This is an absolutely incredible find and akin to the fully articulated Poposaurus gracilis skeleton found in Utah by a Yale Peabody Museum field crew in 2003. I was fortunate enough to be present in 2003 to help with the initial uncovering and will never forget it. Articulated pseudosuchian finds like this are pretty rare in the Triassic.
The announcement is here:
http://forgottenarchosaurs.blogspot.com/2010/05/nearly-complete-prestosuchus-found.html
The original article is here:
http://br.noticias.yahoo.com/s/11052010/25/manchetes-fossil-megapredador-pre-historico-encontrado.html
....and what is sure to drive all fossil preparators who see this crazy, notice that the underside of the specimen is already jacketed and it appears to be undergoing prep in the field! Maybe the jacket was just moved to an outcrop for the photo op.
Revision of the Basal Sauropodomorph Anchisaurus polyzelus
This is the latest paper in the ongoing debate regarding the taxonomic validity of Anchisaurus polyzelus (Sauropodomorpha: Anchisauria) and the referral of three other partial specimens from the Early Jurassic Portland Formation of Massachusetts and Connecticut. Whereas, all workers now agree that the four specimens all belong to the same species, the debate has centered around the status of the type materials of A. polyzelus, because if they are not diagnostic, the next available name for this material is Ammosaurus major. Through reanalysis of the material Yates proposes seven autapomorphies diagnosing this material, including one of these also found in the holotype specimen of A. polyzelus. Thus, Yates argues that A. polyzelus is valid, all four specimens can unambiguously be referred to it, and that Ammosaurus major is the junior synonym. This paper also features a revised phylogentic analysis of the sauropodomorpha based on the reanalysis including repreparation of the skull found in one of the referred specimens. Anchisaurus is recovered at the base of Anchisauria and outside of Sauropoda.
As this is about the 6th paper in a little more than a decade dealing with this, I am awaiting the next installment ;).
Yates, A. M. in press. A revision of the problematic sauropodomorph dinosaurs from Manchester, Connecticut and the status of Anchisaurus Marsh. Palaeontology. doi: 10.1111/j.1475-4983.2010.00952.x
Abstract: The taxonomic status of the sauropodomorph dinosaurs from the Newark Supergroup of north-eastern USA is reviewed. The inclusion of the three articulated skeletons from Wolcott’s Quarry, Manchester, Connecticut in a single species is supported. Despite claims to the contrary the Manchester skeletons can be referred to the species Anchisaurus polyzelus, which is based on a fragmentary specimen from Massachusetts. Two autapomorphies: dorsoventrally flattened ischial blades set at a low angle to each other and slender sacral ribs of the first sacral vertebra, link the holotype of A. polyzelus to the Manchester specimens. A revised diagnosis of the species and new skull reconstruction are presented. Recent anatomical observations of A. polyzelus indicate that several character states used to assess its phylogenetic position require revision. However, these are not sufficient to overturn previous cladistic analyses. A revised cladistic analysis continues to find support for Anchisaurus as a relatively derived basal sauropodomorph that lies outside of the clade Melanorosaurus + Sauropoda but is more closely related to it than to ‘core prosauropods’ such as Plateosaurus and Massospondylus.
As this is about the 6th paper in a little more than a decade dealing with this, I am awaiting the next installment ;).
Yates, A. M. in press. A revision of the problematic sauropodomorph dinosaurs from Manchester, Connecticut and the status of Anchisaurus Marsh. Palaeontology. doi: 10.1111/j.1475-4983.2010.00952.x
Abstract: The taxonomic status of the sauropodomorph dinosaurs from the Newark Supergroup of north-eastern USA is reviewed. The inclusion of the three articulated skeletons from Wolcott’s Quarry, Manchester, Connecticut in a single species is supported. Despite claims to the contrary the Manchester skeletons can be referred to the species Anchisaurus polyzelus, which is based on a fragmentary specimen from Massachusetts. Two autapomorphies: dorsoventrally flattened ischial blades set at a low angle to each other and slender sacral ribs of the first sacral vertebra, link the holotype of A. polyzelus to the Manchester specimens. A revised diagnosis of the species and new skull reconstruction are presented. Recent anatomical observations of A. polyzelus indicate that several character states used to assess its phylogenetic position require revision. However, these are not sufficient to overturn previous cladistic analyses. A revised cladistic analysis continues to find support for Anchisaurus as a relatively derived basal sauropodomorph that lies outside of the clade Melanorosaurus + Sauropoda but is more closely related to it than to ‘core prosauropods’ such as Plateosaurus and Massospondylus.
The Origin and Early Radiation of Dinosaurs
Finally this is out, although presently only as an accepted manuscript in Earth Science Reviews. I was one of the reviewers for this paper and felt that it constitutes a very well written overview of early dinosaur work to the present, including many of the recent cool finds from the Chinle Formation of course. I was reviewing this manuscript last year about the time another early dinosaur review paper came out by Max Langer and colleagues (not sure why this paper is so delayed) and feel that these papers are nice complements to each other.
[Note: after writing this I noticed that Brusatte et al. added a similarily worded paragraph to the end of the introduction. I also noticed that they use the word "compliment" when they mean "complement". See the difference here ;)].
