COMPARATIVE MORPHOLOGY OF CAECILIAN SPERM (AMPHIBIA, GYMNOPHIONA)

The morphology of mature sperm from the testes of 22 genera and 29 spe cies representing all five families of caecilians (Amphibia: Gymnophio na) was examined at the light microscope level in order to: (1) determ ine the effectiveness of silver-staining techniques on long-preserved, rare material, (2) assess the comparative morphology of sperm quantit atively, (3) compare patterns of caecilian sperm morphology with that of other amphibians, and (4) determine if sperm morphology presents an y characters useful for systematic analysis. Although patterns of sper m morphology are quite consistent intragenerically and intrafamilially , there are inconsistencies as well. Two major types of sperm occur am ong caecilians: those with very long heads and pointed acrosomes, and those with shorter, wider heads and blunt acrosomes. Several taxa have sperm with undulating membranes on the flagella, but limitations of t he technique likely prevented full determination of tail morphology am ong all taxa. Cluster analysis is more appropriate for these data than is phylogenetic analysis. (C) 1994 Wiley-Liss, Inc.