PalArch » PalArch’s Journal of Vertebrate Palaeontology

Foster, J.R. 2013. Ecological Segregation of the Late Jurassic Stegosaurian and Iguanodontian Dinosaurs of the Morrison Formation in North America: Pronounced or Subtle? – PalArch’s Journal of Vertebrate Palaeontology 10(3) (2013), 1-11. ISSN 1567-2158. 11 pages + 4 figures, 1 table.

Palarch Editor (IJJN) — Wed, 22 May 2013 14:15:41 +0000

The Upper Jurassic Morrison Formation of western North America has yielded a number of specimens assigned to the ornithischian dinosaurs Stegosaurus and Camptosaurus, and many of these specimens come from channel sandstone deposits. Six new specimens are recorded mostly from channel sandstones as well. Indeed, early analyses of site occurrences (reducing the effects of large single-site samples) suggested that Stegosaurus and Camptosaurus were more often found in channel sandstone deposits than other common Morrison Formation dinosaurs such as Camarasaurus or Diplodocus. This also indicated the possibility of ecological segregation of the former two genera from other herbivorous dinosaurs of the Morrison. Revisiting this question with additional data suggests the pattern may not be as strong as it once appeared. Analysis of occurrence data indicates that Stegosaurus and Camptosaurus occur in channel sandstone deposits slightly more frequently than the two sauropods, but statistical analysis of this pattern by either localities or individuals indicates little significance to the trend. However, Camptosaurus appears more strongly associated with channel sandstone deposits relative to other dinosaurs than does Stegosaurus. These results suggest that any ecological segregation of these genera was moderate, but that, if present, the segregation was more pronounced in Camptosaurus.

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Farke, Andrew A. & Chiara A. Wilridge. 2013. A Possible Pterosaur Wing Phalanx from the Kaiparowits Formation (Late Campanian) of Southern Utah, USA – PalArch’s Journal of Vertebrate Palaeontology 10(2) (2013), 1-6. ISSN 1567-2158. 6 pages + 1 figure.

Palarch Editor (IJJN) — Sat, 20 Apr 2013 07:30:03 +0000

Abstract An isolated bone from the late Campanian-aged Kaiparowits Formation of southern Utah is tentatively identified as the terminal wing phalanx (manual phalanx IV-4) from a pterosaur, representing the first report of this clade from the formation. The specimen is 60 mm long and hollow, with thin and delicate walls and expanded ?proximal and ?distal ends. This is consistent with anatomy reported for equivalent elements in pterodactyloid pterosaurs. Although the specimen cannot be more precisely identified, it is consistent with occurrences of pterosaurs in penecontemporaneous terrestrial depositional environments throughout western North America.

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Wedel, M.J. & M.P. Taylor. 2013. Neural Spine Bifurcation in Sauropod Dinosaurs of the Morrison Formation: Ontogenetic and Phylogenetic Implications. – PalArch’s Journal of Vertebrate Palaeontology 10(1) (2013), 1-34. ISSN 1567-2158. 34 pages + 25 figures, 2 tables.

PalArch Editor (AV) — Fri, 15 Mar 2013 10:54:38 +0000

Abstract It has recently been argued that neural spine bifurcation increases through ontogeny in several Morrison Formation sauropods, that recognition of ontogenetic transformation in this ‘key character’ will have sweeping implications for sauropod phylogeny, and that Suuwassea and Haplocanthosaurus in particular are likely to be juveniles of known diplodocids. However, we find that serial variation in sauropod vertebrae can mimic ontogenetic change and is therefore a powerful confounding factor, especially when dealing with isolated elements whose serial position cannot be determined. When serial position is taken into account, there is no evidence that neural spine bifurcation increased over ontogeny in Morrison Formation diplodocids. Through phylogenetic analysis we show that neural spine bifurcation is not a key character in sauropod phylogeny and that Suuwassea and Haplocanthosaurus are almost certainly not juveniles of known diplodocids. Skeletochronology based on the sequence of skeletal fusions during ontogeny can provide relative ontogenetic ages for some sauropods. Although such data are sparsely available to date and often inconsistent among sauropod genera they provide another line of evidence for testing hypotheses of ontogenetic synonymy. Data from skeletal fusions suggest that Suuwassea and Haplocanthosaurus are both valid taxa and that neither is an ontogenetic morph of a known diplodocid.

