ESCH, T.*; KRISTAN, W.B.: How the leech decides to swim or crawl In our studies of behavioral choice in the medicinal leech, we have been examining the role that neurons whose somata are located in the anterior brain play in producing behaviors. We found that one neuron, located in sub-packet R3b, has complex effects on […]

BULLOCK, T.H.: An Agenda for Research on Evolution in Brain Complexity Abstract. The span of complexity in brains, between the simplest flatworms and the most advanced mammals is exceedingly great, measured by the number of different anatomical parts, physiological processes, sensory discriminations, and behavioral alternatives in the repertoire. Most evolution of brains has been adaptive […]

LOVEJOY, N; University of Manitoba: Phylogeny and Ontogeny of Needlefishes Heterochrony, defined as evolutionary change in ontogenetic timing, can play an important role in morphological innovation. However, the relative importance of paedomorphosis and peramorphosis remains unclear. The beloniform fishes, including needlefishes, halfbeaks, flyingfishes, ricefishes, and sauries, have long been considered examplars of paedomorphosis. As needlefishes […]

PERES-NETO, Pedro R.; University of Quebec at Trois-Rivieres: Patterns in the co-occurrence of fish species in streams: the role of site suitability, morphology and phylogeny versus species interactions A number of studies at large scales have pointed out that abiotic factors and recolonization dynamics appear to be more important in structuring stream-fish assemblages than biotic […]

SANTINI, F.*; YBAZETA, G.; University of Toronto; University of Toronto: Patterns and processes in the evolution of fishes: an introduction to the symposium Fishes comprises over 50% of all described species of vertebrates. They are present in, and constitute a large part of, the biodiversity of every aquatic ecosystem, and often play a dominant ecological […]

CHOUDHURY, A*; PEREZ-PONCE DE LEON, G; St. Norbert College, DePere; Universidad Nacional Autonoma de Mexico, Mexico D.F.: Parascript studies and the historical biogeography of North American freshwater fishes The historical biogeography of enduring associations between North American freshwater fishes and their metazoan parasites is explored in the tradition of parascript studies (using the language of […]

ARRATIA,, G.; Museum fuer Naturkunde, 10115 Berlin, Germany. gloria.arratia@rz.hu-berlin.de: Origin and Early Radiation of Teleostei The Telesotei and its sister-group the Halecomorphi are currently included in the Division Halecostomi. During the last 30 years, fundamental work concerning the monophyly of the Teleostei, as well as of the Halecomorphi, and the phylogenetic relationships among halecostome subgroups […]

DETTAI, A.; CHEN, W.-J.; BONILLO, C.; LECOINTRE, G.; MNHN, Paris; Univ. Nebraska-Lincoln, Lincoln; MNHN, Paris; MNHN, Paris: New clades within the acanthomorph “radiation” from taxonomic congruence among nuclear and mitochondrial genes In the last two years, decisive steps have been made in favor of a resolution of the famous &laquo bush at the top&raquo of […]

MIYA, M.; NISHIDA, M.; Nat. Hist. Mus. Inst., Chiba; Ocean Res. Inst., Univ. of Tokyo: Major patterns of actinopterygian phylogenies: A new perspective based on >200 complete mitochondrial DNA sequences Actinopterygii, the ray-finned fish, is the most diversified group of all vertebrates, currently comprising over 25,000 species placed in 42 orders, 431 families, and 4075 […]

MARTIN, A. P. ; University of Colorado: Gene duplications and phylogenetic inference of vertebrates: the perils of paralogy Genes are often members of multigene families. Members of multigene families are related by descent. The size of gene families depends on the rate of birth and death of individual genes. Genes are born by gene duplication […]