Brusatte, S. L., Nesbitt, S. J., Irmis, R. B., Butler, R. J., Benton, M. J., and M. A. Norell. 2010. The origin and early radiation of dinosaurs. Earth Science Reviews. Early online. doi: 10.1016/j.earscirev.2010.04.001
Abstract - Dinosaurs were remarkably successful during the Mesozoic and one subgroup, birds, remain an important component of modern ecosystems. Although the extinction of non-avian dinosaurs at the end of the Cretaceous has been the subject of intense debate, comparatively little attention has been given to the origin and early evolution of dinosaurs during the Late Triassic and Early Jurassic, one of the most important evolutionary radiations in earth history. Our understanding of this keystone event has dramatically changed over the past 25 years, thanks to an influx of new fossil discoveries, reinterpretations of long-ignored specimens, and quantitative macroevolutionary analyses that synthesize anatomical and geological data. Here we provide an overview of the first 50 million years of dinosaur history, with a focus on the large-scale patterns that characterize the ascent of dinosaurs from a small, almost marginal group of reptiles in the Late Triassic to the pre-eminent terrestrial vertebrates of the Jurassic and Cretaceous. We provide both a biological and geological background for early dinosaur history. Dinosaurs are deeply nested among the archosaurian reptiles, diagnosed by only a small number of characters, and are subdivided into a number of major lineages. The first unequivocal dinosaurs are known from the late Carnian of South America, but the presence of their sister group in the Middle Triassic implies that dinosaurs possibly originated much earlier. The three major dinosaur lineages, theropods, sauropodomorphs, and ornithischians, are all known from the Triassic, when continents were joined into the supercontinent Pangaea and global climates were hot and arid. Although many researchers have long suggested that dinosaurs outcompeted other reptile groups during the Triassic, we argue that the ascent of dinosaurs was more of a matter of contingency and opportunism. Dinosaurs were overshadowed in most Late Triassic ecosystems by crocodile-line archosaurs and showed no signs of outcompeting their rivals. Instead, the rise of dinosaurs was a two-stage process, as dinosaurs expanded in taxonomic diversity, morphological disparity, and absolute faunal abundance only after the extinction of most crocodile-line reptiles and other groups.
[Note: after writing this I noticed that Brusatte et al. added a similarily worded paragraph to the end of the introduction. I also noticed that they use the word "compliment" when they mean "complement". See the difference here ;)].
Brusatte, S. L., Nesbitt, S. J., Irmis, R. B., Butler, R. J., Benton, M. J., and M. A. Norell. 2010. The origin and early radiation of dinosaurs. Earth Science Reviews. Early online. doi: 10.1016/j.earscirev.2010.04.001
Abstract - Dinosaurs were remarkably successful during the Mesozoic and one subgroup, birds, remain an important component of modern ecosystems. Although the extinction of non-avian dinosaurs at the end of the Cretaceous has been the subject of intense debate, comparatively little attention has been given to the origin and early evolution of dinosaurs during the Late Triassic and Early Jurassic, one of the most important evolutionary radiations in earth history. Our understanding of this keystone event has dramatically changed over the past 25 years, thanks to an influx of new fossil discoveries, reinterpretations of long-ignored specimens, and quantitative macroevolutionary analyses that synthesize anatomical and geological data. Here we provide an overview of the first 50 million years of dinosaur history, with a focus on the large-scale patterns that characterize the ascent of dinosaurs from a small, almost marginal group of reptiles in the Late Triassic to the pre-eminent terrestrial vertebrates of the Jurassic and Cretaceous. We provide both a biological and geological background for early dinosaur history. Dinosaurs are deeply nested among the archosaurian reptiles, diagnosed by only a small number of characters, and are subdivided into a number of major lineages. The first unequivocal dinosaurs are known from the late Carnian of South America, but the presence of their sister group in the Middle Triassic implies that dinosaurs possibly originated much earlier. The three major dinosaur lineages, theropods, sauropodomorphs, and ornithischians, are all known from the Triassic, when continents were joined into the supercontinent Pangaea and global climates were hot and arid. Although many researchers have long suggested that dinosaurs outcompeted other reptile groups during the Triassic, we argue that the ascent of dinosaurs was more of a matter of contingency and opportunism. Dinosaurs were overshadowed in most Late Triassic ecosystems by crocodile-line archosaurs and showed no signs of outcompeting their rivals. Instead, the rise of dinosaurs was a two-stage process, as dinosaurs expanded in taxonomic diversity, morphological disparity, and absolute faunal abundance only after the extinction of most crocodile-line reptiles and other groups.
Triassic Life on Land: The Great Transition
Now I'm going to go do some more work so Hans and Nick will be forced to do an updated second edition next year ;).
Sues, H.-D., and N. C. Fraser. 2010. Triassic life on land: The Great Transistion. Columbia University Press, New York, 229p.
P.S. Why is there no aetosaur on the cover? Maybe it is hiding?
