摘要:

The auditory bulla is a much‐scrutinized taxonomic character of mammals, which is generally regarded as showing a high degree of structural consistency within higher taxa. Observations of bulla variability in populations of the marsupialPhalanger orientalisfrom the Solomon Islands demonstrate considerable flexibility in bulla makeup, with variable incorporation of the squamosal into the tympanic floor. Studies of the ontogeny of the bulla inPhalangershow the presence of three ossification centres, including an entotympanic. Squamosal invasion of one of these ossificiation centres is seen as a possible result of inbreeding, arising from the mode of colonization of the Solomon Islands by this species. This suggests that, under certain conditions, considerable morphological plasticity may be induced within the selective constraints of bulla functio

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1993.tb00215.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Previous studies of rodent appendicular morphology suggest that digging activity induces changes in long bones, producing shorter and thicker structures. Subsequent hypotheses have been tested in Ctenomyinae, a group of octodontid rodents globally adapted to subterranean life. Slopes of the equations calculated for extant animals and their corresponding confidence intervals agree with expectations in almost all cases. Results on fossil taxa are less clear, but suggest a morphocline from a plesiomorphic condition of the appendicular skeleton, present in the fossil genera, departing little from that of the current epigeous rodents, to a more derived long bone design in the species of the living genusCtenomys, in accordance with their digging activity.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1993.tb00216.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The systematic status of theRousettus aegyptiacuspopulations of the oceanic islands of Principe and São Tomé in the Gulf of Guinea (West Africa) is examined. These populations present noticeable phenctic differences between themselves as well as among theR. a. unicolorpopulations of Gulf of Guinea continental coast and those of Bioco island. The differences found justify the description of new subspecies on the two islands. In spite of the differences among the insular subspecies, these share some features that, at least partially, suggest the existence of a common evolutionary histor

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1993.tb00217.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

The validity of 18 genera of small (skull length less than 150 mm) dicynodonts with postcanine teeth has been assessed. It is concluded that only four genera,Emydops, Eodicynodon, RobertiaandPristerodon, can be defined satisfactorily on the basis of well‐preserved and adequately prepared specimens. Of the remaining 14 genera, ten are not valid and may be accommodated within the four well‐characterized genera. Three additional genera (Chelyoposaurus, KoupiaandTaognathus) should becomenomina nudasince they are based on inadequately diagnosed material which in the case of the first two genera is now lost.Brachyprosopus, although based on a single somewhat inadequate specimen, is also considered valid although future examination of the type (not seen by us) may require reassessment of this opinion.We discuss briefly the nature of the taxonomic characters used, and the stratigraphic distribution of the four major gen

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1993.tb00218.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Both sexes of the ephippigerinesSteropleurus stallandS. nobreican stridulate and produce multisyllabic calls which are described. Female stridulation is in response to the conspecific male call. In both species cither sex can perform phonotaxis on the call of the conspecific member of the opposite sex, but ignore the calls of other species. The parameters of the calls are examined with the conclusion that the only reliably distinctive feature is the modal or carrier frequency generated during stridulation. There are frequency differences between male and female calls in both species. Males only perform phonotaxis on female replies generated in response to their own call, implying that there is also some time window involved. Male phonotaxis was faster and more accurate than that of the female. Acoustic rivalry and aggression were also noted, particularly in females.

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1993.tb00219.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Dung Beetle Ecology, edited by I. Hanski and Y. Cambefort.The Environmental Impact of Burrowing Animals and Animal Burrows (Symposia of the Zoological Society of London No. 63), edited by P. S. Meadows and A. Meadows.Mammoths, Mastodonts and Elephants, by G. HaynesMajor Events in the History of Life, edited by J. W. Schopf.Thomas Horsfield's Zoological Researches in Java and the Neighbouring Islands, with a memoir by J. Bastin.Reproductive Biology of the Invertebrates, Vol. IV Part B, Fertilization, Development and Parental Care, edited by K. G. Adiyodi&R. G. Adiyodi

ISSN:0024-4082    

DOI:10.1111/j.1096-3642.1993.tb00220.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY