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Magmatic activity in continental arcs is known to vary in a non-steady-state manner, with the mechanisms driving magmatic activity being a matter of ongoing discussion. Of particular importance is the question of what extent episodic magmatism in continental arcs is governed by external factors (e.g., plate motions) and internal factors (e.g., feedback processes in the upper plate). To test existing models for magmatic episodicity, which are mostly based on temporally and spatially limited records, this study uses large data sets of geochronological, geochemical, and plate kinematic data to document the Paleozoic to Mesozoic development of the North and South American Cordilleras in eight transects from British Columbia to Patagonia. The temporal distribution of U/Pb bedrock and detrital zircon ages, used as a proxy for timing of magmatic accretion, shows that some minima and maxima of zircon abundance are nearly synchronous for thousands of kilometers along the arc. Some age patterns are characterized by a periodicity of 50-80 Ma, suggesting a cyclic controlling mechanism. Other magmatic lulls or flare-ups find no equivalents in adjacent sectors, indicating that either discrete events or variable lag times may also be important in governing magmatic activity in continental arcs. Magma composition in Mexico, the Peninsular Ranges, and the Sierra Nevada varies episodically and proportionally with the temporal record of arc activity. During flare-up events, there is an increase in Sm/Yb, indicating deeper melting, and a decrease in εNdi, suggesting a higher degree of crustal assimilation. Geochemical scatter also increases during the initiation of flare-up events. Plate kinematic data provide a means of evaluating mantle heat input. The correlation between plate convergence rate and magmatic accretion varies for each sector, suggesting that different flare-ups or lulls likely reflect variable combinations of processes.

Gustavia montana, a new species of Lecythidaceae from the montane rain forests along the western slopes of Central Cordillera and the northeastern Western Cordillera in Colombia is formally described and illustrated, and its relationship to morphologically closely related species is discussed. Gustavia montana, una nueva especie de Lecythidaceae de los bosques lluviosos montanos de las estribaciones occidentales de la cordillera Central y del noreste de la cordillera occidental de Colombia es formalmente descrita e ilustrada, se discute sus relaciones con las especies morfológicamente cercanas.

We present the first records of the Truandó Toad, Rhaebo haematiticus (Cope, 1862), in the inter-Andean valley of the Middle Cauca River, Colombia, the second largest inter-Andean basin of the country. In Colombia, this species has been extensively documented in the Chocó biogeographic region, on the western slopes of the Cordillera Occidental, in the valley of Magdalena River, and the foothills of the western slope of the northern Cordillera Oriental. Our records help fill an expansive hiatus in the known distribution of this species and increases the number of amphibians known to occur in the basin of the Cauca River.

We describe a new species of Centrolene from the Subandean Cordillera of Kutukú in southeastern Ecuador. The new species differs from all other glassfrogs by the combination of the following characters: presence of processes of vomers but without vomerine teeth; humeral spines in males; dorsum green with light green dots and without dark marks; dorsal skin with abundant tubercles; all visceral peritonea translucent (except for pericardium); and small body size (snout-vent length 21.5–21.9 mm in adult males). The new species is sister to Centrolene camposi from the Western Cordillera of the Andes of southwestern Ecuador, and together they form a clade with C. condor from the Subandean Cóndor Cordillera in southeastern Ecuador. Our time tree suggests that the new species originated at the end of the Pliocene. In addition, we present new information for C. zarza , expanding its geographic range across the southeastern Andes and the Kutukú and Cóndor cordilleras, amending its definition and diagnosis, and offering new information on its natural history and extinction risk. We also discuss the taxonomic status of Ecuadorian populations reported as C. huilensis and conclude that they are C. muelleri based on their close phylogenetic relationships and morphological similarity to samples of C. muelleri from Peru. Centrolene huilensis is a valid species and not closely related to C. muelleri .

Anoura cadenai Mantilla-Meluk & Baker, 2006 is currently known from the Pacific versant of the Cordillera Occidental of Colombia. Based on the review of additional specimens we present a range extension to the southern Cordillera Central and the western slopes of the Cordillera Oriental, extending its range by 30 km north-west, 138 km south, and 155 km southwest; our data also increase the known elevation of the species from 1600 to 1970 m a.s.l. Additionally, we present a summary of the current knowledge regarding the distribution of A. fistulata in Colombia.

