摘要:

Ossom's Eyrie Cave, a small cave in the face of a limestone cliff, has yielded an extensive vertebrate fauna which documents important changes over the last 2000 years. There seem to be three major contributions to the fauna. A short‐lived Romano‐British occupation provides dating evidence for the lower levels, and may have contributed a few bones of larger species (sheep/goat, pig, fowl). A golden eagle nested on the cave ledge at a later time, and brought as food medium to large birds and mammals, including black grouse, raven, polecat, pine marten, juvenile fox, badger, roe deer and wild boar. Many of these species are locally extinct. There is an extensive small mammal fauna of over 4200 individuals, which occurs throughout the deposits and dominates the top layers representing the diet of a barn owl. Important changes in this fauna include the sudden decline of the water vole from around 7% in the earlier layers to less than 1% in the top layers and the disappearance of the dormo

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1990.tb01217.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The investigation of the development of the trigeminal jaw adductor musculature in the turtleChelydra serpentinadocuments the early aggregation of muscle rudiments around the innervating nerve branches, probably a consequence of inductive interaction. This may explain the early continuity of the intramandibularis with the intermandibularis muscle. Several aspects of muscle development differ in the turtle as compared to lizards. These differences highlight the fact that conjectures of homology, based on a static topographical correspondence of adult structures, cannot capture the dynamics of the developmental process. The intramandibularis muscle of turtles, comparable to that of crocodiles, represents a plesiomorphous structure which is not homologous to the intramandibularis muscle of lacertoid lizards, a derived feature of the Lacertoidea. A derived feature of the chelonian jaw adductor musculature is the posterodorsal expansion of the external adductor along a supraoccipital crest, developing according to a pattern of Haeckelian recapitulation. Muscle development serves to corroborate the concept of a monophyletic Eureptilia, including diapsids and synapsids, as opposed to the (paraphyletic) Anapsida. The impact of the differentiation of the external adductor into a pulley system on cranial kinesis is analysed in biomechanical terms.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1990.tb01218.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

The occurrence of villi (outgrowths, projections) on the bases of the basalmost downy barbulcs of breast‐feathers is documented with scanning electron microscopy. The presence of these structures is thought to constitute a synapomorphic character for Passeriformes, Trochilidac, Capitonidac, Indicatoridae, Ramphastidae, and Picidae, which once more casts suspicion on the monophylv of Wetmore's order Piciforme

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1990.tb01219.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

Hearts from 20 mammalian orders were examined according to a fixed protocol to determine if the gross differences of shape and internal anatomy could be explained. Three generalizations can be made: firstly differences are most closely related to taxonomic position, secondly some features, such as the prominence of the conus of the right ventricle in animals that leap, dig or sprint regularly as part of their defence mechanism and a long, narrow left ventricle in endurance performers may be more closely related to activity than ancestry, and lastly some characteristics may be pleiotropic effects of thoracic morphogenesis.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1990.tb01220.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1990.tb01217a.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY