Buchwitz, M., Witzmann, F., Voigt, S. and Golubev, V. 2011. Osteoderm microstructure indicates the presence of a crocodylian-like trunk bracing system in a group of armoured basal tetrapods. Acta Zoologica (Stockholm) 00:1–21. DOI: 10.1111/j.1463-6395.2011.00502.x
Abstract - The microstructure of dorsal osteoderms referred to the chroniosuchid taxa Chroniosuchus, Chroniosaurus, Madygenerpeton and cf. Uralerpeton is compared to existing data on the bystrowianid chroniosuchian Bystrowiella and further tetrapods. Chroniosuchid osteoderms are marked by thin internal and relatively thick external cortices that consist of lowly vascularised parallel-fibred bone. They are structured by growth marks and, in case of Madygenerpeton, by lines of arrested growth. The cancellous middle region is marked by a high degree of remodelling and a primary bone matrix of parallel-fibred bone that may include domains of interwoven structural fibres. Whereas the convergence of Bystrowiella and chroniosuchid osteoderms is not confirmed by our observations, the internal cortex of the latter displays a significant peculiarity: It contains distinct bundles of shallowly dipping Sharpey’s fibres with a cranio- or caudoventral orientation. We interpret this feature as indicative for the attachment of epaxial muscles which spanned several vertebral segments between the medioventral surface of the osteoderms and the transversal processes of the thoracic vertebrae. This finding endorses the hypothesis that the chroniosuchid osteoderm series was part of a crocodylian-like trunk bracing system that supported terrestrial locomotion. According to the measured range of osteoderm bone compactness, some chroniosuchian species may have had a more aquatic lifestyle than others.
Middle Triassic Lobsters from the Netherlands
Klompmaker, A. A., and R. H. B. Fraaije. 2011. The oldest (Middle Triassic, Anisian) lobsters from the Netherlands: taxonomy, taphonomy, paleoenvironment, and paleoecology. Palaeontologia Electronica 14.1.1A.
Abstract - Fossil lobsters from the Netherlands have been described only rarely. This article describes the oldest, marine lobsters from the Netherlands in Middle Triassic Anisian (Muschelkalk) sediments cropping out in the Winterswijk quarry complex. The lobsters include the erymids Clytiopsis argentoratensis and Oosterinkia neerlandica n. gen., n. sp., and the mecochirid Pseudoglyphea cf. P. spinosa. They lived in a low energy, stressed environment with fluctuating salinity levels. This fluctuation might have caused the limited size of the specimens of Clytiopsis argentoratensis compared to related stratigraphically younger and older lobsters. In addition, the low number of specimens collected over decades and the low number of crustacean species is likely to be caused by a combination of the environment itself and a limited preservation potential.
Abstract - Fossil lobsters from the Netherlands have been described only rarely. This article describes the oldest, marine lobsters from the Netherlands in Middle Triassic Anisian (Muschelkalk) sediments cropping out in the Winterswijk quarry complex. The lobsters include the erymids Clytiopsis argentoratensis and Oosterinkia neerlandica n. gen., n. sp., and the mecochirid Pseudoglyphea cf. P. spinosa. They lived in a low energy, stressed environment with fluctuating salinity levels. This fluctuation might have caused the limited size of the specimens of Clytiopsis argentoratensis compared to related stratigraphically younger and older lobsters. In addition, the low number of specimens collected over decades and the low number of crustacean species is likely to be caused by a combination of the environment itself and a limited preservation potential.
New Skull Material from an Early Triassic Procolophonid
Macdougall, M. J., and S. P. Modesto. 2011. New information on the skull of the Early Triassic parareptile Sauropareion anoplus, with a discussion of tooth attachment and replacement in procolophonids. Journal of Vertebrate Paleontology 31:270-278. DOI: 10.1080/02724634.2011.549436
Abstract- A partial reptile skull collected from the Lower Triassic (Induan) Barendskraal locality of South Africa is referable to the procolophonid parareptile Sauropareion anoplus. The specimen comprises the left side of the skull roof, palate, and mandible, and preserves areas not preserved or accessible in the skulls of previously published specimens, including fragmentary remains of the premaxilla, the anterior end of the maxilla, and the anterior end and lingual aspect of the mandible. The maxilla exhibits a maxillary depression that is similar in both shape and relative size to that seen in Procolophon trigoniceps, an anterolateral maxillary foramen that is indistinguishable from those seen in other procolophonoids, and 11 conical teeth. The suborbital foramen is formed ventrally by the palatine and the ectopterygoid. The dentary and the coronoid are fused together indistinguishably in lateral aspect. The marginal teeth appear to be anchored to the jaws by bone of attachment. The dentary teeth are exposed in lingual aspect and appear to be ankylosed to the summit of the bone, suggesting acrodont tooth implantation. Tooth replacement is seen in these teeth, where the lingual surface of a single tooth crown base in the middle of the dentary series is excavated for the apex of a replacement tooth crown, but the excavation does not extend ventrally onto the lingual surface of the bone. Considering that no extant reptiles with acrodont tooth implantation exhibit tooth replacement or bone of attachment, we tentatively regard protothecodonty to be present in S. anoplus.
