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Patterns of diversification in species-rich clades provide insight into the processes that generate biological diversity. We tested different models of lineage and phenotypic diversification in an exceptional continental radiation, the ovenbird family Furnariidae, using the most complete species-level phylogenetic hypothesis produced to date for a major avian clade (97% of 293 species). We found that the Furnariidae exhibit nearly constant rates of lineage accumulation but show evidence of constrained morphological evolution. This pattern of sustained high rates of speciation despite limitations on phenotypic evolution contrasts with the results of most previous studies of evolutionary radiations, which have found...
Categories: Publication; Types: Citation; Tags: Evolution
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Despite some remarkable recent discoveries, the Mesozoic fossil record of salamanders remains limited, particularly for the Jurassic. Here we describe the first articulated salamander skeleton from the Jurassic of Euramerica, recovered from Upper Jurassic deposits of the Morrison Formation, Dinosaur National Monument, USA. The specimen was studied using both conventional methods and high-resolution computed tomography. It shows a combination of primitive and derived character states that distinguish it from all known Mesozoic salamanders and which permit the erection of a new genus and species, Iridotriton hechti. The derived states (including the presence of spinal nerve foramina in the tail) suggest a position...
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Causes of interspecific variation in growth rates within and among geographic regions remain poorly understood. Passerine birds represent an intriguing case because differing theories yield the possibility of an antagonistic interaction between nest predation risk and food delivery rates on evolution of growth rates. We test this possibility among 64 Passerine species studied on three continents, including tropical and north and south temperate latitudes. Growth rates increased strongly with nestling predation rates within, but not between, sites. The importance of nest predation was further emphasized by revealing hidden allometric scaling effects. Nestling predation risk also was associated with reduced total...
Categories: Publication; Types: Citation; Tags: Evolution
We explore the potential for applying broad ecological theories to interactions between soil animals and micro-organisms to generate a predictive framework within which more hypothesis led research can be undertaken. The paper stems from discussions during a workshop at the XIVth International Symposium on Soil Zoology. The possible linkage between biodiversity and ecosystem functions forms a good example of how soil zoology research can be productively stimulated by addressing a broader ecological concept but also how the concept can be tested below ground at fundamentally different scales to those commonly used above ground. Other areas of theory rapidly developing above ground, which are yet to be fully tested...
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The colonial nesting Village Weaver (Ploceus cucullatus) lays eggs that vary in ground color and pattern, but individual females lay similar eggs each time. Tests on captive African stocks have shown that females reject eggs of other cohorts if such eggs are sufficiently different.
Categories: Publication; Types: Citation; Tags: Evolution


map background search result map search result map A Late Jurassic salamander (Amphibia: Caudata) from the Morrison Formation of North America A Late Jurassic salamander (Amphibia: Caudata) from the Morrison Formation of North America