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1.
In an analysis of data collected between 1954 and 1993, the breeding success of swifts Apus apus was found to have been positively related to temperatures in June, especially in recent years. Adult survival until the next breeding season, by contrast, was found to have been more vulnerable to low temperatures in July, at the end of the breeding season. In addition to the effects of changes in June and July temperatures, both breeding success and survival have shown further long-term trends, increasing and then decreasing through the study period. A simulation integrating all these effects suggests that lifetime reproductive success (LRS) in influenced more by changes in lifespan than annual breeding success, and so fluctutations in July temperatures, but not June temperatures, would have important effects. 相似文献
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Pat. Howard 《e》2009,4(4):e170-e171
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Peter A. Pridmore Thomas H. Rich Pat Vickers-Rich Petr P. Gambaryan 《Journal of Mammalian Evolution》2005,12(3-4):359-378
A partial right humerus has been recovered from the Early Cretaceous (Albian) Eumeralla Formation at Dinosaur Cove in south-eastern
Australia. General morphology, size and the presence of a single epicondylar foramen (the entepicondylar) suggest that the
bone is from a mammal or an advanced therapsid reptile. The humerus is similar in size, shape and torsion to the equivalent
bone of extant and late Neogene echidnas (Tachyglossidae) but, contrary to the situation in extant monotremes, in which the
ulna and radius articulate with a single, largely bulbous condyle, it bears a shallow, pulley-shaped (i.e. trochlear-form)
ulnar articulation that is confluent ventro-laterally with the bulbous radial condyle. This form of ulnar articulation distinguishes
this bone from the humeri of most advanced therapsids and members of several major groups of Mesozoic mammals, which have
a condylar ulnar articulation, but parallels the situation found in therian mammals and in some other lineages of Mesozoic
mammals. As in extant monotremes the distal humerus is greatly expanded transversely and humeral torsion is strong. Transverse
expansion of the distal humerus is evident in the humeri of the fossorial docodont Haldanodon, highly-fossorial talpids and some clearly fossorial dicynodont therapsids, but the fossil shows greatest overall similarity
to extant monotremes and it is possible that the peculiar elbow joint of extant monotremes evolved from a condition approximating
that of the fossil. On the basis of comparisons with Mesozoic and Cainozoic mammalian taxa in which humeral morphology is
known, the Dinosaur Cove humerus is tentatively attributed to a monotreme. However, several apparently primitive features
of the bone exclude the animal concerned from the extant families Tachyglossidae and Ornithorhynchidae and suggest that, if
it is a monotreme, it is a stem-group monotreme. Whatever, the animal's true affinity, the gross morphology of its humerus
indicates considerable capacity for rotation-thrust digging. 相似文献