Publications in the Year: 2012

Journal Article

Myers, TS, Tabor NJ, Jacobs LL, Mateus O.  2012.  Estimating soil pCO2 using paleosol carbonates: implications for the relationship between primary productivity and faunal richness in ancient terrestrial ecosystems. Paleobiology. 38(4):585–604. Abstractmyers_et_al_2012_estimating_soil_paleosols_portugal.pdf

In this paper we present a method for estimating soil pCO2 in ancient environments using the measured carbon-isotope values of pedogenic carbonates and plant-derived organic matter. The validity of soil pCO2 estimates proves to be highly dependent on the organic δ13C values used in the calculations. Organic matter should be sourced from the same paleosol profiles as sampled carbonates to yield the most reliable estimates of soil pCO2. In order to demonstrate the potential use of soil pCO2 estimates in paleoecological and paleoenvironmental studies, we compare samples from three Upper Jurassic localities. Soil pCO2 estimates, interpreted as a qualitative indicator of primary paleoproductivity, are used to rank the Late Jurassic terrestrial environments represented by the Morrison Formation in western North America, the informally named Lourinhã formation in Western Europe, and the Stanleyville Group in Central Africa. Because modern terrestrial environments show a positive correlation between primary productivity and faunal richness, a similar relationship is expected in ancient ecosystems. When the relative paleoproductivity levels inferred for each study area are compared with estimates of dinosaur generic richness, a positive correlation emerges. Both the Morrison and Lourinhã formations have high inferred productivity levels and high estimated faunal richness. In contrast, the Stanleyville Group appears to have had low primary productivity and low faunal richness. Paleoclimatic data available for each study area indicate that both productivity and faunal richness are positively linked to water availability, as observed in modern terrestrial ecosystems.

Myers, TS, Tabor NJ, Jacobs LL, Mateus O.  2012.  Palaeoclimate of the late jurassic of portugal: Comparison with the western united states. Sedimentology. 59:1695-1717., Number 6 Abstract
Strganac, C, Ferguson, K.M, Jacobs JL, Polcyn MJ, Mateus O.  2012.  Age and paleoecology of mosasaurs and plesiosaurs from the Late Cretaceous South Atlantic margin at Bentiaba, Angola. Journal of Vertebrate Paleontology, Program and Abstracts, 2012. :180.strganac_et_al_mateus_2012_age_bentiaba_angola_2012_svp_abstract.pdf
Mannion, PD, Upchurch P, Mateus O, Barnes RN, Jones MEH.  2012.  New information on the anatomy and systematic position of Dinheirosaurus lourinhanensis (Sauropoda: Diplodocoidea) from the Late Jurassic of Portugal, with a review of European diplodocoids, Jan. Journal of Systematic Palaeontology. 10(3):521–551. Abstractmannion_et_al_2012_new_information_on_the_anatomy_and_systematic_position_of_dinheirosaurus_lourinhanensis_sauropoda_-_diplodocoidea_from_the_late_jurassic_of_portugal_with_a_review_of_european_diplodocoids.pdf

Although diplodocoid sauropods from Africa and the Americas are well known, their European record remains largely neglected. Here we redescribe Dinheirosaurus lourinhanensis from the Late Jurassic of Portugal. The holotype comprises two posterior cervical vertebrae, the dorsal series and a caudal centrum. Redescription demonstrates its validity on the basis of three autapomorphies: (1) posteriorly restricted ventral keel on posterior cervical vertebrae; (2) three small subcircular fossae posterior to the lateral coel on posterior cervical neural spines; (3) accessory lamina linking the hyposphene with base of the posterior centrodiapophyseal lamina in middle-posterior dorsal vertebrae. Phylogenetic analysis places Dinheirosaurus as the sister taxon to Supersaurus, and this clade forms the sister taxon to other diplodocines. However, this position should be treated with caution as Dinheirosaurus displays several plesiomorphic features absent in other diplodocids (including unbifurcated presacral neural spines, and dorsolaterally projecting diapophyses on dorsal vertebrae) and only four additional steps are required to place Dinheirosaurus outside of Flagellicaudata. We identify Amazonsaurus as the basal-most rebbachisaurid and recover Zapalasaurus outside of the South American Limaysaurinae, suggesting the biogeographic history of rebbachisaurids is more complex than previously proposed. Review of the European diplodocoid record reveals evidence for the earliest known diplodocid, as well as additional diplodocid remains from the Late Jurassic of Spain. A Portuguese specimen, previously referred to Dinheirosaurus, displays strong similarities to Apatosaurus from the contemporaneous Morrison Formation of North America, indicating the presence of a second Late Jurassic Portuguese diplodocid taxon. Along with Dinheirosaurus, these Portuguese remains provide further evidence for a Late Jurassic palaeobiogeographic connection between Europe and North America. No dicraeosaurids are currently known from Europe, but rebbachisaurids are present in the Early Cretaceous, with weak evidence for the earliest known representative from the Late Jurassic of Spain; however, more complete material is required to recognize early members of this clade.