A survey of prepollex and prehallux variation in anuran limbs

This paper reviews skeletal variation of the prepollex and prehallux among anurans and analyses their ontogeny in neotropical species. Morphological d iversity is related to the number and features of distal elements. In some groups, clear phylogenetic trends may be interpreted from prepollical and/o r prehallical reduction. However, specialized patterns converge from simila r habit or behaviour. Developmental data are considered for discussing homo logy hypotheses and also to interpret evolutionary changes of anuran prepol lex and prehallux morphologies. There is an apparent invariance in the pres ence of these structures that suggests the prepollex and prehallux were int egrated, conserved and evolved in the plan of anuran limbs. (C) 2001 The Li nnean Society of London.