Sur la d\ue9couverte de Characidae (Pisces, Cypriniformes) dans l\u27Eoc\ue8ne Inf\ue9rieur fran\ue7ais

Volume: 88Start Page: 175End Page: 17

THE PHYLOGENETIC RELATIONSHIPS AMONG REQUIEM AND HAMMERHEAD SHARKS: INFERRING PHYLOGENY WHEN THOUSANDS OF EQUALLY MOST PARSIMONIOUS TREES RESULT

Protein variation among 37 species of carcharhiniform sharks was examined at 17 presumed loci. Evolutionary trees were inferred from these data using both cladistic character and a distance Wagner analysis. Initial cladistic character analysis resulted in more than 30 000 equally parsimonious tree arrangements. Randomization tests designed to evaluate the phylogenetic information content of the data suggest the data are highly significantly different from random in spite of the large number of parsimonious trees produced. Different starting seed trees were found to influence the kind of tree topologies discovered by the heuristic branch swapping algorithm used. The trees generated during the early phases of branch swapping on a single seed tree were found to be topologically similar to those generated throughout the course of branch swapping. Successive weighting increased the frequency and the consistency with which certain clades were found during the course of branch swapping, causing the semi-strict consensus to be more resolved. Successive weighting also appeared resilient to the bias associated with the choice of initial seed tree causing analyses seeded with different trees to converge on identical final character weights and the same semi-strict consensus tree. The summary cladistic character analysis and the distance Wagner analysis both support the monophyly of two major clades, the genus Rhizoprionodon and the genus Sphyrna. . The distance Wagner analysis also supports the monophyly of the genus Carcharhinus . However, the cladistic analysis suggests that Carcharhinus is a paraphyletic group that includes the blue shark Prionace glauca .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73088/1/j.1096-0031.1992.tb00073.x.pd

The fossil vertebrates from Laño (Basque Country,Spain); new evidence on the composition and affinities of the Late Cretaceous continental faunas of Europe

[ES]Recientemente se han descubierto fósiles en la localidad Laño (País Vasco), un conjunto de vertebrados de edad Maastrichtiano probablemente compuesto por peces, anfibios, reptiles y mamíferos. Se amplía considerablemente nuestro conocimiento de las faunas continentales del Cretácico Superior de Europa, hasta ahora basada en un registro mucho menos completo. Algunos taxones se citan por primera vez en Europa, y la fauna también es la más antigua conocida. La asociación de Laño revela una fauna original que incluye tanto las formas conexas de Asia, Norte de América y los elementos de los grupos con afinidades Gondwana.[EN] A newly discovered fossil locality at Laño (Basque Conuntry) has yielded a vertebrate assemblage of probably Maastrichtian age comprising fishes, amphibians, reptiles and mammals. It considerably enlarges our knowledge of the Late Cretaceous continental faunas of Europe, hitherto based on a much less complete record. Some taxa are recorded for the first time in Europe, and the fauna also contains the oldest known. The Laño assemblage reveals an original fauna comprising both forms related to Asian and North American groups and elements with Gondwanan affinities