The spectacled bear (Ursidae: Tremarctos ornatus) is an emblematic umbrella species and one of the top carnivores in the Andean mountains. It is also listed as vulnerable by IUCN and as endangered by CITES. We analyzed the genetic structure of this species in nine geographical regions representing the three Andean Cordilleras in Colombia. We sequenced six mitochondrial genes in 115 spectacled bears; a subset of these specimens (n = 61) were genotyped at seven nuclear microsatellites. We addressed three objectives: 1) determine the genetic diversity and historical demographic changes of the spectacled bear in Colombia; 2) determine phylogeographic patterns of genetic divergence among spectacled bear populations in Colombia; and 3) estimate the levels of gene flow among different regions of Colombia. Our analyses show evidence of high mitochondrial genetic diversity in spectacled bears, both in Colombia as well as in each of the nine regions, most particularly Norte de Santander, Nariño, and Antioquia-Córdoba. In addition, we detected population expansion in Colombia that occurred around 24,000 years ago, followed by a population decrease during the last 7,000 years, and a sudden expansion in the last 300 years. Phylogenetic analyses showed few well-supported clades, with some haplotypes detected in all the departments and Colombian Andean Cordilleras, and other haplotypes restricted to certain geographical areas (Antioquia, Norte de Santander, Cundinamarca, and Nariño). We detected significant genetic heterogeneity among some departments and among the three Colombian Andean Cordilleras for both mitochondrial and nuclear genes. Nevertheless, the moderate levels of gene flow estimated from FST statistics suggest that geographical barriers have not been definitive obstacles to the dispersion of the spectacled bear throughout Colombia. Despite these gene flow estimates, significant spatial autocorrelation was detected for spectacled bear in Colombia, where two kinds of spatial patterns were discovered: genetic patches of 144 km of diameter, and isolation by distance among bears separated from 578 to 800 km. The two most northern spectacled bear populations of Colombia (Norte de Santander and Antioquia) also were the two most differentiated. Their distinctiveness may qualify them as distinct Management Units (MUs) in the context of conservation policies for the spectacled bear in Colombia.

A new species of is described from the Cordillera del Cóndor, Zamora Chinchipe Province, southeastern Ecuador, based on morphological and molecular data, . The new species is diagnosed from its congeners by the following combination of characters: female SVL 32.5 mm and male SVL 18.3 mm, dorsolateral folds formed by rows of subconical tubercles, strongly areolate ventral skin, two distinct rows of forearm tubercles, one along the ventrolateral margin and a second along the externolateral margin of the forearm, and a prominent yellow groin blotch in the female holotype. The species belongs to the group, part of the subgenus, and is closely related to , , and . Currently, the species is known only from its type locality, where it inhabits low montane evergreen forests at elevations of 1,655-1,830 m. Additionally, we discuss the use of the term \"ulnar tubercles\" in , noting that it may refer to tubercles occupying different positions on the forearm.

We address the possible link between the age of subducting oceanic lithosphere and growth of elevated cordilleras versus extension-dominated arc regions. Singularity exists in South America: the lowest elevated Andean segments are found in Patagonia where the active Chile Ridge enters the trench. Subduction of active ridge triggers thermal doming, crustal extension and attenuation of former cordilleras. At the Antarctica–South America connection, three active ridge subductions induced the disruption of a former continuous cordillera during the opening of Drake Passage. Active ridge subduction induces lithosphere thermal erosion and related crustal extension in the upper plate. Evolution of regions worldwide experiencing ridge subduction confirms this hypothesis.

The Late Triassic conodont species Mockina ex gr. carinata and Mockina ex gr. englandi were exceptionally prevalent among the marine fauna of the Panthalassan realm from the middle Norian through to the Rhaetian. Leading into the complete extinction of conodonts near the Triassic/Jurassic boundary, a significant turnover event occurred in conodont fauna across the Norian/Rhaetian boundary (NRB), with the pectiniform elements of common Rhaetian genera from Tethys exhibiting minimal or absent platforms. This intergeneric trend of platform reduction is not as evident in Panthalassa, where these genera are very rare, but morphometric analyses of M. ex gr. carinata and M. ex gr. englandi specimens from across the Canadian Cordillera demonstrate that comparable shifts in morphology occurred intraspecifically in Panthalassa across the NRB, confirming the global extent of these trends. Pectiniform elements of M. ex gr. carinata display a sequential reduction of platform width from the middle Norian to late Norian to Rhaetian, whereas pectiniform elements of M. ex gr. englandi display a reduction of platform width only from the late Norian to Rhaetian. Specimens of both species that have a mid-platform length to breadth ratio greater than 3:1 are restricted to the Rhaetian. Specimens from the Kennecott Point section on Haida Gwaii, British Columbia, demonstrate that this morphological shift occurred somewhat later than other biostratigraphic proxies for the NRB. The global trend of platform width reduction in many conodont pectiniform elements may reflect a change in primary diet away from hard food sources, perhaps suggesting some degree of carbonate biomineralization suppression beginning around the NRB. This interpretation would support CO2 outgassing as the causal mechanism of the environmental disturbance at the NRB and identify the NRB as a significant turning point for Late Triassic ecosystems, marking the beginning of a protracted, multiphase end-Triassic mass extinction.