Sequence Stratigraphy of the Upper Triassic Succession in Algeria
Bourquin, S., Eschard, R., Hamouche, B. High-resolution sequence stratigraphy of Upper Triassic succession (Carnian - Rhaetian) of the Zarzaitine outcrops (Algeria): a model of fluvio-lacustrine deposits, African Earth Sciences (2010), doi: 10.1016/j.jafrearsci.2010.04.003
Abstract - The detailed facies analysis of the Zarzaitine outcrops (Illizi Basin in the In Amenas area of Algeria) allows the depositional environment of the Upper Triassic succession to be defined: braided rivers within an arid and humid alluvial plain, low sinuosity rivers within a humid alluvial plain, lake deposits and marginal sabkha. The description of the outcrops helps to define three types of genetic units from a proximal to a distal depositional environment: fluvial, fluvial-lacustrine and lacustrine. The spatial and temporal evolutions of the genetic unit were characterised by five specific stages from dry to humid climate conditions, inducing sediment supply and lake-level variations. During the first two stages (stage 1 and 2) under a dry climate, the lake level was low and sediments mostly by-passed and poorly preserved. During stages 3 and 4, an increase in humidity and rainfall induced a rise in the lake-level and the development of vegetation, as well as a decrease in the sediment supply, although the sediment preservation were then at its maximum. The last stage (stage 5) marked the beginning of a decrease in the humidity, the minimum of sediment supply and the maximum of the lake level. Therefore, the recognition and the description of genetic units within this fluviallacustrine environment help to demonstrate the interaction between climate, sediment supply and lake-level variation, at the scale of these units. Six stratigraphic cycles have been recognised in the vertically stacked genetic units and can be grouped in three megacycles (denoted as I, II and III). The first megacycle, attributed to Carnian to early Norian, corresponds to the base of braided river systems with some ephemeral channels developed in an arid environment where some aeolian deposits were preserved. It evolved trough time to humid conditions favouring the development of extensive floodplain, associated with hydromorphic soils, and perennial lake environments. During the Carnian times and Norian, the Zarzaitine area was not connected to the Berkine basin northward, a Hercynian unconformity palaeorelief forming a drainage divide. According to the directions of the palaeocurrents, the sediment provenances were mostly from the southwest and the north. The connection with the Berkine basin only occurred during the upper part of the megacycle II deposition, characterised by fluvio-lacustrine environments. The maximum flooding of the megacycle I, Norian in age, could be correlated with the early Norian maximum flooding observed on the Saharan platform. The late Norian-Rhaetian second megacycle was mostly a lacustrine environment associated with extensive floodplain, with the development of a hydromorphic palaeosol with root imprints attributed to a warm and humid climate. The maximum flooding episode of this second megacycle could be
attributed to the major marine trangression recorded in Algeria, during the Rhaetian, and
could be correlated with a relative sea-level rise. A dolomitic level, attributed to sabkha
environments, marks the beginning of the retrogradational trend of the third cycle,
attributed to the Rhaetian-Liassic. The palaeocurrent of the upper part of megacycle II
and of the megacycle III were always oriented toward the northeast, attesting that the
relief was located to the southwest.
Abstract - The detailed facies analysis of the Zarzaitine outcrops (Illizi Basin in the In Amenas area of Algeria) allows the depositional environment of the Upper Triassic succession to be defined: braided rivers within an arid and humid alluvial plain, low sinuosity rivers within a humid alluvial plain, lake deposits and marginal sabkha. The description of the outcrops helps to define three types of genetic units from a proximal to a distal depositional environment: fluvial, fluvial-lacustrine and lacustrine. The spatial and temporal evolutions of the genetic unit were characterised by five specific stages from dry to humid climate conditions, inducing sediment supply and lake-level variations. During the first two stages (stage 1 and 2) under a dry climate, the lake level was low and sediments mostly by-passed and poorly preserved. During stages 3 and 4, an increase in humidity and rainfall induced a rise in the lake-level and the development of vegetation, as well as a decrease in the sediment supply, although the sediment preservation were then at its maximum. The last stage (stage 5) marked the beginning of a decrease in the humidity, the minimum of sediment supply and the maximum of the lake level. Therefore, the recognition and the description of genetic units within this fluviallacustrine environment help to demonstrate the interaction between climate, sediment supply and lake-level variation, at the scale of these units. Six stratigraphic cycles have been recognised in the vertically stacked genetic units and can be grouped in three megacycles (denoted as I, II and III). The first megacycle, attributed to Carnian to early Norian, corresponds to the base of braided river systems with some ephemeral channels developed in an arid environment where some aeolian deposits were preserved. It evolved trough time to humid conditions favouring the development of extensive floodplain, associated with hydromorphic soils, and perennial lake environments. During the Carnian times and Norian, the Zarzaitine area was not connected to the Berkine basin northward, a Hercynian unconformity palaeorelief forming a drainage divide. According to the directions of the palaeocurrents, the sediment provenances were mostly from the southwest and the north. The connection with the Berkine basin only occurred during the upper part of the megacycle II deposition, characterised by fluvio-lacustrine environments. The maximum flooding of the megacycle I, Norian in age, could be correlated with the early Norian maximum flooding observed on the Saharan platform. The late Norian-Rhaetian second megacycle was mostly a lacustrine environment associated with extensive floodplain, with the development of a hydromorphic palaeosol with root imprints attributed to a warm and humid climate. The maximum flooding episode of this second megacycle could be
attributed to the major marine trangression recorded in Algeria, during the Rhaetian, and
could be correlated with a relative sea-level rise. A dolomitic level, attributed to sabkha
environments, marks the beginning of the retrogradational trend of the third cycle,
attributed to the Rhaetian-Liassic. The palaeocurrent of the upper part of megacycle II
and of the megacycle III were always oriented toward the northeast, attesting that the
relief was located to the southwest.