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TER-QUA 2011 Proceedings: Steven E. Fields, H. Gregory McDonald, James L. Knight & Albert E. Sanders. 2012. The Ground Sloths (Pilosa) of South Carolina. – PalArch’s Journal of Vertebrate Palaeontology 9(3) (2012), 1-19. ISSN 1567-2158. 19 pages + 7 figures, 1 table.

PalArch Editor (AV) — Fri, 13 Apr 2012 08:23:09 +0000

Abstract A summary of museum and literature records of ground sloths collected from South Carolina is presented. The ground sloth record in South Carolina consists of three genera, Eremotheirum with two species, Megalonyx with three species and Paramylodon with one species. Three of these species, Eremotherium eomigrans and Megalonyx leptostomus from the Blancan and Megalonyx wheatleyi from the Irvingtonian are new records for the state. An early Pliocene specimen of M. leptostomus is the earliest record of sloths from South Carolina. The fossil record of sloths in the state extends from the Pliocene (Blancan) through the Pleistocene (Late Rancholabrean) and is confined to sedimentary deposits on the Coastal Plain.

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TER-QUA 2011 Proceedings: Robert M. Chandler. 2012. A New Species of Tinamou (Aves: Tinamiformes, Tinamidae) from the Early-Middle Miocene of Argentina. – PalArch’s Journal of Vertebrate Palaeontology 9(2) (2012), 1-8. ISSN 1567-2158. 8 pages + 2 figures, 1 table.

PalArch Editor (AV) — Tue, 10 Apr 2012 14:32:38 +0000

Abstract A new species of tinamou from the early-middle Miocene (Santacrusian), Santa Cruz Formation of Argentina is named. The new species is approximately 16 million year old and has an affinity with the modern genus Crypturellus based on the unique characteristics of the humerus, hence, the designation aff. Crypturellus. Fossil species and the zooarchaeological record of modern tinamous are given.

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TER-QUA 2011 Proceedings: Jeremy B. Stout. 2012. New Material of Borealosuchus from the Bridger Formation, with Notes on the Paleoecology of Wyoming’s Eocene Crocodylians. – PalArch’s Journal of Vertebrate Palaeontology 9(5) (2012), 1-7. ISSN 1567-2158. 7 pages + 3 figures, 1 table.

PalArch Editor (AV) — Thu, 05 Apr 2012 12:58:14 +0000

Abstract The Eocene Green River and Bridger Formations of Wyoming represent lacustrine and fluvial environments noteworthy for an extremely diverse crocodylian fauna (at least eight species in seven genera). This paper discusses a fragmentary crocodylian jaw from the Bridger Formation, and also notes possible ecological partitioning among these sympatric crocodylians. The jaw fragment can be assigned confi dently to Borealosuchus based on the exclusion of the splenial from the mandibular symphysis and the presence of occlusal grooves between the alveoli, and it is referred tentatively to Borealosuchus cf. B. wilsoni. To examine the paleoecology of these crocodylians, variables based on habitat, body size, and inferred diet were formulated and species placed within respective categories. The research found that while there were more sympatric crocodylians in the early to mid Eocene of Wyoming than in any present-day biota, direct interspecifi c competition for resources is presumed to have been relatively low.

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TER-QUA 2011 Proceedings: Pennilyn Higgins. 2012. Climate Change at the Paleocene-Eocene Boundary: New Insights from Mollusks and Organic Carbon in the Hanna Basin of Wyoming. – PalArch’s Journal of Vertebrate Palaeontology 9(4) (2012), 1-20. ISSN 1567-2158. 20 pages + 7 figures, 3 tables.

