16 research outputs found

    Evolution in the Genus Rhinella: A Total Evidence Phylogenetic Analysis of Neotropical True Toads (Anura: Bufonidae)

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    True toads of the genus Rhinella are among the most common and diverse group of Neotropical anurans. These toads are widely distributed throughout South America, inhabiting a great diversity of environments and ecoregions. Currently, however, the genus is defined solely on the basis of molecular characters, and it lacks a proper diagnosis. Although some phenetic species groups have traditionally been recognized within Rhinella, the monophyly of some of them have been rejected in previous phylogenetic analyses, and many species remain unassigned to these poorly defined groups. Additionally, the identity and taxonomy of several species are problematic and hinder the specific recognition and description of undescribed taxa. In this work, we first perform phylogenetic analyses of separate mitochondrial and nuclear datasets to test the possible occurrence of hybridiza-tion and/or genetic introgression in the genus. The comparative analysis of both datasets revealed unidirectional mitochondrial introgressions of an unknown parental species into R . horribilis (“ghost introgression”) and of R . dorbignyi into R . bernardoi; therefore, the mitochondrial and nuclear data-sets of these species were considered separately in subsequent analyses. We performed total-evidence phylogenetic analyses that included revised molecular (four mitochondrial and five nuclear genes) and phenotypic (90 characters) datasets for 83 nominal species of Rhinella, plus several undescribed and problematic species and multiple outgroups. Results demonstrate that Rhinella was nonmono-phyletic due to the position of R . ceratophrys, which was recovered as the sister taxon of Rhaebo nasicus with strong support. Among our outgroups, the strongly supported Anaxyrus + Incilius is the sister clade of all other species of Rhinella. Once R . ceratophrys is excluded, the genus Rhinellais monophyletic, well supported, and composed of two major clades. One of these is moderately supported and includes species of the former R . spinulosa Group (including R . gallardoi); the mono-phyletic R . granulosa, R . crucifer, and R . marina Groups; and a clade composed of the mitochondrial sequences of R . horribilis. The other major clade is strongly supported and composed of all the spe-cies from the non-monophyletic R . veraguensis and R . margaritifera Groups, the former R . acrolophaGroup, and R . sternosignata. Consistent with these results, we define eight species groups of Rhinella that are mostly diagnosed by phenotypic synapomorphies in addition to a combination of morpho-logical character states. Rhinella sternosignata is the only species that remains unassigned to any group. We also synonymize nine species, treat three former subspecies as full species, and suggest that 15 lineages represent putative undescribed species. Lastly, we discuss the apparently frequent occurrence of hybridization, deep mitochondrial divergence, and “ghost introgression”; the incomplete phenotypic evidence (including putative character systems that could be used for future phy-logenetic analyses); and the validity of the known fossil record of Rhinella as a source of calibration points for divergence dating analyses.Peer reviewe

    Categorización del estado de conservación de los anfibios de la República Argentina

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    A más de una década de la primera Lista Roja de herpetofauna propuesta por la Asociación Herpetológica Argentina (Lavilla et al., 2000), se recategorizaron los anfibios a partir de nueva información taxonómica, biogeográfica, bio-ecológica y de modificaciones metodológicas respecto a la evaluación anterior. Mediante la participación de 35 especialistas de toda la Argentina se reevaluaron 175 taxones de anfibios (171 en la anterior) incluyendo 23 taxones nuevos para Argentina y obteniéndose como resultado la inclusión de 51 especies en la Lista Roja (8 En Peligro, 11 Amenazadas, 32 Vulnerables), 21 Insuficientemente Conocidas y 103 No Amenazadas. En relación con la categorización anterior de la AHA, los cambios de categorías han sido: un taxón descendió de las categorías En Peligro a Amenazado, siete taxones descendieron de Amenazados o Vulnerables a Insuficientemente Conocidos y nueve de Insuficientemente Conocidos a No Amenazados. Tres No Amenazados y 10 Insuficientemente Conocidos fueron elevados a distintas categorías de amenaza, nueve taxones Vulnerables fueron elevados a Amenazados, cinco de Vulnerables a En Peligro, y un taxón fue elevado de Amenazado a En Peligro. De 23 taxones no evaluados en el 2000, 16 se ubican en la categoría No Amenazados, tres en Insuficientemente Conocidos y cuatro en Vulnerables. Estas modificaciones son el resultado de: (1) mayor información sistemática, biogeográfica y bio-ecológica disponible para la evaluación,(2) cambios en cuanto a las presiones antrópicas sobre las especies o sus hábitats, (3) modificaciones metodológicas que incluyeron instructivos para aplicar los conceptos, la discusión y consenso entre especialistas y el análisis de las incertidumbres.More than a decade after the first red list of herpetofauna proposed by the Asociación Herpetológica Argentina (Lavilla et al., 2000), we recategorized amphibians based on new taxonomic, biogeographical, bio-ecological information and methodological changes in the former evaluation. Through the participation of 35 specialists from all over Argentina 175 taxa of amphibians (171 in the previous categorization) are reevaluated including 23 new taxa added to Argentina, obtaining as results the inclusion of 51 Red List species (8 Endangered, 11 Threatened, 32 Vulnerable), 21 Insufficiently Known and 103 Not Threatened. In relation to the former categorization of the AHA the changes were: one taxon descended from Critically Endangered to Endangered, seven taxa descended from Endangered orVulnerable to Insufficiently Known, and nine from Insufficiently Known to Not Threatened. Three Not Threatened and 10 Insufficiently Known were elevated to different categories of threat, nine taxa were elevated from Endangered to Vulnerable, five from Vulnerable to Endangered, and one from Threatened was elevated to Critically Endangered. Of 23 taxa not evaluated in 2000, 16 are placed as Not Threatened, three Vulnerable, and four Insufficiently Known. These changes are the result of: (1) more available information for evaluation from systematic, biogeography and bio- ecology, (2) changes in human pressures over the species or over their habitats, (3) methodological changes that included recommendations for applying concepts, discussion and consensus among experts and analysis of uncertainties.Asociación Herpetológica Argentin

    Tres nuevos anfibios para la provincia del Chaco (Anura: hylidae y leptodactylidae)

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    Recientes trabajos de campo y revisión de material depositado en colecciones permiten agregar tres nuevas especies de anfibios para la provincia del Chaco: Odontophrynus lavillai Cei, 1985; Hyla pulchella pulchella Duméril & Bibron, 1841 y Scinax berthae (Barrio, 1962).Asociación Herpetológica Argentina (AHA

    The Tadpole of Rhinella azarai

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    Hand and foot musculature of anura : structure, homology, terminology, and synapomorphies for major clades (Bulletin of the American Museum of Natural History, no. 443)

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    155 pages : color illustrations ; 26 cm.Although studies of anuran hand and foot musculature began in the first half of the 19th century, all studies to date have been taxonomically or anatomically restricted in scope, and none has considered the diversity of autopodial myology in Anura as a whole. As a model for future comparisons, we thoroughly describe the hand and foot musculature of an arboreal species (the hylid Triprion petasatus), define the layers in which these muscles are arranged, and attribute presumed functions. On the basis of our myological analysis of 155 species representing 46 of the 54 currently recognized families and main clades of anurans, we describe 20 characters related to hand and foot muscles. Optimization of these characters on the most recent and inclusive phylogenetic hypothesis of Anura results in synapomorphies for several major clades (Bombinatoridae, Alytidae, Xenoanura + Acosmanura, Xenoanura, Pipidae, Acosmanura, Anomocoela, Scaphiopodidae, Pelodytidae + Pelobatidae + Megophryidae, Megophryidae, Neobatrachia, Heleophrynidae, Sooglossidae, Laurentobatrachia, Calyptocephalellidae, Myobatrachoidea, and Nobleobatrachia), including new, nonhomoplastic synapomorphies for clades previously supported only by molecular evidence and a few conflicting phenotypic characters (e.g., Acosmanura, Anomocoela, Neobatrachia). Additionally, we (1) address controversies regarding the homology of anuran and caudate muscles in the context of putative synapomorphies for Ascaphidae + Leiopelmatidae and its sister clade Lalagobatrachia; (2) evaluate a recently proposed terminology for anuran hand and foot musculature; (3) discuss the identities of several hand and foot muscles with problematic homologies; (4) establish a unified terminology for anuran hand and foot muscles, including a list of synonyms for all names employed in the literature; and (5) propose hypotheses for the origin of several myological novelties (neomorphs)