Abstract- A partial reptile skull collected from the Lower Triassic (Induan) Barendskraal locality of South Africa is referable to the procolophonid parareptile Sauropareion anoplus. The specimen comprises the left side of the skull roof, palate, and mandible, and preserves areas not preserved or accessible in the skulls of previously published specimens, including fragmentary remains of the premaxilla, the anterior end of the maxilla, and the anterior end and lingual aspect of the mandible. The maxilla exhibits a maxillary depression that is similar in both shape and relative size to that seen in Procolophon trigoniceps, an anterolateral maxillary foramen that is indistinguishable from those seen in other procolophonoids, and 11 conical teeth. The suborbital foramen is formed ventrally by the palatine and the ectopterygoid. The dentary and the coronoid are fused together indistinguishably in lateral aspect. The marginal teeth appear to be anchored to the jaws by bone of attachment. The dentary teeth are exposed in lingual aspect and appear to be ankylosed to the summit of the bone, suggesting acrodont tooth implantation. Tooth replacement is seen in these teeth, where the lingual surface of a single tooth crown base in the middle of the dentary series is excavated for the apex of a replacement tooth crown, but the excavation does not extend ventrally onto the lingual surface of the bone. Considering that no extant reptiles with acrodont tooth implantation exhibit tooth replacement or bone of attachment, we tentatively regard protothecodonty to be present in S. anoplus.
Another North American Triassic Dinosaur that Wasn't
Holbrook, Arizona is a small little city of barely 5,000 people along Interstate 40 in Northeastern Arizona and is where I call home because it is the closest city to the Petrified Forest National Park. It's a neat little place, an old Route 66 town (this sign is visible from my home) with an even older bloody wild west history.
The local paper, the Holbrook Tribune, has a weekly feature where they reprint news snippets from the last 10, 25, 50, and 75 years. This one caught my eye in last Friday's edition.
"25 Years Ago - The oldest articulated dinosaur was named after Holbrook, according to Petrified Forest National Park Superintendent Ed Gastellum. Known affectionately as "Gertie," its official name was Holbrookosauras Smallii, honoring the community of Holbrook and Brian [sic] Small, the discoverer of the remains at the Petrified Forest."
Twenty five years ago, 1986, marked nearly a year since the specimen was collected in the most spectacular manner. I had always thought that the first unofficial name applied to the specimen was the nomen nudum "Chindesaurus bryansmalli" by Murry and Long (1989) but it looks like "Holbrookosauras smallii" beat it by several years.
Obviously the valid name for this specimen today is Chindesaurus bryansmalli Long and Murry 1995. The name Chindesaurus is derived from Chinde (Navajo for ghost or spirit) Point in Petrified Forest National Park, near where the specimen was collected.
So it appears that for some reason the City of Holbrook lost out on their dinosaur name. Fortunately, they did just get a style of new Oakley brand sunglasses designed by professional snowboarder Shaun White named for the town so all is not lost, and there are still tons of fossils waiting to be discovered out there in the Chinle Formation, including the elusive Triassic dinosaurs; so their day still may come. Next time we will get the spelling right though ;).
The local paper, the Holbrook Tribune, has a weekly feature where they reprint news snippets from the last 10, 25, 50, and 75 years. This one caught my eye in last Friday's edition.
"25 Years Ago - The oldest articulated dinosaur was named after Holbrook, according to Petrified Forest National Park Superintendent Ed Gastellum. Known affectionately as "Gertie," its official name was Holbrookosauras Smallii, honoring the community of Holbrook and Brian [sic] Small, the discoverer of the remains at the Petrified Forest."
Twenty five years ago, 1986, marked nearly a year since the specimen was collected in the most spectacular manner. I had always thought that the first unofficial name applied to the specimen was the nomen nudum "Chindesaurus bryansmalli" by Murry and Long (1989) but it looks like "Holbrookosauras smallii" beat it by several years.
Obviously the valid name for this specimen today is Chindesaurus bryansmalli Long and Murry 1995. The name Chindesaurus is derived from Chinde (Navajo for ghost or spirit) Point in Petrified Forest National Park, near where the specimen was collected.
So it appears that for some reason the City of Holbrook lost out on their dinosaur name. Fortunately, they did just get a style of new Oakley brand sunglasses designed by professional snowboarder Shaun White named for the town so all is not lost, and there are still tons of fossils waiting to be discovered out there in the Chinle Formation, including the elusive Triassic dinosaurs; so their day still may come. Next time we will get the spelling right though ;).
A New South African Therapsid in the Newest Issue of JVP
Quite a few Triassic papers in the new issue of JVP. Here is one:
Huttenlocker, A. K., Sidor, C. A., and R. M. H. Smith. 2011. A new specimen of Promoschorhynchus (Therapsida: Therocephalia: Akidnognathidae) from the Lower Triassic of South Africa and its implications for theriodont survivorship across the Permo-Triassic boundary. Journal of Vertebrate Paleontology 31:405-421. DOI: 10.1080/02724634.2011.546720
Abstract - The anatomy of a new subadult specimen of eutherocephalian therapsid, attributed to Promoschorhynchus cf. P. platyrhinus, is described from lowermost Triassic Lystrosaurus Assemblage Zone strata in the main Karoo Basin of South Africa. The specimen preserves information previously unknown in the genus, including details of the posterior region of the skull and intertemporal region, and a partial (though disarticulated) postcranial skeleton. A cladistic analysis of 32 therapsid taxa, including 24 Permo-Triassic therocephalian genera, and 121 craniodental and postcranial characters supports the specimen's placement within the Permian akidnognathid genus Promoschorhynchus (making it the youngest documented occurrence of this taxon) within a monophyletic Therocephalia. Inclusion of new postcranial characters strengthens support of the therocephalian clade. The new record of Promoschorhynchus offers insights into the diversity of eutheriodonts across the Permo-Triassic boundary (PTB) in the Karoo Basin. In contrast to cynodonts, therocephalians exhibited decreased rates of cladogenesis across the PTB, with several Triassic lineages having roots in the Late Permian rather than representing earliest Triassic radiations.
