300 million years of diversification: elucidating the patterns of orthopteran evolution based on comprehensive taxon and gene sampling

Orthoptera is the most diverse order among the polyneopteran groups and includes familiar insects, such as grasshoppers, crickets, katydids, and their kin. Due to a long history of conflicting classification schemes based on different interpretations of morphological characters, the phylogenetic relationships within Orthoptera are poorly understood and its higher classification has remained unstable. In this study, we establish a robust phylogeny of Orthoptera including 36 of 40 families representing all 15 currently recognized superfamilies and based on complete mitochondrial genomes and four nuclear loci, in order to test previous phylogenetic hypotheses and to provide a framework for a natural classification and a reference for studying the pattern of divergence and diversification. We find strong support for monophyletic suborders (Ensifera and Caelifera) as well as major superfamilies. Our results corroborate most of the higher-level relationships previously proposed for Caelifera, but suggest some novel relationships for Ensifera. Using fossil calibrations, we provide divergence time estimates for major orthopteran lineages and show that the current diversity has been shaped by dynamic shifts of diversification rates at different geological times across different lineages. We also show that mitochondrial tRNA gene orders have been relatively stable throughout the evolutionary history of Orthoptera, but a major tRNA gene rearrangement occurred in the common ancestor of Tetrigoidea and Acridomorpha, thereby representing a robust molecular synapomorphy, which has persisted for 250 Myr.Fil: Song, Hojun. Texas A&M University; Estados Unidos. University of Central Florida; Estados UnidosFil: Amédégnato, Christiane. Museum National D; FranciaFil: Cigliano, Maria Marta. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Desutter Grandcolas, Laure. Museum National D; FranciaFil: Heads, Sam W.. University Of Illinois At Urbana; Estados UnidosFil: Huang, Yuan. Shaanxi Normal University; ChinaFil: Otte, Daniel. Drexel University; Estados UnidosFil: Whiting, Michael F.. University Brigham Young; Estados Unido

Blues for the red oxyagrion: A redefinition of the genera acanthagrion and oxyagrion (Odonata: Coenagrionidae)

Examinación de caracteres diagnósticos en todas las especies de Acanthagrion y Oxyagrion muestra que el patrón de coloración por si mismo no es un carácter diagnóstico confiable. Ambos géneros son redefinidos sobre la base de caracteres morfológicos, y algunos caracteres de coloración que proporcionan caracteres adicionales para sus diagnosis. Un análisis filogenético preliminar indica que ambos géneros son monofiléticos. Se distinguen de otros géneros de coenagrionidos neotropicales por sus cercos decumbentes con un tubérculo dorso-basal en machos correlacionado con la presencia de fosas mesepisternales pares en hembras. Acanthagrion y Oxyagrion pueden ser inequívocamente reconocidos por el ancho mínimo del abdomen, forma de la porción distal de la lígula genital y posición de los lóbulos laterales de la ligula genital relativa a la flexura en machos, desarrollo de las carenas mesepisternales y de rayas oscuras medio-dorsales y humerales en hembras, y proporción de laminillas caudales respecto al largo abdominal en últimos estadios larvales. De acuerdo a nuestra redefinición transferimos A. ablutum (una especie ‘azul’), A. hermosae y A. imeriense a Oxyagrion, y O. egleri a Acanthagrion. La posición genérica de ‘A.’ taxaense y ‘O.’ pseudocardinale es cuestionada como dudosa.Examination of diagnostic features for all known species of Acanthagrion and Oxyagrion shows color pattern alone not to be a reliable diagnostic character. Both genera are redefined based on morphological characters, and some color pattern characters which further aid in their diagnoses. A preliminary phylogenetic analysis indicates both genera are monophyletic. They are distinguished from other genera of neotropical coenagrionids by their decumbent cerci with a dorso-basal tubercle in males correlated with the presence of paired mesepisternal fossae in females. Acanthagrion and Oxyagrion can be unequivocally distinguished from each other by the minimum width of abdomen, shape of distal portion of genital ligula and position of lateral lobes of genital ligula relative to flexure in males, development of mesepisternal carinae and of dark mid-dorsal and humeral stripes in females, and ratio of caudal lamellae to abdominal length in ultimate larval instars. According to our redefinition we transfer A. ablutum (a ‘blue’ species), A. hermosae and A. imeriense to Oxyagrion, and O. egleri to Acanthagrion. The generic placement of ‘A.’ taxaense and ‘O.’ pseudocardinale is deemed doubtful.Fil: Von Ellenrieder, Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del NOA. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Museo de Ciencias Naturales. Instituto de Bio y Geociencias del NOA; ArgentinaFil: Lozano, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Limnología "Dr. Raúl A. Ringuelet". Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Limnología; Argentin