatology, Palaeoecology 257:421-444.
Dalton, R. 2008. Fossil reptiles mired in controversy. Nature 451:510.
Damiani, R. 2008. A giant skull of the temnospondyl Xenotosuchus africanus from the Middle Triassic of South Aferica and its ontogenetic implications. Acta Palaeontologica Polonica 53:75-84.
Dias-da-Silva, S., Dias, E.V., and C.L. Schultz. 2009. First record of stereospondyls (Tetrapoda, Temnospondyli) in the Upper Triassic of Southern Brazil. Gondwana Research 15:131-136.
Diedrich, C. 2008. Millions of reptile tracks – Early to Middle Triassic carbonate tidal flat migration bridges of Central Europe – reptile immigration into the Germanic basin. Palaeogeography, Palaeoclimatology, Palaeoecology 259:410-423.
Dzik, J., Sulej, T., and G. Niedźwiedzki. 2008. A dicynodont−theropod association in the latest Triassic of Poland. Acta Palaeontologica Polonica 53:733–738.
Galton, P. M. 2008. Notes on the remains of archosaurian reptiles, mostly basal sauropodomorph dinosaurs, from the 1834 fissure fill (Rhaetian, Upper Triassic) at Clifton in Bristol, southwest England. Revue de Paleobiologie 26:505-591.
Heckert, A. B., Lucas, S. G., Rinehart, L. F., and A. P. Hunt. 2008. A new genus and species of sphenodontian from the Ghost Ranh Coelophysis Quarry (Upper Triassic: Apachean), Rock Point Formation, New Mexico, USA. Palaeontology 51:827-845.
Holmes, R., Cheng, Y.-N., and X.-C.Wu. 2008. New information on the skull of Keichuosaurus hui (Reptilia: Sauropterygia) with comments on sauropterygian interrelationships. Journal of Vertebrate Paleontology 28:76-84.
Hone, D. W. E., and M. J. Benton, M. J. 2008. A new genus of rhynchosaur from the Middle Triassic of South-West England. Palaeontology 51:95-115.
Irmis, R. B. 2008. Perspectives on the origin and early diversification of dinosaurs. PhD dissertation, Department of Integrative Biology, University of California, Berkeley, 421 pp.
Jenkins, F. A., Jr., Shubin, N. H., Gatesy, S. M., and A. 2008. Gerrothorax pulcherrimus from the Upper Triassic Fleming Fjord Formation of East Greenland and a reassessment of head lifting in temnospondyl feeding. Journal of Vertebrate Paleontology 28: 935–950.
Jiang, D.-Y., Motani, R., Hao, W.-C., Rieppel, O., Sun, Y.-L., Schmitz, L., and Z.-Y. Suny. 2008. First record of Placodontoidea (Reptilia, Sauropterygia, Placodontia) from the Eastern Tethys. Journal of Vertebrate Paleontology 28:904-908.
Jiang, D.-Y., Rieppel, O., Montani, R., Hao, W.-C., Sun, Y.-L., Schmitz, L., and Z.-Y. Sun. 2008. A new Middle Triassic Eosauropterygian (Reptilia, Sauropterygia) from Southwestern China. Journal of Vertebrate Paleontology 28:1055-1062.
Joyce, W. G., Lucas, S. G., Scheyer, T. M., Heckert, A. B., and A. P. Hunt. 2008. A thin-shelled reptile from the Late Triassic of North America and the origin of the turtle shell. Proceedings of the Royal Society B 276: 1656.
Kammerer, C. F., Flynn, J. J., Ranivoharimanana, L,. and A. R. Wyss. 2008. New material of Menadon besairiei (Cynodontia: Traversodontidae) from the Triassic of Madagascar. Journal of Vertebrate Paleontology 28:445-462.
Knoll, F. 2008. On the Procompsognathus postcranium (Late Triassic, Germany). Geobios 41:779-786.
Li, C., Wu, X.-C., Rieppel, O., Wang, L.-T., and L.-J. Zhao. 2008. An ancestral turtle from the Late Triassic of southwestern China. Nature 456:497-501.
Liu, J., Soares, M. B., and M. Reichel. 2008, Massetognathus (Cynodontia, Traversodontidae) from the Santa Maria Formation of Brazil. Revista Brasileira de Paleontologia 11:27-36.
Lucas, S. G., and L. H. Tanner. 2008. Reexamination of the end-Triassic mass extinction; pp. 66-103 in Elewa, A. M. T. (ed.), Mass Extinction. Springer-Verlag Publishers, Heidelberg, Germany.
Maisch, M. W., Jiang, D.-y., Hao, W.-c., Sun, Y.-l., Sun, Z.-y., and H. Stöhr. 2008. A well-preserved skull of Qianichthyosaurus zhoui Li, 1999, (Reptilia: Ichthyosauria) from the Upper Triassic of China and the phylogenetic position of the Toretocnemidae. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 248:257-266.
Mancuso, A. C., and C. A. Mariscano. 2008. Paleoenvironments and taphonomy of a Triassic lacustrine system (Los Rastros Formation, central-western Argentina). Palaios 23: 535-547.
Martz, J.W. 2008. Lithostratigraphy, chemostratigraphy, and vertebrate biostratigraphy of the Dockum Group (Upper Triassic), of southern Garza County, West Texas. Unpublished PhD dissertation. Texas Tech University, Lubbock, 504p.
Modesto, S. P., and J. Botha-Brink, J. 2008. Evidence of a second, large archosauriform reptile in the Lower Triassic Katberg Formation of South Africa. Journal of Vertebrate Paleontology 28:914-917.
Motani, R., Jiang, D.-Y., Tintori, A., Sun, Y.-L., Hao, W.-C., Boyd, A., Hinic-Frlog, S., Schmitz, L., Shin, J.-Y., and Z.-Y. Sun. 2008. Horizons and assemblages of Middle Triassic Marine reptiles from Panxian, Guizhou, China. Journal of Vertebrate Paleontology 28:900-903.
Nesbitt, S. J., and S. Chatterjee. 2008. Late Triassic dinosauriforms from the Post Quarry and surrounding areas, west Texas, USA. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 249:143-156.
Nesbitt, S.J., and M.R. Stocker. 2008. The vertebrate assemblage of the Late Triassic Canjilon Quarry (Northern New Mexico, USA) and the importance of apomorphy based assemblage comparisons. Journal of Vertebrate Paleontology 28:1063-1072.
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.
Parker, W. G., and B. J. Barton. 2008. New information on the Upper Triassic archosauriform Vancleavea campi based on new material from the Chinle Formation of Arizona. Palaeontologia Electronica 11.3.14a, 20pp.
Parker, W.G., Stocker, M.R., and R.B. Irmis. 2008. A new desmatosuchine aetosaur (Archosauria: Suchia) from the Upper Triassic Tecovas Formation (Dockum Group) of Texas. Journal of Vertebrate Paleontology 28:692-701.
Peyer, K., Carter, J. G., Sues, H.-D., Novak, S. E., and P. E. Olsen. 2008. A new suchian archosaur from the Upper Triassic of North Carolina. Journal of Vertebrate Paleontology 28:363-381.
Renesto, S. 2008. Remains of a juvenile phytosaur from the Late Triassic of northern Italy. Rivista Italiana di Paleontologia e Stratigrafia 114:155-160.
Richter, M., and C. E. V. Toledo. 2008. The first Triassic lungfish from South America (Santa Maria Formation, Parana Basin) and its bearing on geological correlations within Pangaea, pp. 43-54 in Cavin, L., Longbottom, A., and M. Richter, M. (eds.) Fishes and the Break-up of Pangaea. The Geological Society Special Publication 295.
de Ricqles, A., Padian, K., Knoll, F., and J. R. Horner. 2008. On the origin of high growth rates in archosaurs and thier ancient relatives: complementary histological studies on Triassic archosauriforms and the problem of a "phylogenetic signial" in bone histology. Annales de Paleontologie 94:57-76.
Rieppel, O., Li, C., and N. C. Fraser. 2008. The skeletal anatomy of the Triassic protosaur Dinocephalosaurus orientalis Li from the Middle Triassic of Guizhou Province, Southern China. Journal of Vertebrate Paleontology 28: 95-110.
Ruta, M., and J. R. Bolt. 2008. The brachyopoid Hadrokkosaurus bradyi from the early Middle Triassic of Arizona, and a phylogenetic analysis of lower jaw characters in temnospondyl amphibians. Acta Palaeontologica Polonica 53:579-592.
Säilä, L. K. 2008. The osteology and affinities of Anomoiodon liliensterni, a procolophonid reptile from the Lower Triassic Bundsandstein of Germany. Journal of Vertebrate Paleontology 28:1199-1205.
Scheyer, T. M. 2008. Aging the oldest turtles: the placodont affinities of Priscochelys hegnabrunnensis. Naturwissenschaften 95:803-810.
Schoch, R. R. 2008. A new stereospondyl from the German Middle Triassic, and the origin of the Metoposauridae. Zoological Journal of the Linnean Society 152:79-113.
Sidor, C., Miller, M., and J. Isbell. 2008. Tetrapod burrows from the Triassic of Antarctica: Journal of Vertebrate Paleontology 28: 277-284.
Sidor, C. A., Damiani, R., and W. R. Hammer. 2008. A new temnospondyl from Antarctica and a review of Fremouv Formation biostratigraphy. Journal of Vertebrate Paleontology 28:656-663.
Spielmann, J. A., Lucas, S. G., Rinehart, L. F., and A. B. Heckert. 2008. The Late Triassic Archosauromorph Trilophosaurus. New Mexico Museum of Natural History and Science Bulletin 43:1-177.
Stein, K., Palmer, C., Gill, P. G., and M. J. Benton. 2008. The aerodynamics of the British Late Triassic Kuehneosauridae. Palaeontology 51:967-981.
Stocker, M. R. 2008. The relationships of the phytosaur Leptosuchus Case 1922 with descriptions of new material from Petrified Forest National Park, Arizona. Unpublished M.S. Thesis, University of Iowa, Iowa City, 220p.
Sues, H.-D., and R. R. Reisz. 2008. Anatomy and phylogenetic relationships of Sclerosaurus armatus (Amniota: Parareptilia) from the Buntsandstein (Triassic) of Europe. Journal of Vertebrate Paleontology 28:1031-1042.
Surkov, M. V., and M. J. Benton. 2008, Head kinematics and feeding adaptations of the Permian and Triassic dicynodonts. Journal of Vertebrate Paleontology 28:1120-1129.
Valais, S. de, and R. N. Melchor. 2008. Ichnotaxonomy of bird-like footprints: an example from the Late Triassic-Early Jurassic of northwest Argentina. Journal of Vertebrate Paleontology 28:145-159.
Voight, S., Buchwitz, M., Fischer, J., Krause, D., and R. Georgi. 2008. Feather-like development of Triassic diapsid skin appendages. Naturwissenschaften
Wang, X., Bachmann, G. R., Hagdorn, H., Sanders, P. M., Cuny, G., Chen, X., Wang, C., Chen, L., Chen, L., Meng, F., and G. Xu, G. 2008. The Late Triassic Black Shales of Guanling area, Guizhou Province, South-West China: a unique marine reptile and pelagic crinoid fossil lagerstatte. Palaeontology 51:27-61.
Weinbaum, J. C. 2008. Review of the Triassic reptiles Poposaurus gracilis and Postosuchus kirkpatricki (Reptilia: Archosauria). Unpublished PhD dissertation, Texas Tech University, 183.
Whitside, D. I., and J. E. A. Marshall. 2008. The age, fauna and palaeoenvironment of the Late Triassic fisure deposits of Tytherington, South Gloucestershire, UK. Geological Magazine 141:105-147.
Witzmann, F., and T. Gassner. 2008. Metoposaurid and mastodonsaurid stereospondyls from the Triassic-Jurassic boundary of Portugal. Alcheringa 32:37-51.
Witzmann, F., Schoch, R. R., and M. W. Maisch. 2008. A relict basal tetrapod from Germany: first evidence of a Triassic chroniosuchian outside Russia: Naturwissenschaften 95:67-72.
Witzmann, F. and R. Soler-Gijón. 2008. The bone histology of osteoderms in temnospondyl amphibians and in the chroniosuchian Bystrowiella. Acta Zoologica. Early Online. DOI: 10.1111/j.1463-6395.2008.00385.x.
Zeigler, K.E. 2008. Stratigraphy, paleomagnetism, and magnetostratigraphy of the Upper Triassic Chinle Group, North-central New Mexico and preliminary magnetostratigraphy of the Lower Cretaceous Cedar Mountain Formation, Eastern Utah. Unpublished PhD dissertation, University of New Mexico, 224p.
Zeigler, K. E., Kelley, S., and J. W. Geissmann. 2008. Revisions to stratigraphic nomenclature of the Upper Triassic Chinle Group in New Mexico: New insights from geologic mapping, sedimentology, and magnetostratigraphic/paleomagnetic data. Rocky Mountain Geology 43:121-141.
Zhao, L., Sato, T., and C. Li. 2008. The most complete pistosauroid skeleton from the Triassic of Yunnan, China. Vertebrata PalAsiatica 82:283-286.
This is not an entirely exhaustive list, but hopefully fairly complete. It does not include all geological papers or invertebrates. It was also cross-checked with Tracy Ford's dinohunter site.
By the way...the most prolific author for Triassic VP in 2008 is...... Mike Benton with five papers.
2008 Triassic Vertebrate Paleontology Literature
Brusatte, S.L., Benton, M.J., Ruta, M., and G.T. Lloyd. 2008. Superiority, competition, and opportunism in the evolutionary radiation of dinosaurs. Science 321:1485-1488.
Brusatte, S. L., Benton, M. J., Ruta, M., and G. T. Lloyd. 2008. The first 50 Myr of dinosaur evolution: macroevolutionary pattern and morphological disparity. Biology Letters, published online, 4pp.
Buffetaut, E., and M. Novak. 2008. A cyamodont placodont (Reptilia: Sauropterygia) from the Triassic of Solovenia. Palaeontology 51:1301-1306.
Butler, R. J., Upchurch, P., and D. B. Norman. 2008. The phylogeny of the ornithischian dinosaurs. Journal of Systematic Palaeontology 4:1-40.
Cisneros, J. C. 2008. Taxonomic status of the reptile genus Procolophon from the Gondwanana Triassic. Palaeontographic Africana 43:7-17.
Cisneros, J. C. 2008. Phylogenetic relationships of procolophonid parareptiles with remarks on thier geological record. Journal of Systematic Paleontology 6:345-366.
Cisneros, J. C. 2008. New basal procolophonid reptile from the Katberg formation (Lower Triassic) of the South African Karoo. Paleoworld 17:126-134.
Cleveland D. M., Nordt, L. C., and S. C. Atchley. 2008. Paleosols, trace fossils, and precipitation estimates of the uppermost Triassic strata in northern New Mexico. Palaeogeography, Palaeoclimatology, Palaeoecology 257:421-444.
Dalton, R. 2008. Fossil reptiles mired in controversy. Nature 451:510.
Damiani, R. 2008. A giant skull of the temnospondyl Xenotosuchus africanus from the Middle Triassic of South Aferica and its ontogenetic implications. Acta Palaeontologica Polonica 53:75-84.