Huttenlocker, A. K., Sidor, C. A., and R. M. H. Smith. 2011. A new specimen of Promoschorhynchus (Therapsida: Therocephalia: Akidnognathidae) from the Lower Triassic of South Africa and its implications for theriodont survivorship across the Permo-Triassic boundary. Journal of Vertebrate Paleontology 31:405-421. DOI: 10.1080/02724634.2011.546720
Abstract - The anatomy of a new subadult specimen of eutherocephalian therapsid, attributed to Promoschorhynchus cf. P. platyrhinus, is described from lowermost Triassic Lystrosaurus Assemblage Zone strata in the main Karoo Basin of South Africa. The specimen preserves information previously unknown in the genus, including details of the posterior region of the skull and intertemporal region, and a partial (though disarticulated) postcranial skeleton. A cladistic analysis of 32 therapsid taxa, including 24 Permo-Triassic therocephalian genera, and 121 craniodental and postcranial characters supports the specimen's placement within the Permian akidnognathid genus Promoschorhynchus (making it the youngest documented occurrence of this taxon) within a monophyletic Therocephalia. Inclusion of new postcranial characters strengthens support of the therocephalian clade. The new record of Promoschorhynchus offers insights into the diversity of eutheriodonts across the Permo-Triassic boundary (PTB) in the Karoo Basin. In contrast to cynodonts, therocephalians exhibited decreased rates of cladogenesis across the PTB, with several Triassic lineages having roots in the Late Permian rather than representing earliest Triassic radiations.
Smilosuchus in Color
What makes Jeff Martz's Smilisuchus (Phytosauridae) reconstruction even better? A bit of color.
Archeopelta arborensis a New Doswellidid Archosauriform from the Triassic of Brazil
Desojo, J. B., Ezcurra, M. D., and C. L. Schultz. 2011. An unusual new archosauriform from the Middle–Late Triassic of southern Brazil and the monophyly of Doswelliidae. Zoological Journal of the Linnean Society, 2011, 161, 839–871. DOI: 10.1111/j.1096-3642.2010.00655.x
Abstract - Until now the Doswelliidae was considered a monospecific family including Doswellia kaltenbachi from the Late Triassic of North America. The phylogenetic position of this taxon remained enigmatic until recently, when a sister-group relationship with the Proterochampsidae was suggested. In the present contribution we describe the new doswelliid species Archeopelta arborensis gen. et sp. nov. from the Middle–Late Triassic of Brazil. A cladistic analysis recovered Archeopelta, Doswellia, and Tarjadia within a monophyletic group of basal archosauriforms, the Doswelliidae. The monophyly of this family is supported by the presence of osteoderm ornamentation that is coarse, incised, and composed of regular pits and the presence of an unornamented anterior articular lamina. Archeopelta is more closely related to Doswellia than to other archosauriforms by the presence of basipterygoid processes anterolaterally orientated, dorsal centra with a convex surface, width of the neural arch plus ribs of the first primordial sacral that are three times the length of the neural arch, and iliac blade laterally deflected, with strongly convex dorsal margin, and a length less than three times its height. The phylogenetic analysis indicates that Doswellidae is the closest large monophyletic entity to Archosauria, which achieved a wide palaeolatitudinal distribution during the late Middle and Late Triassic time span.
Abstract - Until now the Doswelliidae was considered a monospecific family including Doswellia kaltenbachi from the Late Triassic of North America. The phylogenetic position of this taxon remained enigmatic until recently, when a sister-group relationship with the Proterochampsidae was suggested. In the present contribution we describe the new doswelliid species Archeopelta arborensis gen. et sp. nov. from the Middle–Late Triassic of Brazil. A cladistic analysis recovered Archeopelta, Doswellia, and Tarjadia within a monophyletic group of basal archosauriforms, the Doswelliidae. The monophyly of this family is supported by the presence of osteoderm ornamentation that is coarse, incised, and composed of regular pits and the presence of an unornamented anterior articular lamina. Archeopelta is more closely related to Doswellia than to other archosauriforms by the presence of basipterygoid processes anterolaterally orientated, dorsal centra with a convex surface, width of the neural arch plus ribs of the first primordial sacral that are three times the length of the neural arch, and iliac blade laterally deflected, with strongly convex dorsal margin, and a length less than three times its height. The phylogenetic analysis indicates that Doswellidae is the closest large monophyletic entity to Archosauria, which achieved a wide palaeolatitudinal distribution during the late Middle and Late Triassic time span.
New Information of a Key Triassic Tritheledontid From Brazil
Another paper from the Proceedings of the Third Gondwanan Dinosaur Symposium
Soares, M. B., Schultz, C. L., and B. L. D. Horn. 2011. New information on Riograndia guaibensis Bonaparte, Ferigolo & Ribeiro, 2001 (Eucynodontia, Tritheledontidae) from the Late Triassic of southern Brazil: anatomical and biostratigraphic implications. Anais da Academia Brasileira de Ciências 83:329-354.
Abstract - The tritheledontid Riograndia guaibensis was the first cynodont described for the “Caturrita Formation” fauna from the Late Triassic of southern Brazil (Santa Maria 2 Sequence). The type materials did not preserve anatomical information regarding braincase, occiput, basicranium, zygomatic arch, postdentary bones and craniomandibular joint. Here new materials are described and supply the missing information. Riograndia shows a suite of important anatomical features quite derived among the non-mammaliaform eucynodonts, such as the partial closure of the medial orbital wall and braincase, extensive secondary osseous palate, wide primary palate, basicranium with jugular foramen separated from the periphery of fenestra rotunda, narrow zygomatic arch and much reduced postdentary bones. Many of these features constitute synapomorphies shared only with the other members of mammaliamorpha. Thus, the almost complete cranial, mandibular and dental information from the new fossils of Riograndia can bring a significant improve in the understanding of the anatomy and phylogenetic relationships of the tritheledontids and help to elucidate the transformational steps involved in the cynodont-mammal transition. Additionally, Riograndia is a key taxon in refining the “Caturrita Formation” biostratigraphy, enabling the connection of several fossiliferous outcrops that have a rich tetrapod fauna that can be correlated with other Triassic faunas from Gondwana and Laurasia.
Soares, M. B., Schultz, C. L., and B. L. D. Horn. 2011. New information on Riograndia guaibensis Bonaparte, Ferigolo & Ribeiro, 2001 (Eucynodontia, Tritheledontidae) from the Late Triassic of southern Brazil: anatomical and biostratigraphic implications. Anais da Academia Brasileira de Ciências 83:329-354.
Abstract - The tritheledontid Riograndia guaibensis was the first cynodont described for the “Caturrita Formation” fauna from the Late Triassic of southern Brazil (Santa Maria 2 Sequence). The type materials did not preserve anatomical information regarding braincase, occiput, basicranium, zygomatic arch, postdentary bones and craniomandibular joint. Here new materials are described and supply the missing information. Riograndia shows a suite of important anatomical features quite derived among the non-mammaliaform eucynodonts, such as the partial closure of the medial orbital wall and braincase, extensive secondary osseous palate, wide primary palate, basicranium with jugular foramen separated from the periphery of fenestra rotunda, narrow zygomatic arch and much reduced postdentary bones. Many of these features constitute synapomorphies shared only with the other members of mammaliamorpha. Thus, the almost complete cranial, mandibular and dental information from the new fossils of Riograndia can bring a significant improve in the understanding of the anatomy and phylogenetic relationships of the tritheledontids and help to elucidate the transformational steps involved in the cynodont-mammal transition. Additionally, Riograndia is a key taxon in refining the “Caturrita Formation” biostratigraphy, enabling the connection of several fossiliferous outcrops that have a rich tetrapod fauna that can be correlated with other Triassic faunas from Gondwana and Laurasia.
New Triassic Dinosaur Papers from the Proceedings of the Third Gondwanan Dinosaur Symposium
Most of you are probably aware that the Proceedings of the Third Gondwanan Dinosaur Symposium have just been published in the journal Anais da Academia Brasileira de Ciências. There are numerous papers here, three of which pertain to the Triassic. You can view and download all of the papers from the following link:
http://www.scielo.br/scielo.php?script=sci_issuetoc&pid=0001-376520110001&ln
I have listed the relevent Triassic dinosaur papers below.
Bittencourt, J. S., and M. C. Langer. 2011. Mesozoic dinosaurs from Brazil and their biogeographic implications. Anais da Academia Brasileira de Ciências 83:23-60.
Abstract - The record of dinosaur body-fossils in the Brazilian Mesozoic is restricted to the Triassic of Rio Grande do Sul and Cretaceous of various parts of the country. This includes 21 named species, two of which were regarded as nomina dubia, and 19 consensually assigned to Dinosauria. Additional eight supraspecific taxa have been identified based on fragmentary specimens and numerous dinosaur footprints known in Brazil. In fact, most Brazilian specimens related to dinosaurs are composed of isolated teeth and vertebrae. Despite the increase of fieldwork during the last decade, there are still no dinosaur body-fossils of Jurassic age and the evidence of ornithischians in Brazil is very limited. Dinosaur faunas from this country are generally correlated with those from other parts of Gondwana throughout the Mesozoic. During the Late Triassic, there is a close correspondence to Argentina and other south-Pangaea areas. Mid-Cretaceous faunas of northeastern Brazil resemble those of coeval deposits of North Africa and Argentina. Southern hemisphere spinosaurids are restricted to Africa and Brazil, whereas abelisaurids are still unknown in the Early Cretaceous of the latter. Late Cretaceous dinosaur assemblages of south-central Brazil are endemic only to genus or, more conspicuously, to species level, sharing closely related taxa with Argentina, Madagascar, Indo-Pakistan and, to a lesser degree, continental Africa.
and two new papers on Staurikosaurus, one of which was previously mentioned here.
Grillo, O. N., and S. A. K. Azevedo. 2011. Pelvic and hind limb musculature of Staurikosaurus pricei (Dinosauria: Saurischia). Anais da Academia Brasileira de Ciências 83:73-98.
Abstract - The study of pelvic and hind limb bones and muscles in basal dinosaurs is important for understanding the early evolution of bipedal locomotion in the group. The use of data from both extant and extinct taxa placed into a phylogenetic context allowed to make well-supported inferences concerning most of the hind limb musculature of the basal saurischian Staurikosaurus pricei Colbert, 1970 (Santa Maria Formation, Late Triassic of Rio Grande do Sul, Brazil). Two large concavities in the lateral surface of the ilium represent the origin of the muscles iliotrochantericus caudalis plus iliofemoralis externus (in the anterior concavity) and iliofibularis (in the posterior concavity). Muscle ambiens has only one head and originates from the pubic tubercle. The origin of puboischiofemoralis internus 1 possibly corresponds to a fossa in the ventral margin of the preacetabular iliac process. This could represent an intermediate stage prior to the origin of a true preacetabular fossa. Muscles caudofemorales longus et brevis were likely well developed, and Staurikosaurus is unique in bearing a posteriorly projected surface for the origin of caudofemoralis brevis.
http://www.scielo.br/scielo.php?script=sci_issuetoc&pid=0001-376520110001&ln
I have listed the relevent Triassic dinosaur papers below.
Bittencourt, J. S., and M. C. Langer. 2011. Mesozoic dinosaurs from Brazil and their biogeographic implications. Anais da Academia Brasileira de Ciências 83:23-60.
Abstract - The record of dinosaur body-fossils in the Brazilian Mesozoic is restricted to the Triassic of Rio Grande do Sul and Cretaceous of various parts of the country. This includes 21 named species, two of which were regarded as nomina dubia, and 19 consensually assigned to Dinosauria. Additional eight supraspecific taxa have been identified based on fragmentary specimens and numerous dinosaur footprints known in Brazil. In fact, most Brazilian specimens related to dinosaurs are composed of isolated teeth and vertebrae. Despite the increase of fieldwork during the last decade, there are still no dinosaur body-fossils of Jurassic age and the evidence of ornithischians in Brazil is very limited. Dinosaur faunas from this country are generally correlated with those from other parts of Gondwana throughout the Mesozoic. During the Late Triassic, there is a close correspondence to Argentina and other south-Pangaea areas. Mid-Cretaceous faunas of northeastern Brazil resemble those of coeval deposits of North Africa and Argentina. Southern hemisphere spinosaurids are restricted to Africa and Brazil, whereas abelisaurids are still unknown in the Early Cretaceous of the latter. Late Cretaceous dinosaur assemblages of south-central Brazil are endemic only to genus or, more conspicuously, to species level, sharing closely related taxa with Argentina, Madagascar, Indo-Pakistan and, to a lesser degree, continental Africa.
and two new papers on Staurikosaurus, one of which was previously mentioned here.
Grillo, O. N., and S. A. K. Azevedo. 2011. Pelvic and hind limb musculature of Staurikosaurus pricei (Dinosauria: Saurischia). Anais da Academia Brasileira de Ciências 83:73-98.
Abstract - The study of pelvic and hind limb bones and muscles in basal dinosaurs is important for understanding the early evolution of bipedal locomotion in the group. The use of data from both extant and extinct taxa placed into a phylogenetic context allowed to make well-supported inferences concerning most of the hind limb musculature of the basal saurischian Staurikosaurus pricei Colbert, 1970 (Santa Maria Formation, Late Triassic of Rio Grande do Sul, Brazil). Two large concavities in the lateral surface of the ilium represent the origin of the muscles iliotrochantericus caudalis plus iliofemoralis externus (in the anterior concavity) and iliofibularis (in the posterior concavity). Muscle ambiens has only one head and originates from the pubic tubercle. The origin of puboischiofemoralis internus 1 possibly corresponds to a fossa in the ventral margin of the preacetabular iliac process. This could represent an intermediate stage prior to the origin of a true preacetabular fossa. Muscles caudofemorales longus et brevis were likely well developed, and Staurikosaurus is unique in bearing a posteriorly projected surface for the origin of caudofemoralis brevis.
Atmospheric CO2 Effects of the Central Atlantic Magmatic Province Eruptions
Schaller, M. F., Wright, J. D., and D. V. Kent. 2011. Atmospheric PCO2 Perturbations Associated with the Central Atlantic Magmatic Province. Science 331: 1404-1409. DOI: 10.1126/science.1199011
Abstract - The effects of a large igneous province on the concentration of atmospheric carbon dioxide (PCO2) are mostly unknown. In this study, we estimate PCO2 from stable isotopic values of pedogenic carbonates interbedded with volcanics of the Central Atlantic Magmatic Province (CAMP) in the Newark Basin, eastern North America. We find pre-CAMP PCO2 values of ~2000 parts per million (ppm), increasing to ~4400 ppm immediately after the first volcanic unit, followed by a steady decrease toward pre-eruptive levels over the subsequent 300 thousand years, a pattern that is repeated after the second and third flow units. We interpret each PCO2 increase as a direct response to magmatic activity (primary outgassing or contact metamorphism). The systematic decreases in PCO2 after each magmatic episode probably reflect consumption of atmospheric CO2 by weathering of silicates, stimulated by fresh CAMP volcanics.
Abstract - The effects of a large igneous province on the concentration of atmospheric carbon dioxide (PCO2) are mostly unknown. In this study, we estimate PCO2 from stable isotopic values of pedogenic carbonates interbedded with volcanics of the Central Atlantic Magmatic Province (CAMP) in the Newark Basin, eastern North America. We find pre-CAMP PCO2 values of ~2000 parts per million (ppm), increasing to ~4400 ppm immediately after the first volcanic unit, followed by a steady decrease toward pre-eruptive levels over the subsequent 300 thousand years, a pattern that is repeated after the second and third flow units. We interpret each PCO2 increase as a direct response to magmatic activity (primary outgassing or contact metamorphism). The systematic decreases in PCO2 after each magmatic episode probably reflect consumption of atmospheric CO2 by weathering of silicates, stimulated by fresh CAMP volcanics.
The Petrified Forest Model T: Evidence for Bootleggers in the Painted Desert?
One of the hiking goals of employees and visitors at the Petrified Forest is to make it out to the Model T in the northern Painted Desert Wilderness area. Although it is only about 4 miles out 'as a crow flies', manupulating through the washes and badlands adds a good amount of distance to your trip, so that the total round trip is more like 10 miles with no shade. Plus you have a good trek up a 100+ foot mesa at the very end of your trip.
I've attached a couple of pictures of the "goal" below. The question we always wonder is how did this vehicle get out here in the middle of nowhere? The main story is that the car actually belonged to bootleggers who were transporting alcohol illegally to the nearby Navajo Reservation. There vehicle was stuck in a small wash and mud and abandoned. It is in pretty good shape still. You can sit in the drivers seat and steer and a park ritual is to have your photo taken driving the Model T. A few years back we recorded the serial numbers from the engine block and sent them to Ford in an attempt to track down any ownership records, but to no avail.
One of the cool things about the Petrified Forest is its long history (established in 1906) and all of the hidden 'gems' scattered throughout the park for the more adventurous to find.
