RESUMEN
Mitonuclear discordance is a frequently encountered pattern in phylogeographic studies and occurs when mitochondrial and nuclear DNA display conflicting signals. Discordance among these genetic markers can be caused by several factors including confounded taxonomies, gene flow, and incomplete lineage sorting. In this study, we present a strong case of mitonuclear discordance in a species complex of toads (Bufonidae: Incilius coccifer complex) found in the Chortís Block of Central America. To determine the cause of mitonuclear discordance in this complex, we used spatially explicit genetic data to test species limits and relationships, characterize demographic history, and quantify gene flow. We found extensive mitonuclear discordance among the three recognized species within this group, especially in populations within the Chortís Highlands of Honduras. Our data reveal nuclear introgression within the Chortís Highlands populations that was most probably driven by cyclical range expansions due to climatic fluctuations. Though we determined introgression occurred within the nuclear genome, our data suggest that it is not the key factor in driving mitonuclear discordance in the entire species complex. Rather, due to a lack of discernible geographic pattern between mitochondrial and nuclear DNA, as well as a relatively recent divergence time of this complex, we concluded that mitonuclear discordance has been caused by incomplete lineage sorting. Our study provides a framework to test sources of mitonuclear discordance and highlights the importance of using multiple marker types to test species boundaries in cryptic species.
Asunto(s)
Núcleo Celular , ADN Mitocondrial , Animales , Bufonidae/genética , Núcleo Celular/genética , América Central , ADN Mitocondrial/genética , Honduras , FilogeniaRESUMEN
BACKGROUND: Recent studies have begun to reveal the complex evolutionary and biogeographic histories of mainland anoles in Central America, but the origins and relationships of many taxa remain poorly understood. One such group is the Anolis (Norops) crassulus species subgroup, which contains ten morphologically similar highland taxa, the majority of which have restricted distributions. The nominal taxon A. crassulus has a disjunct distribution from Chiapas, Mexico, through Guatemala, in the highlands of El Salvador, and in the Chortís Highlands of Honduras. We test the relationships of these species using multiple mitochondrial and nuclear loci in concatenated and multispecies coalescent frameworks, in an effort to both resolve long-standing taxonomic confusion and present new insights into the evolution and biogeography of these taxa. RESULTS: Sequences of multiple mitochondrial and nuclear loci were generated for eight of the ten species of the Anolis crassulus species subgroup. We analyzed phylogenetic relationships and estimated divergence times and ancestral ranges of the subgroup, recovering a monophyletic subgroup within Anolis. Within the nominal taxon Anolis crassulus, we recovered multiple genetically distinct lineages corresponding to allopatric populations, and show that the Chortís Highland lineage split from the others over 13 MYA. Additionally, distinct mitochondrial lineages are present within the taxa A. heteropholidotus and A. morazani, and importantly, samples of A. crassulus and A. sminthus previously used in major anole phylogenetic analyses are not recovered as conspecific with those taxa. We infer a Chortís Highland origin for the ancestor of this subgroup, and estimate cladogenesis of this subgroup began approximately 22 MYA. CONCLUSIONS: Our results provide new insights into the evolution, biogeography, and timing of diversification of the Anolis crassulus species subgroup. The disjunctly distributed Anolis crassulus sensu lato represents several morphologically conserved, molecularly distinct anoles, and several other species in the subgroup contain multiple isolated lineages.
Asunto(s)
Ecosistema , Lagartos/clasificación , Filogeografía , Animales , Teorema de Bayes , América Central , ADN Mitocondrial/genética , Sitios Genéticos , Lagartos/genética , Nepovirus , Filogenia , Análisis de Secuencia de ADN , Especificidad de la Especie , Factores de TiempoRESUMEN
Moss salamanders (genus Nototriton) are represented in northern Central America by nine putative species: N. barbouri, N. brodiei, N. lignicola, N. limnospectator, N. mime, N. picucha, N. saslaya, N. stuarti, and N. tomamorum. I estimate the phylogenetic relationships for these species based on data from three mitochondrial gene fragments (16S, cytochrome b, and COI), and compare morphological variation among putative taxa. As evidenced here and in previous studies, the taxon N. barbouri is paraphyletic with respect to populations from the Cordillera Nombre de Dios in northern Honduras. I restrict this taxon to populations from the Sierra de Sulaco in central Yoro, Honduras, and describe two new species from the Cordillera Nombre de Dios.