Dias-da-Silva, S., Dias, E.V., and C.L. Schultz. 2009. First record of stereospondyls (Tetrapoda, Temnospondyli) in the Upper Triassic of Southern Brazil. Gondwana Research 15:131-136.
Diedrich, C. 2008. Millions of reptile tracks – Early to Middle Triassic carbonate tidal flat migration bridges of Central Europe – reptile immigration into the Germanic basin. Palaeogeography, Palaeoclimatology, Palaeoecology 259:410-423.
Dzik, J., Sulej, T., and G. Niedźwiedzki. 2008. A dicynodont−theropod association in the latest Triassic of Poland. Acta Palaeontologica Polonica 53:733–738.
Galton, P. M. 2008. Notes on the remains of archosaurian reptiles, mostly basal sauropodomorph dinosaurs, from the 1834 fissure fill (Rhaetian, Upper Triassic) at Clifton in Bristol, southwest England. Revue de Paleobiologie 26:505-591.
Heckert, A. B., Lucas, S. G., Rinehart, L. F., and A. P. Hunt. 2008. A new genus and species of sphenodontian from the Ghost Ranh Coelophysis Quarry (Upper Triassic: Apachean), Rock Point Formation, New Mexico, USA. Palaeontology 51:827-845.
Holmes, R., Cheng, Y.-N., and X.-C.Wu. 2008. New information on the skull of Keichuosaurus hui (Reptilia: Sauropterygia) with comments on sauropterygian interrelationships. Journal of Vertebrate Paleontology 28:76-84.
Hone, D. W. E., and M. J. Benton, M. J. 2008. A new genus of rhynchosaur from the Middle Triassic of South-West England. Palaeontology 51:95-115.
Irmis, R. B. 2008. Perspectives on the origin and early diversification of dinosaurs. PhD dissertation, Department of Integrative Biology, University of California, Berkeley, 421 pp.
Jenkins, F. A., Jr., Shubin, N. H., Gatesy, S. M., and A. 2008. Gerrothorax pulcherrimus from the Upper Triassic Fleming Fjord Formation of East Greenland and a reassessment of head lifting in temnospondyl feeding. Journal of Vertebrate Paleontology 28: 935–950.
Jiang, D.-Y., Motani, R., Hao, W.-C., Rieppel, O., Sun, Y.-L., Schmitz, L., and Z.-Y. Suny. 2008. First record of Placodontoidea (Reptilia, Sauropterygia, Placodontia) from the Eastern Tethys. Journal of Vertebrate Paleontology 28:904-908.
Jiang, D.-Y., Rieppel, O., Montani, R., Hao, W.-C., Sun, Y.-L., Schmitz, L., and Z.-Y. Sun. 2008. A new Middle Triassic Eosauropterygian (Reptilia, Sauropterygia) from Southwestern China. Journal of Vertebrate Paleontology 28:1055-1062.
Joyce, W. G., Lucas, S. G., Scheyer, T. M., Heckert, A. B., and A. P. Hunt. 2008. A thin-shelled reptile from the Late Triassic of North America and the origin of the turtle shell. Proceedings of the Royal Society B 276: 1656.
Kammerer, C. F., Flynn, J. J., Ranivoharimanana, L,. and A. R. Wyss. 2008. New material of Menadon besairiei (Cynodontia: Traversodontidae) from the Triassic of Madagascar. Journal of Vertebrate Paleontology 28:445-462.
Knoll, F. 2008. On the Procompsognathus postcranium (Late Triassic, Germany). Geobios 41:779-786.
Li, C., Wu, X.-C., Rieppel, O., Wang, L.-T., and L.-J. Zhao. 2008. An ancestral turtle from the Late Triassic of southwestern China. Nature 456:497-501.
Liu, J., Soares, M. B., and M. Reichel. 2008, Massetognathus (Cynodontia, Traversodontidae) from the Santa Maria Formation of Brazil. Revista Brasileira de Paleontologia 11:27-36.
Lucas, S. G., and L. H. Tanner. 2008. Reexamination of the end-Triassic mass extinction; pp. 66-103 in Elewa, A. M. T. (ed.), Mass Extinction. Springer-Verlag Publishers, Heidelberg, Germany.
Maisch, M. W., Jiang, D.-y., Hao, W.-c., Sun, Y.-l., Sun, Z.-y., and H. Stöhr. 2008. A well-preserved skull of Qianichthyosaurus zhoui Li, 1999, (Reptilia: Ichthyosauria) from the Upper Triassic of China and the phylogenetic position of the Toretocnemidae. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 248:257-266.
Mancuso, A. C., and C. A. Mariscano. 2008. Paleoenvironments and taphonomy of a Triassic lacustrine system (Los Rastros Formation, central-western Argentina). Palaios 23: 535-547.
Martz, J.W. 2008. Lithostratigraphy, chemostratigraphy, and vertebrate biostratigraphy of the Dockum Group (Upper Triassic), of southern Garza County, West Texas. Unpublished PhD dissertation. Texas Tech University, Lubbock, 504p.
Modesto, S. P., and J. Botha-Brink, J. 2008. Evidence of a second, large archosauriform reptile in the Lower Triassic Katberg Formation of South Africa. Journal of Vertebrate Paleontology 28:914-917.
Motani, R., Jiang, D.-Y., Tintori, A., Sun, Y.-L., Hao, W.-C., Boyd, A., Hinic-Frlog, S., Schmitz, L., Shin, J.-Y., and Z.-Y. Sun. 2008. Horizons and assemblages of Middle Triassic Marine reptiles from Panxian, Guizhou, China. Journal of Vertebrate Paleontology 28:900-903.
Nesbitt, S. J., and S. Chatterjee. 2008. Late Triassic dinosauriforms from the Post Quarry and surrounding areas, west Texas, USA. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen 249:143-156.
Nesbitt, S.J., and M.R. Stocker. 2008. The vertebrate assemblage of the Late Triassic Canjilon Quarry (Northern New Mexico, USA) and the importance of apomorphy based assemblage comparisons. Journal of Vertebrate Paleontology 28:1063-1072.
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.
Parker, W. G., and B. J. Barton. 2008. New information on the Upper Triassic archosauriform Vancleavea campi based on new material from the Chinle Formation of Arizona. Palaeontologia Electronica 11.3.14a, 20pp.
Parker, W.G., Stocker, M.R., and R.B. Irmis. 2008. A new desmatosuchine aetosaur (Archosauria: Suchia) from the Upper Triassic Tecovas Formation (Dockum Group) of Texas. Journal of Vertebrate Paleontology 28:692-701.
Peyer, K., Carter, J. G., Sues, H.-D., Novak, S. E., and P. E. Olsen. 2008. A new suchian archosaur from the Upper Triassic of North Carolina. Journal of Vertebrate Paleontology 28:363-381.
Renesto, S. 2008. Remains of a juvenile phytosaur from the Late Triassic of northern Italy. Rivista Italiana di Paleontologia e Stratigrafia 114:155-160.
Richter, M., and C. E. V. Toledo. 2008. The first Triassic lungfish from South America (Santa Maria Formation, Parana Basin) and its bearing on geological correlations within Pangaea, pp. 43-54 in Cavin, L., Longbottom, A., and M. Richter, M. (eds.) Fishes and the Break-up of Pangaea. The Geological Society Special Publication 295.
de Ricqles, A., Padian, K., Knoll, F., and J. R. Horner. 2008. On the origin of high growth rates in archosaurs and thier ancient relatives: complementary histological studies on Triassic archosauriforms and the problem of a "phylogenetic signial" in bone histology. Annales de Paleontologie 94:57-76.
Rieppel, O., Li, C., and N. C. Fraser. 2008. The skeletal anatomy of the Triassic protosaur Dinocephalosaurus orientalis Li from the Middle Triassic of Guizhou Province, Southern China. Journal of Vertebrate Paleontology 28: 95-110.
Ruta, M., and J. R. Bolt. 2008. The brachyopoid Hadrokkosaurus bradyi from the early Middle Triassic of Arizona, and a phylogenetic analysis of lower jaw characters in temnospondyl amphibians. Acta Palaeontologica Polonica 53:579-592.
Säilä, L. K. 2008. The osteology and affinities of Anomoiodon liliensterni, a procolophonid reptile from the Lower Triassic Bundsandstein of Germany. Journal of Vertebrate Paleontology 28:1199-1205.
Scheyer, T. M. 2008. Aging the oldest turtles: the placodont affinities of Priscochelys hegnabrunnensis. Naturwissenschaften 95:803-810.
Schoch, R. R. 2008. A new stereospondyl from the German Middle Triassic, and the origin of the Metoposauridae. Zoological Journal of the Linnean Society 152:79-113.
Sidor, C., Miller, M., and J. Isbell. 2008. Tetrapod burrows from the Triassic of Antarctica: Journal of Vertebrate Paleontology 28: 277-284.
Sidor, C. A., Damiani, R., and W. R. Hammer. 2008. A new temnospondyl from Antarctica and a review of Fremouv Formation biostratigraphy. Journal of Vertebrate Paleontology 28:656-663.
Spielmann, J. A., Lucas, S. G., Rinehart, L. F., and A. B. Heckert. 2008. The Late Triassic Archosauromorph Trilophosaurus. New Mexico Museum of Natural History and Science Bulletin 43:1-177.
Stein, K., Palmer, C., Gill, P. G., and M. J. Benton. 2008. The aerodynamics of the British Late Triassic Kuehneosauridae. Palaeontology 51:967-981.
Stocker, M. R. 2008. The relationships of the phytosaur Leptosuchus Case 1922 with descriptions of new material from Petrified Forest National Park, Arizona. Unpublished M.S. Thesis, University of Iowa, Iowa City, 220p.
Sues, H.-D., and R. R. Reisz. 2008. Anatomy and phylogenetic relationships of Sclerosaurus armatus (Amniota: Parareptilia) from the Buntsandstein (Triassic) of Europe. Journal of Vertebrate Paleontology 28:1031-1042.
Surkov, M. V., and M. J. Benton. 2008, Head kinematics and feeding adaptations of the Permian and Triassic dicynodonts. Journal of Vertebrate Paleontology 28:1120-1129.
Valais, S. de, and R. N. Melchor. 2008. Ichnotaxonomy of bird-like footprints: an example from the Late Triassic-Early Jurassic of northwest Argentina. Journal of Vertebrate Paleontology 28:145-159.