I've attached a couple of pictures of the "goal" below. The question we always wonder is how did this vehicle get out here in the middle of nowhere? The main story is that the car actually belonged to bootleggers who were transporting alcohol illegally to the nearby Navajo Reservation. There vehicle was stuck in a small wash and mud and abandoned. It is in pretty good shape still. You can sit in the drivers seat and steer and a park ritual is to have your photo taken driving the Model T. A few years back we recorded the serial numbers from the engine block and sent them to Ford in an attempt to track down any ownership records, but to no avail.
New Information from CT Scans on the Braincase of a Middle Triassic Shark
Maisey, J. G. 2011. The braincase of the Middle Triassic shark Acronemus tuberculatus (Bassani, 1886). Palaeontology 54:417-428. DOI: 10.1111/j.1475-4983.2011.01035.x
Abstract - The chondrocranium of the enigmatic Middle Triassic shark Acronemus tuberculatus is investigated using computerized tomography scanning and 3-D digital reconstitution techniques. The braincase reveals some autapomorphies, plus other features that suggest a phylogenetic relationship to both hybodontiform and neoselachian elasmobranchs, including evidence of features implicated in low-frequency semi-directional phonoreception. Acronemus can no longer be classified as a ‘ctenacanthiform’, although its relationships remain elusive and it presents supposedly hybodontiform and neoselachian features that have not previously been found in combination.
Abstract - The chondrocranium of the enigmatic Middle Triassic shark Acronemus tuberculatus is investigated using computerized tomography scanning and 3-D digital reconstitution techniques. The braincase reveals some autapomorphies, plus other features that suggest a phylogenetic relationship to both hybodontiform and neoselachian elasmobranchs, including evidence of features implicated in low-frequency semi-directional phonoreception. Acronemus can no longer be classified as a ‘ctenacanthiform’, although its relationships remain elusive and it presents supposedly hybodontiform and neoselachian features that have not previously been found in combination.
"Old Paleontologists Never Die. Their Knees Just Give Out"
This is an excellent account of the joys and importance of field paleontology (and some of the luck involved) in an interview with one of the 'greats' in the field of vertebrate paleontology, Dr. Mary Dawson of the Carnegie Museum.
http://www.post-gazette.com/pg/11072/1131175-51.stm
This article also mentions why it is important to revisit your previous digs and look for the pieces you are missing, many times they are often turned up by further erosion. In 2006 Randall Irmis and I described a new species of phytosaur, Pseudopalatus jablonskiae. One of the crucial preserved portions of the specimen was its braincase, which is one of the best preserved Pseudopalatus braincases ever found and in this particular species gives clues of the phylogenetic relationships between Pseudopalatus and the earlier Smilosuchus. Unfortunately, the specimen had been trampled and slowly kicked apart (it was located on a trail). Many of the fragments had been washed downslope and reburied. We were able to piece together the braincase but lacked the lower portion, the basicranium.
In 2008 I revisited the site and found more fragments that had eroded out from the downslope area and one of these was the nearly complete basicranium! At some point I will have to prepare a redescription of the entire braincase of this very cool (and important) specimen,
http://www.post-gazette.com/pg/11072/1131175-51.stm
This article also mentions why it is important to revisit your previous digs and look for the pieces you are missing, many times they are often turned up by further erosion. In 2006 Randall Irmis and I described a new species of phytosaur, Pseudopalatus jablonskiae. One of the crucial preserved portions of the specimen was its braincase, which is one of the best preserved Pseudopalatus braincases ever found and in this particular species gives clues of the phylogenetic relationships between Pseudopalatus and the earlier Smilosuchus. Unfortunately, the specimen had been trampled and slowly kicked apart (it was located on a trail). Many of the fragments had been washed downslope and reburied. We were able to piece together the braincase but lacked the lower portion, the basicranium.
In 2008 I revisited the site and found more fragments that had eroded out from the downslope area and one of these was the nearly complete basicranium! At some point I will have to prepare a redescription of the entire braincase of this very cool (and important) specimen,
Paleontology Blogroll Updates
I try to keep my blogroll current and up-to-date with the best paleontology blogs. Part of this is because I realize this is how I get a lot of my traffic. I've gotten many positive comments and am glad that many of my readers find it to be a useful resource.
If anyone wants to suggest he inclusion of any good paleontology-themed blogs that I don't have listed please let me know as a comment below. One exception is Brian Switek's excellent blog, Laelaps. It is not linked because there does not appear to be any way to directly link his site at Wired. If anyone has figured out how to do this please let me know.
Finally, I usually delete blog links if the authors have not posted anything new for more than six months. I still have Dr. Vector linked even though Matt Wedel doesn't really post there anymore. Maybe he is finally completely finished with that site? I would also appreciate it if Matt Celeskey would let me know if the Hairy Museum of Natural History site is defunct, or maybe my link is outdated?
If anyone wants to suggest he inclusion of any good paleontology-themed blogs that I don't have listed please let me know as a comment below. One exception is Brian Switek's excellent blog, Laelaps. It is not linked because there does not appear to be any way to directly link his site at Wired. If anyone has figured out how to do this please let me know.
Finally, I usually delete blog links if the authors have not posted anything new for more than six months. I still have Dr. Vector linked even though Matt Wedel doesn't really post there anymore. Maybe he is finally completely finished with that site? I would also appreciate it if Matt Celeskey would let me know if the Hairy Museum of Natural History site is defunct, or maybe my link is outdated?