    Prepollex diversity and evolution in Cophomantini (Anura: Hylidae: Hylinae)

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    Several species of Cophomantini are known to have an enlarged prepollex, commonly modified as an osseous spine. We surveyed the osteology and myology of the prepollex and associated elements of 94 of the 190 species of Cophomantini, sampling all genera, except Nesorohyla. Two distinct prepollex morphologies were found: a blade-shaped and a spine-shaped morphology. We described the observed variation in 17 discrete characters to study their evolution in the most inclusive phylogenetic hypothesis for Cophomantini. Both morphologies evolved multiple times during the evolutionary history of this clade, but the origin of the spine-shaped distal prepollex in Boana and Bokermannohyla is ambiguous. The articulation of metacarpal II with the prepollex through a medial expansion of the metacarpal proximal epiphysis is a synapomorphy for Boana. The shape of the curve of the spine, and a large post-articular process of the distal prepollex, are synapomorphies for the Boana pulchella group, the latter being homoplastic in the Bokermannohyla martinsi group. Muscle character states associated with the spine-shaped prepollex are plesiomorphic for Cophomantini. We discuss evolution, function, behaviour and sexual dimorphism related to the prepollical elements. A bony spine is associated with fights between males, but forearm hypertrophy could be more related with habitat than with territorial combat.Fil: Pinheiro, Paulo D. P.. Universidade de Sao Paulo; BrasilFil: Blotto Acuña, Boris Leonardo. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil. Universidade de Sao Paulo; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Ron, Santiago R.. Pontificia Universidad Católica del Ecuador; EcuadorFil: Stanley, Edward L.. University Of Florida. Florida Museum Of History; Estados UnidosFil: Garcia, Paulo C. A.. Universidade Federal de Minas Gerais; BrasilFil: Baptista Haddad, Célio Fernando. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Grant, Taran. Universidade de Sao Paulo; BrasilFil: Faivovich, Julián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

    Data from: Phylogenetic relationships of toads of the Rhinella granulosa group (Anura: Bufonidae): a molecular perspective with comments on hybridization and introgression

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    The Rhinella granulosa group consists of 13 species of toads distributed throughout open areas of South America and Panama. In this paper we perform a phylogenetic analysis considering all but one species of the group, employing five nuclear and four mitochondrial genes, for up to 7910 bp per specimen. Separate phylogenetic analyses under direct optimization (DO) of nuclear and mitochondrial sequences recovered the R. granulosa group as monophyletic and revealed topological incongruence that can be explained mainly by multiple events of hybridization and introgression, both mitochondrial and nuclear. The DO combined analysis, after the exclusion of putatively introgressed or heterozygous genomes, resulted in a phylogenetic hypothesis for the R. granulosa group in which most of the species are recovered as monophyletic, but with interspecific relationships poorly supported. The optimization of morphological (adult and larval), chromosomal, and behavioural characters resulted in 12 putative phenotypic synapomorphies for this species group and some other synapomorphies for internal clades. Our results indicate the need for additional population genetic studies on R. dorbignyi and R. fernandezae to corroborate the taxonomic status of both taxa. Finally, we discuss biological and genetic characteristics of Bufonidae, as possible explanations for the common occurrence of hybridization and introgression observed in some lineages of this family

    The Complex Evolutionary History of the Tympanic Middle Ear in Frogs and Toads (Anura)

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    Most anurans possess a tympanic middle ear (TME) that transmits sound waves to the inner ear; however, numerous species lack some or all TME components. To understand the evolution of these structures, we undertook a comprehensive assessment of their occurrence across anurans and performed ancestral character state reconstructions. Our analysis indicates that the TME was completely lost at least 38 independent times in Anura. The inferred evolutionary history of the TME is exceptionally complex in true toads (Bufonidae), where it was lost in the most recent common ancestor, preceding a radiation of \u3e150 earless species. Following that initial loss, independent regains of some or all TME structures were inferred within two minor clades and in a radiation of \u3e400 species. The reappearance of the TME in the latter clade was followed by at least 10 losses of the entire TME. The many losses and gains of the TME in anurans is unparalleled among tetrapods. Our results show that anurans and especially bufonid toads, are an excellent model to study the behavioural correlates of earlessness, extratympanic sound pathways and the genetic and developmental mechanisms that underlie the morphogenesis of TME structures
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