Voight, S., Buchwitz, M., Fischer, J., Krause, D., and R. Georgi. 2008. Feather-like development of Triassic diapsid skin appendages. Naturwissenschaften
Wang, X., Bachmann, G. R., Hagdorn, H., Sanders, P. M., Cuny, G., Chen, X., Wang, C., Chen, L., Chen, L., Meng, F., and G. Xu, G. 2008. The Late Triassic Black Shales of Guanling area, Guizhou Province, South-West China: a unique marine reptile and pelagic crinoid fossil lagerstatte. Palaeontology 51:27-61.
Weinbaum, J. C. 2008. Review of the Triassic reptiles Poposaurus gracilis and Postosuchus kirkpatricki (Reptilia: Archosauria). Unpublished PhD dissertation, Texas Tech University, 183.
Whitside, D. I., and J. E. A. Marshall. 2008. The age, fauna and palaeoenvironment of the Late Triassic fisure deposits of Tytherington, South Gloucestershire, UK. Geological Magazine 141:105-147.
Witzmann, F., and T. Gassner. 2008. Metoposaurid and mastodonsaurid stereospondyls from the Triassic-Jurassic boundary of Portugal. Alcheringa 32:37-51.
Witzmann, F., Schoch, R. R., and M. W. Maisch. 2008. A relict basal tetrapod from Germany: first evidence of a Triassic chroniosuchian outside Russia: Naturwissenschaften 95:67-72.
Witzmann, F. and R. Soler-Gijón. 2008. The bone histology of osteoderms in temnospondyl amphibians and in the chroniosuchian Bystrowiella. Acta Zoologica. Early Online. DOI: 10.1111/j.1463-6395.2008.00385.x.
Zeigler, K.E. 2008. Stratigraphy, paleomagnetism, and magnetostratigraphy of the Upper Triassic Chinle Group, North-central New Mexico and preliminary magnetostratigraphy of the Lower Cretaceous Cedar Mountain Formation, Eastern Utah. Unpublished PhD dissertation, University of New Mexico, 224p.
Zeigler, K. E., Kelley, S., and J. W. Geissmann. 2008. Revisions to stratigraphic nomenclature of the Upper Triassic Chinle Group in New Mexico: New insights from geologic mapping, sedimentology, and magnetostratigraphic/paleomagnetic data. Rocky Mountain Geology 43:121-141.
Zhao, L., Sato, T., and C. Li. 2008. The most complete pistosauroid skeleton from the Triassic of Yunnan, China. Vertebrata PalAsiatica 82:283-286.
Was Postosuchus bipedal or quadrupedal?
My post presenting a new reconstruction of Postosuchus kirkpatricki generated some discussion on whether or not Postosuchus was an obligate biped or quadrupedal. Jeff Martz’s reconstruction (below and revised from the earlier post) is based on research by Jonathan Weinbaum arguing the former (Weinbaum, 2008). In his dissertation Jonathan provides several lines of evidence which he feels clearly demonstrates that Postosuchus is bipedal. This includes a shortened forelimb with an extremely reduced manus, elongate and narrow pubes and ischia (a condition which he claims is only found in bipeds), and the presence of hyposphenes and hypantra in the dorsal vertebrae (which restrict lateral movement and were at one time believed to only occur in dinosaurs, although I showed in 2008 that they also occur in quadrupedal aetosaurians). Some more compelling evidence presented by Weinbaum (2008) is the structure of the brain endocast which is very similar to that of bipedal dinosaurs. He also used a vertebral analysis tool developed by Christian and Preuschoft (1996), which demonstrates that vertebrae are enlarged in areas of support. Quadrupeds show two enlargement areas, whereas bipeds show only one. Postosuchus shows only a single peak above the pelvis, typical for bipeds. 
Jonathan is not the first to suggest this. Sankar Chatterjee, in his initial description of Postosuchus (Chatterjee, 1985), also suggested that it was bipedal based on a short trunk and forelimbs. He also showed that the forelimb/hindlimb ratio in Postosuchus was similar to the theropod Ornitholestes; however, according to the published dataset (which only includes a few taxa), the ratio is much higher than in other theropods such as Coelophysis, Allosaurus, and Albertosaurus, which are bipedal as are all theropods.
Weinbaum (2008) also looked at forelimb/hindlimb length ratios, and provided a ratio of .59 for Postosuchus, which he claimed falls between that Gallimimus and Deinonychus. Despite Weinbaum’s (2008) claims, I feel that the forelimb is not really that much shorter than the hindlimb (i.e. .59), and thus not conclusive evidence. Again, however, this was a very limited dataset. I would like to see comparisons with more taxa from a variety of archosauromorph clades as both Chatterjee (1985) and Weinbaum (2008) found that Postosuchus has a similar ratio to some of the longest limbed coelurosaurs rather than all theropods in general. I do not find this compelling.
All other workers (e.g., Long and Murry, 1995) have suggested that Postosuchus is quadrupedal (see reconstruction from Wikipedia below), which is how all other non-poposaurid “rauisuchians” have been portrayed. This is mainly based on track evidence, where the ichnotaxon Cheirotherium has been ascribed to a “rauisuchian” trackmaker. Cheirotherium tracks were made by a quadrupedal non-ornthodiran archosaur with a highly reduced manus. Furthermore, Peyer et al. (2008) argued that although the manus is extremely reduced, the pectoral girdle of Postosuchus is robust suggesting that it was used in locomotion.