Postcranial Skeletal Pneumaticity in Basal Sauropodomorphs
Yates, A. M., Wedel, M. J., and M. F. Bonnan. 2011. The early evolution of postcranial skeletal pneumaticity in sauropodomorph dinosaurs. Acta Palaeontologica Polonica in press available online 07 Mar 2011 doi:10.4202/app.2010.0075
Abstract - Postcranial skeletal pneumaticity (PSP) is present in a range of basal sauropodomorphs spanning the basal sauropodomorph–sauropod transition. We describe the PSP of five taxa, Plateosaurus engelhardti, Eucnemesaurus fortis, Aardonyx celestae, Antetonitrus ingenipes and an unnamed basal sauropod from Spion Kop, South Africa (hereafter referred to as the Spion Kop sauropod). The PSP of Plateosaurus is apparently sporadic in its occurrence and has only been observed in very few specimens, in which it is of very limited extent, affecting only the posterior cervical vertebrae and possibly the mid dorsals in one specimen. The PSP of Eucnemesaurus, Aardonyx, Antetonitrus and the Spion Kop sauropod consists of subfossae (fossa-within-fossa structures) that excavate the vertices of the posterior infradiapophyseal fossae of the posterior dorsal vertebrae. These subfossae range from simple shallow depressions (Eucnemesaurus) to deep, steep-sided, internally subdivided and asymmetrically developed chambers (Antetonitrus). The middle and anterior dorsal vertebrae of these taxa lack PSP, demonstrating that abdominal air sacs were the source of the invasive diverticula. The presence of pneumatic features within the infradiapophyseal fossae suggest that the homologous fossae of more basal saurischians and dinosauriforms were receptacles that housed pneumatic diverticula. We suggest that it is probable that rigid non-compliant lungs ventilated by compliant posterior air sacs evolved prior to the origination of Dinosauria.
Abstract - Postcranial skeletal pneumaticity (PSP) is present in a range of basal sauropodomorphs spanning the basal sauropodomorph–sauropod transition. We describe the PSP of five taxa, Plateosaurus engelhardti, Eucnemesaurus fortis, Aardonyx celestae, Antetonitrus ingenipes and an unnamed basal sauropod from Spion Kop, South Africa (hereafter referred to as the Spion Kop sauropod). The PSP of Plateosaurus is apparently sporadic in its occurrence and has only been observed in very few specimens, in which it is of very limited extent, affecting only the posterior cervical vertebrae and possibly the mid dorsals in one specimen. The PSP of Eucnemesaurus, Aardonyx, Antetonitrus and the Spion Kop sauropod consists of subfossae (fossa-within-fossa structures) that excavate the vertices of the posterior infradiapophyseal fossae of the posterior dorsal vertebrae. These subfossae range from simple shallow depressions (Eucnemesaurus) to deep, steep-sided, internally subdivided and asymmetrically developed chambers (Antetonitrus). The middle and anterior dorsal vertebrae of these taxa lack PSP, demonstrating that abdominal air sacs were the source of the invasive diverticula. The presence of pneumatic features within the infradiapophyseal fossae suggest that the homologous fossae of more basal saurischians and dinosauriforms were receptacles that housed pneumatic diverticula. We suggest that it is probable that rigid non-compliant lungs ventilated by compliant posterior air sacs evolved prior to the origination of Dinosauria.
Neotype Designation for the Early Jurassic Sauropodomorph Massospondylus carinatus
Adam Yates has a new post over at his blog Dracovenator, regarding the status of the type specimen of Massospondylus carinatus, and mentions this new paper that provides a neotype designation for this taxon. Unfortunately the Palaeontologia Africana website is woefully out of date and therefore I cannot provide an abstract or a link to this article.
Yates, A. M. and Barrett, P. M. 2011 (for 2010). Massospondylus carinatus Owen 1854 (Dinosauria, Sauropodomorpha): proposed conservation of usage by designation of a neotype. Palaeontologia Africana 45: 7-10.
Yates, A. M. and Barrett, P. M. 2011 (for 2010). Massospondylus carinatus Owen 1854 (Dinosauria, Sauropodomorpha): proposed conservation of usage by designation of a neotype. Palaeontologia Africana 45: 7-10.
Anatomy of the Basal Sauropodomorph Pantydraco caducus from the Upper Triassic of the UK
Just received this.....
Galton, P. M., and D. Kermack. 2010. The anatomy of Pantydraco caducus, a very basal sauropodomorph dinosaur from the Rhaetian (Upper Triassic) of South Wales, UK. Revue de Paléobiologie, Genève 29 (2) : 341-404.
Abstract - Apart from characters of the dentary (proportional shortness, also Saturnalia tupiniquim) and vertebrae of proximal third of tail (posterior position of antero-posteriorly short neural spine on arch, absence of ventral furrowing on centra ; both also Efraasia minor), the bones of very basal sauropodomorphs from the Rhaetian (Upper Triassic) fissure fill in Clifton near Bristol (including holotypes of Thecodontosaurus antiquus, Asylosaurus yalensis ; taxon with robust humerus) share no diagnostic characters with those of Pantydraco caducus from the Rhaetian of South Wales. This taxon is diagnosed by four autapomorphies : median fusion of the nasals, prominent medial tubercle from posterior part of surangular, epipophyses of cervical vertebrae 3-5 form flat plates that overhang the posterior margins of the postzygapophyseal facets but do not form raised ridges on the dorsal surface of the postzygapophysis, and the fossae, possibly pneumatic, prominent on the neurocentral suture of cervical vertebrae 6-8 and shallow on the lateral part of centrum 9. The dentary is deep and short, with maximum height of more than 20 % of length (also Saturnalia tupiniquim, Thecodontosaurus antiquus), occupying less than 40 % of total mandibular length (also Saturnalia tupiniquim). The ilium is tall with a long anterior process (also Anchisaurus polyzelus) and a short postacetabular process with the plesiomorphic absence of a brevis shelf. Other plesiomorphic characters include the lack of a buccal emargination on the dentary (also Saturnalia tupiniquim); teeth all recurved in lateral view; neck short with mid-cervical centra less than three times as long as wide (also Riojasaurus incertus, “Gyposaurus” sinensis) ; and humerus with a uniquely small tubercle medial to head and an antero-posteriorly low (also Asylosaurus yalensis) asymmetrical deltopectoral crest with the apex at 40 % of humeral length. At least three different sized individuals are preserved and the new skeletal reconstruction, with the posterior region scaled up to match the larger holotype, indicates a more bipedal animal than the more quadrupedal pose based on the incorrect premise that the two main blocks represent one individual. The specimens represent juveniles as indicated by the proportionally large skull with large orbits and short, high snout, slender postorbital bone, separation of most of bones of braincase, large metotic fissure and fenestra ovalis, low maxillary and dentary tooth counts, open neurocentral sutures of cervical vertebrae, and incomplete ossification of distal ends of the femur and metatarsals. The diversity of basal sauropodomorphs from the Rhaetian of Wales and England adjacent to the Severn Estuary is high with five taxa (Pantydraco caducus, three from Clifton, large basal sauropod Camelotia borealis from Somerset).