The Phylogenetic Relationships of Eucynodontia
Liu, J., and P. Olsen. 2010. The Phylogenetic Relationships of Eucynodontia (Amniota: Synapsida). Journal of Mammalian Evolution. Published online April 13 2010. doi: 10.1007/s10914-010-9136-8
Abstract - The phylogeny of Eucynodontia is an important topic in vertebrate paleontology and is the foundation for understanding the origin of mammals. However, consensus on the phylogeny of Eucynodontia remains elusive. To clarify their interrelationships, a cladistic analysis, based on 145 characters and 31 species, and intergrating most prior works, was performed. The monophyly of Eucynodontia is confirmed, although the results slightly differ from those of previous analyses with respect to the composition of both Cynognathia and Probainognathia. This is also the first numerical cladistic analysis to recover a monophyletic Traversodontidae. Brasilodon is the plesiomorphic sister taxon of Mammalia, although it is younger than the oldest mammals and is specialized in some characters. A monophyletic Prozostrodontia, including tritheledontids, tritylodontids, and mammals, is well supported by many characters. Pruning highly incomplete taxa generally has little effect on the inferred pattern of relationships among the more complete taxa, although exceptions sometimes occur when basal fragmentary taxa are removed. Taxon sampling of the current data matrix shows that taxon sampling was poor in some previous studies, implying that their results are not reliable. Two major unresolved questions in cynodont phylogenetics are whether tritylodontids are more closely related to mammals or to traversodontids, and whether tritylodontids or tritheledontids are closer to mammals. Analyses of possible synapomorphies support a relatively close relationship between mammals and tritylodontids, to the exclusion of traversodontids, but do not clearly indicate whether or not tritheledontids are closer to mammals than are tritylodontids.
Abstract - The phylogeny of Eucynodontia is an important topic in vertebrate paleontology and is the foundation for understanding the origin of mammals. However, consensus on the phylogeny of Eucynodontia remains elusive. To clarify their interrelationships, a cladistic analysis, based on 145 characters and 31 species, and intergrating most prior works, was performed. The monophyly of Eucynodontia is confirmed, although the results slightly differ from those of previous analyses with respect to the composition of both Cynognathia and Probainognathia. This is also the first numerical cladistic analysis to recover a monophyletic Traversodontidae. Brasilodon is the plesiomorphic sister taxon of Mammalia, although it is younger than the oldest mammals and is specialized in some characters. A monophyletic Prozostrodontia, including tritheledontids, tritylodontids, and mammals, is well supported by many characters. Pruning highly incomplete taxa generally has little effect on the inferred pattern of relationships among the more complete taxa, although exceptions sometimes occur when basal fragmentary taxa are removed. Taxon sampling of the current data matrix shows that taxon sampling was poor in some previous studies, implying that their results are not reliable. Two major unresolved questions in cynodont phylogenetics are whether tritylodontids are more closely related to mammals or to traversodontids, and whether tritylodontids or tritheledontids are closer to mammals. Analyses of possible synapomorphies support a relatively close relationship between mammals and tritylodontids, to the exclusion of traversodontids, but do not clearly indicate whether or not tritheledontids are closer to mammals than are tritylodontids.
Biogeography of Triassic tetrapods
Interesting approach and personally timely as I just happen to really be into Triassic biogeography at the moment; however, I think this study suffers somewhat from the usual culprits, lack of taxon sampling and unresolved taxonomic issues (weak primary data). For example, basal phytosaurs are completely left out which have an early and widespread appearance in the Late Triassic. These are extremely important as they are found in Europe, North America, North Africa, and interestingly in India. Including these would have changed several of the paper's conclusions. Likewise, the aetosaur Calyptosuchus (Stagonolepis) wellesi is purposefully left out as is Coahomasuchus, which are two important datapoints for aetosaurs in the Ischigualastian of North America. I wish I had been contacted regarding this study as I would have gladly suggested some less "key" aetosaur taxa to leave out if better resolution was needed for the basal aetosaurines. It is also not entirely clear if the Ischigulastian and Coloradian are applicable outside of South America. It appears that they are presented as equivalent to the Otischalkian + Adamanian and Revueltian + Apachean of North America. This was first put forth by Max Langer in 2005 and has some support, but needs further testing, especially regarding the relationships of all of the Stagonolepis-like aetosaurs, the lack of good phytosaur material in South America, and lack of good (or any) comparable rhynchosaur, cynodont, and sauropodomorph material in North America.
On a side note, it was nice to see Heliocanthus used in there.