PalArch Editor (AV) — Thu, 05 Apr 2012 05:46:11 +0000

Abstract Climate change at the Paleocene-Eocene Thermal Maximum (PETM) is frequently regarded as among the best ancient proxies for the potential effects of modern climate change. Terrestrial sections recording this event are few, but essential in understanding the impacts of rapid global change on land-dwelling life forms such as humans. In the Hanna Formation, exposed in the Hanna Basin of south-central Wyoming, the PETM and associated climate change are recorded in lacustrine and fl uvial sediments bracketing the Paleocene-Eocene boundary. Isotopic analysis of abundant fossil mollusks and organic carbon reveal interesting trends in the warming during the PETM and the subsequent climatic recovery. Changes in sedimentary environment due to climate change or tectonic events may be distinguishable through isotopic study, helping to clarify the direct impact of climate change on terrestrial ecosystems.

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TER-QUA 2011 Proceedings: Larry D. Martin. 2012. Institute for Tertiary-Quarternary Studies (TER-QUA). – PalArch’s Journal of Vertebrate Palaeontology 9(1) (2012), 1-3. ISSN 1567-2158. 3 pages.

PalArch Editor (AV) — Thu, 05 Apr 2012 05:27:55 +0000

The start

TER-QUA (the Institute for Tertiary-Quaternary Studies) was organized in 1968 on the recommendation of the National Academy of Sciences/National Research Council’s U.S. National Committee of INQUA (the International Union for Quaternary Research). At this time it was under the directorships of Prof. Samuel Treves and Prof. Charles Bertrand Schultz both of the University of Nebraska. TER-QUA was formed to bring together [...]

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Rachel Zheng, Andrew A. Farke & Gy-Su Kim. 2011. A Photographic Atlas of the Pes from a Hadrosaurine Hadrosaurid Dinosaur. – PalArch’s Journal of Vertebrate Palaeontology 8(7) (2011), 1-12. ISSN 1567-2158. 12 pages + 7 fi gures, 2 tables.

Palarch Editor (IJJN) — Thu, 01 Dec 2011 10:27:09 +0000

Abstract Hadrosaurid dinosaurs are abundantly represented in terrestrial deposits from the Late Cretaceous, as isolated elements, associated specimens, and articulated skeletons with soft tissue. However, identifi cation of isolated elements can be diffi cult in the absence of adequate reference material. Here we present a photographic atlas of the complete pes from a hadrosaurine hadrosaurid (possibly Edmontosaurus annectens) collected in the Hell Creek Formation of Montana.

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Felipe Ribeiro de Santana, David J. Cicimurri & José Antonio Barbosa. 2011. New material of Apocopodon sericeus Cope, 1886 (Myliobatiformes, Myliobatidae) from the Paraíba Basin (Northeastern Brazil) and South Carolina (USA) with a reanalysis of the species.

Palarch Editor (IJJN) — Mon, 24 Oct 2011 06:37:02 +0000

Abstract Myliobatiformes (Elasmobranchii: Batoidei) is circumglobally distributed and consists of 26 extant genera within ten families. The oldest records of the group occur in upper Cretaceous deposits, and one extinct species, Apocopodon sericeus, is found in the Danian (lower Paleocene) Maria Farinha Formation of the Paraíba Basin, Pernambuco state, northeastern Brazil. This taxon is known from isolated teeth and several partial dentitions in various states of completeness, and herein we describe a new, incomplete (lingual portion) Brazilian dental plate. Previously considered to be endemic to the Paraíba Basin, Apocopodon was recently identifi ed from South Carolina, United States. The sample consists of a nearly complete upper(?) dentition and numerous isolated teeth, and the material is indistinguishable from A. sericeus. The precise stratigraphic position and age of the South Carolina fossils is unknown, but based on the other associated Paleocene vertebrate fossils, we believe that the fossils originated from the Danian Rhems Formation. The South Carolina occurrence of Apocopodon represents a signifi cant geographic range extension of more than 7,000 km to the north of the type area, and the occurrence of this ray in such widely separated areas demonstrates the dispersion potential of fossil elasmobranch species. Analysis of the new specimens, along with reanalysis of all previously known Apocopodon dentitions maintained in Brazilian institutions, resulted in a revision of the morphological characteristics used to identify the taxon.

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