However, there is trackway evidence that possibly supports bipedal Postosuchus. Olsen and Huber (1998) described tracks in the Upper Triassic Pekin Formation (which includes Postosuchus) as matching well with the pes of Postosuchus and having no sign of a manus impression.
Was Postosuchus capable of bipedal movement? Based on limb ratios and other lines of evidence, yes. Was it an obligate biped? Unfortunately we cannot say for certain as the available data is ambiguous. What is needed is a similar study as that conducted by Bonnan and Senter (2007) for “prosauropods”. These authors argued that as quadrupedal animals must pronate the forelimb for it to provide propulsion, evidence for this must be found to support this type locomotion (or the opposite to support bipedalism). Until a similar study is conducted for Postosuchus, I would say that the case is far from closed.
REFERENCES
Bonnan, M. F., and P. Senter. 2007. Were the basal sauropodomorph dinosaurs Plateosaurus and Massospondylus habitual quadrupeds? Special Papers in Palaeontology 77:139-155.
Chatterjee, S. 1985. Postosuchus, a new thecodontian reptile from the Triassic of Texas
and the origin of tyrannosaurs. Philosophical Transactions of the Royal Society of London, Series B 309, 395-460; London.
Christian, A., and H. Preuschoft. 1996. Deducing the body posture of extinct large vertebrates from the shape of the vertebral column. Palaeontology 39:801-812.
Long, R. A., and P. A. Murry. 1995. Late Triassic (Carnian and Norian) tetrapods from the southwestern United States. New Mexico Museum of Natural History and Science, Bulletin 4:1–254.
Olsen, P. E. and Huber, P., 1998, The oldest Late Triassic footprint assemblage from North America (Pekin Formation, Deep River basin, North Carolina, USA). Southestern Geology, v. 38, no. 2, p. 77-90.
Peyer, K., Carter, J. G., Sues, H.-D., Novak, S. E., and P. E. Olsen. 2008. A new suchian archosaur from the Upper Triassic of North Carolina. Journal of Vertebrate Paleontology 28:363-381.
Weinbaum, J. C. 2008. Review of the Triassic reptiles Poposaurus gracilis and Postosuchus kirkpatricki (Reptilia: Archosauria). Unpublished PhD dissertation, Texas Tech University, 183.
Jonathan is not the first to suggest this. Sankar Chatterjee, in his initial description of Postosuchus (Chatterjee, 1985), also suggested that it was bipedal based on a short trunk and forelimbs. He also showed that the forelimb/hindlimb ratio in Postosuchus was similar to the theropod Ornitholestes; however, according to the published dataset (which only includes a few taxa), the ratio is much higher than in other theropods such as Coelophysis, Allosaurus, and Albertosaurus, which are bipedal as are all theropods.Weinbaum (2008) also looked at forelimb/hindlimb length ratios, and provided a ratio of .59 for Postosuchus, which he claimed falls between that Gallimimus and Deinonychus. Despite Weinbaum’s (2008) claims, I feel that the forelimb is not really that much shorter than the hindlimb (i.e. .59), and thus not conclusive evidence. Again, however, this was a very limited dataset. I would like to see comparisons with more taxa from a variety of archosauromorph clades as both Chatterjee (1985) and Weinbaum (2008) found that Postosuchus has a similar ratio to some of the longest limbed coelurosaurs rather than all theropods in general. I do not find this compelling.
All other workers (e.g., Long and Murry, 1995) have suggested that Postosuchus is quadrupedal (see reconstruction from Wikipedia below), which is how all other non-poposaurid “rauisuchians” have been portrayed. This is mainly based on track evidence, where the ichnotaxon Cheirotherium has been ascribed to a “rauisuchian” trackmaker. Cheirotherium tracks were made by a quadrupedal non-ornthodiran archosaur with a highly reduced manus. Furthermore, Peyer et al. (2008) argued that although the manus is extremely reduced, the pectoral girdle of Postosuchus is robust suggesting that it was used in locomotion.
However, there is trackway evidence that possibly supports bipedal Postosuchus. Olsen and Huber (1998) described tracks in the Upper Triassic Pekin Formation (which includes Postosuchus) as matching well with the pes of Postosuchus and having no sign of a manus impression.
Was Postosuchus capable of bipedal movement? Based on limb ratios and other lines of evidence, yes. Was it an obligate biped? Unfortunately we cannot say for certain as the available data is ambiguous. What is needed is a similar study as that conducted by Bonnan and Senter (2007) for “prosauropods”. These authors argued that as quadrupedal animals must pronate the forelimb for it to provide propulsion, evidence for this must be found to support this type locomotion (or the opposite to support bipedalism). Until a similar study is conducted for Postosuchus, I would say that the case is far from closed.
REFERENCES
Bonnan, M. F., and P. Senter. 2007. Were the basal sauropodomorph dinosaurs Plateosaurus and Massospondylus habitual quadrupeds? Special Papers in Palaeontology 77:139-155.
