Snout Shape in Extant Ruminants

Copyright: © 2014 Tennant, MacLeod. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. [4.0 license]. The attached file is the published version of the article

Lower Miocene Stratigraphy along the Panama Canal and Its Bearing on the Central American Peninsula

Before the formation of the Central American Isthmus, there was a Central American Peninsula. Here we show that southern Central America existed as a peninsula as early as 19 Ma, based on new lithostratigraphic, biostratigraphic and strontium chemostratigraphic analyses of the formations exposed along the Gaillard Cut of the Panama Canal. Land mammals found in the Miocene Cucaracha Formation have similar body sizes to conspecific taxa in North America, indicating that there existed a terrestrial connection with North America that allowed gene flow between populations during this time. How long did this peninsula last? The answer hinges on the outcome of a stratigraphic dispute: To wit, is the terrestrial Cucaracha Formation older or younger than the marine La Boca Formation? Previous stratigraphic studies of the Panama Canal Basin have suggested that the Cucaracha Formation lies stratigraphically between the shallow-marine Culebra Formation and the shallow-to-upper-bathyal La Boca Formation, the latter containing the Emperador Limestone. If the La Boca Formation is younger than the Cucaracha Formation, as many think, then the peninsula was short-lived (1–2 m.y.), having been submerged in part by the transgression represented by the overlying La Boca Formation. On the other hand, our data support the view that the La Boca Formation is older than the Cucaracha Formation. Strontium dating shows that the La Boca Formation is older (23.07 to 20.62 Ma) than both the Culebra (19.83–19.12 Ma) and Cucaracha (Hemingfordian to Barstovian North American Land Mammal Ages; 19–14 Ma) formations. The Emperador Limestone is also older (21.24–20.99 Ma) than the Culebra and Cucaracha formations. What has been called the “La Boca Formation” (with the Emperador Limestone), is re-interpreted here as being the lower part of the Culebra Formation. Our new data sets demonstrate that the main axis of the volcanic arc in southern Central America more than likely existed as a peninsula connected to northern Central America and North America for much of the Miocene, which has profound implications for our understanding of the tectonic, climatic, oceanographic and biogeographic history related to the formation of the Isthmus of Panama

The Palaeontology of Browsing and Grazing

Peer reviewe

Achado de bactérias selecionadas em crianças de Trinidad com doença amigdaliana crônica Selected bacterial recovery in Trinidadian children with chronic tonsillar disease

Faringoamigdalite na população pediátrica é largamente tratada com antibióticos. OBJETIVO: Estudar a microflora presente na superfície e no núcleo de amígdalas após adenoamigdalectomia eletiva em crianças. MÉTODO: Amígdalas de 102 crianças de Trinidad foram prospectivamente estudadas por meio de culturas e identificações bacteriológicas feitas a partir de amostras das superfícies e núcleos de suas amígdalas entre 2005-2006. RESULTADOS: A partir de 360 amígdalas, foram isolados Streptococcus spp. (51,3%), Staphylococcus spp. (42,3%) e Gram-Negativos (6,4%). A identificação de estafilococos e estreptococos tanto na superfície quanto no núcleo foi semelhante (p>0,05). Encontramos mais (p<0,001) Streptococcus spp. nas superfícies (82,2%) do que nos núcleos (63,3%); a prevalência de estreptococos alfa-hemolíticos foi maior (p<0,001) do que aquela de estreptococos beta-hemolíticos nas superfícies (74,4% vs. 18,6%) do que nos núcleos (58,9% vs. 13,7%). Não houve concordância entre superfícies e núcleos com relação a estreptococos (p<0,0004) e estreptococos alfa-hemolíticos (p<0,007). Estreptococos beta-hemolíticos foram mais identificados (p<0,05) em crianças dentre 6-16 anos do que naquelas entre 1-5 anos de idade (31% e 23,8% vs 12,5% e 8%). A prevalência de S. pyogenes na superfície e no núcleo foi de (84,6% vs 70%) e (50,0% vs 25,0%) em crianças de maior faixa etária e crianças mais novas, respectivamente. Klebsiella spp. (6,6%, 2,2%), Proteus (4,4%, 4,4%) e Pseudomonas (4,4 %, 1,1%) cresceram nas superfícies e núcleos, respectivamente. CONCLUSÃO: As superfícies amigdalianas tinham mais estreptococos e estreptococos hemolíticos do que seus núcleos. Crianças mais velhas tiveram mais estreptococos beta-hemolíticos, e são altamente colonizadoras de S. pyogenes. Sugerimos estudos que investiguem os mecanismos de aderência estreptocócica em crianças de Trinidad.<br>Pharyngotonsillitis in children is widely treated with antibiotics. AIM: To examine tonsil surface and core microflora following elective adenotonsillectomy in children. METHODS: Tonsils of 102 Trinidadian children were prospectively examined for surface and core bacteriological culture and identification between 2005-2006. RESULTS: Tonsils (360) yielded 800 isolates of Streptococcus spp. (51.3%), Staphylococcus spp. (42.3%) and Gram-negative genera (6.4%). Surface and core recovery of staphylococci and streptococci were similar (p>0.05). More (p<0.001) surfaces (82.2%) than cores (63.3%) grew Streptococcus spp.; &#945;-haemolytic Streptococcus prevalence was higher (p<0.001) than ß-haemolytic Streptococcus on surfaces (74.4% vs. 18.6%) than cores (58.9% vs. 13.7%). Surfaces and cores were not concordant for streptococci (p<0.0004) and &#945;-haemolytic Streptococcus (p<0.007). Surface and core ß-haemolytic Streptococcus yield was higher (p<0.05) in 6-16 than 1-5 year olds (31% and 23.8% vs 12.5% and 8%). S. pyogenes surface and core prevalence was (84.6% vs 70%) and (50.0% vs 25.0%) in older and younger children respectively. Klebsiella spp. (6.6 %, 2.2%), Proteus (4.4%, 4.4%) and Pseudomonas (4.4 %, 1.1%) grew on surfaces and cores respectively. CONCLUSION: Tonsil surfaces yield higher surface than core carriage for streptococci overall and for &#945; haemolytic streptococci. Older children grow more &#946;-haemolytic streptococci and are high colonizers of S. pyogenes. Studies probing the mechanisms of streptococcal adhesions in Trinidadian children are suggested