Asunto(s)
Urodelos/anatomía & histología , Urodelos/clasificación , Animales , ADN Mitocondrial , Femenino , Honduras , Masculino , Filogenia , Análisis de Secuencia de ADN , Especificidad de la Especie , Urodelos/genéticaRESUMEN
A new species of palm-pitviper of the genus Bothriechis is described from Refugio de Vida Silvestre Texíguat in northern Honduras. The new species differs from congeners by having 19 dorsal scale rows at midbody, a bright green dorsal coloration in adults, the prelacunal scale fused to the second supralabial, and in representing a northern lineage that is sister to Bothriechis lateralis, which is distributed in Costa Rica and western Panama and is isolated from the new taxon by the Nicaraguan Depression. This represents the 15th endemic species occurring in Refugio de Vida Silvestre Texíguat, one of the richest herpetofaunal sites in Honduras, itself being the country with the highest degree of herpetofaunal endemism in Central America. We name this new species in honor of a Honduran conservationist slain in fighting against illegal logging, highlighting the sacrifices of rural activists in battling these issues and the critical importance of conservation in these areas.
ResumenUna nueva especie de tamagás verde del género Bothriechis se describe del Refugio de Vida Silvestre Texíguat en el norte de Honduras. La nueva especie difiere de sus congéneres por tener filas de 19 escamas dorsales en la mitad del cuerpo, una brillante coloración verde en la porción dorsal del cuerpo en adultos, la escama prelacunal fusionada con la segunda supralabial, y en representación del linaje del norte que es clado hermano de Bothriechis lateralis, la cual se distribuye en Costa Rica y el Occidente de Panamá y está aislada del nuevo taxón por la Depresión de Nicaragua. Representa la decimoquinta especie endémica encontrada en el Refugio de Vida Silvestre Texíguat, uno de los lugares más ricos de herpetofauna en Honduras, el país con el más alto grado de endemismo de la herpetofauna en Centroamérica. Nombramos esta nueva especie en honor a un conservacionista Hondureño asesinado en contienda contra la tala ilegal, destacando los sacrificios de los activistas rurales luchando frente a estos problemas y la importancia crítica de la conservación en estas áreas.
RESUMEN
The highlands of northeastern Honduras remain under-characterized in terms of biological diversity, as exemplified by the regularity of new amphibian and reptile taxa discoveries. Following the recent description of a new species of Nototriton from the Sierra de Agalta in northeastern Honduras, we report the discovery of a second new species of Nototriton from the nearby Parque Nacional Montaña de Botaderos. This new taxon, Nototriton mime sp. nov., is distinguished from other Nototriton by its distinctive pale brown dorsal coloration in adult males, relatively large nares, a relatively broad head, mitochondrial sequence divergence, and phylogenetic relationships, and is geographically isolated from other populations of Nototriton.
Asunto(s)
Urodelos/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Tamaño Corporal , Femenino , Honduras , Masculino , Datos de Secuencia Molecular , Tamaño de los Órganos , Filogenia , Urodelos/anatomía & histología , Urodelos/genética , Urodelos/crecimiento & desarrolloRESUMEN
Myxomycetes are protists whose life cycle depends on aerially dispersed spores that germinate into motile myxamoebae, which then pair and fuse to form a larger, motile plasmodium. The plasmodium seeks out a suitable fruiting site (usually atop vegetative material or detritus) and transforms into fruiting bodies that release the spores. In this paper we report the first known instance of a myxomycete, in this case Physarum pusillum, sporulating on the body of a living animal, the cryptic lizard Corytophanes cristatus, which was collected in eastern Honduras in 2003.