Chatterjee, S. 1985. Postosuchus, a new thecodontian reptile from the Triassic of Texas
and the origin of tyrannosaurs. Philosophical Transactions of the Royal Society of London, Series B 309, 395-460; London.
Christian, A., and H. Preuschoft. 1996. Deducing the body posture of extinct large vertebrates from the shape of the vertebral column. Palaeontology 39:801-812.
Long, R. A., and P. A. Murry. 1995. Late Triassic (Carnian and Norian) tetrapods from the southwestern United States. New Mexico Museum of Natural History and Science, Bulletin 4:1–254.
Olsen, P. E. and Huber, P., 1998, The oldest Late Triassic footprint assemblage from North America (Pekin Formation, Deep River basin, North Carolina, USA). Southestern Geology, v. 38, no. 2, p. 77-90.
Peyer, K., Carter, J. G., Sues, H.-D., Novak, S. E., and P. E. Olsen. 2008. A new suchian archosaur from the Upper Triassic of North Carolina. Journal of Vertebrate Paleontology 28:363-381.
Weinbaum, J. C. 2008. Review of the Triassic reptiles Poposaurus gracilis and Postosuchus kirkpatricki (Reptilia: Archosauria). Unpublished PhD dissertation, Texas Tech University, 183.
100 Best Blogs for Earth Science Scholars
Well, Chinleana made a list of 100 best blogs for Earth Science Scholars, as did many of my colleagues on my blogroll. I'm honored to be included in this company and glad that people are enjoying my ramblings.
Anyhow, check it out as there is a great list of informative earth science blogs listed here [dead link 3/25/2013].
Anyhow, check it out as there is a great list of informative earth science blogs listed here [dead link 3/25/2013].
More on Postosuchus kirkpatricki
Postosuchus kirkpatricki was named by Chatterjee (1985) for rauisuchian material from the Post Quarry in the Upper Triassic Dockum Group of
About 10 years ago Jonathan Weinbaum started repreparing the type material (especially the skull) of Postosuchus, discovering a nearly complete skull under layers of paint, chicken wire, and plaster. His resulting MS thesis (Weinbaum, 2002) and PhD Dissertation (Weinbaum. 2008) provide the most up-to-date and accurate reconstruction of Postosuchus kirkpatricki. In 2008 Peyer et al. described a partial skeleton of a new species, Postosuchus alisonae, from the Upper Triassic of North Carolina. The reconstruction provided by Jeff Martz is based on these works.
Two side notes regarding the taxonomy of Postosuchus. The pelvis described by Case (1943) was found and donated to the University of Michigan Museum of Paleontology by a
Finally, Chatterjee (1985) named Postosuchus kirkpatricki for Mr. and Mrs. Kirkpatrick, therefore by ICZN conventions the specific name should actually be P. kirkpatrickorum. Since 1985 nobody has provided an emendation and the current volume of the code is ambiguous about whether an emendation should be made (as just recently discussed on the Dinosaur Mailing List).
The next post will discuss the bipedal/quadrupedal controversy...
The photo is the
REFERENCES
Case, E. C. 1943. A new form of phytosaur pelvis. American Journal of
Chatterjee, S. 1985. Postosuchus, a new thecodontian reptile from the Triassic of Texas and the origin of tyrannosaurs. Philosophical Transactions of the Royal Society of
Long, R. A., and P. A. Murry. 1995. Late Triassic (Carnian and Norian)
Murry, P. A., and R. A. Long. 1989. Geology and paleontology of the Chinle Formation, Petrified Forest National Park and vicinity, Arizona and a discussion of vertebrate fossils of the southwestern Upper Triassic; pp. 29-64 in Lucas, S. G., and A. P. Hunt (eds.), Dawn of the Dinosaurs in the American Southwest, University of New Mexico Press, Albuquerque.
Peyer, K., Carter, J. G., Sues, H.-D., Novak, S. E., and P. E. Olsen. 2008. A new suchian archosaur from the Upper Triassic of North Carolina. Journal of Vertebrate Paleontology 28:363-381.
Weinbaum, J. C. 2002. Osteology and relationships of Postosuchus kirkpatricki (Archosauria: Crurotarsi). Unpublished MS thesis,
Weinbaum, J. C. 2008. Review of the Triassic reptiles Poposaurus gracilis and Postosuchus kirkpatricki (Reptilia: Archosauria). Unpublished PhD dissertation,
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.
Congratulations Randy
At this time I would like to congratulate my good friend and colleague Randy Irmis, who just finished his dissertation (Irmis, 2008) at UC Berkeley and is moving to Utah to start his new job as an assistant professor in the Department of Geology and Geophysics at the University of Utah and curator of the Utah Museum of Natural History. Best of luck Randy!
This picture is from his University of Utah faculty webpage.
REFERENCE
Irmis, R.B. 2008. Perspectives on the origin and early diversification of dinosaurs. PhD dissertation, Department of Integrative Biology, University of California, Berkeley, 421 pp.
This picture is from his University of Utah faculty webpage.
REFERENCE
Irmis, R.B. 2008. Perspectives on the origin and early diversification of dinosaurs. PhD dissertation, Department of Integrative Biology, University of California, Berkeley, 421 pp.
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