First shark from the late Devonian (Frasnian) gogo formation, Western Australia sheds new light on the development of tessellated calcified cartilage

Background: Living gnathostomes (jawed vertebrates) comprise two divisions, Chondrichthyes (cartilaginous fishes, including euchondrichthyans with prismatic calcified cartilage, and extinct stem chondrichthyans) and Osteichthyes (bony fishes including tetrapods). Most of the early chondrichthyan (‘shark’) record is based upon isolated teeth, spines, and scales, with the oldest articulated sharks that exhibit major diagnostic characters of the group—prismatic calcified cartilage and pelvic claspers in males—being from the latest Devonian, c. 360 Mya. This paucity of information about early chondrichthyan anatomy is mainly due to their lack of endoskeletal bone and consequent low preservation potential. Methodology/Principal Findings: Here we present new data from the first well-preserved chondrichthyan fossil from the early Late Devonian (ca. 380–384 Mya) Gogo Formation Lägerstatte of Western Australia. The specimen is the first Devonian shark body fossil to be acid-prepared, revealing the endoskeletal elements as three-dimensional undistorted units: Meckel’s cartilages, nasal, ceratohyal, basibranchial and possible epibranchial cartilages, plus left and right scapulocoracoids, as well as teeth and scales. This unique specimen is assigned to Gogoselachus lynnbeazleyae n. gen. n. sp.Conclusions/Significance: The Meckel’s cartilages show a jaw articulation surface dominated by an expansive cotylus, and a small mandibular knob, an unusual condition for chondrichthyans. The scapulocoracoid of the new specimen shows evidence of two pectoral fin basal articulation facets, differing from the standard condition for early gnathostomes which have either one or three articulations. The tooth structure is intermediate between the ‘primitive’ ctenacanthiform and symmoriiform condition, and more derived forms with a euselachian-type base. Of special interest is the highly distinctive type of calcified cartilage forming the endoskeleton, comprising multiple layers of nonprismatic subpolygonal tesserae separated by a cellular matrix, interpreted as a transitional step toward the tessellated prismatic calcified cartilage that is recognized as the main diagnostic character of the chondrichthyans

Análise de incertezas físicas em simulação computacional de edificações residenciais

Resumo O objetivo deste trabalho é analisar incertezas físicas em simulação computacional de uma edificação residencial e sua implicação no desempenho térmico. O experimento foi elaborado com o método de Monte Carlo, que envolve as propriedades térmicas e físicas dos materiais da edificação. Foi analisada a sensibilidade das variáveis com coeficientes de regressão e correlação. Considerou-se o critério de graus-hora de desconforto por calor e por frio para o clima de Florianópolis, SC, conforme limites de conforto térmico adaptativo. Os resultados mostraram que as incertezas obtidas nos graus-hora são relativamente grandes, sendo de 32% no desconforto por frio e de 53% no desconforto por calor. Grande parte da incerteza é decorrente da temperatura média mensal do solo. Outras variáveis, como a absortância solar da cobertura e o calor específico da argamassa das paredes, resultam em impacto relevante no desconforto por calor, bem como a massa específica da argamassa e o calor específico da cerâmica das paredes no desconforto por frio. Essas variáveis precisam de maior precisão, seja por meio de bases de dados mais confiáveis, ou mesmo por medições em campo e/ou em laboratório

Affinities of Miocene Waterfowl (Anatidae: Manuherikia, Dunstanetta and Miotadorna) from the St Bathans Fauna, New Zealand

The recently described St Bathans Fauna, from the Manuherikia Group, Early-Middle Miocene, 19-16 Ma, New Zealand, includes six anatid taxa. Here we present detailed morphological descriptions of all available skeletal elements of the three best represented anatids: Manuherikia lacustrina (551 specimens), Dunstanetta johnstoneorum (7 specimens), and Miotadorna sanctibathansi (115 specimens). The affinities of these taxa, and of the similar-aged European taxon Mionetta blanchardi, are evaluated with phylogenetic analyses using a dataset of 133 characters (128 osteological, 5 integumental) and 57 terminal taxa. Representatives of all main anatid groups were included, with dense sampling of Australasian taxa including the recently extinct New Zealand forms (Cnemiornis, Chenonetta finschi), and relatively primitive taxa (anserines, Dendrocygna, oxyurines, tadornines). Analyses were conducted with no constraints, and with certain taxa constrained to conform to arrangements supported by multiple independent genetic studies. In the preferred (constrained) analyses: (1) anserines were the most basal anatids; (2) the four Tertiary fossil taxa were more derived than anserines and Dendrocygna; and (3) the European Mionetta blanchardi was basal to an oxyurine clade. The New Zealand fossils Manuherikia and Dunstanetta either associated with this oxyurine clade or formed separate lineages of an approximately oxyurine evolutionary grade, depending on whether diving characters were included or excluded. Similarly, Biziura, Thalassornis, and a Stictonetta - Malacorhynchus clade either associated with oxyurines or formed independent lineages of approximately oxyurine grade. Above oxyurines, a well-supported clade groups Miotadorna with Tadorna species exclusive of T. radjah. These results cast doubt on the distinctiveness of Dendrocheninae Livezey and Martin, 1988, and instead suggest oxyurine affinities for the Miocene fossils Mionetta, Dendrochen, Manuherikia and Dunstanetta, and the modern Biziura, Thalassornis, Oxyura, Nomonyx, Stictonetta and Malacorhynchus. The association of Mionetta with oxyurines indicates that the divergence between oxyurines and higher anatids occurred around 25Ma, while the position of Miotadorna within Tadorna indicates that the basal divergence between living Tadorna occurred by the Early-Middle Miocene; together, these two dates indicate that many basal splits within anatids occurred within a short interval during the Miocene. © The Palaeontological Association, 2008.Trevor H. Worthy and Michael S. Y. Le