Ezcurra, M. D. 2010. Biogeography of Triassic tetrapods: evidence for provincialism and driven sympatric cladogenesis in the early evolution of modern tetrapod lineages. Proceedings of the Royal Society B, doi:10.1098/rspb.2010.0508 Published online.
Abstract - Triassic tetrapods are of key importance in understanding their evolutionary history, because several tetrapod clades, including most of their modern lineages, first appeared or experienced their initial evolutionary radiation during this Period. In order to test previous palaeobiogeographical hypotheses of Triassic tetrapod faunas, tree reconciliation analyses (TRA) were performed with the aim of recovering biogeographical patterns based on phylogenetic signals provided by a composite tree of Middle and Late Triassic tetrapods. The TRA found significant evidence for the presence of different palaeobiogeographical patterns during the analysed time spans. First, a Pangaean distribution is observed during the Middle Triassic, in which several cosmopolitan tetrapod groups are found. During the early Late Triassic a strongly palaeolatitudinally influenced pattern is recovered, with some tetrapod lineages restricted to palaeolatitudinal belts. During the latest Triassic, Gondwanan territories were more closely related to each other than to Laurasian ones, with a distinct tetrapod fauna at low palaeolatitudes. Finally, more than 75 per cent of the cladogenetic events recorded in the tetrapod phylogeny occurred as sympatric splits or within-area vicariance, indicating that evolutionary processes at the regional level were the main drivers in the radiation of Middle and Late Triassic tetrapods and the early evolution of several modern tetrapod lineages.
On a side note, it was nice to see Heliocanthus used in there.
Ezcurra, M. D. 2010. Biogeography of Triassic tetrapods: evidence for provincialism and driven sympatric cladogenesis in the early evolution of modern tetrapod lineages. Proceedings of the Royal Society B, doi:10.1098/rspb.2010.0508 Published online.
Abstract - Triassic tetrapods are of key importance in understanding their evolutionary history, because several tetrapod clades, including most of their modern lineages, first appeared or experienced their initial evolutionary radiation during this Period. In order to test previous palaeobiogeographical hypotheses of Triassic tetrapod faunas, tree reconciliation analyses (TRA) were performed with the aim of recovering biogeographical patterns based on phylogenetic signals provided by a composite tree of Middle and Late Triassic tetrapods. The TRA found significant evidence for the presence of different palaeobiogeographical patterns during the analysed time spans. First, a Pangaean distribution is observed during the Middle Triassic, in which several cosmopolitan tetrapod groups are found. During the early Late Triassic a strongly palaeolatitudinally influenced pattern is recovered, with some tetrapod lineages restricted to palaeolatitudinal belts. During the latest Triassic, Gondwanan territories were more closely related to each other than to Laurasian ones, with a distinct tetrapod fauna at low palaeolatitudes. Finally, more than 75 per cent of the cladogenetic events recorded in the tetrapod phylogeny occurred as sympatric splits or within-area vicariance, indicating that evolutionary processes at the regional level were the main drivers in the radiation of Middle and Late Triassic tetrapods and the early evolution of several modern tetrapod lineages.
Blogroll Updates
I am well aware that many of the hits I get to this site are to access my blogroll, so I try to update it somewhat regularly to add sites that my readers (or myself) seem to be interested in. Just today I've added two more that I think may be of interest to at least some of you.
Crurotarsi: the Forgotten Archosaurs
http://forgottenarchosaurs.blogspot.com/
Tom Holtz first mentioned and gave us the following update on this site on his Facebook page, that this new blog (2 posts old at this writing) is by "a former undergrad of mine, Susan Drymala, who hopes to eventually go on to grad school working on crurotarsans/pseudosuchians. She figured starting a blog about them would be a good way to learn."
I'm personally grateful to Tom for slipping the term Pseudosuchia in there.
Another new blogroll item is what I think is the funniest blog I've ever read:
Hyperbole and a Half
http://hyperboleandahalf.blogspot.com/
This site pretty much contains the hilarious random musings and artwork of Allie Brosh who started up this blog last summer because "I was procrastinating on studying for a physics final and I was like "I know what would be a good idea! I'm going to start a blog!" So I started a blog." She already has over 2000 followers and two million hits! I'll warn you, her site is very funny and very addictive. She does occasionally cover dinosaurs....
Finally, as some may be aware I have my own Civil War History blog on the History of the 1st Connecticut Voluteer Regiment, a unit that is poorly documented and that I have been accumulating information on for more than two decades.
Three Month Men
http://threemonthmen.blogspot.com/
I try to post something new every two weeks and you could just click on it to get my hits up, but I hope anyone who is a U.S. History buff may find it of interest. I don't cover dinosaurs there...
Go ahead and check these all out.
Crurotarsi: the Forgotten Archosaurs
http://forgottenarchosaurs.blogspot.com/
Tom Holtz first mentioned and gave us the following update on this site on his Facebook page, that this new blog (2 posts old at this writing) is by "a former undergrad of mine, Susan Drymala, who hopes to eventually go on to grad school working on crurotarsans/pseudosuchians. She figured starting a blog about them would be a good way to learn."
I'm personally grateful to Tom for slipping the term Pseudosuchia in there.
Another new blogroll item is what I think is the funniest blog I've ever read:
Hyperbole and a Half
http://hyperboleandahalf.blogspot.com/
This site pretty much contains the hilarious random musings and artwork of Allie Brosh who started up this blog last summer because "I was procrastinating on studying for a physics final and I was like "I know what would be a good idea! I'm going to start a blog!" So I started a blog." She already has over 2000 followers and two million hits! I'll warn you, her site is very funny and very addictive. She does occasionally cover dinosaurs....
Finally, as some may be aware I have my own Civil War History blog on the History of the 1st Connecticut Voluteer Regiment, a unit that is poorly documented and that I have been accumulating information on for more than two decades.
Three Month Men
http://threemonthmen.blogspot.com/
I try to post something new every two weeks and you could just click on it to get my hits up, but I hope anyone who is a U.S. History buff may find it of interest. I don't cover dinosaurs there...
Go ahead and check these all out.
New Biostratigraphical Constraints for the Norian⁄Rhaetian Boundary
Once even questioned as a valid stage the Rhaetian has made quite a comeback research-wise, especially since the GSSP for the Norian/Rhaetian boundary has yet to be determined.
Giordano, N., Rigo, M., Ciarapica G. & Bertinelli A. 2010. New biostratigraphical constraints for the Norian ⁄Rhaetian boundary: data from Lagonegro Basin, Southern Apennines, Italy. Lethaia, 10.1111/j.1502-3931.2010.00219.x.
Abstract - Four stratigraphic sections belonging to Lagonegro succession (Southern Apennines) at Mt S. Enoc, Pignola-Abriola, Sasso di Castalda and Mt Volturino have been studied in detail under to provide a new micro-palaeontological data set based on conodonts and radiolarians for the characterization of the Norian ⁄Rhaetian interval. The studied sections represent the different settings of the Lagonegro Basin (from proximal to distal facies) and permit a detailed, integrated, biostratigraphy of the Calcari con Selce (cherty limestones) and Scisti Silicei formations (bedded cherts with radiolarians) to be drawn up. The upper portion of the Calcari con Selce Formation, exhibits intermediate characteristics between the Calcari con Selce and Scisti Silicei Formation, in particular the progressive decrease in carbonate content against an increase in shales and cherts. Within the four sections studied, the Norian ⁄Rhaetian interval has been documented both with conodonts and radiolarians. Because of the continuity and the absence of condensed facies, it has been possible to recognize the morphocline between species Misikella hernsteini and Misikella posthernsteini, here represented by all the transitional forms characterized by common features between the two species, gathered in three evolutionary steps. Moreover, the morphocline between M. hernsteini and M. posthernsteini has been involved in the definition of the Norian ⁄ Rhaetian Boundary, recognizing thus the FAD of M. posthernsteini, one of the possible biomarkers proposed for the boundary. The rich, well-preserved, radiolarian associations of Pignola-Abriola, Sasso di Castalda and Mt Volturino permit the correlation of Tethyan and American conodont successions, highlighting the importance of the mostly coincident occurrences of M. posthernsteini and Epigondolella mosheri morphotype A, which correspond to the base of Proparvicingula moniliformis A. Z. and the disappearance of bivalve Monotis. These coincident bioevents are used here to define the base of the Rhaetian stage.
Giordano, N., Rigo, M., Ciarapica G. & Bertinelli A. 2010. New biostratigraphical constraints for the Norian ⁄Rhaetian boundary: data from Lagonegro Basin, Southern Apennines, Italy. Lethaia, 10.1111/j.1502-3931.2010.00219.x.
Abstract - Four stratigraphic sections belonging to Lagonegro succession (Southern Apennines) at Mt S. Enoc, Pignola-Abriola, Sasso di Castalda and Mt Volturino have been studied in detail under to provide a new micro-palaeontological data set based on conodonts and radiolarians for the characterization of the Norian ⁄Rhaetian interval. The studied sections represent the different settings of the Lagonegro Basin (from proximal to distal facies) and permit a detailed, integrated, biostratigraphy of the Calcari con Selce (cherty limestones) and Scisti Silicei formations (bedded cherts with radiolarians) to be drawn up. The upper portion of the Calcari con Selce Formation, exhibits intermediate characteristics between the Calcari con Selce and Scisti Silicei Formation, in particular the progressive decrease in carbonate content against an increase in shales and cherts. Within the four sections studied, the Norian ⁄Rhaetian interval has been documented both with conodonts and radiolarians. Because of the continuity and the absence of condensed facies, it has been possible to recognize the morphocline between species Misikella hernsteini and Misikella posthernsteini, here represented by all the transitional forms characterized by common features between the two species, gathered in three evolutionary steps. Moreover, the morphocline between M. hernsteini and M. posthernsteini has been involved in the definition of the Norian ⁄ Rhaetian Boundary, recognizing thus the FAD of M. posthernsteini, one of the possible biomarkers proposed for the boundary. The rich, well-preserved, radiolarian associations of Pignola-Abriola, Sasso di Castalda and Mt Volturino permit the correlation of Tethyan and American conodont successions, highlighting the importance of the mostly coincident occurrences of M. posthernsteini and Epigondolella mosheri morphotype A, which correspond to the base of Proparvicingula moniliformis A. Z. and the disappearance of bivalve Monotis. These coincident bioevents are used here to define the base of the Rhaetian stage.
The Oldest Fossil Feather from Europe
No it's not Triassic, but I'll bet I got a few hearts racing with that title on this blog! Anyhow, I couldn't resist, plus I'm not really sure what I think of this. I'm just seeing a smear, but then again I'm not a fossil feather expert. What do you think?
Schweigert, G., Tischlinger, H. & Dietl, G. 2009. The oldest fossil feather from Europe. Neues Jahrbuch für Geologie und Paläontologie, Abh., DOI: 10.1127/0077-7749/2009/0061.
Abstract: We describe a fossil feather from Nusplingen, an Upper Jurassic Solnhofen-type Fossil - lagerstätte in SW Germany. It is Late Kimmeridgian in age and thus stratigraphically older than the isolated Archaeopteryx feather from the Lower Tithonian of Solnhofen, Bavaria, described in 1861. The features of the new find are unique, therefore it is impossible to identify the animal from which this feather came, but despite this uncertainty, the specimen may play an important role in our understanding of the evolution of feathers.
Schweigert, G., Tischlinger, H. & Dietl, G. 2009. The oldest fossil feather from Europe. Neues Jahrbuch für Geologie und Paläontologie, Abh., DOI: 10.1127/0077-7749/2009/0061.
Abstract: We describe a fossil feather from Nusplingen, an Upper Jurassic Solnhofen-type Fossil - lagerstätte in SW Germany. It is Late Kimmeridgian in age and thus stratigraphically older than the isolated Archaeopteryx feather from the Lower Tithonian of Solnhofen, Bavaria, described in 1861. The features of the new find are unique, therefore it is impossible to identify the animal from which this feather came, but despite this uncertainty, the specimen may play an important role in our understanding of the evolution of feathers.
from Schweigert et al. 2010
There is Only One Way to Study an Aetosaur.....
and that is to lay them out.
This is Texas Memorial Museum (TMM) specimen 31185-84B, the lectotype of Longosuchus meadei from the Dockum Group of Texas.
The Permian-Triassic Global Extinction Was Possibly Not Global
Hochuli, P. A., Os Vigran, J., Hermann, E., and H. Bucher. 2010. Multiple climatic changes around the Permian-Triassic boundary event revealed by an expanded palynological record from mid-Norway. Geological Society of America Bulletin 122:884-896. doi: 10.1130/B26551.1
Abstract - Here, we present the palynological record from two shallow core holes(6611/09-U-01 and -02) from the Trøndelag Platform offshore mid-Norway consisting of 750 m of Upper Permian and Lower Triassic sediments. The relatively homogeneous assemblages recovered from the Upper Permian deposits are dominated by gymnosperm pollen, mainly pteridosperms. At the base of the Griesbachian, numerous spore species appear in the record, leading to an increased diversity. The change at this boundary is also marked by the massive reduction of one group of pteridosperm pollen (Vittatina). Together with other typical Permianelements (e.g., Lueckisporites virkkiae), this group is rare but consistently present in the lower part of the Griesbachian, and it gradually disappears in its upper part. The distribution of other groups such as taeniate and non-taeniate bisaccate gymnosperm pollen (pterido sperms and conifers) shows no significant change across the boundary, whereas spores and other gymnosperm pollen increase in diversity and abundance. These changes coincide with the formational change between the Schuchert Dal Formation (Upper Permian) and the Wordie Creek Formation (Griesbachian) equivalents. Late Permian and Griesbachian palynomorph assemblages display different patterns. The former show a homogeneous composition of low diversity, whereas the latter reflect diverse and variably composed floras. The data suggest that the arid phase of the Late Permian was followed by a humid phase at the base of the Griesbachian. In the Griesbachian section, a succession of six distinct palynological assemblages (phase II–VII) can be inferred. Comparable changes have been described from East Greenland. The variations in the palynological record are interpreted to reflect changing ecological conditions (e.g., changing humidity). Comparable variations in the distribution of δ13C isotope values reported from various sections from Greenland and China, showing stable values during the Late Permian and highly variable values during the Griesbachian, suggest common causes for the observed fluctuations. Multiphase volcanic activity of the Siberian traps seems to be the most likely candidate to have caused the variations in the δ13C isotope as well as in the palynological record. In contrast to the common claim that marine and terrestrial biota both suffered a mass extinction related to the Permian- Triassic boundary event, the studied material from the Norwegian midlatitudinal sites shows no evidence for destruction of plant ecosystems. The presence of diverse microfloras of Griesbachian age supports the idea that the climate in this area allowed most plants to survive the Permian-Triassic boundary event.