Galton, P. M., and D. Kermack. 2010. The anatomy of Pantydraco caducus, a very basal sauropodomorph dinosaur from the Rhaetian (Upper Triassic) of South Wales, UK. Revue de Paléobiologie, Genève 29 (2) : 341-404.
Abstract - Apart from characters of the dentary (proportional shortness, also Saturnalia tupiniquim) and vertebrae of proximal third of tail (posterior position of antero-posteriorly short neural spine on arch, absence of ventral furrowing on centra ; both also Efraasia minor), the bones of very basal sauropodomorphs from the Rhaetian (Upper Triassic) fissure fill in Clifton near Bristol (including holotypes of Thecodontosaurus antiquus, Asylosaurus yalensis ; taxon with robust humerus) share no diagnostic characters with those of Pantydraco caducus from the Rhaetian of South Wales. This taxon is diagnosed by four autapomorphies : median fusion of the nasals, prominent medial tubercle from posterior part of surangular, epipophyses of cervical vertebrae 3-5 form flat plates that overhang the posterior margins of the postzygapophyseal facets but do not form raised ridges on the dorsal surface of the postzygapophysis, and the fossae, possibly pneumatic, prominent on the neurocentral suture of cervical vertebrae 6-8 and shallow on the lateral part of centrum 9. The dentary is deep and short, with maximum height of more than 20 % of length (also Saturnalia tupiniquim, Thecodontosaurus antiquus), occupying less than 40 % of total mandibular length (also Saturnalia tupiniquim). The ilium is tall with a long anterior process (also Anchisaurus polyzelus) and a short postacetabular process with the plesiomorphic absence of a brevis shelf. Other plesiomorphic characters include the lack of a buccal emargination on the dentary (also Saturnalia tupiniquim); teeth all recurved in lateral view; neck short with mid-cervical centra less than three times as long as wide (also Riojasaurus incertus, “Gyposaurus” sinensis) ; and humerus with a uniquely small tubercle medial to head and an antero-posteriorly low (also Asylosaurus yalensis) asymmetrical deltopectoral crest with the apex at 40 % of humeral length. At least three different sized individuals are preserved and the new skeletal reconstruction, with the posterior region scaled up to match the larger holotype, indicates a more bipedal animal than the more quadrupedal pose based on the incorrect premise that the two main blocks represent one individual. The specimens represent juveniles as indicated by the proportionally large skull with large orbits and short, high snout, slender postorbital bone, separation of most of bones of braincase, large metotic fissure and fenestra ovalis, low maxillary and dentary tooth counts, open neurocentral sutures of cervical vertebrae, and incomplete ossification of distal ends of the femur and metatarsals. The diversity of basal sauropodomorphs from the Rhaetian of Wales and England adjacent to the Severn Estuary is high with five taxa (Pantydraco caducus, three from Clifton, large basal sauropod Camelotia borealis from Somerset).
New Tanystropheids from the Early Triassic of Europe
I don't have access to this article, only the abstract.
Sennikov, A.G. 2011. New Tanystropheids (Reptilia: Archosauromorpha) from the Triassic of Europe. Palaeontological Journal 45:95-104. DOI: 10.1134/S0031030111010151
Abstract—A new prolacertilian species and genus, Augustaburiania vatagini gen. et sp. nov. (Reptilia: Archosauromorpha), from the Lower Triassic of the Don River Basin is described. It is the first representative of the Tanystropheidae in the Eastern Europe and the world oldest member of this family. Another new genus (Protanystropheus gen. nov.) from Central and Western Europe is also established. The diversity, systematics, phylogeny, evolution, and stratigraphic and geographical distribution of prolacertilians are discussed. The ecological role of prolacertilians in Early Triassic communities and adaptation to marine environments are analyzed.
Sennikov, A.G. 2011. New Tanystropheids (Reptilia: Archosauromorpha) from the Triassic of Europe. Palaeontological Journal 45:95-104. DOI: 10.1134/S0031030111010151
Abstract—A new prolacertilian species and genus, Augustaburiania vatagini gen. et sp. nov. (Reptilia: Archosauromorpha), from the Lower Triassic of the Don River Basin is described. It is the first representative of the Tanystropheidae in the Eastern Europe and the world oldest member of this family. Another new genus (Protanystropheus gen. nov.) from Central and Western Europe is also established. The diversity, systematics, phylogeny, evolution, and stratigraphic and geographical distribution of prolacertilians are discussed. The ecological role of prolacertilians in Early Triassic communities and adaptation to marine environments are analyzed.
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