Abstract - Here, we present the palynological record from two shallow core holes(6611/09-U-01 and -02) from the Trøndelag Platform offshore mid-Norway consisting of 750 m of Upper Permian and Lower Triassic sediments. The relatively homogeneous assemblages recovered from the Upper Permian deposits are dominated by gymnosperm pollen, mainly pteridosperms. At the base of the Griesbachian, numerous spore species appear in the record, leading to an increased diversity. The change at this boundary is also marked by the massive reduction of one group of pteridosperm pollen (Vittatina). Together with other typical Permianelements (e.g., Lueckisporites virkkiae), this group is rare but consistently present in the lower part of the Griesbachian, and it gradually disappears in its upper part. The distribution of other groups such as taeniate and non-taeniate bisaccate gymnosperm pollen (pterido sperms and conifers) shows no significant change across the boundary, whereas spores and other gymnosperm pollen increase in diversity and abundance. These changes coincide with the formational change between the Schuchert Dal Formation (Upper Permian) and the Wordie Creek Formation (Griesbachian) equivalents. Late Permian and Griesbachian palynomorph assemblages display different patterns. The former show a homogeneous composition of low diversity, whereas the latter reflect diverse and variably composed floras. The data suggest that the arid phase of the Late Permian was followed by a humid phase at the base of the Griesbachian. In the Griesbachian section, a succession of six distinct palynological assemblages (phase II–VII) can be inferred. Comparable changes have been described from East Greenland. The variations in the palynological record are interpreted to reflect changing ecological conditions (e.g., changing humidity). Comparable variations in the distribution of δ13C isotope values reported from various sections from Greenland and China, showing stable values during the Late Permian and highly variable values during the Griesbachian, suggest common causes for the observed fluctuations. Multiphase volcanic activity of the Siberian traps seems to be the most likely candidate to have caused the variations in the δ13C isotope as well as in the palynological record. In contrast to the common claim that marine and terrestrial biota both suffered a mass extinction related to the Permian- Triassic boundary event, the studied material from the Norwegian midlatitudinal sites shows no evidence for destruction of plant ecosystems. The presence of diverse microfloras of Griesbachian age supports the idea that the climate in this area allowed most plants to survive the Permian-Triassic boundary event.
Further Support for a Causal Relationship Between the CAMP and the End-Triassic Extinction Event
Deenen, M. H. L., Ruhl, M., Bonis, M. R., Krijgsman, W., Kuerschner, W. M., Reitsma, M. and M. J. van Bergen. 2010. A new chronology for the end-Triassic mass extinction. Earth and Planetary Science Letters 291:113–125. doi:10.1016/j.epsl.2010.01.003
Abstract - The transition from the Triassic to Jurassic Period, initiating the ‘Age of the dinosaurs’, approximately 200 Ma, is marked by a profound mass extinction with more than 50% genus loss in both marine and continental realms. This event closely coincides with a period of extensive volcanism in the Central Atlantic Magmatic Province (CAMP) associated with the initial break-up of Pangaea but a causal relationship is still debated. The Triassic–Jurassic (T–J) boundary is recently proposed in the marine record at the first occurrence datum of Jurassic ammonites, post-dating the extinction interval that concurs with two distinct perturbations in the carbon isotope record. The continental record shows a major palynological turnover together with a prominent change in tetrapod taxa, but a direct link to the marine events is still equivocal. Here we develop
an accurate chronostratigraphic framework for the T–J boundary interval and establish detailed trans-Atlantic and marine–continental correlations by integrating astrochronology, paleomagnetism, basalt geochemistry and geobiology. We show that the oldest CAMP basalts are diachronous by 20 kyr across the Atlantic Ocean, and that these two volcanic pulses coincide with the end-Triassic extinction interval in the marine realm. Our results support the hypotheses of Phanerozoic mass extinctions resulting from emplacement of Large Igneous Provinces (LIPs) and provide crucial time constraints for numerical modelling of Triassic–Jurassic climate change and global carbon-cycle perturbations.
Abstract - The transition from the Triassic to Jurassic Period, initiating the ‘Age of the dinosaurs’, approximately 200 Ma, is marked by a profound mass extinction with more than 50% genus loss in both marine and continental realms. This event closely coincides with a period of extensive volcanism in the Central Atlantic Magmatic Province (CAMP) associated with the initial break-up of Pangaea but a causal relationship is still debated. The Triassic–Jurassic (T–J) boundary is recently proposed in the marine record at the first occurrence datum of Jurassic ammonites, post-dating the extinction interval that concurs with two distinct perturbations in the carbon isotope record. The continental record shows a major palynological turnover together with a prominent change in tetrapod taxa, but a direct link to the marine events is still equivocal. Here we develop
an accurate chronostratigraphic framework for the T–J boundary interval and establish detailed trans-Atlantic and marine–continental correlations by integrating astrochronology, paleomagnetism, basalt geochemistry and geobiology. We show that the oldest CAMP basalts are diachronous by 20 kyr across the Atlantic Ocean, and that these two volcanic pulses coincide with the end-Triassic extinction interval in the marine realm. Our results support the hypotheses of Phanerozoic mass extinctions resulting from emplacement of Large Igneous Provinces (LIPs) and provide crucial time constraints for numerical modelling of Triassic–Jurassic climate change and global carbon-cycle perturbations.
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